在SiO2衬底上生长多晶Ge薄膜的结晶机制研究

The crystallization mechanisms of poly-crystalline Ge thin films grown on SiO2 substrate

在低温条件下生长的多晶Ge薄膜在光伏器件和电子器件领域具有非常广泛的应用。在实验研究中,利用Al诱导结晶的生长方法在200℃的低温条件下,在SiO2衬底上生长出结晶质量很好的多晶Ge薄膜。实验中,特意在Al薄膜和非晶Ge薄膜之间生长了一层很薄的GeOx扩散控制层。研究发现,在Al/a-Ge双层薄膜样品中,当Al薄膜与非晶Ge薄膜完成层交换后,生长出的多晶Ge薄膜的晶向得到了有效控制。在非晶Ge薄膜转变为多晶Ge薄膜的结晶过程中,通过进一步控制Ge晶颗粒的成核位置和密度以及二维生长的速率就可以制备出微米量级大小的Ge晶颗粒和(111)晶向较好的多晶Ge薄膜。

The poly-crystalline Ge thin films grown under low temperature is of great application in photovoltaic devices and electronics applications. We have formed the poly-crystalline Ge thin films grown on SiO2 substrate by Al-induced crystallization under low temperatures at 200 ℃ in our experiments. A much thinner GeOx diffusion control interfacial layer, grown between Al thin films and the underlying a-Ge thin films intentionally,is found to achieve layer exchange while the crystal orientation of poly-crystalline Ge thin films had been controlled effectively within Al/a-Ge bilayer thin films. Poly-crystalline Ge thin films with micron-size grains and preferred(111)-orientation are prepared by the controlled c-Ge grain nucleation and planar growth velocity during the crystallization of a-Ge thin films transformed to c-Ge thin films.