JPH08325096A - Chemical vapor deposition device - Google Patents

Abstract

PURPOSE: To provide a CVD device capable of suppressing an unwanted competing reaction and capable of growing a thin film having a desired composition from various materials. CONSTITUTION: This device is provided with a chamber 12 housing a substrate 14 and into which a chemical species necessary to chemical vapor deposition is introduced, a light source 20 to introduce a light emitted from a synchrotron into the chamber 12, a filter 19 for selecting a light of specified wavelength from a continuous spectral light emitted from the light source 20 and introducing the light into the chamber and a magnetism generating means 21 to impress a magnetic field in a specified direction on the chemical species in the chamber 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chemical vapor deposition (CVD) apparatus, and more particularly to a CVD apparatus applied for growing a thin film of diamond or the like.

[0002]

2. Description of the Related Art Conventionally, in a CVD apparatus, various excited species are collectively produced in a reaction vessel, and a thin film is formed in competition with various excited species. For example, in plasma CVD, when a thin film of A is grown from a molecule AB on a substrate, in the plasma, A ⁺ , B ⁺ , AB ⁺ , A ⁻ , B ⁻ , e ⁻ , A radicals generated from AB are generated. ,
B radicals and the like are dissociated and generated, and as a result, the thin film of A is preferentially grown.

However, during the thin film growth process, A ⁺ ,
While the A ⁻ and A radicals collide with the substrate to grow a thin film of A, the collision reaction between A and other dissociated species, for example, B ⁺
It is considered that there is a reaction that inhibits thin film formation, such as the production of AB ⁺ due to the reaction between A and A and the production of A ⁻ due to the reaction between e ⁻ and A. At present, it is considered that the reason why the thin film formation is not always successful by CVD for many materials is due to the competitive reaction as described above.

As described above, in the conventional CVD apparatus, it was difficult to form a thin film of a certain material or to form a thin film having a single composition.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a CVD apparatus capable of suppressing an undesired competitive reaction and capable of growing a thin film having a desired composition for various materials. is there.

[0006]

SUMMARY OF THE INVENTION A chemical vapor deposition apparatus according to the present invention is an apparatus for performing chemical vapor deposition of a desired material on a predetermined base material, in which the predetermined base material is accommodated and the desired material is chemically vapor deposited. A chamber into which the necessary chemical species are introduced, means for introducing synchrotron radiation into the chamber, and selective extraction of light of a specific wavelength from the continuous spectrum light generated from the synchrotron radiation source. And a magnetic field generating means for applying a magnetic field in a predetermined direction to the chemical species in the chamber,
Selectively irradiating a chemical species in the chamber with light of a specific wavelength in the synchrotron radiation, and /
Alternatively, the method is characterized in that a magnetic field in a predetermined direction is applied to the chemical species in the chamber irradiated with the synchrotron radiation to limit the reactive dissociation species for performing chemical vapor deposition on the substrate.

In the present invention, synchrotron radiation is introduced into the chamber for chemical vapor deposition. Therefore, a synchrotron radiation light source, an optical window for introduction, etc. can be equipped as a means for introduction.

Synchrotron radiation (SR light) is electromagnetic radiation emitted when accelerating electrons near the speed of light are moved in an accelerator having a circular orbit. SR light has a continuous spectrum in a wide band from infrared to X-ray. In particular, the strong continuous spectrum spanning most of the ultraviolet and X-ray wavelength regions is unique to SR light. SR
The light spectrum can be used after being monochromaticized with a diffraction grating or a single crystal. Further, SR light has a higher intensity than conventional extreme ultraviolet light. Further, the SR light has a sharp directivity and has a high polarization property and a pulse structure.

In the present invention, as a means for selectively extracting light of a specific wavelength from the continuous spectrum light generated from the synchrotron radiation source and guiding it into the chamber,
A diffraction grating, a single crystal, a filter, or the like can be used.
Wavelength (energy) selectivity exists in the generation of dissociated species of molecules. Therefore, in order to generate a predetermined dissociated species corresponding to a predetermined molecule, a spectroscope or a spectroscopic means can be used to extract light of a desired wavelength (energy) from the SR light and irradiate the chemical species in the chamber. it can. By irradiating with light of a predetermined wavelength, it becomes possible to selectively generate a specific dissociated species, for example, either radicals or ions, to cause a reaction.

