JP3465041B2 - YAG fifth harmonic pulse laser vapor deposition method and apparatus - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-quality epitaxial (single crystal) having a nanometer-dimensional smoothness and thickness.
The present invention relates to a method for producing a thin film and a laminated thin film and an apparatus therefor, more specifically, a semiconductor, a superconductor,
Epitaxial (single crystal) thin films of ceramics such as magnetic materials, dielectrics, normal conductors, and insulators, metal oxides, metal-based, inorganic and organic compound-based electronic / magnetic / optical materials, and strength / protective materials The present invention relates to a method and an apparatus for producing a crystalline thin film, an amorphous thin film, a laminated thin film thereof, an artificial lattice, an electronic / magnetic thin film element, a reinforced thin film and a protective thin film.

[0002]

2. Description of the Related Art As a thin film forming method for various materials, there are a pulse laser vapor deposition method, a sputtering method, a heating vapor deposition method using a K cell or an electron beam, a plasma CVD method and the like. Of which
The pulsed laser deposition method can be applied to both inorganic and organic materials, and its film formation is possible even under oxygen pressure. It is easy to precisely control the composition ratio of the constituent elements in the film, and the film formation rate is fast. Have. For that purpose, it is necessary to prepare devices for the production of strong electron-correlation-type metal oxides and compounds such as copper oxide-based high-temperature superconductors with complex element composition ratios and manganese-based oxide giant magnetoresistive substances. Suitable as a membrane method. However, the laser vapor deposition method has a drawback in that surface particles are easily generated, which is the biggest problem to be solved.

In addition, three-terminal devices such as high-temperature superconductor field effect transistors, Josephson coupling devices, next-generation electronic and magnetic thin film devices such as spin valve magnetic heads of ceramic giant magnetoresistive materials and tunnel transistors. For development, it is necessary to achieve the production of high-quality epitaxial (single crystal) thin film having nanometer-dimensional smoothness and thickness, and stacking of the thin films. However, none of the conventional methods has been able to produce such high-quality single crystal thin films and laminated thin films due to the precipitation of surface particles, etc., so that they have not yet been used in industry.

In the pulsed laser deposition method, it is expected that a better quality film can be produced by using a laser beam having a shorter wavelength. Therefore, argon fluoride (ArF) or 24 having a wavelength of 193 nm is used.
Ultraviolet excimer gas lasers such as 9 nm krypton fluoride (KrF) have been mainly used and studied, but have not yet completely suppressed surface particles. Nd:
A solid-state laser such as YAG has a fundamental wave (1064 nm), a second harmonic (532 nm), a third harmonic (355 nm),
The wavelength can be changed using a nonlinear crystal for generating the fourth harmonic (266 nm) and a harmonic. When using up to the third harmonic of the related art, many surface particles were used and a good quality crystal thin film was not produced.

The present inventors have determined that the Nd: YAG fourth harmonic
Depending on the laser deposition method used, NdBa₂ Cu₃ Oy and YB
a₂Cu₃ Oy high temperature superconductor and La_1-x Pbx Mn
O₃ Conducted research on thin film formation of magnetic material and greatly created surface particles
Although the width is suppressed, this is due to the following reasons.
Have come to be certified. That is, in laser vapor deposition, the target
Decomposes materials with intense pulsed light and controls them to a constant temperature
To reconstruct the crystal lattice of the material by colliding it with the substrate
However, two of photolysis and thermal decomposition are involved in the decomposition.
To do. 1) Highest possible photon for the production of good quality films
Use laser light with energy (hence short wavelength)
The target material once, atoms, ions or small
It is necessary to decompose as much as possible into fine particles such as stars
On the other hand, 2) the light absorbed by the substance is converted into heat.
And the thermal decomposition of the substance caused by the local heat is large
The particles pop out, which prevents the growth of smooth thin films on the substrate.
To avoid this, a narrow pulse width
It is necessary to use a laser. Our research shows that
The light was changed from 3rd to 4th harmonic to short wavelength light
And YAG solid-state laser is more efficient than excimer gas laser.
The width of the space is narrow (1 / 3-1 / 5)
As a result, the contribution of thermal decomposition was reduced.
As a result, the number of surface particles has been reduced, and shorter wavelengths have been achieved.
The fifth harmonic of solid-state laser such as YAG is required for the film formation method
If it can be generated at a very high output, it will reduce the generation of surface particles
Acknowledged that it is possible to produce high quality single crystal thin film
It was.

