A lasing medium having a tailored dopant concentration and a method of fabrication thereof is disclosed. The lasing medium has a single crystal having a continuous body having a selected length, wherein the crystal comprises dopant distributed along the length of the body to define a dopant concentration profile. In one embodiment, the dopant concentration profile results in a uniform heating profile. A method of fabricating a laser crystal having a tailored dopant concentration profile includes arranging a plurality of polycrystalline segments together to form an ingot, the polycrystalline segments each having dopant distributed, providing a crystal seed at a first end of the ingot, and moving a heating element along the ingot starting from the first end to a second end of the ingot, the moving heating element creating a moving molten region within the ingot while passing therealong.

A lasing medium having a tailored dopant concentration and a method of fabrication thereof is disclosed. The lasing medium has a single crystal having a continuous body having a selected length, wherein the crystal comprises dopant distributed along the length of the body to define a dopant concentration profile. In one embodiment, the dopant concentration profile results in a uniform heating profile. A method of fabricating a laser crystal having a tailored dopant concentration profile includes arranging a plurality of polycrystalline segments together to form an ingot, the polycrystalline segments each having dopant distributed, providing a crystal seed at a first end of the ingot, and moving a heating element along the ingot starting from the first end to a second end of the ingot, the moving heating element creating a moving molten region within the ingot while passing therealong.

A single crystal manufacturing apparatus to grow a single crystal upward from a seed crystal, the apparatus including an insulated space thermally insulated from a space outside the single crystal manufacturing apparatus, an induction heating coil placed outside the insulated space, a thermal insulation plate that divides the insulated space into a first space including a crystal growth region to grow the single crystal and a second space above the first space and includes a hole above the crystal growth region, a heating element that is placed in the second space and generates heat by induction heating using the induction heating coil to heat the inside of the insulated space, and a support shaft to vertically movably support the seed crystal from below.

The process for manufacturing a silicon wafer includes steps for mounting a float zone silicon work piece for exfoliation, energizing a microwave device for generating an energized beam sufficient for penetrating an outer surface layer of the float zone silicon work piece, exfoliating the outer surface layer of the float zone silicon work piece with the energized beam, and removing the exfoliated outer surface layer from the float zone silicon work piece as the silicon wafer having a thickness less than 100 micrometers.

The process for manufacturing a silicon wafer includes steps for mounting a float zone silicon work piece for exfoliation, energizing a microwave device for generating an energized beam sufficient for penetrating an outer surface layer of the float zone silicon work piece, exfoliating the outer surface layer of the float zone silicon work piece with the energized beam, and removing the exfoliated outer surface layer from the float zone silicon work piece as the silicon wafer having a thickness less than 100 micrometers.

Disclosed is an electromagnetic casting method of polycrystalline silicon which is characterized in that polycrystalline silicon is continuously cast by charging silicon raw materials into a bottomless cold mold, melting the silicon raw materials using electromagnetic induction heating, and pulling down the molten silicon to solidify it, wherein the depth of solid-liquid interface before the start of the final solidification process is decreased by reducing a pull down rate of ingot in a final phase of steady-state casting. By adopting the method, the region of precipitation of foreign substances in the finally solidified portion of ingot can be reduced and cracking generation can be prevented upon production of a polycrystalline silicon as a substrate material for a solar cell.

Disclosed is an electromagnetic casting method of polycrystalline silicon which is characterized in that polycrystalline silicon is continuously cast by charging silicon raw materials into a bottomless cold mold, melting the silicon raw materials using electromagnetic induction heating, and pulling down the molten silicon to solidify it, wherein the depth of solid-liquid interface before the start of the final solidification process is decreased by reducing a pull down rate of ingot in a final phase of steady-state casting. By adopting the method, the region of precipitation of foreign substances in the finally solidified portion of ingot can be reduced and cracking generation can be prevented upon production of a polycrystalline silicon as a substrate material for a solar cell.