Oxide thin film

Abstract

Provided is an oxide thin film exhibiting MIT characteristics with improved reliability, sensitivity, precision, and reproducibility. 【Solution means】The oxide thin film of the present invention includes a single crystal substrate and a main oxide layer laminated on the single crystal substrate and doped with a heterogeneous metal element. By energy dispersive X-ray analysis (EDX) using a transmission electron microscope (TEM), the heterogeneous metal element and the metal elements of the metal oxide constituting the main oxide layer are uniformly distributed, and the EDX curve distribution level of the heterogeneous metal element has a difference within 30% with respect to the EDX curve distribution level of the metal elements of the metal oxide constituting the main oxide layer. The standard deviation of the EDX curve of the heterogeneous metal element measured in the thickness direction of the main oxide layer has a difference within 30% with respect to the standard deviation of the EDX curve of the metal elements of the metal oxide constituting the main oxide layer.

Description

Technical Field

[0001] The present invention relates to an oxide thin film, and more particularly to an oxide thin film having a metal-insulator transition phenomenon (MIT characteristics).

Background Art

[0002] With the advent of the IoT (Internet of Things) era, most things have become electronic devices. Along with this, various electronic components such as transistors, diodes, memories, sensors, and capacitors have become more high-performance and miniaturized, and a larger number of electronic components are integrated into electronic devices. On the other hand, electronic devices containing more high-performance electronic components may be more vulnerable to abnormal internal and external stimuli such as overheating, overcurrent, and overvoltage. To solve such problems, it is conceivable to incorporate a surge protection module into an electronic device.

[0003] From such a perspective, there is an increasing interest in semiconductor materials characterized by a metal-insulator transition phenomenon (Metal-Insulator Transition; MIT) from an insulator to a metal induced by external energy stimulation. Among them, vanadium dioxide (VO2) is known to have a phase transition phenomenon at a temperature close to room temperature (about 67 °C) at ultra-high speed (within femto (10 -15 ) seconds). Vanadium dioxide (VO2) has great potential for application in sensing, switching, especially in the field of surge protection applications in that it is sensitive and responds quickly to various energies such as heat, electricity, and light.

[0004] In the case of single crystal bulk VO2, during the phase transition, rapid destruction occurs within several cycles accompanied by structural deformation and strain. Therefore, there may be limitations in using single crystal bulk VO2 in the fields described above. Thus, in order to ensure reliability such as repeatability and stability, it is necessary to fabricate high-quality VO2 thin films. For the VO2 thin film to have high sensitivity and high reliability characteristics, the difference in electrical resistance (R1 / R2) between the metal phase and the insulating phase of the VO2 thin film must be large, and the hysteresis temperature difference (ΔT), which is the difference between the phase transition temperature during the heating process and the phase transition temperature during the cooling process, must be small.

Summary of the Invention

Problems to be Solved by the Invention

[0005] The object of the present invention is to provide an oxide thin film exhibiting MIT characteristics with improved reliability, sensitivity, accuracy, and reproducibility.

Means for Solving the Problems

[0006] The oxide thin film includes a single crystal substrate and a main oxide layer laminated on the single crystal substrate and doped with a different metal element. In energy dispersive X-ray analysis (EDX) using a transmission electron microscope (TEM), the different metal element and the metal element of the metal oxide constituting the main oxide layer may be uniformly distributed. The EDX curve distribution level of the different metal element may have a difference within 30% with respect to the EDX curve distribution level of the metal element of the metal oxide constituting the main oxide layer.

[0007] The standard deviation of the EDX curve of the different metal element measured in the thickness direction of the main oxide layer may have a difference within 30% with respect to the standard deviation of the EDX curve of the metal element of the metal oxide constituting the main oxide layer. The main oxide layer may be formed by integrating a crystal sacrificial layer of the different metal element and a preliminary oxide thin film formed on the crystal sacrificial layer through a post-heat treatment process. The crystalline sacrificial layer may be grown on the single-crystalline substrate along the crystal direction of the single-crystalline substrate.

[0008] The preliminary oxide film may be a film that is amorphous on the crystalline sacrificial layer. The main oxide layer may be one in which the amorphous preliminary oxide film is crystallized in a predetermined direction along the crystal direction of the crystalline sacrificial layer by the post-heat treatment step. The single-crystalline substrate is a sapphire (Al2O3) single-crystalline substrate, and the main oxide layer may be one in which at least a part of V ions in the crystal lattice of VO2 is substituted (doped) with Ti ions. Further, the oxide film includes a single-crystalline substrate and a VO2 layer laminated on the single-crystalline substrate and doped with Ti. However, the VO2 XRD peak of the VO2 layer does not appear in the range of 2θ = 20 to 60 °C and appears only in the range of 2θ = 60 to 70 °C.

