Chih-Tang Sah

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Chih-Tang Sah
BornNovember 1932 (1932-11) (age 87)
Alma mater Stanford University
University of Illinois at Urbana-Champaign
Scientific career
Institutions University of Florida

Chih-Tang "Tom" Sah (simplified Chinese :萨支唐; traditional Chinese :薩支唐; pinyin :Sà Zhītáng; born in November 1932 in Beijing, China) is a Chinese-American electronics engineer. He is best known for inventing CMOS (complementary MOS) logic with Frank Wanlass at Fairchild Semiconductor in 1963. [1] CMOS is now used in nearly all modern very large-scale integration (VLSI) semiconductor devices. [2]


He is the Pittman Eminent Scholar [3] and a Graduate Research Professor at the University of Florida from 1988. He was a Professor of Physics and Professor of Electrical and Computer Engineering, emeritus, at the University of Illinois at Urbana-Champaign, where he taught for 26 years and guided 40 students to the Ph.D. degree in electrical engineering and in physics and 34 MS EE theses. At the University of Florida, he guided 10 doctoral theses in EE. He has published about 280 journal articles and presented about 170 invited lectures and 60 contributed papers in China, Europe, Japan, Taiwan and in the United States on transistor physics, technology and evolution. [4] [5]

He wrote a three-volume textbook titled Fundamentals of Solid State Electronics (FSSE 1991), FSSE-Study Guide (1993) and FSSE-Solution Manual (1996). The latter included 100 pages of exposition on Transistor Reliability. FSSE was translated into Chinese in 2003.


Sah is a member of the distinguished Fuzhou Sah Family, descendants of the prominent Yuan dynasty official Sadula, in Fuzhou China. His father Pen-Tung Sah was an academician of Academia Sinica and served as president of Xiamen University in the 1920s and 1930s. [6] C.-T. Sah also has a brother Chih-Han Sah who is a mathematician and professor at the State University of New York at Stony Brook. [7]

Sah received two B.S. degrees in 1953 in Electrical Engineering and Engineering Physics from the University of Illinois and the M.S. and Ph.D. degrees from Stanford University in 1954 and 1956, respectively. His doctoral thesis research was on traveling-wave tubes under the tutelage of Karl R. Spangenberg.

His industrial career in solid-state electronics began with William Shockley in 1956 and continued at Fairchild Semiconductor Corporation in Palo Alto from 1959 to 1964 until he became a professor of physics and electrical engineering at the University of Illinois for 25 years (1962–1988). Under the management of Gordon E. Moore, Victor H. Grinich and Robert N. Noyce at Fairchild, Sah directed a 64-member Fairchild Physics Department on the development of the first generation manufacturing technologies (oxidation, diffusion, epitaxy growth, and metal conductor thin film deposition) for volume production of silicon bipolar and MOS transistors and integrated circuit technology including oxide masking for impurity diffusion, stable Si MOS transistor, the CMOS circuit, origin of the low-frequency noise, the MOS transistor model used in the first circuit simulator, thin film integrated resistance and Si epitaxy process for bipolar integrated circuit production.

After the MOSFET (metal-oxide-semiconductor field-effect transistor, or MOS transistor) was first demonstrated by Mohamed Atalla and Dawon Kahng of Bell Labs in early 1960, Sah introduced MOS technology to Fairchild Semiconductor with his MOS-controlled tetrode fabricated in late 1960. [8] In 1963, Sah invented the CMOS (complementary MOS) semiconductor device fabrication process with Frank Wanlass at Fairchild. [1] CMOS is now used in nearly all modern LSI and VLSI devices. [2]

He was the founding editor (1991) of the International Series on the Advances in Solid State Electronics and Technology (ASSET) which published three titles by invited authors (1990s) and is currently publishing six monographs (2007–2008) by invited authors on compact modelling of devices for computer aided design of integrated circuits, all with the World Scientific Publishing Company, Singapore. His current (2007) research has been on MOS transistor models since he was drafted in October 2004 by his young colleagues to join them, after 40 years of absence subsequent to the 1964-Sah, 1965-Sah-Pao and 1966-Pao-Sah journal articles on MOS transistor models, in order to help further in the development of compact models for computer aided design of nanometer MOS integrated circuits.

For contributions in transistor physics and technology, he received the Browder H. Thomson best paper Prize (IRE-1962) for an author under 30, the J. J. Ebers Award in Electron Devices (1981) and the Jack Morton Award (1989), all from the IEEE, the Franklin Institute Certificate of Merit, the First Achievement Award in High Technology from the Asian-American Manufacturer Association in San Jose, CA (1984) (co-recipient with Morris Chang), the Fourth Annual University Research Award of the Semiconductor Industry Association (1998), co recipient in integrated circuit technology (with Yung Cheng Fung) in bioengineering of the first Pioneer recognition Award of the Committee-of-100 (a Chinese-American citizen organization), the second annual Distinguished Lifetime Achievement Award of the Asian-American Engineer of the Year sponsored by the Chinese Institute of Engineering/USA (2003) and the Doctor Honoris Causa degree from the University of Leuven, Belgium (1975) and the Honorary Doctorate from Chiaotung University, Taiwan, R.O.C. (2004).

He was listed in a survey by the Institute for Scientific Information as one of the world's 1000 most cited scientists during 1963-1978. He is a Life Fellow of the American Physical Society, the Franklin Institute and the IEEE, a Fellow of the American Association for the Advancement of Science, a member of the U.S. National Academy of Engineering (1986), the Academia Sinica in Taipei (1998) and the Chinese Academy of Sciences in Beijing (2000). He was appointed an Honorary Professor of Tsinghua University (2003), Peking University (2003) and Xiamen University (2004) of China.

Honors and awards


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  1. 1 2 "1963: Complementary MOS Circuit Configuration is Invented". Computer History Museum . Retrieved 6 July 2019.
  2. 1 2 "1978: Double-well fast CMOS SRAM (Hitachi)" (PDF). Semiconductor History Museum of Japan. Retrieved 5 July 2019.
  3. University of Florida Department of Electrical and Computer Engineering Archived November 12, 2007, at the Wayback Machine
  4. Fundamentals of Solid-State Electronics, Chih-Tang Sah. World Scientific, first published 1991, reprinted 1992, 1993 (pbk), 1994, 1995, 2001, 2002, 2006, ISBN   981-02-0637-2. -- ISBN   981-02-0638-0 (pbk).
  5. Accuracy of Long-Wide Channel Thick-Base MOS Transistor Models, B.B. Jie and Chih-Tang Sah, IEEE Transactions on Electron Devices, vol.54, no.8, August 2007.
  6. (Chinese) Pen-Tung Sah Archived July 7, 2011, at the Wayback Machine , Peking University Health Science Campus
  7. Chih-Han Sah, American Mathematical Society
  8. "1960 - Metal Oxide Semiconductor (MOS) Transistor Demonstrated". The Silicon Engine. Computer History Museum.
  9. "National Chiao Tung University, Honorary Doctorate, 薩支唐". (in Chinese). Retrieved 2018-08-02.