IMPLEMENTING ATOMIC LAYER DEPOSITION FOR GATE DIELECTRICS
20170110313 ยท 2017-04-20
Inventors
- Fu Tang (Gilbert, AZ, US)
- Xiaoqiang Jiang (Tempe, AZ, US)
- Qi Xie (Lueven, BE)
- Michael Eugene Givens (Scottsdale, AZ, US)
- Jan Willem Maes (Wilrijk, BE)
- Jerry Chen (Chandler, AZ, US)
Cpc classification
H10D62/83
ELECTRICITY
C23C16/45529
CHEMISTRY; METALLURGY
H01L21/28194
ELECTRICITY
H10D64/691
ELECTRICITY
H01L21/02211
ELECTRICITY
International classification
H01L21/02
ELECTRICITY
H01L29/20
ELECTRICITY
H01L29/16
ELECTRICITY
Abstract
A method for depositing a thin film onto a substrate is disclosed. In particular, the method forms a transitional metal silicate onto the substrate. The transitional metal silicate may comprise a lanthanum silicate or yttrium silicate, for example. The transitional metal silicate indicates reliability as well as good electrical characteristics for use in a gate dielectric material.
Claims
1. A method of forming a film comprising: providing a substrate for processing in a reaction chamber; performing a silicon precursor deposition onto the substrate; and performing a metal precursor deposition onto the substrate; wherein the silicon precursor deposition step is performed X times; wherein the metal precursor deposition step is performed Y times; wherein a transition metal silicate film is formed; wherein a metal precursor from the metal precursor deposition step comprises a metal atom bonded to a nitrogen atom or a carbon atom.
2. The method of claim 1, wherein the performing the silicon precursor deposition step further comprises: pulsing a silicon precursor; purging the silicon precursor from the reaction chamber with a purge gas; pulsing an oxidizing precursor; and purging the oxidizing precursor from the reaction chamber with the purge gas.
3. The method of claim 2, wherein the silicon precursor comprises at least one of: a silicon halide based precursor such as Silicon tetrachloride (SiCl.sub.4), trichloro-silane (SiCl.sub.3H), dichloro-silane (SiCl.sub.2H.sub.2), monochloro-silane (SiClH.sub.3), hexachlorodisilane (HCDS), octachlorotrisilane (OCTS), silicon iodides, or silicon bromides; an amino-based precursor, such as Hexakis(ethylamino)disilane (AHEAD) and SiH[N(CH.sub.3).sub.2].sub.3(3DMASi); Bis(dialkylamino)silanes, such as BDEAS (bis(diethylamino)silane); a mono(alkylamino)silanes, such as di-isopropylaminosilane; or an oxysilane based precursor, such as tetraethoxysilane Si(OC.sub.2H.sub.5).sub.4.
4. The method of claim 2, wherein the oxidizing precursor comprises at least one of: water (H.sub.2O); hydrogen peroxide (H.sub.2O.sub.2); oxygen (O.sub.2); ozone (O.sub.3); oxygen plasma; or methyl alcohol (CH.sub.3OH).
5. The method of claim 1, wherein the performing the metal precursor deposition step further comprises: pulsing a metal precursor; purging the metal precursor from the reaction chamber with a purge gas; pulsing an oxidizing precursor; and purging the oxidizing precursor from the reaction chamber with the purge gas.
6. The method of claim 5, wherein the metal precursor comprises at least one of: lanthanum; yttrium; an amidinate-based precursor, such as Lanthanum formamidinate (La(FAMD).sub.3), tris(N,N-diisopropylacetamidinato)lanthanum (La(iPrAMD).sub.3), or Tris(N,N-diisopropylacetamidinato) Yttrium (TDIPAY); a Cp(cyclopentadienyl)-based precursor, such as Tris(isopropyl-cyclopentadienyl) lanthanum (La(iPrCp).sub.3), Y(EtCp).sub.3, or tris(methylcyclopentadienyl)yttrium (Y(MeCp).sub.3); an amido-based chemistry, such as tris(bistrimethylsilylamido)-lanthanum (La[N(SiMe.sub.3).sub.2].sub.3); a diketonate based precursor, such as (La(THD).sub.3), (Y(THD).sub.3), or tris(2,2,6,6-tetramethyl-3,5-octanedionato)Yttrium (Y(tmod).sub.3); or an amide-based precursor, such as Tris[N,N-bis(trimethylsilyl)amide]yttrium.
7. The method of claim 5, wherein the oxidizing precursor comprises at least one of: water (H.sub.2O); hydrogen peroxide (H.sub.2O.sub.2); oxygen (O.sub.2); ozone (O.sub.3); oxygen plasma; atomic oxygen (0); oxygen radicals; or methyl alcohol (CH.sub.3OH).
