JP4738775B2 - Raw material solution for CVD used for manufacturing a lanthanide-based metal-containing thin film and a method for manufacturing a thin film using the same - Google Patents

Description

  The present invention relates to a CVD raw material for a thin film used when a thin film containing a lanthanide-based metal is produced by a chemical vapor deposition (CVD) method, and a thin film obtained using the same. Specifically, the present invention relates to a CVD raw material for a thin film that can stably obtain a lanthanide-based metal-containing thin film with a small amount of use in a solution vaporization CVD method.

In general, as a raw material vapor supply method for thin film formation by CVD, in the case of a raw material that is liquid at room temperature, such as trimethylgallium (GaAs thin film raw material) or tetraethoxysilane (SiO ₂ thin film raw material), a carrier gas is bubbled through the raw material. A bubbling method in which raw material vapor is accompanied to a film forming chamber is performed. In the case of bubbling, the raw material vapor is generated at a saturated vapor pressure (which depends only on the temperature), so that the raw material vapor can be stably supplied by controlling the temperature.
On the other hand, when the raw material is solid; sublimation method in which raw material vapor is generated by sublimation; the raw material is dissolved in an organic solvent such as tetrahydrofuran, butyl acetate, and toluene at a constant concentration, and the resulting solution is vaporized at high temperature while controlling the flow rate. A solution vaporization method is generally used in which a constant amount of raw material evaporation can be obtained by sending the solution into a room and vaporizing the entire amount.

As a thin film material, a specific metal compound typified by a metal complex such as β-diketone dipivaloylmethane (DPM) is (1) generally high in thermal stability and up to a certain temperature even in the presence of oxygen. (2) Oxide superconductors and ferroelectrics (YBa ₂ Cu ₃ O _y , Bi ₂ Sr ₂ Ca ₂ Cu ₃ O _y , SrBi ₂ Ta ₂ O _9, etc.) are alkaline. Earth metals ( Ca , Sr, Ba, etc.) are contained, and these compounds satisfy the vaporization property, thermal stability, and stability in the presence of oxygen required by the CVD method as those containing alkaline earth metals; It is now widely used. However, since these metal compounds generally have a high melting point, the raw material cannot be vaporized by the bubbling method. In the case of the sublimation method, (1) it is difficult to obtain saturated vapor, and (2) these metal compounds continue to be heated. (3) The amount of steam generated is likely to change depending on the amount of filling in the raw material container or the remaining amount of raw material in use, maintaining a constant raw material evaporation amount and the thin film obtained There was a drawback that it was difficult to control the composition. In particular, for alkaline earth metal complexes with poor vaporization, (4) When heated at a high temperature to increase vaporization efficiency, the raw materials are transported while being thermally decomposed, resulting in poor film crystallinity. (5) If the vaporization rate is reduced and the vapor deposition time is lengthened, the material deteriorates with time and the vaporization property decreases, so that the composition in the thickness direction of the formed film becomes inhomogeneous. There was a problem that would become. For this reason, the solution vaporization method has become the current mainstream for the production of multi-component complex oxide thin films.

  As multi-component complex oxide thin films that have been actively studied in recent years, for example, bismuth lanthanum titanate (BLT) and bismuth neodymium titanate (BNT) for capacitor films of ferroelectric memory (FeRAM) and as electrode films Lanthanum nickelate (LNO) and the like. As a compound containing a lanthanide metal used as a CVD raw material for producing BLT, BNT thin films and LNO thin films by the CVD solution vaporization method, the use of dipivaloylmethanato (DPM) has been studied so far. ) Complexes, 2,2,6,6-tetramethyl-3,5-octanedionate (TMOD) complexes, and diisobutyrylmethanato (DIBM) complexes.

Generally, the activation energy for decomposing a raw material compound to change to a metal, an oxide, or the like differs depending on the raw material compound, and therefore, the supply ratio of each raw material rarely matches the composition ratio of the film. In the case of a lanthanide-based metal, this tendency becomes remarkably remarkable. By using the β-diketone lanthanide complex, a metal other than the lanthanide-based metal and the lanthanide-based metal, such as a BLT, BNT film, or LNO film, is obtained by a solution vaporization CVD method. When the multicomponent composite oxide thin film contained was produced, even if each raw material was supplied at the same ratio as the metal composition of the target film, almost no lanthanide metal was introduced into the film. For example, when La (DPM) ₃ , which is a β-diketone lanthanum complex, is used in the production of a BLT film, the same ratio as the desired film composition (for example, Bi: La: Ti = 3.25: 0.75: 3) When the mixed solution is used, lanthanum is present in the obtained film only at 1/10 or less of the desired film composition.

