In this paper we present a methodology to use drift diffusion (DD) simulations in the
design of short channel heterojunction FETs (HFETs) with well pronounced velocity
overshoot. In the DD simulations the velocity overshoot in the channel is emulated by
forcing the saturation velocity in the field dependent mobility model to values
corresponding to the average velocity in the channel obtained from Monte Carlo (MC)
simulation. To illustrate our approach we compare enhanced DD and MC simulation
results for a pseudomorphic HEMTs with 0.12 μm channel length, which are in good
agreement. The usefulness of the described methodology is illustrated in a simulation
example of self aligned gamma gate pseudomorphic HEMTs. The effect of the gamma
gate shape and the self aligned contacts on the overall device performance has been
investigated.
Monte Carlo Calibrated Drift-Diffusion Simulation
of Short Channel HFETs