8. The method of claim 2, wherein the purge gas comprises at least one of: nitrogen (N.sub.2) and Argon (Ar).
9. The method of claim 5, wherein the purge gas comprises at least one of: nitrogen (N.sub.2) and Argon (Ar).
10. The method of claim 1, wherein the performing the silicon precursor deposition step and the performing the metal precursor deposition step are repeated until the transition metal silicate film reaches a desired thickness.
11. The method of claim 1, wherein the method is performed using an atomic layer deposition (ALD) process.
12. The method of claim 1, wherein the transition metal silicate film comprises one of: a lanthanum silicate, a yttrium silicate, a magnesium silicate, an erbium silicate, or another rare earth metal silicate.
13. The method of claim 1, wherein the transition metal silicate film formed comprises less than about 20 at-% of hydrogen impurities, less than about 15 at-% of hydrogen impurities, less than about 10 at-% of hydrogen impurities, or less than about 5 at-% of hydrogen impurities.
14. The method of claim 1, wherein the transition metal silicate film formed comprises less than about 10 at-% of carbon impurities, less than about 5 at-% of carbon impurities, less than about 2 at-% of carbon impurities, or less than about 1 at-% of carbon impurities.
15. The method of claim 1, wherein the transition metal silicate film formed comprises less than about 10 at-% of nitrogen impurities, less than about 5 at-% of nitrogen impurities, less than about 2 at-% of nitrogen impurities, or less than about 1 at-% of nitrogen impurities.
16. The method of claim 5, wherein the metal precursor comprises an amidinate precursor.
17. The method of claim 1, wherein the transition metal silicate film is formed at a reaction temperature from 100-450 C., from 150-400 C., from 175-350 C., or from 200-300 C.
18. The method of claim 1, wherein an extent of silicon integration into the transition metal silicate film is dependent on a ratio of X to Y.
19. The method of claim 1, wherein the substrate comprises at least one of: a silicon substrate, a silicon-capped germanium substrate, a Ge substrate, a SiGe substrate, or a III-V semiconductor substrate.
20. A method of forming a transition metal silicate film comprising: providing a substrate for processing in a reaction chamber; performing a silicon precursor deposition onto the substrate, the performing the silicon precursor deposition comprising: pulsing a silicon precursor; purging the silicon precursor from the reaction chamber with a purge gas; pulsing an oxidizing precursor; and purging the oxidizing precursor from the reaction chamber with the purge gas; performing a metal precursor deposition onto the substrate, the performing the metal precursor deposition comprising: pulsing a metal precursor; purging the metal precursor from the reaction chamber with a purge gas; pulsing an oxidizing precursor; and purging the oxidizing precursor from the reaction chamber with the purge gas; wherein the silicon precursor deposition step is repeated X times; wherein the metal precursor deposition step is repeated Y times; and wherein a transition metal silicate film is formed; wherein the metal precursor comprises a metal atom bonded to a nitrogen atom or a carbon atom.
21. The method of claim 20, wherein the silicon precursor comprises at least one of: a silicon halide, such as silicon tetrachloride (SiCl.sub.4), trichloro-silane (SiCl.sub.3H), dichloro-silane (SiCl.sub.2H.sub.2), monochloro-silane (SiClH.sub.3), hexachlorodisilane (HCDS), octachlorotrisilane (OCTS), silicon iodides, or silicon bromides; an amino-based precursor, such as Hexakis(ethylamino)disilane (AHEAD) and SiH[N(CH.sub.3).sub.2].sub.3(3DMASi); a Bis(dialkylamino)silane, such as BDEAS (bis(diethylamino)silane); a mono(alkylamino)silane, such as di-isopropylaminosilane; or an oxysilane based precursor, such as tetraethoxysilane Si(OC.sub.2H.sub.5).sub.4.
22. The method of claim 20, wherein the metal precursor comprises at least one of: lanthanum; yttrium; an amidinate-based precursor, such as Lanthanum formamidinate (La(FAMD).sub.3), tris(N,N-diisopropylacetamidinato)lanthanum (La(iPrAMD).sub.3), or Tris(N,N-diisopropylacetamidinato) Yttrium (TDIPAY); a Cp(cyclopentadienyl)-based precursor, such as Tris(isopropyl-cyclopentadienyl) lanthanum (La(iPrCp).sub.3), Y(EtCp).sub.3, or tris(methylcyclopentadienyl)yttrium (Y(MeCp).sub.3); an amido-based chemistry, such as tris(bistrimethylsilylamido)-lanthanum (La[N(SiMe.sub.3).sub.2].sub.3); a diketonate based precursor, such as (La(THD).sub.3), (Y(THD).sub.3), or tris(2,2,6,6-tetramethyl-3,5-octanedionato)Yttrium (Y(tmod).sub.3); or an amide-based precursor, such as Tris[N,N-bis(trimethylsilyl)amide]yttrium.
