Method of preparing diffused silicon device substrate
AssigneeShin-Etsu Handotai Co., Ltd.
InventorsYasushi Yoshimura, Takeshi Akatsuka, Junichi Okada
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Abstract
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.degree. to 500.degree. 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.degree. to 700.degree. C. for 8 to 24 hours in a gas atmosphere containing oxygen gas.
Claims2
A method of preparing a diffused silicon device substrate for use in the fabrication of a MOS power device, comprising the steps of:
- (a) effecting drive-in diffusion to thereby diffuse an impurity over a silicon device substrate;
- (b) subsequently performing a thermal donor formation heat treatment by heating the silicon device substrate at a temperature from 400.degree. to 500.degree. C. for 1 to 20 hours and in a gas atmosphere containing oxygen gas;
- and
- (c) thereafter effecting a thermal donor formation retarding heat treatment by heating the silicon device substrate at a temperature from 600.degree. to 700.degree. C. for 8 to 24 hours in a gas atmosphere containing oxygen gas.
Dependencies are inferred from the claim text.