Niobium Precursor Compound For Thin Film Deposition And Method For Forming Niobium-Containing Thin Film Using Same

Abstract

According to an embodiment of the present disclosure, a niobium precursor compound is represented by Chemical Formula 1 or Chemical Formula 2 below:

##STR00001##

Therefore, the niobium precursor compound according to an embodiment of the present disclosure has excellent thermal stability, exists in a liquid state at room temperature, and has high volatility, thereby having an advantage which is advantageous for application to a thin film forming process. Further, the niobium thin film formed using the niobium precursor compound according to an embodiment of the present disclosure has a small residual content and has uniform physical properties.

Claims

1. A niobium precursor compound represented by Chemical Formula 1 or Chemical Formula 2 below: ##STR00011## in Chemical Formula 1, R.sub.1 and R.sub.2 are each independently selected from a linear alkyl group having 1 to 6 carbon atoms and a branched alkyl group having 3 to 6 carbon atoms, and R.sub.3, R.sub.4, and R.sub.5 are each independently selected from hydrogen, a linear alkyl group having 1 to 10 carbon atoms, and a branched alkyl group having 3 to 10 carbon atoms, in Chemical Formula 2, R.sub.6 and R.sub.7 are each independently selected from a linear alkyl group having 1 to 6 carbon atoms and a branched alkyl group having 3 to 6 carbon atoms, R.sub.8 and R.sub.9 are each independently selected from hydrogen, a linear alkyl group having 1 to 10 carbon atoms, and a branched alkyl group having 3 to 10 carbon atoms, R.sub.10 is selected from a linear alkylene group having 1 to 20 carbon atoms and a branched alkylene group having 3 to 20 carbon atoms, and R.sub.11 and R.sub.12 are each independently selected from hydrogen and a linear alkyl group having 1 to 4 carbon atoms, and in Chemical Formulas 1 and 2, n is an integer of 1 to 5.

2. The niobium precursor compound of claim 1, wherein n in Chemical Formulas 1 and 2 is 1, and R.sub.1 in Chemical Formula 1 and R.sub.6 in Chemical Formula 2 are each a methyl group.

3. The niobium precursor compound of claim 1, wherein the niobium precursor compound is represented by Chemical Formula 3 below: ##STR00012##

4. The niobium precursor compound of claim 1, wherein the niobium precursor compound is represented by Chemical Formula 4 below: ##STR00013##

5. The niobium precursor compound of claim 1, wherein the niobium precursor compound is liquid at room temperature.

6. A precursor composition for depositing a niobium-containing thin film, comprising the niobium precursor compound of claim 1.

7. A method for forming a niobium-containing thin film, the method comprising depositing a thin film on a substrate through a metal organic chemical vapor deposition (MOCVD) process or an atomic layer deposition (ALD) process using the niobium precursor compound of claim 1.

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

9. The method of claim 7, wherein the deposition process includes a step of moving the niobium precursor compound to the substrate through one method selected from the group consisting of a bubbling method, a vapor phase mass flow controller (MFC) method, a direct gas injection (DGI) method, a direct liquid injection (DLI) method, and an organic solution supply method in which the niobium precursor compound is dissolved in an organic solvent and moved.

10. The method of claim 9, wherein the niobium precursor compound is moved together with a carrier gas onto the substrate by the bubbling method or the direct gas injection method, and the carrier gas is a mixture containing one or more selected from the group consisting of argon (Ar), nitrogen (N.sub.2), helium (He), and hydrogen (H.sub.2).

11. The method of claim 7, wherein the deposition process includes a step of supplying one or more reaction gases selected from the group consisting of water vapor (H.sub.2O), oxygen (O.sub.2), ozone (O.sub.3), and hydrogen peroxide (H.sub.2O.sub.2) when forming the niobium-containing thin film.

12. The method of claim 7, wherein the deposition process includes a step of supplying one or more reaction gases selected from the group consisting of ammonia (NH.sub.3), hydrazine (N.sub.2H.sub.4), nitrous oxide (N.sub.2O), and nitrogen (N.sub.2) when forming the niobium-containing thin film.

13. A precursor composition for depositing a niobium containing thin film, comprising the niobium precursor compound of claim 2.

