Model Extraction for Body-Biased XDMOS Devices

Introduction

Compared with regular MOSFET devices, the body bias effect in HVMOS is usually more pronounced. In addition to the regular threshold voltage increase with body bias, the LDD region of the HVMOS typically also has a significant body bias dependence. Also, the VBS dependence of mobility degradation with the transversal electric field needs to be taken into account. Due to these particularities, modeling of HVMOS devices with body contact requires careful consideration of body bias dependencies. Semi-empirical compact models make use of extra model parameters in order to achieve the needed body bias dependence accuracy. In the case of physics-based compact models, such as HiSIM_HV2, the effect of body bias can be naturally and accurately considered, with very few such extra parameters.

This paper illustrates a model extraction methodology for body-biased extended drain MOSFET (XDMOS) devices, using the standard compact HVMOS model HiSIM_HV2, Version 2.3.1. The model calculates the device currents by solving the Poisson equation of the surface potential, so the body bias effect is implicitly considered up to a reasonable degree of accuracy. In case higher accuracy is required, two extra model parameters are available: SC3, which considers the VBS dependence of the threshold voltage short-channel effect, and MUEEFB, introduced in Version 2.3.0 to account for the VBS dependence of phonon scattering.