nc-Si:H薄膜的微结构特征与光学特性

Microstructural characteristics and optical properties of nc-Si:H thin films

利用射频等离子体增强型化学气相沉积(RF-PECVD)工艺,以SiH4和H2作为反应气体源,在玻璃和石英衬底上制备了氢化纳米晶硅(nc-Si:H)薄膜.采用Raman散射谱、原子力显微镜(AFM)、透射光谱方法对在不同衬底温度与不同H2稀释比条件下沉积生长薄膜的微结构和光学特性进行了实验研究.结果表明,nc-Si:H薄膜的晶粒尺寸为2.6～7.0nm和晶化率为45%～48%.在一定反应压强、衬底温度和射频功率下,随着H2稀释比的增加,薄膜的沉积速率降低,但晶化率和晶粒尺寸均有所增加,相应光学吸收系数增大.而在一定反应压强、射频功率和H2稀释比下,随着衬底温度的增加,沉积速率增加,薄膜晶化率提高.

The hydrogenated nanoerystalline silicon （nc-Si： H） films were fabricated on glass and quartz substrates by radio frequency plasma enhanced chemical vapor deposition （RF-PECVD） method, and SiH4 and H2 were used as the gas source. The microstructures and optical properties of the thin films were studied by Raman spectroscopy, atomic force microscope （AFM） and transmission spectrum at the different substrate temperatures and hydrogen dilution ratios. The results showed that the grain sizes of nc-Si： H thin films were between 2.6-7.0 nm, the crystallization rate were 45%-48%. Under a certain reactive pressure, substrate temperature and RF power, with the increasing of H2 dilution ratio, the deposition rate was reduced, the crystallization rate and grain size would increase, and the optical absorption coefficient was also increased. However, under a certain reactive pressure, RF power and H2 dilution ratio, with the increase of substrate temperature, the deposition rate would increase, and the thin film crystallization rate would increase.