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:
Mar. 21, 2006
Filed:
Jan. 14, 2004
Hiroaki Nakaoka, Kyoto, JP;
Akio Sebe, Kanagawa, JP;
Takayuki Yamada, Osaka, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
Impurities for threshold voltage adjustment are implanted using a resist film and a protective dielectric as implantation masks from directions inclined at 10° through 30° with respect to the direction vertical to the principal surface of a semiconductor substratewhen viewed in cross section taken along the gate width direction. Thus, first low-concentration impurity implantation regions are formed to overlap each other in the central part of an active region for a memory cell MIS transistor Mtrs of an SRAM. Furthermore, after an isolation is formed, a second low-concentration impurity implantation region is formed in an active region for each of MIS transistors Ltr, Mtrs and Mtrl by implanting impurity ions without using implantation masks. The MIS transistors Ltr, Mtrs and Mtrl formed after the completion of the fabricating process have substantially the same threshold voltage.