CRYSTALLIZATION AT INITIAL-STAGE OF LOW-TEMPERATURE POLYCRYSTALLINE SILICON GROWTH USING ZNS BUFFER LAYER WITH (111) PREFERRED ORIENTATION

We developed a low-temperature growth technique for polycrystalline silicon (poly-Si). When Si is deposited on glass substrates at 450-degrees-C, it crystallizes as thickness increases, but 10-nm-thick layers of Si are mainly amorphous. Use of a ZnS buffer layer with [111] preferred orientation facilities crystallization of Si during the initial growth stages. The preferred orientation of poly-Si on glass substrates is [110], while that of poly-Si on the ZnS buffer layer is [111]. This is probably due to local epitaxial growth on polycrystalline ZnS grains with [111] preferred orientation. Raman spectroscopy showed that the ZnS buffer layer significantly improved the crystallinity of 25-nm-thick Si layers.