Silica glass crucible
To provide a silica glass crucible, wherein there are no problems of generating a sinking and buckling when said crucible is used for pulling up silicon single crystal at a high temperature. The silica glass crucible used for pulling up the silicon single crystal, wherein at least an outer surface of a wall part of the crucible is covered with fine grooves having a length of less than 200 μm, a width of less than 30 μm and a depth of from more than 3 μm to less than 30 μm. Preferably, said fine groves are formed by carrying out a sand-blast treatment and a hydrofluoric acid etching and exist on more than 10% of the outer surface of the crucible, and a sliding frictional coefficient of the outer surface of the crucible to a carbon at 1500 degree C. is more than 0.6.
1. A silica glass crucible used for pulling silicon single crystal, comprising:
a silica glass crucible having a wall part, an open diameter, an inner surface, and an outer surface; and
a graphite susceptor adhered to the outer surface of the silica glass crucible;
wherein at least an outer surface of the wall part of the crucible is covered with fine grooves having a length of from 10 μm, to 200 μm, a width of from 10 μm to 30 μm and a depth of from more than 3 μm to less than 30 μm; and
wherein a sliding frictional coefficient of the outer surface of the crucible to the graphite susceptor at 1500° C. is more than 0.6, and
wherein a number of projections having a height of 0.1 mm or more is an average of less than 5 /mm 2 per unit area on the outer surface of the crucible.
2. The silica glass crucible according to claim 1 ,
wherein the fine grooves exist on more than 10% of the whole outer surface of the crucible.
3. The silica glass crucible according to claim 1 ,
wherein the outer surface of the crucible is covered with the fine grooves by carrying out a sand-blast treatment and a hydrofluoric acid etching on the outer surface.
4. A silica glass crucible used for pulling silicon single crystal, comprising:
a silica glass crucible having a wall part, an open diameter, an inner surface, and an outer surface; and
a graphite susceptor adhered to the outer surface of the silica glass crucible;
wherein at least an outer surface of the wall part of the crucible is covered with fine grooves having a length of from 10 μm to 200 μm, a width of from 10 μm to 30 μm and a depth of from more than 3 μm to less than 30 μm, and
the fine grooves exist on more than 10% of the whole outer surface of the crucible, and
a sliding frictional coefficient of the outer surface of the crucible to the graphite susceptor at 1500° C. is more than 0.6, and
wherein the outer surface of the crucible has projections having a height of 0.1 mm or more and the number of projections is an average of less than 5 /mm 2 per unit area on the outer surface of the crucible.
5. The silica glass crucible according to claim 1 , wherein the fine grooves have a depth of from more than 3 μm to 10 μm.
6. The silica glass crucible according to claim 1 , wherein the fine grooves have a length of 10 to 100 μm.
7. The silica glass crucible according to claim 4 , wherein the fine grooves have a depth of from more than 3 μm to 10 μm.
8. The silica glass crucible according to claim 4 , wherein the fine grooves have a length of 10 to 100 μm.
9. The silica glass crucible according to claim 1 , wherein the fine grooves are present only on the outer surface of the crucible.
10. The silica glass crucible according to claim 4 , wherein the fine grooves are present only on the outer surface of the crucible.
11. The silica glass crucible according to claim 1 , wherein the fine grooves exist on more than 50% of the whole outer surface of the crucible.
12. The silica glass crucible according to claim 4 , wherein the fine grooves exist on more than 50% of the whole outer surface of the crucible.