Niobium precursor compound for thin film deposition and method for forming niobium-containing thin film using same

Abstract

According to embodiments of the present invention, the niobium precursor compound is represented by the following chemical formula 1 or chemical formula 2: Therefore, the niobium precursor compound according to embodiments of the present invention exhibits excellent thermal stability, exists in a liquid state at room temperature, and has high volatility, thereby having the advantage of being suitable for use in thin film formation processes. Furthermore, niobium thin films formed using the niobium precursor compound according to embodiments of the present invention have low residue content and uniform physical properties.

Description

[Technical Field]

[0001] The present invention relates to a niobium precursor compound and a method for forming a niobium-containing thin film using the compound, and more particularly to a heterojunction niobium compound used as a precursor for thin film deposition and a method for forming a niobium-containing thin film using the heterojunction niobium compound. [Previous Technology]

[0002] With the development of electronic technology, the demand for miniaturization and weight reduction of electronic devices used in various electronic devices is rapidly increasing. In order to form sophisticated electronic devices, various physical and chemical deposition methods have been proposed, and various studies are being conducted on the fabrication of various electronic devices such as metal thin films, metal oxide thin films, or metal nitride thin films through these deposition methods.

[0003] In the manufacture of semiconductor devices, metal-organic chemical vapor deposition (MOCVD) or atomic layer deposition (ALD) processes are typically used to form thin films containing group 5 metal compounds.

[0004] Because the ALD process undergoes a self-limiting reaction compared to the MOCVD process, it has excellent step coverage, and because it is a relatively low-temperature process, it has the advantage of avoiding the degradation of device performance caused by thermal diffusion.

[0005] To deposit niobium (Nb)-containing thin films in Group 5 metal compounds, selecting a precursor compound suitable for the deposition process is crucial. Currently, various types of niobium precursors exist in the semiconductor industry. Common niobium precursor compounds include niobium halides such as niobium chloride (V), niobium ethoxides such as niobium ethoxide (V), and similar compounds. These niobium precursor compounds are homogeneous precursor compounds composed of one or more identical ligands. In the case of niobium halides, they possess high thermal stability, a wide deposition temperature range, and sufficient reactivity, but due to their solid state at room temperature, they exhibit low vapor pressure. Furthermore, the byproducts generated during deposition affect the physical properties of the film, making it difficult to form films with uniform physical properties. In the case of niobium oxyoxides, due to their sufficient vapor pressure and low melting point, niobium oxyoxides are easily synthesized in the liquid phase, but due to their low thermal stability during film formation, they are prone to decomposition, resulting in a high carbon content in the film.

[0006] Therefore, heteroligand precursor compounds have recently been proposed to compensate for the shortcomings of homoligand precursor compounds. Heteroligand precursor compounds contain two or more different ligands. Typical examples of heteroligand precursor compounds may include alkylamide-amide-imino precursor compounds, such as tris(diethylamino)(tert-butylimino)niobium(V). Such alkylamide-amide-imino precursor compounds have the advantage of ensuring high growth per film cycle (GPC) over a wide temperature range, thus enabling the formation of high-quality films compared to homoligand precursor materials. However, a disadvantage is the high carbon content in the film at low temperatures.

[0007] Even when performing deposition processes under the same conditions, ligands with different chemical structures exhibit varying reactivity with the reactive gases, resulting in different deposition surfaces. In particular, the charge trapping density can be affected by the number of ligands in the precursor compound that react with the hydroxyl-terminated surface during the ALD process, and this can influence film quality. Therefore, by controlling the number of reacting ligands in each cycle in a substantially uniform manner, an ideal film with a low charge trapping density can be obtained. However, known hybrid niobium precursor compounds present problems due to their rapid reactivity, high ligand exchangeability, and difficulty in controlling vapor pressure, thus limiting their ability to improve process efficiency. In particular, niobium precursor compounds should possess thermal stability during the MOCVD process so that they decompose on heated substrates but not during transport. Furthermore, while niobium precursor compounds are not thermally decomposed during the ALD process, they should possess high thermal stability and reactivity so that they can react with the corresponding reactants when exposed to them.

