Influence of substrate temperature on the microstructure and optical properties of hydrogenated silicon thin film prepared with pure silane

The dependence of the optical properties and crystallization of hydrogenated silicon (Si:H) on various substrate temperatures was studied. Instead of using high-diluted silane in H2, pure silane was used as source gas. The films were grown by radiofrequency plasma-enhanced chemical vapor deposition (RF-PECVD) method at the substrate temperature ranging from 423 to 573 K. The transit between amorphous silicon (a-Si:H) and microcrystalline silicon (μc-Si:H) was characterized by atomic force microscope (AFM) morphology and X-ray diffraction (XRD) microstructure analysis. The thickness and optical constants of films were measured by spectra ellipsometer (SE) as well as scanning electron microscopy (SEM). Fourier-transform infrared spectrometer (FTIR) was used to characterize the effect of KBr substrate temperature to bonding configurations of Si:H films. Derived from Tauc relation, optical band gap Eg and coefficient B depending on the pressure during deposition process was also discussed.