JPH04257592A - Metal complexes for forming new thin films - Google Patents

Abstract

PURPOSE:To obtain a new metal complex for thin film having excellent vaporiza tion characteristics in the case of use by chemical vapor-phase deposition method, stably providing a raw material for a long period of time, comprising an addition product of a specific alkaline earth metal complex with a ligand. CONSTITUTION:The objective complex comprising an addition product of an alkaline earth metal complex shown by the formula (M is alkaline earth metal; R1 to R4 are lower alkyl and/or aromatic group) with a ligand. For example, bis-2,2,6,6-tetramethyl-3,5-heptanedionate barium [Ba(DPM)2 for short] may be cited as the alkaline earth metal complex. 1,10-Phenanthroline may be used as the ligand. The objective complex, for example, is obtained by dripping an aqueous solution of 1,10-phenanthroline monohydrate into a solution of barium hydroxide octahydrate, blending while stirring, dropping DPM into the blend and reacting.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal complex for forming a thin film, which is composed of an adduct of an alkaline earth metal complex and is used in a vapor deposition method or the like.

0002

[Prior art and problems to be solved by the invention] Conventionally,
Regarding β-diketone complexes of alkaline earth metals (hereinafter referred to as alkaline earth metal complexes), Inorganic
Chemistry Vol. 2 No. 1, P.
73, 1963, but a compound in which a ligand is added to an alkaline earth metal complex has not yet been reported.

On the other hand, regarding the vaporization characteristics of alkaline earth metal complexes, analytical chemistry
Vol. 42, No. 14, P. 1828 (197
0), and a barium complex exhibiting very excellent vaporization properties was reported at the 37th Spring 1990 Applied Physics Conference (29p-V-13). However, although conventional alkaline earth metal complexes exhibit excellent vaporization properties initially, their vaporization properties deteriorate rapidly over time, making it difficult to form stable thin films. .

As a result of extensive research, the present inventors have found that an adduct of an alkaline earth metal complex and a ligand is useful as a complex for forming a thin film, and has completed the present invention.

[0005]

[Means for Solving the Problems] That is, the present invention solves the problems by the general formula (
I) (wherein M is an alkaline earth metal, R1, R2, R
3. A novel thin film-forming metal complex comprising an adduct of an alkaline earth metal complex and a ligand, each of which is represented by R4 (representing the same or different lower alkyl group and/or aromatic group);

A novel metal complex for forming a thin film according to claim 1, wherein the ligand is a polyether compound or a chelating agent.

A novel metal complex for forming a thin film according to claim 1 or 2, wherein the chelating agent is an orthophenanthroline derivative or a bipyridyl derivative.

Claims 1 to 3 wherein said alkaline earth metal is barium, strontium, calcium or magnesium.
The novel metal complex for forming a thin film according to any one of the preceding items.

[0009]

[Operation] The present invention will be explained in more detail below. The most important feature of the present invention is that it is an adduct of an alkaline earth metal complex and a ligand. As described above, alkaline earth metal complexes as adducts are excellent as raw materials for forming thin films. Especially when used in a chemical vapor deposition method, it has excellent vaporization properties and can stably supply raw materials over a long period of time.

Here, examples of alkaline earth metal complexes include: bis-2,2,6,6-tetramethyl-3,5-heptanedionatobarium [Ba(DPM)2] bis-2,8- Dimethyl-4,6-nonanedionatobarium [Ba(DIVM)2] Bis-4,6-nonanedionatobarium [Ba(DBM)
)2] Bis-2,4-pentanedionatobarium [Ba(ac
ac)2] Bis-1-phenyl-1,3-butanedionato Strontium bis-1-(2-furyl)-1,3-butanedionatocalcium bis-2,2-dimethyl-3,5-octanedio Examples include natomagnesium.

