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US 12,162,761 B2Granted
Silicon granules for the preparation of trichlorosilane and associated production method
AssigneeRosi
InventorDaniel Bajolet
Life of this patent
Estimating the term…
Abstract
A silicon granule, in particular, for the preparation of trichlorosilane, having a size of between 10 and 500 microns, and comprising: dopants in a weight fraction of less than 5 ppm; at least one co-catalyst selected from copper, iron, aluminum and calcium, in a weight fraction of between 1 and 2500 ppm; and metallic impurities, with exclusion of the at least one co-catalyst, in a weight fraction of less than 50 ppm.
Claims9
A method for the production of silicon granules, comprising:
- a) a step of supplying silicon waste from the cutting of photovoltaic quality ingots by diamond wire, the waste comprising silicon particles covered with an oxide layer and mixed with impurities in an aqueous medium;
- b) a step of chemical treatment of the waste to separate the silicon particles from all or part of the impurities, and to dry the silicon particles to form a powder;
- c) a metallurgical treatment step of the powder to melt the silicon particles and form a liquid silicon bath;
- d) a step of introducing co-catalysts consisting of iron, aluminum, and calcium into the liquid silicon bath, in an amount such that a total mass fraction of the co-catalysts in the granules is between 160 and 2300 ppm;
- and
- e) a step of solidifying the liquid silicon to form the silicon granules by rapid cooling to ensure a uniform concentration of the co-catalysts as intermetallic compounds in the silicon granules, the silicon granules having a size between 10 and 500 microns, and comprising:
- dopants, including phosphorus or boron, in a mass fraction of less than 5 ppm;
- the co-catalysts with a total mass fraction between 160 and 2300 ppm;
- and
- metallic impurities, excluding the co-catalysts, in a mass fraction of less than 50 ppm, wherein the method further comprises:
- mixing crushed substrates with the silicon waste from the cutting of photovoltaic quality ingots by diamond wire in step a);
- or
- melting crushed substrates with the silicon powder in step c);
- or both.
11 more elements
A method for the production of silicon granules, comprising:
- supplying silicon waste from the cutting of photovoltaic quality ingots by diamond wire, the silicon waste comprising silicon particles and impurities in an aqueous medium;
- separating the silicon particles from all or part of the impurities;
- melting the silicon particles and forming a liquid silicon bath;
- introducing co-catalysts consisting of iron, aluminum, and calcium into the liquid silicon bath, in an amount such that a total mass fraction of the co-catalysts in silicon granules is between 100 and 2500 ppm;
- and
- solidifying the liquid silicon to form the silicon granules, by rapid cooling to ensure a uniform concentration of the co-catalysts as intermetallic compounds in the silicon granules, the silicon granules having a size between 10 and 500 microns, and comprising:
- dopants, including phosphorus or boron, in a mass fraction of less than 5 ppm;
- the co-catalysts with a total mass fraction between 100 and 2500 ppm;
- and
- metallic impurities, excluding the co-catalysts, in a mass fraction of less than 50 ppm.
7 more elements
Dependencies are inferred from the claim text.