In order to obtain a desired film composition in such a case, usually two methods are conceivable. The first is to increase the ratio in the raw material solution of a metal compound (lanthanum compound in the case of BLT) that is difficult to be introduced into the film, and the second is a substance that is likely to decompose the metal raw compound that is difficult to be introduced into the film. Is to replace it.
However, when the BLT film is produced by the first method, the lanthanide metal actually introduced into the film is 1/3 of the desired film composition even if the ratio of the lanthanum complex in the raw material solution is 10 times the desired film composition. It was the following. Moreover, the use of a second La as a method (DPM) ₃ in place of La (DPM) ₃ from easily decomposed La (TMOD) _3, lanthanum in the resulting film, La (DPM) ₃ It was 1/10 or less of the desired film | membrane composition similarly to the case where was used.
As described above, β-diketone-based lanthanide complexes have extremely low conversion efficiency (ratio of the amount deposited on the film with respect to the amount of raw material supplied), so a multi-component complex oxide thin film containing a lanthanide-based metal can be used. When manufactured, it was difficult to introduce a lanthanide metal into the thin film.

On the other hand, many CVD raw material compounds in which the central metal is shielded by a neutral ligand have been disclosed in Patent Documents 1 to 5 and so on. However, they prevent reactions between different types of raw material compounds such as ligand exchange, resulting in precipitation in solution or clogging of pipes due to solid precipitation in the gas phase. The purpose is to prevent the deterioration of the raw material solution over time by preventing or preventing the vapor pressure from increasing or stabilizing, or by suppressing the reaction with other substances such as moisture in the solution. As a neutral ligand was added.
In order to improve the conversion efficiency into a film, it is common to select a material that is easily decomposed, and it is not usually conceived to select a stabilized metal compound that is difficult to decompose. Furthermore, β-diketone lanthanide complexes are stable materials that do not easily change over time without the addition of neutral ligands, and the addition of neutral ligands reduces the vapor pressure. As a CVD material, it has never been actively used to improve the conversion efficiency into a film.
Japanese National Patent Publication No. 11-507629 JP 2001-355070 A Japanese Patent Laid-Open No. 5-98444 JP 7-500318 JP-A-7-188271

  An object of the present invention is to stably obtain a multicomponent lanthanide-based composite oxide thin film having a desired composition.

The inventors of the present invention have intensively studied to solve such a problem. As a result, a neutral ligand is coordinated to the lanthanide metal atom of the β-diketone lanthanide complex to shield the raw material other than the lanthanide metal. We found that the conversion efficiency of lanthanide-based metals into films can be significantly increased by reducing the reactivity with compounds.
The present invention is a CVD raw material for producing a thin film containing at least one lanthanide-based metal and at least one metal other than the lanthanide-based metal. The compound represented by the following formula (I) and an organometallic compound other than the lanthanide-based metal are used as solvents. The ΔTG graph obtained by dissolving the compound represented by formula (I) by thermogravimetric balance analysis (TG) relates to a CVD raw material having only one vaporization point peak .
Ln (β-dik) ₃ · L (I)
(However, Ln is a lanthanide metal atom, β-dik is dipivaloylmethane (DPM), diisobutyrylmethane (DIBM), isobutyrylpivaloylmethane (IBPM), 2,2,6,6-tetra Methyl-3,5-octanedione (TMOD), 6-ethyl-2,2-dimethyl-3,5-octanedione, 5-methyl-2,4-hexanedione, 5,5-dimethyl-2,4- At least one β-diketone selected from the group consisting of hexanedione, pentafluoropropanoylpivaloylmethane, 2,4-octanedione, and 6-ethyl-2,2-dimethyl-3,5-decanedione, L Represents at least one neutral ligand selected from the group of 1,10-phenanthroline (phen), 2,2′-bipyridyl (bpy) and derivatives thereof.

