Methods for preparing a doped ingot
AssigneeGlobalWafers Co., Ltd.
InventorsRoberto Scala, Stephan Haringer, Franco Battan
Life of this patent
Estimating the term…
Abstract
Ingot puller apparatus for preparing silicon ingots that include a dopant feed system are disclosed. The dopant feed system include a dopant conduit having a porous partition member disposed across the dopant conduit. Solid dopant falls onto the partition member where it sublimes. The sublimed dopant is carried by inert gas through the partition member to contact and dope the silicon melt.
Claims20
A method for preparing a doped ingot comprising:
- preparing a melt of silicon in a crucible;
- feeding solid dopant into an inlet of a dopant conduit, the dopant conduit extending into a growth chamber in which an ingot is pulled from the melt, the solid dopant passing through a conduit chamber defined by the dopant conduit and onto a partition member disposed within the dopant conduit that extends across a width of the conduit chamber, the partition member being within the last 25% of a length of the dopant conduit;
- heating solid dopant supported by the partition member with radiant heat from the melt to sublime the solid dopant;
- introducing an inert gas into the dopant conduit, the inert gas mixing with sublimed dopant, the inert gas having sublimed dopant mixed therein passing through the partition member and being discharged through an outlet of the dopant conduit, a pressure of the inert gas being reduced upon passing through the partition member;
- contacting inert gas having sublimed dopant mixed therein with the melt to absorb dopant from the inert gas into the melt;
- and
- pulling a silicon ingot from the melt of silicon.
A method for preparing a doped ingot in an ingot puller apparatus comprising a crucible for holding a melt of silicon, a growth chamber for pulling a silicon ingot from the melt, and a dopant conduit for introducing dopant into the melt, the dopant conduit comprising one or more sidewalls, the one or more sidewalls forming a conduit chamber through which dopant passes, the conduit chamber having a width, the dopant conduit further comprising an inlet through which solid dopant is introduced into the dopant conduit, an outlet through which a gaseous dopant is discharged through the dopant conduit, and a partition member disposed between the inlet and the outlet and supporting solid dopant introduced through the inlet, the partition member extending across the width of the conduit chamber, the method comprising:
- forming a melt of silicon in the crucible;
- loading solid dopant onto the partition member, the partition member being positioned between about 1 mm and about 15 mm from a surface of the melt to heat the solid dopant by radiant heat from the melt to cause the solid dopant to sublime;
- introducing an inert gas into the conduit chamber, the inert gas mixing with sublimed dopant to form a doped inert gas;
- passing the doped inert gas through the partition member to cause dopant to contact and enter the melt;
- and
- pulling a doped ingot from the melt of silicon.
Dependencies are inferred from the claim text.