[0008] Therefore, there is still a need for a precursor compound that can form a high-quality uniform film by existing in a liquid state at room temperature and having excellent thermal stability and reactivity, so that it can be easily used in ALD and MOCVD processes. [Summary of the Invention]

[0009] One object of the present invention is to provide a niobium precursor compound that is suitable for thin film growth, has strong thermal stability, has high vapor pressure, and exists in a liquid state at room temperature, thereby solving the process problems caused by the use of conventional niobium precursor compounds.

[0010] Another object of the present invention is to provide a niobium precursor composition for thin film deposition, which is capable of providing high-quality uniform thin films using niobium precursor compounds.

[0011] Another object of the present invention is to provide a method for forming niobium-containing thin films, which, by using a niobium precursor composition for thin film deposition, can form high-quality thin films while having excellent processing efficiency.

[0012] The problems of the present invention are not limited to those described above, and other unmentioned problems will be clearly understood by those skilled in the art through the following description.

[0013] One embodiment of the present invention provides a niobium precursor compound represented by the following chemical formula 1 or chemical formula 2.

[0014] [Chemical Formula 1]

[0015] [Chemical Formula 2]

[0016] (In Formula 1, R1 and R2 are each independently selected from straight-chain alkyl groups having 1 to 6 carbon atoms and branched alkyl groups having 3 to 6 carbon atoms, and R3, R4 and R5 are each independently selected from hydrogen, straight-chain alkyl groups having 1 to 10 carbon atoms and branched alkyl groups having 3 to 10 carbon atoms; in Formula 2, R6 and R7 are each independently selected from straight-chain alkyl groups having 1 to 6 carbon atoms and branched alkyl groups having 3 to 6 carbon atoms; R8 and R9 are each independently selected from hydrogen, straight-chain alkyl groups having 1 to 10 carbon atoms and branched alkyl groups having 3 to 10 carbon atoms; R10 is selected from straight-chain alkylene groups having 1 to 20 carbon atoms and branched alkylene groups having 3 to 20 carbon atoms; and R11 and R12 are each independently selected from hydrogen and straight-chain alkyl groups having 1 to 4 carbon atoms; and in Formulas 1 and 2, n is an integer from 1 to 5).

[0017] Another embodiment of the present invention provides a precursor composition for depositing niobium-containing thin films, and the precursor composition for thin film deposition according to an embodiment of the present invention comprises the niobium precursor compound represented by the above-described chemical formula 1 or chemical formula 2.

[0018] Another embodiment of the present invention provides a method for forming a niobium-containing thin film, wherein the method uses the niobium precursor compound represented by the above-mentioned chemical formula 1 or chemical formula 2 to deposit a thin film on a substrate through a metal-organic chemical vapor deposition (MOCVD) process or an atomic layer deposition (ALD) process.

[0019] Specific details of other implementation schemes are included in the detailed description and figures.

[0020] The niobium precursor compound according to one embodiment of the present invention has excellent thermal stability, exists in a liquid state at room temperature, and has high volatility, thereby having the advantage of being suitable for use in thin film formation processes. In particular, the niobium precursor compound according to the present invention has excellent thermal stability and high reactivity, enabling the formation of high-quality niobium thin films when forming thin films through MOCVD or ALD processes.

[0021] Some ligands contained in the niobium precursor compound according to one embodiment of the present invention include sterically hindered substituents. Therefore, when preparing the niobium precursor compound, the purification of the product can be promoted, which helps to improve purity.

[0022] Furthermore, when using a niobium precursor compound according to an embodiment of the present invention for an ALD process, the quality of the film can be further improved by maintaining a constant growth per film cycle (GPC) over a wide temperature range.

[0023] Furthermore, niobium thin films formed from niobium precursor compounds according to an embodiment of the present invention can be used for various applications, such as dielectrics, barrier films, and electrodes, due to their excellent thermal stability, excellent morphological properties, low diffusivity, low leakage, and low charge trapping properties.

[0024] The effects of the present invention are not limited to the above-described examples, and the present invention includes a variety of other effects.

Implementation Method

[0026] The advantages and features of the present invention, as well as methods of implementing them, will become apparent from the examples described in detail below with reference to the accompanying drawings. However, the invention is not limited to the examples disclosed below, but will be practiced in various different forms. These examples are provided only to complete the disclosure of the invention and to fully inform those skilled in the art of the scope of the invention. The invention is limited only to the scope of the claims.

