Growth of strained-Si material using low-temperature Si combined with ion implantation technology

In order to fabricate strained-Si MOSFETs,we present a method to prepare strained-Si material with highquality surface and ultra-thin SiGe virtual substrate.By sandwiching a low-temperature Si（LT-Si） layer between a Si buffer and a pseudomorphic Si;Ge;layer,the surface roughness root mean square（RMS） is 1.02 nm and the defect density is 10;cm;owing to the misfit dislocations restricted to the LT-Si layer and the threading dislocations suppressed from penetrating into the Si;Ge;layer.By employing P;implantation and rapid thermal annealing, the strain relaxation degree of the Si;Ge;layer increases from 85.09%to 96.41%and relaxation is more uniform. Meanwhile,the RMS（1.1nm） varies a little and the defect density varies little.According to the results,the method of combining an LT-Si layer with ion implantation can prepare high-quality strained-Si material with a high relaxation degree and ultra-thin SiGe virtual substrate to meet the requirements of device applications.