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:
Sep. 28, 1976
Filed:
Dec. 24, 1974
William A Edel, Poughkeepsie, NY (US);
Joseph Regh, Wappingers Falls, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A method of making an integrated circuit wherein a subcollector diffusion mask is formed on a semiconductor wafer. A principal impurity of a predetermined conductivity type is then diffused through windows in the mask and into the wafer to form subcollector regions spaced from each other. A compensating impurity of a conductivity type opposite that of the principal impurity is then diffused through the same mask windows into the subcollector regions to a relatively shallow depth. An epitaxial layer is then grown on the wafer during which an amount of the principal impurity diffuses from the subcollector regions into the gas and then into the epitaxial layer and the wafer in areas thereof exterior to the peripheries of the subcollector regions thereby resulting in an autodoping effect. However, the compensating impurity simultaneously diffuses into the exterior areas so as to compensate approximately for the principal impurity and thereby to counteract the autodoping effect of the principal impurity.