[0027] In describing the present invention, detailed descriptions of relevant known technologies will be omitted if it is determined that such detailed descriptions may unnecessarily obscure the gist of the invention. When terms such as "comprising," "having," or "constituting" are used in the present invention, other parts may be added unless "only" is used. When an ingredient is expressed in the singular, the plural is included unless otherwise expressly stated.

[0028] When interpreting components, even if there is no separate explicit description, it is interpreted as including the error range.

[0029] Throughout this specification, the term “room temperature” means a temperature of 15°C to 30°C, or 20°C to 27°C.

[0030] The niobium precursor compound according to one embodiment of the present invention can be represented by the following chemical formula 1.

[0031] [Chemical Formula 1]

[0032] In Formula 1, R1 and R2 may each be independently selected from any of the following: straight-chain alkyl groups having 1 to 6 carbon atoms and branched alkyl groups having 3 to 6 carbon atoms. For example, R1 may be a straight-chain alkyl group having 1 to 3 carbon atoms, and R2 may be a branched alkyl group having 3 to 6 carbon atoms, but is not limited thereto.

[0033] In Formula 1, R3, R4, and R5 may each be independently selected from any of the following: hydrogen, a straight-chain alkyl group having 1 to 10 carbon atoms, and a branched alkyl group having 3 to 10 carbon atoms. Specifically, for example, R3 and R4 may each be a straight-chain alkyl group having 1 to 6 carbon atoms, and R5 may be a branched alkyl group having 3 to 6 carbon atoms, but is not limited thereto.

[0034] In chemical formula 1, n is an integer from 1 to 5.

[0035] For example, in Formula 1, n can be 1, and R1 can be a straight-chain alkyl group having 1 to 6 carbon atoms. Preferably, for example, R1 in Formula 1 can be methyl. In the case of including such a methylcyclopentadiene structure, the binding force with the metal may be reduced compared to a cyclopentadiene structure without methyl. Therefore, the amount of unwanted residues in the film formed through the deposition process can be significantly reduced. Furthermore, in the case of including a methylcyclopentadiene structure, the synthesis of heterocyclopentadiene precursor compounds can be promoted due to the masking effect of methylcyclopentadiene. In addition, by improving the purification efficiency of niobium precursor compounds, heterocyclopentadiene precursor compounds with high purity can be obtained.

[0036] More specifically, the niobium precursor compound can be a compound represented by the following chemical formula 3.

[0037] [Chemical Formula 3]

[0038] Niobium precursor compounds with a structure such as Formula 3 exhibit superior thermal stability and can further reduce residue content during film formation. Furthermore, they demonstrate constant growth per cycle (GPC) over a wide temperature range in the deposition process and can be used in both ALD and MOCVD processes.

[0039] The niobium precursor compound according to another embodiment of the present invention can be represented by the following chemical formula 2.

[0040] [Chemical Formula 2]

[0041] The niobium precursor compound according to Formula 2 forms a stable structure, and the nitrogen atom of the ligand -OR10N(R11)(R12) bonded to the niobium atom forms a coordinate bond with the niobium atom. Therefore, the niobium precursor compound represented by Formula 2 has a more stable structure than the niobium precursor compound of Formula 1, thereby having the advantage of superior thermal stability. Therefore, the film formed by the deposition process using the niobium precursor compound represented by Formula 2 has a lower residue content and exhibits a constant growth per cycle (GPC) over a wider temperature range. Therefore, the film prepared using the niobium precursor compound represented by Formula 2 exhibits higher quality characteristics.

[0042] In Formula 2, R6 and R7 can each be independently selected from any of the following: straight-chain alkyl groups having 1 to 6 carbon atoms and branched alkyl groups having 3 to 6 carbon atoms. Specifically, for example, R6 can be a straight-chain alkyl group having 1 to 3 carbon atoms, and R7 can be a branched alkyl group having 3 to 6 carbon atoms, but is not limited thereto.