[0009] The VO2 layer can be defined as a highly crystalline epitaxial thin film in which one main VO2 XRD peak satisfying a certain intensity or more appears, rather than a polycrystalline thin film in which a large number of main VO2 XRD peaks appear in the range of 2θ = 20 to 70 °C. For the polycrystalline thin film, the main VO2 XRD peaks appear in two or more of the ranges of 2θ = 27.84 ± 0.5 °C, 2θ = 33.4 ± 0.5 °C, 2θ = 37.08 ± 0.5 °C, 2θ = 42.26 ± 0.5 °C, 2θ = 49.52 ± 0.5 °C, 2θ = 55.54 ± 0.5 °, 2θ = 57.64 ± 0.5 °C, and 2θ = 64.94 ± 0.5 °C. In contrast, for the epitaxial thin film, the main VO2 XRD peak appears only in the range of θ = 64.92 ± 0.5 °C. The full width at half maximum HWHM of the main VO2 XRD peak of the VO2 layer may be 1° or less.

Advantages of the Invention

[0010] According to the present invention, an oxide thin film exhibiting MIT characteristics with improved reliability, sensitivity, accuracy, and reproducibility can be provided.

Brief Description of the Drawings

[0011]

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Embodiments for Carrying Out the Invention

[0012] The terms used in this application are merely used to describe specific embodiments and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, terms such as "including" or "having" are used to specify the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and it should be understood that they do not preclude the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof. Also, throughout the specification, "above" means located above or below the target part, and does not necessarily mean located above with reference to the direction of gravity.

[0013] Also, the term "coupling" is used as a concept that includes not only the case where each component is physically in direct contact in the contact relationship between components, but also the case where other components are interposed between the components and the components are in contact with the other components respectively. The size and thickness of each component shown in the figures are arbitrarily shown for convenience of explanation, and the present invention is not necessarily limited to what is shown. In the figures, the first direction can be defined as the L direction or the length direction, the second direction can be defined as the W direction or the width direction, and the third direction can be defined as the T direction or the thickness direction. Hereinafter, a thin film substrate and an energy-sensitive electronic component according to embodiments of the present invention will be described in detail with reference to the accompanying drawings. When describing with reference to the accompanying drawings, the same or corresponding components are given the same drawing numbers, and duplicate descriptions thereof are omitted.

[0014] A variety of types of electronic components are used in electronic devices. For such electronic components, various types of energy-sensitive electronic components can be appropriately used for purposes such as preventing overheating or overvoltage. Energy-sensitive electronic components include, for example, a thermistor which is a heat energy-sensitive electronic component, a varistor which is an electrical energy-sensitive electronic component, etc., and can be used to protect various electronic devices, various electronic components of electronic devices, and modules of various electronic components. In this specification, an energy-sensitive electronic component means that the electrical resistance of the electronic component changes in response to changes in energy such as heat energy, electrical energy, light energy, etc. However, hereinafter, for convenience of explanation, it will be described on the premise that the energy-sensitive electronic component changes its electrical resistance in response to changes in heat energy, that is, changes its electrical resistance in response to temperature changes.

[0015] FIG. 1 is a diagram schematically showing an energy-sensitive electronic component. FIG. 2 is a diagram showing a cross section along the line I-I' of FIG. 1. FIG. 3 is a diagram showing a cross section along the line II-II' of FIG. 1. FIG. 4 is an enlarged view of A in FIG. 2. As shown in FIGS. 1 to 4, the electronic component (1000) includes a thin film substrate (100), a first external electrode (200), and a second external electrode (300). The thin film substrate (100) includes a base substrate (110) and a functional thin film (120). Hereinafter, for convenience of explanation, the "energy-sensitive electronic component (1000)" will be referred to as the "electronic component (1000)". The thin film substrate (100) can form the overall appearance of the electronic component (1000) according to this embodiment. The thin film substrate (100) can be formed in an overall hexahedral shape. Hereinafter, from the point that the thin film substrate (100) constitutes the overall appearance of the electronic component (1000) according to this embodiment, it will be referred to as the body (100).

