JB_Version#7_2012 nach Druckerei

Annual Report
2010.2011
Publisher:
NaMLab gGmbH (Nanoelectronic Materials Laboratory)
Executives:
Prof. Dr.-Ing. Thomas Mikolajick , Scientific Director
Dr. rer. nat. Alexander Ruf, Financial Director
Mail/Visitor address: Noethnitzer Str. 64
01187 Dresden, Germany
Phone:
+49.351.2124990-00
Fax:
+49.351.47583900
E-Mail:
[email protected]
Internet:
http://www.namlab.com
Front Page:
Bonded CMOS transistor test chip for reliability
measurements at elevated temperatures
Photos:
NaMLab
Editor/Layout: Mandy Grobosch/Uwe Schröder
© NaMLab gGmbH, Dresden 2012
All rights reserved.
Contents
Preface
1
NaMLab Profile
2
NaMLab Team
3
Dielectric Materials
Capacitor Dielectrics
4
Diffusion Barriers
5
Re-configurable Devices
HfO2-based Ferroelectric Field-Effect Transistor
7
Si-Nanowire based Devices
8
Resistive Memory and Memristor
9
Carbon-based Devices
10
Energy Efficiency Devices
Gallium Nitride Material and Devices
12
Dye-based Solar Cells
13
Passivation Layers for Solar Cells
14
Si-Nanowire Anodes for Li-Ion Batteries
15
Photodiodes
16
Competences
Electrical Characterization
18
Physical Characterization
19
Device Reliability
20
Optical Characterization
21
Facts & Figures
NaMLab in Numbers
23
Cooperations
24
Projects
25
NaMLab goes public
26
NaMLab in the Press
27
Publications 2010/2011
28
Preface
Prof. Dr.-Ing. Thomas Mikolajick
Excellence, flexibility & speed have always been key attributes of the nano- and microelectronic business. A research
institute tied to this business should follow these attributes
and envision changes as a chance. The semiconductor industry as well as the micro- and nanoelectronics cluster in Saxony
experienced a steep downturn during the years 2008 and
2009. As a severe consequence of this downturn the industrial stack holder of NaMLab had to withdraw its ownership.
Consequently the business model as well as the scientific focus of NaMLab had to be significantly changed in the second
half of 2009. This process led to new scientific topics and projects as well as a number of excellent technical and scientific
results in 2010 and 2011. This first biennial report covers this
important re-orientation period of the NaMLab activities.
Today NaMLab is a well-established research institute integrated into the world class micro- and nanoelectronics environment in Saxony, particularly in its capital Dresden. Based
on key expertise in dielectric materials for semiconductor devices NaMLab now focuses on the integration and application
of its materials expertise applied to re-configurable and energy efficiency devices.
Electrical characterization with a focus on device reliability is
an important NaMLab key competence of its own. Although
mostly embedded into fundamental material or device research oriented projects, researchers at NaMLab advance existing electrical characterization techniques and contribute to
significant developments for both sectors, industry and academia.
Despite the challenging re-orientation in 2009, NaMLab enterprises have been very successfully accomplished within the
last two years. The re-programmable nanowire Schottkybarrier field-effect-transistor, ferroelectric devices based on
doped HfO2 and the promising start into the development of
devices based on the wide band-gap compound Gallium Nitride are three of the important highlights of this period. Not
just in these, also in topics like memristors and solar cells
NaMLab results have attained national and international recognition in both, the industrial and scientific world. Very positive feedback from customers and partners as well as numerous scientific publications demonstrate the successful path
NaMLab has taken in the past years. The NaMLab team will
built on these merits and further extend successfully initiated
ventures contributing to the exciting and challenging world of
nano- and microelectronics.
Prof. Dr.-Ing. Thomas Mikolajick
1
NaMLab Profile
NaMLab gGmbH is a non-profit research organization and associated institute of the Technical University (TU) Dresden
with focus on materials for electronic devices. Material development at NaMLab commonly proceeds under the constraints
of the target electron device. The focus of the material development is therefore highly integration and application driven.
Historically NaMLab was founded as a joint venture between
Infineon Technologies AG memory products division (which
later became Qimonda) and the Technical University Dresden.
Therefore in the first years the research activities were focused on future high-k materials for capacitors in dynamic
random access memories (DRAM) which was the main product of the industrial parent company. After the step-out of the
industrial partner mid 2009 this key know-how was transformed to other devices and application fields. Today NaMLab
employs these core competences to develop new device concepts in two central fields:


Re-Configurable Devices and
Energy Efficiency Devices
The research activities of NaMLab are focused around three core topics. Building on
its strength in dielectric materials, NaMLab’s research focuses on Re-Configurable
Devices and Energy Efficiency Devices
Dielectric Materials
• Capacitor Dielectrics
Re-Configurable Devices aim at electronic solutions beyond
the possibilities of leading edge CMOS devices according to
Moore´s Law. Re-programmable silicon-nanowire transistors,
memristors and a new type of ferroelectric field-effect transistor based on doped hafnium oxide are the dominant topics in
this field. In Energy Efficiency Devices NaMLab works at the
frontier of research for solutions which reduce the power consumption of electronic devices and increase the overall energy conversion efficiency in entire electronic systems.
• Diffusion Barriers
While the first topic includes a number of device-advancing
activities in traditional CMOS processes, the second addresses specific dielectrics-based solutions for solar cells and
GaN-based devices and systems. Besides the two focus device areas the fundament of this research, namely dielectric
materials, is a key topic of its own. Here NaMLab either
strives to advance the material properties themselves or is
applying its know-how to non-electrical properties of the materials relevant for electron devices. The development of advanced diffusion barriers for organic electronic devices is a
prime example. Additionally the measurement of electrical
properties is a key competence needed in all topics.
• Resistive Memory and Memristor
In most of its research activities in GaN-based devices, solar
cells and ferroelectric field effect transistors NaMLab is
closely working together with industrial partners. Basic research is done in close co-operation with the Technical University Dresden and other research centers like Helmholtz Zentrum Dresden-Rossendorf (HZDR) and the Leibniz Institute for
Solid State and Materials Research Dresden (IFW) to continuously generate new innovative ideas and approaches.
• Photodiodes
Prof. Dr.-Ing. Thomas Mikolajick
2
Re‐Configurable Devices
• Si‐Nanowire based Devices
• HfO2‐based Ferroelectric Devices
• Carbon‐based Devices
Energy Efficiency Devices
• Gallium Nitride based Devices
• Dielectrics for Solar Cells
• Si‐Nanowire Anodes for Batteries
Overview of Research Activities at NaMLab
The NaMLab Team
Capacitor Dielectrics
Materials with high dielectric constants (high-k materials) play
an increasingly important role in nano-electronic devices. For
conventional semiconductors charge is stored in capacitors.
New dielectric materials with higher dielectric constants have
to be introduced in order to maintain the storage capacity of
capacitors which are continuously being designed with
smaller areas. Similar dielectric materials are needed for the
next generation of high performance transistor devices as
well as processors and logic products. A variety of research
projects in the nano-scale regime are ongoing in order to gain
an understanding of the influence of material properties with
respect to leakage mechanisms, performance, speed and reliability.
For capacitor applications (see Fig. 1) the main focus was on
CaTiO3, ZrO2- and TiO2-based dielectrics. For crystalline layers
aluminum and strontium doped ZrO2 with a dielectric constant of ~40 and a band gap of ~6 eV resulted in metalinsulator-metal capacitors with an equivalent oxide thickness
(EOT) down to 0.9 nm at target leakage current (1x10-7 A/
cm² , see Fig. 2). Even better capacitance performance was
reached for TiO2-based dielectrics like CaTiO3 and SrTiO3 (in
collaboration with RWTH Aachen). Both materials show EOT
values of 0.5-0.6 nm at target leakage condition when they
are deposited on noble metal electrodes like platinum. If a
bottom electrode with optimized lattice mismatch (e.g.
SrRuO3) is introduced the EOT value can be further reduced to
~0.3 nm. ZrO2 dielectrics are already in DRAM production and
TiO2-based materials are in discussion to be introduced in
next generation products.
Parallel to the development of new dielectric materials characterization techniques are evaluated to compare macroscopic with microscopic measurements. Conductive atomic
force microscopy (cAFM) was adapted as a tool for localized
leakage current characterization. For Al:ZrO2 and Sr:ZrO2 an
increased leakage current at grain boundaries was detected
(see Fig. 3). Variable temperature current vs. voltage measurements revealed a trap assisted leakage mechanism with a
trap depth of ~0.8 eV which is typically related to oxygen vacancies in these materials. The lifetime of capacitors was determined to be longer than 10 years for 7 nm HfO2/ZrO2 or
close to 10 years for 12 nm SrTiO3 dielectrics.
Fig. 1: Cross-sectional HRTEM micrographs
of CaTiO3 layer between Ru and Pt electrodes.
Fig. 2: Leakage current density vs. equivalent oxide thickness for MIM capacitor
stacks with different high-k materials characterized at NaMLab.
In future, further candidate materials will be continuously
screened and characterized for new device applications. The
application of the materials to non-capacitor applications is
becoming more and more important.
Cooperation:
München
RWTH Aachen, Fraunhofer CNT, Hochschule
Publications: J3, J6, J7, J11, J13, J14, J15, J17, J21, J29, T2,
T3, T4, T8, T11, T12, T17, T19, T25, T31, C1, C2
Contact: Dr. Uwe Schröder
4
Fig. 3: (a) AFM image of an Al:ZrO2 sample
confirms grain size of about 100 nm. (b) CAFM of the same sample shows that leakage current flows mainly along grain
boundaries.
Diffusion Barriers
Fig. 1: AFM micrograph shows 100 nm Al2O3
structures within the Al2O3 layer on foil substrates.
Fig. 2: As extracted further from XRR, density of Al2O3 layers increases and the growth
per cycle decreases with increasing cycle
times, indicating reduced incorporation of -C
and -OH groups.
