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:
Jan. 24, 1995
Filed:
Jun. 09, 1987
Jun-ichi Nishizawa, Sendai, JP;
Tadahiro Ohmi, Sendai, JP;
Zaidan Hojin Handotai Kenkyu Shinkokai, Sendai, JP;
Abstract
A semiconductor device having a source region, a drain region and a channel region which are formed in a surface portion of a semiconductor substrate, and a gate formed with a material having a relatively high built-in voltage relative to the source region. This semiconductor device may further include, in the semiconductor substrate to extend along the channel region, a highly-doped region having a conductivity type opposite to that of the source region. This highly-closed region may have an impurity concentration gradient which is greater toward its portion facing the abovesaid surface of the substrate. These arrangements serve to prevent extinction of memory due to current leakage during absence of bias voltage which otherwise would develop in semiconductor devices having short-channel and thin gate oxide layer, and due to irradiation of alpha-particle onto the device.