JP6655838B2 - Mg-based material forming material, Mg-based material forming method, and novel compound - Google Patents

Description

  The present invention relates to a technology for forming a Mg-based material.

  Materials (for example, films) such as magnesium metal, magnesium alloy, magnesium oxide, magnesium nitride, and magnesium boride are required in various fields. The field is the field of semiconductors. Mg is used, for example, as a doping material for an active layer of gallium nitride for a blue LED. The field is the field of magnetic materials (eg, magnetoresistive memories). MgO is indispensable, for example, as a material for a next-generation memory (for example, MRAM). The field is that of alloys (eg, functional alloys). The MgTi alloy film has a high possibility as a light control mirror. Said field is the field of energy storage. The field is the field of superconductivity.

An Mg-based film (for example, a Mg film, a MgO film, a Mg ₃ N ₂ film, a MgB ₂ film, etc.) is formed by a chemical vapor deposition method (CVD method) or an atomic layer controlled growth method (ALD method). In this case, as a raw material, for example, a β-diketonate magnesium complex, a cyclopentadienyl-based magnesium complex, and the like have been proposed.

  When a β-diketonatomagnesium complex having O (oxygen atom) is used as a raw material compound, O has penetrated the inside of the film formed. For this reason, when the film is an MgO film, no major problem is expected to occur. However, when the target film is a film originally having no oxygen (O), there is a concern about a problem.

A cyclopentadienyl-based magnesium complex (for example, bis (cyclopentadienyl) magnesium; MgCp ₂ ) does not have O (oxygen atom). Therefore, when the complex is used, it seems that O basically does not enter the inside of the film. However, the cyclopentadienyl-based magnesium complex has a high decomposition temperature. Therefore, there is a concern that C (carbon atom) may enter the inside of the film.

As O Mg complex without a (an oxygen ^{_{atom), Mg 2 (μ-NPr}} i 2) 2 [(Pr i N) 2 CNPr i 2] 2 has been proposed (Non-Patent Document 1). ^{_{Mg 2 (μ-NPr i 2}} ) 2 [(Pr i N) 2 CNPr i 2] 2 solid (mp: 120 ° C.) is. Therefore, there is a concern about the same problem as when MgCp ₂ is used.

Non-Patent Document 1 proposes an adduct of Mg (Pr ⁱ NCEtNPr ⁱ ) ₂ (thf) ₂ = bis (N, N′-diisopropylpropionamidinate) magnesium (thf). However, this complex has O (oxygen atom) due to thf (tetrahydrofuran). Therefore, there is a concern about the same problem as when the β-diketonatomagnesium complex is used. The compound is a solid (melting point: decomposed at 290 ° C.). Therefore, there is a concern about the same problem as when MgCp ₂ is used.

J. Chem. Soc., Dalton Trans., 1997, pp957-963.

  High-purity Mg is difficult to obtain. At present, no magnesium compound as a distillable liquid (at 25 ° C. and 1 atm) capable of obtaining high-purity Mg has been proposed. For this reason, a liquid Mg complex that can be distilled has been demanded.

  The problem to be solved by the present invention is to solve the above problems. For example, to provide a liquid Mg complex. Another object of the present invention is to provide a technique that can easily form a high-quality Mg-based material (the material is, for example, a film, but is not limited to a film).

The study for solving the above-mentioned problem has been earnestly promoted.
As a result, liquid bis (N, N′-diisopropylpropionamidinate) magnesium {Mg [i-C ₃ H ₇ NC (C ₂ H ₅ ) Ni-C ₃ H ₇ ] ₂ } was used as a raw material, It has been found that a high-quality Mg-based material can be formed by the CVD method (or the ALD method).

  Furthermore, it has been found that the compound can be synthesized at low cost using, for example, N, N'-diisopropylcarbodiimide as a raw material.

And, bis (N, N'-diisopropyl propionamide amidinate) magnesium _{{Mg [i-C 3 H} 7 NC (C 2 H 5) N-i-C 3 H 7] 2} 1 a liquid (25 ° C. Pressure conditions). The Mg compound was obtained in a high purity by a simple distillation operation. This means that when the compound is used, a high-quality film can be obtained by a CVD method (or an ALD method).

