SiC-MOSFET and method of manufacturing the same

A metal-oxide-semiconductor field-effect transistor using silicon carbide as a semiconductor material (SiC-MOSFET), comprising:

• a silicon carbide (SiC) substrate;
• and
• a gate electrode located within a trench defined on the SiC substrate,
• wherein the SiC substrate comprises:
• an n-type drain region;
• an n-type drift region located on the n-type drain region, a concentration of n-type impurities in the n-type drift region being lower than a concentration of the n-type impurities in the n-type drain region;
• a p-type body region located on the n-type drift region;
• a p-type contact region located on the p-type body region, the p-type contact region appearing on a surface of the SiC substrate and a concentration of p-type impurities in the p-type contact region being higher than a concentration of the p-type impurities in the p-type body region;
• and
• an n-type source region located on the p-type body region, the n-type source region appearing on the surface of the SiC substrate and a concentration of the n-type impurities in the n-type source region being higher than the concentration of the n-type impurities in the n-type drift region,
• the trench extends from the surface of the SiC substrate to the n-type drift region through the p-type body region,
• the gate electrode faces the n-type source region, the p-type body region and the n-type drift region via a gate insulating film,
• the p-type contact region is a layer formed by epitaxial growth and includes a portion located between the n-type source region and the p-type body region at a location apart from the trench,
• the p-type body region comprises a first body region and a second body region,
• a concentration of the p-type impurities in the second body region is lower than a concentration of the p-type impurities in a portion of the first body region that is in direct contact with the p-type contact region,
• the second body region is in direct contact with both the n-type source region and the p-type contact region, and appears on a side surface of the trench,
• the portion of the p-type contact region located between the n-type source region and the p-type body region is in direct contact with each of the first body region, the second body region and the n-type source region, and
• the second body region is separated from the n-type drift region via the first body region.