The Study of a-Ge: H Films and a-Ge: H/a-Si: H Multilayers

Improved a-Ge:H films have been produced by plasma enhanced chemical vapor deposition （PECVD） out of the gas plasma of GeH₄ and H₂. Structural, optical and electronical properties of these films have been investigated. The microcrystalline Ge film （μc-Ge:H） with ＜110＞ preferential orientation was deposited by H₂ diluted GeH₄ plasma. On the other hand, the thermal-annealing induced crystallization of as-deposited a-Ge:H films revealed ＜111＞ preferential orientation A preliminary discussion was proposed to expailan the differences between these two kinds of preferred orientation. The crytallization process and structural stability of a-Ge:H/a-Si:H multilayers have been studied by thermal-annealing. The results obtainted showed that there exists much difference of the crystallization conditions between ultra thin Ge or Si sublayers in a-Ge:H/a-Si:H multilayers and their corresponding bulk materials.