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. 03, 1989
Filed:
Aug. 11, 1988
Applicant:
Inventors:
Shin-ichi Taka, Yokosuka, JP;
Jiro Ohshima, Kawasaki, JP;
Assignee:
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01L / ;
U.S. Cl.
CPC ...
437 33 ; 437 31 ; 437192 ; 437228 ; 148D / ; 148D / ; 357 34 ;
Abstract
A metal layer is formed by selective CVD method on an emitter region formed by using a field oxide film as a mask. Opening for ion-implanting an impurity for forming external base region is formed in the field oxide film by utilizing the metal layer and a metal layer creep up a bird's beak of the field oxide film as masks. An impurity is doped in a semiconductor substrate through the opening formed in the field oxide film to form external base region. The distance between the emitter region and external base region is controlled by a length of the metal layer creep up the bird's beak.