SIO probe for real-time monitoring and control of oxygen during czochralski growth of single crystal silicon
First Claim
1. A method for determining the amount of SiO present in an atmosphere over a pool of molten silicon, the method comprisingwithdrawing a sample containing SiO from the atmosphere over the pool of molten silicon, reacting SiO present in the sample with a reactant to form a detectable reaction product,determining the amount of reaction product formed, andcorrelating the determined amount of reaction product to the amount of SiO present in the atmosphere.
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Abstract
Methods for quantifying, in near real-time, the amount of silicon oxide (SiO) volatilized from a pool of molten silicon such as a Czochralski silicon melt and present in the atmosphere over the melt are disclosed. A preferred method includes reacting a gas sample containing SiO withdrawn from the atmosphere over the molten silicon with a reactant to form a detectable reaction product, determining the amount of reaction product formed, and correlating the determined amount of reaction product to the amount of SiO present in the atmosphere. The quantification of SiO is used for monitoring and/or controlling the amount of oxygen in the molten silicon or the oxygen content in single crystal silicon being drawn from the molten silicon. A SiO reaction probe and a system using the probe for monitoring and/or controlling oxygen are also disclosed.
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Citations
30 Claims
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1. A method for determining the amount of SiO present in an atmosphere over a pool of molten silicon, the method comprising
withdrawing a sample containing SiO from the atmosphere over the pool of molten silicon, reacting SiO present in the sample with a reactant to form a detectable reaction product, determining the amount of reaction product formed, and correlating the determined amount of reaction product to the amount of SiO present in the atmosphere.
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7. A method for determining the amount of oxygen in a pool of molten silicon, the method comprising
quantifying the amount of SiO present in an atmosphere over the pool of molten silicon, and correlating the quantified amount of SiO to the amount of oxygen in the molten silicon.
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9. A method for determining the amount of oxygen in a pool of molten silicon, the method comprising
withdrawing a sample containing SiO from an atmosphere over the molten silicon, reacting SiO present in the sample with a reactant to form a detectable reaction product, determining the amount of reaction product formed, and correlating the determined amount of reaction product to the amount of oxygen in the pool of molten silicon.
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10. A method for determining, in near real-time, the oxygen content in a single crystal silicon ingot being drawn from a pool of molten silicon, the method comprising
quantifying the amount of SiO present in an atmosphere over the pool of molten silicon, and correlating the quantified amount of SiO to the oxygen content in the single crystal silicon ingot.
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12. A method for determining, in near real-time, the oxygen content in a single crystal silicon ingot being drawn from a pool of molten silicon, the method comprising
withdrawing a sample containing SiO from an atmosphere over the pool of molten silicon, reacting SiO present in the sample with a reactant to form a detectable reaction product, determining the amount of reaction product formed, and correlating the determined amount of reaction product to the oxygen content in the single crystal silicon ingot.
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13. A method for controlling, in near real-time, the oxygen content in a single crystal silicon ingot being drawn from a pool of molten silicon under a set of process conditions that affect the oxygen content in the ingot, the method comprising
quantifying the amount of SiO present in an atmosphere over the pool of molten silicon while the silicon ingot is being drawn, and effecting a change in at least one process condition that affects the oxygen content in the silicon ingot, the sense and magnitude of the change being based on the quantified amount of SiO present in the atmosphere.
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15. A method for controlling, in near real-time, the oxygen content in a single crystal silicon ingot being drawn from a pool of molten silicon under a set of process conditions that affect the oxygen content in the ingot, the method comprising
withdrawing a sample containing SiO from an atmosphere over the pool of molten silicon, reacting SiO present in the sample with a reactant to form a detectable reaction product, determining the amount of reaction product formed, and effecting a change in at least one process condition that affects the oxygen content in the silicon ingot, the sense and magnitude of the change being based on the determined amount of reaction product.
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22. A probe for use in reacting SiO present in a gas sample withdrawn from an atmosphere over a pool of molten silicon with a reactant to form a detectable reaction product, the probe being suitable for use in a system for determining or controlling, in near-real time, the amount of SiO present in the atmosphere over the molten silicon, the amount of oxygen in the molten silicon or the oxygen content of a single crystal silicon ingot drawn from the molten silicon, the probe comprising
a reaction chamber defined in a body of the probe, the probe body being made of a material having a melting point greater than about 1500° - C. and being non-contaminating to the molten silicon when positioned over the pool of molten silicon,
an inlet port in fluid communication with the chamber and adapted for fluid communication with the atmosphere for withdrawing a sample containing SiO from the atmosphere into the chamber, and an outlet port in fluid communication with the chamber and adapted for fluid communication with a detector for determining the amount of reaction product formed. - View Dependent Claims (23, 24, 25)
- C. and being non-contaminating to the molten silicon when positioned over the pool of molten silicon,
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26. A system for use in determining or controlling, in near-real time, the amount of SiO present in an atmosphere over a pool of molten silicon contained within a quartz crucible, the amount of oxygen in the molten silicon or the oxygen content of a single crystal silicon ingot drawn from the molten silicon according to the Czochraski method, the system comprising
a SiO reaction probe located within a Czochraski crystal puller in the atmosphere over the pool of molten silicon for reacting SiO present in a gas sample withdrawn from the atmosphere with a reactant to form a detectable reaction product, the probe comprising a reaction chamber defined in a body of the probe, the probe body being made of a material having a melting point greater than about 1500° - C. and being non-contaminating to the molten silicon, an inlet port in fluid communication with the chamber and adapted for fluid communication with the atmosphere for withdrawing a sample containing SiO from the atmosphere into the chamber, an outlet port in fluid communication with the chamber and adapted for fluid communication with a detector for determining the amount of reaction product formed, and a reactant material contained within the chamber, the reactant material being capable of reacting with SiO present in the sample drawn into the chamber through the inlet port to form a detectable reaction product, and
a detector for determining the amount of reaction product formed. - View Dependent Claims (27, 28)
- C. and being non-contaminating to the molten silicon, an inlet port in fluid communication with the chamber and adapted for fluid communication with the atmosphere for withdrawing a sample containing SiO from the atmosphere into the chamber, an outlet port in fluid communication with the chamber and adapted for fluid communication with a detector for determining the amount of reaction product formed, and a reactant material contained within the chamber, the reactant material being capable of reacting with SiO present in the sample drawn into the chamber through the inlet port to form a detectable reaction product, and
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29. A method for determining, in near real-time, the oxygen content in a single crystal silicon ingot being drawn from a pool of molten silicon, the method comprising
withdrawing a sample containing SiO from an atmosphere over the pool of molten silicon, reacting SiO present in the sample with graphite to form gaseous carbon monoxide and SiC, determining the amount of carbon monoxide formed, and correlating the determined amount of carbon monoxide to the oxygen content in the single crystal silicon ingot.
Specification