Abstract: Methods and apparatus provide for contacting respective first surfaces of a plurality of donor semiconductor wafers with a glass substrate; bonding the first surfaces of the plurality of donor semiconductor wafers to the glass substrate using electrolysis; separating the plurality of donor semiconductor wafers from the glass substrate leaving respective exfoliation layers bonded to the glass substrate; and depositing a further semiconductor layer on exposed surfaces of the exfoliation layers to augment a thickness of the exfoliation layers.

Abstract: The invention is directed to a method for growing metal fluoride crystals suitable for use in below 200 nm optical lithography systems, the method comprising including at least the step of heating a crystal growth furnace to a temperature in the range of 1400-2000° C. to purify the furnace by removal of sulfur and chlorine prior to using the furnace for growing metal fluoride single crystals.

Abstract: The invention is directed to a method of preparing metal fluoride crystals that are suitable for making optical elements that can be used in below 200 nm lithographic equipment and processes. In accordance with the invention, metal fluoride particles, substantially all of which have a size of 1 mm or greater, are treated with an oxygen scavenger material just prior to being melted and used to grow a metal fluoride single crystal. In one embodiment of the invention a metal fluoride raw material is treated with an oxygen scavenger to remove oxygen containing impurities, liquefied and cooled to form a premelt material. The premelt material is then broken into particles having a range of sizes and separated by sieving or other separation methods known in the art into at least a group of particles substantially all of which have a size of 1 mm or larger and a group of particles having a size of less than 1 mm.