14. A precursor composition for depositing a niobium containing thin film, comprising the niobium precursor compound of claim 3.

15. A precursor composition for depositing a niobium containing thin film, comprising the niobium precursor compound of claim 4.

16. A precursor composition for depositing a niobium containing thin film, comprising the niobium precursor compound of claim

17. A method for forming a niobium-containing thin film, the method comprising depositing a thin film on a substrate through a metal organic chemical vapor deposition (MOCVD) process or an atomic layer deposition (ALD) process using the niobium precursor compound of claim 2.

18. A method for forming a niobium-containing thin film, the method comprising depositing a thin film on a substrate through a metal organic chemical vapor deposition (MOCVD) process or an atomic layer deposition (ALD) process using the niobium precursor compound of claim 3.

19. A method for forming a niobium-containing thin film, the method comprising depositing a thin film on a substrate through a metal organic chemical vapor deposition (MOCVD) process or an atomic layer deposition (ALD) process using the niobium precursor compound of claim 4.

20. A method for forming a niobium-containing thin film, the method comprising depositing a thin film on a substrate through a metal organic chemical vapor deposition (MOCVD) process or an atomic layer deposition (ALD) process using the niobium precursor compound of claim 5.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] FIG. 1 is a graph showing thermogravimetric analysis (TGA) results of each niobium precursor compound according to Example 1, Example 2, and Comparative Example 1; and

[0025] FIG. 2 is a graph showing a thin film growth per cycle (GPC) according to a deposition temperature during the atomic layer deposition process using each niobium precursor compound according to Example 1, Example 2, and Comparative Example 1.

DETAILED DESCRIPTION OF THE EMBODIMENT

[0026] Advantages and features of the present disclosure and methods of achieving them will become apparent with reference to the Examples to be described later in detail in conjunction with the accompanying drawings. However, the present disclosure is not limited to the Examples disclosed below, but will be implemented in a variety of different shapes, only the present Examples are provided so that the disclosure of the present disclosure is complete, and to completely inform those of ordinary skill in the art to which the present disclosure pertains of the scope of the invention, and the present disclosure is only defined by the scope of the claims.

[0027] In describing the present disclosure, if it is determined that a detailed description of a related known technology may unnecessarily obscure the gist of the present disclosure, the detailed description thereof will be omitted. When ‘including’, ‘having’, ‘consisting’, etc. mentioned in the present disclosure are used, other parts may be added unless ‘only’ is used. When a component is expressed in the singular number, cases including the plural number are included unless otherwise explicitly stated.

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

[0029] Throughout the present 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 an embodiment of the present disclosure may be represented by

[0031] Chemical Formula 1 below.

##STR00003##

[0032] In Chemical Formula 1, R.sub.1 and R.sub.2 may each independently be any one selected from a linear alkyl group having 1 to 6 carbon atoms and a branched alkyl group having 3 to 6 carbon atoms. For example, R.sub.1 may be a linear alkyl group having 1 to 3 carbon atoms, and R.sub.2 may be a branched alkyl group having 3 to 6 carbon atoms, but is not limited thereto.

[0033] In Chemical Formula 1, R.sub.3, R.sub.4, and R.sub.5 may each independently be any one selected from hydrogen, a linear alkyl group having 1 to 10 carbon atoms, and a branched alkyl group having 3 to 10 carbon atoms. Specifically, for example, R.sub.3 and R.sub.4 may each be a linear alkyl group having 1 to 6 carbon atoms, and R.sub.5 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 of 1 to 5.

[0035] For example, in Chemical Formula 1, n may be 1, and R.sub.1 may be a linear alkyl group having 1 to 6 carbon atoms. Preferably, for example, R.sub.1 in Chemical Formula 1 may be a methyl group. In the case of including such a methylcyclopentadiene structure, the bonding force with a metal may be reduced compared to a cyclopentadiene structure that does not contain a methyl group. Accordingly, the unnecessary residual content in the thin film formed through the deposition process may be significantly reduced. Further, in the case of including a methylcyclopentadiene structure, the synthesis of a heteroleptic niobium precursor compound may be facilitated due to the masking effect of methylcyclopentadiene. Furthermore, a heteroleptic niobium precursor compound having high purity may be obtained by improving the purification efficiency of the niobium precursor compound.

