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. 21, 1998
Filed:
Jul. 03, 1995
Jonathan Lin, Milpitas, CA (US);
Stewart Logie, Campbell, CA (US);
Advanced Micro Devices, Inc., Sunnyvale, CA (US);
Abstract
An improved EEPROM structure is provided which has a longer data retention period. This is achieved by utilizing only positive charges to store data on the floating gate. The EEPROM structure includes a write select transistor (112), a read select transistor (120), and a floating gate sense transistor (126). The source of the write select transistor is capacitively coupled to the floating gate of the floating gate sense transistor via a tunnel oxide layer (145). The floating gate of the floating gate sense transistor is also capacitively coupled to a control gate line (CG) via a gate oxide layer (153). The sense transistor is formed as an enhancement transistor so as to allow the EEPROM structure to be operated in a region where the floating gate potential is positive for both programmed and erased conditions, thereby using only the positive charges to store data.