System and method for crystal growing
View Patent ↗To reduce the heat input to the bottom of the crucible and to control heat extraction independently of heat input, a shield can be raised between a heating element and a crucible at a controlled speed as the crystal grows. Other steps could include moving the crucible, but this process can avoid having to move the crucible. A temperature gradient is produced by shielding only a portion of the heating element; for example, the bottom portion of a cylindrical element can be shielded to cause heat transfer to be less in the bottom of the crucible than at the top, thereby causing a stabilizing temperature gradient in the crucible.
1. A method of growing crystals from a liquid in a crucible, said method comprising:
heating the crucible with a heating element;
extracting heat from the crucible using a heat exchanger in thermal contact with the crucible; and
moving a movable shield relative to the heating element and the crucible over a range of positions to reduce heat provided to portions of the crucible, the moving and extracting causing the crystal to solidify along a desired direction.
2. The method of claim 1 , wherein the extracting heat from the crucible includes moving insulation away from the support block.
3. The method of claim 1 , further comprising positioning the crucible on a support structure such that the crucible is supported from below and is not moved during the crystal growing process.
4. The method of claim 1 , further comprising independently controlling movement of the heat exchanger, an output of the heating element, and a position of the movable shield.
5. The method of claim 1 , wherein the heat exchanger moves away from the support structure, and thereafter the movable shield is moved to a position between the at least one heating element and the crucible.
6. The method of claim 1 , wherein the crucible is enclosed in a housing with a floor under the crucible, the moving including moving the shield through one or more openings in the floor.
7. The method of claim 1 , wherein the resulting crystal is at least about 300 kg.
8. The method of claim 1 , wherein the resulting crystal comprises a multicrystalline crystal.
9. The method of claim 1 , wherein the resulting crystal comprises a single crystal.
10. The method of claim 1 , wherein the method is performed without moving the crucible.