Abstract: A method of surface treatment for silicon material. The method includes providing a first silicon material having a surface region. The first silicon material has a first purity characteristics and a first surface roughness characteristics. A chemical polishing process is perform to the surface region to cause the surface region to have a second roughness characteristics. Thereafter, a chemical leaching process is performed to the surface region to cause the first silicon material in a depth within a vicinity of the surface region to have a second purity characteristics. A polysilicon material characterized by a grain size greater than about 0.1 mm is formed using a deposition process overlying the surface region.

Abstract: A method for forming a photovoltaic cell. The method includes providing a first silicon material characterized by a resistivity less than about 0.5 ohm cm?1 and a first conductive type impurity characteristic. The first silicon material forms a first conductor layer for a photovoltaic cell. The method deposits a polysilicon film material overlying the surface region. In a specific embodiment, the polysilicon material has the first conductive type impurity characteristics and a resistivity greater than about 0.5 ohm cm?1. In a specific embodiment, the first polysilicon film material is characterized by a grain size greater than about 0.1 mm. The method forms a second conductive type impurity region having a second conductive type impurity characteristics opposite to the first conductive type impurity characteristics in a vicinity of a first surface region of the polysilicon film material. A second conductor layer overlies the second conductive type impurity region to form a photovoltaic cell.

Abstract: A method for forming polysilicon material for photovoltaic cells. A first silicon material characterized by a first purity level is provided. The first silicon material is subjected to a thermal process to transform the first silicon material to a molten state confined in a first spatial volume. The molten first silicon material is subjected to a directional cooling process provided in a second spatial volume for a predetermined period, removing thermal energy from a first region. A polycrystalline silicon material characterized by a second purity level and an average grain size greater than about 0.1 mm is formed from the molten first silicon material in a vicinity of the first region. One or more silicon wafers is formed from the polycrystalline silicon material. A polysilicon film material characterized by a grain size greater than about 0.1 mm is deposited overlying each of the silicon wafers.