KR20110006968A - Novel titanium alkoxide compounds and process for preparing method thereof - Google Patents

Abstract

PURPOSE: A method for preparing titanium alkoxide compound is provided to manufacture thermally stable titanium oxide thin film. CONSTITUTION: A titanium alkoxide compound is denoted by chemical formula 1(Ti(OCR^1R^2R^3)_4). In chemical formula 1, R1 and R2 are independently linear or branched alkyl group of C1-C5; and R3 is linear alkenyl or alkinyl group of C2-C5. A titanium alkoxide compound is prepared by reacting alcohol compound of chemical formula 3(HOCR^1R^2R^3) with titanium amide compound of chemical formula 4(Ti(NR^4R^5)_4). A titanium oxide thin film is manufactured using titanium alkoxide compound as a precursor by MOCVD(metal organic chemical vapor deposition) and ALD(atomic layer deposition).

Description

Novel titanium alkoxide compounds and process for preparing method

The present invention relates to novel titanium alkoxide compounds, and more particularly to titanium alkoxide compounds useful as precursors for the production of titanium oxide thin films and methods for their preparation.

Recently, thin films such as gate insulating films of MOS transistors, dielectric films of capacitors, and the like have been formed using materials having a high-k dielectric. The thin film made of a material having a high dielectric constant can sufficiently reduce the leakage current frequently generated between the gate electrode and the channel or the lower electrode and the upper electrode while maintaining a thin equivalent oxide thickness (EOT). to be.

Examples of the thin film made of a material having a high dielectric constant mainly used include a titanium oxide film (TiO ₂ ), a hafnium oxide film (HfO ₂ ), and the like.

Titanium oxide (Titania, TiO ₂ ) is a material applied in many fields such as dielectric layers, antireflection coatings for optical devices, sensors, and photocatalysts. A method of growing these titania materials is metal organic chemical vapor deposition (MOCVD). This process has the advantages of a simple device, superior layer coverage compared to other techniques, easy control of components, and no difficulty in switching to mass production. Another method is atomic layer deposition (ALD), which has the advantage of allowing self-limiting reactions to grow thin films to a desired thickness. Korean Patent Laid-Open Publication Nos. 10-2006-0013046, 10-2006-0014514 and the like are known as methods for producing titanium oxide films using such chemical vapor deposition and atomic layer deposition. For the manufacture of thin films, it is essential to understand the development and characteristics of the precursors used in the process. The precursors for MOCVD and ALD should be sufficiently high vapor pressure below 200 ° C., thermally stable during heating to vaporize, and sufficiently stable to air and moisture during storage. As an additional requirement, it must be non-toxic or less toxic to itself or to decomposition products, to simplify the synthesis and to lower the cost of the raw materials.

As a precursor for producing titanium oxide, titanium alkoxide is known to be the best material and has been widely used until now. Among them, alkoxide compounds such as titanium tetraisopropoxide (Ti (O ⁱ Pr) ₄ ) are liquid, high vapor pressure, less sensitive to thin film deposition temperature, and bumps on the surface of the thin film to be deposited. It was used as a precursor of titanium oxide at low deposition temperatures (<400 ° C), without causing haze or hazeiness. However, this precursor has an unsaturated Ti (IV) center that is highly reactive to air and moisture. In addition, Ti-O bonds readily decompose at high temperatures, resulting in poor step coverage, which is an advantage of the MOCVD process.

To solve this problem, modified alkoxides with saturated coordination states such as Ti (O ⁱ Pr) ₂ (tmhd) ₂ (tmhd = 2,2,6,6-tetramethyl-3,5-heptanedionate) ) Has been studied. Ti (O ⁱ Pr) ₂ (tmhd) ₂ is known for its high vapor pressure, stability in air and excellent thermal stability. See J.-H. Lee and S.-W. Rhee, J. Electrochem. Soc ., 1999 , 146 , 3783; J.-H. Lee and S.-W. Rhee, Electrochem. Solid-State Lett ., 1999 , 2 , 507]. _{^{Ti (O i Pr) 2 (}} tmhd) by two alkoxide and titanium precursor with two β- diketonates ligand, such as _{^{2 (O i Pr) Ti 2}} (tbaoac) 2 (tbaoac = tert-butylacetoacetate) the The results of studies of depositing thin films using the same have been reported [R. Bhakta, R. Thomas, F. Hipler, HF Bettinger, J. M, P. Ehrhartb, A. Devi, J. Mater. Chem., 2004, 14, 3231.

