JP4453793B2 - Method for forming boron film - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for forming a boron film on a substrate. More specifically, the present invention relates to a method for forming a boron film that can efficiently form a boron film on a substrate with a simple operation or apparatus.
[0002]
[Prior art]
Boron thin films are used as materials for neutron detection and measurement instruments in the field of nuclear engineering.
The method for producing the boron thin film is said to be produced by the CVD (Chemical Vapor Deposition) method, but the details are not known.
[0003]
[Problems to be solved by the invention]
An object of the present invention is to provide a method for forming a boron film on a substrate.
Another object of the present invention is to provide a method for forming a boron film, which can efficiently form a boron film on a substrate, for example, at a high yield and a high formation rate with a simple operation and apparatus.
Still other objects and advantages of the present invention will become apparent from the following description.
[0004]
[Means for Solving the Problems]
According to the present invention, the above objects and advantages of the present invention are as follows. First, a borane complex is thermally decomposed at a temperature of 200 to 600 ° C. in the presence of an inert organic medium vapor. This is achieved by a method of forming a boron film.
[0005]
The borane complex used in the present invention is a complex of borane and a compound having an unpaired electron, such as a borane / sulfide complex, a borane / amine complex, or a borane / ether complex. The borane sulfide complex is a compound represented by a chemical formula: BH ₃ .SR ¹ R ² . R ¹ and R ^{2 in} SR ¹ R ² are each independently a monovalent organic group such as a hydrogen atom, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group or a phenyl group, and may be the same or different . Specific examples of borane / sulfide complexes include borane / dimethyl sulfide complex, borane / diethyl sulfide complex, borane / dipropyl sulfide complex, borane / dibutyl sulfide complex, borane / dipentyl sulfide complex, borane / diphenyl sulfide complex, borane / methyl. Examples thereof include an ethyl sulfide complex and a borane / methylphenyl sulfide complex, and a borane / dimethyl sulfide complex and a borane / diethyl sulfide complex are preferable.
[0006]
Similarly, specific examples of borane / amine complexes include borane / ammonia complexes, borane / methylamine complexes, borane / ethylamine complexes, borane / dimethylamine complexes, borane / diethylamine complexes, borane / trimethyl complexes, borane / triethyl complexes, Examples thereof include pyridine complexes, borane / pyrimidine complexes, borane / pyrazine complexes, borane / quinoline complexes, and borane / isoquinoline complexes. Examples of the borane / ether complex include borane / dimethyl ether complex, borane / diethyl ether complex, borane / methyl ethyl ether complex, borane / dipropyl ether complex, borane / dibutyl ether complex, and borane / dipentyl ether complex. it can.
Some of these compounds are also available as commercial products.
[0007]
In the present invention, the borane complex is subjected to thermal decomposition in the presence of an inert organic medium vapor. As the inert organic medium, for example, hydrocarbons and ethers are preferably used. Examples of the hydrocarbon include aromatic hydrocarbons such as benzene, toluene and xylene, aliphatic hydrocarbons such as hexane, heptane and decane, and alicyclic hydrocarbons such as cyclopentane, cyclohexane and decalin. Examples of the ether include linear ethers such as diisopropyl ether and isopropyl butyl ether, and cyclic ethers such as tetrahydropyran, tetrahydrofuran and dioxane.
[0008]
In the present invention, the thermal decomposition can be performed under atmospheric pressure, reduced pressure, or increased pressure, but is preferably performed under atmospheric pressure. The thermal decomposition is performed at a temperature of 200 ° C to 600 ° C, more preferably at a temperature of 300 ° C to 500 ° C. The borane complex undergoes thermal decomposition and is deposited on the substrate to give a boron film.
[0009]
The method of the present invention can be carried out as follows.
(1) A gas mixture containing a borane complex and an inert organic medium vapor in an inert gas carrier is generated by bubbling an inert gas through the mixture of the borane complex and the inert organic medium, and then (2) the A method for forming a boron film on a substrate, comprising heating a gas mixture to a temperature of 200 to 600 ° C. to thermally decompose a borane complex contained therein to deposit boron on the substrate. .
