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:
Apr. 25, 2000
Filed:
Oct. 24, 1997
Ming-Chou Ho, Taichang, TW;
Jian-Hsing Lee, Hsin-chu, TW;
Kuo-Reay Peng, TarnySan, TW;
Juang-Ke Yeh, Hsin-Chu, TW;
Taiwan Semiconductor Manufacturing Company, Ltd., Hsin-Chu, TW;
Abstract
A method to erase data from a flash EEPROM while electrical charges trapped in the tunneling oxide of a flash EEPROM are eliminated to maintain proper separation of the programmed threshold voltage and the erased threshold voltage after extended programming and erasing cycles, while preventing damage due to high field stress in the tunneling oxide. The method to erase a flash EEPROM cell begins by applying a relatively high positive voltage pulse to the source of the EEPROM cell. Simultaneously a ground reference voltage is applied to the drain and to the semiconductor substrate. At the same time a relatively large negative voltage pulse is applied to the control gate. This will cause a parasitic bipolar transistor to conduct and go into a snap back condition reducing the voltage field in the tunneling oxide.