Also recently, a method of substituting an alkoxide for a functional donor group having two or more donors (eg, dimethylaminoethoxide, dimethylaminopropoxide, etc.) Attempts have been made (K. Szczegot and M. Nowakowska, Polimery ( Warsaw ), 1977 , 22 , 399).

Ti (O ⁱ Pr) ₃ (dmae) and Ti (O ⁱ Pr) ₂ (dmae) ₂ were synthesized by replacing one or two O ⁱ Pr with dmae in 4 coordination Ti (O ⁱ Pr) ₄ . Moisture less sensitive than alkoxides, using these compounds as precursors, a good quality TiO ₂ film was obtained by liquid injection CVD [AC Jones, TJ Leedham, PJ Wright, MJ Crosbie, KA] Fleeting, DJ Otway, P. O'Brien, and ME Pemble, J. Mater. Chem ., 1998 , 8 , 1773].

Ti (dmae) _{4, which} is composed of all four ligands of dmae, is less sensitive to deposition temperature than Ti (O ⁱ Pr) ₂ (tmhd) ₂ and results in no raised or blurry parts. J. -H. Lee, JY Kim, J.-Y. Shim, and S.-W. Rhee, J. Vac. Sci. Technol. A, 1999 , 17 , 3033].

On the other hand, researches for producing titania thin films using ALD have been actively conducted in recent years. The source of titanium is mainly Ti (OiC ₃ H ₇ ) ₄ [M. Ritala, M. Leskel, L. Niinist, and P. Haussalo, Chem. Mater. , 1993 , 5 , 1174; A. Rahtu and M. Ritala, Chem. Vap. Deposition , 2002 , 8 , 21] or Ti (OC ₂ H ₅ ) ₄ [M. Ritala, M. Leskel, and E. Rauhala, Chem. Mater. , 1994 , 6 , 556; J. Aarik, A. Aidla, V. Sammelselg, T. Uustare, M. Ritala, and M. Leskel, Thin Solid Films , 2000 , 370 , 163; A. Rahtu, K. Kukli, and M. Ritala, Chem. Alkoxide compounds such as Mater ., 2001 , 13 , 817] or TiCl ₄ [M. Ritala, M. Leskel, E. Nyknen, P. Soininen, and L. Niinist, Thin Solid Films , 1993 , 225 , 288 ; J. Aarik, A. Aidla, A.-A. Kiisler, T. Uustare, and V. Sammelselg, Thin Solid Films , 1997 , 305 , 270; R. Matero, A. Rahtu, and M. Ritala, Chem. Mater ., 2001 , 13 , 4506] or TiI ₄ [K. Kukli, M. Ritala, M. Schuisky, M. Leskel, T. Sajavaara, J. Keinonen, T. Uustare, and A. H, Chem. Vap. Deposition , 2000 , 6 , 303; K. Kukli, A. Aidla, J. Aarik, M. Schuisky, A. H, M. Ritala, and M. Leskel, Langmuir , 2000 , 16 , 8122]. Add water to the oxygen source.

As described above, titanium compounds known in the related art have disadvantages that materials having a low deposition temperature are sensitive to air or moisture and materials in the air or thermally stable are very low in vapor pressure despite the advantages of the compounds. Therefore, the development of new titanium oxide precursors to increase thermal stability and volatility is significant.

In order to solve the problems of the existing compounds, the present inventors do not cause contamination of carbon or fluorine, increase thermal stability, high volatility, and high reactivity with ozone in the process of forming a titanium oxide thin film. Titanium transition metal oxide precursors have been developed.

The present invention is to solve the problems of the prior art as described above, an object of the present invention is thermally stable to form a high quality titanium oxide thin film and high volatility but not too high reactivity and ozone in the process of forming a titanium oxide thin film The present invention provides a titanium alkoxide compound having a higher reactivity with a conventional material and a method for preparing the same.

