Distributive Quasi-Ballistic Drift Diffusion Model Including Effects of Stress and High Driving Field

This paper presents a simulation study using a novel distributive quasi-ballistic drift diffusion (DD) TCAD model applied to low mobility unstressed and high mobility stressed scaled pMOS devices. The model is implemented in a DD simulator and used to study the gate length dependence of current drives. The new model captures the physically correct potential distribution and gives the correct drive current limit in ballistic devices for both linear current response and current saturation source-drain bias conditions. The diffusive and ballistic transport is connected using a ballistic probability, which relates to the fundamental time scale in the problem-the mean energy relaxation time. The model captures the ballistic velocity degradation from the diffusive limit at linear source-drain biases. It is shown that the DD simulation with the distributive quasi-ballistic model describes the stress ballistic drive gains at high driving field, which are missed by the existing ballistic models.