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:
Aug. 30, 1988
Filed:
Oct. 13, 1987
Jiro Yoshida, Yokohama, JP;
Makoto Azuma, Yokohama, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
A heterojunction bipolar transistor comprises a base region of a first conductivity type formed of a first kind of semiconductor material, an emitter region of a second conductivity type formed of a second kind of semiconductor material which has a band gap greater than that of the first kind of semiconductor material and a smaller electron affinity, a transition region formed between the base region and the emitter region, and a collector region formed adjacent to the base region. The transition region is formed of a plurality of semiconductor layers such that band gaps sequentially increase in a stepped fashion from the semiconductor layer adjacent to the base region toward the semiconductor layer adjacent to the emitter region. The transition region is formed of a semiconductor material having an intermediate composition between the composition of the first kind of semiconductor material and that of the second kind of semiconductor material.