Methods for Selective and Conformal Epitaxy of Highly Doped Si-containing Materials for Three Dimensional Structures
First Claim
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1. A method for forming an epitaxial film on a three-dimensional structure in a chemical vapor deposition system, comprising:
- providing a three-dimensional structure disposed within a chamber;
introducing a silicon precursor to said chamber at a temperature of less than 600°
C., wherein said silicon precursor is accompanied with a carrier gas wherein said carrier gas has a flow rate of 10 to 200 times greater than the flow rate of said silicon precursor; and
forming an epitaxial film comprising multiple epilayers by way of a cyclical deposition and etch process wherein each epilayer is formed as a result of (i) exposing said three-dimensional structure to a process gas containing said silicon precursor to deposit a silicon-containing epilayer across the surfaces of said three-dimensional structure wherein said process carrier gas flows at a rate of about 100 to 2000 times greater than said silicon precursor and (ii) exposing said deposited silicon layer to an etchant gas so that the net growth of each epilayer is no great than 5-25 Å
per cycle.
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Abstract
The present invention addresses the key challenges in FinFET fabrication, that is, the fabrications of thin, uniform fins and also reducing the source/drain series resistance. More particularly, this application relates to FinFET fabrication techniques utilizing tetrasilane to enable conformal deposition with high doping using phosphate, arsenic and boron as dopants thereby creating thin fins having uniform thickness (uniformity across devices) as well as smooth, vertical sidewalls, while simultaneously reducing the parasitic series resistance.
323 Citations
24 Claims
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1. A method for forming an epitaxial film on a three-dimensional structure in a chemical vapor deposition system, comprising:
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providing a three-dimensional structure disposed within a chamber; introducing a silicon precursor to said chamber at a temperature of less than 600°
C., wherein said silicon precursor is accompanied with a carrier gas wherein said carrier gas has a flow rate of 10 to 200 times greater than the flow rate of said silicon precursor; andforming an epitaxial film comprising multiple epilayers by way of a cyclical deposition and etch process wherein each epilayer is formed as a result of (i) exposing said three-dimensional structure to a process gas containing said silicon precursor to deposit a silicon-containing epilayer across the surfaces of said three-dimensional structure wherein said process carrier gas flows at a rate of about 100 to 2000 times greater than said silicon precursor and (ii) exposing said deposited silicon layer to an etchant gas so that the net growth of each epilayer is no great than 5-25 Å
per cycle. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A method for forming an epitaxial film on a FinFET device in a chemical vapor deposition system, comprising:
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providing the FinFET device disposed within a chamber; introducing a silicon precursor to said chamber at a temperature of less than 600°
C., wherein said silicon precursor is accompanied with a carrier gas wherein said carrier gas has a flow rate of 10 to 200 times greater than the flow rate of said a silicon precursor;forming an epitaxial film comprising multiple epilayers by way of a cyclical deposition and etch process wherein each epilayer is formed as a result of (i) exposing said FinFET device to a process gas containing said silicon precursor to deposit a silicon-containing epilayer across the surfaces of the FinFET device wherein said process carrier gas flows at a rate of about 100 to 2000 times greater than said silicon precursor and (ii) exposing said deposited silicon layer to an etchant gas so that the net growth of each epilayer is no great than 5-25 Å
per cycle; andexposing the epitaxial layers periodically to an HCl etching gas purified to about 10 ppb under a pressure in the range of 100-700 Torr wherein said FinFET device comprises two or more fins have vertical surface wherein said epilayers forming on the vertical surface of the fins remain vertical.
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24. A method for forming an epitaxial film on a FinFET device in a chemical vapor deposition system, comprising:
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providing the FinFET device disposed within a chamber; introducing tetrasilane to said chamber at a temperature of less than 600°
C., wherein said tetrasilane is accompanied with a carrier gas wherein said carrier gas has a flow rate of 10 to 200 times greater than the flow rate of said tetrasilane;forming an epitaxial film comprising multiple epilayers by way of a cyclical deposition and etch process wherein each epilayer is formed as a result of (i) exposing said FinFET device to a process gas containing said silicon precursor to deposit a silicon-containing epilayer across the surfaces of the FinFET device wherein said process carrier gas flows at a rate of about 100 to 2000 times greater than said tetrasilane and (ii) exposing said deposited tetrasilane layer to an etchant gas so that the net growth of each epilayer is no great than 5-25 Å
per cycle; andexposing the epitaxial layers periodically to an HCl etching gas purified to about 10 ppb under a pressure in the range of 100-700 Torr wherein said FinFET device comprises two or more fins have vertical surface wherein said epilayers forming on the vertical surface of the fins remain vertical.
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Specification