Influence of substrate on the growth of microcrystalline silicon thin films deposited by plasma enhanced chemical vapor deposition

Microcrystalline silicon (mu c-Si) thin films are widely used for silicon thin film solar cells, especially in the high performance tandem solar cells which comprise an amorphous silicon junction at the top and a mu c-Si junction at the bottom. One of the major factors affecting the photovoltaic properties of mu c-Si thin film solar cells of thin films is the quality of the mu c-Si thin films. In this work, we investigated the effect of substrates on the crystallization characteristics and growth behaviors of mu c-Si thin films grown by the plasma enhanced chemical vapor deposition method (PECVD), and found that substrates have a strong effect on the crystallization characteristics of mu c-Si thin films. In addition, the growth rate of mu c-Si thin films was also highly influenced by the substrates. Three types of substrates, quartz glass, single crystalline silicon and thermally oxidized single crystalline silicon, were used for growing mu c-Si thin films from SiH4/H-2 with a flow rate ratio 2:98 at different temperatures. Crystallization characteristics of these mu c-Si thin films were studied by Raman scattering and X-ray diffraction techniques. (C) 2012 Elsevier Ltd. All rights reserved.