  A thin film containing a lanthanide-based metal and a metal other than the lanthanide-based metal was prepared using the compound of formula (I) of the present invention to produce a CVD raw material solution, and the film was converted to a lanthanide-based metal. The efficiency has improved dramatically by 3 to 100 times or more. As a result, the amount of lanthanide-based metal raw material used could be greatly reduced. Moreover, the conversion efficiency of metals other than lanthanide complexes was improved by reducing the total amount of solvent used. This is presumably because the amount of energy used for the film-forming reaction has increased due to a decrease in the total amount of solvent used to deprive the energy necessary for the film-forming reaction. Therefore, the present invention can stably produce a high-quality lanthanide-based metal-containing thin film having a target composition.

The present invention is described in detail below.
In the compound of the formula (I) of the present invention (β-diketone lanthanide complex neutral ligand adduct), a positive trivalent ion of a lanthanide metal forms a metal complex with three β-diketones. It is the one to which the sex ligand is added.
The lanthanide-based metal is a lanthanum series element described in the periodic table of elements, and ranges from lanthanum with atomic number 57 to lutetium with atomic number 71. Preferred examples include lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), and ytterbium (Yb).

Examples of the β-diketone of the present invention include dipivaloylmethane (DPM), diisobutyrylmethane (DIBM), isobutyrylpivaloylmethane (IBPM), 2,2,6,6-tetramethyl-3, 5-octanedione (TMOD), acetylacetone, hexafluoroacetylacetone, 6-ethyl-2,2-dimethyl-3,5-octanedione, 5-methyl-2,4-hexanedione, 5,5-dimethyl-2, Examples include 4-hexanedione, pentafluoropropanoylpivaloylmethane, 2,4-octanedione, and 6-ethyl-2,2-dimethyl-3,5-decanedione. DPM, DIBM, IBPM, and TMOD are preferable.
In the case of producing a lanthanide oxide single film using a β-diketone lanthanide complex, the conversion efficiency into the film is not significantly different from that of the raw material compound other than the lanthanide metal. From this, when producing a complex oxide thin film with a β-diketone lanthanide complex, the lanthanide complex is not easily introduced into the film due to a reaction with a raw material compound or solvent containing other metals (binuclear complex, reaction). It is considered that the intermediate has changed to an intermediate.

The neutral ligand of the present invention is not eliminated upon vaporization of the compound of formula (I) (β-diketone lanthanide complex neutral ligand adduct). There is a thermogravimetric balance differential thermal analysis (TG-DTA) as a method for examining the absence of neutral ligand desorption at the time of vaporization. “There is no elimination of neutral ligands upon vaporization” means that the ΔTG graph obtained by subjecting the compound of formula (I) to thermogravimetric balance analysis (TG) has only one vaporization point peak, Means that there is no inflection point indicating another vaporization point peak. The presence of other vaporization point peaks indicates that only the neutral ligand has been desorbed first during vaporization.
FIG. 1 shows TG-DTA data of tris (2,2,6,6-tetramethyl-3,5-octanedionato) neodymium / 1,10-phenanthroline adduct, which is a compound of formula (I) (in Ar flow) , Normal pressure). In the figure, the thin line represents the TG curve and the thick line represents the ΔTG curve. In FIG. 1, a uniform TG decrease curve is drawn until the end of vaporization, and ΔTG shows only a peak of 1. Also, La (TMOD) ₃ · phen and Nb (IBPM) ₃ · phen shown in FIGS. 2 and 3, respectively, draw a uniform TG decrease curve until the end of vaporization, and ΔTG shows only a peak of 1. On the other hand, TG-DTA data of tris (2,2,6,6-tetramethyl-3,5-octanedionato) neodymium tetraglyme adduct (Nd (TMOD) ₃ .tetraglyme) shown in FIG. 5 as a comparative example. In (Ar flow, normal pressure), the TG decrease curve has two or more baselines, and the ΔTG graph represents the main peak and the second peak on the left shoulder thereof. Therefore, this adduct is outside the scope of the present invention.
The vaporization temperature varies depending on the other raw materials used and the type of vaporizer, but even if the TG decrease curve is uniform, ΔTG does not show any other peak other than the main peak, and the vaporization temperature is set at the set vaporization temperature. Any neutral ligand that is not released can be used in the present invention.
Examples of the neutral ligand of the present invention include 1,10-phenanthroline (phen), 2,2′-bipyridyl (bpy), and derivatives thereof.

