Degeneracy and High Doping Effects in Deep Sub-Micron Relaxed and Strained Si n-MOSFETs

Conventional scaling of modern semiconductor (MOSFET) devices to nano metre dimensions leads to ever-increasing doping levels both within the contacts (source and drain) and the channel region. Thus the carrier statistics governing the device operation become Fermi-Dirac in nature rather than Maxwell-Boltzmann. The effect of degeneracy becomes of even greater importance as strained materials such as strained-Si, are considered due to a decrease in the effective density of states. Additionally since the supply voltage does not scale as fast as the device dimensions, carrier transport takes place within a non-equilibrium/heated Fermi-Dirac distribution. Thus it is necessary to adopt simulation techniques such as ensemble Monte Carlo that includes non-equilibrium transport.