  The present invention has been achieved based on the above findings.

The present invention
We propose a novel compound characterized by being bis (N, N'-diisopropylpropionamidinate) magnesium.

The present invention
We propose a novel compound characterized by the fact that it is bis (N, N′-diisopropylpropionamidinate) magnesium liquid (under 25 ° C. and 1 atm).

The present invention
A material for forming a Mg-based material,
A Mg-based material forming material characterized by having bis (N, N′-diisopropylpropionamidinate) magnesium is proposed.

The present invention
A material for forming a Mg-based material,
A Mg-based material forming material characterized by having bis (N, N′-diisopropylpropionamidinate) magnesium in liquid (25 ° C. and 1 atm) is proposed.

The present invention proposes the Mg-based material forming material, preferably further comprising a solvent.

  The present invention provides the Mg-based material-forming material, wherein the solvent is preferably one or two or more selected from the group of hydrocarbon-based compounds. suggest.

  The present invention proposes the Mg-based material forming material, wherein the solvent is preferably N, N'-diisopropylpropionamidine.

The present invention
Transporting the Mg-based material forming material to a chamber;
Providing a Mg-based material on a substrate by decomposing bis (N, N′-diisopropylpropionamidinate) magnesium transported to the chamber.

  Bis (N, N'-diisopropylpropionamidinate) magnesium is a liquid (at 25 ° C. and 1 atmosphere). The compound has no O (oxygen atom). The compound was obtained simply and at low cost from N, N'-diisopropylcarbodiimide as a raw material. Moreover, a high-purity product was obtained by a simple distillation operation.

  The compound is easy to vaporize. The gas of the compound can be stably transported. Good film formation efficiency. Therefore, a high-quality material (for example, a film) was obtained at low cost by means such as a CVD method (or an ALD method). For example, a high quality metal Mg film was formed. Alternatively, a high quality Mg alloy film was formed. Even if O was contained in the formed film, the O content was extremely small.

Schematic diagram of CVD equipment Schematic diagram of CVD equipment

  The first invention is a novel compound. The compound is bis (N, N'-diisopropylpropionamidinate) magnesium. The compound is liquid (under 25 ° C. and 1 atm).

A second invention is an Mg-based material forming material. The Mg-based material is a Mg-based film. The material is not limited to a film. For example, it may be thicker than the concept of a film. The Mg-based film is, for example, a metal Mg film. The Mg-based film is, for example, a Mg metal alloy film. The Mg-based film is a MgX (X is a nonmetallic element (for example, N, B or the like (particularly, an element other than O)) or a semiconductor element) film. The Mg-based material has bis (N, N′-diisopropylpropionamidinate) magnesium. Since “has”, the Mg-based material forming material may be only bis (N, N′-diisopropylpropionamidinate) magnesium. However, it may have (comprise) other compounds. In carrying out the CVD method (or the ALD method), a solvent is often used for transporting a target compound. Therefore, the Mg-based material forming material preferably further contains (including) a solvent. The solvent is preferably one kind or two or more kinds selected from the group of hydrocarbon compounds (which may be any of linear, branched and cyclic types). The hydrocarbon compound is preferably a hydrocarbon compound having 5 to 40 carbon atoms. More preferred are hydrocarbon compounds having 5 to 21 carbon atoms. For example, pentane _{(C 5 H 12),} hexane _{(C 6 H 14),} heptane _{(C 7 H 16),} octane _{(C 8 H 18),} nonane _{(C 9 H 20),} decane _{(C 10 H} 22), Undecane (C ₁₁ H ₂₄ ), dodecane (C ₁₂ H ₂₆ ), tridecane (C ₁₃ H ₂₈ ), tetradecane (C ₁₄ H ₃₀ ), pentadecane (C ₁₅ H ₃₂ ), hexadecane (C ₁₆ H ₃₄ ), heptadecane ( C ₁₇ H ₃₆ ), octadecane (C ₁₈ H ₃₈ ), nonadecane (C ₁₉ H ₄₀ ), icosane (C ₂₀ H ₄₂ ), and henycosan (C ₂₁ H ₄₄ ). Among them, preferred are hydrocarbons having 5 to 10 carbon atoms. This is because the decomposition temperature is high and stable. Furthermore, it is inexpensive. The solvent is preferably N, N'-diisopropylpropionamidine.