In the present invention, an electromagnet such as a solenoid coil and a permanent magnet can be used as a means for applying a magnetic field in a predetermined direction to the chemical species in the chamber.

[0011]

In the present invention, SR light is used. As described above, SR light has a broadband continuous spectrum and high intensity. Therefore, SR light is very advantageous as an energy supply source for generating the desired dissociated species. SR
By selectively extracting light having a specific wavelength from the light and irradiating the chemical species in the chamber, a specific dissociated species can be selectively generated. For example, when a radical species is required, light having a wavelength that can preferentially generate the radical species may be extracted. The same applies to other dissociated species. By selectively irradiating with light of a specific wavelength, a specific dissociated species can be preferentially generated, whereby CV
Unfavorable competitive reactions in D can be avoided.

Further, as shown in FIG. 1, in the dissociated species generation region 1 containing charged particles such as ions generated by irradiation of SR light and neutral dissociated species such as radicals, for example, as shown by an arrow in the drawing, A right-handed magnetic field can also be applied. In this case, the dissociated species having a negative charge are directed toward the back side of the paper surface, and the dissociated species having a positive charge are directed toward the front side of the paper surface to be directed. On the other hand, neutral dissociated species remain unaffected.

Therefore, for example, as shown in FIG.
With the conductor 2 installed on the y-axis, a current is passed in the y-axis direction, and a magnetic field in the right-hand screw direction is generated around the y-axis, the raw material chemical species 3 for chemical vapor deposition to flow in the z-axis direction. (Eg molecular beam) can be introduced. In this state, -x
Irradiating the chemical species 3 with the SR light 4 in the axial direction energizes the ion species having a positive charge in the + y direction and the ion species having a negative charge in the −y direction. On the other hand, neutral dissociated species such as radical species still flow in the + z direction.

Thus, for example, only the radical species is C
If necessary for the VD reaction, by providing the substrate in the + z direction, it is possible to perform chemical vapor deposition with the necessary dissociative species while avoiding a competitive reaction with other dissociative species. On the other hand, when charged particles are needed, the substrate may be provided in the direction in which the ions are biased by the magnetic field. In the state shown in FIG. 2, when cations are required, the substrate is provided on the right side,
When negative ions are required, the substrate may be provided in the left direction. As a result, about 80% or more of the charged particles can be selectively taken out and participate in the CVD reaction regardless of the initial velocity.

As described above, according to the present invention, the specific dissociated species generated by the irradiation of SR light can be contributed to the CVD reaction with high efficiency of 80% or more, and while avoiding competitive reaction and inhibition reaction, It is possible to form a film having a desired composition.

[0016]

FIG. 3 shows an example of a CVD apparatus according to the present invention. Referring to FIG. 3, CVD apparatus 10 has a vacuum chamber 12. A sample table 13 is provided in the vacuum chamber 12, for example. A substrate 14 for depositing a thin film is placed on the sample table 13. The side wall 12 a of the vacuum chamber 12 is provided with a light inlet 15. A filter 19 is attached to the light inlet 15.

The side wall 12b of the vacuum chamber 12 is provided with an exhaust hole 16 so that the inside of the vacuum chamber 12 can be evacuated by a vacuum pump (not shown) or the like. Further, a raw material gas introduction port 17 is provided on the side wall 12c of the vacuum chamber 12, and the raw material gas can be introduced into the chamber 12 by opening and closing the valve 11.

The apparatus 10 also comprises a synchrotron radiation source 20. The SR light 22 generated from the electron storage ring (SR ring) 18 of the light source 20 enters the vacuum chamber 12 from the light inlet 15 through the filter 19.
The source gas in the chamber is irradiated.