[0006]

In order to suppress the generation of surface particles for the development of electronic and magnetic devices and to manufacture high quality crystalline thin films and laminated thin films having a nanometer-dimensional smoothness, With a narrow pulse width, it can oscillate laser light in the shortest possible wavelength of ultraviolet light and vacuum ultraviolet light, and it is simple and
There is a need for a method and a device that meet various industrial technical requirements such as safety and low running cost. Further, in order to vaporize an inorganic material by a pulse laser method to form a high quality thin film, usually, an output energy of several tens mJ / pulse, at least about 10 mJ / pulse, and a short pulse width of several nanoseconds are required. Continuous and stable oscillation of a pulsed laser beam having, is required. Some excimer lasers have short wavelengths (oscillation frequency of 193 nm) like ArF lasers, but these lasers have a long pulse width (tens of nanoseconds), and they also contain toxic and corrosive halogen gases such as fluorine and chlorine and argon. Since an expensive ultra-high-purity noble gas such as or xenon is used, there are problems in industrial technology such as low cost, safety, and cost. In addition, the ArF laser having the shortest wavelength has a particularly high erosive property, so that there is a problem that the laser output greatly decreases with time. Therefore, there are no problems in industrial technology such as the use of toxic and erosive halogen gas, and a stable pulse laser light source with a short wavelength and a short pulse width and a thin film or a laminated thin film by laser vapor deposition using it A manufacturing method and a device are required.

The present invention has been made in order to solve the above technical problems, and uses N nonlinear optical crystals.
The fifth harmonic (wavelength: 213 nm) that has a short wavelength and a short pulse width and has sufficient output energy and stability necessary for vapor deposition by combining the fundamental wave and higher harmonics of a pulsed laser such as d: YAG. ) Is efficiently generated and the generation of surface particles due to pulsed laser deposition using the same is suppressed, and a method for manufacturing a high-quality crystal thin film and a laminated thin film, and a manufacturing apparatus capable of embodying the method are provided.

[0008]

The present invention for solving the above-mentioned problems comprises the following technical means. That is, the thin film manufacturing method according to the present invention uses the fourth harmonic (wavelength 266 nm) and the fundamental wave (wavelength 1064 nm) of pulsed laser light such as Nd: YAG or the third harmonic (355 n).
m) and the second harmonic (533 nm) are combined by a non-linear optical crystal, and the fifth harmonic (wavelength 21)
3 nm) is generated efficiently, and further, the first step of separating only the fifth harmonic from the laser light in which these three lights are mixed by the spectroscopic means, and the temperature of the inorganic single crystal substrate or glass substrate is set and The target is set in advance in a vacuum chamber that has a substrate holder with a controllable heater and a target holder that can set the target of inorganic or organic material to be used for thin film production, and that can exhaust to low pressure or vacuum. Then, the dispersed fifth harmonic is focused on the target by using a lens and irradiated, and the target material is decomposed in a pulse to be evaporated, and the target material is allowed to collide with the substrate as it is or through a device pattern mask. The steps and steps are performed a predetermined number of times to produce a crystalline or amorphous thin film of the substance or a thin film of the element pattern. It is an butterfly.

In the method for producing a laminated thin film according to the present invention, a plurality of targets are previously set in a vacuum chamber provided with a target holder capable of setting a plurality of targets and the substrate holder. Incidentally, the process of performing the first step and the second step for a predetermined number of pulses is sequentially performed for each target, and a thin film of those substances or a thin film of an element pattern is sequentially formed on the substrate. It is characterized by being manufactured by stacking on.

