A method of manufacturing a semiconductor device has a step whereby, when forming a gate oxide film, a thin oxide film is left on a silicon substrate onto which it is formed and whereby a heavy metal at the surface of the silicon substrate is diffused into the substrate, and a step of forming a gate...http://www.google.de/patents/US6258635?utm_source=gb-gplus-sharePatent US6258635 - Removal of metal contaminants from the surface of a silicon substrate by diffusion into the bulk
