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. 30, 1994
Filed:
May. 27, 1992
Sung T Ahn, Nara, JP;
Shigeki Hayashida, Nara, JP;
Sharp Kabushiki Kaisha, Osaka, JP;
Abstract
A method for preparing a semiconductor device comprises the following steps: (I) depositing at least nitride film on the whole surface of a semiconductor substrate having a field oxide film, (II) removing a portion of the nitride film from a gate-formation region to form an opening at the nitride film up to the substrate, (III) thereafter forming by selective oxidation a vertically projecting oxide film on the substrate at the opening portion, (IV) then removing all the films including the oxide film and the nitride film each covering the substrate to form a dug part of the substrate at the gate formation region, (V) providing on the dug part a gate oxide film and a gate electrode in the order, (VI) doping an impurity ion into the substrate in a manner of self-alignment using the gate electrode as a mask, and (VII) applying heat treatment to the substrate to form an impurity-diffused region.