Method of preparing a diffused silicon device substrate.

摘要

In a method of preparing a diffused silicon device substrate for use in the fabrication of a MOS power device, a drive-in diffusion step is followed by a thermal donor formation heat treatment which is achieved by heating the silicon device substrate at a temperature from 400 to 500 DEG C for 1 to 20 hours and in a gas atmosphere containing oxygen gas, and subsequently a thermal donor formation retarding heat treatment is performed by heating the silicon device substrate at a temperature of from 600 to 700 DEG C for 8 to 24 hours in a gas atmosphere containing oxygen gas.