  The organometallic compound other than the lanthanide metal used in the present invention is a complex in which a coordination compound is coordinated to a metal, an organometallic compound in which an organic compound is bonded to a metal, or the like. The metal contained in the organometallic compound is a metal usually used in the solution CVD method. For example, bismuth (Bi), strontium (Sr), barium (Ba), yttrium (Y), zirconium (Zr), manganese ( Mn), iron (Fe), cobalt (Co), copper (Cu), titanium (Ti), lead (Pb), zinc (Zn), calcium (Ca), tantalum (Ta), niobium (Nb), lithium ( Li), potassium (K), rubidium (Rb), ruthenium (Ru), hafnium (Hf), iridium (Ir), platinum (Pt), gallium (Ga), aluminum (Al), indium (In), tin ( Sn), nickel (Ni), etc. are mentioned. Bi, Sr, Ba, Ti, Pb, Ni, Ta, Nb and Zr are preferable.

  As the compound that coordinates or bonds to the metal in the organometallic compound, those usually used in the solution CVD method can be used. For example, dipivaloylmethane (DPM), pentafluoropropanoylpivaloylmethane, diisobutyrylmethane (DIBM), isobutyrylpivaloylmethane (IBPM), acetylacetone, hexafluoroacetylacetone, 2,2,6, 6-tetramethyl-3,5-octanedione (TMOD), 6-ethyl-2,2-dimethyl-3,5-octanedione (EDMOD), 2,4-octanedione, 6-ethyl-2,2- Dimethyl-3,5-decanedione, 1,5-cyclooctadiene, cyclopentadiene, methylcyclopentadiene, ethylcyclopentadiene, diethylmethylamine, triethylamine, triethylenetetramine, triethylphosphine, triethylvinylsilane, bistrimethylsilylacetylene, dio , To other compounds, such as dialkyl amide complexes, alkoxide, Gurikokishido, phenyl, Orutotoriru (o-Tol), para-tolyl (p-Tol), it includes groups such as ortho-ethylphenyl.

Examples of the diol include 1,3-propanediol and 2-methyl-2,4-pentanediol. Examples of the dialkylamide complex include diethylamide, dimethylamide, and ethylmethylamide. Examples of the alkoxide include isopropoxide (Oi-Pr), ethoxide, methoxide, t-amyloxide (Ot-Am), t-butoxide (Ot-Bu), sec-butoxide (Os-Bu), 1-methoxy-2- Examples thereof include methyl-2-propoxide and 2-ethoxyethoxide. Preferably dipivaloylmethane, pentafluoropropanoylpivaloylmethane, diisobutyrylmethane, isobutyrylpivaloylmethane, acetylacetone, hexafluoroacetylacetone, 2,2,6,6-tetramethyl-3,5- Octanedione, alkoxide, cyclopentadiene or derivatives thereof. One or more of the above compounds can be used, and the organometallic compound of the present invention may be a compound in which a part of an alkoxide such as Ti (Oi-Pr) ₂ (DPM) ₂ is substituted with a β-diketone.

As a compound of the formula (I) in which a neutral ligand is not eliminated upon vaporization (a neutral ligand adduct of a β-diketone lanthanide complex), La (TMOD) ₃ .phen, Nd (TMOD) ₃・ Phen, Nd (IBPM) ₃・ phen, La (DPM) ₃・ phen, La (DPM) ₃・ bpy, La (DIBM) ₃・ phen, La (DIBM) ₃・ bpy, La (IBPM) ₃・ phen , La (IBPM) ₃ · bpy, La (DIBM) ₃ · phen, La (DIBM) ₃ · bpy, Ce (DPM) ₃ · phen, Ce (DPM) ₃ · bpy, Ce (DIBM) ₃ · phen, Ce _{(DIBM) 3 · bpy, Ce} (IBPM) 3 · phen, Ce (IBPM) 3 · bpy, Ce (DIBM) 3 · phen, Ce (DIBM) 3 · bpy, Pr (DPM) 3 · phen, _{r (DPM) 3 · bpy,} Pr (DIBM) 3 · phen, Pr (DIBM) 3 · bpy, Pr (IBPM) 3 · phen, Pr (IBPM) 3 · bpy, Pr (DIBM) 3 · phen, Pr ( DIBM) ₃ · bpy, Nd (DPM) ₃ · phen, Nd (DPM) ₃ · bpy, Nd (DIBM) ₃ · phen, Nd (DIBM) ₃ · bpy, Nd (IBPM) ₃ · phen, Nd (IBPM) ₃ · bpy, Nd (DIBM) ₃ · phen, Nd (DIBM) ₃ · bpy, Sm (DPM) ₃ · phen, Sm (DPM) ₃ · bpy, Sm (DIBM) ₃ · phen, Sm (DIBM) ₃ · _{bpy, Sm (IBPM) 3 ·} phen, Sm (IBPM) 3 · bpy, Sm (DIBM) 3 · phen, Sm (DIBM) 3 · bpy, Eu (DPM) 3 · phen _{Eu (DPM) 3 · bpy,} Eu (DIBM) 3 · phen, Eu (DIBM) 3 · bpy, Eu (IBPM) 3 · phen, Eu (IBPM) 3 · bpy, Eu (DIBM) 3 · phen, Eu ( DIBM) ₃ · bpy, Gd (DPM) ₃ · phen, Gd (DPM) ₃ · bpy, Gd (DIBM) ₃ · phen, Gd (DIBM) ₃ · bpy, Gd (IBPM) ₃ · phen, Gd (IBPM) ₃ · bpy, Gd (DIBM) ₃ · phen, Gd (DIBM) ₃ · bpy, Yb (DPM) ₃ · phen, Yb (DPM) ₃ · bpy, Yb (DIBM) ₃ · phen, Yb (DIBM) ₃ · _{bpy, Yb (IBPM) 3 ·} phen, Yb (IBPM) 3 · bpy, Yb (DIBM) 3 · phen, Yb (DIBM) but ₃ · bpy etc., these Ri the present invention is not limited.

