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:
May. 19, 2020
Filed:
May. 01, 2014
Renesas Electronics Corporation, Tokyo, JP;
RENESAS ELECTRONICS CORPORATION, Tokyo, JP;
Abstract
In a semiconductor device (MISFET) having a gate electrode formed over a nitride semiconductor layer with a gate insulating film interposed therebetween, the gate insulating film includes a first gate insulating film (oxide film of first metal) formed on the nitride semiconductor layer and a second gate insulating film (oxide film of second metal). The second metal (for example, Hf) has electronegativity lower than that of the first metal (for example, Al). Since the electronegativity of the second metal is lower than that of the first metal, negative charge is introduced into the oxide film of the first metal due to interfacial polarization, so that the flat-band voltage can be shifted in a positive direction. Accordingly, the threshold voltage which has become negative due to the heat treatment of the oxide film of the first metal can be shifted in the positive direction.