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:
Feb. 02, 2010
Filed:
Sep. 19, 2007
Tsunehiro Ino, Fujisawa, JP;
Kouichi Muraoka, Sagamihara, JP;
Tsunehiro Ino, Fujisawa, JP;
Kouichi Muraoka, Sagamihara, JP;
Kabushiki Kaisha Toshiba, Tokyo, JP;
Abstract
A nonvolatile semiconductor memory device includes: a source region and a drain region formed at a distance from each other in a semiconductor substrate; a tunnel insulating film formed on the semiconductor substrate between the source region and the drain region; a charge storage film formed on the tunnel insulating film; a first alumina layer formed on the charge storage film, and having a first impurity element added thereto, the first impurity element having an octacoordinate ion radius of 63 pm or greater, the first impurity element having a concentration distribution in a layer thickness direction of the first alumina layer that becomes the largest in a region close to the side of the charge storage film; a second alumina layer formed on the first alumina layer, and not having the first impurity element added thereto; and a control gate electrode formed on the second alumina layer.