Organic light emitting diodes (OLEDs) are getting increasingly
common in electronic device applications due to their high
power efficiency and low cost of manufacturing. However, the
organic materials in the OLEDs are very sensitive to atmospheric moisture and oxygen. Contacts with moisture or oxygen affect the device operation and performance. State-of-the
-art encapsulation for OLEDs is a glass-glass encapsulation,
resulting in a device that is bulky, brittle and fragile. An alternative to this standard encapsulation would be a thin film
structure deposited using atomic layer deposition (ALD). ALD
is a self-limiting growth method that results in highly conformal layers at low deposition temperatures which are ideal for
avoiding H2O vapor and oxygen diffusion. Low growth temperatures would further allow protection of OLED devices on
technologically advantageous flexible plastics substrates by
ALD diffusion barriers.
Research on OLED encapsulation at NaMLab has begun with
thin Al2O3 layers (10-50 nm thick) deposited in the temperature range between 50°C and 100°C on flexible PET
(Polyethylenterephthalat), PEN (Polyethylennaphthalat) foils,
control Si substrates and direct barriers layers on OLEDs by
means of atomic layer deposition using TMA and Ozone as
precursors. The ALD parameters at each deposition temperature were optimized to get the best barrier properties at this
temperature by varying the precursors pulse and purge
lengths. Film thickness, density, and microstructure were
evaluated using X-Ray reflectometry (XRR) and Atomic Force
Microscopy (AFM) measurements respectively. In Fig. 1 an
AFM micrograph of deposited films is depicted showing sub100 nm sized Al2O3 structures within the Al2O3 layer. Samples
produced with varying O3 pulse times show a reduction in surface roughness (calculated from AFM images) with increasing
O3 pulse times.
The barrier properties of these samples were tested with the
help of a calcium layer structure, which consisted of a thin
layer of metallic calcium on a glass substrate protected by an
Al2O3 layer whose barrier properties need to be investigated.
Water vapor escaping through the Al2O3 layer decomposes
metallic calcium into transparent Ca(OH)2, which can be observed optically or electrically by recording conductivity of metallic calcium. From the slope of the conductivity vs. time
curve, water vapor transmission rates (WVTR) of the Al2O3
layer can be calculated (Fig. 3). The WVTR reduces with increasing thickness indicating better encapsulation.
In addition to pure Al2O3 diffusion barrier layers in future also
nanolaminate film stacks of different materials will be evaluated. Al2O3 layers will be interchanged with other organic or
inorganic materials.
Fig. 3: WVTR values decrease with increasing Al2O3 film thickness due to better coverage of the Ca test structures by the Al2O3
diffusion layer.
Cooperation: Technische Universität Dresden (IHM, IAPP),
FILK, Novaled,
Contact: Dr. Aarti Singh
5
Re-Configurable Devices
HRSEM picture of a single nanowire inverter
HfO2 based Ferroelectric FieldEffect Transistor
Fig. 1: Schematic representation of the noncentrosymmetric orthorhombic phase for a
certain Si:HfO2 composition.
Fig. 2: Polarization vs. voltage loops for 10
nm Si:HfO2 clearly exhibit ferroelectric nature.
The project aims towards the development of a new fast and
power efficient Non-Volatile Memory concept, the HfO2 based
ferroelectric transistor (FeFET). The FeFET is a long-term contender for an ultra-fast, low-power and Non-Volatile Memory
technology. In these devices the information is stored as a
polarization state of the gate dielectric and can be read nondestructively as a shift of the threshold voltage. The advantage of a FeFET memory compared to the Flash memory is its
faster access times, much lower power consumption at high
data rates, and the easy integration of the device with common CMOS high-k metal gate transistors. The project is covering all aspects from material development, concept proof towards prototype demonstration, including process and capacitor development for device integration, modeling of the material properties, design of cell architecture, and analysis of cell
performance.
During the last years the electrical and material properties of
ferroelectric Si:HfO2 were studied. The polarization curve
shows a remnant polarization of ~25 μC/cm² (Fig. 2). These
ferroelectric properties are caused for a certain Si:HfO2 composition by the appearance of a non-centrosymmetric orthorhombic phase (Fig. 1) under mechanical confinement at the
boundary between the monoclinic and the tetragonal phase.
Varying the dopant content from 0-10 cat% Si is causing the
formation of different HfO2 phases: a mainly monoclinic lattice for pure HfO2, appearance of the orthorhombic phase for
~6 cat% Si and the formation of the tetragonal HfO2 phase for
higher Si contents. Parallel to the geometrical transformation
a change of the ferroelectric properties from paraelectric to
ferroelectric then anti-ferroelectric back to paraelectric is visible (Fig. 2). Implementing this material in a FeFET transistor
is resulting in a memory device which shows a threshold voltage shift of ~1.2 V depending on the polarization state of the
ferroelectric material (Fig. 3) . Extrapolation of the measured
memory window over time indicates that after 10 years still a
window of 0.7 V is visible. Non-volatile memory cell concepts
are being assessed.
In the framework of a project funded by the Free State of
Saxony, the concept is currently integrated into 28 nm CMOS
technology together with GLOBALFOUNDRIES and Fraunhofer
CNT. The first results indicate that the excellent ferroelectric
properties remain after integration and at small feature sizes.
Cooperation: GLOBALFOUNDRIES, Fraunhofer CNT, RWTH
Aachen, Hochschule München, IMEC, University of Helsinki
Fig. 3: Memory window of a FeFET transistor.
Publications: J22, J25, J26, J28, T32, T33
Contact: Dr. Uwe Schröder
7
Si-Nanowire based Devices
The research on silicon nanowire electronic devices at NaMLab addresses the NaMLab core strategy with substantial contributions in the fields of re-configurable electronics and energy efficient devices.
Future electronic devices targeted for the post-CMOS generation are expected to provide added functionality compared to
conventional field-effect transistors (FETs). The investigation
of silicon nanowires is a promising route towards multifunctionality as it takes advantage of the unique combination
of one-dimensional semiconductors with state-of-the-art silicon technology.
At NaMLab we have developed a silicon nanowire based approach (Fig. 1) that enables the dynamic reconfiguration of
the basic FET characteristics by external electric signals (Fig.
2). We have expanded the concept in order to conceive the
world´s first complementary logic circuit fabricated without
the use of dopants. Recently, we have developed a scanning
gate microscopy technique that elucidates the transport
mechanism of our re-configurable FETs and further demonstrates the possibility for non-volatile operation.
In addition to the work on re-configurable nanowire transistors NaMLab is currently developing selective nanowire based
biosensors in cooperation with the Chair of Nanotechnology
at the TU Dresden. A high current nanowire field-effect transistor required for its implementation was developed. Currently, NaMLab is extending its nanowire growth capabilities
for the controlled formation of silicon / germanium nanowire
heterostructures with p- and n- type doping to enable the investigation of high-performance and multi-functional electronic devices.
With respect to re-configurable devices more complex functions like inverters and two re-configurable NOR-NAND gates
will be realized in the next step. These structures will allow to
evaluate the potential of the re-configurable devices for next
generation logic circuits.
Fig. 1: Reconfigurable silicon nanowire transistor invented at NaMLab. One gate programs the device polarity, the other controls
the transistor´s conductance.
Fig. 2: Measured transfer characteristics of
the reconfigurable silicon nanowire transistor
showing programmed p- and n- type transport in the same device.
Cooperation: Lund University, University of Cambridge, NASA
AMES Research Center, CEA, Postech University South Korea,
Universidade de Pisa, HZDR, TU Dresden, IFW, PDI Berlin
Publications: J4, J18, J19, J27, J30, T5, T9, T13, T14, T15,
T22, T23, T24, T30, C5
Contact: Dr. Walter M. Weber
8
Fig. 3: Scanning gate microscopy reveals the
basic transport mechanisms of nanowire
FETs. The mobile gate locally enhances electron tunneling into the nanowire.
Resistive Memory and
Memristor
Fig. 1: Typical material stack forming a
memristor device.
A Memristor is a two terminal device with behavior similar to
that of an ohmic resistor but with variable resistance. In its
simplest form, the Memristor consists of a dielectric material
sandwiched in between two metal electrodes. The current
research on Memristors aims towards the development for
application in fast and non-volatile memory devices, as well
as in reconfigurable and neuromimetic nano-circuits. Indeed,
it combines all aspects of the NaMLab strategy - the development of energy efficient and re-configurable devices based on
dielectric materials.
The central aim of our research is the development of resistive memories – the so called RRAM, which is believed to be
one of the possible candidates for the realization of the universal memory, characterized by very fast access times, nonvolatility, and very low power consumption. In this context, the
digital switching behavior, endurance, retention and reliability
is of utmost relevance. A further interest is the application of
Memristor devices in neuromimetic circuits, exhibiting the
united functionality of logic and memory in one device. Main
focus is the analog switching behavior between several resistive states for elements in a dense arrangement.
Fig. 2: SEM picture of a nanometer-scale
cross-point MIM test structure.
Main part of our activities is so far the deposition of dielectric
thin films, the physical and electrical characterization as well
as the tuning of the resistive switching properties. Different
dielectric materials (i.e. TiO2 and Nb2O5) are explored. In Fig. 1
the schematic of a typical material stack is illustrated. Another central building block is the design of metal-insulatormetal (MIM) test structures on micro- and nanometer scale.
Fig. 2 shows the SEM image of our cross-point MIM test structures, allowing for characterization of real passive arrays. A
further important part of our activities is the development of
electrical characterization techniques for the different devices. C-V, I-V and pulsed measurements are used to analyze
electrical characteristics. In Fig. 3 the switching behavior of
Nb2O5 is shown. After the typically required initial electroforming process bipolar switching was successfully demonstrated
for both, amorphous and crystalline phase. Our results motivate further research into Nb2O5 phase optimization for memory devices.
Further research will be also include the modification of resistive switching layers by ion implantation in close cooperation
with the Helmholtz-Center Dresden-Rossendorf (HZDR).
Cooperation: HZDR, Technische Universität Dresden, FZ Jülich
Fig. 3:
Bipolar switching cycle for amorphous and crystalline Nb2O5. The arrows display the sweeping direction.
