KR20150113392A - Method of manufacturing metal oxide thin-layer having spinel structure - Google Patents

Abstract

In a method to manufacture a metal oxide thin-layer having a spinel structure, a metal oxide thin-layer is formed by mixing a precursor solution including nickel oxide and manganese oxide with an organic solvent to manufacture a mixed solution; coating a substrate with the mixed solution to form a coating layer; baking the coating layer to form a seed layer; and crystallizing the seed layer at a temperature greater than 400°C and equal to or lower than 800°C.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a metal oxide thin film having a spinel structure,

The present invention relates to a method for producing a metal oxide thin film having a spinel structure, and more particularly, to a method for producing a metal oxide thin film having a spinel structure used as a negative temperature coefficient thermistor (NTC thermistor) .

In general, a thermistor, which is a kind of temperature sensor, is composed of a negative temperature coefficient (NTC) thermistor using a phenomenon in which the resistance decreases as the temperature increases and a resistance And a positive temperature coefficient (PTC) thermistor.

In particular, NTC thermistors are widely used in a variety of technical fields because they have a semiconductor property whose resistance exponentially decreases over a wide temperature range. The NTC thermistor is based on a transition metal oxide having a spinel structure, and the materials used for the NTC thermistor include NiO, MnO ₄ , and Co ₃ O ₄ .

The NTC thermistor is manufactured in the form of a thin film and is used for forming the thin film by electron-beam evaporation, room temperature vacuum powder deposition, pulsed laser deposition, RF sputtering RF sputtering) are mainly used.

However, in order to manufacture a thin film type NTC thermistor by the above-described methods, high-vacuum equipment is required, and it is disadvantageous in that it is not suitable for commercial production because it involves a high-temperature process of about 1000 ° C or more or a deposition rate is very low.

It is an object of the present invention to provide a method for manufacturing a metal oxide thin film having a spinel structure, which easily manufactures a thin film NTC thermistor in a non-vacuum condition.

In one aspect, the present invention provides a method for producing a metal oxide thin film having a spinel structure. In the above manufacturing method, a precursor solution containing nickel oxide and manganese oxide is mixed with an organic solvent to prepare a mixed solution, the mixed solution is coated on a substrate to form a coating layer, and the coating layer is baked to form a seed layer Thereafter, the seed layer is crystallized at a temperature higher than 400 DEG C and 800 DEG C or lower to form a metal oxide thin film.

In one embodiment, crystallization of the seed layer may be performed at 410 ° C to 510 ° C.

In one embodiment, in forming the seed layer, the temperature may be raised at a rate of 7 [deg.] C / min to 13 [deg.] C / min.

In one embodiment, the rate of temperature rise in the step of forming the seed layer may be 10 ° C / min.

In one embodiment, the step of forming the seed layer may be heated to 380 to 420 占 폚.

In one embodiment, in the precursor solution, the atomic ratio of nickel to oxygen in the nickel oxide is 1: 1, the atomic ratio of oxygen to manganese in the manganese oxide is 1: 1.5, and the metal oxide thin film is nickel- NiMn ₂ O ₄ ).

In one embodiment, before forming the metal oxide thin film, a step of forming a coating layer on the seed layer using the mixed solution, and baking the coating layer on the seed layer may be further performed.

In one embodiment, the metal oxide thin film may be composed of nickel-manganese oxide (NiMn ₂ O ₄ ).

In one embodiment, the precursor solution further comprises copper oxide (CuO), wherein the metal oxide thin film may comprise nickel-manganese-copper oxide.

In one embodiment, the metal oxide thin film may comprise nickel-manganese-copper oxide ((1-x) NiMn ₂ O ₄ - (x) CuO, where 0.2 x 0.4).

According to the present invention, a metal oxide thin film containing a nickel-manganese oxide having a spinel structure can be produced through a simple process in a non-vacuum condition, thereby lowering the manufacturing cost and making it commercially available.

