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. 22, 1981
Filed:
Oct. 16, 1979
Hitachi, Ltd., Tokyo, JP;
Abstract
A method of diffusing selectively aluminium into a single crystal silicon semiconductor substrate for fabricating a semiconductor device comprises the steps of forming a diffusion source layer of aluminium having a predetermined thickness on at least one of the major surfaces of the substrate in a predetermined pattern, forming an oxide film of a predetermined thickness through oxidation over the surface of the diffusion source layer and the exposed surface of the substrate, and heating the substrate inclusive of the exposed surface thereof and the diffusion source layer thereby to diffuse aluminium into the substrate. The thickness of the oxide film is so selected as to suppress vaporization of the aluminium and at the same time to be used as a diffusion mask without giving rise to crystallization into a cristobalite structure. The method allows the pattern of boundary between the diffused regions and non-diffused regions as well as concentration profile of the diffused region to be controlled in a desired manner with a high accuracy.