Further, the thin film producing apparatus according to the present invention is
A fifth harmonic that can efficiently generate a fifth harmonic by combining a fundamental wave of pulsed laser light such as Nd: YAG and various harmonics with a non-linear optical crystal, and can separate only the fifth harmonic by spectral separation. Wave generation means, variable focusing means for irradiating the target with varying degree of focusing by a lens capable of transmitting short-wavelength ultraviolet rays, inorganic inorganic crystal substrate, glass substrate, etc. A vacuum chamber provided with a controllable substrate holder with a heater, a target uniform evaporation means such as a target rotating mechanism for uniformly evaporating a target, and a mask for forming an element pattern, if necessary. It is characterized by comprising means, etc.

In addition, the apparatus for producing a laminated thin film according to the present invention includes means for generating the fifth harmonic wave, variable focusing means for irradiating the fifth harmonic wave, substrate holder and target uniform evaporation means, and various means. A target position moving mechanism capable of setting a plurality of targets of substances or materials and sequentially moving each target to a laser beam focusing irradiation position, and a vacuum chamber provided with a mask means, if necessary, It is characterized by consisting of.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described in more detail. The non-linear optical crystal is K ₂ HPO ₄ (dipotassium hydrogen phosphate: DKHP or its deuterium compound: DKD
P), BaB ₂ O ₄ (barium borate salt: BBO), KTiOPO ₄ (potassium phosphate titanate: KTP), etc., the magnitude of the refractive index of light differs depending on the crystal orientation (that is, the magnitude and direction). Has an anisotropy represented by a tensor amount such as a spheroid, which has the property of changing with the wavelength λ of light (hence, frequency ν). Therefore, there exists a crystal direction with the same refractive index for two lights with different wavelengths (frequency is νi and νj), and when both the strong lights are incident in that direction, they are combined by two-photon absorption. Generated harmonic (frequency νc = νi + νj) is generated. The converted output of these crystals is not proportional to the intensity of incident light, but increases non-linearly (nth-order function; n: non-linear coefficient). If a nonlinear optical crystal such as BBO that transmits light in a region close to vacuum ultraviolet rays is used, it is possible to generate higher-order laser harmonics close to vacuum ultraviolet rays.

Next, regarding the present invention, a high output YAG first
NdBa by 5 harmonic pulse laser deposition₂ Cu₃ O
y (neodymium 2 barium 3 copper oxide) superconductor and La
_1-x PbxMnO₃ Thin films of magnetic materials and YBa₂ 
Cu₃Oy (yttrium 2 barium 3 copper oxide) and C
eO₂ As an example, the preparation of laminated thin film with (cerium oxide)
This will be specifically described.

In the YAG fifth harmonic pulse laser, a BBO crystal was used for the fifth harmonic oscillation. Since the non-linear optical characteristics greatly depend on the quality of the crystal, a BBO crystal that is uniform and has no defects or distortions was selected and used, but the present invention is not limited to this.
As a crystal that transmits light up to a short wavelength of 213 nm or less of the fifth harmonic and has nonlinear optical characteristics, for example, Li
B ₃ O ₅ (LBO), Sr ₂ Be ₂ B ₂ O ₇ (SBB
O) or KBe ₂ BO ₃ F ₂ (KBBF) can also be used. Here, a commercially available Nd: YAG laser device that can oscillate from the fundamental wave to the second, third, and fourth harmonics was used as the original laser light source. This device uses a DKDP nonlinear optical crystal for harmonic generation. The YAG
In the fifth harmonic pulse laser, a BBO crystal was used to combine (4 + 1) the fourth harmonic and the fundamental wave to generate the fifth harmonic. Note that the fifth harmonic can be similarly generated by combining (3 + 2) the third harmonic (355 nm) and the second harmonic (533 nm), but the nonlinear coefficient in the case of 4 + 1 combination is n = In the case of 3 + 2 coupling, which is 2.7, which is low, n = 1.4, so the fourth harmonic and the fundamental wave were coupled.

