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:
Sep. 04, 2018
Filed:
Nov. 18, 2011
Michio Nemoto, Matsumoto, JP;
Haruo Nakazawa, Matsumoto, JP;
Michio Nemoto, Matsumoto, JP;
Haruo Nakazawa, Matsumoto, JP;
FUJI ELECTRIC CO., LTD., Kawasaki-Shi, JP;
Abstract
A semiconductor device is provided in which a semiconductor substrate can be prevented from being broken while elements can be prevented from being destroyed by a snap-back phenomenon. After an MOS gate structure is formed in a front surface of an FZ wafer, a rear surface of the FZ wafer is ground. Then, the ground surface is irradiated with protons and irradiated with two kinds of laser beams different in wavelength simultaneously to thereby form an Nfirst buffer layer and an N second buffer layer. Then, a P+ collector layer and a collector electrode are formed on the proton-irradiated surface. The distance from a position where the net doping concentration of the Nfirst buffer layer is locally maximized to the interface between the P+ collector layer and the N second buffer layer is set to be in a range of 5 μm to 30 μm, both inclusively.