[0036] More specifically, the niobium precursor compound may be a compound represented by Chemical Formula 3 below.

##STR00004##

[0037] The niobium precursor compound having the structure as in Chemical Formula 3 has more excellent thermal stability and can further reduce the residual content when forming a thin film. Further, it exhibits a constant thin film growth per cycle (GPC) in a wide temperature range in the deposition process, and may be utilized in the ALD process as well as the MOCVD process.

[0038] The niobium precursor compound according to another embodiment of the present disclosure may be represented by Chemical Formula 2 below.

##STR00005##

[0039] The niobium precursor compound according to Chemical Formula 2 forms a stable structure while the nitrogen atom of the ligand —OR.sub.10N(R.sub.11)(R.sub.12) bonded to the niobium atom forms a coordination bond with the niobium atom. Accordingly, the niobium precursor compound represented by Chemical Formula 2 has a more stable structure than that of the niobium precursor compound of Chemical Formula 1, thereby having an advantage of more excellent thermal stability. Therefore, the thin film formed by the deposition process using the niobium precursor compound represented by Chemical Formula 2 has a more reduced residual content and exhibits a constant thin film growth per cycle (GPC) in a wider temperature range. Accordingly, a thin film prepared using the niobium precursor compound represented by Chemical Formula 2 exhibits higher quality properties.

[0040] In Chemical Formula 2, R.sub.6 and R.sub.7 may each independently be any one selected from a linear alkyl group having 1 to 6 carbon atoms and a branched alkyl group having 3 to 6 carbon atoms. Specifically, for example, R.sub.6 may be a linear alkyl group having 1 to 3 carbon atoms, and R.sub.7 may be a branched alkyl group having 3 to 6 carbon atoms, but is not limited thereto.

[0041] In Chemical Formula 2, R.sub.8 and R.sub.9 may each independently be any one selected from hydrogen, a linear alkyl group having 1 to 10 carbon atoms, and a branched alkyl group having 3 to 10 carbon atoms. Specifically, for example, R.sub.8 and R.sub.9 may each be a linear alkyl group having 1 to 6 carbon atoms, but are not limited thereto.

[0042] In Chemical Formula 2, Rio may be selected from a linear alkylene group having 1 to 20 carbon atoms and a branched alkylene group having 3 to 20 carbon atoms. Specifically, for example, R.sub.10 may be a linear alkylene group having 1 to 6 carbon atoms, but is not limited thereto.

[0043] In Chemical Formula 2, R.sub.11 and R.sub.12 may each independently be any one selected from hydrogen and a linear alkyl group having 1 to 4 carbon atoms. Specifically, for example, R.sub.11 and R.sub.12 may each be a linear alkyl group having 1 to 6 carbon atoms, but are not limited thereto.

[0044] In Chemical Formula 2, n is an integer of 1 to 5.

[0045] For example, in Chemical Formula 2, n may be 1, and R.sub.6 may be a linear alkyl group having 1 to 6 carbon atoms. Preferably, for example, R.sub.6 in Chemical Formula 2 may be a methyl group. As described above, when the methylcyclopentadiene structure is included, the bonding force with the metal is reduced compared to cyclopentadiene that does not contain a methyl group so that the unnecessary residual content in the thin film may be significantly reduced. Further, the synthesis and purification of the heteroleptic niobium precursor compound are facilitated due to the masking effect of methylcyclopentadiene so that a niobium precursor compound with high purity and high quality may be obtained.

[0046] More specifically, the niobium precursor compound may be a compound represented by Chemical Formula 4 below.

##STR00006##

[0047] The niobium precursor compound represented by Chemical Formula 4 may further improve thermal stability, and further reduce the residual content when forming a thin film. Accordingly, the thin film prepared by the deposition process using the niobium precursor compound of Chemical Formula 4 has more excellent physical properties.

[0048] The niobium precursor compound represented by Chemical Formula 1 or Chemical Formula 2 may be used as a precursor composition for depositing a niobium-containing thin film.

