KR101687777B1 - Substrate for electronic display device having biaxially textured SnO2-x semiconductor layer and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a substrate for an electronic display device having a tin oxide semiconductor (SnO _{2 -x} , 0 <x <1) layer aligned in two directions and a method of manufacturing the same, So as to form a tin oxide semiconductor layer having excellent conductivity and stability. The present invention relates to an organic electroluminescence (EL) device comprising a glass substrate on which a magnesium oxide (MgO) layer is aligned in two directions and a tin oxide semiconductor (SnO _{2 -x} , 0 <x <1) layer is formed on the magnesium oxide layer in two directions A substrate for a display device and a method of manufacturing the same are provided.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a substrate for an electronic display device having a tin oxide semiconductor layer aligned in two directions and a method for manufacturing the same,

The present invention is an electronic display device, and relates to a method of manufacturing the same, and more particularly, to which tin oxide (SnO ₂₎ the basis of tin oxide semiconductor _{(SnO 2-x, 0 <} x <1) layer is formed to a glass substrate To a substrate for an electronic display device having a tin oxide semiconductor layer aligned in two directions and a method of manufacturing the same.

One of the trends in information technology today is to combine the functions of electronic devices with those of display devices. An electronic display device is one in which these electronic elements and functions are combined with the functions of display elements.

Furthermore, in today's information society, the role of electronic display devices becomes very important, and various electronic display devices are widely used in various industrial fields. [0003] In the field of electronic display devices, electronic display devices having new functions suited to demands of an information society that has been diversified and developed have been continuously developed.

Generally, an electronic display device refers to a device that transmits various information to human beings through the eyes. That is, the electronic display device refers to an electronic device that changes into an optical information signal capable of recognizing an electronic information signal output from various electronic devices by human vision, and is a device that plays a role of bridging between human and electronic devices can do.

In such an electronic display device, when an optical information signal is displayed by a light emission phenomenon, it is referred to as a light emission display device, and when it is displayed by light modulation by reflection, scattering, interference, or the like, it is referred to as a light reception display device.

Examples of such electronic display devices include a cathode ray tube (CRT), a plasma display panel (PDP), an organic electro luminescence display (OELD), a liquid crystal display (LCD) An electrophoretic image display (EPID), a light emitting diode (LED) display device, and an organic light emitting diode (OLED) display device.

Here, the cathode-ray tube display device has the longest history and is used for a television or a computer monitor, and occupies the highest market share in terms of economy and the like. However, it has many drawbacks such as heavy weight, large volume, Have.

2. Description of the Related Art In recent years, with the rapid progress of semiconductor technology, there has been a demand for a flat panel type display device as an electronic display device suitable for a new environment in accordance with the tendency of downsizing, thinning, and lightening of electronic devices along with low voltage and low power consumption of various electronic devices Is rapidly increasing. Accordingly, flat panel type display devices such as a liquid crystal display (LCD), a plasma display (PDP), an organic EL display (OELD), an organic light emitting diode (OLED)

In a liquid crystal display (LCD), a liquid crystal material having an anisotropic permittivity is injected between an upper transparent insulating substrate on which a common electrode, a color filter, a black matrix and the like are formed, a lower transparent insulating substrate on which switching elements and pixel electrodes are formed The molecular arrangement of the liquid crystal material is changed by adjusting the intensity of the electric field formed on the liquid crystal material by applying different electric potentials to the pixel electrode and the common electrode to control the amount of light transmitted through the transparent insulating substrate, As shown in FIG. In such a liquid crystal display device, a thin film transistor liquid crystal display (TFT LCD) using a thin film transistor (TFT) element as a switching element is mainly used.

In particular, an organic light emitting diode (OLED) display device has a better viewing angle and contrast ratio than a liquid crystal display device (LCD) because OLED elements are self-emissive type, and lightweight thin type is possible because no backlight is required, .

In addition, OLED devices are capable of DC low voltage driving, have a fast response time, are resistant to external impact, have a wide operating temperature range, and are especially advantageous in terms of manufacturing cost.

Thus, the OLED device can be used as a pixel of a graphic display, a pixel of a TV image display or a surface light source, and can also be formed on a transparent substrate that can be made of plastic, and has good color. Therefore, an organic light emitting diode (OLED) It is suitable for next generation flat display.

