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:
Sep. 18, 1990
Filed:
Aug. 08, 1988
Shin-Ichi Tanaka, Tokyo, JP;
NEC Corporation, , JP;
Abstract
There is disclosed a heterojunction bipolar transistor comprising an emitter region having a first conductivity type, a base region having a second conductivity type opposite to the first conductivity type, and a collector region having a graded collector section formed of a first compound semiconductor material and a collector contact section formed of a second compound semiconductor material of the first conductivity type, and an emitter-base junction, a base-collector junction and an abrupt potential discontinuity are formed between the emitter region and the base region, between the base region and the graded collector section and between the graded collector section and the collector contact section, respectively, wherein the first compound semiconductor material is increased in bandgap from the base-collector junction toward the collector contact section and the second semiconductor material is smaller in bandgap at the abrupt junction than the first semiconductor material, so that the potential difference between the base region and the collector region is compensated by the abrupt potential discontinuity, thereby restricting the production of hot electrons.