Abstract: 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.

Abstract: 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° C. in an oxygen-containing ambient. More preferably, the wafer is rapidly cooled to less than 950° 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° C. or even 875° C.

Abstract: 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.

Abstract: 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.

Abstract: 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° C. in an oxygen-containing ambient, More preferably, the wafer is rapidly cooled to less than 950° 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° C. or even 875° C.

Abstract: 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.

Abstract: A audio amplifier employs microchannel plate for multiplying input electrons to produce output electrons at a rate corresponding to an audio input signal. The MCP may have a segment input source, segmented input and output electrodes or a segmented anode for allowing independent amplification of multiple input channels.

Abstract: A closed loop process for producing electronic grade polycrystalline silicon from silane and fume silica from silicon tetrachloride comprises the steps of:(a) subjecting impure silicon to hydrochlorination with hydrogen chloride to produce trichlorosilane and silicon tetrachloride together with minor amounts of dichlorosilane and monochlorosilane;(b) converting the trichlorosilane to silicon tetrachloride and silane;(c) converting the silane to polycrystalline silicon and hydrogen;(d) reacting the silicon tetrachloride from steps (a) and (b) with hydrogen and oxygen to produce fume silica and hydrogen chloride, and(e) recycling the hydrogen chloride from step (d) for use in step (a).

Abstract: Non-invasive apparatus for accelerating the process of jawbone healing and regeneration, reattachment of traumatically loosened teeth to the jawbone, or osseointegration of implants in a patient, including at least one piezoelectric transducer and connections to transmit ultrasonic frequency electrical current to the piezoelectric transducer. The ultrasonic frequency electrical current transmitted to the piezoelectric transducer causes the transducer to contract and expand volumetrically in response to a changing electrical field to generate pressure wave vibrations of ultrasonic frequency that are coupled to the bone.

Abstract: 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.

Abstract: UO.sub.2 for nuclear fuel is made from UF.sub.6. The method involves injecting UF.sub.6, with or without a nitrogen carrier, into a solution containing 1) an inert reaction medium, 2) water, 3) a Lewis base. The precipitate from the above reaction is then reduced in H.sub.2 at a temperature below 750.degree. C. to give ceramic grade UO.sub.2.

Abstract: A one-piece, integral, high strength, combined heat exchanger-reactor comprising a monolithic honeycomb structure wherein the channels thereof are divided into two or more groups; group one carrying one fluid and group two carrying another fluid which differs from the first in composition and/or temperature and/or pressure and/or direction of flow, the main design feature of the combined heat exchanger-reactor (CHER) being that group one channels extend outward parallel to the channel axis and perpendicular to the cross-section of the honeycomb and each channel of this group one being in thermal contact through common walls with channels of group two while each channel of group one is separated from other channels of group one by the intervening voids formed by the presence of the channels of group two.

Abstract: A method is disclosed for the selective separation and sequestering of plutonium from uranium which comprises contacting a gas stream containing uranium hexafluoride [at a partial pressure of 26 torr or less] and plutonium hexafluoride at any pressure with graphite whereby PuF.sub.6 is selectively intercalated into the graphite while UF.sub.6 is left unreacted in the gas stream. Preferably, the contacting of UF.sub.6 and PuF.sub.6 with graphite is conducted in the presence of excess fluorine.In another embodiment the graphite is first reacted with a chemical oxidant. Such pretreatment of the graphite renders it inert to UF.sub.6 intercalation at partial pressures over 26 torr, the pressure above which UF.sub.6 normally intercalates with graphite. Such pretreatment will have less effect on PuF.sub.6 intercalation into the prereacted graphite compound and therefore will permit the separation of UF.sub.6 -PuF.sub.

Abstract: The instant invention relates to high surface area multilayered oxide supports coated with ruthenium of the type Ru-MgO-MgAl.sub.2 O.sub.4 -MgAl.sub.2 O.sub.4 +Mg.sub.2 SiO.sub.4 -Core. The system comprises ruthenium on a critical amount of free MgO, i.e., at least 2 wt. % minimum, on pre-reacted Al.sub.2 O.sub.3 which itself is on a monolithic ceramic substrate. This combination demonstrates the desirable, and previously unachievable characteristic of resistance to ruthenium volatilization and agglomeration, coupled with high catalytic activity. The high surface area oxides (MgO+Al.sub.2 O.sub.3) are strongly bonded to and reacted with the monolithic core substructure so as to possess physical strength.