Trap generation during low-fluence avalanche-electron injection in metal-oxide-silicon capacitors

Abstract
Trap generation during low-fluence avalanche-electron injection (AEI) in metal-oxide-silicon capacitors (MOSC’s) with different fabrication processing cycles was investigated. Injection gate voltages from 45 to 65 V for an oxide of 1000 Å thickness were used to simulate hot-electron effects in oxidized silicon under transistor operation conditions. Experimental results indicate that more negatively charged traps are generated in wet oxide than dry oxide. Different trap-generation phenomena in poly-Si- and aluminum-gate MOSC’s were observed. The midgap voltage shift of aluminum-gate MOSC during AEI is not appreciably dependent on the magnitude of the peak AEI voltage, while that of poly-Si-gate MOSC has a strong dependence. The generation rate of interface states in aluminum-gate MOSC is much smaller than that of poly-Si-gate MOSC. The results are interpretable by the hydrogen model.