Synthesis of polycrystalline silicon films on metalized ceramic substrates with laser-assisted chemical vapor deposition

Abstract
In order to deposit polycrystalline silicon for photovoltaic solar cell application, a new low-temperature synthesis route is required. Towards this end, Laser-Assisted Chemical Vapor Deposition of polycrystalline silicon films on metalized ceramic substrates is investigated. A tunable continuous wave CO₂-laser is used in a perpendicular configuration with the substrate. In this configuration, the substrate, the reactant gases, or both are heated by the CO₂-laser. Two ceramic substrate materials, alumina (Al₂O₃) and cordierite (2 MgO + 2 Al₂O₃ + 5 SiO₂), coated with tin are used. The presence of the metal layer is necessary for the formation of polycrystalline silicon grains at substrate temperatures below 700 °C. The film thickness is 10-50 µm and the growth rate 2 µm/min.