With the charge pumping technique, the role of hot holes in the channel hot carrier degradation of short channel n-MOS transistors is shown to be less pronounced at 77 K than at 300 K. Also fewer fast interface states are generated at 77 K for the same substrate current level in the low gate bias regime. Furthermore, the dominant device degradation is found to be in the high gate bias regime at 77 K, in contrast to the case of 300 K. This is due to the presence of negative charge in the oxide or in acceptor-type interface states.