1 is a flow chart for explaining a method of manufacturing a metal oxide thin film having a spinel structure according to the present invention.
2 is an XRD graph of a thin film according to the temperature of the crystallization process.
FIG. 3 is an FS-SEM photograph of the metal oxide thin film prepared according to Example 1 of the present invention, and FIG. 4 is a TEM photograph of the inside of the metal oxide thin film produced according to Example 1 of the present invention.
5 is a TEM photograph and a SAED photograph of the surface of a metal oxide thin film produced according to Example 1 of the present invention.
Fig. 6 is FE-SEM photographs of thin films according to the temperature of the crystallization process.
7 is a process diagram for illustrating a process of forming a sample element using a metal oxide thin film.
8 is a graph showing the resistivity of nickel-manganese-copper oxide with respect to the content of copper oxide.
FIG. 9 is a graph showing the resistance of nickel-manganese-copper oxide according to the content of copper oxide with temperature change.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and similarities. It is to be understood, however, that the invention is not intended to be limited to the particular forms disclosed, but on the contrary, is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the term "comprises" or "having" is intended to designate the presence of stated features, elements, etc., and not one or more other features, It does not mean that there is none.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

1 is a flow chart for explaining a method of manufacturing a metal oxide thin film having a spinel structure according to the present invention.

Referring to FIG. 1, a precursor solution is prepared for preparing a metal oxide thin film having a spinel structure according to the present invention (Step S100), and a mixed solution is prepared by mixing the precursor solution and an organic solvent (Step S200).

The precursor solution includes a precursor of the metal oxide constituting the metal oxide thin film. The precursor of the metal oxide may be a compound containing a metal constituting the metal oxide.

The metal oxide thin film includes a nickel-manganese oxide (NiMn ₂ O ₄ ) having a spinel structure. At this time, the precursor may include nickel oxide and manganese oxide. At this time, the atomic ratio of nickel and oxygen of nickel oxide is 1: 1, and the atomic ratio of oxygen and manganese oxide is 1: 1.5. Depending on the structure and atomic ratio of the metal oxide, the atomic ratio of the precursor can be controlled.

Alternatively, if the metal oxide thin film further comprises a doped metal oxide in addition to the nickel-manganese oxide, a metal oxide for doping with the precursor may be added to the precursor solution. For example, the metal oxide thin film may be doped with copper oxide, cobalt oxide, or the like. At this time, the precursor solution may further include copper oxide or cobalt oxide together with nickel oxide and manganese oxide. The metal oxide thin film may be doped with a metal oxide such as copper oxide or cobalt oxide to lower the crystallization temperature of the nickel-manganese oxide.

The organic solvent forms a metal organic compound with the precursors. Examples of the organic solvent include methanol, acetic acid, ethylene glycol, and butylacetate. For example, by using butyl acetate as an organic solvent, a high-purity precursor solution can be prepared.

The mixed solution may be prepared by mixing and stirring the precursor solution and the organic solvent. The mixed solution may include a metal organic compound in which a precursor and an organic solvent are combined.

Next, a coating layer is formed on the silicon substrate with the mixed solution (step S300).

The coating layer may be formed by spin coating, dip coating, spray coating, roll coating, slot-die coating, ink-jet printing (ink coating) -jet printing) or the like. For example, the coating solution may be thinly and uniformly formed by dripping the mixed solution onto the silicon substrate as a whole, and rotating the spin coater thereon.

The thickness of the coating layer can be controlled according to the method of forming the coating layer and the properties of the mixed solution, for example, molarity or viscosity.

Meanwhile, the coating layer may be formed on a silicon substrate having a silicon nitride film formed thereon. That is, the coating layer may be formed on the silicon nitride film. Before forming the coating layer, the silicon substrate having the silicon nitride film formed thereon may be cleaned with acetone, ethanol, and / or distilled water.

The coating layer is baked to form a seed layer (step S400).

The baking process of the coating layer may be performed at a temperature of 380 ° C to 420 ° C. However, after the coating layer is formed at room temperature, the temperature is increased from room temperature to 7 ° C / min to 13 ° C / min to reach the temperature range. The metal organic compound is pyrolysed through the baking process to form a seed layer containing an amorphous metal oxide.