In the step (1), the mixture of the borane complex and the inert organic medium is preferably in the form of a solution. The borane complex is preferably adjusted to a concentration of 0.01 to 50% by weight.
[0010]
Passing inert gas through the mixture readily produces a gaseous mixture containing the borane complex and the vapor of the inert organic medium. The inert gas here refers to a substance that has substantially no reactivity with the borane complex as a raw material, and examples thereof include hydrogen, helium, argon, nitrogen, and a mixed gas thereof. Excessive heating during venting is undesirable. The temperature of the mixture during aeration is preferably maintained at 10-50 ° C. During aeration, borane complexes and / or inert organic media can be added to the mixture as needed.
[0011]
The gas mixture obtained in step (1) is then led to carry out step (2) and heated under atmospheric pressure in step (2) to decompose the borane complex. The heating temperature is 200 to 600 ° C. as described above. Boron produced by the decomposition of the borane complex is deposited on the substrate to form a boron film. For the implementation of step (2), the gas mixture can be introduced continuously or intermittently. The introduction time can be appropriately changed depending on the concentration of the borane complex in the gas mixture, the area of the substrate or the thickness of the boron film to be formed. According to the present invention, a boron film can be easily formed with a uniform thickness on a substrate.
The boron film obtained by the method of the present invention is used as a coating material for the inner wall of a nuclear reactor, a standard sample for calibration of an X-ray analyzer, an X-ray detector or an X-ray extraction window in addition to the above neutron detection material. can do.
[0012]
【Example】
EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.
[0013]
Example 1
A toluene solution (2 mol / L concentration) of borane / dimethyl sulfide (BH ₃ .SMe ₂ ) complex was set in the receiver 1 of FIG. 1, and a quartz glass substrate was set inside the heating tube 2. When nitrogen gas was allowed to flow from the gas inlet 3 at a rate of 1 liter / min for 10 minutes while heating the heating tube 2 to 400 ° C., a thin film having a metallic luster was formed on the quartz substrate. When the ESCA spectrum of the thin film having metallic luster was measured, only a peak attributed to the 1s orbital of the boron atom was observed at 189 eV, and no other elements derived from the raw materials such as oxygen, carbon and sulfur were detected. The ESCA spectrum is shown in FIG. The film thickness of this boron film was 120 nm as measured by α step (manufactured by Tencor).
[0014]
Example 2
Instead of the borane / dimethyl sulfide (BH ₃ .SMe ₂ ) complex toluene solution used in Example 1, a borane / pyridine (BH ₃ .Py) complex pyridine solution (1 mol / L concentration) was used. In the same manner as in Example 1, a thin film having metallic luster was formed on a quartz substrate. From the ESCA spectrum of this thin film, only boron atoms were detected, and no elements derived from the raw materials such as carbon atoms and nitrogen atoms were detected.
[0015]
【The invention's effect】
According to the present invention, a boron film can be efficiently formed on a substrate, for example, with a high yield and a high formation rate with a simple operation and apparatus.
[Brief description of the drawings]
FIG. 1 is a schematic explanatory diagram of an apparatus used in Example 1 for carrying out the method of the present invention.
2 is an ESCA spectrum diagram of the boron film obtained in Example 1. FIG.

Claims (2)

A method for forming a boron film on a substrate, which comprises pyrolyzing a borane complex at a temperature of 200 to 600 ° C. in the presence of an inert organic medium vapor. An inert gas is bubbled through the mixture of borane complex and inert organic medium to form a gas mixture containing the borane complex and inert organic medium vapor in an inert gas carrier, and then (2) the gaseous mixture is A method for forming a boron film on a substrate, comprising heating the substrate to a temperature of 200 to 600 ° C. to thermally decompose the borane complex contained therein to deposit boron on the substrate.

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