  The concentration of the compound of formula (I) and the organometallic compound in the CVD raw material for thin film of the present invention is not particularly limited as long as it can provide a stable solution. The concentration is appropriately selected depending on the transport amount of the raw material, the film formation rate at the time of film production, and the like, but a concentration of about 5 to 70% of the saturated concentration at room temperature (25 ° C.) can be preferably used. The solution concentration cannot be uniformly defined because the solubility differs depending on the raw material, but is usually 0.02 to 1 mol / liter, preferably 0.05 to 0.8 mol / liter. If it is less than this range, problems such as deterioration of the raw material solution over time, reduction of the film formation rate, deterioration of the formed thin film surface, and incorporation of carbon into the formed thin film tend to occur. On the other hand, when the above range is exceeded, the raw material is precipitated with the vaporization of the solvent, and the vaporization chamber is easily clogged.

  As the solvent of the present invention, a solvent that does not react with the compound of formula (I) is selected. For example, THF, acetic acid n-butyl ester (butyl acetate), benzene, toluene, hexane, octane, cyclohexane, methylcyclohexane, ethylcyclohexane, 1,2-epoxycyclohexane, methanol, ethanol, isopropyl alcohol, diethylene glycol dimethyl ether (diglyme), Acetone, methyl ethyl ketone, 1,2-dimethoxyethane and the like can be mentioned. The solution concentration is appropriately selected depending on the solution concentration, the film formation speed during film production, the structure of the vaporization chamber, the vaporization method, and the like within a range where the vaporization chamber is not clogged and change with time is difficult to occur.

  A nucleophilic reagent may be used as the organometallic compound and / or solution stabilizer of the present invention. Examples of stabilizers include ethylene glycol ethers such as glyme, diglyme, triglyme and tetraglyme, 18-crown-6, dicyclohexyl-18-crown-6, 24-crown-8, dicyclohexyl-24-crown-8, dibenzo Crown ethers such as -24-crown-8, ethylenediamine, N, N'-tetramethylethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, 1,1,4,7,7-pentamethyl Polyamines such as diethylenetriamine, 1,1,4,7,10,10-hexamethyltriethylenetetramine, cyclic polyamines, β-ketoesters such as methyl acetoacetate, ethyl acetoacetate, and 2-methoxyethyl acetoacetate Alternatively, β-diketones can be mentioned. The usage-amount of the said stabilizer is 0.1-10 mol normally with respect to 1 mol of metal compounds, Preferably it is 1-4 mol.

  Moreover, as a thin film obtained using the CVD raw material for thin film of the present invention, bismuth lanthanum titanate, bismuth neodymium titanate, lead lanthanum zirconate titanate, lanthanum titanate, lanthanum nickelate, samarium nickelate, zirconate Examples include thin films composed of gadolinium, lanthanum strontium cobaltate, praseodymium calcium manganate, cerium manganate, neodymium barium copper oxide, dysprosium barium copper oxide, ytterbium barium copper oxide, cerium barium yttrium oxide, and the like. These are very useful in many fields, and can be used for superconductors, dielectrics, conductors, in particular, capacitor dielectrics, piezoelectric resonators, infrared sensors, and the like.