If the temperature of the baking step is lower than 380 ° C, the metal organic compound may not be thermally decomposed or may only partially occur, resulting in insufficient formation of a seed for crystallization. If the temperature of the baking step is higher than 420 ° C, excessive stress and microcracks may occur in the baking step, which may adversely affect the formation of the seed layer.

At the same time, if the temperature raising rate is slower than 7 캜 / minute, the time required for raising the temperature becomes excessively long and the whole process time becomes long. If the temperature raising rate is faster than 13 캜 / minute, a part of the metal organic compounds evaporate instantaneously The crystallization is lowered in the subsequent crystallization process and many pores are generated on the surface or inside of the thin film due to stress and microcracks, resulting in a problem of cracking of the thin film surface. Therefore, a thin film having a smooth surface as a whole can be formed on the silicon substrate by controlling the rate of temperature increase for baking the coating layer from room temperature to 7 ° C / min to 13 ° C / min. Preferably, when the temperature of the baking step is set to 400 占 폚, both the processing time and the surface of the seed layer can be stably controlled when the temperature raising rate is 10 占 폚 / min.

On the other hand, after forming the seed layer as described above, the coating layer may be formed on the seed layer using the mixed solution. A seed layer directly formed on the silicon nitride film is referred to as a "primary seed layer ", a coating layer is formed on the primary seed layer using the mixed solution, and the coating layer is baked to form a secondary seed layer . In addition, a tertiary seed layer can be formed on the secondary seed layer, and a coating layer can be formed in consideration of the final thickness of the metal oxide thin film to be manufactured and baked.

It is difficult to form a coating layer having uniform thickness over the entire surface of the silicon substrate when the coating layer is thick at a time, for example, about 100 nm or more. In the baking process, the metal organic compound in the coating layer , There is a problem that it is difficult to decompose. Accordingly, it is preferable that the thickness of the coating layer formed at one time is set to about 50 nm or less, and the step of baking the same is repeated a plurality of times to control the thickness of the coating layer.

The seed layer is annealed to perform a crystallization process (step S500).

The seed layer may be converted into the metal oxide thin film by decomposing the decomposed metal organic compounds, i.e., the seed, crystallizing to form the metal oxide constituting the seed layer. The crystallization process is performed at a temperature of more than 400 ° C but not more than 800 ° C.

When the temperature of the crystallization process is 400 ° C or lower, crystallization does not occur, and only the amorphous thin film having substantially the characteristics of the seed layer is present, or only a small number of microcrystals having a diameter of about 3 nm or less are partially And the characteristics of the metal oxide thin film are hardly displayed. Further, when the temperature of the crystallization process is higher than 800 ° C., the time required for reaching the process temperature becomes longer, which increases the overall process time and lowers the economical efficiency such as the provision of high-temperature equipment. Therefore, the temperature of the crystallization process is performed in a temperature range of 400 ° C to 800 ° C, preferably 410 ° C to 650 ° C. More preferably, the temperature of the crystallization process may be from 410 ° C to 510 ° C. As described above, the crystallization process is performed at a temperature of about 500 ° C., so that it can be easily used in a manufacturing process on a ROIC (read-out integrated circuit) substrate.

According to the above description, a metal oxide thin film containing a nickel-manganese oxide having a spinel structure is manufactured through a simple process under a low-temperature non-vacuum condition at about 500 ° C. Which can lower the manufacturing cost and be commercially available.

Hereinafter, a method for producing a metal oxide thin film according to the present invention will be described in more detail through examples and comparative examples, samples thus prepared, and comparative samples.

Example 1: NiMn ₂ O ₄ Manufacturing

Butyl acetate (butylacetate) was added to a precursor solution containing NiO and MnO _1.5 at a concentration of 0.2 mol / L using an EMOD solution (trade name: Kojundo, Japan) as a starting material at a concentration of 0.5 mol / Was prepared. After the mixed solution was stirred for about 1 hour, the mixed solution was coated on a silicon substrate having a silicon nitride film formed thereon by a spin coater to form a coating layer. Before forming the coating layer, the silicon substrate on which the silicon nitride film was formed was ultrasonically washed with acetone, ethanol and distilled water for 10 minutes each.