Electronic display devices such as organic light emitting diode (OLED) displays require transparency, high charge mobility, and stability. Therefore, transparent semiconductors and transparent conductors capable of fulfilling their functions as electronic devices while satisfying transparency, and methods of manufacturing them have been actively studied. For example, ITO (Indium Tin Oxide) has been developed and used as such a transparent conductor, and ZnO and the like have been developed as transparent semiconductors, but their stability is low and their applicability as a transparent semiconductor is extremely limited.

Korean Patent No. 10-0719535 (Nov.

In order to solve this problem, a method of utilizing a SnO ₂ -based compound semiconductor (hereinafter referred to as a tin compound semiconductor (SnO _{2 -x} , 0 <x <1)) as an electronic device for an electronic display device is studied . These tin oxide semiconductors have various forms of amorphous polycrystalline and crystalline aligned in two directions.

However, tin oxide semiconductors based on SnO ₂ can form crystals aligned in two directions on a specific substrate, for example, a sapphire substrate having crystal orientation, but amorphous or polycrystalline tin oxide semiconductors are formed only on amorphous glass substrates I have a problem.

As a result, when using SnO ₂ , there is a limitation in applying tin oxide semiconductors based on crystals aligned in two directions to an electronic display device using a glass substrate as a mother substrate.

Accordingly, an object of the present invention is to provide a substrate for an electronic display device in which a tin oxide semiconductor layer aligned in two directions having a suitable charge density and a high charge mobility is formed on a glass substrate, and a method of manufacturing the same.

It is another object of the present invention to provide a substrate for an electronic display device in which a tin oxide semiconductor layer aligned in two directions, which is formed on a glass substrate via a magnesium oxide layer, is formed on a glass substrate, and a method of manufacturing the same.

It is another object of the present invention to provide a substrate for an electronic display device having a tin oxide semiconductor layer formed on a glass substrate through a magnesium oxide layer and a buffer layer and aligned in two directions on a glass substrate, and a method of manufacturing the same.

In order to achieve the above object, the present invention provides a glass substrate, a magnesium oxide (MgO) layer formed in two directions on the glass substrate, and a tin oxide semiconductor (SnO _2-x , 0 < x < 1) layer.

In the substrate for an electronic display device according to the present invention, the magnesium oxide layer may be formed on the glass substrate so as to be aligned in two directions (100) and (001). The tin oxide semiconductor layer may be formed on the magnesium oxide layer in two directions (110) and (001).

The substrate for an electronic display device according to the present invention may further include a tin oxide (SnO ₂ ) buffer layer formed between the magnesium oxide layer and the tin oxide semiconductor layer.

The substrate for an electronic display device according to the present invention may further comprise a buffer layer of Al ₂ O ₃ material formed between the magnesium oxide layer and the tin oxide semiconductor layer.

The substrate for an electronic display device according to the present invention further comprises a plurality of buffer layers such as a buffer layer of Al ₂ O ₃ material formed on the magnesium oxide layer and a tin oxide (SnO ₂ ) buffer layer formed between the buffer layer and the tin oxide semiconductor layer .

In the substrate for an electronic display device according to the present invention, the magnesium oxide layer, the tin oxide buffer layer and the tin oxide semiconductor layer may be aligned in two directions using an ion beam-assisted deposition (IBAD) method.

The present invention also provides a method of manufacturing a semiconductor device, comprising: forming a magnesium oxide (MgO) layer on a glass substrate so as to be aligned in two directions of (100) and (001) And forming a tin oxide semiconductor (SnO _2-x , 0 < x < 1) layer on the substrate.

The method of manufacturing a substrate for an electronic display device according to the present invention may further include forming a tin oxide (SnO ₂ ) buffer layer on the magnesium oxide layer, which is performed after the step of forming the magnesium oxide layer. At this time, a tin oxide semiconductor layer may be formed on the tin oxide buffer layer.

In the method of manufacturing a substrate for an electronic display according to the present invention, the step of forming the tin oxide buffer layer and the step of forming the tin oxide semiconductor layer may be successively performed.

The method for manufacturing a substrate for an electronic display device according to the present invention may further include forming a buffer layer of an Al ₂ O ₃ material on the magnesium oxide layer, which is performed after forming the magnesium oxide layer. At this time, a tin oxide semiconductor layer may be formed on the buffer layer.