When producing an oxide thin film (multicomponent system) composed of a plurality of metal components by the solution vaporization CVD method, the raw material solution is generally mixed and vaporized by any of the following methods (1) to (4). The
(1) A plurality of raw material solutions in which an organometallic compound containing a target metal is separately dissolved are mixed immediately before being supplied to the vaporizing chamber, and the mixed solution is supplied to one vaporizing chamber (multi-bottle A type).
(2) The plurality of raw material solutions are separately supplied directly to one vaporizing chamber (multi-bottle B type).
(3) Vapors obtained by vaporizing the plurality of raw material solutions separately in a plurality of vaporization chambers are mixed (multi-bottle C type).
(4) One raw material solution (hereinafter also referred to as “cocktail”) containing a plurality of organometallic compounds in a specific ratio is directly supplied to one vaporizing chamber (one-bottle type).
The above (1) to (3) are easy to change the composition, and (4) is excellent in equipment cost, operation cost and operation controllability of the apparatus. Since the CVD raw material for thin film of the present invention may be composed of two or more raw material solutions or one solution (cocktail) containing two or more organic metal compounds, the above (1) to (4) It can be applied to both.

As a thin film manufacturing method, a method known to those skilled in the art can be used, and examples thereof include methods such as thermal CVD, plasma CVD, and photo CVD. In the case of thermal CVD, the raw material is vaporized into vapor (vaporization stage), the raw material vapor is introduced onto the substrate, and then the raw material is decomposed on the substrate to grow a thin film on the substrate (deposition stage). In the vaporization stage, in order to improve the vaporization rate of the raw material and prevent decomposition, it is preferable to carry out under a reduced pressure of 13330 Pa or less, particularly 8000 Pa or less and below the decomposition temperature of the raw material. The substrate is preferably heated in advance to a decomposition temperature of the raw material or higher, preferably 350 ° C. or higher, more preferably 450 ° C. or higher. Further, the obtained thin film may be annealed as necessary.
Any apparatus may be used as the thin film manufacturing apparatus according to the present invention. For example, an apparatus used in a metal-organic chemical vapor deposition (MOCVD) method as shown in FIG.

  Specifically, first, the compound of formula (I) is dissolved in an organic solvent at a concentration of, for example, 0.05 to 1 mol / l. Similarly, a solution of a CVD raw material other than the lanthanide metal necessary for manufacturing the target film is also prepared. In addition, the mixing ratio of the respective CVD raw materials when preparing the cocktail raw material solution is not necessarily the same as the composition of the target film, and an optimum one is selected according to the film forming conditions and the apparatus structure.

  In order to produce a lanthanide-based metal-containing thin film using the solution prepared as described above, for example, in the case of the multi-bottle A type, a solution vaporization CVD apparatus as shown in FIG. 7 can be used. Fill the raw material container with the raw material solution containing the compound of formula (I) and attach it to the solution vaporization CVD apparatus, and fill the other raw material container with the raw material solution containing the organometallic compound other than the lanthanide metal to the solution vaporization CVD apparatus. The vaporization chamber temperature is set to 150 to 300 ° C., for example, and the raw material solution supply flow rate is set to 0.1 to 1 ml / min and supplied to the vaporization chamber. The whole amount of the raw material solution supplied is vaporized and fed into the reaction chamber using an inert gas such as Ar as a carrier gas. For example, oxygen can be used as the oxidizing gas. When the pressure in the reaction chamber is kept at 0.1 to 50 torr and the substrate placed in the reaction chamber is heated to 400 to 850 ° C., a lanthanide metal-containing thin film can be formed on the substrate.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, the following Example does not limit the scope of the present invention.
Example 1 (Preparation of solution)
2.75 g of Nd (TMOD) ₃ · phen was dissolved in toluene to 100 ml to obtain a solution having a concentration of 0.03 mol / l. Also, 4.82 g of Bi (o-Tol) ₃ was dissolved in toluene to make 100 ml, and 5.32 g of Ti (Oi-Pr) ₂ (DPM) ₂ was dissolved in toluene to make 100 ml. A 0.1 mol / l solution was prepared.