[0049] Further, since the niobium precursor compound according to an embodiment of the present disclosure exists in a liquid state at room temperature, it is easy to store and handle, and has high volatility so that it may be advantageously applied to form a thin film using a deposition process.

[0050] Hereinafter, a method for forming a niobium-containing thin film according to an embodiment of the present disclosure will be described in detail. The method for forming the niobium-containing thin film uses the above-described niobium precursor compound, and an overlapping description related to the niobium precursor compound is omitted.

[0051] In the method for forming the niobium-containing thin film according to an embodiment of the present disclosure, a thin film is deposited on a substrate through a deposition process using the niobium precursor compound represented by Chemical Formula 1 or Chemical Formula 2.

[0052] The deposition process may include an atomic layer deposition (ALD) process or a chemical vapor deposition (CVD) process, for example, a metal organic chemical vapor deposition (MOCVD) process. The deposition process may be carried out at 50 to 700° C.

[0053] First, the niobium precursor compound represented by Chemical Formula 1 or Chemical Formula 2 is transferred onto a substrate. For example, the niobium precursor compound may be supplied onto the substrate by a method such as a bubbling method, a vapor phase mass flow controller method, a direct gas injection (DGI) method, a direct liquid injection (DLI) method, or a liquid transfer method in which it is dissolved in an organic solvent and transferred, but is not limited thereto.

[0054] More specifically, the niobium precursor compound may be mixed with a carrier gas or diluent gas including one or more selected from the group consisting of argon (Ar), nitrogen (N.sub.2) , helium (He), and hydrogen (H.sub.2), and transferred onto the substrate by a bubbling method or a direct gas injection method.

[0055] Meanwhile, the deposition process may include a step of supplying one or more reaction gases selected from the group consisting of water vapor (H.sub.2O), oxygen (O.sub.2), ozone (O.sub.3), and hydrogen peroxide (H.sub.2O.sub.2) when forming a niobium thin film.

[0056] As another example, the deposition process may include a step of supplying one or more reaction gases selected from the group consisting of ammonia (NH.sub.3), hydrazine (N.sub.2H.sub.4), nitrous oxide (N.sub.2O), and nitrogen (N.sub.2) when forming a niobium thin film.

[0057] The niobium thin film manufactured by the method for forming a thin film according to an embodiment of the present disclosure may provide a high-quality thin film by effectively reducing the amount of residue. Further, according to the method for forming a thin film according to an embodiment of the present disclosure, a niobium thin film having more uniform physical properties by exhibiting a constant thin film growth per cycle (GPC) within a wide thin film growth temperature range may be provided.

[0058] Hereinafter, the niobium precursor compound according to the present disclosure will be described in more detail through the following Examples. However, this is only presented to help the understanding of the present disclosure, and the present disclosure is not limited to the following Examples.

EXAMPLE 1

[0059] 1. Preparation of Intermediate Compound

[0060] 32.9 g (0.111 mol, 1 equivalent) of (tert-butylimido)tris(dimethylamido)niobium((tBuN)(NMe.sub.2).sub.3Nb) and 300 mL of n-hexane were injected into a flame-dried 500 mL Schlenk flask, and then stirred at room temperature. After adding 11 g (0.137 mol, 1.2 equivalents) of methylcyclopentadiene (C.sub.5MeH.sub.5) dropwise to the flask at −20° C. or lower, the reaction solution was stirred at room temperature for 12 hours. Thereafter, the solvent was removed from the reaction solution under reduced pressure, and the solvent-removed reaction solution was distilled under reduced pressure to obtain 26.5 g (yield 72%) of a pale yellow liquid compound represented by (η-C.sub.5H.sub.4CH.sub.3)(tBuN)Nb(N(CH.sub.3).sub.2).sub.2.

[0061] The synthesis of an intermediate compound (η-C.sub.5H.sub.4CH.sub.3)(tBuN)Nb(N(CH.sub.3).sub.2).sub.2 represented by Chemical Formula A below was confirmed through nuclear magnetic resonance analysis (.sup.1H NMR).