23. The method of claim 20, wherein the oxidizing precursor comprises at least one of: water (H.sub.2O); hydrogen peroxide (H.sub.2O.sub.2); oxygen (O.sub.2); ozone (O.sub.3); oxygen plasma; atomic oxygen (O); oxygen radicals; or methyl alcohol (CH.sub.3OH).
24. The method of claim 20, wherein the transition metal silicate film is formed at a reaction temperature from about 100-450 C., or from 150-400 C., or from 175-350 C., or from 200-300 C.
25. The method of claim 20, wherein an extent of silicon integration into the transition metal silicate film is dependent on a ratio of X to Y, the ratio being approximately 5:1, approximately 10:1, approximately 15:1, or approximately 20:1.
26. The method of claim 20, wherein the method is performed using an atomic layer deposition (ALD) process.
27. The method of claim 20, wherein the purge gas comprises at least one of: nitrogen (N.sub.2) and Argon (Ar).
28. The method of claim 20, wherein the transition metal silicate film comprises one of: a lanthanum silicate, a yttrium silicate, a magnesium silicate, an erbium silicate, or another rare earth metal silicate.
29. The method of claim 20, wherein the substrate comprises at least one of: a silicon substrate, a silicon-capped germanium substrate, a Ge substrate, a SiGe substrate, or a III-V semiconductor substrate.
30. A reaction chamber, wherein the reaction chamber is configured to perform the method of claim 20.
Description
BRIEF DESCRIPTION OF THE DRAWING FIGURES
[0012] These and other features, aspects, and advantages of the invention disclosed herein are described below with reference to the drawings of certain embodiments, which are intended to illustrate and not to limit the invention.
[0013]
[0014]
[0015]
[0016]
[0017]
[0018]
[0019]
[0020] It will be appreciated that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help improve understanding of illustrated embodiments of the present disclosure.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0021] Although certain embodiments and examples are disclosed below, it will be understood by those in the art that the invention extends beyond the specifically disclosed embodiments and/or uses of the invention and obvious modifications and equivalents thereof. Thus, it is intended that the scope of the invention disclosed should not be limited by the particular disclosed embodiments described below.
[0022]
[0023] In at least one embodiment of the invention, the order of the subcycles may be varied such that an order of the subcycles could be in a sandwich structure. For example, if pulse ratio of the silicon oxide subcycle to the lanthanum oxide subcycle equals 2:1; then precursor deposition may proceed as one silicon oxide subcycle 100, followed by a lanthanum oxide subcycle 200, and then a silicon oxide subcycle 100. In another embodiment of the invention, the order of the subcycles could be such that either subcycle could be first or last. Subcycles may be inserted at non-fixed ratios in order to effectively grade a composition of the film versus a vertical distance from the substrate.
[0024] It may also be possible that different orders for subcycles result in a film with the similar properties.
[0025]
[0026] In other embodiments consistent with the invention, the oxygen precursor pulse/purge 120 may involve a pulse and purge of at least one of: water (H.sub.2O); diatomic oxygen (O.sub.2); hydrogen peroxide (H.sub.2O.sub.2); ozone (O.sub.3); oxygen plasma; atomic oxygen (O); oxygen radicals; or methyl alcohol (CH.sub.3OH). It may be possible that different oxidizing precursors could be used for the different cycles; for example, O.sub.3 may be used for the silicon oxide subcycle, while water can be used for the lanthanum oxide subcycle. In other embodiments of the invention, it may be possible to use an oxygen source that does not comprise ozone, O.sub.2, H.sub.2O.sub.2, H.sub.2O, methyl alcohol, or oxygen plasma.
[0027]
[0028] In at least one embodiment of the invention, a metal precursor in the metal precursor pulse/purge 210 may be one of the following: an amidinate based precursor, such as Lanthanum formamidinate (La(FAMD).sub.3) or tris(N,N-diisopropylacetamidinato)lanthanum (La(iPrAMD).sub.3); a diketonate precursor, such as (La(THD).sub.3); a Cp(cyclopentadienyl)-based precursor such as Tris(isopropyl-cyclopentadienyl)lanthanum (La(iPrCp).sub.3); or an amido-based chemistry such as tris(bistrimethylsilylamido)-lanthanum (La[N(SiMe.sub.3).sub.2].sub.3); or hybrid combinations of the above. In other embodiments consistent with the invention, the metal precursor may be a lanthanum or other rare earth metal precursor having a bond between nitrogen, such as a lanthanum amidinate, for example. The amidinate compounds may comprise delocalized electrons that result in the bond between the nitrogen and the lanthanum or rare earth metal. In other embodiments consistent with the invention, the metal precursor may be a lanthanum or other rare earth metal precursor having a bond with carbon, such as a lanthanum cyclopentadienyl, for example. This metal precursor may comprise delocalized electrons, which are considered to be compounds, in which the bond between the carbon and the lanthanum or rare earth forms. In other embodiments consistent with the invention, the metal precursor may be a lanthanum or other rare earth metal precursor having a bond with both nitrogen and carbon, such as a lanthanum amidinate and a lanthanum cyclopentadienyl compound, for example.