[0016] With reference to FIGS. 1 to 3, the body (100) includes a first surface (101) facing the first direction (1), a second surface (102), a third surface (103) facing the second direction (2), a fourth surface (104), a fifth surface (105) facing the third direction (3), and a sixth surface (106). Each of the first to fourth surfaces (101, 102, 103, 104) of the body (100) corresponds to a wall surface of the body (100) that connects the fifth surface (105) and the sixth surface (106) of the body (100). Hereinafter, both end faces (one end face and the other end face) of the body (100) mean the first surface (101) and the second surface (102) of the body (100), both side faces (one end face and the other end face) of the body (100) mean the third surface (103) and the fourth surface (104) of the body (100), and one surface and the other surface of the body (100) mean the sixth surface (106) and the fifth surface (105) of the body (100), respectively.

[0017] On the other hand, since the body (100) includes the base substrate (110) and the functional thin film (120) disposed on the base substrate (110), each of the first to fourth surfaces (101, 102, 103, 104) of the body (100) can be composed of the base substrate (100) and the functional thin film (120). Also, the sixth surface (106) of the body (100) can be composed substantially only of the base substrate (100), and the fifth surface (105) of the body (100) can be composed substantially only of the functional thin film (120). When the electronic component (1000) according to the present embodiment is mounted on a mounting substrate such as a printed circuit board, it may be mounted such that the sixth surface (106) of the body (100) faces the upper surface of the mounting substrate, or it may be mounted such that the fifth surface (105) of the body (100) faces the upper surface of the mounting substrate.

[0018] The body (100) can be formed, for example, such that the electronic component (1000) according to the present embodiment on which external electrodes (200, 300) described later are formed has a length of 7.4 mm and a width of 5.1 mm, or a length of 6.3 mm and a width of 3.2 mm, or a length of 5.0 mm and a width of 2.5 mm, or a length of 4.5 mm and a width of 3.2 mm, or a length of 4.5 mm and a width of 1.6 mm, or a length of 3.2 mm and a width of 2.5 mm, or a length of 3.2 mm and a width of 1.6 mm, or a length of 2.5 mm and a width of 2.0 mm, or a length of 2.0 mm and a width of 1.2 mm, or a length of 1.6 mm and a width of 0.8 mm, or a length of 1.0 mm and a width of 0.5 mm, or a length of 0.8 mm and a width of 0.4 mm, or a length of 0.6 mm and a width of 0.3 mm, or a length of 0.4 mm and a width of 0.2 mm, but is not limited thereto.

[0019] On the other hand, since the above-described exemplary numerical values regarding the length and width of the electronic component (1000) are values that do not reflect the process error, numerical values within the range recognized as the process error should be regarded as corresponding to the above-described exemplary numerical values. Further, since the body (100) of the electronic component (1000) can be formed by forming the functional thin film (120) on the wafer-state base substrate (110) and then dicing the wafer-state base substrate (110), the length and width of the electronic component (1000) may be substantially the same as the length and width of the base substrate (110) and the length and width of the functional thin film (120).

[0020] Here, the length of the electronic component (1000) is based on an optical microscope or SEM photograph of the cross-section (1-3 cross-section) of the electronic component (1000) taken in the first direction (1) - third direction (3) from the central part of the electronic component (1000) in the second direction (2). Among the outermost boundary lines of the electronic component (1000) shown in the photograph, it may mean the maximum value among the numerical values (dimensions) along the first direction (1) of each of a plurality of line segments parallel to the first direction (1) by connecting two boundary lines facing the first direction (1). Alternatively, the length of the electronic component (1000) may mean the minimum value among the numerical values (dimensions) along the first direction (1) of each of a plurality of line segments parallel to the first direction (1) by connecting two boundary lines facing the first direction (1) among the outermost boundary lines of the electronic component (1000) shown in the photograph. Alternatively, it may mean the arithmetic mean value for the numerical values (dimensions) along the first direction (1) of at least two of a plurality of line segments parallel to the first direction (1) by connecting two boundary lines facing the first direction (1) among the outermost boundary lines of the electronic component (1000) shown in the photograph.

