Silicon carbide semiconductor device and fabrication method of silicon carbide semiconductor device

A silicon carbide semiconductor device comprising:

• a first-conductivity-type wide band gap semiconductor substrate;
• a first-conductivity-type wide band gap semiconductor deposition layer deposited on a surface of the first-conductivity-type wide band gap semiconductor substrate and having an impurity concentration that is lower than that of the first-conductivity-type wide band gap semiconductor substrate;
• a first second-conductivity-type semiconductor region selectively disposed in a surface layer of the first-conductivity-type wide band gap semiconductor deposition layer on a side opposite to the first-conductivity-type wide band gap semiconductor substrate;
• an element structure made up of a metal film forming a Schottky junction with the first-conductivity-type wide band gap semiconductor deposition layer and the first second-conductivity-type semiconductor region;
• a second second-conductivity-type semiconductor region selectively disposed in a surface layer of the first-conductivity-type wide band gap semiconductor deposition layer on the side opposite to the first-conductivity-type wide band gap semiconductor substrate, the second second-conductivity-type semiconductor region surrounding a peripheral portion of the element structure;
• and
• a third second-conductivity-type semiconductor region surrounding a peripheral portion of the second second-conductivity-type semiconductor region to make up a junction terminal structure, wherein
• any one among the first and second second-conductivity-type semiconductor regions has an acceptor concentration that is greater than or equal to a predetermined concentration.

A fabrication method of a silicon carbide semiconductor device comprising, the fabrication method comprising:

• depositing on a surface of a first-conductivity-type wide band gap semiconductor substrate, a first-conductivity-type wide band gap semiconductor deposition layer having an impurity concentration that is lower than that of the first-conductivity-type wide band gap semiconductor substrate;
• selectively forming a first second-conductivity-type semiconductor region in a surface layer of the first-conductivity-type wide band gap semiconductor deposition layer on a side opposite to the first-conductivity-type wide band gap semiconductor substrate;
• forming an element structure from a metal film forming a Schottky junction with the first-conductivity-type wide band gap semiconductor deposition layer and the first second-conductivity-type semiconductor region;
• selectively forming a second second-conductivity-type semiconductor region in a surface layer of the first-conductivity-type wide band gap semiconductor deposition layer to surround a peripheral portion of the first second-conductivity-type semiconductor region;
• and
• selectively forming in a surface layer of the first-conductivity-type wide band gap semiconductor deposition layer, a third second-conductivity-type semiconductor region having an impurity concentration that is lower than that of the second second-conductivity-type semiconductor region, the third second-conductivity-type semiconductor region surrounding a peripheral portion of the second second-conductivity-type semiconductor region to make up a junction termination structure, wherein
• any one among the first and second second-conductivity-type semiconductor regions has an acceptor concentration greater than or equal to a predetermined concentration.