In order to cause this coupling, the polarization direction of the fourth harmonic is changed to the polarization direction of the fundamental wave (vertical polarization: V polarization).
Second, which is included in the laser light and becomes an obstacle.
It was necessary to remove harmonics (wavelength 532 nm). Therefore, first, the direction of the DKDP crystal for generating the second harmonic of the Nd: YAG laser device is changed to shift the polarization direction of the second harmonic by 90 degrees from the fundamental wave to obtain horizontal polarization (H polarization). The orientation of the DKDP crystal for generating the fourth harmonic was changed to oscillate the fourth harmonic having the same polarization direction (vertical) as the fundamental wave. Thus, by making only the disturbing second harmonic into its horizontal polarization, it was possible to cut or attenuate it by using a dichroic mirror or high-purity quartz for ultraviolet rays cut at Brewster's angle. Next, a BBO crystal (uniaxial crystal; a = b = c, α = β = γ ≠ 90 °)
It was used to generate the fifth harmonic by combining the fourth harmonic and the fundamental wave, but the phase matching angle was θ = 51.1 degrees, so it was cut to the same angle before use. Since the allowable angle Δθ of the phase matching angle is about 0.13 mrad, it is necessary to cut out extremely accurately. In this way, the wavelength-converted laser light contains not only the unconverted fundamental wave and the fourth harmonic, but also a small amount of the second harmonic, so it is separated by a prism, and these lights are guided to a terminator for absorption and excluded. By doing so, it was possible to finally obtain the pulsed laser light of only the fifth harmonic.

In the Nd: YAG laser device used here, the output of the fundamental wave is 800 mJ / pulse and the output of the fourth harmonic is 100 mJ / pulse at the maximum, but the above optical system is constructed and optimized. As a result of adjustment, maximum 22 mJ /
It became possible to generate the fifth harmonic of high output of the pulse. If you use a higher output YAG laser
Can generate harmonics. From the conventional research, when a crystalline thin film is produced by laser deposition using the fourth harmonic of a YAG laser, it depends on the target compound, but at least 15
It was found that a laser energy of about -25 mJ / pulse or more is required. Therefore, in order to avoid output attenuation due to light absorption and scattering / reflection as far as possible, even if the direction of the fifth harmonic laser light after spectroscopy is not changed by using a mirror on the way, only one lens is used for the chamber. A chamber for laser vapor deposition film formation was prepared in which the laser direction and the target were linearly opposed to each other so that they could be focused on the target material inside and made incident. The lens was also antireflection coated (AR) coated to eliminate light loss.

At the time of film formation, the chemical bond of the target material is broken by the irradiation of the pulsed laser light, and atoms such as constituent elements, ions and particles such as various clusters are instantaneously generated, which is called an ablation plume. A plasma-state flame is generated, which impinges on the substrate and reconstructs and forms a thin film of the material on the substrate. In the case of an oxide, oxygen is lost due to bond cleavage, so ablation is performed under low oxygen pressure at low pressure. In this evaporative flame, the particles collide with oxygen to cause an oxidation reaction. The quality and electromagnetic characteristics of the thin film depended largely on the energy and the degree of oxidation of the particles in the evaporative flame during film formation, and thus on the shape, size and color of the evaporative flame. Therefore, a film was formed by using a lens and changing the degree of focusing of laser light on the substance. It was possible to form a film with good reproducibility by setting the optimum conditions. Also, YB
In order to prepare a crystal laminated thin film of a ₂ Cu ₃ Oy and CeO ₂ , it was necessary to put both targets in a vacuum chamber from the beginning and perform vapor deposition by sequentially changing the targets without breaking the vacuum.

On the basis of these facts, the YAG fifth harmonic pulsed laser deposition method is more suitable for the construction of the manufacturing means and the optimization of the conditions as compared with the conventional method because of the generation of the high power fifth harmonic wave. However, once constructed and optimized, it has been demonstrated that thin films and laminated thin films with reduced surface particles can be produced with good reproducibility, and it can be a technology that can be used in industry. It became clear. The present invention is not limited to the Nd: YAG pulse laser described above, and any pulse laser light having the same effect can be used.

[0019]

Embodiments of a laser generating method, a thin film / laminated thin film manufacturing method, a laser generating apparatus, and a thin film / laminated thin film manufacturing apparatus according to the present invention will be described below with reference to the accompanying drawings.