[0021] Here, the width of the electronic component (1000) is based on an optical microscope photograph or an SEM photograph of the cross-section (1-2 cross-section) of the electronic component (1000) taken in the first direction (1)-second direction (2) from the central part of the electronic component (1000) in the third direction (3). Among the outermost boundary lines of the electronic component (1000) shown in the cross-section photograph, two boundary lines facing each other in the second direction (2) are connected, and among the numerical values (dimensions) along the second direction (2) of each of a plurality of line segments parallel to the second direction (2), it may mean the maximum value. Alternatively, among the outermost boundary lines of the electronic component (1000) shown in the cross-section photograph, two boundary lines facing each other in the second direction (2) are connected, and among the numerical values (dimensions) along the second direction (2) of each of a plurality of line segments parallel to the second direction (2), it may mean the minimum value. Alternatively, among the outermost boundary lines of the electronic component (1000) shown in the cross-section photograph, two boundary lines facing each other in the second direction (2) are connected, and it may mean the arithmetic mean value for the numerical values (dimensions) along the second direction (2) of at least two of a plurality of line segments parallel to the second direction (2).

[0022] Here, the thickness of the electronic component (1000) is based on an optical microscope or SEM photograph of the cross-section (1-3 cross-section) of the electronic component (1000) taken in the first direction (1)-third direction (3) from the central part of the electronic component (1000) in the second direction (2). Among the outermost boundary lines of the electronic component (1000) shown in the cross-section photograph, two boundary lines facing each other in the third direction (3) are connected. Among the numerical values (dimensions) along the third direction (3) of each of the plurality of line segments parallel to the third direction (3), it may mean the maximum value. Alternatively, among the outermost boundary lines of the electronic component (1000) shown in the cross-section photograph, two boundary lines facing each other in the third direction (3) are connected. Among the numerical values (dimensions) along the third direction (3) of each of the plurality of line segments parallel to the third direction (3), it may mean the minimum value. Alternatively, among the outermost boundary lines of the electronic component (1000) shown in the cross-section photograph, two boundary lines facing each other in the third direction (3) are connected. Among the plurality of line segments parallel to the third direction (3), it may mean the arithmetic mean value of the numerical values (dimensions) along at least two third directions (3).

[0023] Alternatively, the length, width, and thickness of the electronic component (1000) can also be measured by the micrometer measurement method. The micrometer measurement method can set the zero point with a Gage R&R (Repeatability and Reproducibility) micrometer, insert the electronic component (1000) according to this embodiment between the tips of the micrometer, and turn the measurement lever of the micrometer to measure. On the other hand, when measuring the length of the electronic component (1000) by the micrometer measurement method, the length of the electronic component (1000) can mean the value measured once, or can also mean the arithmetic mean of the values measured multiple times. This can be similarly applied to the width and thickness of the electronic component (1000).

[0024] The body (100) includes a base substrate (110) and a functional thin film (120). Specifically, the body (100) includes a base substrate (110) and a functional thin film (120) disposed on one surface of the base substrate (110) (the upper surface of the base substrate (110) based on the directions of FIGS. 1 to 3). The base substrate (110) may be a single crystal substrate. The base substrate (110) may grow in one direction and have crystallinity. For example, the base substrate (110) may be an Al2O3 single crystal substrate, an Si single crystal substrate, an SiC single crystal substrate, a Ge single crystal substrate, a TiO2 single crystal substrate, a ZnO single crystal substrate, a ZnS single crystal substrate, a ZnSe single crystal substrate, a ZnTe single crystal substrate, a CdS single crystal substrate, a CdSe single crystal substrate, a CdTe single crystal substrate, a GaAs single crystal substrate, a GaP single crystal substrate, a GaSb single crystal substrate, an InAs single crystal substrate, an InP single crystal substrate, an SrTiO3 single crystal substrate, or an MgO single crystal substrate.

[0025] The functional thin film (120) may be a thin film of VO2 doped with Ti. As a non-limiting example, the functional thin film (120) can be formed on the base substrate (110) by forming a sacrificial layer of TiO2 on the base substrate (110), forming a main oxide thin film layer of VO2 on the sacrificial layer, and post-heat-treating the sacrificial layer and the main oxide thin film layer. Here, the sacrificial layer can grow in a certain direction along the crystal direction of the base substrate (110) on the upper surface of the base substrate (110). That is, the sacrificial layer may be pre-crystallized before forming the main oxide thin film layer. The thickness of the sacrificial layer may be, for example, 1 nm to 50 nm, but the scope of the present invention is not limited thereto and can be appropriately changed according to the Ti ion concentration in the designed functional thin film (120). The sacrificial layer can be formed through thin film processes such as physical vapor deposition methods (PECVD) such as sputtering, pulsed laser deposition (PLD), electron beam evaporation (e-beam evaporator), chemical vapor deposition methods (PECVD, MOCVD), atomic layer deposition (ALD), and molecular beam epitaxy (MBE).

