KR101917040B1 - smart glass including vanadium dioxide film formed by low-temperature deposition and method for manufacturing thereof - Google Patents

Abstract

A smart glass and a manufacturing method thereof are disclosed. Smart glass according to an embodiment of the present invention is formed on the TiO ₂ layer and a TiO ₂ layer formed on the base substrate, the base substrate comprises depositing and annealing a vanadium dioxide thin film at a temperature not higher than 250 ℃.

Description

[0001] The present invention relates to a smart glass including a vanadium dioxide thin film formed by low temperature deposition and a method for manufacturing the same.

Embodiments of the present invention relate to a smart glass including a vanadium dioxide thin film formed by low temperature deposition and a method of manufacturing the same.

Recently, smart windows (intelligent windows) that can insulate buildings and effectively manage buildings are attracting attention due to the rapid increase of energy consumption, rising oil prices, and environmental problems caused by global warming.

In addition, considering that the energy lost in windows is 45% of the energy lost in the entire building, it is urgent to develop a new smart window technology that can minimize heat loss.

As a functional glass applicable to smart windows, vanadium dioxide (VO ₂ , vanadium dioxide) is attracting attention. Vanadium dioxide is a material having a metal-insulator transition (MIT) characteristic and a thermochromic characteristic, and optical characteristics and electrical characteristics change near the phase transition temperature.

Conventional vanadium dioxide thin films are prepared by depositing a vanadium dioxide thin film on a substrate and then heat-treating the substrate. At least 400 ° C of heat is applied to the vanadium dioxide thin film for a long time. Particularly, considering the temperature rise / down time of the chamber for reducing the reactivity with the atmosphere, the vanadium dioxide thin film is heat-treated for several hours. However, when the high-temperature deposition method is used, the crystallinity of the vanadium dioxide thin film can be improved. However, since there is a restriction on the material of the base substrate and a high processing cost, it is suitable for manufacturing a large- not.

Korean Patent Laid-Open Publication No. 2009-0090839, "Method for forming vanadium oxide film using atomic layer deposition method" Korean Patent Laid-Open Publication No. 2015-011214, "Stabilization Technology of Thermodynamically Unstable Insulator Phase in Metal-Insulator Phase Transition Material at Room Temperature by Simple Oxygen Control"

Journal of the Korean Institute of Electrical and Electronic Material Engineers. Vol. 13, No.12, pp. 1003-1010, 2000, " Effect of oxygen annealing on the structural and optical properties of vanadium oxide deposited by sputtering "

SUMMARY OF THE INVENTION An object of embodiments of the present invention is to provide a smart glass and a method of manufacturing the same that can form a vanadium dioxide thin film at a low cost without restriction of a base substrate while having a good crystallinity.

Smart glass according to the embodiment includes a TiO ₂ layer and the deposition and heat-treating the vanadium dioxide thin film at a temperature not higher than the TiO ₂ is formed on the layer 250 ℃ formed on the base substrate, said base substrate.

According to one embodiment, the vanadium dioxide thin film is deposited to 80 nm by applying a 120 W power to a vanadium target in an argon (Ar) atmosphere at 250 ° C. and 6 mTorr using a DC / RF reactive magnetron sputtering apparatus, Lt; RTI ID = 0.0 > (O2) < / RTI &_gt; atmosphere.

According to one embodiment, the smart glass may further include a SiO ₂ layer formed between the base substrate and the TiO ₂ layer.

Meanwhile, a method of manufacturing a smart glass according to an embodiment includes forming a TiO ₂ layer on a base substrate and depositing a vanadium dioxide thin film on the TiO ₂ layer at a temperature of 250 ° C or less and performing heat treatment.

According to one embodiment, the step of forming the TiO ₂ layer, IAD (Ion Assisted Deposition-beam) deposition of the TiO ₂ layer was 300㎚ using the equipment on the base substrate, to heat treatment at a temperature of 200 ℃ .

According to one embodiment, the deposition and heat treatment of the vanadium dioxide thin film on the TiO ₂ layer may be performed by applying 120 W power to the vanadium target in an argon atmosphere at 250 ° C. and 6 mTorr using a DC / RF reactive magnetron sputtering equipment Depositing the vanadium dioxide thin film at 80 nm and annealing the vanadium dioxide thin film at a temperature of 250 캜 and an oxygen (O ₂ ) atmosphere.