Publications: J16, T18, C8, D4
Contact: Dr. Stefan Slesazeck
9
Carbon-based Devices
Nano-crystalline carbon is a versatile metallic electrode material for micro- and nanoelectronic applications. The results of
this research contribute to the core NaMLab goals by providing novel electrodes for high-k dielectric MIM and MIS stacks
as well as innovative electrodes for energy efficient devices in
energy storage batteries.
Carbon has emerged as an active material in micro- and
nanoelectronics devices in the form of graphene layers and
nanotubes. One of the key issues in implementing these materials for future applications is their compatibility with established Si processing technology. NaMLab is investigating
novel nano-crystalline carbon layers as metallic electrode materials in microelectronics in order to integrate carbon nanotubes, graphene and biomolecules into a silicon platform (Fig.
1).
Fig. 1: Raman spectra indicating the degree
of graphitization. G- band peak shift of +20
cm-1 indicates crystallite range order of ~ 2
nm.
The layers are deposited conformally in a silicon compatible
low pressure vapor deposition (LPCVD) tool. The films were
found to be composed of nanometer size sp2 hybridized carbon flakes embedded in an amorphous carbon matrix. Our
investigations showed that the robust scaling behavior of carbon nanowires and vertical vias is superior to that of copper
interconnects (Fig. 2).
The compatibility with SiO2 and Al2O3 dielectrics and the capability of implementing this material as a capacitor electrode was studied systematically. Recently, we proved the
capability to make interface-free Schottky contacts between
n- and p- doped silicon and carbon layers. (Fig. 3) The results
enable the integration of biomolecular species, graphene and
carbon nanotubes onto silicon compatible carbon electrodes.
Current work focuses on the doping of carbon layers (e.g. by
nitrogen) to tune the work function.
Fig. 2: Measured carbon four-point via resistance vs. via diameter.
Cooperation: Lund University, University of Cambridge, NASA
AMES Research Center, CEA, Postech University South Korea,
Universidade de Pisa, HZDR, TU Dresden, IFW, PDI Berlin
Fig. 3: Carbon – SiO2 – p-type Si / metal –
insulator – metal capacitor. Current voltage
characteristics showing Fowler-Nordheim
tunneling at voltages above 5 V.
Publications: J5, J9
Contact: Dr. Walter M. Weber
10
Energy Efficiency Devices
Electrical characterization of photodiodes
Gallium Nitride Materials
and Devices
The III-V compound semiconductor, GaN, with an extremely
wide bandgap and high electron mobility compared to other
semiconductor materials, is almost perfect for devices for
high power operation. A large energy saving potential is seen
for the replacement of Silicon-devices by GaN-devices in
power application of the renewable energy sector and in electric vehicles. Moreover, GaN can be used to fabricate high
electron mobility transistors (HEMTs), in which a buried two
dimensional electron gas of a planar heterostructure between
a source and drain contact can be populated or depleted under the gate contact to switch the device current ON and OFF,
respectively. This particular device type enables much faster
switching compared to standard Si-MOSFET technology, but
causes an even stronger link between GaN material quality
and final device performance. The NaMLab development on
GaN-devices focuses on the technical challenges for building
reliable and cost-efficient products.
Fig. 1: Schematic representation: MISHFET
or MISHEMT structure. MISHEMT = MetalInsulator-Semiconductor- High-Electron- Mobility-Transistor.
A strong cooperation has started in 2010 between NaMLab,
with its device and dielectric material background, and
Freiberger Compound Materials as potential GaN substrate
supplier. On the one hand NaMLab supports and accelerates
the GaN substrate development at FCM by giving fast feedback from device performance; on the other hand NaMLab
will study new device concepts with an additional high-k dielectric underneath the gate (MISHEMT) or later with 3D geometry. A widespread network from this core cell to other research institutes and industrial partners builds up and is envisioned for the future.
Several key tools for GaN device technology have been purchased in already approved subprojects. For example, a Hydrogen-Vapor-Pressure-Epitaxy (HVPE) system and a Molecular Beam Epitaxy (MBE) system with in-situ high-k deposition
will be available for versatile substrate and heterostructure
growth. Power devices can be electrically characterized with a
suitable high-voltage probe station.
Fig. 2: Testchip layout (Sample size 2.6 x 2.6
cm2). Different test-structures enable the
optimization of process steps and the overall
device integration/performance.
NaMLab has defined a front-up process flow for planar
MISHEMT devices starting with a high-k coated GaN heterostructure (Fig. 1). The flow contains four lithographic steps
and all process steps are available at NaMLab or the Institute
of Semiconductors and Microsystems of TU Dresden (Fig. 2
and 3). Having access to flexible, in-house GaN heterostructure growth and external high quality substrate material give
excellent preconditions for a detailed evaluation of the link
between device performance and material properties.
Cooperation: Technische Universität Dresden (IHM),
Freiberger Compound Materials, Fraunhofer IAF, Ferdinand
Braun Institute, Universität Ulm (IOE), Technische Universität
Bergakademie Freiberg (Physics), Azzurro, Aixtron
Contact: Dr. Andre Wachowiak
12
Fig. 3: I– V characteristics of test structures
for the ohmic metal contacts reveal promising results of low contact resistance to the
two dimensional electron gas.
Dye-based Solar Cells
Dye-sensitized solar cells (DSSC) are one of the most promising candidate of third generation solar cells. The main advantages are the low-cost production process at low temperatures and the use of non-toxic materials. This concept has a
high potential to significantly reduce the costs for solar energy generation. However, the efficiency of today’s cells is still
too low to compete with conventional silicon solar cells.
Fig. 1: TiO2 surface conditioning with ALD.
Fig. 2: Raman measurement on a stack of
ALD-TiO2 on top of a rutile TiO2 substrate.
The TiO2 phase depends on the thickness of
the intermediate Al2O3 buffer (1 cycle =
0.1 nm).
The key process within the DSSC is the charge separation between the dye and the porous TiO2 electrode (see Fig. 1). The
electrode is about 20 µm thick and consists of TiO2 nanoparticles smaller than 50 nm. To achieve highest cell efficiencies, the surface of the nano-particles needs to be well controlled. This project focuses on TiO2 surface conditioning using the atomic layer deposition (ALD) technique. ALD is a
powerful method for homogeneous film deposition onto extremely large inner surfaces due to its self-limiting growth.
The ALD layer on top of the as-deposited TiO2 nano-particles
allows defining a uniform high-quality surface. This surface
will be optimized for the solar cell performance, the key parameters are: phase (anatase/rutile), stoichiometry, impurities, crystallinity (amorphous/crystalline) and surface roughness.
The principle of TiO2 surface phase conditioning was demonstrated using a planar TiO2 substrate in the pure rutile phase
(Fig. 2). The best photovoltaic results were achieved with anatase TiO2 electrodes. Pure rutile TiO2 represents the “worst
case” crystal structure. On top of this substrate a thin (~15
nm) TiO2 layer was deposited with the target phase being
anatase. In a straight-forward deposition the structure of the
substrate acts as seed crystal for the further growth, i.e. the
top layer also grows in the rutile phase. Different strategies
were evaluated to overcome this undesired interaction with
the substrate. Most successful was the introduction of an ultra-thin (~0.5 nm) Al2O3 buffer layer. This interface enables
the growth in anatase phase, which is independent of the substrate. To demonstrate the benefit of the surface conditioning
complete devices were assembled and photo-electrically
characterized. The additional ALD-TiO2 layer improves the incident photon conversion efficiency (IPCE) up to 10 times.
Cooperation: Technische Universität Dresden (IHM), FILK, FSU
Jena
Publications: C10
Contact: Dr. Ingo Dirnstorfer
13
Passivation Layers for
Solar Cells
NaMLab investigates different strategies for the Al2O3 deposition including the Physical Vapor Deposition (PVD) and the
Atomic Layer Deposition (ALD) using H2O and O3 as oxidizer.
Furthermore, different doping strategies were evaluated to
further optimize the passivation layers in terms of recombination rate and high-temperature stability. NaMLab focus on
photo-carrier lifetime (MDP) and electrical (CV) measurements to characterize the passivation layers. The applied
electrical methodology is very similar to that applied in microelectronics e.g. for MOSFET structures. This allows the use
of a broad expertise and specialized equipment, which is set
up for microelectronic research at NaMLab. The excellent passivation of Al2O3 could be linked to a combination of a low
density of interface traps (Dit) and high density of negative
fixed charges (Qfix). The latter generate an electrical field to
repel electrons from the surface.
Systematical Ti and Si doping of Al2O3 passivation layers is a
relatively new research field. Doping in the percent-range influences the chemical coordination within the crystal and creates new defects types, which potentially carry the targeted
negative charge. It could be shown that the Al2O3 passivation
improves with 3 at% Si-doping, resulting in a slightly enhanced effective carrier lifetime (Fig. 2). Al2O3 passivation
layers were also doped with Ti. However, no improvement in
the effective carrier lifetime was observed for this material.
The process window for the doping concentration was limited
by 10 at% and 0.5 at% for Si and Ti, respectively. The electrical evaluation of these critical concentrations reveals the formation of interface traps at the silicon surface. These traps
act as recombination centre for photo-generated carriers and
significantly reduce the effective carrier lifetime. The understanding of the doping limitations is a key input for the ongoing investigations on doped Al2O3 passivation layers.
Above measurements were performed on double side ALD
coated Czochralski type Si-wafers. Currently, these processes
are repeated on Flow Zone substrates where charge carrier
lifetimes of more than 5ms are achieved for wafers passivated with 10nm undoped Al2O3 (Fig. 3).
Fig. 1: PERC (Passivated Emitter and Rear
Cell) solar cell concept presented by the ISFH
(Adopted from J. Schmidt).
Fig. 2: Effective carrier lifetime measured
on silicon wafers passivated with 20 nm Sidoped Al2O3. A moderate Si-doping (3 at%)
slightly improves the passivation performance.