[0026] Here, the main oxide thin film layer may be crystallized in a certain direction along the crystal direction of the sacrificial layer on the sacrificial layer, or may be non-crystallized. When a post-heat treatment process is performed after forming the main oxide thin film layer, the main oxide thin film layer can be formed in an amorphous state on the sacrificial layer. The thickness of the main oxide thin film layer may be, for example, 10 nm to 1000 nm, but the scope of the present invention is not limited thereto and can be appropriately changed according to the Ti ion concentration in the designed functional thin film (120). The main oxide thin film layer can be formed through thin film processes such as physical vapor deposition methods (PECVD) such as sputtering, pulsed laser deposition (PLD), electron beam evaporation (e-beam evaporator), chemical vapor deposition methods (PECVD, MOCVD), atomic layer deposition (ALD), and molecular beam epitaxy (MBE).

[0027] Here, the post-heat treatment may be a process for integrating the sacrificial layer and the main oxide thin film layer. Specifically, the post-heat treatment may be an integration process in which the substance constituting the sacrificial layer is doped into the main oxide thin film layer and the boundary between the sacrificial layer and the main oxide thin film layer is removed. The post-heat treatment can be performed using, for example, a device such as a box furnace, a tube furnace, or a rapid thermal annealing furnace (RTA). The post-heat treatment can be performed in an atmosphere of one or more of, for example, air, oxygen (O2), nitrogen (N2), argon (Ar), and hydrogen (H2). The post-heat treatment can be performed in a temperature range of, for example, 400 °C to 800 °C. This is a method of depositing the main oxide layer at a low temperature and then performing post-heat treatment, which has advantages in the configuration of the vacuum chamber, reduces variables due to temperature during deposition, and is advantageous in terms of thin film reproducibility. The functional thin film (120) formed through the post-heat treatment process can have its crystal structure and orientation determined by, for example, the crystal structure and orientation of the sacrificial layer. For example, the functional thin film (120) integrated by post-heat treating the sacrificial layer and the main oxide thin film layer can crystallize in a certain direction along the crystal orientation of the sacrificial layer before the post-heat treatment. At this time, the crystal orientations of the functional thin film (120) and the sacrificial layer are not necessarily the same.

[0028] For example, the functional thin film (120) can have substantially the same crystal lattice spacing as the sacrificial layer, but can grow and crystallize in a direction different from that of the crystalline sacrificial layer. Also, because the metal ion radius of the sacrificial layer and the metal ion radius of the main oxide thin film layer are similar (Ti 4+ ion radius is 0.60 Å; V 4+ ion radius is 0.58 Å), the metal ions of the sacrificial layer can self-diffuse without substantially deforming the crystal structure of VO2 during the post-heat treatment process. That is, the sacrificial layer and the main oxide layer may have a crystal lattice difference of 1% or less at the bonding surface, and the difference between the metal ion radius of the sacrificial layer and the metal ion radius of the main oxide layer may be 5% or less. This is to enable the metal ions to self-diffuse without the crystal structure deforming during the post-heat treatment process. Regarding the functional thin film (120), if the resistance at 25 °C is R1 and the resistance at 80 °C is R2, R1 / R2 may be 10 4 or more. The R1 / R2 of the functional thin film (120) may be, for example, 17000 or more. By making R1 / R2 of the functional thin film (120) 10 4 or more, the electronic component (1000) according to this embodiment can more sensitively detect energy changes at temperatures in the range of 25 °C to 80 °C.

[0029] When the temperature increase process from 25 °C to 80 °C and the cooling process from 80 °C to 25 °C of the functional thin film (120) are taken as one cycle, a) the change (V △T ) in the hysteresis temperature difference (ΔT) during 10 cycles is 1 °C or less, b) the change (V MI ) in the phase transition temperature (T TMI) is 1.5 °C or less, and c) the change rate of R1 / R2 during 10 cycles (V R1 / R2 ) can satisfy at least one of being 5% or less. Here, the hysteresis temperature difference (ΔT) of the functional thin film (120) is, based on any one cycle, the temperature at which the absolute value of the temperature coefficient of resistance (Temperature Coefficient of Resistance, TCR) of the functional thin film (120) defined by the following formula 1 is the maximum during the heating process is T H And, the temperature at which the absolute value of the temperature coefficient of resistance (TCR) of the functional thin film (120) defined by the following formula 1 is the maximum during the cooling process is T C When this is the case, T H And T C It can mean the difference from. The hysteresis temperature difference (ΔT) of the functional thin film (120) may be 1 °C or less, for example, may be 0.726 °C or less. When the hysteresis temperature difference (ΔT) of the functional thin film (120) is 1 °C or less, the functional thin film (120) can be regarded as having substantially no thermal hysteresis phenomenon during the cycle.

