G.t. Equipment Technologies, Inc.

Vishwanath Prasad

Mohan Chandra

Kedar Prasad Gupta

Jonathan A Talbott

Ijaz H Jafri

Michael A Costantini

Philippe Leyvraz

Allison Caster

A method and apparatus, and product by process, for the production of bulk polysilicon by a chemical vapor deposition process on a removable tube section. A quartz envelope and base plate form a CVD reactor enclosure, with external radiant heaters providing process heat through the wall of the reactor, and with process gas inlet and outlet ports located in the base plate. A tube section, preferably an EFG silicon tube-section, vertically emplaced on the base plate and capped to close the top is used as the reaction chamber. During the CVD process, deposition occurs on the inside surface of the chamber tube, the inner diameter of the deposit layer becoming increasingly smaller as the yield accumulates. In a two tube reactor, a smaller diameter, vertical middle tube is uniformly spaced and supported inside the chamber tube for fall flow of process gas over and under the middle tube so that deposition occurs on the three exposed tube surfaces. A co-axial core tube and heater mounted on the base plate provides yet more deposition surface area, improved thermal gradient in the reaction chamber, and greater thermal efficiency to the process. The full, double sided deposit on the middle tube and exterior deposit on the core tube are unique products of the process.

Cold wall reactor and method for chemical vapor deposition of bulk polysilicon

A method and apparatus, and product by process, for the production of bulk polysilicon by broad area chemical vapor deposition, consisting of a quartz envelope and base plate forming a reactor enclosure, with external radiant heaters providing the heat source. A thin wall, edge-defined film fed growth (EFG) silicon tube section is used as the deposition casing and reaction chamber wall. The tube is capped at the top and sealed to the base plate to form the reaction chamber. External heaters radiate heat through the quartz enclosure to heat the tube wall to deposition temperature. A through flow of process gas is introduced to initiate the deposition. A uniform wide surface area deposit occurs on the inside surface of the tube, causing the diameter to become increasingly smaller as the yield accumulates. In a two tube reactor, a smaller core tube is uniformly spaced and supported inside the outer tube for full flow of process gas around the core tube so that deposition occurs on both the outside and inside surface of the core tube. The outer tube may be configured for preheating by a flow of electrical current from the base plate to the cover plate.

Method and apparatus for chemical vapor deposition of polysilicon

A slurry recycle process for use in free-abrasive machining operations such as for wire saws used in wafer slicing of ingots, where the used slurry is separated into kerf-rich and abrasive-rich components, and the abrasive-rich component is reconstituted into a makeup slurry. During the process, the average particle size of the makeup slurry is controlled by monitoring the condition of the kerf and abrasive components and making necessary adjustments to the separating force and dwell time of the separator apparatus. Related pre-separator and post separator treatments, and feedback of one or the other separator slurry output components for mixing with incoming used slurry and recirculation through the separator, provide further effectiveness and additional control points in the process. The kerf-rich component is eventually or continually removed; the abrasive-rich component is reconstituted into a makeup slurry with a controlled, average particle size such that the products of the free-abrasive machining method using the recycled slurry process of the invention are of consistent high quality with less TTV deviation from cycle to cycle for a prolonged period or series of machining operations.

Method and apparatus for improved wire saw slurry

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East Setauket, NY, United States of America

Vishwanath Prasad