MOS transistor and differential amplifier circuit with low offset.

摘要

A MOS transistor includes a gate electrode layer (35) formed on an insulation layer (34) which is formed on an element formation region defined by a field insulation layer (31) formed on a P-type semiconductor substrate (30). The gate electrode layer (35) has first and second openings (36a, 36b) formed therein. Further, N-type impurity diffusion regions (37a, 37b) acting as the drain and source of the MOS transistor are formed in those portions of the surface area of the semiconductor substrate (30) which lie under the first and second openings (36a, 36b).