The coating layer was formed by coating 0.5 mL of the mixed solution on a cleaned silicon substrate and rotating the spin coater at 1000 rpm for about 30 seconds. Subsequently, the silicon substrate on which the coating layer was formed was placed on a hot-plate, heated to 400 ° C at a heating rate of 10 ° C / min, and baked to form a first seed layer. A coating layer is formed on the first seed layer and a baking process is performed to form a second seed layer, and then a third seed layer is formed on the second seed layer.

The first, second and third seed layers were subjected to a heat treatment process in a tube furnace at 500 ° C for about 1 hour to prepare a metal oxide thin film (sample 1) according to Example 1 of the present invention Respectively.

Examples 2, 3 and 4

The metal oxide thin films according to Examples 2, 3 and 4 (samples (samples) according to Examples 1, 2 and 3 were prepared in the same manner as the method for producing the metal oxide thin film according to Example 1 except that the temperature of the heat treatment process was set to 600 캜, 700 캜, 2, 3 and 4).

Comparative Example 1

A mixed solution substantially the same as that described in Example 1 was prepared, 0.5 mL was applied on a cleaned silicon substrate, and the spin coater was rotated at 1000 rpm for about 30 seconds to prepare a thin film according to Comparative Example 1 (Comparative Sample 1) .

Comparative Example 2

A thin film according to Comparative Example 2 (Comparative Sample 2) was produced in the same manner as in the method of producing the metal oxide thin film according to Example 1, except that the temperature of the heat treatment step was set at 400 캜.

Crystallinity analysis of thin films

XRD (X-ray diffraction) analysis was performed to confirm the crystallinity of the thin films prepared according to Examples 1 to 4 and Comparative Examples 1 and 2, and the results are shown in Fig. XRD analysis was performed using D / Max-2500V / PC (trade name, Rigaku, Japan).

Further, the metal oxide thin film produced according to Example 1 was photographed by SEM (Scanning Electron Microscope) and FE-TEM (Field Emission Transmission Electron Microscope). The FE-TEM was equipped with JEM-4010 (trade name, Jeol, Japan). The results are shown in Fig. 3 and Fig.

In addition, SAED (Selected Area Electron Diffraction) analysis was performed on the metal oxide thin film produced according to Example 1. The results are shown in Fig.

2 is an XRD graph of a thin film prepared according to Examples and Comparative Examples.

Referring to the intensity (unit au) according to the diffraction angle (2?) Of the metal oxide thin film according to Example 1 crystallized at 500 ° C. shown in FIG. 2, a diffraction peak appears at about 35 ° and about 37 ° Able to know. It can be seen that the spinel structure grown in the (311) direction through the diffraction peak at about 35 ° is formed to have the spinel structure of the metal oxide thin film grown in the (222) direction through the diffraction peak shown at about 37 °.

FIG. 3 is an FS-SEM photograph of the nickel-manganese oxide prepared according to Example 1 of the present invention, and FIG. 4 is a TEM photograph of the inside of the metal oxide thin film produced according to Example 1 of the present invention. The inside of the metal oxide thin film in Fig. 4 means a metal oxide thin film in a portion in contact with the silicon nitride film.

3, it can be seen that the metal oxide thin film heat-treated at 500 ° C is formed to a thickness of about 110 nm on the silicon nitride film on the silicon substrate. It can be seen that the metal oxide thin film is uniformly formed over the entire surface, and the metal oxide thin film is deposited at a high density without pores therein. 4, large grains having a diameter of about 20 nm or more are formed in the metal oxide thin film manufactured according to the first embodiment of the present invention.