10000
Effective Lifetime τ eff (μs)
Future generations of high-efficiency solar cells rely on excellent passivation of the silicon back surface to ensure minimal
surface recombination losses. Considerable R&D effort is currently being pursued to develop an alternative to the back
surface field, which is today’s industrial standard for silicon
solar cells. Recently, it was shown that Al2O3 films synthesized by ALD reached an excellent level of surface passivation. On high-quality float-zone wafers, excellent minority carrier lifetimes were demonstrated, corresponding to very low
surface recombination rates of less than 10 cm/s.
1000
100
250
Cooperation: Technische Universität Dresden (IHM), FhG
IKTS, FhG CNT
Publications: T21, T26, C4, C9, D1
Contact: Dr. Ingo Dirnstorfer
14
350
450
Temperature of N2 anneal (°C)
Fig. 3: Effective carrier lifetime measured on
flow zone wafers passivated with 30 nm
undoped Al2O3.
Si-Nanowire Anodes for
Li-Ion Batteries
Novel electrode materials for charge storage batteries are
being developed at NaMLab. They contribute to the core aims
for energy efficient devices at NaMLab.
Fig. 1: SEM images of silicon nanowires.
Dense growth of nanowires with 20 nm diameters.
NaMLab has developed a stable and cyclable anode assembly
for lithium-ion batteries by the integration of silicon
nanowires. The high theoretical charge capacity (~4200
mAh/g) of Si, comparatively low discharge potential and
availability have made silicon a desirable battery anode material. However, induced stress upon lithiation has led to the
pulverization of bulk and layered silicon making it inappropriate for use in batteries. Nanostructured silicon has the property to relax the strain built during charge / discharge cycles.
Among various nanostructure silicon embodiments, silicon
nanowires are currently the scope of extensive international
research, since their relaxation properties are good and sufficient electric conductance to the current collector is being
provided.
NaMLab developed scalable bottom-up assembly strategies
to build cyclable anodes. These encompass the grown silicon
nanowires via chemical vapor deposition (Fig. 1) and their
integration into current collectors via an innovative electroless nickel plating (Fig. 2). The developed method allows
great flexibility with various substrates and nanowires in both
short and long term testing. After testing a variety of potential
substrates, copper was found to provide good electrical conductance and minimal electrochemical side reactions with
the electrolyte and lithium. Testing of silicon nanowires attached to the copper mesh also yielded promising results
over 120 cycles. Lithiation (0.0 V) and de-lithiation (0.33 V
and 0.46 V) of the nanowire anodes were clear and reproducible (Fig. 3).
Fig. 2: SEM image of silicon nanowires integrates onto copper collectors via bottom up
assembly with electroless nickel plating.
However, before silicon nanowire anodes become integrated
into a commercial product, there are still major challenges to
overcome. These include optimizing growth conditions, understanding morphological changes during lithiation and improving cycling performance. Successful implementation of silicon
nanowire anode assemblies is expected to increase charge
capacity, specific energy density, lifetime, reliability and
safety. This would strongly contribute to electromobility with
higher reach distances, enhanced energy storage within
smart-grid matrices and longer lasting medical and portable
electronic devices.
Cooperation: FhG IWS, FhG IKTS, IFW Dresden, Technische
Universität Dresden
Fig. 3:
Cyclic voltamogram of silicon
nanowires attached to Cu mesh through electroless cycles 4-128, scan rate of 1mV/s,
with electrolyte LiClO4 PC.
Publications: C3
Contact: Dr. Walter M. Weber
15
Photodiodes
One target of the NaMLab photodiode project is the development of new photodiode structures, which enable to adjust
the functionality of the diode in a sensor system post manufacturing. Hence, the overall system, e.g. a color sensor, can
be re-configured only by software changes related to the data
processing and not by the pricy photodiode technology.
A testchip vehicle with multiple layout variations of photodiodes was designed. Fully processed chips of the tunable color
sensor have been characterized in our optical laboratory. The
new principle is based on the capability to tune the photodiode depletion area from very shallow, surface-near extension
for small reverse bias voltage to very deep areas for large reverse bias; basically over the entire absorption depth of visible light. An additional, build-in competing sink for diffusion
charge carriers ensures, that almost exclusively charge carriers generated within the depletion area contribute to the
photocurrent. Hence, this photodiode is mainly blue sensitive
for small reverse bias. In contrast, charge carriers generated
by the full spectrum, but especially of the red region, contribute to the photocurrent for large reverse voltage. Fig. 2 shows
the wavelength dependent sensitivity of the photodiode as
measured under different reverse voltages.
The color-sensing performance of the device corresponds to
the response of a hypothetical, emulated human eye with
best-fit receptor functions. Fig. 3 presents a very good example of fitted receptor functions (dashed) from a linear combination of the sensitivity curves compared to the real receptor
functions (solid) of the human eye. In sensor operation the
true color is calculated from the ratios of the three response
values e.g. blue=none, green=red=high results in yellow. One
major advantage of the novel device stems from the adaptive
adjustment on different tasks by simple software changes of
the data processing, instead of costly technology development e.g. for filter layers.
Fig. 1: Modular demonstrator for proving
functionality of sensor systems. Left: Zoom
on photodiode element. Right: Electronic
circuit in shielded metal box with USB connection to PC.
Fig. 2: Series of sensitivity curves for different operational reverse voltage of photodiode. Blue curves: without competing sink;
red curves: with active competing sink.
At last, an automated measurement environment for the photodiode was build-up out of commercial electronic modules.
Control measurements with this fully functional sensor prototype should reveal the necessary information for the future
design of a System-On-Chip Sensor. A photograph of the sensor system is shown in Fig. 1.
Cooperation: Technische Universität Dresden , Infineon Technologies Dresden, X-FAB Semiconductor Foundries
Publications: D2, I1
Contact: Dr. Andre Wachowiak
16
Fig. 3:
Example of best fit emulation
(dashed) of true eye receptor functions
(solid) from linear combination of series of
sensitivity curves shown in previous figure.
Competences
300mm electrical probe station
Electrical Characterisation
The characterization of materials, devices and circuits is unthinkable without electrical measurement techniques and
methods. NaMLab has a broad spectrum of electrical measurement methods for device analysis (Fig. 1). This includes
capacity measurements, such as C(U), C(T) and C(f), current
measurements in the femtoampere range for temperatures
between 5K and 450K and voltages up to 3000V. Samples
can be analyzed by probe card measurements or package
level testing. In addition, carrier lifetime measurements are
available on substrates with Microwave Detected Photoconductivity.
The established methods at NaMLab include:
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Analytical measurements of single memory cells for the
determination of lifetime, storage and deletion windows as well as switch time.
Determination of transistor and capacitor characteristics.
Analysis of Polarization behavior for ferro-dielectrics
Impedance spectroscopy
Measurement of charge carrier mobility with Hall and
split-C(V) on in-organic and organic semiconductors.
Determination of layer resistance.
Scanning spreading resistance and Scanning Gate Microscopy
Conductive atomic force microscopy.
Reliability measurements of dielectric and transistors,
starting with time dependent dielectric breakdown and
stress induced leakage current all the way to bias temperature instability, dielectric relaxation and hot carrier
injection.
Charge pumping and charge trapping analysis.
Cyclovoltametry.
The available methods can be applied to wafers up to 300
mm or to package mounted devices.
Fig. 1:
Electrical characterization of test
structures on a 300 mm wafer, in a semiautomatic probe station.
Fig. 2: Schematic of the SGM setup. The
NiSi2 electrodes act as the source and drain.
The Si substrate is the back gate, and the
conductive AFM Tip is the scanning top gate.
Two typical case studies for the leverage of our technique are
highlighted:
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A Scanning Spreading Resistance Microscopy Analysis
of a silicon solar cell with a highly doped selective emitter. The locally enhanced doping is clearly measurable
by SSRM (Fig. 3) .
A Scanning Gate Microscopy Analysis (SGM — Fig. 2)
together with an IV measurement of a silicon nano wire
Schottky barrier FET. While the SGM measurement depicts the location of the Schottky barrier, the IV measurement reveals the gate controllability of the device
(see also page 8).
Publications: J1, J12, J20, J23, J24, T1, T7, T10, T20, T28,
T29, C6, P1
Contact: Dr. Stefan Slesazeck
18
Fig. 3: Scanning Spreading Resistance Microscopy showing a 2D doping profile of Laser Doped Selective Emitter Structures in
Solar Cells
Physical Characterisation
Fig. 1: HRSEM picture of a single nanowire
transistor.
Fig. 2: C-AFM measurement on ZrSrO3:
Grain boundaries visible on the topography
map on the left hand side clearly correlate
with dark areas on the current map on the
right.
Fig. 3: X-ray diffraction in grazing incidence
setup on a series of SrZrO films with varying
angle of incidence provides information on
depth resolved layer structure.
NaMLab engages in state-of-the-art research in the field of
materials development for nanoscale application relevant to
the semiconductor industry in strong co-operation with its industry partners as well as with other laboratories and universities throughout Germany and Europe to foster strong scientific ties with other universities for progress in industryoriented as well as basic research. The physical characterization focus at NaMLab can be summarized as follows: The
available high-resolution scanning electron microscope
(HRSEM) is capable of providing high magnification images
down to 10 nm resolution (Fig. 1). Besides top-view images,
cross-sectional SEM imaging showing the entire layer architecture (in case of multilayer thin films structures) can be imaged easily by a switch of sample holders. Furthermore, the
SEM in equipped with an EDX (energy dispersive analysis)
gun. A very accurate and trustworthy chemical composition
determination of the samples is possible covering almost the
entire periodic table. Another equally fascinating feature of
HRSEM is the high resolution electron beam lithography (EBeam) for developing photoresist. With the HRSEM a programmable e-beam scanning of the samples in the 100 nm
accuracy regime is possible.
