Infrared temperature control of Czochralski crystal growth

Apparatus for growing a crystal of controlled diameter by withdrawing a seed at a constant rate from a melt, said apparatus comprising:

• temperature sensing means for providing an output signal in response to the instantaneous melt temperature at a point on the surface of said melt adjacent to the crystal;
• means for heating the melt;
• means for energizing said heating means;
• and
• temperature control means responsive to the output signal of said temperature sensing means, said temperature control means determining an average of the output signal of said temperature sensing means and controlling said energizing means with respect to the average of the output signal to control the average temperature of the point on the melt adjacent to the crystal.

Apparatus for controlling the diameter of a crystal grown by a constant rate of withdrawal from a melt contained in a crucible, said apparatus comprising:

• an infrared sensor for determining the instantaneous temperature of a predetermined point on the surface of said melt;
• temperature control means responsive to the output of said infrared sensor, said temperature control means averaging the output of said infrared sensor to establish a temperature control signal;
• means for inductively heating said crucible;
• and
• means for supplying power to said inductive heating means in response to said temperature control signal.

Crystal growing apparatus for growing crystals of substantially constant diameter by withdrawing a crystal seed at a constant rate from a melt material, said apparatus comprising:

• an infrared sensor for determining the instantaneous melt temperature at a point on the ring of melt surrounding the crystal;
• means for averaging the instantaneous melt temperature determined by said infrared sensor;
• a power supply that provides a power output in response to the average temperature of said averaging means;
• and
• means for heating the melt in response to the power output of said power supply.

Crystal growing apparatus for growing a crystal of substantially constant diameter from a melt by controlling the temperature of the melt at the interface of the melt and the growing crystal and by controlling the rate of withdrawal of the crystal from the melt, said apparatus comprising:

• an infrared sensor for determining the instantaneous melt temperature at a point on the ring of melt at the interface of the melt and the growing crystal;
• means for averaging the instantaneous melt temperature determined by said infrared sensor;
• a power supply that provides a power output which is proportional to the average temperature of said averaging means;
• means for heating the melt in response to the power output of said power supply.

Crystal growing apparatus for growing a crystal of substantially constant diameter from a melt of material by maintaining a substantially constant melt temperature at the interface of the melt and the growing crystal and by maintaining a substantially constant rate of withdrawal of this crystal from the melt, said apparatus comprising:

• and infrared sensor for determining the instantaneous melt temperature at a point on the ring of melt at the interface of the melt surface and the growing crystal;
• means for averaging the instantaneous temperature at the point on the melt surface determined by said infrared sensor;
• a power supply that provides a power output which is proportional to the average temperature determined by said averaging means;
• and
• means for heating the melt in response to the power output of said power supply to maintain a substantially constant melt temperature at the interface of the melt and the growing crystal.