Hot Carrier Degradation in Si n-MOSFETs at Cryogenic Temperatures

This study experimentally investigated hot carrier degradation (HCD) in Si-MOSFETs at cryogenic temperatures. Stress was applied to the devices at 4 K and 300 K, followed by temperature-dependent characterization from 4 K to 300 K to evaluate the degradation mechanism. The results indicated that at 4 K, the effect of HCD on current-voltage characteristics is attributable to band-edge states, whereas at 300 K, it is primarily due to deep states. Despite the temperature at which HCD occurred, both states are induced simultaneously by hot carriers. Deuterium termination of dangling bonds mitigates HCD even at 4 K, where degradation is caused by band-edge states. These results suggest that the band-edge states and deep states should be considered in conjunction, rather than in isolation, to fully understand the degradation behavior.