3D - Flash Memory Summit

3D: Beyond Conventional Flash
and
into the Future
Alper Ilkbahar
VP, 3D Memory Group
SanDisk Corp
Santa Clara, CA USA
August 2008
Alper Ilkbahar, SanDisk 3D
NAND Flash Industry Growth
$350
$20
$18
Billions
NAND Flash ASP and Revenues
$300
$16
$14
$12
$200
$10
$150
$8
Revenues
ASP per GB
$250
$6
$100
$4
$50
$2
$0
$2002
Santa Clara, CA USA
August 2008
2003
Source: Gartner
2004
2005
2006
2007
2008
Alper Ilkbahar, SanDisk 3D
What drives cost-per-bit?
Multiple bit per cell (MLC) technologies
Economies of scale
But beyond everything SCALING
Santa Clara, CA USA
August 2008
Alper Ilkbahar, SanDisk 3D
Flash Revenues vs. ASP
Billions
NAND Flash Revenues vs. log (ASP)
“If we build it (at
the right price),
they will buy it”
$20
$18
$16
$14
Revenues
$12
Exponential ASP
reduction
needed to drive
industry growth
$10
$8
$6
y = -7.91E+09x + 2.31E+10
2
R = 9.58E-01
$4
$2
$0
2.50
2.00
1.50
1.00
log (ASP/1GB)
0.50
We need to
continue scaling
Rev = $23B – 7.9 x log (ASP/GB)
Santa Clara, CA USA
August 2008
Alper Ilkbahar, SanDisk 3D
Can stacking layers of memory
solve our scaling problem?
Relative Cost vs. Number of stacking layers
Relative Cost
1000%
100%
10%
ideal
1%
1
Santa Clara, CA USA
August 2008
2
4
8
16
32
No of Layers
Alper Ilkbahar, SanDisk 3D
Examples of stacked memories:
3D NAND
Samsung, IEDM ’06, ISSCC ‘08
Santa Clara, CA USA
August 2008
Alper Ilkbahar, SanDisk 3D
Additional Layers are not free
• Die size overhead and additional process steps increase cost
Santa Clara, CA USA
August 2008
Alper Ilkbahar, SanDisk 3D
…and yield of each layer is <100%
• Stacking may provide one-time cost benefits, but it alone
is not a replacement for scaling
Santa Clara, CA USA
August 2008
Alper Ilkbahar, SanDisk 3D
3D: Vertical Devices
Another perspective of 3D:
Can we build memory devices in the vertical
dimension that are easier to scale?
Santa Clara, CA USA
August 2008
Alper Ilkbahar, SanDisk 3D
Example of Vertical Devices in a
3D stack: Bit-Cost Scalable Flash
Toshiba, IEDM ‘07
Santa Clara, CA USA
August 2008
Alper Ilkbahar, SanDisk 3D
Ultimate 3D Memory - Scalable and
Stackable Cross-Point Diode Array
Resistance Change Materials
Chalcogenides (PCM)
Metal Oxides
Solid Electrolytes
Magnetic materials
and others…
P
N
Santa Clara, CA USA
August 2008
Alper Ilkbahar, SanDisk 3D
Ultimate 3D Memory - Scalable and
Stackable Cross-Point Diode Array
4 Layers of Memory
Periphery Circuits
Santa Clara, CA USA
August 2008
Alper Ilkbahar, SanDisk 3D
Five Generations of 3D Diode Arrays
8-Layers
250nm
130nm
SCALABLE
&
STACKABLE
4-Layers
80nm
Santa Clara, CA USA
August 2008
45nm
1-Layer
Alper Ilkbahar, SanDisk 3D
Bold
Predictions
NAND Flash will continue scaling beyond current
predictions through not only process and device but
also system-level innovation
Investment in alternative technologies that do not
have a long-term scaling path will have limited
returns
3D diode arrays with the right switching material will
replace Flash
Santa Clara, CA USA
August 2008
Alper Ilkbahar, SanDisk 3D