Abstract: Methods for producing silicon tetrafluoride by acid digestion of fluoride salts of alkali metal or alkaline earth metal and aluminum, optionally, in the presence of a source of silicon; methods for producing silane that include acid digestion of by-products of silane production to produce silicon tetrafluoride.

Abstract: The present disclosure generally relates to methods for recovering silicon from saw kerf, or an exhausted abrasive slurry, resulting from the cutting of a silicon ingot, such as a single crystal or polycrystalline silicon ingot. More particularly, the present disclosure relates to methods for isolating and purifying silicon from saw kerf or the exhausted slurry, such that the resulting silicon may be used as a raw material, such as a solar grade silicon raw material.

Abstract: Processes and systems for purifying silane-containing streams are disclosed with relatively less silane being lost in impurity streams by use of distillation and/or condensation operations.

Abstract: Methods for producing multicrystalline silicon ingots by use of a Czochralski-type crystal puller and pulling assemblies that include a plurality of seed crystals for pulling multicrystalline silicon ingots.

Abstract: Processes and systems for purifying silane-containing streams are disclosed with relatively less silane being lost in impurity streams by use of distillation and/or condensation operations.

Abstract: Processes and systems for purifying silane-containing streams are disclosed with relatively less silane being lost in impurity streams by use of distillation and/or condensation operations.

Abstract: Methods for producing crucibles for holding molten material that contain a reduced amount of gas pockets are disclosed. The methods may involve use of molten silica that may be outgassed prior to or during formation of the crucible. Crucibles produced from such methods and ingots and wafers that are produced from crucibles with a reduced amount of gas pockets are also disclosed.

Abstract: Shell and tube heat exchangers that include a baffle arrangement that improves the temperature profile and flow pattern throughout the exchanger and/or that are integral with a reaction vessel are disclosed. Methods for using the exchangers including methods that involve use of the exchanger and a reaction vessel to produce a reaction product gas containing trichlorosilane are also disclosed.

Abstract: A system for ultrasonically cleaning one or more wires of a wire saw for slicing semiconductor or solar material into wafers. The system includes an ultrasonic transducer connected to a sonotrode. The system also includes a sonotrode plate adjacent to one or more of the wires. The sonotrode plate has an opening that exposes the sonotrode to one or more of the wires. The system further includes a tank for delivering a flow of liquid to contact the sonotrode and one or more of the wires. The tank is positioned on the same side of the wires as the sonotrode plate. The ultrasonic transducer is configured to vibrate and form cavitations in the liquid for the removal of contaminants from a surface of one or more of the wires.

Abstract: The present disclosure generally relates to methods for recovering silicon from saw kerf, or an exhausted abrasive slurry, resulting from the cutting of a silicon ingot, such as a single crystal or polycrystalline silicon ingot. More particularly, the present disclosure relates to methods for isolating and purifying silicon from saw kerf or the exhausted slurry, such that the resulting silicon may be used as a raw material, such as a solar grade silicon raw material.

Abstract: A method of preparing a silicon melt in a crucible for use in the manufacture of cast silicon, wherein the crucible comprises an opening, an opposing bottom surface, and at least one sidewall joining the opening and the bottom surface. The method comprises charging a silicon spacer to the bottom surface of the crucible; arranging a monocrystalline silicon seed crystal on the silicon spacer such that no surface of the monocrystalline silicon material is in contact with the bottom surface of the crucible; charging polycrystalline silicon feedstock to the crucible; and applying heat through at least one of the opening and the at least one sidewall in order to form a partially melted charge of silicon in the crucible.

Abstract: A cast silicon crystalline ingot comprises two major generally parallel surfaces, one of which is the front surface and the other of which is the back surface; a perimeter surface connecting the front surface and the back surface; and a bulk region between the front surface and the back surface; wherein the cast silicon crystalline ingot has no transverse dimension less than about five centimeters; the cast silicon crystalline ingot has a dislocation density of less than 1000 dislocations/cm2. Wafers sliced from the cast silicon crystalline ingot have solar cell efficiency of at least 17.5% and light induced degradation no greater than 0.2%.

