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:
Jul. 29, 2008
Filed:
Mar. 19, 2004
Applicants:
Masaaki Yoshida, Hyogo, JP;
Naohiro Ueda, Hyogo, JP;
Masato Kijima, Hyogo, JP;
Inventors:
Assignee:
Ricoh Company, Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H01L 29/93 (2006.01);
U.S. Cl.
CPC ...
Abstract
A semiconductor device has a configuration in which more than three kinds of wells are formed with small level differences. One kind of well from among the more than three kinds of wells has a surface level higher than other kinds of wells from among the more than three kinds of wells. The one kind of well is formed adjacent to and self-aligned to at least one kind of well from among the other kinds of wells. The other kinds of wells are different in one of a conductivity type, an impurity concentration and a junction depth, and include at least two kinds of wells having the same surface level.