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:
Jun. 04, 1991
Filed:
Nov. 09, 1989
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
In a high-frequency amplifying semiconductor device in which a MOS field effect transistor and a bipolar transistor are formed within the same wafer and a source electrode of the MOS field effect transistor is connected to a lead frame by a bonding wire, use is made of a wafer for fabricating the MOS field effect transistor and the bipolar transistor, in which on a semiconductor substrate of P++ type is formed a first epitaxial layer of P or P- type, a buried layer of N+ type is formed in the first epitaxial layer of the first conductivity type and a second epitaxial layer of P type is formed on the buried layer and the first epitaxial layer. The use of such a wafer, which has no P- type Si substrate, allows the source resistance of the MOS field effect transistor to be decreased. The high-frequency amplifying semiconductor device is improved in high-frequency gain and NF.