US 6,712,908 B2Granted

Purified silicon production system

AssigneeMidwest Research Institute

InventorsTihu Wang, Theodore F. Ciszek

Life of this patent

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Abstract

Method and apparatus for producing purified bulk silicon from highly impure metallurgical-grade silicon source material at atmospheric pressure. Method involves: (1) initially reacting iodine and metallurgical-grade silicon to create silicon tetraiodide and impurity iodide byproducts in a cold-wall reactor chamber; (2) isolating silicon tetraiodide from the impurity iodide byproducts and purifying it by distillation in a distillation chamber; and (3) transferring the purified silicon tetraiodide back to the cold-wall reactor chamber, reacting it with additional iodine and metallurgical-grade silicon to produce silicon diiodide and depositing the silicon diiodide onto a substrate within the cold-wall reactor chamber. The two chambers are at atmospheric pressure and the system is open to allow the introduction of additional source material and to remove and replace finished substrates.

Claims6

Dependent claims

A system for purifying metallurgical-grade silicon and depositing the purified silicon on a substrate, comprising:

a first chamber, the first chamber further comprising a bottom portion, a mid-portion and a top portion, a first inlet, a purge gas line, a first outlet positioned in the top portion, a second outlet positioned lower than the first outlet, a second inlet positioned below the second outlet, a first heater at least partially surrounding the bottom portion, the first heater selectively varying the amount of heat applied to the bottom portion, and a second heater at least partially surrounding a portion of the first chamber positioned below the first outlet and above the second inlet;
a second chamber, the second chamber further comprising a bottom portion, a mid-portion and a top portion, an inlet which is in fluid communication with, and is interconnected with the second outlet of the first chamber, a first outlet positioned in the top portion of the second chamber, a second outlet positioned below the first outlet in the second chamber, a third outlet positioned below the second outlet of the second chamber but above the bottom portion of the second chamber, and a heater at least partially surrounding the bottom portion of the second chamber;
and
a third chamber, the third chamber comprising an inlet, the inlet in fluid communication with, and interconnected with the second outlet of the second chamber, and an outlet, the outlet in fluid communication with, and interconnected with the second inlet of the first chamber.

1 more element

Dependencies are inferred from the claim text.

Facts

Application: 10/243,503Filed 13 Sep 2002 · division
Priority: 15 Jun 1999
Published: US 2003/0019429 A130 Jan 2003
Granted: 30 Mar 2004
Term ends: Not estimatedThe source records don’t support an estimate.

Classification15 codes

C30B 29/06
Elements: silicon
C01B 33/039
Purification: by conversion of the silicon into a compound, optional purification of the compound, and reconversion into silicon
C23C 16/24
Characterised by the deposition of inorganic material, other than metallic material: deposition of silicon only
C23C 16/4402
Means for minimising impurities, e.g. dust, moisture or residual gas, in the reaction chamber: reduction of impurities in the source gas

Family

Application09/334,166Parent of this continuation-in-part · filed 15 Jun 1999
Application09/941,490Parent of this division · filed 28 Aug 2001
US 2003/0019429 A1Pre-grant publication · published 30 Jan 2003
US 6,468,886 B2Parent of this division
Application09/941,490Parent of this continuation-in-part
US 6,281,098 B1Parent of this continuation-in-part
US 2002/0022088 A1Published application
US 6,712,908 B2This patent

From the US filing history. Foreign family members aren’t listed.