Effect of access resistance on apparent mobility reduction in nano-MOSFET

Thanks to both device simulation and ballistic calculation, the concept of apparent mobility is discussed in the case of unstrained and strained nanoscale DG MOSFET. We show that the apparent mobility reduction in simulated short channel devices can be explained by non stationary effects. The apparent mobility is successfully linked to the long-channel mobility and to a ldquoballistic mobilityrdquo using a Mathiessen´s rule. Moreover, a simple extended expression of the ballistic mobility in the Shur analytical model suggests the non-universal nature of this parameter through its dependence on drain voltage, access resistance and device geometry. The effect of access resistance is analyzed in more details by means of ballistic calculations. The results are consistent with that obtained from both Monte Carlo simulation and measurements.