In situ X-ray diffraction study on epitaxial growth of Si_xGe_1−x on Si by aluminium-assisted crystallization

In situ X-ray diffraction study is applied to investigate the role of annealing time in the epitaxial growth of Si_xGe_1−x on Si by aluminium-assisted crystallization at relatively low temperatures (350–450 °C). The evolution of the Si_xGe_1−x film with annealing time can be divided into two stages: (i) Si_xGe_1−x epitaxial growth on Si through Ge/Al layer exchange and (ii) Si_xGe_1-x diffusion into Si substrate. The speed of layer exchange increases with elevating temperature. After the completion of layer exchange, the Si_xGe_1−x starts diffusing into the Si substrate with prolonged annealing time. The Si content of the epitaxial Si_xGe_1−x film keeps increasing with time throughout the annealing. This increase is rapid during Ge/Al layer exchange but is gradual during Si_xGe_1−x diffusion into Si substrate.