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Silica crucibles containing an inner layer which is substantially pure and substantially bubble-free and methods for making such crucibles. The inner layer is also substantially stable against roughening and spot devitrification. The inner layer is formed by making a web structure which is then conv

Silica crucibles containing an inner layer which is substantially pure and substantially bubble-free and methods for making such crucibles. The inner layer is also substantially stable against roughening and spot devitrification. The inner layer is formed by making a web structure which is then converted to a continuous layer, thereby minimizing or eliminating bubble formation. The inner layer is also formed using a gettering agent which getters alkaline and alkaline-earth elements while the inner layer is formed. The alkaline and alkaline-earth elements are gettered on an innermost portion of the inner layer which is later removed, leaving an inner layer with relatively few impurities. When used in a CZ-crystal growing process, the inner surface of the crucible remains smooth and substantially no bubbles grow in the inner layer.

대표청구항 ▼

1. A method for making a silica crucible, comprising: providing a silica web structure containing a gettering agent; converting the web structure to a substantially continuous inner layer so an innermost portion of the inner layer contains a portion of the gettering agent; providing an outer la

1. A method for making a silica crucible, comprising: providing a silica web structure containing a gettering agent; converting the web structure to a substantially continuous inner layer so an innermost portion of the inner layer contains a portion of the gettering agent; providing an outer layer; and removing the innermost portion. 2. The method of claim 1, wherein the gettering agent comprises aluminum. 3. The method of claim 2, wherein the concentration of aluminum is greater than about 10 ppm. 4. The method of claim 1, wherein the gettering agent getters alkaline and alkaline earth group impurities. 5. The method of claim 1, including providing the inner layer by forming a silica web structure and then converting the structure to a substantially continuous layer. 6. The method of claim 5, including forming the silica web structure by providing quartz grain containing the gettering agent in a rotating mold and quickly heating an inner portion of the grain at a high power. 7. The method of claim 6, where the heating is performed for about 8 to about 30 seconds at a power ranging from about 500 KVA to about 900 KVA. 8. The method of claim 5, including converting the web structure by heating until the strands of the web structure are substantially merged. 9. The method of claim 6, including providing the outer layer by sintering the outer portion of the grain in the rotating mold. 10. The method of claim 1, including removing the inner portion of the inner layer by an etching process. 11. The method of claim 10, wherein the etching process uses HF acid.