Examples of polyether compounds include bis-
(2-ethoxyethyl)ether 1,2bis(2-methoxyethoxy)ethane 2,5,8,11,14-pentaoxapentadecanbis(2-butoxyethyl)ether 1,4,7,10,13,16 -hexaoxacyclooctadecane 1,4,10,13-tetraoxa-7,16-diazacyclooctadecane 4,7,10,16,19,24,27-heptaoxa-1,13-diazabicyclo[11,8 , 8] nonacosane 1,4,10,13-tetrathia-7,16-diazacyclooctadecane 2,3,11,12-dicyclohexano-1,4,7,
10,13,16-hexaoxacyclooctadecane

[
[0012] Abbreviations include [18-crown-6] [4,13-diaza-18-crown-6] [talyptand [3,2,2]], etc.

[0013] As the chelating agent, 2,2'-bifuran 2,2'-bithiophene 2,2'-dipyridylmethane 2,2'-Bioxazole Examples include.

As orthophenanthroline derivatives,
Examples include 1,10-phenanthroline [phen] 4,7-dimethyl-1,10-phenanthroline and 4,7-diphenyl-1,10-phenanthroline.

As the bipyridyl derivative, bipyridine [
bpy] 2,2'-biquinoline, 2,2'-bipyrazine, 4,7-diphenyl-2,9-dimethyl-1,10-phenanthroline, and the like.

The molar ratio of the alkaline earth metal complex to the ligand is 1 or 2, depending on the ligand.

[0017] The vaporization characteristics can be seen by the thermogravimetric loss measured on a thermobalance. Thermogravimetric reduction is 5℃/
This is the value of weight loss when the temperature is raised from room temperature to 500°C at a constant temperature of 50 minutes. The stability of vaporization characteristics can be seen by comparing the thermogravimetric loss immediately after synthesis and after 6 months (at room temperature, in air).

FIG. 1(a) shows the thermogravimetric loss immediately after the synthesis of Ba(DPM)2, and FIG. 1(b) shows the thermogravimetric loss after 6 months. From these figures, it can be seen that the vaporization characteristics have deteriorated.

When forming a thin film using the metal complex for forming a thin film of the present invention, a liquid phase deposition method or a vapor phase deposition method may be used, and the vapor phase deposition method is particularly preferred. When forming a thin film using the metal complex for forming a thin film of the present invention, it is possible to form a thin film under pressure, normal pressure, or reduced pressure, but normal pressure or reduced pressure is preferable.

When forming a thin film using the metal complex for forming a thin film of the present invention, accompanying gases include helium, argon, nitrogen, etc., and reactive gases include oxygen, water, nitrous oxide, ozone, etc.

[0021]

EXAMPLES The present invention will be explained in detail below, but the present invention is not limited to these examples in any way. Production example of [Ba(DPM)2(phen)2] 1.7g
2. in an aqueous solution in which barium hydroxide octahydrate of 2.
DP
2.2 g of M was added dropwise at room temperature, and the reaction was completed in about 1 hour. Next, water was added to this reaction solution for crystallization and filtration to obtain 9.2 g of the target compound. Furthermore, this target compound was purified by recrystallization using ethanol, and 8.5 g of the target compound was recovered.

Figures 2(a) and 2(b) show [Ba(DPM
)2(phen)2]. Also, Figure 1
(a) and (b) show the thermogravimetric loss values of Ba(DPM)2 immediately after synthesis and when stored in a sample bottle at room temperature in the air for 6 months. When [Ba(DPM)2(phen)2] changes from 92wt% to 90.8wt%, Ba(DPM)2(phen)2]
PM)2 changed from 89 wt% to 53 wt%.

Production and Experimental Example 2 Production Example of [Ba(DPM)2(18-crown6)] An aqueous solution in which 15 g of barium hydroxide octahydrate was dissolved and 13 g of 18-crown-6-ether were dissolved. After stirring and mixing the methanol solution at room temperature for 6 hours, DPM2
0 g was added dropwise at room temperature, and the reaction was completed in about 3 hours. Next, methanol was removed from the reaction solution under reduced pressure to cause crystallization, followed by filtration to obtain 29 g of the target compound. Furthermore, this target compound was purified by recrystallization using methanol, and 20 g of the target compound was recovered.