A conductor 21 for forming a magnetic field is provided in the chamber 12. By energizing the conductor 21, a magnetic field is formed according to Ampere's law.

In the apparatus described above, the source gas is made to flow in the z-axis direction shown in the figure, and the current for forming the magnetic field is made to flow in the y-axis direction shown in the figure. On the other hand, SR light is emitted in the -x direction.

In the apparatus shown above, CVD can be performed as follows. After the substrate 14 is placed on the sample table 13, the chamber 1 is moved by a vacuum pump (not shown) or the like.
The inside of 2 is decompressed to 10 ⁻⁷ Torr to 10 ⁻⁵ Torr.
Next, if necessary, the source gas is introduced into the chamber 12 through the source gas inlet 17. Then, SR light 22 is irradiated from the SR ring 18 through the filter 19 to the raw material gas from the light inlet 15. As the filter, a filter capable of cutting a specific wavelength, for example, a wavelength of 200 nm or more can be used.

In the CVD, dissociation species are generated by light in the vacuum ultraviolet region (wavelength: about 3 to 3) from the viewpoint of generation efficiency.
00 nm) is preferably used. However, even in this wavelength region, if the wavelength is 1240 / E (nm) (E: ionization energy (eV)) or more, only neutral dissociation can occur, but if it is 1240 / E (nm) or less, ionization is caused. Since neutral dissociation occurs at the same time, the generated dissociated species are ions,
Radicals, electrons, etc. are mixed. Therefore, when radicals are particularly required in CVD, it is desirable to select light having a wavelength at which neutral dissociation occurs in the source gas while ionization does not substantially occur. For example, when hydrogen and methane are used as source gases for forming a diamond thin film and CH ₃ radicals are to be selectively generated,
The excitation wavelength for generating ₃ radicals is 1240 / E (n
m) or less, and it is preferable to use a wavelength such as 83 nm.

In the above-described apparatus, by extracting the source light gas from the SR light at a wavelength capable of preferentially generating radicals, the radicals are preferentially generated in the raw material gas and a magnetic field is generated. , Charged particles generated as by-products can be urged in the y-axis direction. This causes radicals to move in the z-axis direction,
That is, it can be preferentially supplied in the direction of the substrate, and a desired thin film can be formed by the reaction of radicals.

[0024]

As described above, according to the present invention,
In CVD, radicals and charged particles for film formation can be selected, and CVD can be preferentially performed from specific dissociated species. Therefore, the present invention is advantageously applied to all aspects of CVD, such as not only the vapor deposition of materials that have been difficult to perform until now, but also the efficiency of CVD, the control of the composition of the CVD film, the formation of a thin film having a more uniform composition. can do.

[Brief description of drawings]

FIG. 1 is a schematic diagram for explaining the operation of the present invention.

FIG. 2 is a schematic diagram for explaining the principle of the CVD apparatus according to the present invention.

FIG. 3 is a schematic diagram showing an example of a CVD apparatus according to the present invention.

[Explanation of symbols]

 10 CVD device 12 Vacuum chamber 13 Sample stage 14 Substrate 15 Optical inlet 16 Exhaust port 17 Raw material gas inlet 18 SR ring 19 Filter

Claims (1)

[Claims] 1. An apparatus for performing chemical vapor deposition of a desired material on a predetermined base material, wherein the predetermined base material is accommodated and a chemical species necessary for performing the chemical vapor deposition of the desired material is introduced. Chamber, means for introducing synchrotron radiation into the chamber, and means for selectively extracting light of a specific wavelength from the continuous spectrum light generated from the synchrotron radiation source and guiding it into the chamber And magnetic generation means for applying a magnetic field in a predetermined direction to the chemical species in the chamber, and selectively irradiate the chemical species in the chamber with light of a specific wavelength in synchrotron radiation. And / or by applying a magnetic field in a predetermined direction to the chemical species in the chamber irradiated with synchrotron radiation, chemical vapor deposition is performed on the substrate. And limits the reaction dissociation species because, chemical vapor deposition apparatus.