According to one embodiment, the method of manufacturing the smart glass may further include forming a SiO ₂ layer on the base substrate before forming the TiO ₂ layer.

According to embodiments of the present invention, by forming the vanadium dioxide thin film at a low temperature deposition method of 250 ° C or less, a smart glass can be manufactured at a low cost without restriction of the base substrate while maintaining good crystallinity for the MIT characteristics of the vanadium dioxide thin film .

1 is a view showing a smart glass according to an embodiment of the present invention.
2 is a view showing a smart glass according to another embodiment of the present invention.
3A and 3B are schematic diagrams of MIT characteristics of a smart glass according to an embodiment of the present invention.
4A to 4D are views for explaining a method of manufacturing a smart glass according to an embodiment of the present invention.
5A and 5B are graphs showing the hysteresis characteristics of the smart glass according to the embodiments.
6A and 6B are graphs illustrating changes in Raman spectra of a smart glass according to embodiments.
7A and 7B are XRD graphs of smart glasses according to embodiments.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings and accompanying drawings, but the present invention is not limited to or limited by the embodiments.

It is to be understood that when an element or layer is referred to as being " on " or " on " of another element or layer, All included. On the other hand, when a device is referred to as " directly on " or " directly above ", it does not intervene another device or layer in the middle.

The terms spatially relative, "below", "beneath", "lower", "above", "upper" May be used to readily describe a device or a relationship of components to other devices or components. Spatially relative terms should be understood to include, in addition to the orientation shown in the drawings, terms that include different orientations of the device during use or operation. For example, when inverting an element shown in the figure, an element described as " below or beneath " of another element may be placed "above" another element. Thus, the exemplary term " below " can include both downward and upward directions. The elements can also be oriented in different directions, in which case spatially relative terms can be interpreted according to orientation.

The terminology used herein is for the purpose of illustrating embodiments and is not intended to be limiting of the present invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. It is noted that the terms "comprises" and / or "comprising" used in the specification are intended to be inclusive in a manner similar to the components, steps, operations, and / Or additions.

Unless defined otherwise, all terms (including technical and scientific terms) used herein may be used in a sense commonly understood by one of ordinary skill in the art to which this invention belongs. Also, commonly used predefined terms are not ideally or excessively interpreted unless explicitly defined otherwise.

In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. The terminology used herein is a term used for appropriately expressing an embodiment of the present invention, which may vary depending on the user, the intent of the operator, or the practice of the field to which the present invention belongs. Therefore, the definitions of these terms should be based on the contents throughout this specification.

1 is a view showing a smart glass according to an embodiment of the present invention. Referring to FIG. 1, a smart glass 100 includes a base substrate 110, a TiO ₂ layer 120, and a vanadium dioxide thin film 130.

The base substrate 110 may be a glass substrate or a silicon substrate.

A TiO ₂ layer 120 is formed on the base substrate 110. Here, the TiO ₂ layer 120 has temperature stability and functions as a seed layer in forming the vanadium dioxide thin film 130.

The vanadium dioxide thin film 130 is formed on the TiO ₂ layer 120 and is deposited and heat-treated at a temperature of 250 ° C or lower. Since the vanadium dioxide thin film 130 is formed on the TiO ₂ layer 120 functioning as a seed layer, the vanadium dioxide thin film 130 has a good crystallinity even if formed by low-temperature deposition.

2 is a view showing a smart glass according to another embodiment of the present invention. Referring to FIG. 2, the smart glass 200 includes a base substrate 210, a SiO ₂ layer 220, a TiO ₂ layer 230, and a vanadium dioxide thin film 240.

The base substrate 210 may be a glass substrate or a silicon substrate.

The SiO ₂ layer 220 is formed on the base substrate 110 and functions as a diffusion barrier layer preventing ions in the base substrate 110 from diffusing into the vanadium dioxide thin film 240 through the TiO ₂ layer 230 .

A TiO ₂ layer 230 is formed on the base substrate 210. Here, the TiO ₂ layer 230 functions as a seed layer when the vanadium dioxide thin film 130 is formed.

The vanadium dioxide thin film 240 is formed on the TiO ₂ layer 230 and is deposited and heat-treated at a temperature of 250 ° C or lower. Specifically, the vanadium dioxide thin film 240 is deposited to a thickness of 80 nm by applying a 120 W power to a vanadium target at a temperature of 250 ° C. and an argon (Ar) atmosphere of 6 mTorr using a DC / RF reactive magnetron sputtering apparatus. Of oxygen (O ₂ ) atmosphere.

