Multicrystalline silicon ingots, silicon masteralloy, method for increasing the yield of multicrystalline silicon ingots for solar cells
AssigneeRec Solar Norway AS
InventorsGunnar Halvorsen, Anne-Karin Soiland
Life of this patent
Estimating the term…
Abstract
The present invention comprises directionally solidified multicrystalline silicon ingots, a silicon masteralloy for increasing the efficiency of solar cells made from wafers cut from the silicon ingots, method for increasing the yield when producing multicrystalline silicon ingots from a silicon melt by directional solidification. Further the present invention comprises a method for preparing said silicon masteralloy.
Claims7
A method for minimizing or removing the red zone in directional solidified multicrystalline silicon ingots comprising adding calcium in its elemental form, or in the form of a silicon-calcium masteralloy comprising elemental calcium in an amount of 0.5-20 weight %, the remaining being high purity silicon, to a silicon melt in an amount chosen from one of the following ranges:
- 5-9.99 ppmw, 10-500 ppmw, 500-550 ppmw prior to subjecting the silicon melt to directional solidification in a crucible.
A method for preparing a silicon-calcium masteralloy for addition to a silicon melt when making directionally solidified multicrystalline silicon ingot, wherein said silicon-calcium masteralloy comprises elemental calcium in an amount chosen from one of the following ranges:
- 0.5-20 weight %, 1-15 weight %, 5-15 weight %, the remaining being high purity silicon, the method comprising adding elemental calcium to a molten high purity silicon in an amount chosen from one of the following ranges 0.5-20 weight %, 1-15 weight %, 5-15 weight %, homogenizing a resulting alloy and solidifying the resulting alloy to provide the silicon-calcium masteralloy.
Dependencies are inferred from the claim text.