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:
Jun. 06, 1995
Filed:
Nov. 23, 1993
Koji Shirai, Kawasaki, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
A field effect transistor comprises a first conductive type semiconductor substrate, a second conductive type source region formed on the semiconductor substrate, a second conductive type drain region formed on the semiconductor substrate and non-contacting the source region, and a gate electrode formed on a channel region between the source region and the drain region through a gate insulating film, wherein the thickness of the gate insulating film is thickened at least in a two-step manner in a direction from the source region to the drain region, impurity concentration of the respective channel regions under the gate insulating film having a different film thickness is different, and impurity concentration of the channel region under the thick film portion of the gate insulating film is lower than that of the channel region under the thin film portion of the gate insulating film.