1 and 2 are schematic views showing a laser generator 0 embodying the laser generating method and the thin film / laminated thin film manufacturing method according to the present invention, and the structure of the thin film / laminated thin film manufacturing apparatus 1. It is a schematic diagram showing. The laser generator 0 and the thin film / laminated thin film manufacturing device 1 are Nd: YA
A pulse laser generator 2 capable of generating a fundamental wave and a fourth harmonic of a laser such as a G laser with the same polarization direction;
Second harmonic attenuator 3 for reducing or cutting the second harmonic, nonlinear optical crystal 4 for coupling the fourth harmonic and the fundamental wave to generate the fifth harmonic, the fifth harmonic and other lasers A spectroscopic means 5 for separating light, an absorbing means 6 for absorbing other than the fifth harmonic, a converging / irradiating means 7 for converging and irradiating the target with the fifth harmonic, and a crystal or glass substrate are set to a high temperature. The substrate holder 8 with a heater capable of controlling the temperature of the substrate and its linear introduction mechanism 9, the target holder 10 on which a plurality of targets can be set, and the plurality of targets are sequentially moved to a laser irradiation position. A target position moving mechanism 11, a uniform evaporation mechanism 12 such as a target rotation mechanism, and a mask 13 for forming a thin film in a pattern of an element pattern are provided, and a low pressure is applied by a vacuum pump 14. A vacuum chamber 15 that can be evacuated to a vacuum, consisting of.

The pulse laser generator 2 generates a high-power fifth harmonic wave capable of forming a film by laser vapor deposition, so that the fundamental wave and the fourth harmonic wave are 800 and 1, respectively.
An Nd: YAG pulse laser having an output of about 00 mJ / pulse was used. The second harmonic wave attenuating means 3 is a dichroic mirror that reflects only the second harmonic wave, or a high-purity quartz rod cut into Brewster angles so as to reflect only the horizontally polarized second harmonic wave. The nonlinear optical crystal 4 is made of BBO, LB cut to a predetermined polarization matching angle.
O, SBBO, or KBBF single crystal was used. The spectroscopic means 5 for separating the fifth harmonic wave is a prism made of high-purity quartz or a spectroscopic mirror that transmits up to near vacuum ultraviolet rays. Further, the absorbing means 6 for absorbing other than the fifth harmonic is an optical filter or the like. Further, the means 7 for collecting the fifth harmonic and irradiating the target with a target is a lens made of high-purity quartz or the like.

Since the substrate holder 8 optimizes the distance between the target and the substrate as one of the conditions when optimizing the film forming conditions, it is provided with a straight line introducing mechanism (terminal) 9 for changing the distance. I decided to do it. Further, the target holder 10 is not limited to the production of one thin film, but a plurality of (A,
B, C, etc.) and step motor drive to move the target sequentially to the position where the fifth harmonic pulsed laser light is focused and irradiated so that the thin films can be sequentially laminated. The target position moving mechanism 11 and the target uniform evaporation mechanism such as the target rotation mechanism 12 driven by a motor for avoiding the damage of the target by concentrating the laser light at one point. The mask 13 has a plurality of component pattern holes sequentially formed in an elongated flat plate in order to form a device by laminating thin films having various patterns (figures / shapes). Laser ablation of each target material is performed, or the mask is operated from the outside of the chamber so that each pattern hole comes to the location of the laser flame. The film for patterning was to be sequentially produced by transfer and laminated, and was used as a transfer mask made of Inconel alloy or the like so as to withstand high temperature and oxidation conditions. Further, since the vacuum pump 14 needs to optimize the conditions by changing the oxygen pressure at a low pressure in the case of forming a thin film of a metal oxide-based electronic / magnetic material by laser deposition, it is necessary to use a solenoid valve or the like. The pressure control system 14a is provided.

Next, the laser vapor deposition thin film constructed as described above is used.
Generation of fifth harmonic and NdBa using film forming equipment₂ Cu
₃ Crystal thin film of Oy superconductor and YB using mask
a₂ Cu₃ Oy superconductor and cesium oxide (CeO₂ )of
The production of a laminated thin film will be described as an example.