[0043] In chemical formula 2, R8 and R9 may each be independently selected from any of the following: hydrogen, straight-chain alkyl groups having 1 to 10 carbon atoms, and branched alkyl groups having 3 to 10 carbon atoms. Specifically, for example, R8 and R9 may each be straight-chain alkyl groups having 1 to 6 carbon atoms, but are not limited thereto.

[0044] In Formula 2, R10 may be selected from straight-chain alkylene groups having 1 to 20 carbon atoms and branched alkylene groups having 3 to 20 carbon atoms. Specifically, for example, R10 may be a straight-chain alkylene group having 1 to 6 carbon atoms, but is not limited thereto.

[0045] In Formula 2, R11 and R12 may each be independently selected from any of the following: hydrogen and straight-chain alkyl groups having 1 to 4 carbon atoms. Specifically, for example, R11 and R12 may each be a straight-chain alkyl group having 1 to 6 carbon atoms, but are not limited thereto.

[0046] In chemical formula 2, n is an integer from 1 to 5.

[0047] For example, in Formula 2, n can be 1, and R6 can be a straight-chain alkyl group having 1 to 6 carbon atoms. Preferably, for example, R6 in Formula 2 can be methyl. As described above, when a methylcyclopentadiene structure is included, the binding force with the metal is reduced compared to cyclopentadiene without a methyl group, thereby significantly reducing the amount of unwanted residue in the film. Furthermore, due to the masking effect of methylcyclopentadiene, the synthesis and purification of heterocyclic niobium precursor compounds are promoted, thereby obtaining niobium precursor compounds with high purity and high quality.

[0048] More specifically, the niobium precursor compound can be a compound represented by the following chemical formula 4.

[0049] [Chemical Formula 4]

[0050] The niobium precursor compound represented by Formula 4 can further improve thermal stability and further reduce the amount of residue during film formation. Therefore, the film prepared by the deposition process using the niobium precursor compound of Formula 4 has superior physical properties.

[0051] Niobium precursor compounds represented by chemical formula 1 or chemical formula 2 can be used as precursor compositions for depositing niobium-containing thin films.

[0052] Furthermore, since the niobium precursor compound according to an embodiment of the present invention is in a liquid state at room temperature, it is easy to store and handle, and has high volatility, thus it can be advantageously used to form thin films using deposition processes.

[0053] Hereinafter, a method for forming a niobium-containing thin film according to an embodiment of the present invention will be described in detail. The method for forming the niobium-containing thin film uses the above-described niobium precursor compound, and repeated descriptions of the niobium precursor compound are omitted.

[0054] In a method for forming a niobium-containing thin film according to an embodiment of the present invention, the thin film is deposited on a substrate by a deposition process using a niobium precursor compound represented by chemical formula 1 or chemical formula 2.

[0055] The deposition process may include atomic layer deposition (ALD) or chemical vapor deposition (CVD), such as metal-organic chemical vapor deposition (MOCVD). The deposition process can be performed at temperatures ranging from 50°C to 700°C.

[0056] First, the niobium precursor compound represented by chemical formula 1 or chemical formula 2 is transferred onto the substrate. For example, the niobium precursor compound may be supplied onto the substrate by means of methods such as bubbling, gas phase quality flow controller, direct gas injection (DGI), direct liquid injection (DLI), or liquid transfer by dissolving it in an organic solvent and transferring it, but is not limited thereto.

[0057] More specifically, the niobium precursor compound may be mixed with a carrier gas or dilution gas, which includes one or more of the group consisting of argon (Ar), nitrogen (N2), helium (He) and hydrogen (H2), and transferred to the substrate by bubbling or direct gas injection.

[0058] Meanwhile, the deposition process may include the step of supplying one or more reactive gases during the formation of the niobium thin film, the reactive gases being selected from the group consisting of water vapor (H2O), oxygen (O2), ozone (O3) and hydrogen peroxide (H2O2).

[0059] As another example, the deposition process may include the step of supplying one or more reactive gases during the formation of the niobium thin film, the reactive gases being selected from the group consisting of ammonia (NH3), hydrazine (N2H4), nitrous oxide (N2O) and nitrogen (N2).

