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. 13, 2018
Filed:
Oct. 26, 2016
Toshiba Memory Corporation, Minato-ku, JP;
Naoki Yasuda, Yokohama, JP;
Masaru Kito, Kuwana, JP;
TOSHIBA MEMORY CORPORATION, Minato-ku, JP;
Abstract
A nonvolatile semiconductor storage device having a control gate formed on a semiconductor substrate and including a cylindrical through hole. A block insulating film, a charge storage film, a tunnel insulating film, and a semiconductor layer are formed on a side surface of the control gate inside the through hole. The tunnel insulating film includes a first insulating film having SiOas a base material and containing an element that lowers a band gap of the base material by being added. A density and a density gradient of the element monotonously increase from the semiconductor layer toward the charge storage film.