HOT-CARRIER EFFECTS AND LIFETIME PREDICTION IN OFF-STATE OPERATION OFDEEP-SUBMICRON SOI N-MOSFETS

Hot-carrier effects (HCE) induced by the parasitic bipolar transistor (PBT) action are thoroughly investigated in deep submicron N-channel S OI MOSFET's for a wide range of temperature and gate length. A multist age device degradation is highlighted for all the experimental conditi ons. Original V-t variations are also obtained for short-channel devic es, a reduction of the threshold voltage being observed for intermedia te values of stress time in the case of high stress drain biases. At l ow temperature (LT), an improvement of the device aging can be obtaine d in the low V-d range because of the significant reduction of the lea kage current in the PET regime. However, in the case of high V-d, sinc e the strong leakage current cannot be suppressed at LT, the device ag ing is larger than that obtained at room temperature. On the other han d, the device lifetime in off-state operation is carefully predicted a s a function of gate length with various methods. Numerical simulation s are also used in order to propose optimized silicon-on-insulator (SO I) architectures for alleviating the PET action and improving the devi ce performance and reliability.