We propose a model for partially ballistic MOSFETs and for channelbackscattering that is alternative to the well known Lundstrom model and ismore accurate from the point of view of the actual energy distribution ofcarriers. The key point is that we do not use the concept of "virtual source".Our model differs from the Lundstrom model in two assumptions: i) thereflection coefficients from the top of the energy barrier to the drain andfrom top of the barrier to the source are approximately equal (whereas in theLundstrom model the latter is zero), and ii) inelastic scattering is assumedthrough a ratio of the average velocity of forward-going carriers to that ofbackward-going carriers at the top of the barrier kv > 1 (=1 in the Lundstrommodel). We support our assumptions with 2D full band Monte Carlo (MC)simulations including quantum corrections in nMOSFETs. We show that our modelallows to extract from the electrical characteristics a backscatteringcoefficient very close to that obtained from the solution of the Boltzmanntransport equation, whereas the Lundstrom model overestimates backscattering byup to 40%.
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