From the pulse laser generator 2, the fourth harmonic,
After passing the Nd: YAG pulsed laser light including the second harmonic and the fundamental wave to the second harmonic attenuating means 3, the fourth harmonic and the fundamental wave are combined by using the nonlinear optical crystal 4 to obtain the fifth harmonic. Generated harmonics. Next, the spectroscopic means 5 using a prism
And the absorption means 6 absorbs all but the fifth harmonic wave
Only harmonics were used. FIG. 3 shows spectra of laser light before and after the generation of the fifth harmonic. FIG. 3A shows laser light before coupling, in which the fourth harmonic, the second harmonic, and the fundamental wave are mixed. FIG. 3B shows the spectrum of the fifth harmonic laser after being generated and dispersed. Spectroscopy Another fifth harmonics in the spectrum (lambda _5), twice the wavelength and 3 times the line in the wavelength position (2 [lambda] _5, 3 [lambda] ₅₎ it is, which is using the grating (diffraction grating) The fifth harmonic wave is only diffracted to that position because it is measured by the meter, and the laser light is only the fifth harmonic wave.

A target such as a disc-shaped NdBa ₂ Cu ₃ Oy superconductor was set in the target holder 10 in the vacuum chamber 15. The target is rotated by the target rotation mechanism 12 for preventing the laser light from concentrating on one point and damaging the target. Washed SrTiO ₃ (STO) and LaAlO ₃
The —SrAlTaO ₆ (LSAT) single crystal substrate was set on the substrate holder 10 with a heater, and the vacuum chamber was once evacuated to a high vacuum. After cleaning the substrate surface by raising the substrate temperature to about 800 ° C, the temperature is set to a predetermined value (50
0-800 ° C.), then a small amount of ultra-high purity oxygen is introduced into the vacuum chamber, and the pressure control system 14a connected to the vacuum pump 14 is adjusted to obtain a predetermined oxygen pressure (0.1-1). It was set to about 0.0 Torr).

After performing the above operation in advance, the vacuum chamber 1 is irradiated with the fifth harmonic by the focusing and irradiating means 7 of the quartz lens.
The target on the target holder 10 in FIG. 5 is focused and irradiated, and the target material is ablated toward the substrate in a pulsed manner, and N is placed on the substrate set in the holder.
A crystalline thin film of dBa ₂ Cu ₃ Oy was prepared. At the time of film formation, in addition to the conditions in the ordinary laser vapor deposition method, that is, various conditions such as substrate temperature, oxygen pressure, and laser frequency, the conditions associated with the fifth harmonic pulse laser vapor deposition method, that is, YA
Output of fourth harmonic of G laser, orientation of nonlinear optical crystal,
The concentration of the fifth harmonic pulsed laser light on the target was optimized.

The characteristics of the crystalline thin film (a) of the NdBa ₂ Cu ₃ Oy superconductor produced by the experiment of the fifth harmonic pulse laser deposition method and the conventional laser deposition method using the YAG fourth harmonic were used. A comparison with the characteristics of the produced thin film (b) is shown in FIGS. 4, 5 and 6. FIG. 4 shows the temperature dependence of the electric resistance. The superconducting transition temperature Tc of the thin film manufactured by the fourth harmonic is about 78K, whereas the Tc is 84K when manufactured by the fifth harmonic, which is a great improvement, and the method is of higher quality. It can be seen that a thin film is produced.

As shown in the X-ray diffraction spectrum of the thin film of FIG. 5, (h00); h of the SrTiO ₃ crystal used as the substrate for both the films prepared by the laser deposition methods (a) and (b).
Other than the X-ray diffraction line of = 1-4, mainly NdBa ₂ Cu ₃
It is composed of the (00l); l = 1-13 diffraction spectrum of the Oy superconducting crystal. However, in the thin film of (a), the signal intensity of the diffraction line is stronger, the line width is narrower and sharper, and the diffraction lines higher than 1 = 10 are clearly separated by the Kα1 and Kα2 X-rays. Further, in (a), SrTiO 3
_While the spectrum is only for the ₃ crystal substrate and the NdBa ₂ Cu ₃ Oy crystal, in (b) there are also diffraction lines due to other impurities. Both of these facts indicate that a c-axis oriented single crystal thin film is produced, but the film of (b) is poor in quality due to the presence of impurity particles, and (a) is a higher quality crystal film. Shows.

