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:
Jul. 19, 1994
Filed:
Feb. 12, 1993
Yasukazu Mukogawa, Hyogo, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
A semiconductor substrate allowing prevention of the breakdown voltage degradation of a gate oxide film and having a prescribed mechanical strength in order to cope with increase in the diameters of wafers corresponding to reduction in the dimensions of semiconductor devices and improvement in productivity, and a Bi-CMOS semiconductor device allowing electrical characteristics to be maintained in any of a bipolar transistor and a field effect transistor are provided. An epitaxial layer is formed on a silicon wafer formed by means of CZ method. A silicon wafer formed by means of FZ method is joined onto the epitaxial layer. An npn bipolar transistor is formed in the epitaxial layer. An n channel MOS transistor and a p channel MOS transistor are formed in the silicon wafer.