Computer Simulation of a Nanoscale Ballistic SOI MOSFET with a Sub-10-nm Si Layer

A physical model and a computer simulation program for nanoscale ballistic SOI MOSFETs are developed. The model includes transistor parameters such as the type and level of doping in the source and drain regions, gate length, Si and gate-oxide thicknesses, spacer length, gate-material work function, etc. Transistor performance is characterized in terms of transconductance, subthreshold slope, on- and off-state drain currents, gate–source overlap capacitance, etc. The software enables one to optimize the transistor parameters.     

Effect of Surface Roughness on Quantum Carrier Transport in Ultrathin Films

A theoretical study is reported of the carrier transport in an ultrathin metal film and a quantum-well layer subject to scattering by surface irregularities. A consistent quantum-mechanical approach to the problem is developed. Power-law approximations with different exponents are obtained to the conductivity–thickness relationship. The results are compared with previously published experimental data.     

Monte Carlo Simulation of Nanoscale SOI MOSFETs

A comparative review is presented of the current research on the quantum-mechanical and classical Monte Carlo simulation of SOI MOSFETs. A quantum-mechanical simulation method is proposed whereby the energy of transverse channel quantization is represented by a correction term. A newly developed simulation program, called BALSOI, is outlined. A comparison is made between the results of a 2D classical Monte Carlo simulation and those obtained by the quantum-mechanical method. It is observed that the differences are much smaller than what one might expect. This finding is explained as due to the considerable effect of the space charge, which is mainly governed by the classical, longitudinal motion of carriers through the channel. An analytical formula is derived for the effect of channel quantization on the gate–channel capacitance. The strength of tunneling current through a short-channel transistor in the off state is considered.