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:
Dec. 30, 2003
Filed:
Aug. 02, 2002
Michio Nemoto, Nagano, JP;
Tatsuya Naito, Nagano, JP;
Masahito Otsuki, Nagano, JP;
Mitsuaki Kirisawa, Nagano, JP;
Fuji Electric Co., Ltd., Kawasaki, JP;
Abstract
A high-speed, soft-recovery semiconductor device that reduces leakage current by increasing the Schottky ratio of Schottky contacts to pn junctions. In one embodiment of the present invention, an n drift layer is formed on an n cathode layer by epitaxial growth, and ring-shaped ring trenches having a prescribed width are formed in the n drift layer. Oxide films are formed on the side walls of each ring trench. The ring trenches are arranged such that the centers of the rings of the ring trenches adjacent to one another form a triangular lattice unit. A p anode layer is formed at the bottom of each ring trench. Schottky contacts are formed at the interface between an anode electrode and the surface of the n drift layer. Ohmic contact is established between the surfaces of polysilicon portions and the anode electrode.