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:
Jun. 10, 2003
Filed:
May. 24, 2001
Applicant:
Inventors:
Hiroyuki Takazawa, Hino, JP;
Tohru Oka, Kokubunji, JP;
Isao Ohbu, Sagamihara, JP;
Yoshinori Imamura, Sagamiko, JP;
Assignee:
Hitachi, Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01L 3/10328 ;
U.S. Cl.
CPC ...
H01L 3/10328 ;
Abstract
A semiconductor device including a bipolar transistor having an emitter layer consisting of a semiconductor containing indium, and a protective insulating film containing silicon and oxygen which is formed on the surface of the guard ring of the emitter layer, wherein the protective insulating film has a density of oxygen of less than 7×10 cm . This semiconductor device prevents performance deterioration and ensures high performance in a power amplifier.