[0030] As a result, within the temperature range of the heating and cooling processes, the functional thin film (120) may have substantially the same temperature during the heating process and the cooling process for the same resistance. Therefore, different from ordinary electronic components in which the temperature changes depending on whether it is a heating process or a cooling process even with the same resistance, the electronic component (1000) according to the present embodiment can relatively accurately detect energy changes.

[0031] [Formula 1] TIFF2025519767000002.tif22163 Also, the change in the hysteresis temperature difference (ΔT) of the functional thin film (120) during 10 cycles (V △T ) can, for example, when the heating process and the cooling process from the first cycle to the tenth cycle are performed on the functional thin film (120), mean the difference between the maximum value and the minimum value of the hysteresis temperature differences (ΔT1, ΔT2,..., ΔT10) of the functional thin film (120) obtained for each of the first cycle to the tenth cycle (V△T = |Max(ΔT1, ΔT2, ..., ΔT10) - Min(ΔT1, ΔT2, ..., ΔT10)|). Or, the change (V △T ) in the hysteresis temperature difference (ΔT) during 10 cycles of the functional thin film (120) is, for example, when the functional thin film (120) is subjected to a heating process and a cooling process from the first cycle to the tenth cycle, the hysteresis temperature difference (ΔT1) of the functional thin film (120) in the first cycle and the hysteresis temperature difference (ΔT10) of the functional thin film (120) in the tenth cycle, and can mean the difference therebetween (V △T = |ΔT1 - ΔT10|).

[0032] The change (V △T ) in the hysteresis temperature difference (ΔT) during 10 cycles of the functional thin film (120) is 1°C or less, the functional thin film (120) can be regarded as having a substantially constant hysteresis temperature difference (ΔT) even when the number of cycles increases. As a result, the functional thin film (120) can accurately sense repeated and stable energy changes within the temperature range of the heating and cooling processes. Therefore, the electronic component (1000) according to the present embodiment can improve the repetitive reproducibility with respect to accuracy.

[0033] Here, the phase transition temperature (T MI ) of the functional thin film (120) can be defined by the following formula 2. That is, the phase transition temperature (T MI ) of the functional thin film (120) can mean half of the difference between T H and T C in any one cycle. The phase transition temperature (T MI ) of the functional thin film (120) may be 54°C or less, for example, 52.4°C, 53.1°C, 53.5°C, but the scope of the present invention is not limited thereto. Specifically, the phase transition temperature (T MI ) of the functional thin film (120) is variable depending on the content of Ti ions doped in the functional thin film (120). The phase transition temperature (T MI) is 54°C or lower, the Metal-Insulator Transition (MIT) phenomenon can be utilized in the relatively low-temperature region. Therefore, the electronic component (1000) according to the present embodiment can be used as a switching component in the relatively low-temperature region.

[0034] [Equation 2] TIFF2025519767000003.tif20114 Also, the phase transition temperature (T MI ) change (VT MI ) of the functional thin film (120) during 10 cycles, for example, when the functional thin film (120) is subjected to a heating process and a cooling process from the first cycle to the tenth cycle, the phase transition temperature (T MI1 , T MI2 ,..., T MI10 ) of the functional thin film (120) obtained in each of the first cycle to the tenth cycle can mean the difference between the maximum value and the minimum value (V TMI = │ MI1 , T MI2 ,..., T MI10 ) - Min(T MI1 , T MI2 ,..., T MI10 ) │). Or, the phase transition temperature (T MI ) change (V TMI ) of the functional thin film (120) during 10 cycles, for example, when the functional thin film (120) is subjected to a heating process and a cooling process from the first cycle to the tenth cycle, can mean the difference between the phase transition temperature (T MI1 ) of the functional thin film (120) in the first cycle and the phase transition temperature (T MI10 ) of the functional thin film (120) in the tenth cycle (V TMI = │ MI1 - T MI10 │). When the change (V MI ) of the phase transition temperature (T TMI ) of the functional thin film (120) during 10 cycles is 1.5°C or lower, the functional thin film (120) can be regarded as having a substantially constant phase transition temperature (T MI ) even when the number of cycles increases.

