United States Patent 3,476,991
November 4, 1969

Inversion Layer Field Effect Device With Azimuthally Dependent Carrier Mobility
Jack P. Mize
Derek Colman

Filed November 8, 1967
Image of US PATENT 3,476,991

Abstract of the Disclosure

An integrated circuit in which metal-oxide-semiconductor field effect transistors are formed on a surface disposed parallel to the (110) crystallographic plane of a silicon crystal. The carrier mobility in a thin inversion layer parallel to the (110) plane is azimuthally dependent, and is a maximum in either direction perpendicular to the (1'10) plane and is a minimum in the direction perpendicular to the (001) plane. The integrated circuit includes a driver transistor which is oriented such that current flows normal to the (1'10) plane for maximum carrier mobility, and a load transistor which is oriented such that current flows normal to the (001) plane for minimum carrier mobility. The resulting circuit occupies a minimum area of the surface of the crystal.
Figure descriptions: cover graphic

  • Figure 1 is a plan view of a Hall bar device used to collect mobility data.
  • Figure 2 is a graph illustrating the carrier mobility with respect to gate voltage in p-type inversion layers formed parallel to various crystallographic planes in silicon and in various aximuthal directions within the plane.
  • Figure 3 is a schematic circuit diagram of a typical inverter formed by MOS field effect transistors.
  • Figure 4 is a simplified plan view illustrating how the inverter of Figure 3 can be geometrically arranged in an integrated circuit in accordance with a specific aspect of the present invention.

 Citations [54]:
2,994,811 08/1961 Senitzky 3,370,995 09/1965 Lowery 3,302,078 01/1967 Skellett 3,378,783 04/1968 Gibson 3,407,343 10/1968 Fang 3,410,132 11/1968 Hall
National Museum of American History
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