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. 05, 1998
Filed:
May. 10, 1996
Kousuke Yoshida, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
The invention provides an n-channel MOS field effect transistor with an anti-radioactivity. The transistor includes leak guard boron diffusion layers, each of which has a junction surface to an isolation oxide film. The junction surface exists up to a deeper level than a predetermined depth corresponding to a junction surface of n-type source and drain diffusion layers and a p-type silicon substrate. Such leak guard boron diffusion layer is formed by ion-implantation of boron through a gate oxide film, after a formation of the gate oxide film. Such leak guard boron diffusion layers have a higher impurity concentration. The existence of the leak guard boron diffusion layers suppresses a leak to be generated by radiation damages of silicon oxide film such as the gate oxide film and the isolation oxide film.