At present, it is preferable to use a compound such as VO ₂ , V ₂ O ₃ , V ₃ O ₅ , V ₄ O ₇ , V ₆ O ₁₁ , V ₅ O ₉ , V ₆ O ₁₃ , V ₄ O ₉ , V ₃ O ₇ , V ₂ O ₅ Various vanadium oxides are present, but the metal-insulator transition (MIT) and thermochromic properties are only present in vanadium dioxide (VO ₂ ). That is, the vanadium dioxide (VO ₂ ) optically transmits the IR region and becomes electrically nonconductive at a phase transition temperature or lower, and when the temperature is above the phase transition temperature, the IR region is optically cut off and becomes electrically conductive. This phase transition phenomenon is known to be caused by the change of the VOV bond of vanadium dioxide from a covalent bond to a metal bond.

In order to manufacture the large-sized smart glass 200 having improved MIT characteristics and thermochromic characteristics as described above, the vanadium dioxide thin film 240 should have good crystallinity, and the base substrate 210 should be free of any restriction.

Although the vanadium dioxide thin film 240 is formed on the TiO ₂ layer 230 serving as the seed layer and the SiO ₂ layer 220 serving as the diffusion preventing layer in spite of being formed by the low temperature deposition in the present embodiment, I have sex.

Further, since the vanadium dioxide thin film 240 is formed at a temperature lower than 250 캜, the substance of the base substrate 210 which can withstand this temperature expands. Accordingly, the selection range of the base substrate 210 is widened, a relatively inexpensive material can be used as the base substrate 210, and a large-sized smart glass 200 can be manufactured at low cost.

3A and 3B are schematic diagrams of MIT characteristics of a smart glass according to an embodiment of the present invention.

Referring to FIG. 3A, when sunlight is irradiated in an environment above the phase transition temperature as in the summer, the smart glass 200 transmits visible light in the sunlight and reflects light in the IR area and some other light. Accordingly, the smart glass 200 can prevent the inflow of solar heat into the room by reflecting infrared rays in a high temperature environment such as summer.

Referring to FIG. 3B, when sunlight is irradiated in an environment below the phase transition temperature as in the winter, the smart glass 200 transmits light in the visible light region and the IR region of sunlight and reflects some light. Accordingly, the smart glass 200 can transmit the infrared ray in a low temperature environment such as winter, thereby increasing the indoor temperature, and preventing radiant heat in the room from flowing out to the outside.

By manufacturing the smart glass 200 as described above in a large area and applying it to a smart window, it is possible to reduce the cooling and heating energy of the room.

3A and 3B show the MIT characteristics for the smart glass 200, the smart glass 100 shown in FIG. 1 also exhibits the same or similar MIT characteristics.

4A to 4D are views for explaining a method of manufacturing a smart glass according to an embodiment of the present invention. Referring to FIG. 4A, the manufacturing method includes forming an SiO ₂ layer 412 on a base substrate 411. Here, the base substrate 411 may be a glass substrate, a silicon substrate, or the like. However, the present invention is not limited to this, and other substrate types can be used as the base substrate 411 as long as they are transparent substrates that can transmit light.

The SiO ₂ layer 412 may serve as a diffusion barrier to prevent diffusion of ions in the base substrate 410 into the TiO ₂ layer and the vanadium dioxide film formed in a subsequent process. 4A, the process of forming the SiO ₂ layer 412 on the base substrate 411 has been illustrated and described. In the present invention, however, this process can be selectively applied. A TiO ₂ layer is formed on the base substrate 411 It can also be formed immediately.

As in FIG. 4B, the manufacturing method includes forming a TiO ₂ layer 413 on the SiO ₂ layer 412. Specifically, after the base substrate 411 on which the SiO ₂ layer 412 is formed is mounted in an ION (Ion beam Assisted Deposition) chamber, the TiO ₂ layer 413 is vacuum deposited, and the TiO ₂ layer Ions are irradiated onto the TiO ₂ layer 413 to form a TiO ₂ layer 413 in a dense film form. Then, the TiO ₂ layer 413 having a thickness of 300 nm can be formed by performing heat treatment at 200 ° C for 15 minutes. The thus prepared TiO ₂ layer 413 functions as a seed layer for a vanadium dioxide thin film to be formed in a subsequent process, thereby improving the crystallinity of the vanadium dioxide thin film.

