Method of loading a charge of polysilicon into a crucible
A method of loading a crucible includes loading a first layer of polysilicon chunks into the crucible and loading a second layer of granular polysilicon into the crucible to form a polysilicon charge such that the packing density of the polysilicon charge within the crucible is greater than 0.70.
1. A method of loading a crucible, comprising:
loading a first layer of polysilicon chunks into the crucible;
loading a second layer of granular polysilicon into the crucible; and
loading a third layer of polysilicon particles into the crucible such that the following equation is satisfied:
PD C =PD L +(1−PD L )PD M +(1−PD L )(1−PD M )PD S ,
wherein:
PD C is a packing density of a charge of polysilicon within the crucible;
PD L is a packing density of the polysilicon chunks;
PD M is a packing density of the polysilicon particles; and
PD S is a packing density of the polysilicon granules, and wherein the packing density of polysilicon within the crucible is greater than about 0.70.
2. A method of loading a crucible according to claim 1 , wherein the polysilicon particles are smaller than the polysilicon chunks and larger than the polysilicon granules.
3. A method of loading a crucible according to claim 1 , wherein the crucible is loaded such that the packing density of polysilicon within the crucible is between about 0.70 and about 0.90.
4. A method of loading a crucible according to claim 1 , further comprising classifying bulk polysilicon material into the polysilicon chunks having a large particle dimension and polysilicon granules having a small particle dimension, wherein a ratio of the large particle dimension to the small particle dimension is greater than about 7:1.
5. A method of loading a crucible according to claim 4 , wherein the ratio of the large particle dimension to the small particle dimension is about 10:1.
6. A method of loading a crucible according to claim 4 , wherein the ratio of the large particle dimension to the small particle dimension is about 100:1.
7. A method of loading a crucible according to claim 1 , wherein loading a second layer of granular polysilicon into the crucible includes loading the second layer of granular polysilicon after adding the first quantity of polysilicon chunks.
8. A method of loading a crucible according to claim 1 , further comprising alternately providing a plurality of layers of the polysilicon chunks and layers of the polysilicon granules.
9. A method of loading a crucible according to claim 8 , further comprising providing the layers of the polysilicon chunks and the layers of the polysilicon granules until a total weight of the polysilicon chunks and polysilicon granules within the crucible is at least 90 kilograms.
10. A method of loading a crucible according to claim 8 , wherein each layer of polysilicon chunks weighs about 10 kg to about 15 kg and each layer of granular polysilicon weighs about 10 kg to about 15 kg.
11. A method of loading a crucible according to claim 8 , wherein providing the layers includes providing a top layer of polysilicon chunks.
12. A method of loading a crucible according to claim 1 , wherein the crucible is loaded such that a height of the polysilicon charge does not extend past a rim of the crucible.
13. A method of loading a crucible according to claim 1 , further comprising exhausting polysilicon dust using a vacuum.
14. A crucible comprising:
a first layer of polysilicon chunks within the crucible;
a second layer of granular polysilicon within the crucible;
a third layer of polysilicon particles within the crucible;
wherein the following equation is satisfied:
PD C =PD L +(1−PD L )PD M +(1−PD L )(1−PD M )PD S ,
wherein:
PD C is the packing density of the charge of polysilicon within the crucible;
PD L is a packing density of the polysilicon chunks;
PD M is a packing density of the polysilicon particles; and
PD S is a packing density of the polysilicon granules; and
wherein the packing density of the combination of the first layer, the second layer, and the third layer of polysilicon within the crucible is greater than about 0.70.
15. A crucible according to claim 14 , wherein the polysilicon particles are smaller than the polysilicon chunks and larger than the polysilicon granules.
16. A crucible according to claim 14 , wherein the packing density of polysilicon within the crucible is between about 0.70 and about 0.90.