Influence of annealing atmosphere on crystallization of amorphous Si1-xGex thin film by Raman spectroscopy

In the case of a-Si thin films containing Ge atoms, the crystallization in the a-Si1-xGex (x <0.25) film was not promoted, although a-Si1-xGex (x ≥0.25) film was crystalized when the annealing in a N2 atmosphere. However, crystallization of the a-Si1-xGex (x = 0, 0.14, 0.27) were not promoted by the annealing under Ar atmosphere or in vacuum. The distortion induced by the presence of Ge atoms in the random-network of Si1-xGex, at a content below 25%, stabilizes the amorphous structure and obstructs the crystallization even in the annealing under the N2 atmosphere.