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Assignee1366 Technologies, Inc.
InventorsRalf Jonczyk, Brian D. Kernan, G.D. Stephen Hudelson, Adam M. Lorenz, Emanuel M. Sachs
Estimating the term…
A semiconductor wafer forms on a mold containing a dopant. The dopant dopes a melt region adjacent the mold. There, dopant concentration is higher than in the melt bulk. A wafer starts solidifying. Dopant diffuses poorly in solid semiconductor. After a wafer starts solidifying, dopant can not enter the melt. Afterwards, the concentration of dopant in the melt adjacent the wafer surface is less than what was present where the wafer began to form. New wafer regions grow from a melt region whose dopant concentration lessens over time. This establishes a dopant gradient in the wafer, with higher concentration adjacent the mold. The gradient can be tailored. A gradient gives rise to a field that can function as a drift or back surface field. Solar collectors can have open grid conductors and better optical reflectors on the back surface, made possible by the intrinsic back surface field.
A semiconductor wafer for use as a solar collector, the wafer comprising a body having a first and a second surface, the body having a dopant concentration profile, there being a larger concentration of dopant at a first surface of the wafer, and a continuous transition to a lesser concentration of dopant at a second surface of the wafer, the larger concentration being at least three times the lesser concentration, wherein the first surface of the wafer and the second surface of the wafer are opposite surfaces of the wafer separated by the body.
A semiconductor wafer for use as a solar collector, the wafer comprising a body having a first and a second surface, the body having a resistivity profile, there being a smaller resistivity at a first surface of the wafer, and a continuous transition to a larger resistivity at a second surface of the wafer, the larger resistivity being at least three times the smaller resistivity, further, where any metallic impurities that are present in the body are present at the first surface to a degree less than ten times the degree of metallic impurities that are present at the second surface, wherein the first surface of the wafer and the second surface of the wafer are opposite surfaces of the wafer separated by the body.
A solar collector comprising a plurality of semiconductor wafers, each wafer comprising a body having a first and a second surface, the body having a dopant concentration profile, there being a larger concentration of dopant at a first surface of the wafer, and a continuous transition to a lesser concentration of dopant at a second surface of the wafer, the larger concentration being at least three times the lesser concentration, further, where any metallic impurities that are present in the body are present at the first surface to a degree less than ten times the degree of metallic impurities that are present at the second surface, wherein the first surface of the wafer and the second surface of the wafer are opposite surfaces of the wafer separated by the body.
Dependencies are inferred from the claim text.