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Featured researches published by Shigeo Ohshima.


international solid state circuits conference | 2007

A 56-nm CMOS 99-

Ken Takeuchi; Yasushi Kameda; Susumu Fujimura; Hiroyuki Otake; Koji Hosono; Hitoshi Shiga; Yoshihisa Watanabe; Takuya Futatsuyama; Yoshihiko Shindo; Masatsugu Kojima; Makoto Iwai; Masanobu Shirakawa; Masayuki Ichige; Kazuo Hatakeyama; Shinichi Tanaka; Teruhiko Kamei; Jia-Yi Fu; Adi Cernea; Yan Li; Masaaki Higashitani; Gertjan Hemink; Shinji Sato; Ken Oowada; Shih-Chung Lee; Naoki Hayashida; Jun Wan; Jeffrey W. Lutze; Shouchang Tsao; Mehrdad Mofidi; Kiyofumi Sakurai

A single 3.3-V only, 8-Gb NAND flash memory with the smallest chip to date, 98.8 mm2, has been successfully developed. This is the worlds first integrated semiconductor chip fabricated with 56-nm CMOS technologies. The effective cell size including the select transistors is 0.0075 mum2 per bit, which is the smallest ever reported. To decrease the chip size, a very efficient floor plan with one-sided row decoder, one-sided page buffer, and one-sided pad is introduced. As a result, an excellent 70% cell area efficiency is realized. The program throughput is drastically improved to twice as large as previously reported and comparable to binary memories. The best ever 10-MB/s programming is realized by increasing the page size from 4kB to 8kB. In addition, noise cancellation circuits and the dual VDD-line scheme realize both a small die size and a fast programming. An external page copy achieves a fast 93-ms block copy, efficiently using a 1-MB block size


IEEE Journal of Solid-state Circuits | 1993

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Natsuki Kushiyama; Shigeo Ohshima; D. Stark; H. Noji; Kiyofumi Sakurai; Satoru Takase; Tohru Furuyama; R.M. Barth; A. Chan; J. Dillon; James A. Gasbarro; M.M. Griffin; Mark Horowitz; T.H. Lee; Victor E. Lee

A 512-kb*9 DRAM with a 500-Mbyte/s data transfer rate was developed. This high data rate was achieved by designing a DRAM core with a very high internal column bandwidth, and coupling this core with a block-oriented, small-swing, synchronous interface that uses skew-canceling clocks. The DRAM has a 1-kbyte*2-line sense-amp cache and is assembled in a 32-pin vertical surface-mount-type plastic package. The measurement results clearly verified the 500-Mbyte/s data rate. >


international solid-state circuits conference | 2006

8-Gb Multi-Level NAND Flash Memory With 10-MB/s Program Throughput

Ken Takeuchi; Yasushi Kameda; Susumu Fujimura; Hiroyuki Otake; Koji Hosono; Hitoshi Shiga; Y. Watanabe; Takuya Futatsuyama; Yoshihiko Shindo; Masatsugu Kojima; Makoto Iwai; Masanobu Shirakawa; Masayuki Ichige; Kazuo Hatakeyama; Sumio Tanaka; Teruhiko Kamei; Jia-Yi Fu; Adi Cernea; Yan Li; Masaaki Higashitani; Gertjan Hemink; Shinji Sato; Ken Oowada; Shih-Chung Lee; N. Hayashida; Jun Wan; Jeffrey W. Lutze; Shouchang Tsao; Mehrdad Mofidi; Kiyofumi Sakurai

Fabricated in 56nm CMOS technology, an 8Gb multi-level NAND Flash memory occupies 98.8mm2, with a memory cell size of 0.0075mum/b. The 10MB/s programming and 93ms block copy are also realized by introducing 8kB page, noise-cancellation circuits, external page copy and the dual VDD scheme enabling efficient use of 1MB blocks


symposium on vlsi circuits | 1992

A 500-megabyte/s data-rate 4.5 M DRAM

Natsuki Kushiyama; Shigeo Ohshima; D. Stark; Kiyofumi Sakurai; Satoru Takase; T. Furuyuma; B. Barth; J. Dillon; James A. Gasbarro; M. Griffin; Mark Horowitz; V. Lee; W. Lee; W. Leung

A novel 512-kb*9 DRAM with a 500-Mbyte/s data transfer rate has been designed. This high data-rate has been achieved by coupling a very high internal column bandwidth DRAM core with a very high internal column bandwidth, and coupling this core with a block oriented, small-swing, synchronous interface that uses skew canceling clocks. The DRAM has a 1-kbyte*2 line sense amplifier cache. This DRAM is assembled in a 32-pin vertical surface mount type plastic package.<<ETX>>


international solid-state circuits conference | 2008

A 56nm CMOS 99mm2 8Gb Multi-level NAND Flash Memory with 10MB/s Program Throughput

