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:
May. 29, 1990
Filed:
Apr. 07, 1988
Osamu Matsumoto, Yokohama, JP;
Tadashi Maruyama, Yokohama, JP;
Hiroyoshi Murata, Yokohama, JP;
Isao Abe, Kawasaki, JP;
Tomohisa Shigematsu, Yokohama, JP;
Kazuyoshi Shinada, Yokohama, JP;
Yasoji Suzuki, Yokohama, JP;
Ichiro Kobayashi, Yokohama, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
A memory cell of a nonvolatile semiconductor memory device includes a P conductive type semiconductor substrate, first and second diffusion layers of an N conductivity type, formed in the substrate, a channel region formed in the surface region of the substrate, and which is located between the first and second diffusion layers, a floating gate electrode formed on the channel region, and a control gate electrode formed on the floating gate electrode. The memory cell further includes a third diffusion layer of the N conductivity type, and formed between the first layer and the channel region, the third layer having an impurity concentration lower than that of the first layer.