Electron mobility of strained InGaAs long-channel MOSFETs: From scattering rates to TCAD model

Abstract

TCAD modelling of InGaAs channel MOSFETs is a complex task due to the combined effect of quantization and interface or border traps, which affect the device electrostatics as well as the electron mobility through Coulomb scattering. In addition, trap distributions and mobility are strain-dependent. In this paper, we start from a microscopic physical approach, based on the use of Sentaurus SBand by Synopsys as 1D Schrödinger-Poisson solver and mobility calculator through the Kubo-Greenwood (KG) approach, to end up with a TCAD modelling framework that combines the Density Gradient (DG) model for quantum corrections with simple empirical expressions for the mobility model. Only the long-channel (or low-field) mobility is addressed. A distinctive feature of the paper is the use of experimental Hall electron density and mobility data as a reference for the calibration of interface traps and scattering rates in SBand. SBand simulation results for different strain levels and layer thicknesses are then used as the basis for the TCAD model calibration (DG and mobility). Our findings indicate that strain can increase mobility mainly through the reduction of Coulomb scattering with trapped charge.