Strained-Si pMOSFETs on very thin relaxed virtua l SiGe substrates are presented.The 240nm relaxed virtual Si 0.8 Ge 0.2 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 107cm -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.
