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US 2012/0042947 A1Published application
Methods and apparatus for manufacturing monocrystalline cast silicon and monocrystalline cast silicon bodies for photovoltaics
OwnerNathan G. Stoddardinventor
Life of this patent
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Abstract
Methods and apparatuses are provided for casting silicon for photovoltaic cells and other applications. With such methods and apparatuses, a cast body of monocrystalline silicon may be formed that is free of, or substantially free of, radially-distributed impurities and defects and having at least two dimensions that are each at least about 35 cm is provided.
Claims33
A method of manufacturing cast silicon
- A method of manufacturing a solar cell, comprising:
- providing a body of cast silicon formed by:
- placing molten silicon in contact with at least one silicon seed crystal in a vessel having one or more side walls heated to at least the melting temperature of silicon and at least one wall for cooling;
- and
- forming a solid body comprising monocrystalline silicon, having at least two dimensions each being at least about 10 cm, by cooling the molten silicon to control crystallization, wherein the forming includes forming a solid-liquid interface at an edge of the molten silicon that at least initially parallels the at least one wall for cooling, the interface being controlled during the cooling so as to move in a direction that increases a distance between the molten silicon and the at least one wall for cooling;
- forming at least one wafer from the body;
- forming at least one p-n junction;
- and
- forming electrically conductive contacts on the wafer.
6 more elements
A method of manufacturing a solar cell, comprising:
- providing a body of cast silicon formed by:
- placing a geometric arrangement of a plurality of silicon seed crystals comprising monocrystalline silicon on at least one surface in a crucible having one or more side walls heated to at least the melting temperature of silicon and at least one wall for cooling, wherein the geometric arrangement includes close-packed polygons;
- placing molten silicon in contact with the geometric arrangement of the silicon seed crystals;
- and forming a solid body comprising monocrystalline silicon, having at least two dimensions each being at least about 10 cm, by cooling the molten silicon to control crystallization, wherein the forming includes forming a solid-liquid interface at an edge of the molten silicon that parallels the at least one wall for cooling, the interface being controlled during the cooling so as to move in a direction that increases a distance between the molten silicon and the at least one wall for cooling;
- forming at least one wafer from the body;
- forming at least one p-n junction;
- and
- forming electrically conductive contacts on the wafer.
5 more elements
A method of manufacturing a solar cell, comprising:
- providing a body of cast silicon formed by:
- arranging a plurality of silicon seed crystals comprising monocrystalline silicon in a predetermined pattern on at least two surfaces of a crucible;
- placing molten silicon in contact with the monocrystalline silicon seed crystals;
- and
- forming a solid body comprising monocrystalline silicon, having at least two dimensions each being at least about 10 cm, by cooling the molten silicon from the at least two surfaces of the crucible to control crystallization, wherein the forming includes controlling a solid-liquid interface at an edge of the molten silicon during the cooling so as to move in a direction that increases a distance between the molten silicon and the at least two surfaces of the crucible
- forming at least one wafer from the body;
- forming at least one p-n junction;
- and
- forming electrically conductive contacts on the wafer.
6 more elements
A method of manufacturing a solar cell, comprising:
- providing a body of cast silicon formed by;
- placing silicon feedstock in contact with at least one silicon seed crystal comprising monocrystalline silicon on at least one surface;
- heating the silicon feedstock and the at least one silicon seed crystal to the melting temperature of silicon;
- controlling the heating so that the at least one silicon seed crystal does not melt completely, the controlling comprising maintaining a ΔT of about 0.1° C./min or less, as measured on an outside surface of the crucible, after reaching the melting temperature of silicon elsewhere in the crucible;
- and
- forming a solid body comprising monocrystalline silicon by cooling the silicon;
- forming at least one wafer from the body;
- forming at least one p-n junction;
- and
- forming electrically conductive contacts on the wafer.
7 more elements
A method of manufacturing a solar cell, comprising:
- providing a body of cast silicon formed by:
- placing a geometric arrangement of a plurality of silicon seed crystals comprising monocrystalline silicon on at least one surface in a crucible, wherein the geometric arrangement includes close-packed polygons;
- placing silicon feedstock in contact with the plurality of silicon seed crystals on the at least one surface;
- heating the silicon feedstock and the plurality of silicon seed crystals to the melting temperature of silicon;
- controlling the heating so that the plurality of seed crystals does not melt completely, the controlling comprising maintaining a ΔT of about 0.1° C./min or less, as measured on an outside surface of the crucible, after reaching the melting temperature of silicon elsewhere in the crucible;
- and
- forming a solid body comprising monocrystalline silicon by cooling the silicon;
- forming at least one wafer from the body;
- forming at least one p-n junction;
- and
- forming electrically conductive contacts on the wafer.
8 more elements
A method of manufacturing a solar cell, comprising:
- providing a body of cast silicon formed by:
- arranging a plurality of silicon seed crystals comprising monocrystalline silicon in a predetermined pattern on at least two surfaces of a crucible;
- placing silicon feedstock in contact with the plurality of silicon seed crystals on the at least two surfaces;
- heating the silicon feedstock and the plurality of silicon seed crystals to the melting temperature of silicon;
- controlling the heating so that the plurality of silicon seed crystals does not melt completely, the controlling comprising maintaining a ΔT of about 0.1° C./min or less, as measured on an outside surface of the crucible, after reaching the melting temperature of silicon elsewhere in the crucible;
- and,
- once at least one monocrystalline silicon seed crystal is partially melted, forming a solid body comprising monocrystalline silicon by cooling the silicon.