A method of manufacturing a substrate for an electronic display device according to the present invention includes the steps of forming a buffer layer of an Al ₂ O ₃ material on the magnesium oxide layer, which is performed after forming the magnesium oxide layer, oxide (SnO ₂₎ may further comprise the step of forming the buffer layer. At this time, a tin oxide semiconductor layer may be formed on the tin oxide buffer layer.

According to the present invention, biaxially oriented tin oxide semiconductors based on tin oxide (SnO ₂ ) by ion beam-assisted deposition (IBAD) via a magnesium oxide (MgO) (SnO2 _-x ) layer, a tin oxide semiconductor layer having a suitable charge density and a high charge mobility and excellent in stability can be formed on a glass substrate.

In particular, when a tin oxide semiconductor layer is formed on a magnesium oxide layer, a tin oxide semiconductor layer is formed on the tin oxide buffer layer after the tin oxide buffer layer is formed on the magnesium oxide layer to a predetermined height, A tin oxide semiconductor layer having high charge mobility and excellent stability can be formed.

The present invention also provides a method of forming a tin oxide semiconductor layer after forming a buffer layer such as Al ₂ O ₃ having a crystal orientation on a magnesium oxide layer formed on a glass substrate to form a tin oxide semiconductor layer having a proper charge density and a high charge mobility A tin oxide semiconductor layer excellent in stability can be formed.

1 is a cross-sectional view showing a substrate for an electronic display device having a tin oxide semiconductor layer aligned in two directions according to a first embodiment of the present invention.
2 is a flowchart of a method of manufacturing a substrate for an electronic display device of FIG.
FIGS. 3 to 5 are views showing respective steps according to the manufacturing method of FIG.
6 is a cross-sectional view showing a substrate for an electronic display device having a tin oxide semiconductor layer aligned in two directions according to a second embodiment of the present invention.
7 is a flow chart of the method for manufacturing the substrate for an electronic display device of Fig.
FIGS. 8 to 11 are views showing respective steps according to the manufacturing method of FIG.

In the following description, only parts necessary for understanding embodiments of the present invention will be described, and descriptions of other parts will be omitted to the extent that they do not disturb the gist of the present invention.

The terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary meanings and the inventor is not limited to the meaning of the terms in order to describe his invention in the best way. It should be interpreted as meaning and concept consistent with the technical idea of the present invention. Therefore, the embodiments described in the present specification and the configurations shown in the drawings are merely preferred embodiments of the present invention, and are not intended to represent all of the technical ideas of the present invention, so that various equivalents And variations are possible.

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

First Embodiment

1 is a cross-sectional view showing a substrate for an electronic display device having a tin oxide semiconductor layer aligned in two directions according to a first embodiment of the present invention.

1, a substrate 100 for an electronic display according to the first embodiment includes a glass substrate 10, a magnesium oxide (MgO) layer, and a tin oxide semiconductor (SnO _{2 -x} , 0 <x <1) And a tin oxide (SnO ₂ ) buffer layer 40 formed between the magnesium oxide layer 20 and the tin oxide semiconductor layer 50.

The tin oxide semiconductor layer 50 is used as a semiconductor layer and the magnesium oxide layer 20 between the tin oxide semiconductor layer 50 and the glass substrate 10 and the tin oxide buffer layer 40 are used as an insulating layer.

The glass substrate 10 is an amorphous glass substrate.

The magnesium oxide layer 20 is formed on the glass substrate 10 so as to be aligned in two directions. The magnesium oxide layer 20 may be formed to a thickness of 5 to 20 nm. For example, an ion beam-assisted deposition (IBAD) method can be used as a method of forming the magnesium oxide layer 20 in two directions on the glass substrate 10. Where the two directions may be the (100) and (001) directions.

A tin oxide semiconductor layer (50) is formed on the magnesium oxide layer (20) in two directions. The tin oxide semiconductor layer 50 may be formed to a thickness of 70 to 150 nm. For example, the IBAD method may be used as a method of forming the tin oxide semiconductor layer 50 in two directions aligned on the magnesium oxide layer 20. Where the two directions may be the (110) and (001) directions.

And a tin oxide buffer layer 40 is formed between the magnesium oxide layer 20 and the tin oxide semiconductor layer 50. The tin oxide buffer layer 40 may be formed to be thicker than the thickness of the tin oxide semiconductor layer 50. That is, the tin oxide buffer layer 40 may be formed to a thickness of 70 to 1000 nm. For example, the tin oxide buffer layer 40 may be formed by the IBAD method on the magnesium oxide layer 20 so as to be aligned in two directions. Here, the two directions may be the same as the two directions of the tin oxide semiconductor layer 50.

