G.t. Equipment Technologies, Inc.

Gtat Corporation

Gt Solar Incorporated

Yuepeng Wan

Mohan Chandra

Carl Chartier

Santhana Raghavan Parthasarathy

Chandra P Khattak

Jonathan A Talbott

Alleppey V Hariharan

Adrian Servini

Kedar Prasad Gupta

Michael A Costantini

A method and process for the production of bulk polysilicon by chemical vapor deposition (CVD) where conventional silicon 'slim rods' commonly used in Siemens-type reactors are replaced with shaped silicon filaments of similar electrical properties but larger surface areas, such as silicon tubes, ribbons, and other shaped cross sections. Silicon containing gases, such as chlorosilane or silane, are decomposed and form a silicon deposit on the hot surfaces of the filaments The larger starting surface areas of these filaments ensures a higher production rate without changing the reactor size, and without increasing the number and length of the filaments. Existing reactors need only the adaptation or replacement of filament supports to use the new filaments. The filaments are grown from silicon melt by Edge-defined, Film-fed Growth (EFG) method. This also enables the doping of the filaments and simplification of power supplies for new reactors.

Increased polysilicon deposition in a CVD reactor

A method for making a large surface area silicon filament for production of bulk polysilicon by chemical vapor deposition (CVD) includes melting silicon and growing the filament from the melted silicon by an EFG method using a shaping die. The cross sectional shape of the silicon filament is constant over its axial length to within a tolerance of 10%. In embodiments, a plurality of identical and/or dissimilar filaments are grown simultaneously using a plurality of shaping dies. The filaments can be tubular. Filament cross sections can be annular and/or can include outwardly extending fins, with wall and/or fin thicknesses constant to within 10%. Filaments can be doped with at least one element from groups 3 and 5 of the Periodic Table. The filament can have a length equal to a length of a specified slim rod filament, and a total impedance not greater than the slim rod impedance.

Method of making large surface area filaments for the production of polysilicon in a CVD reactor

A process for making silicon ingots using a multi-part, reusable, graphite crucible of at least two mold pieces configured for assembly into an open top mold having an interior surface functional as a mold cavity for receiving molten silicon; removing or reducing a prior applied release coating from the interior surface until a uniformly smooth finish is achieved; coating the interior surface with a first layer of release coating comprising silicon nitride; coating the interior surface with a second layer of release coat comprising silica suspended in water; coating the interior surface with a third layer of release coat comprising silicon nitride; curing the release coat on said crucible; casting a silicon ingot in the crucible; and then repeating the prior steps multiple times.

Solidification of crystalline silicon from reusable crucible molds

A method for fabricating multi-cell solar devices using thermal spray deposition techniques to spray metal powder directly on solar cells and on the backing upon which solar cells are assembled, to form collection grid lines, bus bars, electrodes and interconnections between solar cells.

Making and connecting bus bars on solar cells

A method for producing formed semiconductor articles with predefined shapes such as core tubes for CVD production of bulk polysilicon. The method is characterized by thermal spray deposition of the semiconductor material in a on a temperature controlled rotating mandrel that is shaped complementarily to the desired article shape, and by later separation of the formed semiconductor body from the mandrel by thermal contraction, melting, or chemical reduction of the mandrel size.

Method of producing shaped bodies of semiconductor materials

A thermodynamically stable, protective coating layer is applied by thermal spray technique to the inner and outer surfaces of a quartz crucible used for mono or polycrystalline silicon crystallization processing, inhibiting fusion between the silicon melt and the vitreous silica of the crucible, contamination of the silicon melt by contaminants released from the crucible by devitrification, and any chemical reaction occurring between the crucible and any supporting graphite structure. A powdered form of a suitable protective coating material compatible with high temperature plasma spray techniques, such as magnesium zirconate, barium zirconate, or stabilized zirconium oxide, is fed into a high temperature and high speed plasma jet directed at the crucible. The powder particles are softened or melted in the jet and deposited on the surfaces of the quartz crucible, and allowed to cool and harden into a protective coating.

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Nashua, NH, United States of America

Yuepeng Wan