[0060] Niobium films manufactured by the method for forming thin films according to an embodiment of the present invention can provide high-quality films by effectively reducing the amount of residue. Furthermore, the method for forming thin films according to an embodiment of the present invention can provide niobium films with more uniform physical properties by exhibiting a constant growth per film cycle (GPC) over a wider range of film growth temperature.

[0061] The niobium precursor compound according to the present invention will be described in more detail below through the following examples. However, this is only for the purpose of helping to understand the present invention, and the present invention is not limited to the following examples.

[0062] [Example 1]

[0063] 1. Preparation of intermediate compounds

[0064] 32.9 g (0.111 mol, 1 equivalent) of (tert-butylimino)tris(dimethylamino)niobium ((tBuN)(NMe2)3Nb) and 300 mL of n-hexane were injected into a flame-dried 500 mL Schlenk flask and stirred at room temperature. 11 g (0.137 mol, 1.2 equivalent) of methylcyclopentadiene (C5MeH5) was added dropwise to the flask at -20 °C or lower, and the reaction solution was stirred at room temperature for 12 hours. The solvent was then removed from the reaction solution under reduced pressure, and the solvent-removed reaction solution was distilled off under reduced pressure to give 26.5 g (72% yield) of a pale yellow liquid compound represented by (η-C5H4CH3)(tBuN)Nb(N(CH3)2)2.

[0065] The synthesis of the intermediate compound (η-C5H4CH3)(tBuN)Nb(N(CH3)2)2, represented by the following chemical formula A, was confirmed by nuclear magnetic resonance analysis (1H NMR).

[0066] [Chemical Formula A]

[0067] 2. Preparation of compound (η-C5H4CH3)(tBuN)Nb(N(CH3)2)(tBuO)

[0068] 26.5 g (0.08 mol, 1 equivalent) of the intermediate compound (tert-butylimino)bis(dimethylamino)(methylcyclopentadienyl)niobium(η-C5H4CH3)(tBuN)Nb(N(CH3)2)2 prepared as described above and 150 mL of n-hexane were injected into a flame-dried 500 mL Schlenk flask and stirred at room temperature. 6.5 g (0.088 mol, 1.1 equivalent) of tert-butanol (tBuOH) was added dropwise to the flask at -20°C or lower, and the reaction solution was stirred at room temperature for 12 hours. The solvent was then removed from the reaction solution under reduced pressure, and the solvent-removed reaction solution was distilled under reduced pressure to give 16.7 g (58% yield) of a pale yellow liquid compound.

[0069] The synthesis of the niobium precursor compound (η-C5H4CH3)(tBuN)Nb(N(CH3)2)(tBuO) represented by the following chemical formula 3 was confirmed by nuclear magnetic resonance analysis (1H NMR).

[0070] [Chemical Formula 3]

[0071] [Example 2]

[0072] 32.9 g (0.099 mol, 1 equivalent) of (tert-butylimino)bis(dimethylamino)(methylcyclopentadienyl)niobium(n-C5H4CH3)(tBuN)Nb(N(CH3)2)2 and 300 mL of n-hexane were injected into a flame-dried 500 mL Schlenk flask and stirred at room temperature. 17.7 g (0.199 mol, 2 equivalents) of dimethylethanolamine ((CH3)2NCH2CH2OH) was added dropwise to the flask at -20°C or lower, and the reaction solution was stirred at room temperature for 24 hours. The solvent was then removed from the reaction solution under reduced pressure, and the solvent-removed reaction solution was distilled under reduced pressure to give 15.7 g (yield 42%) of a pale yellow liquid compound.

[0073] The synthesis of the niobium precursor compound (η-C5H4CH3)(tBuN)Nb(N(CH3)2)((CH3)2NCH2CH2O) represented by the following chemical formula 4 was confirmed by nuclear magnetic resonance analysis (1H NMR).

[0074] [Chemical Formula 4]

[0075] [Comparative Example 1]

[0076] 11 g (0.029 mol, 1 equivalent) of bis(diethylamino)(tert-butylimino)(cyclopentadienyl)niobium(η-C5H5)(tBuN)Nb(NEt2)2 and 150 mL of n-hexane were injected into a flame-dried 500 mL Schlenk flask and stirred at room temperature. 3.8 g (0.063 mol, 2.2 equivalents) of isopropanol [C3H7OH] was added dropwise to the flask at -20 °C or lower, and the reaction solution was stirred at room temperature for 12 hours. The solvent was removed from the reaction solution under reduced pressure, and the solvent-removed reaction solution was distilled under reduced pressure to give 9 g (90% yield) of a pale yellow liquid compound.

