KR100695575B1 - Novel erbium(iii) complexes and preparation method thereof - Google Patents

Abstract

A novel erbium oxide precursor material is provided to show excellent thermal stability and volatility by coordinating only oxygen and nitrogen atom ligand with erbium, be less sensitive to moisture and favorable to store, thereby being usefully used for preparing a good quality oxide film. The erbium oxide precursor material is represented by the formula(1), Er[O-A-N(R^3)-B-NR^1R^2]3, and is prepared by reacting a erbium compound represented by the formula(3), ErCl3, with an alkali metal salt compound represented by the formula(4), M[N(Si(CH3)3)2], to obtain a compound represented by the formula(5), M[N(Si(CH3)3)2]3, and then reacting the compound of the formula(5) with an alcohol compound represented by the formula(6), HO-A-N(R^3)-B-NR^1R^2, where M is Li, Na, or K, A is C2-5 alkylene, B is C1-4 alkylene, the A and B is able to be further substituted by at least one linear or branched C1-5 alkyl, and each R^1, R^2 and R^ is independently H or linear or branched C1-5 alkyl.

Description

Novel erbium compound and its manufacturing method {NOVEL ERBIUM (III) COMPLEXES AND PREPARATION METHOD THEREOF

1 is a result of Fourier transform infrared spectroscopy (FT-IR) analysis of Er (demamp) ₃ compound prepared in Example 1,

2 is a graph showing the results of thermogravimetric analysis (TGA) and differential thermal analysis (DTA) of the Er (demamp) ₃ compound prepared in Example 1,

3 is a result of Fourier transform infrared spectroscopy (FT-IR) analysis of an Er (demae) ₃ compound prepared in Example 2,

Figure 4 is a graph showing the results of thermogravimetric analysis (TGA) and differential thermal analysis (DTA) of the Er (demae) ₃ compound prepared in Example 2.

The present invention relates to a novel erbium compound, and to a method for preparing a compound useful as a precursor of an erbium oxide thin film.

Silicon oxide has been widely used as an insulator because of its stable and high quality silicon-silicon oxide interface and excellent electrical insulation properties. In recent years, however, the channel length and gate dielectric thickness have also been dramatically reduced in the semiconductor process technology of 0.1 micron or less. Therefore, research is being actively conducted on suitable thin film materials and process technologies to solve the leakage current problem caused by the direct tunneling phenomenon of the thinned silicon oxide gate insulator.

In order to solve the problem, it is necessary to develop a high dielectric material having excellent insulation, high dielectric constant, and low dielectric loss. For example, as a substitute for silicon oxide (SiO ₂ ), tantalum pentoxide having a higher dielectric constant value than silicon dioxide ( Ta ₂ O ₅ ), BST {(Ba, Sr) TiO ₃ }, PZT {Pb (Zr, Ti) O ₃ }; And aluminum oxide (Al ₂ O ₃ ), hafnium oxide (HfO ₂ ), zirconium oxide (ZrO ₂ ), lanthanum oxide (La ₂ O ₃ ), praseodymium oxide (Pr ₂ O ₃ ), and gadolinium oxide, which are advantageous in terms of process stability. (Gd ₂ O ₃ ), neodymium oxide (Nd ₂ O ₃ ), erbium oxide (Er ₂ O ₃ ), and the like.

In particular, the lanthanide oxide has a large bandgaps (E _g (Pr ₂ O ₃ ) = 3.9 eV, E _g (Gd ₂ O ₃ ) = 5.6 eV), and has a relatively high dielectric constant (κ (Er ₂ O). ₃ ) = 10-14, κ (Gd ₂ O ₃ ) = 16, κ (La ₂ O ₃ ) = 27, κ (Pr ₂ O ₃ ) = 26-30), more than zirconium oxide and hafnium oxide on silicon It has high thermodynamic stability and is a promising material for the next generation high-κ gate insulator. In addition, some lanthanide-based oxides have relatively similar lattice parameters to silicon, allowing epitaxial growth of thin films.

Erbium oxide (Er ₂ O ₃ ) is currently being studied as a gate dielectric in metal-oxide-semiconductor devices. It is also used as a dopant in optical magnifiers because of its high refractive index (KJ Hubbard, DG Schlom, J. Mater. Res. 1996, 11, 2757).

Oxidized erbium (Er ₂ O ₃₎ thin film is laser ablation (laser ablation), electron beam heating deposition method (electron beam evaporation), the high temperature thermal cracking (pyrolysis), the sol-gel method (sol-gel method), chemical vapor deposition (chemical vapor deposition , CVD, and physical vapor deposition (PVD). Among them, the method used for manufacturing various oxide thin films includes a metal organic chemical vapor deposition (MOCVD) process or an atomic layer deposition (ALD) process. It has the advantage of being uniform, easy to control ingredients, and easy to switch to mass production. ALD is a chemical gas phase deposition method, which flows different precursors onto a substrate and removes the remaining reactants with an inert gas at each step, thereby controlling the thickness of the thin film by controlling the number of cycles.

