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:
Jul. 18, 2000
Filed:
Jan. 21, 1999
Marco Pasotti, S. Martino Siccomario, IT;
Roberto Canegallo, Tortona, IT;
Ernestina Chioffi, Pavia, IT;
Giovanni Guaitini, Trecella, IT;
Frank Lhermet, Vimercate, IT;
Pierluigi Rolandi, Monleale, IT;
STMicroelectronics, S.r.l., Agrate Brianza, IT;
Abstract
The controlled erase method includes supplying at least one erase pulse to cells of a memory array; comparing the threshold voltage of the erased cells with a low threshold value; selectively soft-programming the erased cells which have a threshold voltage lower than the low threshold value; and verifying whether the erased cells have a threshold voltage lower than a high threshold value, which is higher than the low threshold value. If at least one predetermined number of erased cells has a threshold voltage which is higher than the high threshold value, an erase pulse is applied to all the cells and the steps of comparing, selectively soft-programming and verifying are repeated.