  The third invention is a method of forming a Mg-based material. For example, this is a method in which a Mg-based material (Mg-based film) is formed by a CVD method (or an ALD method). The method includes a step of transporting the Mg-based material to a chamber. The method includes a step of providing an Mg-based material on a substrate by decomposition of bis (N, N'-diisopropylpropionamidinate) magnesium transported to the chamber. In the method, the Mg-based material is provided on a substrate by transporting the Mg-based material to a chamber and decomposing bis (N, N′-diisopropylpropionamidinate) magnesium transported to the chamber. It is a way to be. The chamber is, for example, a film formation chamber (also referred to as a decomposition chamber or a reaction chamber).

  The Mg-based material (for example, a film) obtained as described above had very few O and C components as impurities. Impurity components such as O and C could not be detected by XPS (X-ray photoelectron spectroscopy). That is, the purity was high.

  Further, troubles in the film formation process hardly occur. For example, the raw material (x (g)) was vaporized and decomposed to form a film. After 0.7 × (g) of the raw material was consumed, the film forming operation was stopped. The inside of a pipe connecting the raw material container and the film forming chamber was observed. No blockage inside the pipe (blockage due to solidification of the raw material) was observed.

The non-patent document does not disclose the present invention. The non-patent document does not disclose bis (N, N′-diisopropylpropionamidinate) magnesium. Bis (N, N′-diisopropylpropionamidinate) magnesium is not disclosed in Scheme 2 (958 page) of the non-patent document. _{^{Mg [(Pr i N) 2}} CNPr i 2] disclosure of ₂ (thf) is not only there. This compound is a solid (melting point: 144 ° C.). The fact that bis (N, N′-diisopropylpropionamidinate) magnesium is a liquid could hardly be imagined from the above-mentioned non-patent document. Furthermore, the non-patent document does not disclose a film forming technique (for example, a CVD method or an ALD method). Therefore, the present inventor is convinced that the present invention could not be easily invented from the non-patent document.

  Hereinafter, specific examples will be given. However, the present invention is not limited only to the following examples. Various modifications and applications are also included in the present invention as long as the features of the present invention are not significantly impaired.

[Synthesis method I of bis (N, N'-diisopropylpropionamidinate) magnesium]
The reaction was performed under an inert gas atmosphere. 0.5 mol of N, N'-diisopropylcarbodiimide was dissolved in 1000 ml of diethyl ether. The solution was cooled to -40C. A benzene solution containing 0.5 mol of ethyllithium was slowly dropped into the solution. Thereafter, stirring was performed at room temperature for 4 hours. This reaction mixture was gradually added dropwise to a solution of 0.25 mol of magnesium bromide (MgBr ₂ ) suspended in 600 ml of diethyl ether. Thereafter, stirring was performed for 24 hours. After evaporation of the solvent, 1500 ml of normal hexane were added. Insolubles were filtered. After distilling off the solvent, distillation under reduced pressure (0.1 torr) was performed. The boiling point was 80 ° C. Bis (N, N′-diisopropylpropionamidinate) magnesium was obtained in a liquid state (at 25 ° C. and 1 atm) with a yield of 78%.
The purity of the obtained bis (N, N'-diisopropylpropionamidinate) magnesium was high. The analysis value (unit: μg / g) by metal impurity analysis (ICP-AES) was as follows. Si <10, Na <5, Fe <5, Zn <5, Ti <5, Cu <5, Cr <5, Cd <5, Mn <5, Co <5, Ni <5 (all below the detection limit )

