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:
Oct. 25, 1988
Filed:
Nov. 12, 1987
Teruo Tabata, Gumma, JP;
Sanyo Electric Co., Ltd., , JP;
Abstract
The present invention relates to a semiconductor device and a method of producing the same. According to this method, a lower diffusion layer of a double isolation diffusion area is attached to a surface of a substrate, an epitaxial layer being formed on the lower diffusion layer, the lower diffusion layer being largely outdiffused upwardly in the epitaxial layer and simultaneously an element diffusion area being deeply diffused from a surface of the epitaxial layer, and then an upper diffusion layer of the double isolation diffusion area being shallowly diffused from the surface of the epitaxial layer. Thus, the lateral expansion of the upper diffusion layer of the double isolation diffusion area can be suppressed and the integrated extent can be improved. On the other hand, in a semiconductor device of the present invention, the above described double isolation diffusion area is formed and a collector area, a base area and an emitter area are formed all over the width of the epitaxial layer (the base area and the emitter area are formed by a double diffusion). In addition, it includes a vertical type transistor whose fluctuation of a width of the base area is reduced, so that the transition frequency f.sub.T and current gain h.sub.FE of this transistor are increased.