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:
Nov. 26, 2019
Filed:
Jul. 06, 2017
Renesas Electronics Corporation, Tokyo, JP;
Kazuya Horie, Hitachinaka, JP;
Katsuhiro Uchimura, Hitachinaka, JP;
Kazuhiro Toi, Hitachinaka, JP;
Masakazu Nakano, Hitachinaka, JP;
RENESAS ELECTRONICS CORPORATION, Tokyo, JP;
Abstract
In manufacturing a trench type MOSFET, reliability of a semiconductor device is prevented from being degraded due to a short circuit or lowering of withstand voltage between a trench gate electrode and a source region. To achieve the above, poly-silicon films are formed inside a trench in a main surface of a semiconductor substrate and over the semiconductor substrate. Further, phosphorus is thermally diffused into each poly-silicon film from a phosphorous film over an upper surface of the poly-silicon film. Still further, a silicon oxide film formed in a surface layer of the poly-silicon film by the thermal diffusion process is removed by a first dry etching process using a fluorocarbon gas or a hydroxy-fluorocarbon gas. Then, by performing a second dry etching process using a Cl2 gas etc., an insulating film is exposed and, thereby, a trench gate electrode including the poly-silicon film is formed.