Then, as shown in FIG. 4C, the manufacturing method includes a step of depositing a vanadium dioxide thin film 420 on the TiO ₂ layer 413 at a low temperature of 250 ° C. or less by using a DC / RF reactive magnetron sputter 10, . Specifically, the structure 410 in which the base substrate 411, the SiO ₂ layer 412 and the TiO ₂ layer 413 are sequentially formed is mounted on the holder 12 in the vacuum chamber 11, and the vanadium target 14 And is mounted on the sputter gun 13. Here, the structure 410 is dropped from the vanadium target 14 by about 15 cm. Vacuum in the vacuum chamber 11 is drawn to 3 x 10 ^-6 torr by using a vacuum pump 17 and then a DC or RF power is supplied to the structure 410 while maintaining the structure at a temperature of 250 ° C. Power supply (18).

At this time, the argon gas supplied through the argon gas container 16a was controlled to a partial pressure of 10 sccm by using an MFC (Mass Flow Controller) 15, the pressure in the vacuum chamber 11 was maintained at 6 mTorr, Is supplied to the vanadium target 14 to generate plasma. In this manner, the vanadium dioxide thin film 420 can be deposited to a thickness of 80 nm for 2 hours.

Then, the oxygen gas supplied through the oxygen gas container 16c is adjusted to a partial pressure of 1 sccm, and the vanadium dioxide thin film 420 is heat-treated at 250 ° C for about 1 hour. Thus, the deposition of the vanadium dioxide thin film 420 and the heat treatment process are performed at a low temperature of 250 ° C or lower, so that there is no restriction on the material of the base substrate 411 and the process cost can be reduced, . ≪ / RTI >

Even if the vanadium dioxide thin film 420 is formed at a low temperature, it is formed on the SiO ₂ layer 412 serving as the diffusion preventing layer and the TiO ₂ layer 413 serving as the seed layer, It is possible to improve the property.

5 to 7 are graphs based on experimental data measuring optical characteristics of a smart glass according to embodiments of the present invention. Here, the smart glass according to the first and second embodiments is as follows.

≪ Example 1 >

("Si-TiO ₂ -VO ₂ ") having a structure in which a TiO ₂ layer and a vanadium dioxide thin film are sequentially formed on a silicon substrate, as shown in FIG. Here, the TiO ₂ layer can function as a seed layer of a vanadium dioxide thin film.

≪ Example 2 >

("Si-SiO ₂ -TiO ₂ -VO ₂ ") having a structure in which a SiO ₂ layer, a TiO ₂ layer and a vanadium dioxide thin film are formed in order on a silicon substrate, as shown in FIG. In the manufacturing process of the smart glass according to Example 2, the SiO ₂ layer functions as a diffusion preventing layer and the TiO ₂ layer can function as a seed layer of a vanadium dioxide thin film.

5A and 5B are graphs showing the hysteresis characteristics of the smart glass according to the embodiments. In FIGS. 5A and 5B, the ambient temperature of the smart glass according to the first and second embodiments is heated and cooled, The resistance change was measured.

Referring to FIG. 5A, the hysteresis characteristic of the smart glass according to Example 1 is observed at 42.63 DEG C (Tc) upon heating and cooling. It can be seen that the vanadium dioxide thin film (VO ₂ ) contained in the smart glass of Example 1 exhibits a phase transition characteristic in which the crystal structure changes from monoclinic to orthorhombic at 42.63 ° C.

Referring to FIG. 5B, the hysteresis characteristic is observed at 44.19 DEG C in the heating and cooling of the smart glass according to the second embodiment. It can be seen that the vanadium dioxide thin film (VO ₂ ) contained in the smart glass of Example 2 exhibits a phase transition characteristic in which the crystal structure changes from monoclinic to orthorhombic at 44.19 ° C (Tc).

5A and 5B, in the smart glass according to Examples 1 and 2, the phase transition temperature was reduced to about room temperature, and the width of the hysteresis curve was narrow.

In particular, the smart glass according to the first embodiment has a lower phase transition temperature and narrower hysteresis curve than the second embodiment. This can be interpreted as the TiO ₂ layer formed on the silicon substrate has better crystallinity than the TiO ₂ layer formed on the SiO ₂ layer having an amorphous structure, and this crystallinity affects the vanadium dioxide thin film .