The atomic force microscope (AFM) is equipped with the
nanoscope user interface for measurement and data analysis. Resolution in the order of 10 nm in the scanning direction
and down to 1 nm perpendicular to the scanning direction is
reported routinely. Besides regular tapping mode and contact
mode AFM for topography imaging with Si tips or diamond
coated Si tips, conducting AFM (c-AFM) and surface spreading
resistance microscopy (SSRM) allows local I-V curve measurements or correlation of electrical properties to sample microstructure. Current resolution in the order of a few pA is detectable with the TUNA amplifier (Fig. 2). SSRM module on the
other hand allows current magnification in the mA range
along with very good spatial correlation.
X-Ray Diffraction (XRD): The multifunctional tool allows for Xray diffraction in the Bragg-Brentano set-up, Grazing incidence
diffraction and X-ray reflectivity in the same apparatus. A
quick change of source geometry permits also pole figure
measurements for in-plane texture information. The tool with
its newly introduced snap-lock and DaVinci features allows
easy change and recognition of parameters in the primary
and secondary beam paths. A line detector with a line width
of 14 mm or 200 parallel Si strips makes the measurement
accordingly faster in comparison to a single scintillation detector without compromising resolution (see Fig. 3).
Contact: Dr. Andre Wachowiak
19
Device Reliability
Today, scaling of microelectronic devices is tightly linked to
the availability of mature and reliable integration of new materials. Those materials applied on a nanometer scale act as
gate insulator, high conductivity metals, stress or strain layers
or memory dielectrics. Nevertheless, beside the increasing
complexity of devices any compromise in reliability is not acceptable. Therefore, NaMLab performs stress measurements
at high performance transistors with elevated temperatures
and voltages to analyze their stability behavior. Especially for
high dielectric constant gate insulators the fundamental understanding of bias temperature instability, hot carrier injection, stress induced leakage currents, and time dependent
breakdown are of major interest. Reliability investigation of
ZrO2/Al2O3/ZrO2 structures for DRAM capacitors were performed to correlate the lifetime of the sandwich to the crystal
structure of the zirconium.
Fig. 1: SRAM setup and important stress
mechanism under operation (HCI: hot carrier
injection, P/NBTI: positive and negative bias
temperature instability).
Though, it is widely accepted to live with variations of device
parameter over time, the lethal change of device parameter
to circuit operation is still an open question. For example,
even if some transistors exhibit an increased power consumption after hundreds of operation hours the functionality of the
entire chip could still be ensured. NaMLab therefore focuses
on the change of circuit performance parameters caused by
the single device degradation. Based on the investigations,
models for life time prediction will be developed, for instance
for static-random-access-memory (SRAM) cells (Fig.1).
Throughout the SRAM investigations defined stress conditions
to selected transistors within the cell are applied. The measurement setup allows the observation of performance degradation of a single transistor 10 µs after stress. This way relaxation effects can be eliminated or analyzed separately. The
degradation of the nFET turned out to be most significant for
SRAM lifetime. Hot carrier injection leads to a high threshold
voltage degradation and reduced current through the nFET.
But it occurs only very short time during operation. The positive bias temperature instability (PBTI) has come up the first
priority reliability issue. A model for the threshold voltage drift
due to PBTI under hold conditions was developed (Fig. 2) and
correlated to the measured SRAM circuit parameters (Fig. 3).
Fig. 2: Model and measurement of the
threshold voltage shift of the SRAM nFET
after PBTI stress.
Cooperation: Fraunhofer IIS EAS, GLOBALFOUNDRIES
Publications: J6, T16, C11, D3
Contact: Dr. Stefan Slesazeck
20
Fig. 3: Measured butterfly curve before and
after PBTI stress under read conditions
(supply voltage at wordline and bitline).
Optical Characterisation
Fig. 1: Set-up for Low-temperature Photoluminescence measurements
Optical characterization is a powerful method for understanding the properties of semiconductor materials and devices.
On the one hand, this method is applied to determine defect
types and their energy levels in semiconductor materials and
interfaces. On the other hand, this method is applied to evaluate the functionality and performance of photoactive devices.
The optical laboratory at NamLab is equipped with highresolution spectrometers and sensitive detectors for the UV to
NIR range. For excitation different laser sources from UV (325
nm) to VIS are available as well as broad band high-power
light sources (Xenon lamps). This allows measuring the photoluminescence and excitation spectra of a large number of
semiconductors. In addition, the spectral response of photodiodes and solar cells can be investigated.
The established methods at NaMLab include:
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Fig. 2: Photoluminescence spectra of GaN.
Low-temperature Photoluminescence (15 – 300 K) for
the UV – NIR range (325nm – 1700 nm) with UV (325
nm) or VIS laser excitation (Fig. 1-3)
Low-temperature Excitation spectroscopy (PLE) using a
high power Xe-source for the UV – VIS range
Photodiode spectral response with calibrated reference
sensor
µRaman with different excitation lasers (spatial resolution: 1 µm)
External Quantum Efficiency setup including bias illumination
µ-spot IR Ellipsometry
UV-VIS Ellipsometry as well as
VIS-NIR Reflectometry.
Two typical case studies for the leverage of the techniques
are highlighted:
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In the last year NaMLab has developed a new principle
for color detection with special photodiodes. The spectral response of this novel photodiode technology has
been measured and compared to calibrated commercial sensors.
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Porous TiO2 electrodes for dye-sensitized solar cells
could be significantly improved by adding a thin ALDlayer with well defined properties. The spatial resolved
µRaman measurement applied to TiO2 cross-sections
confirmed that the ALD process homogeneously covers
the 20 µm thick electrode from top to bottom side
Publications: C7
Fig. 3: Set-up for Low-temperature Photoluminescence measurements
Contact: Dr. Ingo Dirnstorfer
21
Facts & Figures
Budget (Financing)
3000
Budget in TEUR
2500
2000
Others
Contract research
Public funding
Basic financial support
1500
1000
500
0
2006 2007 2008 2009 2010 2011
Fig. 1: Annual Budgets
Budget in TEUR
Budget (Investment)
5000
2000
1000
0
2006 2007 2008 2009 2010 2011
Fig. 2: Investment Budgets
Employee Development
35
Employees
30
Non-Scientific
Scientific
25
20
15
10
5
0
NaMLab in Numbers
2006 2007 2008 2009 2010 2011
Annual Budget
The annual budget over the last 5 years shows the expected
increase rate for a newly founded institute achieving full operation within 5 to 6 years. 2010 was still driven by the rampup of the institute. Research revenue nearly doubled from
2009 to 2010. 2011 being the first year with stable revenue
demonstrates the successful start of operation. About 37% in
2010 and 40% in 2011 of the annual budget are related to
the basic financial funding of the Free State of Saxony. Project funding by the European Commission, the Germany Federal Ministry of Education and Research, the German Federal
Ministry of Economics and Technology, and the Saxony State
Ministry of Science and Arts reached about 1.5 Mio. Euro in
2010 and about 1.7 Mio in 2011. Contract research was stable from 2009 to 2011. In parallel the investment in new
equipment was significant in 2010 and 2011.
Investment Budget
The clean room facilities at the NaMLab conform to the highest standards. 250 m² (DIN ISO 5) and 50 m² (DIN ISO 4) are
available for experimental work. NaMLab runs seven deposition technologies based on different concepts and nine processing tools. Two state-of-the-art electrical characterization
labs for material and device characterization are equipment
with 200 and 300 mm probe stations. For optical and physical characterization labs are available. 2010 NaMLab invested mainly in a new electrical characterization set-up and
a lifetime measurement system financed by a project of the
Federal Ministry of Education and Research and a project of
the Saxony State Ministry of Higher Education, Research and
the Arts. 2011 had significant investment into deposition
technology, a new PVD system, an ALD deposition tool and
two clustertools. In addition, an XRD measurement system
and a probe station had been installed. The research equipment had been financed by a project co-financed by the
Saxony State Ministry of Higher Education, Research and the
Arts and the European Commission (ERDF), a project of the
Business Activities Support Programs co-financed of the Free
State of Saxony and the German Federal Government and the
basic financial funding of the Free State of Saxony.
Human Resource Development
Since the start in 2006 the NaMLab staff has grown continuously. In 2010 number of employee increased by about 20%.
2011 showed a stable employment with 34 staff members.
This includes 3 employees for administration, 3 employees
for technical support, and 3 student assistance. The number
of PhD students increased to 14. The stable employment in
numbers in 2011 is masking the changes behind. Young talents joint NaMLab and some of the experienced employees
left NaMLab overall in the normal range of a research institute.
Fig. 3: Human Resource Development
Contact: Dr. Alexander Ruf
23
Cooperations
NaMLab uses a broad cooperation network in order to close
the experimental chain. NaMLab has extensive cooperations
with leading international, European and German research
organizations and industrial partners. In particular, it has a
very close cooperation with the Institute of Semiconductor &
Microsystems Technologies (IHM) of the Technical University
Dresden, the Fraunhofer Society (especially with the Fraunhofer Center Nanoelectronic Materials (CNT)), the Leibniz Institute for Solid State and Material Research (IFW Dresden)
and the Helmholtz-Center Dresden-Rossendorf (HZDR). Via
the IHM facilities NaMLab has access to further 700 m² clean
room infrastructure (DIN ISO 4 - ISO 7 standard) in two buildings on the campus of the TU Dresden.
Contact: Dr. Uwe Schröder
24
Projects
Project overview of approved research projects
In 2010/2011, NaMLab participated in research projects
funded by the German Federal Ministry of Education and Research (BMBF), the German Federal Ministry of Economics
and Technology (BMWi), the Saxony State Ministry of Higher
Education, Research and the Arts (SMWK) as well as by the
European Commission (EU).