[Ba(DPM)2(18-crown-
6) 2] has a thermogravimetric loss value of 93.5 wt% immediately after synthesis.
On the other hand, the sample stored in a sample bottle at room temperature in the atmosphere for 6 months had a concentration of 92.3 wt%.

Production and Experimental Example 3 Production Example of [Ba(DIVM)2(bpy)2] 7.5g
An aqueous solution in which barium hydroxide octahydrate of 7.8
An ethanol solution in which g of 2,2-bipyridine was dissolved was stirred and mixed at 40°C for about 3 hours, cooled to room temperature, and then DI
8.6 g of VM was added dropwise at room temperature, and the reaction was completed in about 2 hours. Next, ethanol was removed from the reaction solution under reduced pressure to crystallize it, followed by filtration to obtain 16.8 g of the target compound. Furthermore,
This target compound was purified by recrystallization using ethanol, and 12 g of the target compound was recovered.

[Ba(DIVM)2(bpy)2] is
The thermogravimetric loss value immediately after synthesis was 86.5 wt%, but 6
The sample stored in a sample bottle at room temperature in the atmosphere for a month had a concentration of 84.6 wt%.

Production and Experimental Example 5 [Sr(DBM)2 (cryptand [3,2,2])]
D
2.9 g of BM was added dropwise at room temperature, and the reaction was completed in about 3 hours. Next, methanol was removed from the reaction solution under reduced pressure to cause crystallization, followed by filtration to obtain 5.3 g of the target compound. Furthermore,
This target compound was purified by recrystallization using methanol, and 3.4 g of the target compound was recovered.

[Sr(DBM)2(cryptand[3,
2,2])] has a thermogravimetric loss value of 79.5w immediately after synthesis.
Compared to t%, the sample stored in the sample bottle at room temperature in the atmosphere for 6 months was 77.9wt%.

Preparation and Example 6 [Sr(DPM)2(4,13-diaza-18-c
[row-6)] An aqueous solution in which 2.1 g of strontium hydroxide octahydrate was dissolved and a methanol solution in which 2.4 g of 4,13-diaza-18-crown-6-ether were dissolved were mixed at room temperature for about 4 After stirring and mixing for an hour, 3.8 g of DPM was added dropwise at room temperature to complete the reaction in about 3 hours. Next, methanol was removed from this reaction solution under reduced pressure to crystallize it, and then it was filtered to obtain 4.1 g of the target compound. Furthermore, this target compound was purified by recrystallization using methanol, and 2.7 g of the target compound was recovered.

[Sr(DPM)2(4,13-diaz
a-18-crown-6)] had a thermogravimetric loss value of 93.2 wt% immediately after synthesis, whereas that of the sample stored in a sample bottle at room temperature in the atmosphere for 6 months was 92.1 wt%.
Met.

Production and Experimental Example 7 Production Example of [Ca(DPM)2(phen)2] DPM163 was added to an aqueous solution in which 30 g of sodium hydroxide was dissolved.
After stirring for about 1 hour, 4 g of methanol solution was added dropwise at room temperature.
Add 1.6 g of calcium chloride and stir for about 1 hour. 150 g of 1,10-phenanthroline was added dropwise to this reaction solution while stirring under ice-cooling, and after returning the solution to room temperature, the reaction was completed in about 2 hours. Next, methanol was removed from the reaction solution under reduced pressure and crystallized, followed by filtration to obtain 370 g of the target compound.
I got it. Furthermore, this target compound was purified by recrystallization using methanol, and 340 g of the target compound was recovered.

[Ca(DPM)2(phen)2] is
The thermogravimetric loss value immediately after synthesis was 97.6 wt%, but 6
The sample stored in a sample bottle at room temperature in the atmosphere for a month had a concentration of 95.3 wt%.