In order to manufacture a thin film using such a MOCVD process or ALD process, it is essential to develop a precursor material and to understand its characteristics. The precursors for MOCVD must have a sufficiently high vapor pressure below 200 ° C, be thermally stable enough during heating to vaporize, and decompose quickly without decomposition of organic materials, etc., at substrate temperatures of 350 to 500 ° C. Should be stable enough to air and moisture while. In addition, it should be non-toxic or less toxic to the precursor itself or to the decomposition products, the synthesis method should be simple and the raw material cost should be low. However, despite the many advantages of such an organometallic chemical vapor deposition (MOCVD) or atomic layer deposition (ALD) process, there is no adequately stable and highly volatile precursor, resulting in high quality erbium oxide (Er ₂ O ₃ ). Thin film research is rare.

The precursor materials which have been used to make erbium oxide into a thin film are largely classified into four types, including inorganic salts such as erbium chloride or erbium nitrate, alkoxide compounds, dialkylamido compounds, and compounds containing β-diketonate. have.

Recently, Er ₂ O ₃ thin films were prepared at 450 to 600 ° C. using [Er (acac) ₃ ] (acac = acetylacetonate) by MOCVD and showed severe carbon contamination (H. Ono, T. Katsumata, Appl. Phys). Lett. 2001, 78, 1832; MP Singh, CS Thakur, K. Shalini, N. Bhat, SA Shivashankar, Appl. Phys. Lett. 2003, 83, 2889).

In addition, a C-type Er ₂ O ₃ thin film was prepared at 300 ° C. using [Er (tmhd) ₃ ] (tmhd = 2,2,6,6-tetramethylheptane-3,5-dionate) and ozone by an ALD process. (J. Paivasaari, M. Putkonen, T. Sajavaara, L. Niinisto, J. Alloys Compd. 2004, 374, 124; J. Paivasaari, M. Putkonen, L. Niinisto, Thin Solid Films 2005, 472, 275). . Tmhd-complexes of the β-diketonate type are volatiles and are often used as precursors in ALD processes. However, β-diketonates do not react easily with water and require a stronger oxidizer such as ozone to form an oxide film. In the Ln (tmhd) ₃ / O ₃ process, the growth rate of the thin film is somewhat slow. In addition, the use of ozone has the disadvantage of increasing the formation of SiO _x at the interface between the silicon surface and the deposited oxide film.

In order to solve the problems of β-diketonate compounds, the present inventors have synthesized a new ligand so that only oxygen and nitrogen atom ligands are coordinated with erbium, which does not cause contamination of carbon or halogens, and improves thermal stability and volatility. Erbium oxide precursors have been developed.

SUMMARY OF THE INVENTION An object of the present invention is to provide an erbium oxide precursor material which is thermally stable and has increased volatility to form a high quality erbium oxide film and a method of manufacturing the same.

In order to achieve the above object, the present invention provides a novel erbium oxide precursor represented by the following general formula (1):

[Formula 1]

Er [OAN (R ³ ) -B-NR ¹ R ² ] ₃

[Wherein A is alkylene of C ₂ -C ₅ ; B is alkylene of C ₁ -C ₄ ; A and B may be further substituted with one or more C ₁ -C ₅ straight or branched alkyl groups; R ¹ , R ² and R ³ independently of one another are H or C ₁ -C ₅ linear or branched alkyl groups.]

More specifically, the erbium oxide precursor of Formula 1 includes the erbium oxide precursor of Formula 2 below.

[Formula 2]

Er [OCR ⁴ R ⁵ (CH ₂ ) _m N (R ³ )-(CH ₂ ) _n NR ¹ R ² ] ₃

[Wherein R ¹ , R ² , R ³ , R ⁴ And R ⁵ is independently of each other H or a C ₁ -C ₅ linear or branched alkyl group, m and n are integers from 1 to 4.]

More preferably in Formula 2 R ¹ , R ² , R ³ , R ⁴ And R ⁵ are independently of each other erbium oxide precursors selected from H, CH ₃ , C ₂ H ₅ , CH (CH ₃ ) ₂ or C (CH ₃ ) ₃ .

Hereinafter, the present invention will be described in more detail.

The erbium oxide precursor of Chemical Formula 1 according to the present invention is 1 equivalent of the compound of Chemical Formula 5 and 3 equivalent of the alcohol compound of Chemical Formula 6 obtained by reacting an erbium compound of Chemical Formula 3 with three equivalents of an alkali metal salt compound of Chemical Formula 4. May be prepared by substitution reaction, and a reaction scheme for preparing the erbium oxide precursor of Chemical Formula 1 may be represented by the following Scheme 1.

