Method for feeding arsenic dopant into a silicon crystal growing apparatus
AssigneeMEMC Electronic Materials, Inc.
InventorsMassoud Javidi, Steve Garner
Life of this patent
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Abstract
A feed assembly and method of use thereof of the present invention is used for the addition of a high pressure dopant such as arsenic into a silicon melt for CZ growth of semiconductor silicon crystals. The feed assembly includes a vessel-and-valve assembly for holding dopant, and a feed tube assembly, attached to the vessel-and-valve assembly for delivering dopant to a silicon melt. An actuator is connected to the feed tube assembly and a receiving tube for advancing and retracting the feed tube assembly to and from the surface of the silicon melt. A brake assembly is attached to the actuator and the receiving tube for restricting movement of the feed tube assembly and locking the feed tube assembly at a selected position.
Claims10
A method for feeding arsenic dopant to a silicon melt in a silicon crystal growing apparatus having a crystal growing chamber comprising the steps of:
- placing granular solid arsenic dopant in a vessel attached to a feed tube, the feed tube comprising a fixed tube and a movable tube in concentric arrangement;
- lowering the moveable tube toward the silicon melt with an actuator connected to the moveable tube to selectively position the moveable tube at the upper surface of the silicon melt;
- and
- releasing the dopant from the vessel to allow dopant to travel down the feed tube and into the melt at the upper surface of the melt.
A method for feeding arsenic dopant to a silicon melt in a silicon crystal growing apparatus having a crystal growing chamber, comprising the steps of:
- placing granular solid arsenic dopant in a vessel attached to a feed tube comprising a fixed tube and a moveable quartz tube having an angled tip, the fixed tube and moveable quartz tube being in concentric arrangement;
- lowering the moveable tube toward the silicon melt with an actuator connected to the moveable tube to selectively position the moveable tube at an upper surface of the silicon melt;
- releasing the dopant from the vessel to allow the dopant to travel down the feed tube to a catch located in the moveable tube for catching the dopant material when it is released from the vessel;
- and
- introducing argon gas into the feed tube below the vessel causing sublimation of the dopant resulting in dopant laden argon exiting the angled tip of the moveable quartz tube at the upper surface of the silicon melt.
Dependencies are inferred from the claim text.