Method of manufacturing a semiconductor device that includes a process for forming a high breakdown voltage field effect transistor

Abstract

With the objective of suppressing or preventing a kink effect in the operation of a semiconductor device having a high breakdown voltage field effect transistor, ntype semiconductor regions, each having a conduction type opposite to ptype semiconductor regions for a source and drain of a high breakdown voltage pMIS, are disposed in a boundary region between each of trench type isolation portions at both ends, in a gate width direction, of a channel region of the high breakdown voltage pMIS and a semiconductor substrate at positions spaced away from ptype semiconductor regions, each having a field relaxing function, of the high breakdown voltage pMIS, so as not to contact the ptype semiconductor regions (on the drain side, in particular). The ntype semiconductor regions extend to positions deeper than the trench type isolation portions.