Meanwhile, the alcohol compound of Formula 6 may be prepared by reacting a diamine compound with an ethylene oxide derivative (1,1-disubstituted ethylene oxide) having two substituents in 1-position in an aqueous solution.

[Formula 1]

Er [OAN (R ³ ) -B-NR ¹ R ² ] ₃

[Formula 3]

ErCl ₃

[Formula 4]

M [N (Si (CH ₃ ) ₃ ) ₂ ]

[Formula 5]

Er [N (Si (CH ₃ ) ₃ ) ₂ ] ₃

[Formula 6]

HO-AN (R ³ ) -B-NR ¹ R ²

[In Formula 1, Formula 4 and Formula 6, M is Li, Na or K; A is alkylene of C ₂ -C ₅ ; B is alkylene of C ₁ -C ₄ ; A and B may be further substituted with one or more C ₁ -C ₅ straight or branched alkyl groups; R ¹ , R ² and R ³ independently of one another are H or C ₁ -C ₅ linear or branched alkyl groups.]

Scheme 1

ErCl ₃ + 3 M [N (Si (CH ₃ ) ₃ ) ₂ ] → Er [N (Si (CH ₃ ) ₃ ) ₂ ] ₃ + 3 MCl

Er [N (Si (CH ₃ ) ₃ ) ₂ ] ₃ + 3 HO-AN (R ³ ) -B-NR ¹ R ² → Er [OAN (R ³ ) -B-NR ¹ R ² ] ₃ + 3 HN (Si (CH ₃ ) ₃ ) ₂

The novel erbium oxide precursor of formula (1) is a stable complex, a non-polar alkyl group is bonded to the α-carbon position with respect to the oxygen of the alkoxide to be bonded to the metal has a high affinity for the organic solvent, the ligand adjacent to the central metal It can exist as a monomer because it gives steric hindrance to prevent intermolecular interaction with oxygen. Due to these structural characteristics, the precursor material for erbium oxide of Chemical Formula 1 is a stable liquid at room temperature, and has high solubility in organic solvents such as pentane, hexane, diethyl ether, tetrahydrofuran, toluene, and no halogen element. Since it is advantageous for storage, these can be used to obtain an erbium oxide thin film of better quality. The trivalent erbium compound thus prepared is obtained as a viscous liquid at room temperature.

The erbium oxide precursor of Chemical Formula 1, which is a reaction product, was identified using Fourier transform infrared spectroscopy (FTIR) (see FIGS. 1 and 3), and the thermal stability of the erbium oxide precursor synthesized in the present invention, Volatile and decomposition temperatures were analyzed using thermogravimetric analysis / differential thermal analysis (TGA / DTA) (see FIGS. 2 and 4).

50 in the case of tris (1- (N- (2-dimethylamino) ethyl) -N-methylamino) -2-methyl-2-propoxy) erbium (Er (demamp) ₃ ) compound as shown in FIG. It showed mass reduction from around ℃ and completed at around 320 ℃, the residual amount is 38.29%. In addition, in the case of the tris [2- (N- (2- (dimethylamino) ethyl) -N-methylamino) epoxy] erbium (Er (demae) ₃ ) compound as shown in FIG. It suddenly falls near 300 ° C and is completed near 375 ° C, and the residual amount is 40.19%.

From the above results, the erbium oxide precursor synthesized in the present invention not only exhibits sufficient volatility before decomposition temperature but also has high solubility in organic solvents, so it is widely used in the semiconductor organic chemical vapor deposition (MOCVD) process or atomic layer deposition method ( ALD) is preferably applied.

The invention can be better understood by the following examples, which are intended for purposes of illustration of the invention and are not intended to limit the scope of protection defined by the appended claims.

All experiments were performed in an inert argon or nitrogen atmosphere using a glove box or Schlenk line. The structure of each reaction product obtained in Examples 1 and 2 was Fourier transform infrared spectroscopy (FT-IR) analysis and elemental analysis (EA), thermogravimetric analysis / differential thermal analysis, TGA / DTA).

Preparation of Erbium Oxide

Example 1 Synthesis of Tris (1- (N- (2-dimethylamino) ethyl) -N-methylamino) -2-methyl-2-propoxy) erbium [Er (demamp) ₃ ]

1.73 g (10.3 mmol) of bis (trimethylsilyl) amido lithium was dissolved in a 125 mL Schlenk flask containing tetrahydrofuran (70 mL), followed by 1.07 g of erbium chloride (3.91 mmol). Stir for hours. The solvent was removed under reduced pressure to obtain 1.20 g (yield 50.21%) of the compound as a pink solid represented by the formula (5).

