Strained-Si pMOSFETs on Very Thin Virtual SiGe Substrates

Strained-Si pMOSFETs on very thin relaxed virtual SiGe substrates are presented.The 240nm relaxed virtual Si0.8Ge0.2 layer on 100nm low-temperature Si(LT-Si) is grown on Si(100) substrates by molecular beam epitaxy.LT-Si buffer layer is used to release stress of the SiGe layer so as to make it relaxed.DCXRD,AFM,and TEM measurements indicate that the strain relaxed degree of SiGe layer is 85%,RMS roughness is 1.02nm,and threading dislocation density is at most 1e7cm－2.At room temperature,a maximum hole mobility of strained-Si pMOSFET is 140cm2/（V·s）.Device performance is comparable to that of devices achieved on several microns thick relaxed virtual SiGe substrates.