An asymmetric metallocene scandium complex precursor, a preparation method and application thereof
By preparing asymmetric cyclopentadienylscandium complex precursors, the problems of low thermal stability and low deposition efficiency of homogeneous cyclopentadienylscandium in the ALD process were solved, achieving high reactivity and low-temperature stable deposition. It is highly adaptable and suitable for the ALD process of Sc2O3 thin films.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SUZHOU ORIGIN DEPOSITION MATERIALS CO LTD
- Filing Date
- 2026-02-24
- Publication Date
- 2026-06-12
AI Technical Summary
Existing homogeneous scandium precursors suffer from high thermal stability and incomplete ligand elimination, which affects film purity and deposition efficiency, making it difficult to achieve efficient, low-temperature stable deposition in ALD processes.
Asymmetric cyclopentadienylscandium complex precursors were synthesized by reacting anhydrous trivalent scandium halides with cyclopentadienyl salts of three different substituent groups to prepare heterogeneous ligand cyclopentadienylmethylcyclopentadienylethylcyclopentadienylscandium compounds, which were then used as precursors for Sc2O3 thin films in the ALD process.
It improves the reactivity of the ALD process, reduces energy consumption, minimizes thermal damage to the substrate material, increases deposition efficiency, and enables stable deposition at lower temperatures, adapting to a wider range of process conditions and avoiding precursor decomposition or incomplete reaction.
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Figure CN122187883A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of organic chemistry, and in particular to an asymmetric cyclopentadienyl scandium complex precursor, its preparation method, and its application. Background Technology
[0002] Scandium cyclohexene precursors, as rare-earth electronic chemicals, can be used for ALD deposition of pure scandium films or scandium-based alloys (such as scandium-aluminum and scandium-titanium alloys), which have important applications in aerospace, high-temperature coatings, and other fields. Scandium cyclohexene precursors can achieve stable deposition at 150-300℃, reducing energy consumption by more than 40% compared to traditional metal-organic precursors (requiring 350-450℃), while avoiding substrate deformation or material decomposition caused by high temperatures. Furthermore, the advantages of scandium cyclohexene in ALD applications are concentrated in three core areas: high dielectric constant film deposition, conformal coating of complex structures, and low-temperature process compatibility. Its technical characteristics are highly compatible with the atomic-level precision control requirements of ALD. Currently reported scandium cyclohexenes are all homogeneous ligand scandium cyclohexenes, but homogeneous ligand scandium cyclohexenes suffer from drawbacks such as high thermal stability, incomplete ligand elimination affecting film purity, and low deposition efficiency. Summary of the Invention
[0003] To address the aforementioned technical problems, this invention provides an asymmetric cyclopentadienylscandium complex precursor, its preparation method, and its applications. This invention is the first to synthesize a novel compound, cyclopentadienylmethylcyclopentadienylethylcyclopentadienylscandium, which is the first heterogeneous trisubstituted cyclopentadienylscandium ligand. This novel compound, as a precursor source material used in the preparation of Sc2O3 thin films by atomic layer deposition (ALD), shows great promise in the semiconductor and scientific research fields.
[0004] This invention is achieved through the following technical solution:
[0005] The first objective of this invention is to provide an asymmetric cyclopentadienyl scandium complex precursor, wherein the molecular formula of the asymmetric cyclopentadienyl scandium complex precursor is Sc(Cp1Cp2Cp3); wherein Cp1, Cp2 and Cp3 are each independently substituted or unsubstituted cyclopentadienyl ligands, and the molecular structures of the three are different from each other.
[0006] The structures of the asymmetric cyclopentadienyl scandium complex precursor, Cp1, Cp2, and Cp3 are shown below:
[0007] , , and ;
[0008] Among them, R1~R 15 Alkyl groups or H atoms selected independently from 1 to 5 carbon atoms. The alkyl groups include, but are not limited to, Me, Et, n-Pr, iPr, etc.
