Use of process and 2-D MOS simulation in the study of doping profile influence on S/D resistance in short channel MOSFET´s

At small VDS, gmreduction in MOSFET´s is often attributed to mobility degradation due to increased vertical electric field with increasing VGS. This is correct for long channel devices; however, for short channel devices the parasitic series resistance of source/drain, RT, has a similar effect in reducing the gmvalue. In this paper, simulation is used to show how the lateral subdiffusion regions of S/D represent a dominant, VGS-dependent portion of the total resistance, since the doping profile there is steeply decreasing and the carrier concentration can be modulated by the gate voltage.