A non-isothermal device simulator for MOSFET analysis

A nonisothermal semiconductor device simulator is developed which solves not only the conventional drift-diffusion equations but also the energy balance and heat flow equations to account for nonequilibrium transport phenomena and lattice temperature effects. The results are compared with the conventional drift-diffusion model. In order to reduce computation time, the heat flow equation is solved by an iterative scheme where this equation is solved only once during three cycles of the iteration loop. It is found that heat generation abruptly increases in the vicinity of the drain and the channel interface, and the lattice temperature shows a localized increase of about 20° in a MOSFET with a channel length of 0.3 μm, under a bias of V_G= V_D=3.0 V. The electron density distribution spread is broader than with that of the drift-diffusion model-that is, the channel depth becomes wider than in a conventional case