Investigation of the microstructure and optical properties of hydrogenated polymorphous silicon films prepared with pure silane

摘要

The dependences of microstructure and optical properties of hydrogenated polymorphous silicon (pm-Si:H) films on total gas pressure were studied. Instead of using high diluted silane in H-2, pure silane was used as the source gas. The films were grown by the radio-frequency plasma-enhanced chemical vapour deposition method. Fourier-transform infrared spectrometry was used to characterize the presence of SimHn clusters in pm-Si:H film deposited on KBr substrate. Atomic force microscopy (AFM) analysis characterized the morphology of the pm-Si: H films and X-ray diffraction at grazing incidence angle (XRDGI) microstructure analysis also confirmed the existence of SimHn nanocrystalline clusters in pm-Si:H. The thickness and optical constants of the films were measured by spectra ellipsometry as well as scanning electron microscopy. Derived using the Tauc relation, the dependence of optical bandgap, E-g, and coefficient, B, on the pressure during deposition process is discussed. The influence of inter-electrode distance on growth rate and surface smooth was analyzed using AFM.