[0077] The synthesis of the niobium precursor compound (η-C5H5)(tBuN)Nb(OCHC2H6)2, represented by the following chemical formula 5, was confirmed by nuclear magnetic resonance analysis (1H NMR).

[0078] [Chemical Formula 5]

[0079] [Experimental Example]

[0080] 1. Thermogravimetric analysis

[0081] To determine the thermal properties of the compounds according to Comparative Example 1 and Examples 1 and 2, respectively, thermogravimetric analysis (TGA) was performed. First, the thermogravimetric analyzer was stored in a nitrogen glove box, where the moisture and oxygen content were maintained below 1 ppm. After placing 15 mg of sample into the crucible, measurements were taken while the temperature was increased from 35°C to 350°C at a rate of 10°C / min. The mass loss of the sample as a function of crucible temperature was monitored. The results are shown in Figure 1.

[0082] Figure 1 is a graph showing the thermogravimetric analysis (TGA) results of each niobium precursor compound according to Comparative Example 1 and Examples 1 and 2.

[0083] Referring to Figure 1, it can be confirmed that the niobium precursor compounds prepared according to each of Examples 1 and 2 have a non-volatile residue content of less than 2% by weight at a temperature of 330°C or higher. Furthermore, it can be confirmed from the graph in Figure 1 that the niobium precursor compounds prepared according to each of Examples 1 and 2 do not decompose or form byproducts upon volatilization. That is, it can be seen that the niobium precursor compounds prepared according to Examples 1 and 2 exhibit thermal stability through volatilization with virtually no residue.

[0084] In contrast, in the case of the niobium precursor compound according to Comparative Example 1, a decrease in quality occurs at temperatures close to 100°C, which is much lower than in Examples 1 and 2, and the half-life is also lower compared to those examples. This confirms that the niobium precursor compound according to Comparative Example 1 has poorer thermal properties compared to those in the examples.

[0085] In summary, the niobium precursor compounds according to Examples 1 and 2 exist in a liquid state at room temperature for easy handling and purification, do not allow thermal decomposition during heating, and are converted into a vapor state through volatilization with almost no residue. Therefore, it can be seen that the niobium precursor compounds according to Examples 1 and 2 can be readily applied to MOCVD or ALD processes.

[0086] 2. Thin Film Deposition Characteristics

[0087] The growth per film cycle (GPC) during the atomic layer deposition process using the niobium precursor compounds according to Comparative Example 1, Example 1, and Example 2 was analyzed. The results are shown in Figure 2.

[0088] Figure 2 is a graph showing the growth per film cycle (GPC) based on the deposition temperature during the atomic layer deposition process using each niobium precursor compound according to Comparative Example 1, Example 1 and Example 2.

[0089] As deposition conditions, a niobium precursor compound was filled into a small container and then heated to 110°C, using ozone (O3) as an oxidant. A silicon wafer was used as the reaction substrate, and deposition was performed by heating the silicon wafer from 250°C to 340°C. After introducing a precursor pulse for 10 seconds, argon (Ar) was purged for 10 seconds. Subsequently, an ozone (O3) pulse was introduced into the reaction chamber for 15 seconds, followed by purging with argon (Ar) for 10 seconds. This process was repeated 80 to 100 times. In this way, a niobium oxide film of uniform thickness was formed for each precursor.

[0090] Referring to Figure 2, when using the niobium precursor compounds according to each of Examples 1 and 2 in the atomic layer deposition process, it can be confirmed that when using the niobium precursor compound of Comparative Example 1, the slope of the comparison curve is gentle. In particular, when using the niobium precursor compound according to Example 2, it can be confirmed that the growth per film cycle (GPC) is low and the GPC is maintained constant over a wide temperature range.

