Apparatus and method for depositing silicon germanium films
First Claim
1. A method of depositing a silicon germanium layer with a targeted composition onto a substrate, comprising:
- injecting a silicon-containing precursor gas at a flow rate F1Si and a germanium-containing precursor gas at a flow rate F1Ge into a reaction chamber toward a substrate at a selected processing temperature with the chamber at a selected processing pressure, the precursor gases reacting to deposit a first silicon germanium layer with composition Si1−
xGex onto the substrate;
measuring x;
injecting a silicon-containing precursor gas at a flow rate F2Si and a germanium-containing precursor gas at a flow rate F2Ge into the reaction chamber toward a substrate at the selected processing temperature with the chamber at the selected processing pressure, the precursor gases reacting to deposit a second silicon germanium layer with composition Si1−
yGey onto the substrate, wherein y is a targeted value, the ratio F2Si/F2Ge substantially satisfying the equation
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Abstract
A new model is provided for the CVD growth of silicon germanium from silicon-containing and germanium-containing precursors. According to the new model, the germanium concentration x is related to the gas phase ratio according to the equation [x/(1−x)]2=mPGe/PSi, and m=Ae−E/(RT), where PSi is the partial pressure of the silicon-containing precursor, PGe is the partial pressure of the germanium-containing precursor, A is a constant, R is the universal gas constant, and T is the temperature. Methods and apparatuses are described for controlling CVD process parameters, associated with a series of reactions at constant or varied temperature, to achieve targeted germanium concentrations in silicon germanium films deposited onto semiconductor substrates. In particular, the new model can be used to calculate the resultant germanium concentration for selected precursor flow rates. The new model can also be used to control a precursor injection apparatus to achieve a desired germanium concentration.
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Citations
41 Claims
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1. A method of depositing a silicon germanium layer with a targeted composition onto a substrate, comprising:
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injecting a silicon-containing precursor gas at a flow rate F1Si and a germanium-containing precursor gas at a flow rate F1Ge into a reaction chamber toward a substrate at a selected processing temperature with the chamber at a selected processing pressure, the precursor gases reacting to deposit a first silicon germanium layer with composition Si1−
xGex onto the substrate;
measuring x;
injecting a silicon-containing precursor gas at a flow rate F2Si and a germanium-containing precursor gas at a flow rate F2Ge into the reaction chamber toward a substrate at the selected processing temperature with the chamber at the selected processing pressure, the precursor gases reacting to deposit a second silicon germanium layer with composition Si1−
yGey onto the substrate, wherein y is a targeted value, the ratio F2Si/F2Ge substantially satisfying the equation - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of depositing a silicon germanium layer with a targeted composition onto a substrate, comprising:
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providing a first substrate at a selected processing temperature in a reaction chamber at a selected processing pressure;
injecting SiH4 gas at a flow rate F1Si and GeH4 gas at a flow rate F1Ge into the reaction chamber toward the first substrate, the SiH4 and GeH4 gases reacting to deposit silicon germanium with composition Si1−
xGex onto the first substrate;
measuring x;
providing a second substrate at the selected processing temperature in the reaction chamber at the selected processing pressure; and
injecting SiH4 gas at a flow rate F2Si and GeH4 gas at a flow rate F2Ge into the reaction chamber toward the second substrate, the ratio F2Si/F2Ge substantially satisfying the equation wherein y is a targeted value of a composition Si1−
yGey of a silicon germanium layer deposited onto the second substrate by a reaction of the SiH4 and GeH4 gases.
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13. A method of calculating a parameter associated with a deposition process of a silicon germanium layer, comprising:
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providing a substrate in a reaction chamber;
injecting a silane gas with a molecular formula SinH2n+2 at a flow rate F1Si and a mixture of a germane gas and a carrier gas at a flow rate F1Gm into the reaction chamber toward the substrate, the silane and germane gases reacting to deposit silicon germanium with composition Si1−
xGex onto the substrate, the germane gas having a molecular formula GemH2m+2, the mixture having a dilution d1, wherein n and m are whole numbers;
measuring x;
selecting two parameters from the set comprising (1) a flow rate F2Si of a silane gas with a molecular formula SinH2n+2, (2) a flow rate F2Gm of a mixture of a carrier gas and a germane gas with a molecular formula GemH2m+2 and dilution d2, and (3) a concentration y in a silicon germanium composition Si1−
yGey;
assigning values to the two selected parameters; and
calculating the unselected parameter of said set from the equation or from one or more equations that are collectively mathematically equivalent to the above equation. - View Dependent Claims (14, 15)
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16. A method of depositing a silicon germanium film with a targeted composition onto a substrate, comprising:
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injecting SiH4 gas at a flow rate F1Si and GeH4 gas at a flow rate F1Ge into the reaction chamber toward a substrate at a first temperature T1 (in Kelvin), the SiH4 and GeH4 gases reacting to deposit a first silicon germanium film with composition Si1−
xGex onto the substrate;
measuring x;