##STR00007##

[0062] 2. Preparation of Compound (η-C.sub.5H.sub.4CH.sub.3)(tBuN)Nb(N(CH.sub.3).sub.2) (tBuO)

[0063] 26.5 g (0.08 mol, 1 equivalent) of the intermediate compound (tert-butylimido)bis(dimethylamido)(methylcyclopentadienyl)niobium (η-C.sub.5H.sub.4CH.sub.3)(tBuN)Nb(N(CH.sub.3).sub.2).sub.2 prepared as described above and 150 mL of n-hexane were injected into a flame-dried 500 mL Schlenk flask, and then stirred at room temperature. After adding 6.5 g (0.088 mol, 1.1 equivalents) of tert-butanol (tBuOH) dropwise to the flask at −20° C. or lower, the reaction solution was stirred at room temperature for 12 hours. Thereafter, the solvent was removed from the reaction solution under reduced pressure, and the solvent-removed reaction solution was distilled under reduced pressure to obtain 16.7 g (yield 58%) of a pale yellow liquid compound.

[0064] The synthesis of the niobium precursor compound (η-C.sub.5H.sub.4CH.sub.3)(tBuN)Nb(N(CH.sub.3).sub.2)(tBuO) represented by Chemical Formula 3 below was confirmed through nuclear magnetic resonance analysis (.sup.1H NMR).

##STR00008##

EXAMPLE 2

[0065] 32.9 g (0.099 mol, 1 equivalent) of (tert-butylimido)bis(dimethylamido)(methylcyclopentadienyl)niobium (η-C.sub.5H.sub.4CH.sub.3)(tBuN)Nb(N(CH.sub.3).sub.2).sub.2 obtained in the intermediate preparation step of Example 1 above and 300 mL of n-hexane were injected into a flame-dried 500 mL Schlenk flask, and then stirred at room temperature. After adding 17.7 g (0.199 mol, 2 equivalents) of dimethylethanolamine ((CH.sub.3).sub.2NCH.sub.2CH.sub.2OH) dropwise to the flask at −20° C. or lower, the reaction solution was stirred at room temperature for 24 hours. Thereafter, the solvent was removed from the reaction solution under reduced pressure, and the solvent-removed reaction solution was distilled under reduced pressure to obtain 15.7 g (yield 42%) of a pale yellow liquid compound.

[0066] The synthesis of the niobium precursor compound (η-C.sub.5H.sub.4CH.sub.3)(tBuN)Nb(N(CH.sub.3).sub.2)((CH.sub.3).sub.2NCH.sub.2CH.sub.2O) represented by Chemical Formula 4 below was confirmed through nuclear magnetic resonance analysis (.sup.1H NMR).

##STR00009##

Comparative Example 1

[0067] 11 g (0.029 mol, 1 equivalent) of bis(diethylamido) (tert-butylimido) (cyclopentadienyl)niobium (η-C.sub.5H.sub.5)(tBuN)Nb(NEt.sub.2).sub.2 and 150 mL of n-hexane were injected into a flame-dried 500 mL Schlenk flask, and then stirred at room temperature. After adding 3.8 g (0.063 mol, 2.2 equivalents) of isopropyl alcohol [C.sub.3H.sub.7OH] dropwise to the flask at −20° C. or lower, 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 obtain 9 g (yield 90%) of a pale yellow liquid compound.

[0068] The synthesis of the niobium precursor compound (η-C.sub.5H.sub.5)(tBuN)Nb(OCHC.sub.2H.sub.6).sub.2 represented by Chemical Formula 5 below was confirmed through nuclear magnetic resonance analysis (.sup.1H NMR).

##STR00010##

Experimental Example

[0069] 1. Thermogravimetric Analysis

[0070] In order to find out the thermal properties of the compounds according to Comparative Example 1 and Examples 1 and 2 respectively, thermogravimetric analysis (TGA) was performed. First, a thermogravimetric analyzer was stored in a nitrogen glove box where the moisture and oxygen contents were kept below 1 ppm. After putting a sample of 15 mg into a crucible, it was measured while raising the temperature from 35° C. to 350° C. at a rate of 10° C./min. The mass loss of the sample was monitored as a function of the crucible temperature. The results according to this are shown in FIG. 1.

