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

Carrier generation lifetime ( τ 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 2×10 10 to 5×10 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 μs, 20 to 90 μs and 177 μs, respectively.