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. 14, 1990
Filed:
Oct. 04, 1988
Kazuo Yano, Koganei, JP;
Masaaki Aoki, Minato, JP;
Toshiaki Masuhara, Nishitama, JP;
Katsuhiro Shimohigashi, Musashimurayama, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
In a homo-junction bipolar transistor suitable for a low temperature operation below 200.degree.K. (particularly below 77 K), the maximum value of the impurity concentration of an intrinsic base region is set to be at least 1.times.10.sup.18 /cm.sup.3. The impurity concentration of an emitter region is set to a value lower than this maximum value. Thus, a base resistance can be reduced and high speed operation becomes possible. Furthermore, bandgap narrowing develops in the intrinsic base region and a common-emitter current gain in the low temperature operation can be kept at a sufficient value. When this homo-junction bipolar transistor is formed together with complementary insulated gate field effect transistors on the surface of a semiconductor substrate, there can be obtained a Bi-CMOS device capable of a high speed operation even in the low temperature operation.