[0009] In one embodiment of the present invention, R in the asymmetric cyclopentadienyl scandium complex precursor 10 For methyl, R 11 It is ethyl, R1~R9 and R 12 ~R 15 Each is independent and represented by H.
[0010] The second objective of this invention is to provide a method for preparing the aforementioned asymmetric cyclopentadienyl scandium complex precursor, the preparation method comprising method one and method two:
[0011] The first method includes the following steps:
[0012] S1. Under a protective atmosphere, anhydrous trivalent scandium halide is heated and reacted with the first cyclopentadienyl salt and the second cyclopentadienyl salt in an organic solvent. The mixture is then filtered, the solvent is removed under reduced pressure, and the solid substance is obtained by sublimation.
[0013] S2. The solid substance obtained in step S1 is reacted with the third cyclopentadiene salt in an organic solvent, filtered, the solvent is removed under reduced pressure, and the substance is sublimed to obtain the asymmetric cyclopentadiene scandium complex precursor.
[0014] The second method includes the following steps:
[0015] S3. Under a protective atmosphere, anhydrous trivalent scandium halide is reacted with the first cyclopentadiene salt, the second cyclopentadiene salt and the third cyclopentadiene salt in an organic solvent by heating. After filtration, washing, removing the solvent under reduced pressure, and sublimation, the asymmetric cyclopentadiene scandium complex precursor is obtained.
[0016] The first cyclopentadiene salt is Cp1Na;
[0017] The second cyclopentadiene salt is MeCp2Na;
[0018] The third cyclopentadiene salt is EtCp3Na.
[0019] In one embodiment of the present invention, the trivalent scandium halide is selected from ScCl3, ScBr3 or ScI3.
[0020] In one embodiment of the present invention, in step S1, the heating temperature is 110℃-120℃ and the heating time is 4h-6h.
[0021] In one embodiment of the present invention, in step S2, the sublimation temperature is 160°C-170°C.
[0022] In one embodiment of the present invention, the mass ratio of the anhydrous trivalent scandium halide, the first cyclopentadiene salt, the second cyclopentadiene salt, and the third cyclopentadiene salt is 1:1-1.05:1-1.05:1-1.05.
[0023] In one embodiment of the present invention, in step S3, the heating temperature is 110℃-120℃ and the heating time is 4h-6h;
[0024] And / or, the sublimation temperature is 160℃-170℃.
[0025] In one embodiment of the present invention, the organic solvent is one or more of toluene, n-hexane, tetrahydrofuran, pyridine, diethyl ether, 2-methyltetrahydrofuran, acetonitrile, dichloromethane, and 1,4-dioxane.
[0026] A third objective of this invention is to provide the application of the aforementioned asymmetric scandium cyclopentadienyl complex precursor in atomic layer deposition processes.
[0027] This invention discloses for the first time a novel compound, cyclopentadienylmethylcyclopentadienylethylcyclopentadienylscandium; this invention also discloses two methods for preparing heterogeneous substituted triconecroleinium compounds. Method 1: Anhydrous trivalent scandium halide is reacted with two of three substituted alkyl salts in sequence, purified, and then the last alkyl salt is added to obtain the heterogeneous substituted triconecroleinium compound; Method 2: Anhydrous trivalent scandium halide is reacted with a mixture of three substituted alkyl salts to obtain the heterogeneous substituted triconecroleinium compound.
