Growth of poly-crystalline silicon–germanium on silicon by aluminum-induced crystallization

The formation of poly-crystalline silicon–germanium films on single-crystalline silicon substrates by the method of aluminum-induced crystallization was investigated. The aluminum and germanium films were evaporated onto the single-crystalline silicon substrate to form an amorphous-germanium/aluminum/single-crystalline silicon structure that was annealed at 450 °C–550 °C for 0–3 h. The structural properties of the films were examined using x-ray diffraction, Raman spectroscopy and Auger electron spectroscopy. The x-ray diffraction patterns confirmed that the initial transition from an amorphous to a poly-crystalline structure occurs after 20 min of aluminum-induced crystallization annealing process at 450 °C. The micro-Raman spectral analysis showed that the aluminum-induced crystallization process yields a better poly-crystalline SiGe film when the film is annealed at 450 °C for 40 min. The growth mechanism of the poly-crystalline silicon–germanium by aluminum-induced crystallization was also studied and is discussed.

► Aluminum-induced poly-SiGe growth on Si substrates has been studied.
► Initial transition from a-SiGe to poly-SiGe occurs after 20-min AIC at 450 °C.
► Free Ge and Si atoms undergo inter-diffusion during AIC.