Degradation phenomena of tunnel oxide floating gate EEPROM devices

The degradation of tunnel oxide floating gate EEPROM devices was studied by using charge-pumping which allows direct characterization of the interface degradation on the transistor itself. It is found that positive charge is generated at the Si-SiO2 interface, while negative charges are trapped at the injecting interface or in the bulk of the oxide. Combining these findings with a study of the influence of the charges present in the oxide and at the interfaces on injection and threshold voltage, it is possible to explain qualitatively all measured degradation characteristics.