The reason why the tin oxide buffer layer 40 is formed between the magnesium oxide layer 20 and the tin oxide semiconductor layer 50 is that the tin oxide semiconductor layer 50 having suitable charge density and high charge mobility and excellent in stability, . That is, when the tin oxide semiconductor layer 50 is directly formed on the magnesium oxide layer 20, the stability and the charge mobility may be slightly lowered. However, when the tin oxide semiconductor layer 50 is formed on the magnesium oxide layer 20 via the tin oxide buffer layer 40, the tin oxide buffer layer 40 having higher stability and higher charge mobility can be formed.

As described above, the substrate 100 for an electronic display according to the first embodiment is arranged on the glass substrate 10 in two directions based on tin oxide by the IBAD method via the magnesium oxide layer 20 aligned in two directions The tin oxide semiconductor layer 50 having a suitable charge density and a high charge mobility and having excellent stability can be formed on the glass substrate 10 by forming the tin oxide semiconductor layer 50. [ A tin oxide semiconductor layer 50 having a charge mobility of 50 or higher can be formed on the glass substrate 10, for example.

When the tin oxide semiconductor layer 50 is formed on the magnesium oxide layer 20, the tin oxide buffer layer 40 is formed on the magnesium oxide layer 20 at a predetermined height, and then the tin oxide buffer layer 40 is formed on the tin oxide buffer layer 40 By forming the tin oxide semiconductor layer 50, a tin oxide semiconductor layer 50 having a suitable charge density and a high charge mobility and excellent stability can be formed on the glass substrate 10.

A method of manufacturing the substrate 100 for an electronic display according to the first embodiment will be described with reference to FIGS. 1 to 5. FIG. Here, FIG. 2 is a flowchart according to a manufacturing method of the substrate 100 for an electronic display device of FIG. And FIGS. 3 to 5 are views showing respective steps according to the manufacturing method of FIG.

First, as shown in FIG. 3, the glass substrate 10 is prepared in step S61.

Next, as shown in FIG. 4, in step S63, the magnesium oxide layer 20 is formed on the glass substrate 10 in two directions. That is, the magnesium oxide layer 20 is formed on the glass substrate 10 by the IBAD method so as to be aligned in the (100) and (001) directions. That is, while the ion beam is scanned in the oblique direction with respect to the glass substrate 10, the magnesium oxide layer 20 can be formed by depositing particles generated from the target of the Mg material by a laser deposition method. The ion beam may be an Ar or O ₂ ion beam. The scanning angle of the ion beam may be 45 degrees with respect to the upper surface of the glass substrate 10. [

Next, as shown in FIG. 5, a tin oxide buffer layer 40 is formed in two directions on the magnesium oxide layer 20 in step S65. That is, a tin oxide buffer layer 40 is formed on the magnesium oxide layer 20 in the (110) and (001) directions by the IBAD method.

1, the tin oxide semiconductor layer 50 is formed on the tin oxide buffer layer 40 so as to be aligned in two directions in step S65, thereby forming the substrate 100 for an electronic display according to the first embodiment. Can be obtained. That is, the tin oxide semiconductor layer 50 is formed on the tin oxide buffer layer 40 in the (110) and (001) directions by the IBAD method.

At this time, steps S65 and S67 may be formed stepwise by separate processes, but the present invention is not limited thereto. For example, steps S65 and S67 can be continuously performed at one time while changing the composition ratio of tin and oxygen forming tin oxide and tin oxide semiconductor.

Second Embodiment

On the other hand, in the first embodiment, the tin oxide semiconductor layer 50 is formed on the magnesium oxide layer 20, but the present invention is not limited thereto. The buffer layer 30 may be interposed between the magnesium oxide layer 20 and the tin oxide semiconductor layer 50 to more stably form the tin oxide semiconductor layer 50 as shown in Fig.

6 is a cross-sectional view showing a substrate 200 for an electronic display device having a tin oxide semiconductor layer 50 aligned in two directions according to a second embodiment of the present invention.

6, the substrate 200 for an electronic display according to the second embodiment includes a glass substrate 10, a magnesium oxide (MgO) layer, a buffer layer 30, and a tin oxide semiconductor (SnO2 _-x , 0 & and a tin oxide (SnO ₂ ) buffer layer 40 interposed between the buffer layer 30 and the tin oxide semiconductor layer 50.

