Analysis of carrier generation lifetime in strained-Si/SiGe heterojunction MOSFETs from capacitance transient

摘要

Carrier generation lifetime (tau(g)) in strained-Si/SiGe has been investigated using capacitance transient method in MOS structure. Interface properties of thermally grown gate oxide on strained-Si/SiGe has been studied prior to transient capacitance measurements. Average midgap value of interface state density (D-it) extracted from quasi-static CV measurement is around 2 x 10(10) to 5 x 10(10) cm(-2) eV(-1) for both strained-Si and bulk-Si samples. The observed non-linear behavior of capacitance transient characteristics for strained-Si/SiGe heterostructure are due to the carrier confinement in the potential wells caused by virtue of the valence band and conduction band discontinuities. Generation lifetime in strained-Si and SiGe buffer layer estimated from the segments of Zerbst plot having different slopes. The value of generation lifetime in strained-Si, SiGe buffer and co-processed bulk-Si is ranges from 120 to 170 mus, 20 to 90 mus and 177 mus, respectively. (C) 2003 Elsevier B.V. All rights reserved. [References: 18]