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. 04, 1999
Filed:
Sep. 23, 1997
Takahiro Ohnakado, Hyogo, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
A nonvolatile semiconductor memory device is obtained of which tunnel oxide film can be made thinner and which can allow low voltage and power consumption. P type polycrystal silicon is used as a floating gate electrode. Thickness of a tunnel oxide film (first insulating film) is set to less than 10 nm. By using P type polysilicon as a material of the floating gate electrode, a barrier height of a well-type potential is increased from 3.1 eV to 4.4 eV, and thus the leak current is effectively prevented. Thus, the film thickness of the tunnel oxide film can be made less than 10 nm, and operating voltage can also be lowered. Therefore, reduction in power consumption and improvement in performance of the nonvolatile semiconductor memory device can be achieved.