Patent ID: 7816688

Claim:
A semiconductor device, characterized by comprising: a SiC substrate including a source region and a drain region; a gate insulating film formed on part of the SiC substrate, said gate insulating film includes a first insulating film formed by oxidizing part of the SiC substrate and a second insulating film deposited over the first insulating film; a first cap layer between the first insulating film and the second insulating film; and a gate electrode formed on the gate insulating film, wherein a transition layer with a thickness of 1 nm or less is formed in an interface region between the SiC substrate and the gate insulating film, the first cap layer has a thickness of 0.5 nm to 10 nm, both inclusive, the first cap layer is made of an oxynitride film having an N/(N+O) value of 0.1 to 0.5, both inclusive, the second insulating film has a thickness of 50 nm to 200 nm, both inclusive, and the first insulating film has a thickness of 0.5 nm to 20 nm, both inclusive.