Gtat IP Holding LLC.

Cisco Technology, Inc.

Exxon Research and Engineering Company

Memc Electronic Materials, Inc.

John P Deluca

William L Luter

Bayard K Johnson

Lawrence L Murrell

Dane C Grenoble

Dick S Williams

Neil Middendorf

Frank S Delk, Ii

Nels Patrick Ostrom

James N Highfill

Neil D Middendorf

A Czochralski growth system is disclosed comprising a crucible, a silicon delivery system comprising a feeder having a delivery point overhanging the crucible and delivering a controllable amount of silicon into the crucible, and at least one doping mechanism controllably delivering at least one dopant material to the feeder. The system can comprise two or more doping mechanisms each loaded with a different dopant material and can therefore be used to prepare silicon ingots having multiple dopants. The resulting ingots have substantially constant dopant concentrations along their axes. Also disclosed is a method of Czochralski growth of at least one silicon ingot comprising at least one dopant material, which is preferably a continuous Czochralski method.

Silicon ingot having uniform multiple dopants and method and apparatus for producing same

Efficiency of silicon photovoltaic solar cells is increased by an annealing process for immobilizing oxygen formed in Czochralski-grown silicon. The annealing process includes a short anneal in a rapid thermal annealing chamber at a high temperature, for example, greater than 1150&#xb0; C. in an oxygen-containing ambient. More preferably, the wafer is rapidly cooled to less than 950&#xb0; C. without an intermediate temperature hold, at which temperature oxygen does not nucleate and/or precipitate. Subsequent processing to form a photovoltaic structure is typically performed at relatively low temperatures of less than 1000&#xb0; C. or even 875&#xb0; C.

Thermal treatment of silicon wafers useful for photovoltaic applications

A doped silicon single crystal having a resistivity variation along a longitudinal and/or radial axis of less than 10% and a method of preparing one or a sequential series of doped silicon crystals is disclosed. The method includes providing a melt material comprising silicon into a continuous Czochralski crystal growth apparatus, delivering a dopant, such as gallium, indium, or aluminum, to the melt material, providing a seed crystal into the melt material when the melt material is in molten form, and growing a doped silicon single crystal by withdrawing the seed crystal from the melt material. Additional melt material is provided to the apparatus during the growing step. A doping model for calculating the amount of dopant to be delivered into the melt material during one or more doping events, methods for delivering the dopant, and vessels and containers used to deliver the dopant are also disclosed.

Silicon single crystal doped with gallium, indium, or aluminum

A closed loop process for producing electronic grade polycrystalline silicon from silane and fume silica from silicon tetrachloride comprises the steps of:

Closed loop process for producing polycrystalline silicon and fumed

The preparation of an ultra-stable, high surface area alpha-alumina catalyst and catalyst support suitable for use in high temperature processes such as petroleum refining processes, e.g., resid cat cracking and steam reforming, is disclosed. The process comprises impregnating high surface area gamma-alumina having narrow pores with a carbonaceous material that readily chars to form carbon. The impregnated alumina is then heated to a temperature sufficient to induce charring, following which the gamma-alumina is converted to alpha-alumina by further heating. The carbon is subsequently removed by oxidation. The alpha-alumina thus produced can withstand temperatures up to at least about 1000.degree. C. in the presence of steam without substantial loss of surface area.

Process for preparing ultra-stable, high surface area alpha-alumina

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Chesterfield, MO, United States of America

John P Deluca