Fabrication of high-Ge fraction relaxed SiGe-On-Insulator virtual substrate by MBE growth and thermal annealing

SiGe-On-Insulator (SGOI) is a promising structure that allows the fabrication of high speed, low power consumption sub-100 nm complementary-metal-oxide-semiconductor (CMOS). Much research has been previously made on SGOI virtual substrates with the Ge concentration of 10%/spl sim/30%, which is used for strained-Si channel metal-oxide-semiconductor field-effect-transistors (MOSFETs). However, no reports have been ever made on strained-Ge channel structures grown on SGOI virtual substrates, though strained-Ge channel devices demonstrate very high mobilities, which indicates that the combination of these structures with the SGOI technology is promising. In order to grow strained-Ge channels on SGOI virtual substrates, a high Ge fraction of 60% 70% is necessary. We report on the first attempt of the fabrication of high-Ge fraction relaxed SGOI virtual substrate by MBE growth and thermal diffusion. We have achieved a single crystal high-Ge fraction (/spl sim/64%) layer, a smooth surface (/spl sim/0.4 nm rms), complete strain relaxation, and an almost uniform Ge distribution.