HOT-CARRIER EFFECTS IN SUB-0.1 MU-M GATE LENGTH MOSFETS BETWEEN ROOM AND LIQUID-HELIUM TEMPERATURES

The variations of the substrate current and the impact ionization rate in MOS transistors are investigated as a function of channel length a nd temperature. It is shown that, although a significant enhancement o f hot carrier effects is observed by scaling down the devices, a stron g reduction of the impact ionization rate is obtained for sub-0.1 mum MOSFETs operated at liquid nitrogen temperature in the low drain volta ge range. A thorough study of the electrical properties of these deep submicron devices allows us to gain insight in the physical mechanisms involved in the hot carrier transport in a wide temperature range.