Computer History MuseumSemiconductor History

1963 - Complementary MOS Circuit Configuration is Invented

Frank Wanlass invents the lowest power logic configuration but performance limitations impede early acceptance of today's dominant manufacturing technology.

In a 1963 conference paper C. T. Sah and Frank Wanlass of the Fairchild R & D Laboratory showed that logic circuits combining p-channel and n-channel MOS transistors in a complementary symmetry circuit configuration drew close to zero power in standby mode. Wanlass patented the idea that today is called CMOS.

RCA Research Laboratories and the Somerville manufacturing operation pioneered the production of CMOS technology (under the trade name COS/MOS) for very low-power integrated circuits, first in aerospace and later in commercial applications. Gerald Herzog led a major CMOS logic and memory circuit design program for an Air Force computer in 1965. In 1968 the company demonstrated a 288-bit static RAM and introduced the first members of the popular CD4000 family of general-purpose logic devices. Using a unique silicon-gate, closed-geometry CMOS process to minimize leakage, RCA's 1975 COSMAC 1802 microprocessor was the forerunner of millions of engine control processors built for Chrysler automobiles.

The first high-volume applications for CMOS circuits emerged in battery-operated consumer products such as digital watches (1974 Milestone) and portable instruments that did not demand the ultimate in speed. By 1978, when Toshiaki Masuhara of Hitachi described a high-speed RAM at ISSCC, the combination of smaller lithography with the silicon-gate process enabled CMOS to compete in performance with bipolar and conventional MOS. As designers took advantage of scaling (1974 Milestone) to pack hundreds of thousands of transistors onto a chip, CMOS provided the best solution to manage the resulting power density issues.



Contemporary Documents

Wanlass, F. M. and Sah, C.T. "Nanowatt Logic Using Field-Effect Metal-Oxide Semiconductor Triodes," International Solid State Circuits Conference Digest of Technical Papers (February 20, 1963) pp. 32-33.

Wanlass, F. M "Low Stand-By Power Complementary Field Effect Circuitry." U. S. Patent 3,356,858 (Filed June 18, 1963. Issued December 5, 1967).

Ahrons, R., Mitchell, M., Burns, J. "MOS micropower complementary transistor logic," IEEE International Solid-State Circuits Conference. Digest of Technical Papers. 1965 Vol. VIII (February 1965) pp. 80-81.

Hanchett, C., Katz, S., Yung, A. K. "Complementary MOS Memory Arrays," Government Microcircuits Applications Conference, Reprinted as RCA Publication No. ST-3814 (October 1968)

Masuhara, T. Minato, O. Sasaki, T. Sakai, Y. Kubo, M. Yasui, T. "A high-speed, low-power Hi-CMOS 4K static RAM," IEEE International Solid-State Circuits Conference. Digest of Technical Papers 1978 Vol. XXI (February 1978) pp. 110-111.

More Information

Sah, C.T. "Evolution of the MOS Transistor" Proceedings of the IEEE, Vol. 76, Issue 10 (1988) p. 1295.

Weimer, Paul K. "An Earlier CMOS Patent," IEEE Spectrum (February 1992).

Bassett, Ross Knox. To the Digital Age. (Baltimore: The Johns Hopkins University Press, 2002) p. 51, 162-163.