A unified density gradient approach to ‘ab-initio’ ionised impurity scattering in 3D MC simulations of nano-CMOS variability

A methodology for incorporating quantum corrections into self-consistent atomistic Monte Carlo (MC) simulations via the density gradient effective potential is presented. The quantum corrections not only capture charge confinement effects, but accurately represent the electron-impurity interaction used in previous dasiaab initiopsila atomistic MC simulations, showing agreement with bulk mobility simulation. The effect of quantum corrected transport variation in statistical atomistic MC simulation is then investigated using a series of realistic scaled devices. Increased current variation is observed compared with quantum corrected drift diffusion simulation and with previous classical MC results.