5 is a TEM photograph and a SAED photograph of the surface of a metal oxide thin film produced according to Example 1 of the present invention. It can be seen from the SAED picture of FIG. 5 that the nickel-manganese oxide constituting the metal oxide thin film is polycrystalline and grown in the (311) direction and the (400) direction. It can be seen from the TEM photographs shown in FIG. 5 that microcrystalline grains having a diameter of about 2 nm to 3 nm are formed. 4, since the seeds formed in the seed layer through the baking process grow in the heat treatment process, they can be seen to be formed in the metal oxide thin film with a relatively larger size than the microcrystalline grains found in FIG. 5 .

In this connection, the intensity of the diffraction peak of the metal oxide thin film produced according to Example 1 in the XRD graph of FIG. 2 is lowered by a large number of microcrystal grains having a diameter of 2 nm to 3 nm, As shown in FIG.

Referring again to FIG. 2, in the graph of the metal oxide thin film according to Example 2 crystallized at 600 ° C, a diffraction peak appears at an additional angle of about 43 °, indicating that the spinel structure grown in the (400) It can be confirmed that the metal oxide thin film is formed. It can also be seen that the strength of the diffraction peak at about 35 DEG has a larger value than that of the metal oxide thin film prepared according to Example 2, compared with the metal oxide thin film prepared according to Example 1. [ As a result, it can be seen that, when the temperature of the crystallization process is 600 ° C., more crystal grains are generated and the crystal grain size is larger than that at 500 ° C.

In each of the metal oxide thin films according to Example 4 crystallized at 700 ° C and crystallized at 800 ° C according to Example 4, diffraction peaks appear at about 29.5 ° as well as at diffraction peaks at about 35 °, about 37 °, and about 43 ° Able to know. As a result, it can be seen that a metal oxide thin film having a spinel structure grown in the (220) direction is formed, and it is found that as the crystallization temperature is increased from 600 ° C to 700 ° C and 800 ° C, more crystal grains are formed and the crystal grain size becomes larger have. However, when the temperature of the crystallization process is 800 ° C, the tendency of the XRD graph when the temperature of the crystallization process is 700 ° C is substantially the same.

As described above, according to the results of the analysis of the metal oxide thin films prepared according to Examples 1 to 4, it was confirmed that the diffraction peak at 29.5 °, 35 °, 37 ° and 43 °, It can be seen that no diffraction peaks other than the peak are observed. From this, it can be seen that a single phase of nickel-manganese oxide has grown on the silicon substrate. The reason why the intensity of the diffraction peak due to the nickel-manganese oxide is lower than the intensity of the diffraction peak of the silicon substrate is that the thickness of the silicon substrate is smaller than the thickness of the metal oxide thin film and the grain size is small.

On the other hand, in the XRD graph of the thin film according to Comparative Examples 1 and 2, it can be seen that the diffraction peaks other than the diffraction peak due to the silicon substrate are not shown. That is, it can be seen that the coating layer coated with the mixed solution does not contain the crystallized metal oxide and exists as an amorphous thin film in which crystallization does not occur even when the seed layer is heat-treated at 400 ° C.

Although not shown in the drawings, the annealing temperature of the seed layer was varied from 410 ° C. to 490 ° C. at intervals of 10 ° C. As a result, it was found that the temperature at which crystallization started to occur in the seed layer was about 410 ° C.

Fig. 6 is FE-SEM photographs of thin films according to the temperature of the crystallization process.

6 (a) is a photograph of the surface of the thin film prepared according to Comparative Example 1, (b) is a thin film prepared according to Comparative Example 2, (c) is a metal oxide thin film prepared according to Example 1, d) is a photograph of the surface of the metal oxide thin film prepared according to Example 4. Fig.

Referring to FIG. 6 (a), it can be seen that the surface of the coating layer coated with the mixed solution on the silicon substrate looks like a net. The white line in the photograph indicates that the mixed solution is a relatively large portion of the solution as compared with the other portions. Referring to FIG. 6 (b), it can be confirmed that the white line is almost eliminated by performing the baking process and the heat treatment process at 400 ° C. Further, it can be seen that the area divided by the white line is wider as compared with (a). Particularly, the baking process is carried out at a temperature raising rate of 10 ° C / min while gradually raising to 400 ° C, which shows that the thin film surface is smooth.

