Semiconductor device and manufacturing method thereof

Abstract

As semiconductor regions in contact with a first main surface of a semiconductor base composed by forming an N− silicon carbide epitaxial layer on an N+ silicon carbide substrate connected to a cathode electrode, there are provided both of an N+ polycrystalline silicon layer of a same conduction type as a conduction type of the semiconductor base and a P+ polycrystalline silicon layer of a conduction type different from the conduction type of the semiconductor base. Both of the N+ polycrystalline silicon layer and the P+ polycrystalline silicon layer are hetero-joined to the semiconductor base, and are ohmically connected to the anode electrode. Moreover, the N+ polycrystalline silicon layer of the same conduction type as the conduction type of the semiconductor base is formed so as to contact the first main surface of the semiconductor base, and the P+ polycrystalline silicon layer of the conduction type different from the conduction type of the semiconductor base is formed in trenches dug on the first main surface of the semiconductor base.