Method for producing semiconductor device

Abstract

A method for producing a semiconductor device is disclosed which includes a diffusion step of forming, on a CZ-FZ silicon semiconductor substrate, a deep diffusion layer involving a high-temperature and long-term thermal diffusion process which is performed at a thermal diffusion temperature of 1290° C. to a melting temperature of a silicon crystal for 100 hours or more; and a giving step of giving a diffusion source for an interstitial silicon atom to surface layers of two main surfaces of the silicon semiconductor substrate before the high-temperature, long-term thermal diffusion process. The step of giving the diffusion source for the interstitial silicon atom to the surface layers of the two main surfaces of the silicon semiconductor substrate is performed by forming thermally-oxidized films on two main surfaces of the silicon semiconductor substrate or by implanting silicon ions into surface layers of the two main surfaces of the silicon semiconductor substrate.