Patent ID: 8501139

Claim:
A method for producing a silicon (Si) and/or germanium (Ge) foil, said method comprises: dissolving Si and/or Ge source material in a molten metallic bath to form a molten solution, wherein a density of solid Si and/or Ge is lower than a density of the molten metallic bath by at least 1 g/cm 3 ; cooling at least a portion of the molten solution from a saturation temperature through an initial precipitation temperature to a lower temperature T 1 , wherein T 1 is lower than the initial precipitation temperature by at least 80° C., or wherein T 1 is lower than the saturation temperature by at least 100° C., without contacting a wafer with the molten solution, whereby Si and/or Ge precipitates out of the at least a portion of the molten solution and grows as a floating Si and/or Ge foil on a top surface of the at least a portion of the molten solution, without a substrate floating in the molten solution, at an interfacial area, wherein the interfacial area is larger than an area of a cross-section of the foil, the cross-section being taken in a plane perpendicular to the interfacial area along a width of the floating foil, and said initial precipitation temperature is the temperature at which the at least a portion of the molten solution is cooled sufficiently to initiate precipitation of the Si and/or Ge from the at least a portion of the molten solution; and separating at least a portion of the floating Si and/or Ge foil from the interfacial area when a thickness of the at least a portion of the floating foil, which thickness is measured along a direction perpendicular to the interfacial area, is in a range from about 10 micrometers to about 200 micrometers.