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:
Mar. 31, 1992
Filed:
Jul. 31, 1991
Makoto Yoshimi, Tokyo, JP;
Minoru Takahashi, Yokohama, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
On the surface of an insulating substrate, a semi-conductor layer composed of a semiconductor layer of a first conductivity type on which a high-concentration semiconductor layer of the first conductivity type is formed. By selectively etching the semiconductor layer, the high-concentration external base region of the first conductivity is left, and at the same time, only a thicker prospective internal base region just under the external base region and a prospective emitter region and prospective collector region, which are located on both sides of the prospective internal base region and have steps between themselves and the prospective internal base region, are left to form island regions. A sidewall insulating film is formed which covers at least the sidewalls on the prospective collector region side among sidewalls of the external base region and sidewalls at the steps of the prospective internal base region adjoining the sidewalls of the external base region. The emitter region and collector region of the second conductivity type are formed by ion implantation perpendicular to the substrate with the insulating film covering the external base region and the sidewall insulating film as blocking mask.