Junction field effect transistor having a substantially quadratic characteristic

Claim 1

A junction field effect transistor, which comprises: a semiconductor body having a semiconductor substrate of a first conductivity type; a semiconductor surface region of a second conductivity type opposite to that of the first and located on a first major surface of said substrate; surface-adjoining source and drain zones of said second conductivity type in said surface region and a channel region of said second conductivity type therebetween; a surface-adjoining gate region of said first conductivity type in said surface region and between said source and drain zones which forms a rectifying junction with said channel region; and means for maintaining the value of the quantity β substantially constant over a range of gate-to-source voltage of from zero volts to pinch off, comprising, in combination, a sub-region of the semiconductor substrate of the first conductivity type located at said first major surface and adjacent said channel region, and having a doping concentration which is less than that of the remainder of said substrate and at most approximately equal to that of the adjacent part of the channel region, and means for electrically connecting said surface-adjoining source zone and the underlying semiconductor substrate.