A manufacturing method for cascoded junction type field effect transistors.

摘要

A method for manufacturing cascoded junction type field effect transistors comprises the steps of forming an epitaxial layer (33) of a first conductivity type used as a channel region on a semiconductor substrate (32) of a second conductivity type and performing selective oxidation to form a thick oxide film on part of the epitaxial layer (33). Then, the thick oxide film is removed to provide a part of the surface which is a level lower than the main surface of the epitaxial layer (33). Next, an impurity of the first conductivity type is doped into the low and high surface areas of the epitaxial layer (33) from the surface thereof to form source and drain regions (38 and 39) separated at a preset distance. After this, an impurity of the second conductivity type is doped into the low and high level surface areas of the epitaxial layer (33) between the source and drain regions (38 and 39) to simultaneously form first and second junction gates (44 and 45) which are separated at a present distance. Then, the semiconductor substrate (32) is connected to the second junction gate (45) and source region (38) to connect two junction FETs in cascode fashion.