The present invention relates to a titanium alkoxide compound which is thermally stable, has high volatility and is not too high in reactivity, and has a higher reactivity with ozone than a conventional material in the process of forming a titanium oxide thin film. To provide.

[Formula 1]

Ti (OCR ¹ R ² R ³ ) ₄

[In Formula 1, R ¹ and R ² are each independently a C ₁ -C ₅ linear or branched alkyl group, R ³ is C ₂ -C ₅ linear alkenyl or alkynyl group.]

,

,

또는

로부터 선택되고, 상기 R³은

,

,

,

,

또는

인 것이 보다 바람직하다. In Formula 1, R ¹ and R ² are independently of each other

,

,

or

Is selected from, and R ³ is

,

,

,

,

or

It is more preferable that is.

Ti (OCR ¹ R ² R ³ ) ₄ of Formula 1 may be specifically exemplified by the following structure, but is not limited thereto, and R ¹ to R ³ of the following structure are the same as defined in Formula 1 above.

Hereinafter, the method for producing a titanium alkoxide compound according to the present invention will be described in more detail.

The titanium alkoxide compound of Chemical Formula 1 according to the present invention may be prepared by reacting a titanium amide compound of Chemical Formula 2 with an alcohol compound of Chemical Formula 3 under a nonpolar solvent as a starting material.

[Formula 2]

Ti (NR ⁴ R ⁵ ) ₄

(3)

HOCR ¹ R ² R ³

The titanium amide compound of Formula 2 may be selectively used from Ti (NMe ₂ ) ₄ , Ti (NEt ₂ ) ₄ or Ti (NEtMe) ₄ , and the alcohol compound of Formula 3 may be selected from HOCCH ₃ CH ₃ C≡CH or HOCCH. _It may optionally be used from ₃ CH ₂ CH ₃ C≡CH, but is not limited thereto.

The reaction scheme is shown in Scheme 1 below.

Scheme 1

Ti (NR ⁴ R ⁵ ) ₄ + 4 HOCR ¹ R ² R ³ ¡Æ Ti (OCR ¹ R ² R ³ ) ₄ + 4 HNR ⁴ R ⁵

[In Formula 2, Formula 3 and Scheme 1, R ¹ , R ² , R ⁴ and R ⁵ are independently of each other a C ₁ -C ₅ linear or branched alkyl group, and R ³ is C ₂ -C ₅ linear alkenyl or alkynyl group.]

The titanium amide compound (Ti (NR ⁴ R ⁵ ) ₄ ) of Chemical Formula 2, which is a starting material in Scheme 1, contains a highly reactive dialkylamido ligand, and thus has a relatively acidic hydrogen as compared to that of a secondary amine. The titanium alkoxide compound (Ti (OCR ¹ R ² R ³ ) ₄ ) of Chemical Formula 1 may be prepared by performing a 4-equivalent substitution reaction with an alcohol compound of 3 (HOCR ¹ R ² R ³ ).

In more detail, Reaction Scheme 1, a non-polar solvent such as hexane, pentane or toluene in which 4 equivalents of the alcohol compound of Formula 3 is dissolved in a non-polar solvent such as hexane, pentane or toluene in which 1 equivalent of the titanium amide compound of Formula 2 is dissolved The compound of formula 1 may be obtained by slowly adding at room temperature and then performing a substitution reaction for 1 to 48 hours and then removing the solvent under reduced pressure.

In addition, the titanium alkoxide compound of Formula 1 As another method of preparing, the titanium halide compound of Formula 4 may be prepared by reacting an alkali metal salt of Formula 5 under an organic solvent.

[Formula 4]

TiX ₄

[Chemical Formula 5]

MOCR ¹ R ² R ³

The titanium halide compound of Formula 4 may be selectively used from TiCl ₄ , TiBr ₄ or TiI ₄ , and the alkali metal salt of Formula 5 may be selectively selected from NaOCCH ₃ CH ₃ C≡CH or NaOCCH ₃ CH ₂ CH ₃ C≡CH. It may be used, but is not limited thereto.

The reaction scheme is shown in Scheme 2 below.