Kondor
Materialforschung und Charakterisierung für Speicheranwendungen
BMBF
MegaEpos
Metal-Gate Elektroden und epitaktische Oxide als
Gate Stacks für zukünftige CMOS-Logik und Speichergenerationen
GOSSAMER
Gigascaled Oriented Solid State Flash Memory for
Europe
BMBF
Merlin
ALD Abscheidetechnik für neue Materialien und
wenige Atomlagen dicke Schichtsysteme
Cool Silicon
Technologien für energieeffiziente Computing Platformen
Multifunktionale Speicherkonzepte
Multifunktionale Speicherkonzepte
SMWK
Hansel
Herstellung und Charakterisierung von Niobpentoxid Schichten mit schaltbarem elektrischen Widerstand
DFG
Heiko
Entwicklung zukünftiger High-k Gate-Dielektrik
Transistoren einschließlich einer Machbarkeitsstudie für HfO-basierte ferroelektrische Speicher
SMWK
Farbstoffsolarzellen
Entwicklung und Optimierung von Halbleiterschichten und Farbstoffen für Farbstoffzellen
BMWi/
AiF
Enhance
European Research Training Network of “New Materials: Innovative concepts for Fabrication“
EU
GaNFET
Entwicklung einer wettbewerbsfähigen GaNTechnologie
SMWK
Diffussionsbarrieren
Herstellung von Gasdiffusionsbarrieren für organische Leuchtdioden oder Solarzellen
BMWi/
AiF
S-PAC
Automatisierte modulare Kompaktanlage zum Laserabtragen von Si-basierten Solarzellen
Contact: Dr. Alexander Ruf
SMWK
25
EU
BMBF
BMBF
NaMLab goes public
NaMLab promotes the continuous exchange and dialogue
with business partners, customers, students as well as the
general public. NaMLab supports the very close contact between research, industry and education. In 2010 and 2011
NaMLab attended various international events, conferences &
meetings, and trade fairs all around the world.
NaMLab participation at
conferences & meetings in 2010/ 2011:
DPG Spring Meeting 2010
March 21-26, 2010, Dresden (Germany)
217th Meeting of the Electrochemical Society
April 25-30, 2010, Vancouver (Canada)
5th Fraunhofer-IMS Workshop „CMOS Imaging—Low Light
Imaging“
May 04-05, 2010, Duisburg (Germany)
16th Workshop on Dielectrics in Microelectronics
June 28-30, 2010, Bratislava (Slovakia)
8th International Nanotechnology Symposium
July 6-7, 2010, Dresden (Germany)
25th European Photovoltaic Solar Energy Conference & Exhibition (PVSEC)
September 05-08, 2010, Valencia (Spain)
40th European Solid-State Device Research September 1317, 2010, Sevilla (Spain)
BALTIC Atomic Layer Deposition Conference
September 16-17, 2010, Hamburg (Germany)
DPG Spring Meeting 2011
March 13-18, 2011, Dresden (Germany)
MRS Spring Meeting & Exhibit
April 25-29, 2011, San Fransisco (USA)
219th Meeting of the Electrochemical Society
May 1-6, 2011, Montreal (Canada)
7th Chemnitzer Seminar for Nanotechnology and Nanoreliability
May 24, 2011, Chemnitz (Germany)
17th Conference on „Insulating Films on Semiconductors“
June 21-24, 2011, Grenoble (France)
11th International Conference on Atomic Layer Deposition
June 26-29, 2011, Boston (USA)
26th European Photovoltaic Solar Energy Conference & Exhibition
September 05-09, 2011, Hamburg (Germany)
41th European Solid-State Device Research
September 12-16, 2011, Helsinki (Finland)
VII. Internation Conference on Microelectronics, Optoelectronics and Nanoelectronics
November 28-30, 2011, Venice (Italy)
26
NaMLab goes public
Childrens Day
In 2010 and 2011, NaMLab continued its attempts to make
scientific and research work more accessible for the public in
general. In particular, it kept its efforts to inspire young people to study science or engineering. NaMLab took part in
many joined activities like the “Long Night of Science” in
2010 and 2011, the summer school “Dresdner Microelectronics Academy”, and the “University Day” of the Technical University Dresden in 2011. NaMLab organized a “Children Day”
for primary-school pupil in the 2nd class. The children gained
insight in the work of researchers under clean room condition.
In 2011, the researchers of the NaMLab participated as supervisor of the work experience in 7th and 8th school class of
the Martin-Andersen-Nexö secondary school Dresden.
SEMICON 2009/2010/2011 in Dresden
The largest and most important semiconductor event in
Europe, the SEMICON, took place in the capital of Saxony. Together with 350 exhibitors from 20 countries NaMLab presented its manifold activities in development of material solutions for tomorrow’s electronic devices. The researchers of
NaMLab showed new innovations, e.g. in the fields of micro &
nanowire devices, energy harvesting, and non-volatile memories.
Long Night of Science, 2010/2011
SEMICON
Long Night of Science
In 2010, 32 research institutes, companies, and four universities opened their laboratories, lecture halls and offered a
comprehensive program for the 8th Long Night of Science according to the motto “Forsch, Forscher, Am Forschen” in Dresden. At NaMLab the people got acquainted with material research for future electronics. The program offered visiting
tours through the laboratories and presented in experimental
shows the characterization methods for nano-scaled electronic devices and measurements with modern microscopes.
In the exhibition “From the raw material to the micro chip”
NaMLab presented scientific research in micro– and
nanoelectronics. Also in 2011, NaMLab participates with lab
tours and experimental shows at the 9th Long Night of Science according to this year motto “Weck den Forscher in dir”.
400 people uses again the opportunity to gain insight in the
work at NaMLab.
Contact: Prof. Dr.-Ing. Thomas Mikolajick
27
NaMLab goes public
Novel High-k Application Workshop Dresden 2010/2011
NaMLab invited to the Novel High-k Application Workshops in
winter 2010 and 2011 to Dresden. New challenges offered
by the application of high-k dielectric materials in micro– and
nanoelectronics have been discussed by more than 70 participants from industry, research institutes and universities. NaMLab created with the workshop a stimulating European platform for application-oriented scientist to exchange ideas and
discuss latest experimental results on MIM-capacitors, process technology, leakage & reliability as well as characterization of high-k dielectrics integrated in silicon based micro–
and nanoelectronics.
Novel High k Applications Workshop
Working Group on Materials for Nonvolatile Memories
The working group „Materials for Nonvolatile Memories“ exists since 2005. With the move of Prof. Thomas Mikolajick
from TU Bergakademie Freiberg to NaMLab, the organization
of this working group moved to the responsibility of NaMLab.
In 2010 a meeting was hosted and organized by X-FAB Semiconductor Foundries in Dresden. In 2011 the meeting was
hosted by the Leibnitz Institute of high performance microelectronics (IHP) in Frankfurt/Oder. The upcoming meeting in
April 2012 will be hosted by TU Munich.
Visit of the Saxonian Minister for Higher Education, Research
and the Art at NaMLab, 10. November 2011
The project release for the GaN infrastructure project was
handed over by the Saxonian Minister for Higher Education,
Research and the Arts Prof. von Schorlemer. For the research
on the semiconductor material Galliumnitride NaMLab will
be funded by the SMWK with a funding volume of 1.9 Mio.
Euro. The research on the development of future electronic
devices including GaN will be strongly interlocked with the
substrate development. In a strong cooperation with the Freiberger Compound Materials GmbH NaMLab will establish a
research laboratory for Galliumnitride wafers in Freiberg.
Visit of the Saxonian Minister for Higher Education, Research and the Arts:
Prof. von Schorlemer
12th AVS-ALD conference 2012 in Dresden
NaMLab and nanoGUNE (San Sebastian, Spain) will be the cochairs for the ALD conference 2012 of the American Vacuum
Society in Dresden on June 17-20, 2012. The American Vacuum Society (AVS) Topical Conference will be a three-day meeting dedicated to the science and technology of atomic layer
deposition (ALD) of thin films.
American Vacuum Society —
ALD conference 2012 in Dresden
Contact: Prof. Dr.-Ing. Thomas Mikolajick
28
NaMLab in the Press
Contact: Prof. Dr.-Ing. Thomas Mikolajick
29
Publications 2010/2011
Journal Papers - 2010/2011
J1
K. Bernert, C. Oestreich, J. Bollmann, and T. Mikolajick
The influence of bottom oxide thickness on the extraction of the trap energy in SONOS structure
Appl. Phys. A 100, 249 (2010)
J2
J. Heitmann and T. Mikolajick
Nanocrystalline materials: Optimization of thin film properties
ECS Trans. 28, 451 (2010)
J3
G. Jeggert, A. Kersch, W. Weinreich, U. Schröder, and P. Lugli
Modeling of leakage currents in high-k dielectrics: Three-dimensional approach via kinetic Monte Carlo Simulation
Appl. Phys. Lett. 96, 062113 (2010)
J4
C. Chéze, L. Geelhaar, O. Brandt, W. M. Weber, H. Riechert, S. Münch, R. Rothemund, S. Reitzenstein, A. Forschel,
T. Kehagias, P. Komninou, G. P. Dimitrakopolous, and T. Karakostas
Direct comparison of catalyst-free and catalyst-induced GaN nanowires
Nano Res. 3, 528 (2010)
A. P. Graham, G. Schindler, G. S. Duesberg, T. Lutz, and W. M. Weber
An investigation of the electrical properties of pyrolytic carbon in reduced dimensions; vias and wires
J. Appl. Phys. 107, 114316 (2010)
J5
J6
D. Zhou, U. Schröder, J. Xu, J. Heitmann, G. Jegert, W. Weinreich, M. Kerber, S. Knebel, E. Erben, and T. Mikolajick
Reliability of Al2O3-doped ZrO2 high-k dielectrics in 3-dimensional stacked metal-insulator-metal capacitor
J. Appl. Phys. 108, 124104 (2010)
J7
S. Schmelzer, D. Bräuhaus, U. Böttger, S. Hoffmann-Eifert, P. Meuffels, R. Waser, P. Reinig, L. Oberbeck, and U:
Schröder
SrTiO3 thin film capacitors on silicon substrates free from interfacial passive layers
Appl. Phys. Lett. 97, 132907 (2010)
