Method for fabricating semiconductor substrate, semiconductor substrate, and semiconductor device

A semiconductor device comprising:

• an SiC substrate having a first region and a second region, the first region provided on a first part of an SiC substrate surface, the second region provided on a second part of the SiC substrate surface, a Z1/2 level density measured by DLTS (Deep Level Transient Spectroscopy) in the first region being 1×1011 cm−3 or less, a Z1/2 level density measured by DLTS in the second region being more than 1×1011 cm−3;
• and
• an n-type SiC layer provided on the SiC substrate, the n-type SiC layer having an impurity concentration of an n-type impurity lower than an impurity concentration of the n-type impurity or a p-type impurity of the SiC substrate,
• wherein the first region and the second region are in direct contact with the SiC layer, and
• wherein the impurity concentration of the n-type or p-type impurity in the SiC substrate is 5×1018 cm−3 or more.