[0028] The general chemical formula for the reaction is:
[0029]
[0030] In one embodiment of the present invention, the target compound is attached to a characteristic group, wherein the one disclosed in this invention is R. 10 For Me, R 11 For Et, R1~R9 and R 12 ~R 15 H represents other compounds with similar structures obtained according to the preparation process of this invention, namely R1~R2. 15 Alkyl groups or H with 0 to 5 carbon atoms are all within the scope of protection of this invention, such as methylcyclopentadienylethylcyclopentadienylisopropylcyclopentadienyl scandium, cyclopentadienylmethylcyclopentadienylisopropylcyclopentadienyl scandium, cyclopentadienylmethylcyclopentadienylpentamethylcyclopentadienyl scandium, etc., are all within the scope of protection of this invention;
[0031] Compared with the prior art, the above-described technical solution of the present invention has the following advantages:
[0032] (1) This invention discloses for the first time an asymmetric cyclopentadienyl scandium complex precursor and its preparation method and application, specifically a compound of cyclopentadienylmethylcyclopentadienylethylcyclopentadienyl scandium;
[0033] (2) This invention breaks the limitation of traditional methods that can only prepare homogeneous ligand cyclopentadienyl scandium-related compounds, that is, under the premise that the metal core is scandium, different types of cyclopentadienyl groups can be connected at the same time;
[0034] (3) Compared to homogeneous scandium cyclopentadienylscandium, heterogeneous scandium cyclopentadienylscandium exhibits high reactivity in the ALD process, enabling stable deposition at lower temperatures. This high reactivity stems from the chemically active nature of scandium and the potential increase in surface active sites due to its heterogeneous structure. In the ALD process, high reactivity helps reduce energy consumption, minimize thermal damage to the substrate material, and improve deposition efficiency;
[0035] (4) Non-homogeneous ligands can balance volatility and reactivity, adapt to a wider range of process conditions, and do not require strict temperature control to avoid precursor decomposition or incomplete reaction.
[0036] (5) Compared with the symmetrical structure of symmetrical cyclopentadienyl groups, the asymmetric structure of the asymmetric cyclopentadienyl scandium complex precursor of the present invention has weaker intermolecular forces, lower boiling point, and is more conducive to the use in the coating process; moreover, scandium metal itself has a small atomic radius, strong dielectric properties after doping, and is not easy to form an unstable transition phase with the substrate; the asymmetric cyclopentadienyl structure makes the product have a low boiling point, more controllable volatility and reactivity, and less prone to condensation and tube blockage. Attached Figure Description
[0037] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.
[0038] Figure 1 This is a flowchart of the synthesis process in Embodiment 1 of the present invention;
[0039] Figure 2 This is the NMR spectrum of the product in Example 1 of the present invention;
[0040] Figure 3 This is a flowchart of the synthesis process in Embodiment 2 of the present invention;
[0041] Figure 4 This is a growth diagram of Sc2O3 thin films prepared from the asymmetric scandium cyclopentadienyl complex precursor of the present invention at different temperatures. Detailed Implementation
[0042] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.
[0043] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, and the materials and reagents used are commercially available.
[0044] Example 1
[0045] This embodiment provides a method for preparing an asymmetric cyclopentadienyl scandium complex precursor (flowchart shown below). Figure 1 As shown), the details are as follows:
[0046] Under nitrogen protection, anhydrous scandium trichloride (0.1 mol, 15.132 g) was added to a 250 mL reaction flask. Cyclopentadienyl sodium (0.105 mol, 9.2484 g) and methylcyclopentadienyl sodium (0.105 mol, 10.7184 g) were dissolved in 150 mL of toluene and transferred to reaction flask. The mixture was heated and stirred at 110 °C for 4 h. The filtrate was then collected by filtration, and the solvent was removed under reduced pressure. The product was sublimated at 160 °C. Ethylcyclopentadienyl sodium (0.105 mol, 12.1947 g) dissolved in 100 mL of toluene was added. The mixture was heated and stirred at 110 °C for 4 h. The filtrate was then collected by filtration, and the solvent was removed under reduced pressure. The target product was sublimated at 170 °C. The product was a red solid (0.072 mol, 20.33 g) at room temperature, with a yield of 72%.
[0047] The NMR data are as follows: 1 H NMR (400 MHz, C6D6): δ (ppm) = 0.96 (t, 3H, CH2CH3),1.88 (t, 3H, CCH3), 2.24-2.26 (q, 2H, CCH2CH3), 5.91(m, 4H, CHCHCH), 6.02 (m,4H, CHCHCH), 6.10 (m, 4H, CHCHCH). like Figure 2 As shown, the splitting of the NMR spectrum of the product due to the special characteristic of structural asymmetry is a normal phenomenon.
