Field effect transistor having a surface channel and its method of

Abstract

A field effect transistor includes a semiconductor substrate of a first conductivity having a source zone and a drain zone of an opposite, second conductivity spaced apart therein and extending to the surface thereof. A surface channel adjoins the surface, is of the second conductivity, and extends in an area located between the source and drain zones. A gate electrode is carried above the surface channel, either on an insulator, or directly on the surface to form a Schottky junction. A second zone lies beneath the surface below or in overlapping relation to the surface channel and extends between the drain and source zones. The second channel is doped with dopant particles whose energy level in the forbidden band of the semiconductor substrate, at an operating temperature T, lies at a distance of more than 1/2 kT from the conduction band edge and valence band edge of the semiconductor substrate. Application of proper potentials with respect to the start voltage required for ionization of the dopant particles in the second channel causes the field effect transistor to function as a high-speed switch. Connection of the field effect transistor in series with a resistance between the poles of a power supply which has a voltage greater than the start voltage causes the field effect transistor to operate, in combination with the resistor, as an oscillator.