Scheme 2

TiX ₄ + 4 MOCR ¹ R ² R ³ → Ti (OCR ¹ R ² R ³ ) ₄ + 4 MX

[In Formula 4, Formula 5 and Scheme 2, R ¹ and R ² are each independently a C ₁ -C ₅ linear or branched alkyl group, R ³ is C ₂ -C ₅ is a linear alkenyl or alkynyl group, X is Cl, Br or I, and M is Li, Na or K.]

In detail, Reaction Scheme 2, 1 equivalent of the titanium halide compound represented by Chemical Formula 4, and 4 equivalents of the alkali metal salt of Chemical Formula 5 are reacted in an organic solvent such as tetrahydrofuran, toluene, or hexane for 0.5 to 3 hours. After refluxing for 1 to 48 hours, the solvent may be removed under reduced pressure to obtain a compound of Formula 1.

The titanium alkoxide compound represented by the formula (1) is a central metal bonded to oxygen when compared with titanium t-butoxide or titanium isopropoxide by introducing various alkyl groups having different sizes to the carbon at the α-position to the oxygen of the alkoxide. This precursor may exist as a monomer because it impairs steric hindrance to prevent intermolecular interactions with oxygen of these neighboring ligands. Due to these structural properties, the titanium alkoxide compound of Chemical Formula 1 is a stable liquid at room temperature, has high solubility in organic solvents such as pentane, hexane, diethyl ether, tetrahydrofuran, toluene, etc. Since it does not contain an element and is stable at room temperature and is advantageous for storage, a titanium oxide thin film having better quality may be obtained using the titanium alkoxide compound of Chemical Formula 1.

The novel titanium alkoxide compound according to the present invention is a precursor for producing a titanium oxide thin film, and is particularly applicable to metal organic chemical vapor deposition (MOCVD) or atomic layer deposition (ALD) processes widely used in semiconductor manufacturing processes.

The novel titanium alkoxide compound, which is a Group 4 transition metal oxide precursor according to the present invention, is thermally sufficiently stable, is advantageous for storage, and has high reactivity with ozone. It can apply suitably to vapor deposition (MOCVD) or atomic layer deposition (ALD).

Hereinafter, the present invention will be described in more detail with reference to Examples, which are intended only for understanding the constitution and effects of the present invention, and are not intended to limit the scope of the present invention.

[Example]

All experiments were performed in an inert argon or nitrogen atmosphere using a glove box or Schlenk line. The structures and physical properties of the reaction products obtained in Examples 1 and 2, respectively, were analyzed by ¹ H nuclear magnetic resonance (NMR), carbon atom nuclear magnetic resonance ( ¹³ C NMR), and elemental analysis. , EA), mass spectroscopy, thermogravimetric analysis / differential thermal analysis (TGA / DTA).

Example 1 Synthesis of Tetrakis (3-methyl-1-pentin-3-oxy) titanium (IV) [Ti (mpy) ₄ ]

Tetrakisdimethylamidotitanium (IV) (5 g, 22 mmol) was dissolved in a flame dried 125 mL Schlenk flask containing hexane (50 mL). To this solution was added slowly a solution of hexane (30 mL) in which mpyH (3-methylpent-1-yn-3-ol) (9.85 g, 100 mmol) was dissolved and stirred for 12 hours. The solvent was removed under reduced pressure and purified under reduced pressure at 130 ° C./10 ⁻² torr to obtain 8.5 g of the title compound Ti (mpy) _{4 as} a pale yellow liquid (yield: 88.5%).

¹ H NMR (C ₆ D ₆ , 300.13 MHz): δ 1.20 (t, 12H, J = 7.2 Hz, CCH ₂ C H ₃ ), 1.69 (s, 12H, CC H ₃ ), 1.88 (m, 8H, J = 7.2 Hz, CC H ₂ CH ₃ ), 2.11 (s, 4H, CC H ).

¹³ C { ¹ H} NMR (C ₆ D ₆ , 75.03 MHz): δ 9.57 (CCH ₂ C H ₃ ), 31.4 (C C H ₃ ), 38.3 (C C H ₂ CH ₃ ), 70.9 ( C CH ₂ CH ₃ ), 80.3 (C C H), 88.1 ( C CH).