J. Paul, V. Beyer, M. Czernohorsky, M. F. Beug, K. Biedermann, M. Mildner, P. Michalowski, E. Schütze, T. Melde, S.
Wege, R. Knöfler, and T. Mikolajick
Improved high-temperature etch processing of high-k metal gate stacks in scaled TANOS memory devices
Microelectron. Eng. 87, 1629 (2010)
A. P. Graham, K. Richter, T. Jay, W. M. Weber, S. Knebel, U. Schröder, and T. Mikolajick
An investigation of the electrical properties of MIS capacitors with pyrolytic carbon electrodes
J. Appl. Phys. 108, 104508 (2010)
J8
J9
J10
M. F. Beug, T. Melde, M. Czernohorsky, R. Hoffmann, J. Paul, R. Knöfler, and A. T. Tilke
Analysis of TANOS memory cells with sealing oxide containing blocking dielectric
IEEE T Electron. Dev. 57, 1590 (2010)
J11
D. Martin, M. Grube, W. Weinreich, J. Müller, L. Wilde, E. Erben, W. M. Weber, U. Schröder, T. Mikolajick, and H.
Riechert
Macroscopic and microscopic electrical characterization of high-k ZrO2 and ZrO2/Al2O3/ZrO2 metal-insulator-metal
structures
J. Vac. Sci. Technol. B 29, 01AC02 (2011)
G. Roll, S. Jakschik, M. Goldbach, A. Wochowiak, T. Mikolajick, and L. Frey
Analysis of the effect of germanium preamorphisation on interface defects and leakage current for high-k metaloxide-semiconductor field-effect transistors
J. Vac. Sci. Technol. B 29, 01AA05 (2011)
A. Krause, W. M. Weber, A. Jahn, K. Richter, D. Pohl, B. Rellinghaus, U. Schröder, J. Heitmann, and T. Mikolajick
Evaluation of electrical and physical properties of thin calcium titanate high-k insulators for capacitor applications
J. Vac. Sci. Technol. B 29, 01AC07 (2011)
J12
J13
J14
M. Grube, D. Martin, W. M. Weber, T. Mikolajick, O. Bierwagen, L. Geelhaar, and H. Richert
The applicability of molecular beam deposition for the growth of high-k oxides
J. Vac. Sci. Technol. B 29, 01AC05 (2011)
Publications 2010/2011
Journal Papers - 2010/2011
J15 D. Martin, M. Grube, P. Rienig, L. Oberbeck, J. Heitmann, W. M. Weber, T. Mikolajick, and H. Riechert
Influence of composition and bottom electrode properties on the local conductivity of TiN/HfTiO2 and TiN/Ru/
HfTiO2 stacks
Appl. Phys. Lett. 98, 012901 (2011)
J16 H. Mähne, S. Slesazeck, S. Jakschik, I. Dirnstorfer, and T. Mikolajick
Influence of the crystallinity on the resistive switching behavior of TiO2
Microelectron. Eng. 88, 1148 (2011)
J17 S. Riedel, J. Neidhardt, S. Jansen, L. Wilde, J. Sundqvist, E. Erben, S. Teichert, and A, Michaelis
Synthesis of SrTiO3 by crystallization of SrO/TiO2 superlattices prepared by atomic layer deposition
J. Appl. Phys. 109, 094101 (2011)
J18 D. Nozaki, J., Kunstmann, F. Zörgibel, W. M. Weber, T. Mikolajick, and G. Cuniberti
Multiscale modeling of nanowire-based Schottky-barrier field-effect transistors for sensor applications
Nanotechnology 35, 325703 (2011)
J19 W. M. Weber, A. Heinzig, and T. Mikolajick
Polarity behavior and adjustment in silicon nanowire Schottky junction transistors
ECS Trans. 35, 93 (2011)
J20 Y. Shua, S. Zhou, S. Streit, H. Reuther, D. Bürger, S. Slesazeck, T. Mikolajick, M. Helm, and H. Schmidt
Reduced leakage current in BiFeO3 thin films with rectifying contacts
Appl. Phys. Lett. 98, 232901 (2011)
J21 M. Grube, D. Martin, W. M. Weber, T. Mikolajick, and H. Riechert
Phase stabilization of sputtered strontium zirconate
Microelectron. Eng. 88, 1326 (2011)
J22 J. Müller, T. S. Böscke, D. Bräuhaus, U. Schröder, U. Böttger, J. Sundqvist, P. Kücher, T. Mikolajick, and L. Frey
Ferroelectric Zr0.5Hf0.5O2 thin films for nonvolatile memory applications
Appl. Phys. Lett. 99, 112901 (2011)
J23 M. Czernohorsky, T. Melde, V. Beyer, M. F. Beug, J. Paul, R. Hoffmann, R. Knöfler, and A. T. Tilke
Influence of metal gate and capping film stress on TANOS cell performance
Mircoelectron. Eng. 88, 1178 (2011)
J24 M. F. Beug, T. Melde, M. Czernohorsky, R. Hoffmann, J. Paul, R. Knöfler, and A. T. Tilke
Analysis of TANOS memory cells with sealing oxide containing blocking dielectrics
IEEE T. Electron. Dev. 58, 1728 (2011)
J25 T. S. Böscke, J. Müller, D. Bräuhaus, U. Schröder, and U. Böttger
Ferroelectricity in hafnium oxide thin films
Appl. Phys. Lett. 99, 102903 (2011)
J26 T. S. Böscke, S. Teichert, D. BräuhausJ. Sundqvist, P. Kücher, T. Mikolajick, and L. Frey
Phase transition in ferroelectric silicon doped hafnium oxide
Appl. Phys. Lett. 99, 112904 (2011)
J27 D. Martin, A. Heinzig, M. Grube, L. Geelhaar, T. Mikolajick, H. Riechert, and W. M. Weber
Direct probing of Schottky barriers in Si nanowire Schottky barrier field effect transistors
Phys. Rev. Lett. 107, 216807 (2011)
J28 J. Müller, U. Schröder, T. S. Böscke, I. Müller, U. Böttger, L. Wilde, J. Sundqvist, M. Lemberger, P. Kücher, T. Mikolajick, and L. Frey
Ferroelectricity in yttrium-doped hafnium oxide
J. Appl. Phys. 110, 114113 (2011)
Publications 2010/2011
Journal Papers - 2010/2011
J29
A. Krause, W. M. Weber, U. Schröder, D. Pohl, B. Rellinghaus, J. Heitmann, and T. Mikolajick
Reduction of leakage currents in nanocrystals embedded in an amorphous matrix in metal-insulator-metal capacitor stacks
Appl. Phys. Lett. 99, 222905 (2011)
J30
A. Heinzig, S. Slesazeck, F. Kreupl, T. Mikolajick, and W. M. Weber
Reconfigurable silicon nanowire transistors
Nano Lett. 12, 119 (2011)
PhD and Diploma Theses, Internship Report
P1
Thomas Melde
Modellierung und Charakterisierung des elektrischen Verhaltens von haftstellen-basierten Flash-Speicherzellen
Technical University Dresden, PhD Thesis (2010)
D1
Maria Tarasova
Analyse von zukünftigen Rückseitenpassivierungen für Solarzellen
Technical University Dresden, Diploma Thesis (2010)
D2
Paul Jordan
Entwicklung einer automatischen Messeinheit für Fotodioden mit durchstimmbarer Empfindlichkeit
University of Applied Sciences Dresden, Diploma Thesis (2011)
D3
André Günther
Messeinheit zur schnellen Erfassung zuverlässigkeitsrelevanter Transistoreigenschaften
University of Applied Sciences Dresden, Diploma Thesis (2011)
D4
Helge Wylezich
Untersuchung von Schaltzuständen resistiver Speicher in Nb2O5
Technical University Dresden, Diploma Thesis (2011)
I1
Paul Jordan
Aufbau eines Messplatzes zur Charakterisierung von optischen Halbleitereigenschaften mittels Photolumineszenzspektroskopie
Technical University Dresden, Internship Report (2011)
Issues of Patent and Patent Applications 2010/2011
Integrated Circuit with Dielectric Layer
US 7.709.359 B (granted May 2010)
Fotodioden und Fotodiodenfeld
DE 10 2010 043 822.7 –33 (Patent Application)
Publications 2010/2011
Talks - 2010/2011
T1
T2
T3
T4
G. Roll, S. Jakschik, M. Goldbach, A. Wachowiak, T. Mikolajick, and L. Frey
Interface defect study by GIDL current and charge pumping measurements on MOSFET devices
DPG - Frühjahrstagung, Dresden, 21.-26.03.2010
A. Krause, D. Martin, M. Grube, and W. M. Weber
CaTiO3 as a high-k dielectric in thin MIM capacitor stacks
DPG - Frühjahrstagung, Dresden, 21.-26.03.2010
M. Grube, D. Martin, W. M. Weber, T. Mikolajick, L. Geelhaar, and H. Riechert
A comparison of SrxZr1-xOy and ZrO2 as potential high-k dielectric for future memory applications
DPG - Frühjahrstagung, Dresden, 21.-26.03.2010
D. Martin, M. Grube, E. Erben, W. Weinreich, U. Schröder, L. Geelhaar, W. M. Weber, H. Riechert, and T. Mikolajick
Nanoscale analysis of the dielectric properties of ultra thin ZrO2-, (ZrO2)(Al2O3)-, ZAZ– films
DPG - Frühjahrstagung, Dresden, 21.-26.03.2010
T5
A. Heinzig, W. M. Weber, T. Rössler, D. Grimm, M. Emmerling, M. Kamp, and T. Mikolajick
First Complementary Field Effect Transistor and Dopant Free Logic
MRS Spring Meeting, San Francisco, 08.04.2010
T6
J. Heitmann and T. Mikolajick
Nanocrystalline materials: Optimization of thin film properties
ECS 2010, Vancouver, 28.04.2010
T7
G. Roll, S. Jakschik, M. Goldbach, A. Wachowiak, T. Mikolajick, and L. Frey
Analysis of the effect of germanium preamorphisation on interface defects and leakage current for high-k MOSFET
