Abstract: A method of making a FET includes the steps of forming a source and a drain at respective edges of the surface of a semiconductor substrate, forming a first insulation film on the whole surfaces of the semiconductor substrate, the source, and the drain, coating a photoresist on the first insulation film, patterning the photoresist using a photolithography process to form a photoresist pattern having a first space corresponding to a gate length between the source and the drain, forming a second insulating film on the whole surfaces of the exposed first insulation film and the photoresist pattern, etching the second insulation film to form sidewall insulation films at the sidewalls of the photoresist patterns, etching the first insulation film using the sidewall insulation films and the photoresist pattern as an etching mask to form first insulation film patterns, which form a second space having a width smaller than that of the first space, beneath the first space, removing the sidewall insulation films to for

Abstract: A field effect transistor is disclosed in which a source region and a drain region are formed to be reverse mesa on a semi-insulating semiconductor substrate with an insulating layer thereon by using a crystal growth characteristic corresponding to the crystal orientation. A channel layer and a gate electrode are formed by self-alignment on the upper part of a void formed according to the reverse mesa of the source and the drain regions, so that the channel layer and the semiconductor substrate are electrically separated by the void. By such a construction, a leakage current and backgating effect are removed, and a fast field effect transistor is attained owing to the reduction of an effective channel length and a gate resistance.