Characterization of strained silicon on relaxed SiGe layer made by H ion implantation and annealing in ultra-high vacuum ambient

Twenty-nanometer-thick Si cap layer/74-nm-thick Si0.72Ge0.28 epilayer/Si heterostructural sample was implanted by 25 keV H+ ion to a dose of 1 × 1016 cm−2 and subsequently annealed in ultra-high vacuum ambient at the temperature of 800 °C for 30 min. Rutherford backscattering/ion channeling (RBS/C), Raman spectra, high resolution X-ray diffraction (HRXRD) and atomic force microscopy (AFM) were used to characterize the structural characteristic of Si/SiGe/Si heterostructure. Investigations by RBS/C demonstrate that the Si0.72Ge0.28 layer show good crystal quality (21.1% of channel minimum yield). The relaxation degree of partially relaxed Si0.72Ge0.28 layer was around 74%, which was obtained by HRXRD. The computation process of the relaxation degree of strain in SiGe layer according to HRXRD rocking curve was also thoroughly introduced. Raman analysis revealed that stress, σ and strain, ε in the thin strained-Si layer were around 1.2 Gpa and 0.52%, respectively. In addition, the small surface roughness in the formed strained-Si/relaxed Si0.72Ge0.28 layer/Si heterostructural sample was observed via AFM image.