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:
Aug. 03, 2004
Filed:
Feb. 14, 2003
Nobuyo Sugiyama, Hyogo, JP;
Hiromasa Fujimoto, Kyoto, JP;
Shinji Odanaka, Osaka, JP;
Seiki Ogura, Wappingers Falls, NY (US);
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
A nonvolatile semiconductor memory device according to the present invention has a control gate electrode which is formed on the upper stage of a stepped portion formed in the principal surface of a substrate with a first insulating film interposed therebetween and a floating gate electrode which is formed to cover up the stepped portion, capacitively coupled to the side surface of the control gate electrode closer to the stepped portion with a second insulating film interposed therebetween, and opposed to the lower stage of the stepped portion with a third insulating film serving as a tunnel film interposed therebetween. Within the semiconductor substrate and in the vicinity of the stepped portion, there is formed a depletion control layer which is composed of a heavily doped impurity region and formed to extend from a position located under the floating gate electrode and at a distance from the upper corner of the stepped portion toward the lower corner of the stepped portion and adjoin the end portion of a drain region without reaching a step side region.