Effect of the substrate on the structural properties of low temperature microcrystalline silicon films - a Raman spectroscopy and atomic force microscopy investigation

Raman spectroscopy and atomic force microscopy (AFM) techniques were used to determine the properties of microcrystalline silicon (mu c-Si:H) films deposited at low temperature (100 degrees C) by a conventional plasma enhanced chemical vapor deposition (PECVD), 13.56 MHz RF, reactor from PH3/SiH4/H-2 gas mixtures in a triode coupling configuration. In this work, the correlation between surface morphology and crystallinity was investigated for mu c-Si:H films deposited on single crystal silicon, polyethylene teraphtalate (PET) and Coming 7059 glass substrates. The growth process of mu c-Si:H was investigated as a function of the deposition time in the range of 15-260 min. We observed from atomic force microscopy analysis and Raman spectroscopy that the growing surface roughness affects the crystallization process and determines the average grain size of the deposited material. We also observed that the substrate properties affected the orientation of the initial layers, acting as a seed for the formation of a crystalline-like material. (C) 2000 Elsevier Science B.V. All rights reserved.