The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 02, 1990
Filed:
Apr. 27, 1989
Richard Spitz, Reutlingen, DE;
Vesna Biallas, Reutlingen, DE;
Robert Bosch GmbH, Stuttgart, DE;
Abstract
In making a power diode with high reverse voltage rating, corrosion of the silicon wafer surface by gettering substances is avoided by employing two different diffusion steps. In the first step, boron and phosphorus are respectively applied to opposing major surfaces of the disk-shaped semiconductor body (10) and driven into it by heating to a predetermined temperature. Gettering is employed to increase the charge carrier lifetime and thereby reduce the forward voltage drop of the diode. The gettering is carried out in a second diffusion step at a diffusion temperature sufficiently reduced with respect to the diffusion temperature of the first step to avoid significantly affecting the depth of diffusion of the doping substances into the semiconductor body.