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:
Mar. 28, 2000
Filed:
Feb. 02, 1998
Takayuki Kamiya, Hamamatsu, JP;
Yamaha Corporation, , JP;
Abstract
A method of fabricating a multi power source semiconductor device handling multi-level voltages, comprises the steps of: forming first gate oxide layers by thermally oxidizing surfaces of the plurality of the active regions of said semiconductor substrate; forming a first mask having a window on a first active region among said plurality of the active regions of said semiconductor substrate; implanting impurity ions for controlling a threshold voltage, into a surface of said first active region through the first mask; removing the first gate oxide layer on the first active region exposed in the window of said first mask; removing said first mask; forming a thin second gate oxide layer on the first active region and a thick third gate oxide layer on a second active region different from the first active region among said plurality of the active regions by further thermally oxidizing the surfaces of the plurality of the active regions; forming on the semiconductor substrate a second mask having a window on the second active region; and implanting impurity ions for controlling a threshold voltage, into a surface of the second active region through said second mask. A method of fabricating a multi power source semiconductor device capable of realizing gate oxide layers of different thickness and different channel doping with a small number of masks is provided.