injecting SiH4 gas at a flow rate F2Si and GeH4 gas at a flow rate F2Ge into the reaction chamber toward a substrate at a second temperature T2 (in Kelvin), the SiH4 and GeH4 gases reacting to deposit a second silicon germanium film with composition Si1−
yGey onto the substrate;
measuring y;
injecting SiH4 gas at a flow rate F3Si and GeH4 gas at a flow rate F3Ge into the reaction chamber toward a substrate at a third temperature T3 (in Kelvin), the ratio F3Si/F3Ge substantially satisfying the equation wherein z is a targeted value of a composition Si1−
zGez of a third silicon germanium film deposited onto a substrate at a temperature T3 (in Kelvin) by a reaction of SiH4 and GeH4 gases, wherein - View Dependent Claims (17)
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18. A method of calculating a parameter associated with a deposition process of a silicon germanium film, comprising:
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injecting silane gas at a flow rate F1Si and a mixture of a carrier gas and germane gas with a dilution d1 at a flow rate F1Gm into a reaction chamber toward a substrate at a first temperature T1 (in Kelvin), the silane and germane gases reacting to deposit a first silicon germanium film with composition Si1−
xGex onto the substrate, the silane and germane gases having molecular formulas SinH2n+2 and GemH2m+2, respectively, wherein n and m are whole numbers;
measuring x;
injecting silane gas with a molecular formula SinH2n+2 at a flow rate F2Si and a mixture of a carrier gas and germane gas with a dilution d2 at a flow rate F2Gm into the reaction chamber toward a substrate at a second temperature T2 (in Kelvin), the silane and germane gases reacting to deposit a second silicon germanium film with composition Si1−
yGey onto the substrate, the germane gas having a molecular formula GemH2m+2;
measuring y;
selecting three parameters from the set comprising (1) a flow rate F3Si of a silane gas with a molecular formula SinH2n+2, (2) a flow rate F3Gm of a mixture of a carrier gas and germane gas with a dilution d3, the germane gas having a molecular formula GemH2m+2, (3) a temperature T3 (in Kelvin), and (4) a concentration z in a silicon germanium composition Si1−
zGez;
assigning values to the three selected parameters; and
calculating the unselected parameter of said set from one of the two equations or from one or more equations that are collectively mathematically equivalent to either of the above equations, wherein - View Dependent Claims (19, 20)
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21. An apparatus for depositing a silicon germanium layer with a targeted composition onto a substrate, comprising:
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a reaction chamber containing a substrate support structure;
a source of a silicon-containing precursor gas;
a source of a germanium-containing precursor gas;
an injector assembly connected to the gas sources for injecting the silicon-containing and germanium-containing gases at controllable flow rates into the reaction chamber toward a substrate supported by the substrate support structure; and
a computer unit configured to store information associated with a first reaction of the silicon-containing precursor gas injected into the chamber at a flow rate F1Si and the germanium-containing precursor gas injected into the chamber at a flow rate F1Ge by the injector assembly to deposit a first silicon germanium layer with composition Si1−
xGex onto a substrate supported by the substrate support structure, the stored information from the first reaction comprising F1Si, F1Ge, and x, the computer unit also configured to store information associated with a second reaction of a silicon-containing precursor gas at a flow rate F2Si and a germanium-containing precursor gas at a flow rate F2Ge to deposit a second silicon germanium layer with composition Si1−
yGey, the stored information from the second reaction comprising only two parameters of the set consisting of F2Si, F2Ge, and y;
wherein the computer unit is additionally configured to calculate the unstored parameter of the set consisting of F2Si, F2Ge, and y from the equation - View Dependent Claims (22, 23, 24)
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25. An apparatus for depositing a silicon germanium layer with a targeted composition onto a substrate, comprising:
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a reaction chamber containing a substrate support structure;
a source of SiH4 gas;
a source of GeH4 gas;
an injector assembly connected to the SiH4 and GeH4 gas sources for injecting SiH4 gas and GeH4 gas at controllable flow rates into the reaction chamber toward a substrate supported by the substrate support structure; and
a computer unit configured to store information associated with a first reaction of SiH4 gas injected into the chamber at a flow rate F1Si and GeH4 gas injected into the chamber at a flow rate F1Ge by the injector assembly to deposit a first silicon germanium layer with composition Si1−
xGex onto a first substrate supported by the substrate support structure, the stored information from the first reaction comprising F1Si, F1Ge, and x, the computer unit also configured to store information associated with a second reaction of SiH4 gas at a flow rate F2Si and GeH4 gas at a flow rate F2Ge to deposit a second silicon germanium layer with composition Si1−
yGey, the stored information from the second reaction comprising only two parameters of the set consisting of F2Si, F2Ge, and y;
wherein the computer unit is additionally configured to calculate the unstored parameter of the set consisting of F2Si, F2Ge, and y from the equation - View Dependent Claims (26)
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27. An apparatus for calculating a parameter associated with a deposition process of a silicon germanium layer, comprising:
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a reaction chamber containing a substrate support structure;
a source of silane gas having a molecular formula SinH2n+2, wherein n is a whole number;