Further, as shown in the high magnification optical microscope photograph (inner scale: 10 μm) of the thin film surface in FIG. 6, NdBa ₂ Cu ₃ O produced by the conventional fourth harmonic pulse laser deposition method.
In the y film (b), innumerable surface particles are generated, whereas in the film (a) produced by using the fifth harmonic, the number of impurity surface particles is significantly reduced. From the above,
It can be seen that in the fifth harmonic pulsed laser deposition method, the generation of surface particles is suppressed and the film quality is improved.

The photograph of FIG. 7 (see FIG. 8 of the explanatory diagram) is
By the fifth harmonic pulsed laser deposition method, SrTiO ₃
On a single crystal substrate, 1) YBa ₂ Cu ₃ was formed by using a mask pattern having 1 mm wide slender linear holes in the diagonal direction.
A thin film pattern of Oy superconductor is formed, 2) Then, CeO ₂ is formed in a square pattern of 3 mm square,
3) Finally, using a mask pattern having the same shape as the above 1) but oriented in the direction perpendicular to the above 1), YBa ₂ Cu _{3 is} again added.
YBa ₂ Cu ₃ Oy / CeO ₂ / YBa ₂ Cu ₃ produced by forming a thin film pattern of an Oy superconductor
The Oy 3-layer laminated element is shown. Further, FIG. 9 is an X-ray diffraction spectrum of the three-layer laminated element. (H00) of the SrTiO ₃ crystal used as the substrate; (00) of the YBa ₂ Cu ₃ Oy superconducting crystal other than the X-ray diffraction line of h = 1-3.
l); l = 1-11 and CeO ₂ crystal (h00); h =
Since it consists of only 2 and 4 diffraction spectra,
YBa2 Cu ₃ it can be seen that Oy / high-quality crystal multilayer thin film having a CeO ₂ of c-axis orientation is produced.

[0031]

As described above, the laser generation and thin-film and laminated thin-film manufacturing apparatus and method according to the present invention are
An efficient system for generating a high-power fifth harmonic pulsed laser beam, a variable focusing system for irradiating the target while changing the degree of its focusing, and a vacuum chamber system are organically combined. , High quality Nd with nanometer-dimensional smoothness and thickness, which can significantly suppress the generation of impurity surface particles, which could not be produced by the conventional YAG fourth harmonic.
It enables the production of crystal thin films and laminated thin films of materials such as Ba ₂ Cu ₃ Oy and YBa ₂ Cu ₃ Oy.

Moreover, this laser vapor deposition method does not depend on the material of the thin film to be produced or the kind of substance. That is, as long as a target can be prepared, it does not depend on whether it is an inorganic material or an organic material, and it is a metal oxide system such as a semiconductor, a dielectric, a superconductor, a magnetic body, a conductor, an insulator, a metal system or a compound system. The crystalline thin film can be prepared for any of the above, and high-quality multi-layer laminated thin films can be prepared by changing the target position sequentially. Also, by using a mask pattern, the thin film element structure of various patterns can be produced. It is possible to produce a laminated thin film element having

[Brief description of drawings]

FIG. 1 is a schematic diagram of a generator for a fifth harmonic pulse laser.

FIG. 2 is a schematic view of an apparatus for producing a thin film and a laminated thin film by a pulse laser deposition method.

FIG. 3 is a laser beam before the fifth harmonic is generated by combining the fourth harmonic and the fundamental wave with a nonlinear optical crystal (a).
And the spectrum of only the fifth harmonic laser light after being generated and dispersed (b).

FIG. 4 is a thin film (b) produced by a laser deposition method using the fourth harmonic of an Nd: YAG laser and NdBa ₂ Cu produced by a pulse laser deposition method using the fifth harmonic.
_This is the temperature dependence of the electrical resistance of the ₃ Oy superconducting crystal thin film (a).

