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:
Aug. 27, 1996
Filed:
Oct. 11, 1994
Michael Evans, Chippenham, GB;
Abstract
A process for manufacturing a semiconductor switching device (such as a thyristor device) comprises: etching a face of a semiconductor body to provide islands and channels which define a mesa-contoured surface; diffusing dopant of a first conductivity type through said surface so that the lines of equal concentration of the dopant in said body follow substantially the mesa-contoured surface; and diffusing dopant of a second conductivity type into said islands to form p-n junctions with said dopant of a first conductivity type. The diffusion of said dopant of a first conductivity type is followed by an out-diffusion step so that the dopant concentration of said dopant of a first conductivity type is at a maximum at a depth below said surface.