SYSTEMS AND METHODS FOR GROWING POLYCRYSTALLINE SILICON INGOTS
Systems and methods for growing polycrystalline silicon ingots are described. The systems and methods involve placing an initial charge of polysilicon in a crucible, using a direct solidification/heat exchanger method furnace to melt the initial charge to form a melt, and then introducing additional polysilicon to the melt while the melt and crucible are within the furnace. The additional polysilicon may be added to the crucible in order to bring the melt to any desired volume, including until the crucible is full or topped off. An augmenting mechanism, such as a hopper, may be used to introduce additional polysilicon to the melt. The hopper may have a silicon introduction controller that controls the introduction of polysilicon into the melt. Other embodiments are described.
1 . A system for growing polysilicon ingots, comprising:
a crucible adapted to receive an initial charge of polysilicon;
a furnace adapted to receive the crucible and melt the initial charge of polysilicon to form a polysilicon melt; and
an augmentor adapted to introduce additional polysilicon into the polysilicon melt while the melt and the crucible are within the furnace.
2 . The system of claim 1 , wherein the furnace defines an opening for receiving the augmentor.
3 . The system of claim 2 , wherein the augmentor comprises a hopper.
4 . The system of claim 3 , wherein the hopper comprises a chamber and a tube.
5 . The system of claim 1 , wherein the augmentor comprises a silicon introduction controller.
6 . The system of claim 5 , wherein the silicon introduction controller comprises a gate, a valve, a rotor, a conveyor belt, or an auger conveyor.
7 . The system of claim 1 , wherein the crucible comprises a quartz crucible.
8 . The system of claim 1 , wherein the augmentor is adapted to introduce the additional polysilicon into the polysilicon melt until the crucible is topped off by the additional polysilicon.
9 . A method for growing polysilicon ingots, comprising:
adding an initial charge of polysilicon to a crucible;
placing the initial charge and crucible into a furnace;
melting the initial charge of polysilicon to form a polysilicon melt;
adding additional polysilicon to the melt while the melt and crucible are within the furnace; and
allowing the crucible to cool.
10 . The method of claim 9 , wherein the additional polysilicon is added to the polysilicon melt by using an augmentor.
11 . The method of claim 10 , wherein the augmentor comprises a hopper.
12 . The method of claim 11 , wherein the hopper comprises a silicon introduction controller.
13 . The method of claim 12 , wherein the silicon introduction controller comprises a gate, a valve, a rotor, a conveyor belt, or an auger conveyor.
14 . The method of claim 11 , wherein the furnace defines an opening for receiving the hopper.
15 . The method of claim 9 , wherein adding additional polysilicon to the polysilicon melt comprises topping off the crucible with the additional polysilicon.