EA for C ₂₄ H ₃₆ O ₄ Ti Found (Calcd.) C; 66.32 (66.05), H; 8.30 (8.31)

Example 2 Synthesis of Tetrakis (3-methyl-1-pentin-3-oxy) titanium (IV) [Ti (mpy) ₄ ]

Titanium (IV) chloride (2.85 g, 15 mmol) was dissolved in a flame-dried 125 mL Schlenk flask containing hexane (50 mL). To this solution was added slowly a solution of hexane (30 mL) dissolved Na (mpy) (mpy: 3-methylpent-1-yn-3-oxy) (8.1 g, 67.5 mmol) and stirred at room temperature for 1 hour and then 12 hours. During the reflux reaction. The solvent was removed under reduced pressure and purified under reduced pressure at 130 ° C./10 ⁻² torr to obtain 5.3 g of the title compound Ti (mpy) _{4 as} a pale yellow liquid (yield: 81.5%).

¹ H NMR (C ₆ D ₆ , 300.13 MHz): δ 1.20 (t, 12H, J = 7.2 Hz, CCH ₂ C H ₃ ), 1.69 (s, 12H, CC H ₃ ), 1.88 (m, 8H, J = 7.2 Hz, CC H ₂ CH ₃ ), 2.11 (s, 4H, CC H ).

¹³ C { ¹ H} NMR (C ₆ D ₆ , 75.03 MHz): δ 9.57 (CCH ₂ C H ₃ ), 31.4 (C C H ₃ ), 38.3 (C C H ₂ CH ₃ ), 70.9 ( C CH ₂ CH ₃ ), 80.3 (C C H), 88.1 ( C CH).

Example 3 Synthesis of Tetrakis (2-methyl-3-butyn-2-oxy) titanium (IV) [Ti (mby) ₄ ]

Tetrakisdimethylamidotitanium (IV) (5 g, 22 mmol) was dissolved in a flame dried 125 mL Schlenk flask containing hexane (50 mL). To this solution was slowly added a solution of mbyH (2-methylbut-3-yn-2-ol) (8.4 g, 100 mmol) in hexane (30 mL) and stirred for 12 hours. The solvent was removed under reduced pressure and purified under reduced pressure at 110 ° C / 10 ^-2 torr to obtain 7.4 g of the title compound Ti (mby) _{4 as} a yellow liquid (yield: 89.2%).

¹ H NMR (C ₆ D ₆ , 300.13 MHz): δ 1.64 (s, 24H, C (C H ₃ ) ₂ ), 2.14 (s, 4H, CC H ).

¹³ C { ¹ H} NMR (C ₆ D ₆ , 75.03 MHz): δ 33.2 (C ( C H ₃ ) ₂ ), 70.0 ( C (CH ₃ ) ₂ ), 76.3 (C C H), 89.2 ( C CH ).

EA for C ₂₀ H ₂₈ O ₄ Ti Found (Calcd.) C; 62.97 (63.12), H; 7.93 (7.42)

1 and 2 show nuclear and magnetic resonance spectra of hydrogen and carbon atoms of Ti (mpy) ₄ (mpy: 3-methylpent-1-yn-3-oxy), and an ethyl group of Ti (NEtMe) ₄ used as a starting material. It was confirmed that the peaks of the and methyl groups disappeared and the peaks of the mpyH (3-methylpent-1-yn-3-ol) ligand used as reaction materials appeared.

3 shows Ti (mpy) ₄ Infrared spectra showing the hydroxy group peaks of the mpyH (3-methylpent-1-yn-3-ol) ligand used as the reactant and disappearing at 636 cm ^-1 . It was confirmed that the combination of titanium and oxygen appeared.

4 shows a TG / DTA graph of Ti (mpy) ₄ (10 ° C./min to 600 ° C., 100 cc / min N ₂ purge), where a mass reduction of about 5% occurred at 50 to 130 ° C. It was confirmed that a sharp mass reduction occurred at 130 ℃. In addition, a mass loss of 92% or more was observed at 240 ° C, and residual material was about 3%. The TGA graph shows that T _1/2 (the temperature at which the weight of the sample at half the original weight at weight loss with temperature) is 203 ° C.

