NOVELTY - The power is provided to a radio frequency (RF) or microwave (MW) excitation source, to excite several amounts of silica and elemental carbon in a material mixture. A resulting material comprising silicon is formed from the material mixture, after waiting for a predetermined period of time. The power supplied to excitation source is reduced, and the resulting material is annealed to allow crystal growth. The carbon monoxide and carbon dioxide are removed from a reaction chamber (100) having the material mixture, while forming the resulting material.    USE - Method for forming silicon-containing material used in polycrystalline silicon sheet and textured polycrystalline silicon substrate (both claimed) used as feedstock for fabrication of photovoltaic solar cell.    ADVANTAGE - The polycrystalline silicon sheets and substrates can be formed safely and effectively in variety of shapes, during the fabrication of low-cost photovoltaic solar cell. The annealing process of the resulting material is controlled to provide desired material properties of the resulting material, and the photo-conversion efficiency of the solar cell is improved. The amount of dopant provided to the reaction chamber and the pressure in the reaction chamber can be controlled efficiently.    DETAILED DESCRIPTION - The material mixture is placed in a susceptor trough (104), and the susceptor trough is placed in the chamber before providing power to the excitation source comprising RF coil (106). The resulting material is cooled in an atmosphere of inert gas such as helium/argon (112). INDEPENDENT CLAIMS are included for the following:    (1) silicon sheet production system that includes the trough mounted on the block of graphite susceptor (102), to accept material mixture. The chamber is configured to accept the trough, and a pressure control system is configured to control the pressure within the chamber. A purging system is provided to aid in evacuating the chamber. An infrared/visible shielding (108) is provided around the excitation source. The pressure control system is provided with a throttle valve (118) and several pumps (120) connected with the chamber; and    (2) textured polycrystalline silicon substrate forming method that involves providing a textured substrate holder on a surface of the trough, and forming a silicon film within the textured substrate holder by exciting the material mixture. The silicon film is removed from the textured substrate holder. The textured substrate holder is formed of graphite, boron nitride, sapphire, zirconia or alumina.    DESCRIPTION OF DRAWING(S) - The drawing shows the block diagram of the process apparatus used for formation of polycrystalline silicon sheet.    Reaction chamber (100)    Graphite susceptor (102)    Trough (104)    RF coil (106)    Infrared/visible shielding (108)    Helium/argon (112)    Throttle valve (118)    Pump (120)