TW262591B - Process of flash EEPROM memory cell - Google Patents

Abstract

A process of flash EEPROM memory cell, that is applicable fabricate flash EEPROM memory cell on substrate, includes the following steps: (1) doping dopant to the above substrate to form the first doped region; (2) forming trench on predetermined position of the above substrate to make the above first doped region form source and drain region separately; (3) forming gate oxide on the above trench and substrate; (4) forming masking material on gate oxide in the above trench to expose gate oxide located on the above source and drain region; (5) with the above masking material as mask removing gate oxide located on the above source and drain region; (6) with the above masking material as mask forming tunnel oxide on the above source and drain region, and the thickness of the above tunnel oxide is less than the above gate oxide's; (7) removing the above masking material; (8) forming floating gate on the above tunnel oxide and gate oxide; (9) forming dielectric layer and control gate between gates on the above floating gate in sequence.