(Manufacture of thin film; multi-bottle A type)
Using the normal hot wall type solution vaporization CVD apparatus having the ternary material heating system shown in FIG. 7, the raw material solutions are respectively supplied from the raw material container to the vaporization chamber (temperature: 230 ° C.) by pressurization of helium gas. The solution was supplied at a solution of 0.25 ml / min, a Bi raw material solution of 0.35 ml / min, and a Ti raw material solution of 0.3 ml / min. 0.75: 3). The entire amount of the raw material solution supplied to the vaporizing chamber is vaporized, and the generated vapor is supplied from the vaporizing chamber (pressure: 47 hPa) to the reaction chamber (pressure: 10.7 hPa, temperature: 250 ° C.) by Ar carrier gas (200 ml / min). did. On the Pt / TiO ₂ / Si substrate in the reaction chamber (temperature: 550 ° C.), the reaction gas was oxygen (flow rate 100 ml / min) and film formation was performed for 10 minutes. The composition analysis results of the obtained film by ICP (inductively coupled plasma emission spectrometry) were Bi: 80.1 μg / cm ² , Nd: 9.7 μg / cm ² , Ti: 16.2 μg / cm ² , and the molar ratio Was Ti: 3 and Bi: Nd: Ti = 3.40: 0.60: 3. This was almost equal to the composition molar ratio of the target bismuth neodymium titanate 3.25: 0.75: 3. As the capacitor characteristics of the obtained thin film, the remanent polarization when 5 V was applied and the leak current density when DC voltage 1.5 V was applied were ² Pr = 18 μC / cm ² and 1 × 10 ⁻⁸ A / cm ² or less.

Comparative Example 1
Nd (TMOD) ₃ (2.21 g) was dissolved in toluene to 100 ml to obtain a solution having a concentration of 0.03 mol / l. The same Bi and Ti raw material solution as in Example 1 was used, and a film was formed in the same manner as in Example 1. The result of composition analysis of the obtained film was Bi; 84.6 μg / cm ² , Nd; 0 0.72 μg / cm ² , Ti; 16.8 μg / cm ² , and the molar ratio was Bi: Nd: Ti = 3.46: 0.04: 3 with Ti = 3. The Nd ratio was very low with respect to the composition molar ratio of the target bismuth neodymium titanate. The remanent polarization and leakage current density of the obtained thin film were 2Pr = 1.5 μC / cm ² and 4 × 10 ⁻⁷ A / cm ² .

Comparative Example 2
2.88 g of Nd (TMOD) ₃ · tetraglyme was dissolved in toluene to 100 ml to obtain a solution having a concentration of 0.03 mol / l. The same Bi and Ti raw material solution as in Example 1 was used, and a film was formed in the same manner as in Example 1. The result of composition analysis of the obtained film was Bi; 83.9 μg / cm ² , Nd; 0 .88 μg / cm ² , Ti; 16.6 μg / cm ² , and the molar ratio was Bi: Nd: Ti = 3.48: 0.05: 3 with Ti = 3. The Nd ratio was very low with respect to the composition molar ratio of the target bismuth neodymium titanate. The remanent polarization and leakage current density of the obtained thin film were 2Pr = 1.8 μC / cm ² and 3 × 10 ⁻⁷ A / cm ² .

Example 2 (Preparation of mixed solution)
11.24 g of La (TMOD) ₃ .phen and 2.95 g of bis [diisobutyrylmethanato] nickel (Ni (DIBM) ₂ ) were dissolved in toluene to make 100 ml, and the cocktail solution (concentration was 0.8% each). 12 mol / l and 0.08 mol / l) were prepared.

(Manufacture of thin film; one bottle type)
Using a normal hot wall type CVD apparatus, the cocktail solution prepared above was introduced into the vaporization chamber (temperature: 230 ° C.) at 0.3 ml / min to vaporize, and the generated vapor was converted into an Ar carrier gas (200 ml / min). ) Was supplied from the vaporization chamber (pressure: 47 hPa) to the reaction chamber (pressure: 10.7 hPa, temperature: 250 ° C.). On the silicon single crystal substrate in the reaction chamber, the reaction gas was oxygen (flow rate 100 ml / min) and film formation was performed for 10 minutes. The composition analysis results of the thin film obtained at the substrate temperature of 600 ° C. are La; 41.9 μg / cm ² , Ni; 17.6 μg / cm ² , and the molar ratio is La: Ni = 1.01: 1.00. there were. This was almost equal to the target molar ratio of 1: 1 lanthanum nickelate. The specific resistance of the thin film obtained at a substrate temperature of 600 ° C. was 8 × 10 ⁻⁴ Ωcm ² .

