Chih-Tang "Tom" Sah (; born in November 1932 in Beijing, China) is a Chinese-American electronics engineer and condensed matter physicist. He is best known for inventing CMOS (complementary MOS) logic with Frank Wanlass at Fairchild Semiconductor in 1963. CMOS is now used in nearly all modern very large-scale integration (VLSI) semiconductor devices.
He was the Pittman Eminent Scholar and a Graduate Research Professor at the University of Florida from 1988 to 2010. 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 (1962-1988) and guided 40 students to the Ph.D. degree in electrical engineering and in physics and 34 MSEE theses. At the University of Florida, he guided 10 doctoral theses in EE. He has published more than 300 peer-reviewed journal articles with his graduate students and research associates, and presented about 200 invited lectures and 60 contributed papers in China, Europe, Japan, Taiwan and in the United States on transistor physics, technology and evolution.
He wrote a three-volume textbook titled Fundamentals of Solid State Electronics (FSSE, 1991). FSSE was translated into Chinese in 2003.
Biography
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 a founding academician of Academia Sinica of China (1928-1949) and served as president of Xiamen University (1937-1945) and Secretary General of Academia Sinica of China (1945-1949). C.-T. Sah also had a younger brother Chih-Han Sah who was a mathematician and professor at the State University of New York at Stony Brook.
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. In 1963, Sah invented the CMOS (complementary MOS) semiconductor device fabrication process with Frank Wanlass at Fairchild. CMOS is now used in nearly all modern LSI and VLSI devices.
He was the founding editor (1991) of the International Series on the Advances in Solid State Electronics and Technology (ASSET) which has published three titles by invited authors (1990s) and eight monographs (2007–2013) by invited authors on compact modelling of devices for computer aided design of integrated circuits, all with the World Scientific Publishing Company, Singapore. His previous (1961-2013) 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. Since 2013, he has been studying condensed matter physics with his young colleague Bin Bin Jie, specifically water physics.