6A and 6B are graphs illustrating changes in Raman spectra of a smart glass according to embodiments.

Also in the Raman spectrum of smart glass according to Example 1 Referring to 6a, vanadium dioxide thin film (VO ₂₎ peak was observed in the vicinity of 620㎝ 220㎝ ^{-1 -1} vicinity of a peak of TiO ₂ layer 200 Cm < ^-1 > and around 520 cm <" ¹ >.

Also, Referring to Figure 6b, the second embodiment in the Raman spectrum of smart glass according to the peak of a vanadium dioxide thin film (VO ₂₎ was observed in the vicinity of 620㎝ 220㎝ ^{-1 -1} vicinity, the peak of TiO ₂ layer 180㎝ ^-1 vicinity, 390㎝ ^-1 vicinity 520㎝ ^-1 was observed in the vicinity.

Referring to Figure 6a and Figure 6b, Examples 1 and vanadium dioxide thin film on the glass according to the Smart ₂ (VO 2) is to represent a unique peak in the vicinity of 620㎝ 220㎝ ^{-1 -1} vicinity of the seed layer to TiO ₂ layer It can be seen that it has good crystallinity.

In the smart glass according to Example 1, the TiO ₂ layer is formed on the silicon substrate having a single crystal structure, and thus the intrinsic peak of the TiO ₂ layer is well represented.

Further, in the smart glass according to Example 2, the TiO ₂ layer also shows the intrinsic peak of the TiO ₂ layer. However, it can be understood that a peak is generated in the vicinity of 390 cm ^{-1 as the} TiO ₂ layer is formed on the amorphous SiO ₂ layer.

FIGS. 7A and 7B are XRD graphs obtained by measuring X-ray rotation analysis at a θ angle of 20 ° to 80 ° on a smart glass according to the embodiments. The XRD graph shows the degree of crystallization of the vanadium dioxide thin film (VO ₂ ) .

As in FIG. 7A, the peak intensity of the vanadium dioxide thin film (VO ₂ ) in the smart glass according to Example 1 was observed when 2? = About 28 ° and 2? = About 56 °.

7B, the peak intensity of vanadium dioxide (VO ₂ ) in the smart glass according to Example 2 was observed when 2θ = about 28 °, 2θ = about 56 °, 2θ = about 58 °.

Referring to FIGS. 7A and 7B, in the smart glass according to Example 1, the TiO ₂ layer has a good crystallinity since peaks are generated at positions corresponding to the TiO ₂ layer.

Example 2 of the smart glass, TiO ₂ layer has a peak in a different position and the peak of the TiO ₂ layer shown in Figure 7a there is generated according to which the part that is not crystallized in accordance with the formed on the SiO ₂ layer having an amorphous structure, .

On the other hand, in the smart glass according to Examples 1 and 2, the vanadium dioxide thin film (VO ₂ ) has a good crystallinity because peaks are generated at about 28 ° and about 56 ° corresponding to a monoclinic system. Referring to this, even when the TiO ₂ layer is formed on the SiO ₂ layer, the crystallinity of the vanadium dioxide thin film (VO ₂ ) is not greatly affected.

While the invention has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. This is possible.

Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined by the equivalents of the claims, as well as the claims.

100, 200: Smart glass
110, 210: Base substrate
220: SiO ₂ layer
120, 230: TiO ₂ layer
130, 240: vanadium dioxide thin film

Claims (5)

A base substrate;
A diffusion barrier layer made of SiO ₂ formed on the base substrate;
A seed layer made of TiO ₂ formed on the diffusion preventing layer; And
A vanadium dioxide thin film formed by depositing and heat-treating the seed layer at a temperature of 250 ° C or lower
/ RTI >
Wherein the vanadium dioxide thin film has a crystal structure changed from monoclinic to orthorhombic at a phase transition temperature of 44.19 ° C.
delete The method according to claim 1,
In the vanadium dioxide thin film,
DC / RF using reactive magnetron sputtering equipment is a 120W power for vanadium target in 250 ℃ temperature and argon (Ar) atmosphere at 6mTorr to be deposited at a 80㎚, the heat-treated in an oxygen (O ₂₎ atmosphere at less than 250 ℃, Smart glass. delete delete

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