Role of rapid thermal annealing in the formation of crystalline SiGe nanoparticles

In the present work, we report the formation of SiGe nanoparticles embedded in SiO2 film by atom beam sputtering method in conjunction with Rapid Thermal Annealing (RTA). Crystalline SiGe nanoparticles in the co-sputtered films are formed after rapid thermal annealing at 900 °C and 1000 °C for 1 min in N2 gas ambient. These nanoparticles were characterized using UV–vis absorption, GXRD, FTIR and Raman measurements. UV–vis spectra show blue shift of absorption edge with the increase in annealing temperature. GXRD pattern shows that particles formed are crystalline. The average size of the nanoparticle estimated from GXRD is 15 nm to 30 nm for the films annealed at temperatures 800 °C and 1000 °C respectively. FTIR spectra show the phase separation between SiGe nanoparticles and SiO2 matrix after RTA. Raman spectra show that SiGe phase is formed with c-Ge as core and c-SiGe as shell in the SiO2 matrix.