KR20140065901A - Pulsed laser deposition apparatus with separated target and deposition method for multilayer thin film using of the same - Google Patents

Abstract

The present invention relates to a pulse laser deposition apparatus including: a chamber in which a substrate and deposition materials are located, a target which is located in the chamber and rotates the deposition materials while supporting the deposition materials; and a laser generator for irradiating a portion of the target with laser so as to dissolve the deposition materials and to deposit a thin film on the substrate with the dissolved deposition materials, wherein the target supports two or more deposition materials while having physically segmented surfaces by the deposition materials, so that the deposition materials onto which the laser is irradiated are changed as the target rotates. According to the present invention, a multilayered ultrathin film having a predetermined cycle can be very precisely made by simple manipulation only.

Description

[0001] The present invention relates to a pulsed laser deposition apparatus and a thin film deposition method using the pulsed laser deposition apparatus,

The present invention relates to a divided-pulse laser deposition apparatus and an ultra-thin multi-layered structure deposition method using the same, and more particularly, to a pulsed laser deposition apparatus including a divided target, in depositing an ultra-thin multi- The present invention relates to a split-target pulse laser deposition apparatus capable of easily controlling and precisely realizing the composition of a thin film, a material number and a material, and an ultra-thin multi-layer structure deposition method using the same.

The multilayer ultra thin film structure is a multilayer structure of thin films made of different materials and has attracted much attention because of its unique properties in many fields such as ionic engineering and superlattice formation using interfacial phenomenon. For example, if two materials with different elastic moduli are continuously present in a thin film of several nanometers thick, the dislocation generating mechanism does not work and the mechanical strength is greatly increased. If a coating film is formed using the structural material, (JS Koehler, Phys. Rev. B 2 (1970) 547, P. Yashar, SA Barnett, J. Rechner and WD Sproul, J. Vac. Sci. Technol. 2913). As another example, if a multi-layer ultra thin film structure is formed by using a material having the same structure but a difference in lattice size, the material movement due to the interface stress can be accelerated and a remarkable improvement in conductivity can be expected (N. Sata, K. Eberman , K. Eberl, and J. Maier, Nature, 408, 946 (2000)). In addition, when a material having a different band gap is continuously formed, the composition of various devices can be formed by controlling the bandgap. Thus, the multi-layered ultra thin film structure has a wide application range.

A conventional method for realizing a multilayer ultra thin film structure is a method of forming a thin film by using a method such as chemical vapor deposition (CVD), physical vapor deposition (PVD), and molecular beam epitaxy (MBE) A method of forming a thin film of material at an intersection has been used. This is basically a method of sequentially depositing the evaporation material while changing the intersection. In the case of general CVD, it is necessary to form an atmosphere suitable for forming each thin film. In the deposition of one material, a delay time for stabilization is essential, and it is difficult to convert the atmosphere into a short time interval. In MBE or atomic layer deposition (ALD), this part has been improved compared to CVD, but it has a disadvantage that it takes a very long time to realize the thin film because the deposition rate is very low. In the case of PVD, the control of the atmosphere is negligible and the deposition rate is higher than that of ALD and MBE. However, in the process of replacing the deposition material, troubles such as manipulation of the apparatus and manipulation of deposition conditions occur.

As the ultra-thin structure is fabricated, the replacement can be well controlled and the periodicity of the ultra-thin structure may be damaged if the deposition time is not controlled properly. Therefore, there is an attempt to minimize the error by mechanically converting the target to which the deposition material is applied in time by introducing an automated system in this part. However, since thin film deposition is generally performed at high vacuum and high temperature, introduction of complicated mechanical devices is not preferable from the viewpoints of cost and lifetime of the device in the long term, and paradoxically due to time deviations of mechanical devices, ≪ / RTI >

Since the thin film deposition environment is a relatively harsh environment for the machine, unlike the outside, this mechanical process should be simplified as much as possible. Also, it should be user-friendly, that it should operate correctly without any deviation, and that it is not troublesome to operate. In the process of changing the intersection, it is troublesome to operate the apparatus and to manipulate the deposition conditions, and it is difficult to control the replacement as much as the ultra-thin structure is manufactured and the periodicity of the ultra thin structure is disturbed Lt; / RTI >

SUMMARY OF THE INVENTION The present invention has been made to overcome the above problems, and it is a first object of the present invention to provide a pulsed laser deposition method and apparatus capable of precisely realizing a multi- Device.