FIG. 5 is a thin film (b) produced by a laser deposition method using the fourth harmonic of an Nd: YAG laser and NdBa ₂ Cu produced by a pulse laser deposition method using the fifth harmonic.
_{3 is} an X-ray diffraction spectrum of a ₃ Oy superconducting crystal thin film (a).

FIG. 6 is an optical micrograph of the surface of a NdBa ₂ Cu ₃ Oy superconducting crystal thin film (a) prepared by a pulsed laser deposition method using the fourth harmonic (b) of the Nd: YAG laser and the fifth harmonic. Is.

FIG. 7: Y produced using a mask by a pulsed laser deposition method using the fifth harmonic of an Nd: YAG laser
Ba ₂ Cu ₃ Oy / CeO ₂ / YBa ₂ Cu ₃ Oy 3
6 is a photograph of a laminated thin film having a layer laminated device structure.

8 is an explanatory diagram of FIG. 7 described above.

FIG. 9: YBa ₂ Cu ₃ Oy / produced by a pulsed laser deposition method using the fifth harmonic of an Nd: YAG laser
_{3 is} an X-ray diffraction spectrum of a CeO ₂ / YBa ₂ Cu ₃ Oy _three- layer laminated thin film.

[Explanation of symbols] 0th harmonic generator 1 Thin film and laminated thin film production equipment 2 pulse laser generator 3 Second harmonic attenuation means 4 Nonlinear optical crystal 5 Spectral means Absorption means other than the 5th harmonic 7 Focusing irradiation means 8 Substrate holder with heater 9 Straight line introduction mechanism (terminal) 10 target holder 11 Target position moving mechanism 12 Uniform evaporation mechanism such as rotation mechanism of target 13 masks 14 Vacuum pump 15 chambers

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Claims (4)

(57) [Claims] 1. A fifth harmonic having a shorter wavelength by combining the fourth harmonic and the fundamental wave of Nd: YAG pulsed laser light or the third harmonic and the second harmonic with a nonlinear optical crystal. The first step of generating a wave and further separating only the fifth harmonic by the spectroscopic means from the laser light in which the three lights are mixed, the substrate holder with a heater that can set the substrate and control the temperature, and the thin film Equipped with a target holder that can set the target (target substance) to be manufactured, and the lens that has the fifth harmonic wave dispersed into the target that has been set in advance in a vacuum chamber that can exhaust to low pressure or vacuum Concentrate and irradiate on the target using a pulse, decompose the target material in a pulse and evaporate (ablate), and use it as it is or as a mass for the element pattern. Through a second step of colliding with the substrate through a predetermined pulse number of times until the film thickness is to be made to have a crystalline or amorphous thin film of the material forming the target, or an element pattern. A method for producing a thin film by laser vapor deposition, characterized in that a thin film is produced. 2. A plurality of targets are set in advance in a vacuum chamber provided with a target holder capable of setting a plurality of targets and a substrate holder, and a first step and a second step are prepared. And the film thickness
The target is sequentially subjected to a predetermined number of times until each target, and thin films of those substances are sequentially laminated on the substrate or by passing a mask through the mask. 1. The method for producing a thin film as described in 1. 3. A fifth method in which a fundamental wave of Nd: YAG pulse laser light and various harmonics are combined by a non-linear optical crystal.
A fifth harmonic generation unit that generates a harmonic and separates only the fifth harmonic by splitting the light; a fifth harmonic focusing and irradiating unit that irradiates the target with varying the degree of light focusing; Equipped with a substrate holder with a heater that can be set and whose temperature can be controlled up to a high temperature, and a target uniform evaporation means for uniformly evaporating the target while avoiding damage to the target by concentrating laser light at one point. An apparatus for forming a thin film by vapor deposition, comprising: 4. A data Getto and uniform evaporation means, vacuum Chang having a target holder, and a plurality of targets can load and sequentially moved can target position movement mechanism of each target to the condensing irradiation position of the laser beam <br/> bar, thin-film producing apparatus according to claim 3, characterized in that it comprises a.