SIC semiconductor device and method for manufacturing the same

A SiC semiconductor device comprising:

• a substrate having a first conductive type or a second conductive type and made of SiC;
• a drift layer disposed on the substrate, made of SiC, and having the first conductive type, wherein the drift layer has an impurity concentration lower than the substrate;
• a base region disposed on the drift layer, made of SiC, and having the second conductive type;
• a source region disposed in a surface portion of the base region, made of SiC, and having the first conductive type, wherein the source region has an impurity concentration higher than the drift layer;
• a contact layer electrically coupling between the source region and the base region, and disposed in another surface portion of the base region;
• a trench disposed on a surface of the source region to penetrate the source region and the base region, and having a longitudinal direction;
• a gate insulation film disposed on an inner wall of the trench;
• a gate electrode disposed in the trench via the gate insulation film;
• an interlayer insulation film covering the gate electrode, and having a contact hole, from which the source region and the contact layer are partially exposed;
• a source electrode electrically coupling with the source region and the contact layer via the contact hole;
• a drain electrode disposed on a backside of the substrate opposite to the drift layer;
• and
• a metal silicide film, wherein:
• the source region includes a first source region and a second source region;
• the second source region has an impurity concentration higher than the first source region;
• the second source region is disposed at a position shallower than the first source region and includes a first part and a second part, as well as a first portion and a second portion;
• the first part of the second source region is covered with the interlayer insulation film, and the second part of the second source region is disposed under the contact hole;
• the first part of the second source region includes the first portion at a first position near a surface of the second source region and the second portion at a second position deeper than the first position;
• the first portion of the first part of the second source region has an impurity concentration lower than the second portion of the first part of the second source region;
• the metal silicide film is disposed on the second part of the second source region;
• the metal silicide film is made of metal silicide including metal, which is equal to metal of the source electrode;
• and
• the metal silicide film has a thickness, which is larger than a thickness of the first portion of the first part of the second source region.