A second problem to be solved by the present invention is to provide a method of depositing an ultra-thin multi-layer structure by a simple process using a pulse laser deposition apparatus including the divided target.

Accordingly, in order to accomplish the first object of the present invention,

A chamber in which the substrate and the deposition material are located;

A target positioned within the chamber and supporting and rotating the deposition material; And

And a laser generator for depositing a thin film on the substrate from the decomposed deposition material by irradiating a laser to the target portion to decompose the deposition material,

Wherein the target supports two or more deposition materials and has a physical partition surface according to the deposition material so that the deposition material to be irradiated by the laser is changed according to the rotation of the target.

According to an embodiment of the present invention, the pulsed laser deposition apparatus may further include a target rotation motor.

According to another embodiment of the present invention, the target rotation motor may further include a rotation speed adjusting device.

According to another embodiment of the present invention, the target may support 2 to 10 deposition materials applied in a single layer in a compartment.

According to another embodiment of the present invention, the laser generator may further include a single or a plurality of wavelength adjustment devices for adjusting the wavelength of the laser.

According to another embodiment of the present invention, the laser generator may further include a single or a plurality of pulse frequency controllers for adjusting the pulse frequency of the laser.

According to another aspect of the present invention,

a) positioning a target within which a substrate and at least two deposition materials are partitioned and supported;

b) activating a laser generator to irradiate a portion of the target with a laser to decompose the deposition material and simultaneously rotate the target; And

and c) periodically depositing two or more evaporation materials supported on the substrate on the substrate in accordance with the rotation of the target, and depositing the superimposed multi-layer structure.

According to an embodiment of the present invention, the step a) may include the step of applying or depositing two to ten kinds of deposition materials on the surface of the target, respectively, in two to ten compartments.

According to another embodiment of the present invention, the step b) may include adjusting the pulse frequency or wavelength of the laser generated from the laser generator.

According to another embodiment of the present invention, the step b) may include adjusting the rotation speed of the target.

According to the present invention, it is possible not only to realize very precise multi-layered thin film having a constant period by a simple operation, but also to easily implement it by an easy method, and to be usefully used in many fields such as ionic engineering and superlattice formation using interfacial phenomenon .

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a structural view of a split-target pulse laser deposition apparatus according to an embodiment of the present invention; FIG.
2 is a conceptual diagram illustrating a segmented target having a segmented or segmented surface according to an embodiment of the present invention.
3 is an image of a YSZ: GDC ultra-thin multi-layer structure formed according to one embodiment of the present invention.

Hereinafter, the present invention will be described in detail with reference to the drawings of the embodiments referred to.

FIG. 1 is a structural view of a divided-pulse laser deposition apparatus according to an embodiment of the present invention.

The pulsed laser deposition apparatus according to the present invention can easily realize an ultra-thin multi-layered structure with a well-controlled cycle, and includes a chamber 10 in which a substrate and a deposition material are located, A thin film is deposited on the substrate 30 from the decomposed deposition material by irradiating a laser beam onto a rotating target 20 supporting the target 20 and a portion of the target 20 to decompose the deposition material 21, And a laser generator (40), wherein the target (20) supports two or more deposition materials (21), with a physical compartment surface according to the deposition material, The deposition material 21 is replaced.

The chamber 10 is a body including a substrate 30 and a deposition material 21 supported by the target 20 and serves as a reaction chamber for providing a reaction space for deposition of the substrate 30 , The present invention is not limited by the shape or material of such chamber 10, but may be a reaction furnace, preferably in the form of spheres, cylinders, or hexahedrons. It is also possible to implement a pulsed laser deposition apparatus in which the laser generator 40 is incorporated in the chamber 10 so as to integrate the chamber 10 with the laser generator 40, The laser generator 40 may be provided outside the chamber 10 after the laser beam transmission window 13 is provided in the chamber 10. In addition, it is preferable that the chamber is formed so as to be able to set appropriate temperature, pressure, or atmospheric conditions for deposition. In one embodiment, the chamber has a gas inlet 11 and a gas outlet 12, A vacuum environment or an inert gas environment.