5 and 6 show nuclear and magnetic resonance spectra of hydrogen and carbon atoms of Ti (mby) ₄ (mby: 2-methylbut-3-yn-2-oxy), and an ethyl group of Ti (NEtMe) ₄ used as a starting material. The peaks of and the methyl group disappeared and the peaks of the mbyH (2-methylbut-3-yn-2-ol) ligand used as a reaction material were observed.

7 shows Ti (mby) ₄ Illustrates the IR spectrum, mbyH used as reactant (2-methylbut-3-yn -2-ol) do not have a hydroxyl group peaks of the ligand is at 630 cm ^-1 It was confirmed that the combination of titanium and oxygen appeared.

8 shows a TG / DTA graph of Ti (mby) ₄ (10 ° C./min to 600 ° C., 100 cc / min N ₂ purge), where a mass reduction of about 3% occurred at 50 to 120 ° C., and 120 It was confirmed that a sharp mass reduction occurred at ℃. In addition, a mass loss of 95% or more was observed at 210 ° C, and residual material was about 2%. TGA graph shows that T _1/2 is 180 ° C.

1 is a hydrogen atom nuclear magnetic resonance ⁽¹ H NMR) spectrum of a Ti (mpy) ₄ prepared in Example 1 according to the invention, Figure 2 is a _four by Ti (mpy) prepared in Example 1 according to the invention Carbon atom nuclear magnetic resonance ( ¹³ C NMR) spectrum of, Figure 3 is an infrared (IR) spectrum of Ti (mpy) ₄ prepared in Example 1 according to the present invention, Figure 4 is a first embodiment according to the present invention Thermal analysis (TG / DTA) graph of Ti (mpy) ₄ prepared in Fig. 5 is a hydrogen atom nuclear magnetic resonance ( ¹ H NMR) spectrum of Ti (mby) ₄ prepared in Example 3 according to the present invention 6 is a carbon atom nuclear magnetic resonance ( ¹³ C NMR) spectrum of Ti (mby) ₄ prepared in Example 3 according to the present invention, and FIG. 7 is Ti (mby) prepared in Example 3 according to the present invention. Infrared (IR) spectrum of ₄ , Figure 8 is a thermal analysis (TG / DTA) graph of Ti (mby) ₄ prepared in Example 3 according to the present invention.

Claims (6)

Titanium alkoxide compound represented by the following formula (1). [Formula 1] Ti (OCR ¹ R ² R ³ ) ₄ [In Formula 1, R ¹ and R ² are each independently a C ₁ -C ₅ linear or branched alkyl group, R ³ is C ₂ -C ₅ linear alkenyl or alkynyl group.] The method of claim 1, R ¹ and R ² are independently of each other

,

,

or

Is selected from, and R ³ is

,

,

,

,

or

Titanium alkoxide compound, characterized in that selected from. A method for preparing a titanium alkoxide compound of formula 1 according to claim 1 by reacting a titanium amide compound of formula 2 with an alcohol compound of formula 3 below. [Formula 2] Ti (NR ⁴ R ⁵ ) ₄ (3) HOCR ¹ R ² R ³ [In Formula 2 and Formula 3, R ¹ , R ² , R ⁴ and R ⁵ are independently of each other a C ₁ -C ₅ linear or branched alkyl group, and R ³ is C ₂ -C ₅ linear alkenyl or alkynyl group.] A method for preparing a titanium alkoxide compound of formula 1 according to claim 1 by reacting a titanium halide compound of formula 4 with an alkali metal salt of formula 5 below. [Formula 4] TiX ₄ [Chemical Formula 5] MOCR ¹ R ² R ³ [In Formulas 4 and 5, R ¹ and R ² are each independently a C ₁ -C ₅ linear or branched alkyl group, R ³ is C ₂ -C ₅ is a linear alkenyl or alkynyl group, X is Cl, Br or I, and M is Li, Na or K.] A method for producing a titanium oxide thin film, comprising using the titanium alkoxide compound of any one of claims 1 or 2 as a precursor. The method of claim 5, The titanium oxide thin film is formed by chemical vapor deposition (MOCVD) or atomic layer deposition (ALD).

Images