Field effect transistor with decreased substrate control of the channel width

• Main Author: SCHRADER; LOTHAR
• Format: Patent
• Language: English
• Published: 04.08.1981
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; SEMICONDUCTOR DEVICES

An insulated gate field effect transistor has a channel region in a doped semiconductor substrate covered by a thin film region of the insulating layer and has borders defined by thick film regions disposed parallel to the source-drain direction. The transistor further includes a pair of narrow strip zones in the region of the channel borders also running parallel to the source-drain direction which are doped weaker than and oppositely to the substrate doping to partially compensate the substrate doping and in transistors of the depletion type can overcompensate the substrate doping. The compensation provided by the strip zones decreases the substrate control effect so that the effective channel width of the transistor is less susceptible to fluctuations in operating voltages.