SILICON CARBIDE SEMICONDUCTOR DEVICE AND METHOD OF MANUFACTURING SILICON CARBIDE SEMICONDUCTOR DEVICE

摘要

In forming an ohmic electrode on a back surface of an n-type SiC substrate, an n+-type semiconductor region is formed in a surface layer of the back surface of an n-type epitaxial substrate by ion implantation. In this ion implantation, the impurity concentration of the n+-type semiconductor region is a predetermined range and preferably a predetermined value or less, and an n-type impurity is implanted by acceleration energy of a predetermined range such that the n+-type semiconductor region has a predetermined thickness or less. Thereafter, a nickel layer and a titanium layer are sequentially formed on the surface of the n+-type semiconductor region, the nickel layer is heat treated to form a silicide, and the ohmic electrode formed from nickel silicide is formed. In this manner, a back surface electrode that has favorable properties can be formed while peeling of the back surface electrode can be suppressed.

主权项

1. A method of manufacturing a silicon carbide semiconductor device, comprising:
implanting an impurity into a back surface of a semiconductor substrate formed from silicon carbide to thereby form in a surface layer of the back surface of the semiconductor substrate a high-concentration semiconductor region that has an impurity concentration that is higher than that of the semiconductor substrate; forming a metal electrode on a surface of the high-concentration semiconductor region; and performing a heat treatment to form an ohmic contact of the metal electrode and the high-concentration semiconductor region, wherein the impurity concentration of the high-concentration semiconductor region is a range from 1×1019/cm3 to 8×1020/cm3, a thickness of the high-concentration semiconductor region is a first thickness of 200 nm or less, and the impurity is implanted by acceleration energy of 150 keV or less.