Patent ID: 9496366
Filing Date: 2016-11-15
CPC Classification: H01L

Claim Text:
1. A method for manufacturing a silicon carbide semiconductor device comprising the steps in the following order: a first step of forming a thermal oxide film on one surface of an SiC substrate by thermal oxidation at a temperature of 1150° C. or above in a gas atmosphere including molecules which contain nitrogen and oxygen, and introducing nitrogen to said one surface of the SiC substrate in the course of forming the thermal oxide film; a second step of forming an n++ type SiC layer on said one surface of the SiC substrate such that the thermal oxide film is removed from said one surface of the SiC substrate by etching and, thereafter, said one surface of the SiC substrate is exposed to radicals so that Si—N bonded bodies and C—N bonded bodies which are formed on said one surface of the SiC substrate in the course of introducing nitrogen into said one surface of the SiC substrate are removed while leaving nitrogen introduced into a lattice of SiC out of the nitrogen introduced into said one surface of the SiC substrate; and a third step of forming an ohmic electrode layer on said one surface of the SiC substrate wherein the first step is carried out under a condition where nitrogen concentration on a boundary surface between the thermal oxide film and the SiC substrate is 5×10