Evaluation of hole mobility degradation by remote Coulomb scattering in Ge pMOSFETs

摘要

This paper presents a comprehensive, numerical simulation of the remote Coulomb scattering (RCS) in Ge pMOSFETs due to interfacial charges and dipole in the gate stack. Hole mobility is calculated using a relaxation time approximation that consistently accounts for intra and intersubband transitions and multisubband transport. Our results show that the RCS appreciably degrades the hole mobility at both low and high electric field region. Especially the remote dipole scattering plays a main role on the RCS. Moreover, we discuss the dependence of hole mobility on interlayer GeO2 thickness, and possible benefits in terms of the RCS limited mobility by using an interlayer with higher dielectric constant.