Microscopic Modeling of Surface Roughness Scattering in Inversion Layers of MOSFETs Based on Ando's Linear Model

TL;DR

This paper introduces a microscopic model for surface roughness scattering in MOSFET inversion layers based on Ando's linear model, aligning theory with experimental parameters.

Contribution

It develops a nonlocal scattering rate model using Green's functions that accounts for stochastic roughness and deviates from traditional Fermi's golden rule predictions.

Findings

The model's parameters match experimental data.

The scattering rate is intrinsically nonlocal and subband-dependent.

Self-consistent scattering rates differ significantly from traditional models.

Abstract

A microscopic model of surface roughness (SR) scattering in inversion layers of bulk-MOSFETs based on Ando's linear model is proposed. Taking into account the stochastic nature of roughness position induced by discontinuity of the spatial derivatives of electrostatic potential and wave-function at the semiconductor/dielectric interface, a probability density of roughness position is introduced at each atomic site. The roughness parameters in the proposed model are consistent with those from experiments, and thus, there is no discrepancy between theory and experiment. The SR scattering rate is then derived by using the Green's function scheme, and we find that the scattering rate is intrinsically nonlocal (nondiagonal) with respect to subband indices and position. In addition, the self-consistent scattering rate greatly deviates from those obtained by Fermi's golden rule in the regimes of strong effective fields and low electron energies. As a result, the conventional model tends to predict smaller SR-limited mobility.