INSULATED GATE FIELD EFFECT TRANSISTOR

摘要

Disclosed is a MOSFET (metal oxide semiconductor field effect transistor) (1) which is capable of reducing the on-resistance by decreasing the channel mobility even when the gate voltage is high. The MOSFET (1) comprises: an n-type substrate (11) that is composed of SiC and has a main surface having an off angle with respect to the {0001} plane of 50-65°; an n-type withstand voltage maintaining layer (13) that is composed of SiC and formed on the main surface (11A) of the substrate (11); a p-type well region (14) that is formed in the withstand voltage maintaining layer (13) at a distance from a first main surface (13A); a gate oxide film (18) that is formed on the well region (14); an n-type contact region (15) that is arranged between the well region (14) and the gate oxide film (18); a channel region (17) that connects the n-type contact region (15) with the withstand voltage maintaining layer (13); and a gate electrode (20) that is arranged on the gate oxide film (18). In the MOSFET (1), a high nitrogen concentration region (23) is formed in a region that contains the interface between the channel region (17) and the gate oxide film (18).