- forming at least one wafer from the body;
- forming at least one p-n junction;
- and
- forming electrically conductive contacts on the wafer.
8 more elements
A method of manufacturing a solar cell, comprising:
- providing a body of cast silicon formed by:
- placing molten silicon in contact with at least one silicon seed crystal in a vessel having one or more side walls heated to at least the melting temperature of silicon, the at least one silicon seed crystal arranged to cover an entire or substantially an entire area of a surface of the vessel;
- and
- forming a solid body comprising monocrystalline silicon, optionally having at least two dimensions each being at least about 10 cm, by cooling the molten silicon to control crystallization;
- forming at least one wafer from the body;
- forming at least one p-n junction;
- and
- forming electrically conductive contacts on the wafer.
5 more elements
A body of continuous monocrystalline silicon being free or substantially free of radially-distributed impurities and defects, and having at least two dimensions that are each at least about 25 cm and a third dimension at least about 20 cm.
A body of continuous monocrystalline silicon having a carbon concentration of about 2×1016 atoms/cm3 to about 5×1017 atoms/cm3, an oxygen concentration not exceeding 5×1017 atoms/cm3, a nitrogen concentration of at least 1×1015 atoms/cm3, and having at least two dimensions that are each at least about 25 cm and a third dimension at least about 20 cm.
A body of continuous cast monocrystalline silicon having at least two dimensions that are each at least about 35 cm.
A solar cell, comprising:
- a wafer formed from a body of continuous monocrystalline silicon being free or substantially free of radially-distributed impurities and defects, the body having at least two dimensions that are each at least about 25 cm and a third dimension at least about 20 cm;
- a p-n junction in the wafer;
- an anti-reflective coating on a surface of the wafer;
- at least one layer selected from a back surface field and a passivating layer;
- and
- electrically conductive contacts on the wafer.
3 more elements
A solar cell, comprising:
- a wafer formed from a body of continuous cast monocrystalline silicon, the body having at least two dimensions that are each at least about 35 cm;
- a p-n junction in the wafer;
- an anti-reflective coating on a portion of a surface of the wafer;
- at least one layer selected from a back surface field and a passivating layer;
- and
- electrically conductive contacts on the wafer.
3 more elements
A solar cell, comprising:
- a continuous monocrystalline silicon wafer formed from a body of continuous cast monocrystalline silicon, the wafer having at least one dimension that is at least about 50 mm, and the body having at least two dimensions that are each at least about 25 cm and a third dimension at least about 20 cm;
- a p-n junction in the wafer;
- an anti-reflective coating on a portion of a surface of the wafer;
- at least one layer selected from a back surface field and a passivating layer;
- and electrically conductive contacts on the wafer.
2 more elements
A wafer, comprising:
- silicon formed from a body of continuous monocrystalline silicon being free or substantially free of radially-distributed impurities and defects, the body having at least two dimensions that are each at least about 25 cm and a third dimension at least about 20 cm.
A wafer, comprising:
- silicon formed from a body of continuous cast monocrystalline silicon, the wafer having at least one dimension that is at least about 50 mm, and the body having at least two dimensions that are each at least about 25 cm and a third dimension at least about 20 cm.
A body of near-monocrystalline silicon being free or substantially free of radially-distributed impurities and defects, and having at least two dimensions that are each at least about 25 cm and a third dimension at least about 20 cm.
A body of near-monocrystalline silicon having a carbon concentration of about 2×1016 atoms/cm3 to about 5×1017 atoms/cm3, an oxygen concentration not exceeding 5×1017 atoms/cm3, a nitrogen concentration of at least 1×1015 atoms/cm3, and having at least two dimensions that are each at least about 25 cm and a third dimension at least about 20 cm.
A body of continuous cast near-monocrystalline silicon having at least two dimensions that are each at least about 35 cm.
A solar cell, comprising:
- a wafer formed from a body of near-monocrystalline silicon being free or substantially free of radially-distributed impurities and defects, the body having at least two dimensions that are each at least about 25 cm and a third dimension at least about 20 cm;
- a p-n junction in the wafer;
- an anti-reflective coating on a surface of the wafer;
- at least one layer selected from a back surface field and a passivating layer;
- and
- electrically conductive contacts on the wafer.
3 more elements
A solar cell, comprising:
- a wafer formed from a body of cast near-monocrystalline silicon, the body having at least two dimensions that are each at least about 35 cm;
- a p-n junction in the wafer;
- an anti-reflective coating on a surface of the wafer;
- at least one layer selected from a back surface field and a passivating layer;
- and
- electrically conductive contacts on the wafer.
3 more elements
A wafer, comprising:
- silicon formed from a body of near-monocrystalline silicon being free or substantially free of radially-distributed impurities and defects, the body having at least two dimensions that are each at least about 25 cm and a third dimension at least about 20 cm.
A wafer, comprising:
- silicon formed from a body of cast near-monocrystalline silicon, the wafer having at least one dimension that is at least about 50 mm, and the body having at least two dimensions that are each at least about 25 cm and a third dimension at least about 20 cm.
Dependencies are inferred from the claim text.