[Formation of Mg material]
[Example 1]
FIG. 1 is a schematic diagram of a film forming apparatus. In FIG. 1, reference numeral 1 denotes a raw material container. A substrate heater 2 holds and heats the substrate. Reference numeral 3 denotes a film forming chamber (decomposition reaction furnace). 4 is a substrate. 5 is a flow controller. 6 is a shower head. Reference numeral 7 denotes a carrier gas (hydrogen or an inert gas such as Ar or N ₂ ). Reference numeral 10 denotes an additive gas (for example, an inert gas such as Ar or N ₂ or a reducing gas such as H ₂ or NH ₃ ) introduced into the film forming chamber 3 during film formation.
The apparatus shown in FIG. 1 was used to perform a film forming operation. First, bis (N, N′-diisopropylpropionamidinate) magnesium was placed in the raw material container 1. The raw material container 1 was heated to 90 ° C. by a heater (not shown). Hydrogen gas (carrier gas) was supplied at a rate of 20 ml / min, and bubbling was performed. Thereby, bis (N, N′-diisopropylpropionamidinate) magnesium was led into the film forming chamber 3 together with the hydrogen gas. The wall of the film forming chamber 3, the shower head 6, and the piping from the raw material container 1 to the shower head 6 are heated to 110 ° C. The inside of the film forming chamber 3 was evacuated by a pump (not shown). The inside of the film forming chamber 3 is adjusted to a desired pressure (for example, 1 kPa) by a pressure adjusting valve (not shown) provided between the film forming chamber 3 and the pump. The substrate 4 is heated to 280 ° C. by the substrate heater 2. After 10 minutes, a film (metallic Mg thin film) was formed on the substrate 4.
The film formed as described above had excellent in-plane uniformity. The film was examined by XPS. As a result, the amounts of C and O in the film were below the detection limit.

[Example 2]
The operation was performed under the same conditions as in Example 1 (however, the operation time was 48 hours). As a result, a thick Mg material was obtained.
The purity of the obtained Mg was high. The analysis value (unit: μg / g) by metal impurity analysis (ICP-AES) was as follows. Si <10, Na <5, Fe <5, Zn <5, Ti <5, Cu <5, Cr <5, Cd <5, Mn <5, Co <5, Ni <5 (all below the detection limit )

[Example 3]
The apparatus of FIG. 1 was used. The operation was performed in the same manner as in Example 1 except that 10 sccm of Ar gas was used as the carrier gas 7, and 40 sccm of Ar gas, 20 sccm of NH ₃ gas, and 80 sccm of H ₂ gas were used as the deposition gas 10. . The film formation time was 30 minutes.
The film formed as described above was a metal Mg film. The film was excellent in in-plane uniformity. The film was examined by XPS. As a result, the amounts of C and O in the film were below the detection limit.

[Example 4]
The apparatus of FIG. 1 was used. The same operation as in Example 1 was performed, except that 25 sccm of Ar gas was used as the carrier gas 7, and 100 sccm of Ar gas, 500 sccm of NH ₃ gas, and 50 sccm of H ₂ gas were used as the additional gas 10 during film formation. . The film formation time was 20 minutes.
The film formed as described above was a metal Mg film. The film was excellent in in-plane uniformity. The film was examined by XPS. As a result, the amounts of C and O in the film were below the detection limit.

[Example 5]
FIG. 2 is a schematic diagram of a film forming apparatus. In FIG. 2, reference numeral 1 denotes a raw material container. 2 is a substrate heater. Reference numeral 3 denotes a film forming chamber. 4 is a substrate. 6 is a shower head. 8 is a vaporizer. Reference numeral 9 denotes a raw material feed gas (for example, an inert gas such as He or Ar) for feeding the raw material from the raw material container 1 to the vaporizer 8. Reference numeral 10 denotes an additive gas (for example, an inert gas such as Ar or N ₂ or a reducing gas such as H ₂ or NH ₃ ) introduced into the film forming chamber 3 during the film formation. Reference numeral 11 denotes a pressure controller for the raw material pressure gas 9. Reference numeral 12 denotes a liquid flow controller. The liquid flow controller 12 controls the flow rate of the raw material liquid under pressure to the vaporizer 8.
The film forming operation was performed using the apparatus of FIG. First, a decane solution of bis (N, N′-diisopropylpropionamidinate) magnesium was placed in the raw material container 1. N ₂ gas was used as the raw material pumping gas 9, and the pressure was adjusted to 0.1 MPa by the raw material pumping gas pressure controller 11. The liquid flow controller 12 adjusted the decane solution of bis (N, N'-diisopropylpropionamidinate) magnesium to be 0.1 mg / min and pumped it. Thus, the decane solution of bis (N, N′-diisopropylpropionamidinate) magnesium was sent to the vaporizer 8. The bis (N, N′-diisopropylpropionamidinate) magnesium sent to the vaporizer 8 was led into the film forming chamber 3 together with Ar gas of 50 sccm as a carrier gas. Ar gas 40 sccm, NH ₃ gas 20 sccm, and H ₂ gas 80 sccm were also supplied into the film formation chamber 3 as the addition gas 10 during film formation. The wall of the film forming chamber 3, the shower head 6, and the piping from the raw material container 1 to the shower head 6 are heated to 110 ° C. The inside of the film forming chamber 3 was evacuated by a pump (not shown). The pressure is adjusted to a desired pressure (for example, 1 kPa) by a pressure adjusting valve (not shown) provided between the film forming chamber 3 and the pump. The substrate 4 is heated to 290 ° C. by the substrate heater 2. A film (metallic Mg thin film) was formed on the substrate 4.
The film formed as described above had excellent in-plane uniformity. The film was examined by XPS. As a result, the amounts of C and O in the film were below the detection limit.