In the chamber 10, a target 20 for supporting and rotating the deposition material 21 is included. The laser generated from the laser generator 40 is irradiated to a part of the target 20 so that the deposition material 21 is decomposed into a plasma or a gas due to the energy of the laser and is deposited on the substrate 30. The present invention may be characterized by the partitioning or segmenting of the deposition material 21 embodied in the surface of the target 20. That is, the target supports two or more deposition materials, with a physical compartment surface according to the single layer deposition material 21, so that as the target 20 rotates, the deposition material 21 irradiated by the laser is replaced .

FIG. 2 is a comparison and illustration of a target having a compartment or a divided surface according to an embodiment of the present invention and a conventional target in which such compartments are not implemented. As shown in FIG. 2, according to the present invention, a laser irradiated from a laser generator (a black square is indicated by a laser irradiated portion) may be replaced with a material irradiated according to rotation of the target. According to this feature, the thickness period of the ultra-thin multi-layer structure deposited according to the present invention can be constantly and precisely formed. 2 is only an embodiment of the present invention. However, those skilled in the art of reproducing or implementing the present invention are capable of dividing or dividing two deposition materials as shown in the figure, It is also possible to separate a branch material separately to realize more various thin film deposition.

Further, as is generally understood, the pulsed laser deposition apparatus according to the present invention can further include a target rotation motor 22 and is capable of including a drive shaft 23 for transmitting the rotation of the motor, It is also possible to adjust the rotational speed of the target according to the thickness and cycle of the target thin film by providing a regulating device (not shown). The present invention is not limited by the size, shape or rotational speed of such a target 20 but includes a target that can rotate with a central axis to form a replacement cycle of the deposition material irradiated by the laser as desired Are all included in the scope of the present invention.

The laser generator 40 may be a laser generated as described above and may be any device capable of generating a laser capable of decomposing the evaporation material 21 supported on the surface of the target 20 into gas or plasma, It is possible. For example, a laser having a wavelength of 200 to 400 nm can be generated. As a more detailed example, an argon fluoride (ArF) laser having a wavelength of about 193 nm, a krypton fluoride (KrF) laser having a wavelength of about 235 nm, (XeCl) laser with a wavelength of about 355 nm and a neodymium-yttrium-aluminum-garnet laser (Nd: YAG laser) with a wavelength of about 355 nm. It is also possible to apply pulses of 1 to 20 Hz, preferably 5 to 10 Hz, to these lasers according to the purpose and to implement them singly or as a plurality of wavelength adjusting devices or pulse frequency adjusting devices have. It is also possible to further include a focusing lens (not shown) between the target 20 and the laser generator 40. The inclusion of such a focusing lens may be used to adjust the energy per unit area of the laser I would say.

Hereinafter, a method of depositing an ultra-thin multi-layer structure using the pulsed laser deposition apparatus according to the present invention, in which the period of the deposited multi-layer thin film is precisely controlled, will be described.

The ultra thin film multi-layer structure deposition method according to the present invention is characterized by comprising the following steps.

a) positioning a target within which a substrate and at least two deposition materials are partitioned and supported,

b) activating a laser generator to irradiate a portion of the target with a laser to decompose the deposited material and simultaneously rotate the target; and

c) two or more deposition materials supported on the target are alternately and periodically deposited on the substrate in accordance with the rotation of the target.

As in the characteristics of the target described above, the step a) may include the step of applying or depositing 2 to 10 kinds of deposition materials on the surface of the target, respectively, into 2 to 10 compartments. A non-vacuum process including a doctor blade process, a screen printing process, a spin coating process, a spray coating process and a painting process, which is common in the art, or an electron beam coating process, a sputtering process, a chemical vapor deposition process, an organic metal chemical vapor deposition process, A laser deposition method, and an electrochemical plating method. The present invention is not limited by the method of deposition or application, but includes an ultra-thin multi-layer structure deposition method including a target including the deposition material supported on the physically divided surface, Are all included in the scope of the present invention. The target thus implemented is placed at a desired position in the chamber.