[0035] As a result, the functional thin film (120) can repeatedly and stably implement the switching function within the temperature range of the heating and cooling processes. Therefore, the electronic component (1000) according to the present embodiment can be repeatedly used as a switching component in a relatively low temperature region regardless of the number of operating times. Here, the change rate (V R1 / R2 ) of R1 / R2 during 10 cycles of the functional thin film (120) means, for example, when the heating and cooling processes from the first cycle to the tenth cycle are performed on the functional thin film (120), the R1 / R2 values ((R1 / R2)1, (R1 / R2)2,..., (R1 / R2) 10 ) of the functional thin film (120) obtained in each of the first cycle to the tenth cycle, and the percentage obtained by dividing the difference between the maximum value and the minimum value by the maximum value (V R1 / R2 = 100 * (│)1, (R1 / R2)2,..., (R1 / R2) 10 ) - Min((R1 / R2)1, (R1 / R2)2,..., (R1 / R2) 10 )) / Max((R1 / R2)1, (R1 / R2)2,..., (R1 / R2) 10 ).

[0036] Alternatively, the change rate (V R1 / R2 ) of R1 / R2 during 10 cycles of the functional thin film (120) means, for example, when the heating and cooling processes from the first cycle to 10 cycles are performed on the functional thin film (120), the percentage of the difference between the R1 / R2 value ((R1 / R2)1) of the functional thin film (120) in the first cycle and the R1 / R2 value ((R1 / R2) 10 ) of the functional thin film (120) in the tenth cycle with respect to the R1 / R2 value ((R1 / R2)1) of the functional thin film (120) in the first cycle (V R1 / R2 = 100 * (│1 - (R1 / R2) 10 │) / (R1 / R2)1). The change rate (V R1 / R2) is 5% or less, the functional thin film (120) can be regarded as having a substantially constant value of R1 / R2 even as the cycle increases. As a result, the functional thin film (120) can sensitively sense energy changes repeatedly and stably within the temperature range of the heating and cooling processes. Therefore, the electronic component (1000) according to the present embodiment can improve the repeatability of sensitivity.

[0037] The external electrodes (200, 300) are arranged on the body (100) so as to be spaced apart from each other. That is, the external electrodes (200, 300) are arranged in a form spaced apart from each other on the base substrate (110) and / or the functional thin film (120). Each of the external electrodes (200, 300) is in contact with and connected to the functional thin film (120). The external electrodes (200, 300) can be formed by at least one of vapor deposition methods such as sputtering, plating methods, and methods of curing after applying a conductive paste. The external electrodes (200, 300) can contain conductive substances such as platinum (Pt), gold (Au), chromium (Cr), molybdenum (Mo), nickel (Ni), titanium (Ti), silver (Ag), aluminum (Al), copper (Cu), iron (Fe), indium (In), tin (Sn), lead (Pb), palladium (Pd), zinc (Zn), and cobalt (Co), or alloys thereof. The external electrodes (200, 300) can be formed in a single-layer or multi-layer structure.

[0038] The external electrodes (200, 300) include conductive resin layers (210, 310) and metal layers (220, 320) formed on the conductive resin layers (210, 310). Specifically, the first external electrode (200) includes a first conductive resin layer (210) formed on the body (100) and a first metal layer (220) formed on the first conductive resin layer (210). The second external electrode (300) includes a second conductive resin layer (310) formed on the body (100) and a second metal layer (320). The first conductive resin layer (210) is disposed on the first surface (101) of the body (100) and extends to at least a part of each of the third to sixth surfaces (103, 104, 105, 106) of the body (100). The first conductive resin layer (210) is in contact with one end portion on the first surface (101) side of the body (100) of the functional thin film (120). The second conductive resin layer (310) is disposed on the second surface (102) of the body (100) and extends to at least a part of each of the third to sixth surfaces (103, 104, 105, 106) of the body (100). The second conductive resin layer (310) is in contact with the other end portion on the second surface (102) side of the body (100) of the functional thin film (120).

[0039] The first and second conductive resin layers (210, 310) are disposed separately from each other on each of the third to sixth surfaces (103, 104, 105, 106) of the body (100). On the other hand, in FIGS. 1 to 3, each of the conductive resin layers (210, 310) is shown in a Normal type formed on five surfaces of the body (100), but this is merely an illustrative matter. That is, each of the conductive resin layers (210, 310) can be deformed into one of a C type (for example, a form in which the first conductive resin layer (210) is disposed only on the first surface (101), the fifth surface (105), and the sixth surface (106) of the body (100)), an L type (for example, the first conductive resin layer (210) is disposed only on the first surface (101) and the fifth surface (105) of the body (100), or is disposed only on the first surface (101) and the sixth surface (106) of the body (100)), and a bottom electrode type (for example, the first conductive resin layer (210) is disposed only on the fifth surface (105) of the body (100)) according to the design.

