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:
Apr. 13, 1999
Filed:
Mar. 27, 1996
Applicant:
Inventors:
Tatsuhiko Ikeda, Hyogo, JP;
Shunji Kubo, Hyogo, JP;
Masao Yamawaki, Hyogo, JP;
Yasuki Yoshihisa, Hyogo, JP;
Assignee:
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H01L / ;
U.S. Cl.
CPC ...
438723 ; 438733 ; 257517 ;
Abstract
A depression having a depth not exceeding 0.1 .mu.m is formed on the surface of an epitaxial layer. An internal base region is formed just below the depression. An external base region is formed outside the depression. The depression having the above depth can suppress electric field at the end of the internal base in the neighborhood of the junction between the internal base region and the external base region.