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. 16, 2014
Filed:
Nov. 13, 2013
Fuji Electric Co., Ltd., Kawasaki, JP;
Yoshiaki Toyoda, Matsumoto, JP;
Takatoshi Ooe, Matsumoto, JP;
Fuji Electric Co., Ltd., Kawasaki-Shi, JP;
Abstract
A method of forming a device in each of vertical trench gate MOSFET region and control lateral planar gate MOSFET region of a semiconductor substrate is disclosed. A trench is formed in the substrate in the vertical trench gate MOSFET region, a first gate oxide film is formed along the internal wall of the trench, and the trench is filled with a polysilicon film. A LOCOS oxide film is formed in a region isolating the devices. A second gate oxide film is formed on the substrate in the lateral planar gate MOSFET region. Advantages are that number of steps is suppressed, the gate threshold voltage of an output stage MOSFET is higher than the gate threshold voltage of a control MOSFET, the thickness of the LOCOS oxide film does not decrease, and no foreign object residue remains inside the trench.