PURPOSE: To decrease resistance in a channel region to improve characteristics in noise and besides gate-reverse withstand voltage, by widening both source and drain regions having high carrier concentration gradually in the depth direction to the gate side from the operation layer surface so that the source and drain electrodes are formed over the vicinity of the boundaries of their respective regions with a channel region.

CONSTITUTION: A source electrode 7 and drain electrode 8 are formed over the vicinity of the boundary of their respective regions 4 and 5 on the surface of an operation layer 3. Because the source region 4 comes close to the drain region 5, effective length at a channel region is shortened to decrease the source resistance. Both of the source electrode 7 and drain electrode 8 are necessarily formed apart from the gate electrode 6, and the source region 4 and drain region 5 are composed to be almost covered with respectively the source electrode 7 and drain electrode 8, and therefore, the configuration is formed where the region 7 and drain region 8 are not disposed very close to the gate electrode 6, thereby the characteristics of gate-reverse withstand voltage can be improved.