[0048] Metal purity: 5N.
[0049] Example 2
[0050] This embodiment provides a method for preparing an asymmetric cyclopentadienyl scandium complex precursor (flowchart shown below). Figure 3 As shown), the details are as follows:
[0051] Under nitrogen protection, anhydrous scandium trichloride (0.1 mol, 15.132 g) was added to a 250 mL reaction flask 1. Sodium cyclopentadienyl (0.1 mol, 8.808 g), sodium methylcyclopentadienyl (0.1 mol, 10.208 g), and sodium ethylcyclopentadienyl (0.1 mol, 11.614 g) were dissolved in 200 mL of toluene and transferred to reaction flask 1. The mixture was heated and stirred at 110 °C for 8 h. The filtrate was then collected by filtration, and the solvent was removed under reduced pressure. The target product was sublimated at 170 °C and was a red solid (0.059 mol, 16.657 g) at room temperature, with a yield of 59%.
[0052] Example 3
[0053] Under nitrogen protection, anhydrous scandium tribromide (0.1 mol, 28.467 g) was added to a 250 mL reaction flask. Cyclopentadienyl sodium (0.105 mol, 9.2484 g) and methylcyclopentadienyl sodium (0.105 mol, 10.7184 g) were dissolved in 150 mL of toluene and transferred to the reaction flask. The mixture was heated and stirred at 110 °C for 4 h. The filtrate was then collected by filtration, and the solvent was removed under reduced pressure. The product was sublimated at 160 °C. Ethylcyclopentadienyl sodium (0.105 mol, 12.1947 g) dissolved in 100 mL of toluene was added. The mixture was heated and stirred at 110 °C for 4 h. The filtrate was then collected by filtration, and the solvent was removed under reduced pressure. The target product was sublimated at 170 °C. The product was a red solid (0.07 mol, 19.76 g) at room temperature, with a yield of 70%.
[0054] Comparative Example 1
[0055] Under nitrogen protection, anhydrous scandium trichloride (0.1 mol, 15.132 g) was added to a 250 mL reaction flask 1. Cyclopentadienyllithium (0.105 mol, 7.56 g) and methylcyclopentadienyllithium (0.105 mol, 9.04 g) were dissolved in 150 mL of toluene and transferred to reaction flask 1. The mixture was heated and stirred at 110 °C for 4 h. The filtrate was then collected by filtration, and the solvent was removed under reduced pressure. The product was sublimated at 160 °C. Ethylcyclopentadienyllithium (0.105 mol, 10.51 g) dissolved in 100 mL of toluene was added. The mixture was heated and stirred at 110 °C for 4 h. The filtrate was then collected by filtration, and the solvent was removed under reduced pressure. The target product was sublimated at 170 °C. The product was a red solid (0.043 mol, 12.14 g) at room temperature, with a yield of 43%. The lithium content in the metal was 8600 ppb, indicating a low metal purity.
[0056] Comparative Example 2
[0057] Under nitrogen protection, anhydrous scandium trichloride (0.1 mol, 15.132 g) was added to a 250 mL reaction flask 1. Cyclopentadienyl sodium (0.12 mol, 10.57 g) and methylcyclopentadienyl sodium (0.12 mol, 12.25 g) were dissolved in 150 mL of toluene and transferred to reaction flask 1. The mixture was heated and stirred at 110 °C for 4 h. The filtrate was then collected by filtration, and the solvent was removed under reduced pressure. The product was sublimated at 160 °C. Ethylcyclopentadienyl sodium (0.12 mol, 13.94 g) dissolved in 100 mL of toluene was added. The mixture was heated and stirred at 110 °C for 4 h. The filtrate was then collected by filtration, and the solvent was removed under reduced pressure. The target product was sublimated at 170 °C. The product was a red solid (0.023 mol, 6.49 g) at room temperature, with a yield of 23%.
