NEW EXPERIMENTAL FINDINGS ON HOT-CARRIER EFFECTS IN SUB-0.1 MU-M MOSFETS

The behaviors of the substrate current and the impact ionization rate are investigated for deep submicron devices in a wide temperature range. New important features are shown for the variations of the maximum substrate current as a function of applied biases and temperature. It is found that the gate voltage V (g) (max), corresponding to the maximum impact ionization current conditions, is quasi-constant as a function of the drain bias for sub-0.1 mu m MOSFET's in the room temperature range. At low temperature, a substantial increase of V (g) (max), is observed when the drain voltage is reduced. It is also shown that, although a significant enhancement of hot carrier effects is observed by scaling down the devices, a strong reduction of the impact ionization rate is obtained for sub-0.1 mu m M0SFET's operated at liquid nitrogen temperature in the low drain voltage range.