Comparative Example 3
8.77 g of La (TMOD) ₃ and 2.95 g of (Ni (DIBM) ₂ ) were dissolved in toluene to make 100 ml, and cocktail solutions (concentrations were 0.12 mol / l and 0.08 mol / l, respectively) Was prepared. The composition analysis results of the thin film obtained at the substrate temperature of 600 ° C. are La; 11.6 μg / cm ² , Ni; 17.4 μg / cm ² , and the molar ratio is La: Ni = 0.28: 1.00. there were. The La ratio was very low with respect to the compositional molar ratio of the target lanthanum nickelate. The specific resistance was 2 × 10 ⁻² Ωcm ² .

  As described above, the CVD raw material for thin film production of the present invention dramatically improves the conversion efficiency of lanthanide-based metal into a film, and stabilizes a high-quality lanthanide-based metal-containing thin film with a low amount of raw material and solvent. Could be manufactured.

It is the figure which showed the thermogravimetric balance (TG) analysis graph of Nd (TMOD) ₃ * phen (Example 1). It is the figure which showed the TG analysis graph of La (TMOD) ₃ * phen (Example 2). It is the figure which showed the TG analysis graph of Nd (IBPM) ₃ * phen. It is the figure which showed the TG analysis graph of Nd (TMOD) ₃ (comparative example 1). It is the figure which showed the TG analysis graph of Nd (TMOD) ₃ * tetraglyme (comparative example 2). It is the figure which showed the TG analysis graph of La (TMOD) ₃ (comparative example 3). It is the figure which showed an example of the solution vaporization CVD apparatus.

Explanation of symbols

1: Raw material container 2: Cleaning solvent container 3: Mass flow controller (gas)
4: Mass flow controller (liquid)
5: Vaporization chamber 6: Reaction chamber 7: Substrate 8: Trap 9: Vacuum pump 10: Thin film production apparatus 15; Carrier gas (Ar)
16: exhaust gas

Claims (5)

A CVD raw material for thin film production containing one or more lanthanide-based metals and one or more metals other than lanthanide-based metals, wherein a compound represented by the following formula (I) and an organometallic compound other than a lanthanide-based metal are dissolved in a solvent: A ΔTG graph obtained by subjecting the compound represented by the formula (I) to thermogravimetric balance analysis (TG) is a CVD raw material for thin film production having only one vaporization point peak.
Ln (β-dik) ₃ · L (I)
(However, Ln is a lanthanide metal atom, β-dik is dipivaloylmethane (DPM), diisobutyrylmethane (DIBM), isobutyrylpivaloylmethane (IBPM), 2,2,6,6-tetra Methyl-3,5-octanedione (TMOD), 6-ethyl-2,2-dimethyl-3,5-octanedione, 5-methyl-2,4-hexanedione, 5,5-dimethyl-2,4- At least one β-diketone selected from the group consisting of hexanedione, pentafluoropropanoylpivaloylmethane, 2,4-octanedione, and 6-ethyl-2,2-dimethyl-3,5-decanedione, L Represents at least one neutral ligand selected from the group of 1,10-phenanthroline (phen), 2,2′-bipyridyl (bpy) and derivatives thereof. The CVD raw material for thin film production according to claim 1, wherein the metal other than the lanthanide metal is at least one selected from the group consisting of Bi, Sr, Ba, Ti, Pb, Ni, Ta, Nb and Zr. The organometallic compound is a metal dipivaloylmethanato, pentafluoropropanoylpivaloylmethanato, diisobutyrylmethanato, isobutyrylpivaloylmethanato, 2,2,6,6-tetramethyl-3,5-octane The CVD raw material for producing a thin film according to claim 1 or 2, which is at least one of diato, dioleate, dialkylamide complex, alkoxide, cyclopentadienyl or a derivative thereof. The CVD raw material for thin film production according to claim 3, wherein the alkoxide is methoxide, ethoxide, isopropoxide, t-butoxide, or t-amyloxide. The thin film manufacturing method using the CVD raw material for thin film manufacture of any one of Claims 1-4.

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