Enhanced crystallinity of silicon films deposited by CVD on liquid layers (CVDOLL process): Silicon on tin layers in the presence of hydrogen chloride

Abstract

Chemical vapor deposition of silicon on a graphite substrate coated with a 5-μm-thick fluid tin layer provides a possibility for the production of large grained polycrystalline silicon layers. Using silane as a source material, crystallites can be produced with a mean grain size of about 20 μm, compared with 5 μm on a substrate without fluid layer. The grain size can be further enhanced by adding HCl as an etching agent to the gas phase. Mean crystallite sizes of 100 μm and larger can be obtained by the use of a fluid layer and a proper combination of SiH4 and HCl.