Crystal orientation was studied for films of microcrystalline SiGe alloys (μc-SixGe1-x) prepared at low substrate temperatures by RF sputtering of Ge target in SiH4 gas diluted with H2. The composition x of SixGe1-x alloy was controlled either by changing the substrate temperature Ts or the flow rates [SiH4/(SiH4+H2)]. It was found from X-ray diffraction measurements that the (220) orientation increased remarkably at substrate temperatures above 300-350°C. The maximum ratio of (220) peak height to (111) peak height increased to nearly 90 at the substrate temperature of 420°C. The (220) orientation was most notable when the composition was nearly 0.5.