The tin oxide semiconductor layer 50 is used as a semiconductor layer and the magnesium oxide layer 20, the buffer layer 30 and the tin oxide buffer layer 40 between the tin oxide semiconductor layer 50 and the glass substrate 10 are insulated Layer.

The glass substrate 10 is an amorphous glass substrate.

The magnesium oxide layer 20 is formed on the glass substrate 10 so as to be aligned in two directions. The magnesium oxide layer 20 may be formed to a thickness of 5 to 20 nm. For example, the IBAD method may be used as a method of forming the magnesium oxide layer 20 in two directions aligned on the glass substrate 10. Where the two directions may be the (100) and (001) directions.

The buffer layer 30 is formed on the magnesium oxide layer 20 with an Al ₂ O ₃ material. The buffer layer 30 may be formed to a thickness of 5 to 20 nm. The buffer layer 30 compensates for a decrease in the physical bonding force between the magnesium oxide layer 20 and the tin oxide buffer layer 40 (or the tin oxide semiconductor layer 50) due to the difference in crystal constant between the magnesium oxide layer 20 and the tin oxide buffer layer 40 40). &Lt; / RTI &gt; In particular, by forming the buffer layer 30 from an Al ₂ O ₃ material, the tin oxide buffer layer 40 can be stably formed. As a method for forming the buffer layer 30, a physical or chemical vapor deposition method may be used.

A tin oxide buffer layer (40) is formed over the buffer layer (30). The tin oxide buffer layer 40 may be formed to be thicker than the thickness of the tin oxide semiconductor layer 50 to be formed thereon. That is, the tin oxide buffer layer 40 may be formed to a thickness of 70 to 1000 nm. For example, the tin oxide buffer layer 40 may be formed on the buffer layer 30 in the IBAD method so as to be aligned in two directions. Where the two directions may be the (110) and (001) directions.

And a tin oxide semiconductor layer 50 is formed on the tin oxide buffer layer 40 so as to be aligned in two directions. The tin oxide semiconductor layer 50 may be formed to a thickness of 70 to 150 nm. For example, the tin oxide semiconductor layer 50 may be formed on the tin oxide buffer layer 40 by the IBAD method. Where the two directions may be the same as the two directions of the tin oxide buffer layer 40.

As described above, when the tin oxide semiconductor layer 50 is formed on the magnesium oxide layer 20 and the substrate 200 for an electronic display device in the second embodiment, the tin oxide buffer layer 40 The tin oxide semiconductor layer 50 is formed on the tin oxide buffer layer 40 so that the tin oxide semiconductor layer 50 having an appropriate charge density and high charge mobility and excellent stability 50 can be formed. A tin oxide semiconductor layer 50 having a charge mobility of 50 or higher can be formed on the glass substrate 10, for example.

A tin oxide semiconductor layer 50 is formed after a buffer layer 30 such as Al ₂ O ₃ having crystal orientation is formed on the magnesium oxide layer 20 formed on the glass substrate 10, The tin oxide buffer layer 40 and the tin oxide semiconductor layer 50 can be formed stably.

A method of manufacturing the substrate 200 for an electronic display device according to the second embodiment will now be described with reference to FIGS. 6 to 11. FIG. Here, FIG. 7 is a flowchart according to a manufacturing method of the substrate 200 for an electronic display device of FIG. And FIGS. 8 to 11 are views showing respective steps according to the manufacturing method of FIG.

First, as shown in FIG. 8, the glass substrate 10 is prepared in step S61.

Next, as shown in FIG. 9, in step S63, the magnesium oxide layer 20 is formed on the glass substrate 10 in two directions. That is, the magnesium oxide layer 20 is formed on the glass substrate 10 by the IBAD method so as to be aligned in the (100) and (001) directions. The magnesium oxide layer 20 can be formed by depositing particles generated from the target of the Mg material by laser deposition while scanning the ion beam in the oblique direction with respect to the glass substrate 10, for example. The ion beam may be an Ar or O ₂ ion beam. The scanning angle of the ion beam may be 45 degrees with respect to the upper surface of the glass substrate 10. [

Next, as shown in FIG. 10, a buffer layer 30 made of Al ₂ O ₃ material is formed on the magnesium oxide layer 20 in step S64. The buffer layer 30 may be formed by physical or chemical vapor deposition.

