Decomposition and modulated structure formation during amorphous Si 1 − xGe x crystallization

Abstract

The crystallization process in undoped amorphous Si 1 − x Ge x films with x = 0.09–0.54 and those deposited on silicon oxide by molecular beam processing, was studied by X-ray diffraction and transmission electron microscopy. Amorphous SiGe decomposed via a Ge-rich phase precipitation during the crystallization at 600–850 °C for periods from 10 s to 12 h. The degree of decomposition increased with temperature. In addition, a new modulated SiGe structure, stapled perpendicular to 〈110〉 was observed. This modulated structure of SiGe was found to be stable during high-temperature annealings.