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. 11, 2013
Filed:
Dec. 15, 2011
Yue Xu, Jiangsu, CN;
Feng Yan, Jiansu, CN;
Ling Pu, Jiangsu, CN;
Xiaoli Ji, Jiangsu, CN;
Nanjing University, Nanjing, Jiangsu, CN;
Abstract
A localized trapping multi-level memory cell operating method includes the following steps. First, a localized trapping memory cell with the initial threshold voltage of approximately 2.5V is provided. Next, an erasing operation is performed to obtain a negative threshold level having uniform charge distribution along the channel region. Taking into account the over-erasure issue in the erasing operation, a programming operation is performed to precisely adjust the threshold voltage to a predetermined level of −2V to −1V. Then, with this negative voltage as a new initial state, a corresponding programming operation is performed and electrons are locally injected into the storage layer. By controlling the quantity of injected electrons, the MLC storage is achieved.