[0029] In other embodiments consistent with the invention, the oxygen precursor pulse/purge 220 may involve at least one of: water (H.sub.2O), diatomic oxygen (O.sub.2), hydrogen peroxide (H.sub.2O.sub.2), ozone (O.sub.3), oxygen plasma, oxygen radicals, atomic oxygen, or methyl alcohol (CH.sub.3OH). The metal oxide subcycle 200 may be substituted with an yttrium oxide subcycle or another element's subcycle depending on what is the final desired product. Other elements could be lanthanides, erbium, erbium oxide, magnesium, magnesium oxide, scandium, or scandium oxide, among others. These other materials may also be preferable as they demonstrate an ability to cause the V.sub.t shift. For yttrium, the yttrium subcycle may comprise a yttrium pulse, a purge of the yttrium precursor, a H.sub.2O pulse, and a purge of the H.sub.2O precursor. The yttrium precursor could be one of the following: a Cp(cyclopentadienyl)-based chemistry, such as Y(EtCp).sub.3 and tris(methylcyclopentadienyl)yttrium (Y(MeCp).sub.3); an amidinate-based precursor, such as Tris(N,N-diisopropylacetamidinato) Yttrium (TDIPAY); a diketonate precursor, such as (Y(THD).sub.3) and tris(2,2,6,6-tetramethyl-3,5-octanedionato)Yttrium (Y(tmod).sub.3); or an amide-based precursor, such as Tris[N,N-bis(trimethylsilyl)amide]yttrium. Typical temperatures for this process range from 100-450 C., or from 150-400 C., or from 175-350 C., or from 200-300 C., with pressures ranging from 1 to 10 Torr.
[0030] The pulse ratio X:Y of the silicon and metal oxide subcycles can allow for incorporation of Silicon (Si) into the metal silicate film. The pulse ratio X:Y may range to be 5:1, 7:1, 10:1, and 20:1.
[0031] An additional benefit attained through at least one embodiment of the invention includes a lower carbon impurity level. Carbon is considered as a trap center and may degrade the performance of a device formed using the deposited film. As a result, a lower carbon level may be preferable.
[0032] Carbon may be formed easily if strong oxygen reactants, such as ozone or oxygen plasmas, are used. These strong reactants may result in greater oxidation of the substrate. Conventional LaOx films deposited through ALD indicate a high carbon impurity level between 15-20%. In addition, conventional LaOx films may also show high hydroxide impurities as well as low silicon incorporation.
[0033] In accordance with at least one embodiment of the invention, a combination of a silicon halide precursor, a rare earth precursor having a bond with a nitrogen/carbon atom, a proper oxygen precursor (such as water), and a high mobility channel material may be the reason for a lower carbon impurity level. The proper oxygen precursor may result in less oxidation of the substrate, potentially providing for a good surface or interface for subsequent deposition of additional materials, such as a high-k material formed by ALD.
[0034] As shown in
[0035] In accordance with at least one embodiment of the invention, a lanthanum hydroxide film (La(OH).sub.3) may be formed. In at least one embodiment of the invention, for a pure lanthanum hydroxide (La(OH).sub.3) film, the hydrogen content could be less than 43%. In accordance with at least one embodiment of the invention, a lanthanum hydroxide film may have hydrogen impurities, ranging from less than 20 mol-% of hydroxide (OH), less than 15 mol-% of hydroxide (OH), less than 10 mol-% of hydroxide (OH), or less than 5 mol-% of hydroxide (OH).
[0036]
[0037] The particular implementations shown and described are illustrative of the invention and its best mode and are not intended to otherwise limit the scope of the aspects and implementations in any way. Indeed, for the sake of brevity, conventional manufacturing, connection, preparation, and other functional aspects of the system may not be described in detail. Furthermore, the connecting lines shown in the various figures are intended to represent exemplary functional relationships and/or physical couplings between the various elements. Many alternative or additional functional relationship or physical connections may be present in the practical system, and/or may be absent in some embodiments.
[0038] It is to be understood that the configurations and/or approaches described herein are exemplary in nature, and that these specific embodiments or examples are not to be considered in a limiting sense, because numerous variations are possible. The specific routines or methods described herein may represent one or more of any number of processing strategies. Thus, the various acts illustrated may be performed in the sequence illustrated, in other sequences, or omitted in some cases.
[0039] The subject matter of the present disclosure includes all novel and nonobvious combinations and subcombinations of the various processes, systems, and configurations, and other features, functions, acts, and/or properties disclosed herein, as well as any and all equivalents thereof.