Next, when the laser device is operated as the steps b) and c), a part of the target is irradiated with a laser of an appropriate wavelength and intensity, and the deposition material is decomposed into gas or plasma. It is a feature of the present invention that the decomposed deposition material is gradually deposited on the substrate, and the material to be irradiated with the laser can be periodically replaced by rotating the target. Such rotation can be implemented without restriction as long as the rotation speed of the user can be imparted to the rotation regardless of the configuration or type of the apparatus. Further, additional configurations for the pulsed laser deposition apparatus or the ultra thin film multi-layer structure deposition method not described in the specification of the present invention can be understood as those skilled in the art to which the art or knowledge common in the art can apply will be.

Hereinafter, the present invention will be described in more detail with reference to examples, test examples and drawings of the present invention. It will be apparent to those skilled in the art, however, that the present invention is not limited thereto.

Example  And Test Example  : To support two deposition materials Target  Including pulsed laser deposition ( pulse laser deposition , Below PLD ) Configuration of device and its application

A circular sintered body of yttria-stabilized zirconia (YSZ) and gadolinia doped ceria (GDC), which are typical electrolyte materials of a solid oxide fuel cell, were each divided into two halves, and each target was divided into halves to prepare a two-divided target. The rotation speed of the target was fixed at about 1 rpm, and the pulse frequency of the laser was varied at 5 and 10 Hz, respectively, to form a YSZ: GDC ultra-thin multilayer structure.

Since the deposition rate of YSZ is slower than the deposition rate of GDC, it is confirmed that GDC has a thickness of about 2.8 times that of YSZ and that the thickness of each layer is increased about twice as the laser frequency is doubled (FIG. 3) .

Through this, it was possible to successfully implement a multi - layer structure repeated at an intersection with a single deposition. In the case of YSZ and GDC, it was confirmed that the crystal structure coincided to form an epitaxial multilayer structure in one columnar grain.

Based on the above embodiments and test examples, if the target division is made to be about 3: 1 instead of 1: 1 in the area ratio, a multilayer thin film having YSZ and GDC similar thicknesses can be formed. That is, since the pulse laser deposition apparatus and the ultra thin film multi-layer structure deposition method according to the present invention do not need to replace the target or raw material in the middle, it is possible to easily realize the multi-layer ultra thin film structure continuously. The pulse frequency of the target, the target division ratio, and the number of target divisions, the thickness ratio, the material composition, the repetition period, and the like of the multilayer structure can be precisely controlled. According to the present invention, since this adjustment is realized by a single target, it is possible to easily obtain an ultra-thin multi-layer structure in the form of a very well-preserved periodicity without employing various target replacement devices or methods.

10: chamber 11: gas inlet
12: gas exhaust port 13: laser transmission window
20: target 21: deposition material
22: target rotation motor 23: drive shaft
30: substrate 31: substrate support
40: laser generator

Claims (10)

A chamber in which the substrate and the deposition material are located;
A target positioned within the chamber and supporting and rotating the deposition material; And
And a laser generator for depositing a thin film on the substrate from the decomposed deposition material by irradiating a laser to the target portion to decompose the deposition material,
Wherein the target supports two or more deposition materials and has a physical compartment surface according to the deposition material so that the deposition material to be irradiated by the laser is changed according to the rotation of the target. The method according to claim 1,
Wherein the pulsed laser deposition apparatus further comprises a target rotation motor. 3. The method of claim 2,
Wherein the target rotation motor further comprises a rotation speed adjusting device. The method according to claim 1,
Wherein the target supports two to ten kinds of deposition materials applied as a single layer in a section. The method according to claim 1,
Wherein the laser generator further comprises a single or a plurality of wavelength adjustment devices for adjusting the wavelength of the laser. The method according to claim 1,
Wherein the laser generator further comprises a single or a plurality of pulse frequency adjusting devices for adjusting the pulse frequency of the laser. a) a substrate in the chamber; And a target in which two or more deposition materials are partitioned and supported;
b) activating a laser generator to irradiate a portion of the target with a laser to decompose the deposition material and simultaneously rotate the target; And
c) depositing, on the substrate, two or more deposition materials supported on the target periodically in accordance with rotation of the target. 8. The method of claim 7,
Wherein the step a) comprises applying or vapor-depositing two to ten kinds of deposition materials on the surface of the target, respectively, into 2 to 10 compartments. 8. The method of claim 7,
Wherein the step b) comprises adjusting the pulse frequency or wavelength of the laser generated from the laser generator. 8. The method of claim 7,
Wherein the step b) comprises adjusting the rotational speed of the target.

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