Silicon carbide semiconductor device, e.g. power MOSFET, comprises gate insulation film disposed on surface of surface channel layer and including high dielectric constant film

摘要

Silicon carbide semiconductor device comprises a gate insulating film on a surface of a surface channel layer and including a high dielectric constant film. Silicon carbide semiconductor device comprises a semiconductor substrate (1) made of single crystal silicon carbide and having a principal surface (1a) and a backside surface (1b) opposite the principal surface; a drift layer made of a first conductive type silicon carbide, on the principal surface of the semiconductor substrate and having a dopant concentration lower than a dopant concentration of the semiconductor substrate; a base region (3a,3b) having a second conductive type, disposed on a predetermined area of the drift layer and having a predetermined thickness; a source region (4a,4b) having the first conductive type, disposed on a predetermined surface portion of the base region and being shallower than a depth of the base region; a surface channel layer (5) made of the first conductive type silicon carbide, on surface portions of both of the drift layer and the base region, and having a predetermined concentration and a predetermined thickness for connecting between the source region and the drift layer; a gate insulating film (7) on a surface of the surface channel layer and including a high dielectric constant film; a gate electrode (8) disposed on the gate insulation film; a source electrode on the source region; and a backside electrode on the backside surface of the semiconductor substrate. Independent claims are also included for: (a) manufacturing a silicon carbide semiconductor device comprising preparing a semiconductor substrate made of single crystal silicon carbide having a principal surface and a backside surface opposite the principal surface; forming a drift layer on the principal surface of the semiconductor substrate; forming a base region on a predetermined area on the drift layer; forming a source region on a predetermined surface portion on the base region; forming a surface channel layer on surface portions of both the drift layer and the base region; forming a gate insulation film including a high dielectric constant film on a surface of the surface channel layer; forming a gate electrode on the gate insulation film; forming a source electrode on the source region; and forming a backside electrode on the backside surface of the semiconductor substrate; (b) a silicon carbide semiconductor substrate comprising a principal surface of the substrate including two surfaces, a (0001)- silicon surface and a surface tilted from a (0001)-Si surface by 10[deg]; and (c) manufacturing a silicon carbide semiconductor substrate comprising preparing a silicon carbide semiconductor substrate having a principal surface tilted from a (0001)-Si surface by 10[deg] by a cutting method; mirror-polishing the principal surface of the silicon carbide semiconductor substrate; and depositing an epitaxial layer (2) epitaxially on the principal surface. .