0.92 g (1.42 mmol) of the compound of formula 5 were dissolved in a 125 mL Schlenk flask containing toluene (70 mL), which was dissolved in 1- [N- {2- (dimethylamino) ethyl} -N-methylamino. ] -2-methylpropan-2-ol (demampH, (1- (N- (2- (dimethylamino) ethyl) -N-methylamino) -2-methyl-2-propanol, 0.74 g, 4.26 mmol) was added. After stirring for 3 days, the reaction solution was removed under reduced pressure to obtain 0.50 g (yield: 51.25%) of the title compound as a pink liquid.

Elemental Analysis C ₂₇ H ₆₃ N ₆ O ₃ Er {calculated (calculated)}: C, 47.20 (46.10); H, 9.24 (9.54); N, 12.23 (11.53)

FT-IR (cm ^-1 , KBr pellet): υ 2940, 2770, 1460, 1170, 1110, 949, 793, 588, 469 cm ^-1 .

Example 2 Synthesis of Tris [2- (N- (2- (dimethylamino) ethyl) -N-methylamino) epoxy] erbium and [Er (demae) ₃ ]

3.0 g (4.63 mmol) of the compound of formula 5 were dissolved in a 125 mL Schlenk flask containing toluene (70 mL), followed by 2- (N- (2-dimethylamino) ethyl) -N-methylamino]. Ethanol (demaeH, (2- (N- (2- (dimethylamino) ethyl) -N-methylamino) ethanol, 2.04 g, 13.95 mmol) was added and stirred for 3 days. The reaction solution was removed under reduced pressure. This gave 1.42 g (yield: 50.88%) of the title compound as a blue liquid.

Elemental Analysis C ₂₁ H ₅₁ N ₆ O ₃ Er {calculated (calculated)} :: C, 41.83 (41.82); H, 8.53 (9.21); N, 13.94 (12.59)

FT-IR (cm ^-1 , KBr pellet): υ 2940, 2770, 1460, 1130, 1040, 897, 729, 613, 463 cm ^-1 .

As described above, the erbium oxide precursor according to the present invention is not only excellent in thermal stability and volatility by coordinating an oxygen atom and a nitrogen atom ligand to erbium, but also less sensitive to moisture and advantageous in storage, thus providing an excellent oxide film. It can be usefully used as an erbium precursor having a novel ligand for metal organic chemical vapor deposition (MOCVD) or atomic layer deposition (ALD) to be prepared.

Claims (6)

Erbium oxide precursors represented by Formula 1: [Formula 1] Er [OAN (R ³ ) -B-NR ¹ R ² ] ₃ [Wherein A is alkylene of C ₂ -C ₅ ; B is alkylene of C ₁ -C ₄ ; A and B may be further substituted with one or more C ₁ -C ₅ straight or branched alkyl groups; R ¹ , R ² and R ³ independently of one another are H or C ₁ -C ₅ linear or branched alkyl groups.] The method of claim 1, Erbium oxide precursor represented by the following formula (2). [Formula 2] Er [OCR ⁴ R ⁵ (CH ₂ ) _m N (R ³ )-(CH ₂ ) _n NR ¹ R ² ] ₃ [Wherein R ¹ , R ² , R ³ , R ⁴ And R ⁵ is independently of each other H or a C ₁ -C ₅ linear or branched alkyl group, m and n are integers from 1 to 4.] The method of claim 2, Wherein R ¹ , R ² , R ³ , R ⁴ And R ⁵ is independently from each other H, CH ₃ , C ₂ H ₅ , CH (CH ₃ ) ₂ or C (CH ₃ ) ₃ . A method for producing an erbium oxide precursor of formula (1), comprising reacting a compound of formula (5) obtained by reacting an erbium compound of formula (3) with an alkali metal salt compound of formula (4) with an alcohol compound of formula (6): [Formula 1] Er [OAN (R ³ ) -B-NR ¹ R ² ] ₃ [Formula 3] ErCl ₃ [Formula 4] M [N (Si (CH ₃ ) ₃ ) ₂ ] [Formula 5] Er [N (Si (CH ₃ ) ₃ ) ₂ ] ₃ [Formula 6] HO-AN (R ³ ) -B-NR ¹ R ² [In Formula 1, Formula 4 and Formula 6, M is Li, Na or K; A is alkylene of C ₂ -C ₅ ; B is alkylene of C ₁ -C ₄ ; A and B may be further substituted with one or more C ₁ -C ₅ straight or branched alkyl groups; R ¹ , R ² and R ³ independently of one another are H or C ₁ -C ₅ linear or branched alkyl groups.] A method of growing erbium oxide using the erbium oxide precursor according to claim 1. The method of claim 5, Erbium oxide is formed by organometallic chemical vapor deposition (MOCVD) or atomic layer deposition (ALD).

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