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. 29, 2004
Filed:
Apr. 07, 2003
Applicant:
Inventors:
Akira Yoshioka, Kanagawa, JP;
Tetsuro Nozu, Tokyo, JP;
Assignee:
Kabushiki Kaisha Toshiba, Tokyo, JP;
Primary Examiner:
Int. Cl.
CPC ...
H01L 3/10328 ; H01L 3/10336 ; H01L 3/1072 ; H01L 3/1109 ;
U.S. Cl.
CPC ...
H01L 3/10328 ; H01L 3/10336 ; H01L 3/1072 ; H01L 3/1109 ;
Abstract
A heterojunction bipolar transistor comprises, an emitter made of a first compound semiconductor of a first conductivity type; a base made of a second compound semiconductor of a second conductivity type and having a bandgap smaller than the first compound semiconductor; and a collector made of a third compound semiconductor of a first conductivity type and having a bandgap wider than the second compound semiconductor. The emitter and the base form a heterojunction of type I. The base and the collector form a heterojunction of type II. Further, the base includes impurities by a concentration equal to or more than 5×10 cm .