Abstract: A process is provided for evaluating oxygen precipitates in a single crystal silicon sample. The process comprises (a) annealing the single crystal silicon sample at a temperature sufficient to selectively grow as-grown oxygen precipitates having a size of about 25 nm or more and selectively dissolve as-grown oxygen precipitates having a size of about 25 nm or less; (b) cooling the single crystal silicon sample at a cooling rate sufficient to inhibit the nucleation of oxygen precipitates having a size of about 25 nm or less; (c) coating a surface of the single crystal silicon sample with a composition containing a metal capable of decorating oxygen precipitates; and (d) annealing the coated single crystal silicon sample at a temperature, for a duration, and in an atmosphere sufficient to decorate the oxygen precipitates in the single crystal silicon sample.

Abstract: A heat exchanger for vaporizing a liquid and a method of using the same are disclosed. The heat exchanger includes a housing, a tube, a heater, and a plurality of non-reactive members. The tube is disposed in the interior of the housing and has an inlet and an outlet. The heater is configured to heat the tube. The plurality of non-reactive members are disposed in an interior cavity of the tube in an arrangement such that a plurality of voids are defined between the members and the tube. The arrangement also permits liquid to pass through the voids and travel from the inlet of the tube to the outlet of tube. The plurality of non-reactive members and the tube transfer heat to the liquid as the liquid passes through the plurality of voids in order to vaporize the liquid.

Abstract: Processes and systems for purifying silane-containing streams and, in particular, for purifying silane-containing streams that also contain ethylene are disclosed. The processes and systems may be arranged such that one or more ethylene reactors are downstream of light-end distillation operations.

Abstract: Methods are disclosed for determining mounting locations of ingots on a wire saw machine. The methods include measuring a test surface of a test wafer previously sliced by the wire saw machine from a test ingot to calibrate the system. A magnitude and a direction of an irregularity of the measured test surface of the test wafer is then determined. The mounting location is then determined for another ingot to be mounted on the ingot holder based on at least one of the magnitude and direction of the irregularity of the measured test surface of the test wafer.

Abstract: Systems and methods are disclosed for controlling the surface profiles of wafers cut in a wire saw machine. The systems and methods described herein are generally operable to alter the nanotopology of wafers sliced from an ingot by controlling the shape of the wafers. The shape of the wafers is altered by changing the temperature and/or flow rate of a temperature-controlling fluid that comes in contact with the ingot. Different feedback systems can be used to determine the temperature of the fluid necessary to generate wafers having the desired shape and/or nanotopology.

Abstract: Methods and systems for use in detecting an air pocket in a single crystal material are described. One example method includes providing a matrix including a plurality of data units, the plurality of data units including image data related to a region of interest of the single crystal material; defining a first half and a second half of the matrix based on a first axis passing through the center of the matrix; determining, by a processor, a difference between each data unit of the first half and a corresponding data unit of the second half; calculating, by the processor, a first index value based on the determined differences; and identifying an air pocket within the single crystal material based on the first index value and a predetermined threshold.

Abstract: Methods and systems for use in detecting an air pocket in a single crystal material are described. One example method includes providing a matrix including a plurality of data units, the plurality of data units including image data related to a region of interest of the single crystal material; determining, by a processor, a difference between data units of the matrix and a corresponding data unit of the matrix, wherein the corresponding data unit is defined by a first operation of the matrix; calculating, by the processor, a first index value based on the differences of the corresponding data units; and identifying an air pocket within the single crystal material based on the first index value and a predetermined threshold.

Abstract: Methods for producing silicon on insulator structures with a reduced metal content in the device layer thereof are disclosed. Silicon on insulator structures with a reduced metal content are also disclosed.