IRFPA Development in Japan

IRFPA Development in Japan
Masafumi Kimata*
Ritsumeikan University, 1-1-1 Noji-higashi, Kusatsu, Shiga 525-8577, Japan
BIOGRAPHY
Masafumi Kimata: Masafumi Kimata received the B.S. and M.S. degrees in
electronic engineering from Nagoya University in 1974 and 1976, respectively, and
received the Ph.D. degree in engineering science from Osaka University in 1992. He
joined Mitsubishi Electric Corporation in 1976, where he was involved in research
and development of silicon-based infrared focal plane arrays, including Schottkybarrier cooled infrared focal plane arrays and SOI diode uncooled focal plane
arrays. In 2004, he retired from Mitsubishi Electric, and presently he is a professor
at Ritsumeikan University, where he continues his research on MEMS-based
uncooled infrared focal plane arrays and type-II superlattice infrared focal plane
arrays. He was awarded the Prime Minister Prize of the Japan National Invention
Awards in 1993 for his invention of high-resolution Schottky-barrier infrared focal
plane arrays. He is a fellow of SPIE and has been serving as a program committee
member of SPIE's conference on Infrared Technology and Applications since 1992.
TECHNICAL ABSTRACT
Research activities devoted to infrared focal plane arrays (IRFPAs) in Japan have been limited due to the
country’s domestic business environment, and they are very different from those in other countries. This
presentation reviews the history and current state of IRFPA development in Japan.
Development of HgCdTe IRFPAs was active in Japan from the beginning of the 1990s to the mid-2000s.
Not only liquid phase epitaxy (LPE) technology but also molecular beam epitaxy (MBE) and metalorganic
chemical vapor deposition (MOCVD) technologies on alternative substrates, such as GaAs and Si, were
investigated for large-format IRFPAs. A 640×480-element IRFPA for the MWIR band and 256×256-element
IRFPAs for the LWIR band were developed by the mid-2000s1).
In parallel with the development of HgCdTe IRFPAs, considerable efforts were made to develop highresolution PtSi Schottky-barrier IRFPAs. Japan played the leading role in this area and reported a 512×512element IRFPA in 1987 and a 1040×1040 IRFPA in 19912). From the late 1980s, many infrared cameras were
commercialized with the PtSi Schottky-barrier technology. Two space-borne PtSi Schottky-barrier linear
FPAs, with structures of 4096 elements ×4 bands and 2100 elements × 6 bands, were also developed for
Japan Earth Resources Satellite-1 and Earth Observing System-AM1, respectively.
Despite the vigorous efforts of the companies involved in cooled IRFPA development, the domestic
infrared market in Japan did not grow as they expected, and development of cooled IRFPAs became inactive
by the mid-2000s.
However, the Japan Aerospace Exploration Agency (JAXA) has recently acknowledged that Japan needs
its own cooled IRFPA technology to achieve future missions, and thus it initiated a project to develop type-II
superlattice IRFPAs in collaboration with the National Institute of Information and Communications
*[email protected]; phone 81-77-561-5985
Technology (NICT) and Ritsumeikan and Tokushima Universities3). This project is expected to reactivate
R&D in the Japanese sector of the cooled IRFPA industry.
In the arena of uncooled IRFPA technology, Japan is rapidly catching up with the most advanced
American and European companies. The uncooled IRFPAs being developed in Japan are based on the VOx
microbolometer and SOI diode technologies. Both have reached the level where VGA-format IRFPAs with
25-μm-scale pixels are being commercialized. More advanced technologies for 17-μm pixels and beyond
were reported last year4, 5). Mitsubishi Electric has already developed a 15-μm-pixel uncooled IRFPA,
adopting a 2M SOI diode, in collaboration with JAXA6).
In contrast with the United States and Europe, small-format IR array sensors are becoming a noteworthy
trend in Japan. At the CEATEC 2010 exhibition, three companies demonstrated thermopile small-format IR
array sensors with 8×8 to 16×16 pixels and human-detection systems with array sensors. Several other
Japanese companies are also working on the same class of IR array sensors. The application targets for these
small-format IR array sensors seem to be such consumer electronics as air conditioners. Technologies are also
being developed to support the commercialization of uncooled IRFPAs and small-format IR array sensors.
Chip-scale vacuum packaging7) and the development of versatile vacuum packaging equipment8) are
examples of such supporting technology being developed in Japan.
Keywords: Infrared focal plane array, HgCdTe, PtSi Schottky-barrier, uncooled infrared detector,
microbolometer, SOI diode, thermopile
References
1) H. Nishino and N. Oda, “Development History of HgCdTe Infrared Detectors in Japan,” Proc. SPIE, Vol. 7298, pp.
7298 2X-1–15 (2009).
2) M. Kimata, “Schottky-barrier Photoemissive Detectors,” in Infrared Photon Detectors edited by A. Rogalski (SPIE
Press), pp. 299–349 (1995).
3) H. Katayama, J. Murooka, M. Naitoh, T. Imai, R. Sato, E. Tomita, M. Ueno, H. Murakami, S. Kawasaki, K. Bito, M.
Kimata, T. Kitada, T. Isu, M. Patrashin, and I. Hosako, “Development of Type II Superlattice Detector for Future
Space Applications at JAXA,” presented at SPIE conference on Infrared Technology and Applications XXXVIII
(2012).
4) S. Tohyama, T. Sasaki, T. Endoh, M. Sano, K. Katoh, S. Kurashina, M. Miyoshi, T. Yamazaki, M. Ueno, H.
Katayama, and T. Imai, “Uncooled Infrared Detectors toward Smaller Pixel Pitch with Newly Proposed Pixel
Structure,” Proc. SPIE, Vol. 8012, pp. 8012 1M-1–13 (2011).
5) D. Takamuro, T. Maegawa, T. Sugino, Y. Kosasayama, T. Ohnakado, H. Hata, M. Ueno, H. Fukumoto, K. Ishida, H.
Katayama, T. Imai, and M. Ueno, “Development of new SOI diode structure for beyond 17μm pixel pitch SOI diode
uncooled IRFPAs,” Proc. SPIE, Vol. 8012, pp. 8012 1F-1–10 (2011).
6) D. Takamuro, T. Maegawa, Y. Ohta, T. Sugino, Y. Kosasayama, T. Ohnakado, H. Hata, M. Ueno, H. Ohji, R. Sato,
H. Katayama, T. Imai, M. Ueno, “2 million pixel SOI diode uncooled IRFPA with 15μm pixel pitch,” presented at
SPIE conference on Infrared Technology and Applications XXXVIII (2012).
7) M. Takeda, H. Hata, Y. Nakaki, Y. Kosasayama, and M. Kimata, “Chip Scale Vacuum Packaging for Uncooled
IRFPA,” IEEJ Trans. FM, Vol. 127, pp. 405–410 (2007).
8) T. Ito, T. Tokuda, M. Abe, and N. Tokashiki, “Vacuum Packaging Technology for Mass Production of Uncooled
IRFPAs,” Proc. SPIE, Vo. 7298, pp. 7298 2A-1–10 (2009).