[Example 6]
In Example 5, instead of decane _{(C 10 H 22), N} , except that N'- diisopropyl propionamidine was used, was conducted in the same manner. A film (metallic Mg thin film) was formed on the substrate 4.
The film formed as described above had excellent in-plane uniformity. The film was examined by XPS. As a result, the amounts of C and O in the film were below the detection limit.

[Formation of Mg nitride material]
[Example 7]
The apparatus shown in FIG. 1 was used to perform a film forming operation. First, bis (N, N′-diisopropylpropionamidinate) magnesium was placed in the raw material container 1. The raw material container 1 was heated to 90 ° C. by a heater (not shown). Nitrogen gas (carrier gas) was supplied at a rate of 20 ml / min, and bubbling was performed. Thereby, bis (N, N′-diisopropylpropionamidinate) magnesium was led into the film forming chamber 3 together with the nitrogen gas. The wall of the film forming chamber 3, the shower head 6, and the piping from the raw material container 1 to the shower head 6 are heated to 110 ° C. An NH ₃ gas of 40 sccm was supplied as the additional gas 10 during the film formation. The inside of the film forming chamber 3 was evacuated by a pump (not shown). The inside of the film forming chamber 3 is adjusted to a desired pressure (for example, 1 kPa) by a pressure adjusting valve (not shown) provided between the film forming chamber 3 and the pump. The substrate 4 is heated to 550 ° C. by the substrate heater 2. After 10 minutes, a film (Mg nitride thin film) was formed on the substrate 4.
The film formed as described above had excellent in-plane uniformity. The film was examined by XPS. As a result, the amounts of C and O in the film were below the detection limit.

DESCRIPTION OF SYMBOLS 1 Raw material container 2 Substrate heater 3 Film forming chamber 4 Substrate 5 Flow rate controller 6 Shower head 7 Carrier gas 8 Vaporizer 9 Raw material feed gas 10 Additive gas for film formation 11 Raw material pressure feed gas pressure controller 12 Liquid flow controller

Claims (6)

A material for obtaining a Mg-based material (Mg-based material is any of Mg metal, Mg metal alloy, and MgX (X is a nonmetallic element or a semiconductor element)) ;
A material having bis (N, N′-diisopropylpropionamidinate) magnesium. The material of claim 1 further comprising a solvent. 3. The material according to claim 2, wherein the solvent is one or more selected from the group of hydrocarbon compounds. 3. The material of claim 2 wherein the solvent is N, N'-diisopropylpropionamidine. Transporting the material according to any one of claims 1 to 4 to a chamber;
Decomposition of bis (N, N'-diisopropylpropionamidinate) magnesium transported to the chamber causes Mg-based (Mg-based is Mg metal, Mg metal alloy, MgX (X is a non-metal element or semiconductor) Element), wherein a material is provided.   A novel compound which is bis (N, N'-diisopropylpropionamidinate) magnesium which is liquid at 25C.

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