[0058] Application test cases
[0059] Using the Sc(CpMeCpEtCp) obtained in Example 1 as the Sc precursor, O3 as the co-reactant gas, and a Si wafer as the substrate, with a deposition cycle of 300 cycles, Sc2O3 thin films can be grown at 300-400°C. (See [link to documentation]). Figure 4 It can be seen that the asymmetric scandium cyclopentadienyl complex precursor of this application can be used for the growth of Sc2O3 thin films, and the film thickness increases significantly with increasing process temperature.
[0060] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.
Claims
1. An asymmetric cyclopentadienyl scandium complex precursor, characterized in that, The molecular formula of the asymmetric scandium cyclopentadienyl complex precursor is Sc(Cp1Cp2Cp3); wherein Cp1, Cp2 and Cp3 are each independently substituted or unsubstituted cyclopentadienyl ligands, and the molecular structures of the three are different from each other. The structures of the asymmetric cyclopentadienyl scandium complex precursor, Cp1, Cp2, and Cp3 are shown below: , , and ; Among them, R1~R 15 Alkyl groups or H atoms selected independently of 1 to 5 carbon atoms.
2. The asymmetric cyclopentadienyl scandium complex precursor according to claim 1, characterized in that, R in the asymmetric scandium cyclopentadiene complex precursor 10 For methyl, R 11 It is ethyl, R1~R9 and R 12 ~R 15 Each is independent and represented by H.
3. The method for preparing the asymmetric cyclopentadienyl scandium complex precursor according to claim 1 or 2, characterized in that, The preparation method includes Method 1 and Method 2: The first method includes the following steps: S1. Under a protective atmosphere, anhydrous trivalent scandium halide is heated and reacted with the first cyclopentadienyl salt and the second cyclopentadienyl salt in an organic solvent. The mixture is then filtered, the solvent is removed under reduced pressure, and the solid substance is obtained by sublimation. S2. The solid substance obtained in step S1 is reacted with the third cyclopentadiene salt in an organic solvent, filtered, the solvent is removed under reduced pressure, and the substance is sublimed to obtain the asymmetric cyclopentadiene scandium complex precursor. The second method includes the following steps: S3. Under a protective atmosphere, anhydrous trivalent scandium halide is reacted with the first cyclopentadiene salt, the second cyclopentadiene salt and the third cyclopentadiene salt in an organic solvent by heating. After filtration, washing, removing the solvent under reduced pressure, and sublimation, the asymmetric cyclopentadiene scandium complex precursor is obtained. The first cyclopentadiene salt is Cp1Na; The second cyclopentadiene salt is MeCp2Na; The third cyclopentadiene salt is EtCp3Na.
4. The preparation method according to claim 3, characterized in that, The trivalent scandium halide is selected from ScCl3, ScBr3, or ScI3.
5. The preparation method according to claim 1, characterized in that, In step S1, the heating temperature is 110℃-120℃ and the heating time is 4h-6h.
6. The preparation method according to claim 1, characterized in that, In step S2, the sublimation temperature is 160℃-170℃.
7. The preparation method according to claim 1, characterized in that, The mass ratio of the anhydrous trivalent scandium halide, the first cyclopentadiene salt, the second cyclopentadiene salt, and the third cyclopentadiene salt is 1:1-1.05:1-1.05:1-1.
05.
8. The preparation method according to claim 1, characterized in that, In step S3, the heating temperature is 110℃-120℃, and the heating time is 4h-6h; And / or, the sublimation temperature is 160℃-170℃.
9. The preparation method according to claim 1, characterized in that, The organic solvent is one or more of toluene, n-hexane, tetrahydrofuran, pyridine, diethyl ether, 2-methyltetrahydrofuran, acetonitrile, dichloromethane, and 1,4-dioxane.
10. The application of the asymmetric scandium cyclopentadienyl complex precursor according to claim 1 or 2 in atomic layer deposition process.