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 A˚ 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.