The Search for Cathode and Anode Traps in High-Voltage Stressed Silicon Oxides

When silicon oxide is stressed at high voltage, traps are generated inside the oxide and at the oxides interfaces. The traps are negatively charged neat the cathode and positively charged near the anode. The charge state of the traps can be easily changed. Several models of trap generation have been proposed. These models involve either electron impact ionization processes or high field generation processes. We have attempted to determine the relative trap locations inside the oxides for oxides between 5 nm and 80 nm thick. No evidence for a higher density of traps near the anode in any of these oxides was found, casting doubt on the efficiency of the impact ionization processin trap generation, even in thicker oxids. This data would supporto a trap generation model controled by the high fields inside the oxides