MOS device modeling at 77 K

The state of the art in self-consistent numerical low-temperature MOS modeling is reviewed. The physical assumptions that are required to describe carrier transport at low ambient temperatures are discussed. Particular emphasis is placed on the models for space charge (impurity freeze-out), carrier mobility (temperature dependence of scattering mechanisms at a semiconductor-insulator interface), and carrier generation-recombination (impact ionization). The differences with regard to the numerical methods required for the solution of low-temperature models compared to room-temperature models are explained. Typical results obtained with the simulator MINIMOS 4 are presented. These include comparisons of short-channel effects and hot-electron phenomena such as energy relaxation and avalanche breakdown at 77 K and 300 K ambient temperatures