Kazushige Kanda; Masaru Koyanagi; Toshio Yamamura; Koji Hosono; Masahiro Yoshihara; Toru Miwa; Yosuke Kato; Alex Mak; Siu Lung Chan; Frank Tsai; Raul Adrian Cernea; Binh Le; Eiichi Makino; Takashi Taira; Hiroyuki Otake; Norifumi Kajimura; Susumu Fujimura; Yoshiaki Takeuchi; Mikihiko Itoh; Masanobu Shirakawa; Dai Nakamura; Yuya Suzuki; Yuki Okukawa; Masatsugu Kojima; Kazuhide Yoneya; Takamichi Arizono; Toshiki Hisada; Shinji Miyamoto; Mitsuhiro Noguchi; Toshitake Yaegashi

NAND flash memory use in digital still cameras and cellular phones is driving demand for larger-capacity storage. Moreover, NAND flash has the potential to replace HDDs. To achieve larger capacity while maintaining low cost per bit, technical improvements in feature size and area reduction are essential. To meet the stringent requirements, we develop a 16 Gb 4-level NAND flash memory in 43 nm CMOS technology. In 43 nm generation, gate-induced drain leakage (GIDL) influences the electrical field on both sides of NAND strings. GIDL causes severe program disturb problems to NAND flash memories. To avoid GIDL, two dummy wordlines (WL) on both sides of NAND strings are added. This is effective because the dummy gate voltages, are selected independent of the program inhibit voltage.


international solid-state circuits conference | 2009

500 Mbyte/sec data-rate 512 Kbits*9 DRAM using a novel I/O interface

Takuya Futatsuyama; Norihiro Fujita; Naoya Tokiwa; Yoshihiko Shindo; Toshiaki Edahiro; Teruhiko Kamei; Hiroaki Nasu; Makoto Iwai; Koji Kato; Yasuyuki Fukuda; Naoaki Kanagawa; Naofumi Abiko; Masahide Matsumoto; Toshihiko Himeno; Toshifumi Hashimoto; Yi-Ching Liu; Hardwell Chibvongodze; Takamitsu Hori; Manabu Sakai; Hong Ding; Yoshiharu Takeuchi; Hitoshi Shiga; Norifumi Kajimura; Yasuyuki Kajitani; Kiyofumi Sakurai; Kosuke Yanagidaira; Toshihiro Suzuki; Yuko Namiki; Tomofumi Fujimura; Man Mui

NAND flash memories are used in digital still cameras, cellular phones, MP3 players and various memory cards. As seen in the growing needs for applications such as solid-state drives and video camcoders, the market demands for larger-capacity storage has continuously increased and NAND Flash memories are enabling a wide range of new applications. In such situations, to achieve larger capacity at low cost per bit, technical improvement in feature-size scaling [1], multi-bit per cell [2,3] and area reduction are essential.


international electron devices meeting | 2007

A 120mm 2 16Gb 4-MLC NAND Flash Memory with 43nm CMOS Technology

Mitsuhiro Noguchi; Toshitake Yaegashi; H. Koyama; Mutsuo Morikado; Yutaka Ishibashi; S. Ishibashi; K. Ino; K. Sawamura; T. Aoi; T. Maruyama; Akihiro Kajita; E. Ito; M. Kishida; K. Kanda; Koji Hosono; S. Miyamoto; F. Ito; G. Hemink; Masaaki Higashitani; A. Mak; J. Chan; M. Koyanagi; Shigeo Ohshima; Hideki Shibata; H. Tsunoda; Sumio Tanaka

Multi-level programming is demonstrated with 43 nm-node NAND floating-gate megabit cells for the first time, by thinning an inter-gate dielectric film to less than 13 nm. 43 nm-node cobalt-silicide control-gate and copper bit-line technologies are developed to achieve low resistances of the word lines and bit lines.


Archive | 2002

A 113mm2 32Gb 3b/cell NAND flash memory

Kazuaki Kawaguchi; Shigeo Ohshima


Archive | 1998

A High-performance Multi-level NAND Flash Memory with 43nm-node Floating-gate Technology

Hiroyuki Ohtake; Shigeo Ohshima; Takehiro Hasegawa


Archive | 1998

Synchronous semiconductor memory

Shigeo Ohshima

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