JPS6476775A - Manufacture of junction type field-effect transistor - Google Patents

Abstract

PURPOSE:To thinly form a second semiconductor layer and a gate impurity region, and improve the cotrollability of channel thickness, by forming a first semiconductor layer and a second semiconductor layer of inverse conductivity type wherein a part is eliminated, on a conductivity type semiconductor substrate, and selectively introducing a conductivity type impurity into the eliminated part to form a gate impurity region. CONSTITUTION:A first N-type epitaxial layer 2 is subjected to etching, by using a thermal oxide film 3 to a mask, and a P-type semiconductor substrate 1 is exposed. On the whole surface, a second N-type epitaxial layer 5 is formed in thickness of 1-2mum. By using a mask such as oxide film and photo resist, P-type impurity in the recessed part of the second N-type epitaxial layer 5 is selectively introduced to form a P-type impurity region 6 in thickness of 0.5-1mum. In the second epitaxial layer 5 between the region 6 and the substrate 1, a channel is formed by the impurity region 6. The thickness tepi to determine the channel thickness (d), and the thickness tp of the region 6 can be made less than or equal to one-half of prior ones. Therefore, the channel thickness (d) can be very precisely formed, and the controllability of drain.source current is improved.