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. 21, 2000
Filed:
Jan. 13, 1998
Applicant:
Inventors:
Assignee:
Ricoh Company, Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H01L / ;
U.S. Cl.
CPC ...
257371 ; 257408 ;
Abstract
A MOS field effect transistor device and fabrication method thereof are provided, which include a non-uniformly doped well region composed of (1) a first portion thereof which is contiguous to a source or drain region, and situated under a gate electrode, and has a first concentration of said first conductive type impurities, and (2) a second.sub.-- portion which has a second concentration higher than the first concentration of said first conductive type impurities. This structure of the field effect transistor has advantages such as, for example, suppressing short channel effects, increasing source or drain junction breakdown voltages and improving high frequency characteristics of the transistor.