Pressurized skull crucible for crystal growth using the Czochralski technique

A system receiving a pressurized gas, the system comprising:

• a pressure vessel for containing the pressurized gas;
• a cooling unit situated in the pressure vessel, having cooled surfaces defining an enclosure with at least one opening;
• a charge material positioned inside of the enclosure of the cooling unit and exposed through the opening of the enclosure to pressure exerted by the gas contained in the pressure vessel;
• an induction heating element situated in the pressure vessel, for generating radio-frequency (rf) radiation to heat an interior portion of the charge material to form a melt zone that is contained by a relatively cool, exterior portion of the charge material that is closer relative to the melt zone, to the cooled surfaces of the cooling unit;
• a shield situated in the pressure vessel in operation of the apparatus, and arranged between the induction heating element and a wall of the pressure vessel, the shield preventing the rf radiation generated by the induction heating element from significantly heating the pressure vessel's wall:
• a seed crystal;
• and
• a pull rod situated in the pressure vessel and having an end that holds the seed crystal, for moving the seed crystal into contact with the melt zone of the charge material and for moving the seed crystal away from the charge material to grow a crystal from the melt zone of the charge material.

A method comprising the steps of:

• a) heating an interior portion of a charge material body with radio-frequency (rf) radiation to melt the interior portion;
• b) during performance of the step (a), cooling an exterior portion of the charge material body so that the exterior portion is in a solid phase and contains the molten interior portion;
• c) pressurizing the charge material body in a pressure vessel with a gas during performance of the steps (a) and (b);
• d) shielding the pressure vessel from the rf radiation used to heat the interior portion in the step (a);
• e) moving a seed crystal into contact with the molten interior portion of the charge material;
• and
• f) moving the seed crystal away from the charge material body to pull an elongated crystal from the molten interior portion of the charge material body.

An apparatus for growing a crystal from a charge material with a seed crystal, the apparatus coupled to receive electric power and coolant, the apparatus comprising:

• a pressure vessel for containing a pressurized gas;
• a cooling unit for situation in the pressure vessel, having cooled surfaces defining an enclosure to receive the charge material;
• an induction heating element for situation in the pressure vessel, for heating an interior portion of the charge material to form a melt zone that is contained by a relatively cool, exterior portion of the charge material that is closer relative to the melt zone, to the cooled surfaces of the cooling unit, the heating element defining a conduit having two opposite terminal ends through which the coolant passes;
• a feedthrough extending through a wall of the pressure vessel, and having a first end situated inside of the pressure vessel, that is coupled to the heating element, and a second end opposite the first end, situated outside of the pressure vessel, the feedthrough having first and second conductors that are coaxial at least in a portion of the feedthrough that extends through the pressure vessel wall, the first and second conductors of the feedthrough coupled to respective terminal ends of the heating element to supply the electric power to the heating element and to circulate the coolant through the heating element;
• and
• a pull rod situated in the pressure vessel, for holding the seed crystal in proximity to the charge material contained in the cooling unit.