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:
Nov. 14, 1995
Filed:
Aug. 29, 1994
Masahiro Shimizu, Hyogo, JP;
Katsuhiro Tsukamoto, Hyogo, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
A method of manufacturing a semiconductor memory device having a peripheral circuit portion, the operating voltage of which is relatively high and a memory array portion, the operating voltage of which is relatively low comprises the steps of forming an inversion preventing layer on the peripheral circuit portion, forming an oxide layer for isolation between-devices adjacent thereto, forming on the memory array portion the inversion preventing layer, the impurity concentration of which is higher than that of the peripheral circuit portion and forming the oxide layer on the peripheral circuit portion at the same time that the oxide layer for isolation between devices is formed adjacent thereto.