[0071] FIG. 1 is a graph showing thermogravimetric analysis (TGA) results of each niobium precursor compound according to Comparative Example 1 and Examples 1 and 2.

[0072] Referring to FIG. 1, it can be confirmed that the niobium precursor compound prepared according to each of

[0073] Examples 1 and 2 has less than 2% by weight of a residual content that has not been volatilized at a temperature of 330° C. or higher. Further, it can be confirmed from the graph of FIG. 1 that the niobium precursor compound prepared according to each of Examples 1 and 2 is not decomposed or does not form by-products upon volatilization. That is, it can be seen that the niobium precursor compounds prepared according to Examples 1 and 2 are thermally stable by being volatilized with the residue hardly being remained.

[0074] Contrary to this, in the case of the niobium precursor compound according to Comparative Example 1, a mass decrease occurs near a temperature of 100° C., which is much lower than in Examples 1 and 2, and the half-life is low compared to those in Examples. It can be confirmed from this that the niobium precursor compound according to Comparative Example 1 has inferior thermal properties compared to those in Examples.

[0075] In summary, the niobium precursor compounds according to Examples 1 and 2 exist in a liquid state at room temperature to facilitate handling and purification, do not allow thermal decomposition to occur during heating, and are converted into a vapor state by being volatilized with the residue hardly being remained. Therefore, it can be seen that the niobium precursor compounds according to Examples 1 and 2 can be easily applied to the MOCVD or ALD process.

[0076] 2. Thin Film Deposition Properties

[0077] Growth per cycles (GPC) of thin films during the atomic layer deposition process using the niobium precursor compounds according to Comparative Example 1, Example 1, and Example 2 were analyzed. The results according to this are shown in FIG. 2.

[0078] FIG. 2 is a graph showing a thin film growth per cycle (GPC) according to a deposition temperature (Dep. Temp.)

[0079] during the atomic layer deposition process using each niobium precursor compound according to Comparative Example 1, Example 1, and Example 2.

[0080] As deposition conditions, a niobium precursor compound was filled in a canister, and then it was heated to 110° C., and ozone (O.sub.3) was used as an oxidizing agent. A silicon wafer was used as a reaction substrate, and deposition was performed by heating the silicon wafer from 250° C. to 340° C. After introducing a pulse of the precursor for 10 seconds, argon (Ar) was purged for 10 seconds. Subsequently, a pulse of ozone (O.sub.3) was introduced into a reaction chamber for 15 seconds, and then argon (Ar) was purged for 10 seconds. 80 to 100 cycles were performed in this way. In this way, a niobium oxide thin film with the same thickness was formed for each precursor.

[0081] Referring to FIG. 2, when the niobium precursor compound according to each of Examples 1 and 2 is used during the atomic layer deposition process, it can be confirmed that, when the niobium precursor compound of Comparative Example 1 is used, the slope of the contrast curve is gentle. In particular, when the niobium precursor compound according to Example 2 is used, it can be confirmed that the thin film growth per cycle (GPC) is low, and the thin film growth per cycle (GPC) is constantly maintained within a wide temperature range.

[0082] Maintaining a constant thin film growth per cycle (GPC) in the atomic layer deposition process means that an incomplete reaction does not occur, an incidental reaction such as being deposited in a precursor state without a chemical reaction, or decomposed by heat does not occur, and a stable thin film is formed. That is, it can be seen from FIG. 2 that, when the niobium precursor compounds according to Examples 1 and 2 are used, a stable thin film deposition process is possible compared to when the niobium precursor compound of Comparative Example 1 is used. In particular, when the niobium precursor compound according to Example 2 is used, it can be seen that a uniform niobium thin film with more excellent physical properties can be obtained by exhibiting an almost constant thin film growth per cycle (GPC) within the deposition temperature range. This can be determined as a result of the niobium precursor compound of Example 2 represented by Chemical Formula 4 forming a stable structure while the nitrogen atoms of some ligands are forming a coordination bond with the niobium atoms.

[0083] Although the present disclosure has been described in detail through Examples above, other types of Examples are also possible. Therefore, the technical spirit and scope of the claims set forth below are not limited to Examples.