WODIM 2010, Bratislava, 29.06.2010
T8
D. Martin, M. Grube, W. Weinreich, J. Müller, L. Wilde, E. Erben, W. M. Weber, U. Schröder, T. Mikolajick, and H.
Riechert
Macroscopic and microscopic electrical characterization of high-k ZrO2 and ZrO2/Al2O3/ZrO2 metal-insulator-metal
structure
WODIM 2010, Bratislava, 30.06.2010
T. Mikolajick
Polarity controllable silicon nanowire Schottky barrier field-effect transistors - a building block for reconfigurable
systems
Nanofair 2010, Dresden, 07.07.2010
T9
T10 G. Roll, S. Jakschik, M. Goldbach, A. Wachowiak, T. Mikolajick, and L. Frey
Carbon junction implant: Effect of leakage currents and defect distribution
ESSDERC 2010, Sevillia, 01.09.2010
T11 U. Schröder, E. Erben, S. Knebel, J. Heitmann, D. Zhou, and T. Mikolajick
Correlation of the electrical characteristics to the structural properties of ALD grown high-k dielectrics
BALD 2010, Hamburg, 16.09.2010
T12 E. Erben, M. Stadtmüller, J. Heitmann, A. Kersch, and T. Mikolajick
Non-conformal growth modes for ZrO2 based dielectrics ALD in high surface area structures
BALD 2010, Hamburg, 16.09.2010
T13 W. M. Weber
Silicon nanowire: Synthesis and electronic devices
Postech, ITCE Pohang (Korea), 22.10.2010 (Invited lecture)
T14 W. M. Weber, A. Heinzig, and T. Mikolajick
Reconfigurable electronics: Enhanced circuit functionality enabled nanotechnology
Postech, World Class University (Pohang, Korea), 23.11.2010
T15 A. Heinzig, W. M. Weber, S. Slesazeck, and T. Mikolajick
Silicon Nanowire Electronics: Growth and Preparation
Neuromimetic Nanocircuits Workshop, Dresden, 14.01.2011
T16 S. Kupke, U. Schröder, S. Knebel, S. Schmelzer, U. Böttger, and T. Mikolajick
PVD grown high-k SrTiO3 for capacitor applications: Reliability leakage current behavior
DPG - Frühjahrstagung, Dresden, 13.-18.03.2011
Publications 2010/2011
Talks - 2010/2011
T17
T18
D. Martin, M. Grube, E. Erben, J. Müller, W. Weinreich, U. Schröder, L. Geelhaar, W. M. Weber, T. Mikolajick, and H.
Riechert
Local I-V characteristics of high-k ultra-thin ZrO2 and ZrO2/Al2O3/ZrO2– films
DPG - Frühjahrstagung, Dresden, 13.-18.03.2011
H. Mähne, S. Slesazeck, S. Jakschik, and T. Mikolajick
The influence of the crystallinity of TiO2 on the resistive switching behavior of memristor devices
DPG - Frühjahrstagung, Dresden, 13.-18.03.2011
T19
A. Krause, W. M. Weber, U. Schröder, J. Heitmann, and T. Mikolajick
Electrical properties of ultrathin CaTiO3 layers in MIM capacitor stacks
DPG - Frühjahrstagung, Dresden, 13.-18.03.2011
T20
S. Döring, S. Jakschik, T. Mikolajick, J. Krause, R. Böhme, and M. Petri
Scanning spreading resistance microscopy for characterization of laser doped selective emitter structures in solar
cells
DPG - Frühjahrstagung, Dresden, 13.-18.03.2011
F. Benner, M. Tarasova, S. Kupke, S. Jakschik, and T. Mikolajick
Comparison of annealing treatments of PVD and ALD Al2O3 passivated silicon for solar cell applications
DPG - Frühjahrstagung, Dresden, 13.-18.03.2011
T21
T22
D. Martin, A. Heinzig, M. Grube, W. M. Weber, L. Geelhaar, H. Riechert, and T. Mikolajick
Direct imaging of nanowire Schottky junctions by scanning gate microscopy
MRS Spring Meeting, San Francisco, 26.04.2011
T23
W. M. Weber, A. Heinzig, D. Martin, S. Slesazeck, and T. Mikolajick
Reconfigurable Nanowire Electronics
M219th ECS Meeting, 01.- 06.05.2011
T24
W. M. Weber, A. Heinzig, D. Martin, S. Slesazeck, and T. Mikolajick
Reconfigurable silicon nanowire circuits, A novel approach for future electronics
7th Chemnitzer Seminar for Nanotechnology and Nanoreliability, Fraunhofer ENAS, 24.05.2011
T25
M. Grube, D. Martin, W. M. Weber, T. Mikolajick, and H. Riechert
Phase stabilization of sputtered strontium zirconate
INFOS, Grenoble, 21.- 24.06.2011
T26
F. Benner, S. Kupke, S. Jakschik, E. Erben, M. Knaut, J. Müller, M. Rose, U. Schröder, and T. Mikolajick
Dielectric backside passivation improvements by Si-doped Al2O3 dielectrics
ALD 2011, Boston, 30.06.2011
T27
W. M. Weber
Silicon to metal silicide nanowire heterostructures: Synthesis and electrical characterization
HZDR Seminar, Dresden, 13.07.2011
T28
J. Beister
Transport in advanced semiconductor devices
HZDR Seminar, Dresden, 02.09.2011
T29
S. Döring, S. Jakschik, T. Mikolajick, P. Eyben, T. Hantschel, and W. Vandervorst
Scanning spreading resistance microscopy as a technique for silicon solar cell emitter structure characterization
26th PVSEC, Hamburg, 05. - 09.2011
T30
W. M. Weber
Thermal treatment on silicon nanowires with Ni-silicide contacts
Subtherm 2011, Dresden, 25.-27.10.2011
Publications 2010/2011
Talks - 2010/2011
T31 A. Krause, W. M. Weber, U. Schröder, and T. Mikolajick
Comparison of electrical properties of thin calcium titanate high-k insulators on RuO2, Pt, and C electrodes
ICMON 2011,, Venice, 28.- 30.11.2011
T32 U. Schröder, J. Müller, K. Yurchuk, S. Slesazeck, D. Martin, S. Müller, D. Bräuhaus, T. Mikolajick, and U. Böttger
Polarization in HfO2 based ALD dielectrics
IMEC ALD Workshop, Leuven, 29.11.2011
T33 T. S. Böscke, J. Müller, D. Bräuhaus, U. Schröder, U. Böttger
Ferroelectricity in Hafnium Oxide: CMOS compatible Ferroelectric Field Effect Transistors
VLSI 2011, Washington, 07.12.2011
Conference contributions - 2010/2011
C1
M. Grube, D. Martin, W. M. Weber, T. Mikolajick, L. Geelhaar and H. Riechert
Improvement of dielectric properties of SrxZr(1-x)Oy grown by molecular beam deposition and sputtering
WODIM 2010, Bratislava, 28.06.2010
C2
A. Krause, W. M. Weber, A. Jahn, D. Pohl, J. Heitmann, U. Schröder, and T. Mikolajick
Deposition, electrical and physical properties of thin calcium titanate high-k insulators
WODIM 2010, Bratislava, 28.06.2010
C3
S. Jakschik, W. M. Weber, A. Ispas, A. Bund, and T. Mikolajick
Silicon and nickel silicide nanowires as anode materials for lithium ion batteries
61th Annual Meeting of the International Society of Electrochemistry, 29.07.2010
C4
E. Erben, H.P. Sperlich, P. Moll, F. Benner, S. Jakschik, J. Bartha, and T. Mikolajick
Effect of ALD process parameters on fixed charges and carrier lifetime - a comparison between ALD, PECVD, and
PVD
BALD 2010, Hamburg, 16.09.2010
W. M. Weber, A. Heinzig, D. Martin, S. Slesazeck, and T. Mikolajick
Reprogrammable nanowire transistors and circuits
ELECMOL’2010, Grenoble, 06.-12.2010
C5
C6
G. Roll, S. Jakschik, M. Goldbach, T. Mikolajick, and L. Frey
Carbon Junction Implant: Effect on Leakage Currents and Defect Distribution
IEEE Conf. Proc. ESSDERC (2010), 329
C7
M. Krupinski, A. Kasic, T. Hecht, M. Klude, J. Heitmann, E. Erben, and T. Mikolajick
Optical characterization of three-dimensional within a DRAM capacitor
SPIE Optical Metrology, Munich, 23.-26.05.2011
Proc. of SPIE vol. 8082, 80823Y (2011)
Hannes Mähne, Stefan Slesazeck, Stefan Jakschik, and Thomas Mikolajick
The influence of crystallinity on the resistive switching behavior of TiO2
INFOS 2011, Grenoble, 21.-24.06.2011
C8
C9
S. Jakschik, E. Erben, F. Benner, S. Kupke, I. Dirnstorfer, M. Rose, I. Endler, T. Mikolajick
Dielectric Backside Passivation – Improvements by Dipole Optimization
Proc. 26th PVSEC p.2252 – 2255 (2011)
C10
M. Knaut, M. Albert, J. W. Bartha, I. Dirnstorfer, T. Hingst, H. Mähne, T. Mikolajick, F. Schlott, K. Dubnack, and G.
Kreisel
Surface conditioning of the TiO2 electrode in dye-sensitized solar cells
26th PVSEC, Hamburg, 05.-09.09.2011
C11
S. Knebel, S. Kupke, G. Roll, S. Jakschik, and T. Mikolajick
Impact of high-k metal gate device reliability on 6T-SRAM cell function
ESSDERC 2011, Helsinki, 12.-16.09.2011
Contacts
Executives (Management)
Scientific director:
Prof. Dr.-Ing. Thomas Mikolajick
Administrative director:
Dr. Alexander Ruf
Research Areas
Competences
Dielectric materials:
Dr. Uwe Schröder
Electrical characterization:
Dr. Stefan Slesazeck
Re-Configurable devices:
Dr. Walter M. Weber
Dr. Stefan Slesazeck
Dr. Uwe Schröder
Optical Characterization:
Dr. Ingo Dirnstorfer
Energy Efficiency Devices
Dr. Andre Wachowiak
Physical Characterization:
Dr. Andre Wachowiak
© NaMLab gGmbH, Dresden 2012