In contrast, in FIG. 6C, it can be confirmed that the area wider than the area partitioned by the white line in FIG. 6B, that is, the white line is almost eliminated, and in FIG. That is, it can be seen that many crystal grains are produced by performing the heat treatment process at 500 ° C and 800 ° C.

Example 5: (0.8) NiMn ₂ O ₄ - (0.2) CuO production

The silicon substrate on which the silicon nitride film was formed was ultrasonically washed with acetone, ethanol and distilled water for 10 minutes to prepare a cleaned silicon substrate. (0.2) prepared by adding butylacetate (butylacetate) to a precursor solution containing NiO, MnO _1.5 and CuO by using an EMOD solution (trade name: Kojundo, Japan) as a starting material at a concentration of 0.5 mol / mol / L was used to form a coating layer on the silicon substrate.

The coating layer was formed by coating 0.5 mL of the mixed solution on a cleaned silicon substrate and rotating the spin coater at 1000 rpm for about 30 seconds. Subsequently, the silicon substrate on which the coating layer was formed was placed on a hot-plate, heated to 400 ° C at a heating rate of 10 ° C / min, and baked to form a first seed layer. A coating layer is formed on the first seed layer and a baking process is performed to form a second seed layer, and then a third seed layer is formed on the second seed layer.

The first, second and third seed layers were subjected to a heat treatment process in a tube furnace at 500 ° C for about 12 hours to prepare a metal oxide thin film (Sample 5) according to Example 5 of the present invention Respectively.

Examples 6 to 9

A metal oxide thin film was prepared according to Examples 6, 7, 8 and 9 through substantially the same process as that of Example 5 except for the content of CuO. Each of the metal oxide thin films (Samples 6, 7, 9 and 9) prepared according to Examples 6 to 9 was produced in the following composition.

The metal oxide thin film prepared according to Example 6: (0.75) NiMn ₂ O ₄ - (0.25) CuO

The metal oxide thin film prepared according to Example 7: (0.7) NiMn ₂ O ₄ - (0.3) CuO

The metal oxide thin films prepared according to Example 8 were: (0.65) NiMn ₂ O ₄ - (0.35) CuO

The metal oxide thin film prepared according to Example 9: (0.6) NiMn ₂ O ₄ - (0.4) CuO

Fabrication of sample devices

7 is a process diagram for illustrating a process of forming a sample element using a metal oxide thin film. 7A, a sample 5 including a metal oxide thin film (MOL) prepared according to Example 5 was prepared on a silicon substrate SU, and then patterned and ion milled as shown in FIG. 7B . Then, an electrode pad EP connected to the metal oxide thin film pattern (MOP) was formed as shown in FIG. 7 (c).

Sample devices 2, 3, 4 and 5 were fabricated using the metal oxide thin films of samples 6, 7, 8 and 9, respectively, through substantially the same process as that of sample device 1.

Further, a sample element 6 was prepared using the metal oxide thin film of Sample 1 through a process substantially the same as that of the sample element 1.

Characterization of Thin Films: Resistivity and TCR

The resistivity at room temperature of about 25 ° C to 30 ° C was measured using each of the sample devices 1 to 6 prepared above, and the change in resistivity was measured according to the temperature change. In addition, TCR (Temperature Coefficient of Resistance) was calculated. The results are shown in Figs. 8 and 9 and Table 1 below.

division Measuring temperature Resistivity
(Unit: Ω · cm) TCR
(Unit:% / K) Sample Device 1 RT 13.86 -1.41 80 ~ 85 ℃ 4.51 -1.65 Sample device 2 RT 12.01 -3.07 80 ~ 85 ℃ 0.99 -3.05 Sample device 3 RT 8.92 -4.57 80 ~ 85 ℃ 0.9 -1.09 Sample device 4 RT 8.01 -2.83 80 ~ 85 ℃ 1.76 -3.01 Sample device 5 RT 6.81 -2.37 80 ~ 85 ℃ 1.83 -2.32

8 is a graph showing the resistivity of nickel-manganese-copper oxide with respect to the content of copper oxide. Referring to Table 1 and FIG. 8, the resistivity at room temperature of the metal oxide thin film (sample element 6) prepared according to Example 1 of the present invention is about 1033.5? 占 ㎝ m, The resistivities of the metal oxide thin films (sample elements 1 to 5) of the present invention are about 13.86? Cm, 12.01? Cm, 8.92? Cm, 8.01? Cm and 6.81? Cm. That is, it can be seen that the resistance is reduced to 1/100 level by doping copper oxide with nickel-manganese oxide. As the content of copper oxide increases, the resistance decreases.

