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. 27, 1999
Filed:
Apr. 16, 1998
Minoru Kawakami, Tokyo, JP;
Mitsuhiro Yano, Tokyo, JP;
Yasunori Yamashita, Tokyo, JP;
Hidetoshi Souno, Hyogo, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Ryoden Semiconductor System Engineering Corporation, Itami, JP;
Abstract
An n.sup.+ semiconductor substrate (1) using a silicon wafer as a base material and including As includes oxygen of which the concentration is in the range of 12E17 atoms/cm.sup.3 to 20E17 atoms/cm.sup.3. The first epitaxial growth layer (2) of n type and a diffusion layer (3) of p type are formed in sequence on the second major surface (1S2) of the semiconductor substrate (1). The thickness of an epitaxial a growth layer (10) is set to be not more than 20 .mu.m. A trench (6) is formed so as to extend from a surface of the diffusion layer (3) to the inside of the first epitaxial growth layer (2). A gate oxide film (5) is formed on a bottom surface (6B) and a wall surface (6W) of the trench (6) and a conductive layer (11) fills the trench (6). An n-type source layer (4) is formed at a corner (6C) of the trench (6). After that, predetermined electrodes are formed and so on, to complete a device. With this structure, it is possible to reduce a leak current, prevent deterioration in main breakdown voltage and stabilize gate-oxide-film breakdown-voltage characteristics in a vertical MOSFET with trench gate.