a source of a mixture of a carrier gas and a germane gas with a dilution d1, the germane gas having a molecular formula GemH2m+2, wherein m is a whole number;
an injector assembly connected to the gas sources for injecting the silane gas and the mixture of carrier and germane gas at controllable flow rates into the reaction chamber toward a substrate supported by the substrate support structure; and
a control system configured to store information associated with a reaction of the silane gas injected into the chamber at a flow rate F1Si and the carrier/germane gas mixture injected into the chamber at a flow rate F1Gm by the injector assembly to deposit a silicon germanium layer with composition Si1−
xGex onto a substrate supported by the substrate support structure, the stored information comprising F1Si, F1Gm, and x;
wherein the control system is additionally configured to store assigned values of two selected parameters from the set comprising (1) a flow rate F2Si of a silane gas with a molecular formula SinH2n+2, (2) a flow rate F2Gm of a mixture of a carrier gas and a germane gas with a molecular formula GemH2m+2 and dilution d2, and (3) a concentration y in a silicon germanium composition Si1−
yGey, the control system configured to calculate the unselected parameter of said set from the equationor from one or more equations that are collectively mathematically equivalent to the above equation. - View Dependent Claims (28, 29)
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30. An apparatus for depositing a silicon germanium layer with a targeted composition onto a substrate, comprising:
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a reaction chamber containing a substrate support structure;
a source of silane gas with a molecular formula SinH2n+2, wherein n is a whole number;
a source of germane gas with a molecular formula GemH2m+2, wherein m is a whole number;
a gas injector assembly connected to the gas sources for injecting the silane and germane gases at controllable flow rates into the reaction chamber toward a substrate supported by the substrate support structure;
a control system configured to store information associated with a first reaction of the silane gas injected into the chamber at a flow rate F1Si and the germane gas injected into the chamber at a flow rate F1Ge by the gas injector assembly to deposit a first silicon germanium layer with composition Si1−
xGex onto a substrate supported by the substrate support structure at a first substrate temperature T1 (in Kelvin), the control system also configured to store information associated with a second reaction of the silane gas injected into the chamber at a flow rate F2Si and the germane gas injected into the chamber at a flow rate F2Ge by the gas injector assembly to deposit a second silicon germanium layer with composition Si1−
yGey onto a substrate supported by the substrate support structure at a second substrate temperature T2 (in Kelvin), the stored information of the first and second reactions comprising F1Si, F1Ge, T1, x, F2Si, F2Ge, T2, and y, the control system being configured to store information associated with a third reaction of silane gas at a flow rate F3Si and germane gas at flow rate F3Ge to deposit a third silicon germanium layer with composition Si1−
zGez onto a substrate at a third substrate temperature T3 (in Kelvin), the stored information of the third reaction comprising only two parameters of the set consisting of F3Si, F3Ge, and z;
wherein the control system is additionally configured to calculate the unstored parameter of the set consisting of F3Si, F3Ge, and z from the equations - View Dependent Claims (31, 32, 33, 34, 35, 36, 37, 38, 39)
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40. An apparatus for calculating a parameter associated with a deposition process of a silicon germanium film, comprising:
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a reaction chamber containing a substrate support structure;
a source of silane gas having a molecular formula SinH2n+2, wherein n is a whole number;
a source of a mixture of a carrier gas and germane gas with a dilution d, the germane gas having a molecular formula GemH2m+2, wherein m is a whole number;
a gas injector assembly connected to the gas sources for injecting the silane gas and the carrier/germane gas mixture at controllable flow rates into the reaction chamber toward a substrate supported by the substrate support structure;
a control system configured to store information associated with a first reaction of the silane gas injected into the chamber at a flow rate F1Si and the carrier/germane gas mixture injected into the chamber at a flow rate F1Gm by the gas injector assembly to deposit a silicon germanium film with composition Si1−
xGex onto a substrate supported by the substrate support structure at a first substrate temperature T1, the control system also configured to store information associated with a second reaction of the silane gas injected into the chamber at a flow rate F2Si and the carrier/germane gas mixture injected into the chamber at a flow rate F2Gm by the gas injector assembly to deposit a silicon germanium film with composition Si1−
yGey onto a substrate supported by the substrate support structure at a second substrate temperature T2, the stored information comprising F1Si, F1Gm, T1, x, F2Si, F2Gm, T2, and y;
wherein the control system is additionally configured to store assigned values of three selected parameters from the set comprising (1) a flow rate F3Si of silane gas with a molecular formula SinH2n+2, (2) a flow rate F3Gm of a mixture of a carrier gas and germane gas with a dilution d3, the germane gas having a molecular formula GemH2m+2, (3) a temperature T3 (in Kelvin), and (4) a concentration z in a silicon germanium composition Si1−
zGez, the control system configured to calculate the unselected parameter of said set from one of the two equationsor from one or more equations that are collectively mathematically equivalent to either of the above equations, wherein - View Dependent Claims (41)
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Specification