Example 1 Using an apparatus for metalorganic chemical vapor deposition (hereinafter referred to as MOCVD), an MgO substrate was heated to 800° C. in a reaction chamber, and Ba(DPM)2.(
phen)2 was vaporized and introduced. Furthermore, by simultaneously introducing oxygen into this reaction chamber, a good BaO thin film could be formed. The film formation rate was 1 to 10 μm/h.

*sccm stands for Standard Cubic C
Abbreviation for entimeter per minute: 0°C
, volume of gas flowing in 1 minute at 1 atm (cm3)
It is.

Example 2 Using an apparatus for MOCVD method, an MgO substrate was heated to 750° C. and Ba(DPM) was heated using argon as a carrier gas.
)2(18-crown-6) was vaporized and introduced. By introducing oxygen at the same time, a good BaO thin film could be formed. The film formation rate was 1 to 10 μm/h.

[0036]

Example 3 Using an apparatus for MOCVD, a SrTiO 3 substrate was heated to 800° C. in a reaction chamber, and Ba(DIVM) 2 (bpy) 2 was vaporized and introduced using argon gas as a carrier gas. By introducing nitrous oxide at the same time, a good BaO thin film could be formed. Film formation speed is 2~
It was 8 μm/h.

[0038]

Example 4 Using an apparatus for MOCVD, a SrTiO3 substrate was heated to 750°C in a reaction chamber, and Sr(DBM)2 (cryptand [3,2,2]
) was vaporized and introduced. By introducing oxygen at the same time, a good SrO thin film could be formed. The film formation rate was 3 to 15 μm/h.

[0040]

Example 5 Using an apparatus for MOCVD method, a SrTiO3 substrate was heated to 800°C in a reaction chamber, and Sr(DPM)2(4,13-diaza-18
-crown-6) was vaporized and introduced. By introducing water vapor at the same time, a good SrO thin film could be formed. The film formation rate was 5 to 20 μm/h.

[0042]

Example 6 Using an apparatus for MOCVD method, a Mg0 substrate was heated in a reaction chamber for 70 minutes.
Ca(DPM)2(phen)2 was vaporized and introduced using argon gas as a carrier gas by heating to 00°C. By introducing oxygen at the same time, a good CaO thin film could be formed. The film formation rate was 5 to 15 μm/h.

[0044]

[0045]

Effects of the Invention By using the alkaline earth metal complex of the present invention, it is possible to form a thin film with long-term stability and high reproducibility by chemical vapor deposition, which is extremely advantageous industrially.

[0046]

[Brief explanation of the drawing]

Figure 1: (a) shows the thermogravimetric loss (%) immediately after synthesis of conventional Ba(DPM)2 and (b) stored in a sample bottle at room temperature in the atmosphere for 6 months. It shows the thermogravimetric loss (%) of the same compound.

FIG. 2(a) shows [Ba(
Thermogravimetric decrease immediately after synthesis of DPM)2(phen)2] (
%) and (b) shows the thermogravimetric loss (%) of the same compound stored in a sample bottle at room temperature in the atmosphere for 6 months.

Claims (4)

[Claims] Claim 1: General formula (I) (wherein M is an alkaline earth metal, R1, R2, R
3. A novel metal complex for forming a thin film, comprising an adduct of an alkaline earth metal complex represented by (3, R4 represents the same or different lower alkyl group and/or aromatic group) and a ligand. 2. The novel metal complex for forming a thin film according to claim 1, wherein the ligand is a polyether compound or a chelating agent. 3. Claim 1 or 2, wherein the chelating agent is an orthophenanthroline derivative or a bipyridyl derivative.
The described novel metal complex for forming a thin film. [Claim 4] Claim 1, wherein the alkaline earth metal is barium, strontium, calcium, or magnesium.
3. The novel metal complex for forming a thin film according to any one of items 3 to 3.