Next, as shown in FIG. 11, a tin oxide buffer layer 40 is formed in two directions on the buffer layer 30 in step S66. That is, the tin oxide buffer layer 40 is formed on the buffer layer 30 in the (110) and (001) directions by the IBAD method.

6, the tin oxide semiconductor layer 50 is formed on the tin oxide buffer layer 40 so as to be aligned in two directions in step S68, thereby forming the substrate 200 for an electronic display according to the second embodiment. Can be obtained. That is, the tin oxide semiconductor layer 50 is formed on the tin oxide buffer layer 40 in the (110) and (001) directions by the IBAD method.

In this case, steps S66 and S68 may be formed stepwise by separate processes, but the present invention is not limited thereto. For example, steps S66 and S68 may be continuously performed at one time while changing the composition ratio of tin and oxygen forming tin oxide and tin oxide semiconductor.

It should be noted that the embodiments disclosed in the present specification and drawings are only illustrative of specific examples for the purpose of understanding, and are not intended to limit the scope of the present invention. It will be apparent to those skilled in the art that other modifications based on the technical idea of the present invention are possible in addition to the embodiments disclosed herein.

10: glass substrate
20: Magnesium oxide layer
30: buffer layer
40: tin oxide buffer layer
50: tin oxide semiconductor layer
100, 200: substrate for electronic display device

Claims (12)

A glass substrate;
A magnesium oxide (MgO) layer formed to be aligned in two directions on the glass substrate;
A tin oxide semiconductor (SnO2 _-x , 0 < x < 1) layer formed to be aligned in two directions on the magnesium oxide layer;
And a second substrate. The method according to claim 1,
The magnesium oxide layer is formed on the glass substrate so as to be aligned in two directions of (100) and (001)
Wherein the tin oxide semiconductor layer is formed on the magnesium oxide layer so as to be aligned in two directions of (110) and (001). The method according to claim 1,
A tin oxide (SnO ₂ ) buffer layer formed between the magnesium oxide layer and the tin oxide semiconductor layer;
Further comprising: a substrate; The method according to claim 1,
A buffer layer of Al ₂ O ₃ material formed between the magnesium oxide layer and the tin oxide semiconductor layer;
Further comprising: a substrate; The method according to claim 1,
A buffer layer of Al ₂ O ₃ material formed on the magnesium oxide layer;
A tin oxide (SnO ₂ ) buffer layer formed between the buffer layer and the tin oxide semiconductor layer;
Further comprising: a substrate; 6. The method according to any one of claims 1 to 5,
Wherein the magnesium oxide layer, the tin oxide buffer layer, and the tin oxide semiconductor layer are formed to be aligned in two directions using an ion beam-assisted deposition (IBAD) method. Forming a magnesium oxide (MgO) layer on the glass substrate so as to be aligned in two directions of (100) and (001);
Forming a tin oxide semiconductor (SnO _{2 -x} , 0 < x < 1) layer on the magnesium oxide layer so as to be aligned in two directions of (110) and (001);
And a step of forming a second electrode on the substrate. 8. The method of claim 7, wherein the step of forming the magnesium oxide layer further comprises:
And forming a tin oxide (SnO ₂ ) buffer layer on the magnesium oxide layer,
Wherein a tin oxide semiconductor layer is formed on the tin oxide buffer layer. 9. The method of claim 8,
Wherein the step of forming the tin oxide buffer layer and the step of forming the tin oxide semiconductor layer are continuously performed. 8. The method of claim 7, wherein the step of forming the magnesium oxide layer further comprises:
And forming a buffer layer of an Al ₂ O ₃ material on the magnesium oxide layer,
Wherein a tin oxide semiconductor layer is formed on the buffer layer. 8. The method of claim 7,
Wherein the step of forming the magnesium oxide layer comprises:
Forming a buffer layer of an Al ₂ O ₃ material on the magnesium oxide layer;
Further comprises a,, forming a tin oxide (SnO ₂₎ buffer layer on said buffer layer
Wherein a tin oxide semiconductor layer is formed on the tin oxide buffer layer. 12. The method according to any one of claims 7 to 11,
Wherein the magnesium oxide layer, the tin oxide buffer layer, and the tin oxide semiconductor layer are formed to be aligned in two directions using an ion beam-assisted deposition (IBAD) method.

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