[0091] Maintaining a constant growth per film cycle (GPC) in the atomic layer deposition process means that incomplete reactions do not occur, and accidental reactions such as deposition in the precursor state without chemical reaction or decomposition through heat do not occur, resulting in a stable film. That is, as can be seen from Figure 2, a stable film deposition process is possible when using the niobium precursor compounds according to Examples 1 and 2 compared to when using the niobium precursor compound of Comparative Example 1. In particular, when using the niobium precursor compound according to Example 2, it can be seen that a uniform niobium film with superior physical properties can be obtained by exhibiting an almost constant growth per film cycle (GPC) within the deposition temperature range. This can be determined as follows: the niobium precursor compound of Example 2, represented by Chemical Formula 4, forms a stable structure, and some nitrogen atoms of the ligands form coordination bonds with niobium atoms.

[0092] Although the invention has been described in detail through the examples above, other types of examples are also possible. Therefore, the technical spirit and scope of the claims made below are not limited to the examples.

[0093] Cross-reference to related applications

[0094] This application claims priority to Korean Patent Application No. 10-2021-0115634, filed on August 31, 2021, with the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference. [Simplified Explanation of the Diagram]

[0025] [Figure 1] is a graph showing the thermogravimetric analysis (TGA) results of each niobium precursor compound according to Example 1, Example 2 and Comparative Example 1; and [Figure 2] is a graph showing the growth per thin film cycle (GPC) as a function of deposition temperature during the atomic layer deposition process using each niobium precursor compound according to Example 1, Example 2 and Comparative Example 1.

Claims

1. A niobium precursor compound represented by the following chemical formula 2: In chemical formula 2, R6 and R7 are each independently selected from straight-chain alkyl groups having 1 to 6 carbon atoms and branched alkyl groups having 3 to 6 carbon atoms, R8 and R9 are each independently selected from hydrogen, straight-chain alkyl groups having 1 to 10 carbon atoms and branched alkyl groups having 3 to 10 carbon atoms, R10 is selected from straight-chain alkylene groups having 1 to 20 carbon atoms and branched alkylene groups having 3 to 20 carbon atoms, and R11 and R12 are each independently selected from hydrogen and straight-chain alkyl groups having 1 to 4 carbon atoms, and in chemical formula 2, n is an integer from 1 to 5.

2. The niobium precursor compound as claimed in claim 1, wherein n in formula 2 is 1, and each of R6 in formula 2 is a methyl group.

3. The niobium precursor compound as claimed in claim 1, wherein the niobium precursor compound is represented by the following chemical formula 4:

4. The niobium precursor compound as claimed in claim 1, wherein the niobium precursor compound is a liquid at room temperature.

5. A precursor composition for depositing niobium-containing thin films, comprising a niobium precursor compound as described in any one of claims 1 to 4.

6. A method for forming a niobium-containing thin film, the method comprising depositing a thin film on a substrate using a niobium precursor compound as described in any one of claims 1 to 4 via a metal-organic chemical vapor deposition (MOCVD) process or an atomic layer deposition (ALD) process.

7. The method of claim 6, wherein the deposition process is performed in a temperature range of 50°C to 700°C.

8. The method of claim 6, wherein the deposition process includes moving the niobium precursor compound to the substrate by a method selected from the group consisting of: bubbling, gas phase quality flow controller (MFC), direct gas injection (DGI), direct liquid injection (DLI), and an organic solution supply method wherein the niobium precursor compound is dissolved in an organic solvent and moved.

9. The method of claim 8, wherein the niobium precursor compound is moved onto the substrate together with a carrier gas via the bubbling method or the direct gas injection method, and the carrier gas is a mixture containing one or more of the group consisting of argon (Ar), nitrogen (N2), helium (He) and hydrogen (H2).

10. The method of claim 6, wherein the deposition process includes the step of supplying one or more reactive gases during the formation of the niobium-containing thin film, the reactive gases being selected from the group consisting of water vapor (H2O), oxygen (O2), ozone (O3), and hydrogen peroxide (H2O2).

11. The method of claim 6, wherein the deposition process includes the step of supplying one or more reactive gases during the formation of the niobium-containing thin film, the reactive gases being selected from the group consisting of ammonia (NH3), hydrazine (N2H4), nitrous oxide (N2O), and nitrogen (N2).

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