Gtat Corporation

G.t. Equipment Technologies, Inc.

Gt Solar Incorporated

Carl Chartier

Chandra P Khattak

Yuepeng Wan

Santhana Raghavan Parthasarathy

Adrian Servini

Bhuvaragasamy G Ravi

Dave Lackey

Mohan Chandra

Andriy M Andrukhiv

Jonathan A Talbott

Kedar Prasad Gupta

Parthasarathy Santhanaraghavan

Dean C Skelton

Jeffrey C Gum

Parthasarathy S Raghavan

David M Darling

Glen Alan Burgess

L Dolan Roman

Andy Schweyen

Keith Ballenger

A crystal growth furnace comprising a crucible containing at least feedstock material and a liquid-cooled heat exchanger that is vertically movable beneath the crucible to extract heat from it to promote the growth of a crystalline ingot is disclosed. The liquid-cooled heat exchanger comprises a heat extraction bulb made of high thermal conductivity material that is vertically movable into thermal communication with the crucible to extract heat from the crucible using a liquid coolant. A liquid-cooled heat exchanger enclosed in a sealed tubular outer jacket is also disclosed as is a method for producing a crystalline ingot using a vertically movable liquid-cooled heat exchanger.

Liquid-cooled heat exchanger

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 preventing molten material breach in a crystal growth apparatus includes providing a chamber of the crystal growth apparatus which is coated with a ceramic material. The chamber can be coated on an interior surface to prevent damage to the chamber itself, which is made of steel, and to prevent steam explosions in the water-cooled chamber. Ceramic blanket layers also can be provided over the coated interior surface of the chamber. As a result, it is possible to produce high quality crystalline products while minimizing the hazards and costs in the event of a spill of molten material.

Crystal growth apparatus with ceramic coating and methods for preventing molten material breach in a crystal growth apparatus

Systems and methods are provided to promote uniform thermal environment to feedstock material (e.g., silicon) in a crucible of a crystal growth apparatus are provided herein. More specifically, a heating system may be arranged in the crystal growth apparatus so as to include at least a first and second heating element which are configured to distribute heat axisymmetrically to the feedstock material and the second heating element that is configured to distribute heat symmetrically to the feedstock material to thereby provide uniform heat distribution to the feedstock material in the crucible to allow for increased consistency in crystal ingot quality.

Heater assembly for crystal growth apparatus

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

An apparatus for the automated measurement and recording of the electrical resistivity of a semiconductor boule or ingot using the method of four probes has a four point boule support grid is provided adjacent to the home position of a four tip probe which is equipped with three axis linear mobility, rotational capability, and computer control, to provide automated mapping and testing of an &ldquo;as grown&rdquo; or ground semiconductor boule with cropped ends, for obtaining and recording resistivity data.

Apparatus for automatically measuring the resistivity of semiconductor boules by using the method of four probes

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Manchester, NH, United States of America

Carl Chartier