Abstract: An improved process is disclosed for the deposition in a reactor vessel of silicon on the interior walls of the reactor vessel and for the subsequent separation of the silicon from those walls. The reactor vessel has a generally rectangular cross section and is formed of a refractory material from which the deposited silicon separates by thermal expansion shear separation during cool down of the vessel and the deposited silicon. To improve the output of the deposition system, a plurality of partitions are provided in the reactor vessel and integral with the reactor walls. These partitions act as additional deposition surfaces, increasing the number of silicon sheets deposited as well as increasing the efficiency of the chemical reaction.

Abstract: A process is disclosed for removing carbonaceous material from a surface in a high pressure oxygen plasma. A surface, such as a surface of a silicon ribbon, having a layer of carbonaceous material thereon is positioned in a high pressure plasma reaction volume. A high pressure rf plasma is generated in which the plasma includes reactive and ionic oxygen species. The reactive oxygen species are directed to and react with the layer of carbonaceous material to oxidize that material. The reaction products of the oxidation step include carbon dioxide and, possibly a non-oxidizing ash material which can easily be removed from the silicon surface.

Abstract: A process is provided for forming a self-supporting semiconductor film or ribbon. A TESS substrate is prepared from a substrate of refractory material having an expansion coefficient different from the expansion coefficient of the semiconductor material. A colloidal suspension of graphite is applied to the substrate to form a thin layer of loosely adherent graphite particles. Over this layer of graphite is deposited a layer of the semiconductor material, the deposition occurring at an elevated temperature. Upon cooling from the deposition temperature, the differential thermal expansion coefficience causes the shearing at the graphite layer and therefore provides for the easy removal of the semiconductor layer from the substrate.

Abstract: Polycrystalline silicon is produced by a high pressure plasma process. A silicon halide or halosilane is reacted with hydrogen in the presence of a high pressure plasma to deposit silicon on a heated substrate. The effluent from this reaction is collected, the silicon-bearing compounds separated out, and re-introduced to the deposition reaction. The initial silicon bearing compound can be inexpensive silicon tetrachloride. Maximum utilization of all silicon bearing reaction products maximizes polycrystalline silicon production efficiency.

Abstract: A method is disclosed for the plasma hydrogenation of silicon tetrachloride. A high pressure plasma is utilized to effect a reaction of hydrogen and silicon tetrachloride to form trichlorosilane and other hydrogenated silicon chlorides.

Abstract: Polycrystalline silicon is deposited on the interior surface of a shaped container. The silicon is deposited by reacting hydrogen and a silicon bearing gas in the presence of a high pressure plasma. The silicon body is separated from the shaped container by utilizing thermal expansion shear stress.