FIG. 9 is a graph showing the resistance of nickel-manganese-copper oxide according to the content of copper oxide with temperature change.

9, the resistivities of the metal oxide thin films prepared according to Examples 5 to 9 of the present invention were 4.51? Cm, 0.99? 1.76? 占 ㎝ m and 1.83? 占 ㎝ m. The resistivity of the metal oxide thin film prepared according to Example 7 tends to be lowest at a temperature of 35 ° C or higher in the temperature range of 25 ° C to 55 ° C, . It is also confirmed that the resistivity of the metal oxide thin film produced according to Example 6 is lower than that of the metal oxide thin film prepared according to Examples 8 and 9 in the temperature range of 55 ° C to 85 ° C .

Referring to the TCR values, the metal oxide thin films prepared according to Examples 5 to 9 of the present invention have a value of about -4.57% / K to -1.41% / K at room temperature, It can be seen that it has a value of 3.05% / K to -1.09% / K.

In particular, in the case of the sample devices 2 and 5, when the TCR measured at room temperature and the TCR measured at about 80 ° C to 85 ° C were observed, the TCR value decreased when the temperature was increased, but the difference was about 0.02% / K. ≪ / RTI > It can be seen that the TCR value is not largely different even if it is set at a temperature higher than room temperature, and thus it is suitable to be widely used in electric devices and optical devices sensitive to temperature change. Also, in the case of the sample devices 1 and 4, when the temperature is increased, the TCR value is rather increased, and the difference is approximately 0.24% / K and 0.81% / K.

Claims (10)

Preparing a mixed solution by mixing a precursor solution containing nickel oxide and manganese oxide with an organic solvent;
Coating the mixed solution on a substrate to form a coating layer;
Baking the coating layer to form a seed layer; And
And crystallizing the seed layer at a temperature higher than 400 ° C and 800 ° C or lower to form a metal oxide thin film.
The method of claim 1, wherein forming the metal oxide thin film comprises:
Wherein the annealing is performed at a temperature ranging from 410 < 0 > C to 510 < 0 > C.
2. The method of claim 1, wherein forming the seed layer comprises:
Wherein the temperature is raised at a rate of 7 DEG C / min to 13 DEG C / min.
4. The method of manufacturing a metal oxide thin film according to claim 3, wherein the step of forming the seed layer has a temperature increase rate of 10 DEG C / min.
4. The method of claim 3, wherein forming the seed layer comprises:
Wherein the temperature is raised from 380 to 420 캜.
The method of claim 1, wherein in the precursor solution, the atomic ratio of nickel and oxygen of the nickel oxide is 1: 1, the atomic ratio of oxygen to manganese is 1: 1.5,
Wherein the metal oxide thin film comprises nickel-manganese oxide (NiMn ₂ O ₄ ).
The method according to claim 1,
Forming a coating layer on the seed layer using the mixed solution before forming the metal oxide thin film; And
And baking the coating layer on the seed layer. ≪ RTI ID = 0.0 > 11. < / RTI >
The method of claim 1, wherein the metal oxide thin film
Nickel-manganese oxide (NiMn ₂ O ₄ ).
The method of claim 1, wherein the precursor solution further comprises copper oxide (CuO)
Wherein the metal oxide thin film comprises nickel-manganese-copper oxide.
The method of claim 1, wherein the metal oxide thin film
Nickel-manganese-copper oxide ((1-x) NiMn ₂ O ₄ - (x) CuO, where 0.2 x 0.4).

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