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. 07, 2019
Filed:
Dec. 26, 2017
Toshiba Memory Corporation, Minato-ku, JP;
Naoki Yasuda, Mie, JP;
TOSHIBA MEMORY CORPORATION, Minato-ku, JP;
Abstract
A semiconductor memory device includes a plurality of electrode layers stacked in a first direction; a semiconductor layer of a columnar shape extending through the electrode layers in the first direction; and a plurality of floating gates provided between the electrode layers and the semiconductor layer respectively. The floating gates surround the semiconductor layer. A gate length in a first direction of a floating gate positioned between one of the electrode layers and the semiconductor layer is longer than a layer thickness in the first direction of the one of the electrode layers. A ratio of the layer thickness of the one of the electrode layers to the gate length has a positive correlation with an outer diameter of a first portion of the semiconductor layer surrounded by the floating gate in a second direction from the semiconductor layer toward the one of the electrode layers.