[0040] The conductive resin layers (210, 310) include a base resin (R) and conductive particles (CP) dispersed in the base resin (R). The conductive particles (CP) are in contact with each other and connected within the base resin (R), and can connect the external electrodes (200, 300) and the functional thin film (120) to each other. The conductive resin layers (210, 310) can be formed by applying a conductive paste for forming a conductive resin layer to the body (100) and then curing the conductive paste. The base resin (R) can include a thermosetting resin having electrical insulation properties. The thermosetting resin may be, for example, an epoxy resin, but the present invention is not limited thereto.

[0041] The conductive particles (CP) can include at least one of platinum (Pt), gold (Au), chromium (Cr), molybdenum (Mo), nickel (Ni), titanium (Ti), silver (Ag), aluminum (Al), copper (Cu), iron (Fe), indium (In), tin (Sn), lead (Pb), palladium (Pd), zinc (Zn), and cobalt (Co). As non-limiting examples, the conductive particles (CP) can include platinum (Pt) particles, gold (Au) particles, chromium (Cr) particles, molybdenum (Mo) particles, nickel (Ni) particles, titanium (Ti) particles, silver (Ag) particles, aluminum (Al) particles, copper (Cu) particles, iron (Fe) particles, indium (In) particles, tin (Sn) particles, lead (Pb) particles, palladium (Pd) particles, zinc (Zn) particles, cobalt (Co) particles, and at least one of alloy particles composed of at least two of the above metals.

[0042] As another example, the conductive particles (CP) may have a core-shell structure. Here, the core can include at least one of platinum (Pt), gold (Au), chromium (Cr), molybdenum (Mo), nickel (Ni), titanium (Ti), silver (Ag), aluminum (Al), copper (Cu), iron (Fe), indium (In), tin (Sn), lead (Pb), palladium (Pd), zinc (Zn), and cobalt (Co), and the shell can include at least one of platinum (Pt), gold (Au), chromium (Cr), molybdenum (Mo), nickel (Ni), titanium (Ti), silver (Ag), aluminum (Al), copper (Cu), iron (Fe), indium (In), tin (Sn), lead (Pb), palladium (Pd), zinc (Zn), and cobalt (Co).

[0043] The conductive particles (CP) may be spherical and / or flaky. By "flaky" it means that the dimension along any one of the first to third directions (1, 2, 3) is 1.5 times or more larger than the dimension along any other of the first to third directions (1, 2, 3). Here, the direction of the larger of the two dimensions can be defined as the major axis, and the direction of the smaller of the two dimensions can be defined as the minor axis. The metal layers (220, 320) can be formed on the conductive resin layers (210, 310). At least a part of each of the metal layers (220, 320) is disposed in the region formed on the mounting surface of the electronic component (1000) according to this embodiment in the conductive resin layers (210, 320).

[0044] For example, when the mounting surface of the electronic component (1000) is on the fifth surface (105) side of the body (100), the first metal layer (220) may be formed in a region of the first conductive resin layer (210) that is disposed on the fifth surface (105) of the body (100), and the second metal layer (320) may be formed in a region of the second conductive resin layer (310) that is disposed on the fifth surface (105) of the body (100). At this time, the first metal layer (220) may be formed on at least a part of the first surface (101), the third surface (103), the fourth surface (104), and the sixth surface (106) of the body (100). Alternatively, even if the first conductive resin layer (210) extends to each of the first surface (101), the third surface (103), the fourth surface (104), and the sixth surface (106) of the body (100), the first metal layer (220) may not be formed on at least a part of the first surface (101), the third surface (103), the fourth surface (104), and the sixth surface (106) of the body (100). At this time, the second metal layer (320) may be formed on at least a part of the second surface (102), the third surface (103), the fourth surface (104), and the sixth surface (106) of the body (100).

[0045] Alternatively, even if the second conductive resin layer (310) extends to each of the second surface (102), the third surface (103), the fourth surface (104), and the sixth surface (106) of the body (100), the second metal layer (320) may not be formed on at least a part of the second surface (102), the third surface (103), the fourth surface (104), and the sixth surface (106) of the body (100). As another example, when the mounting surface of the electronic component (1000) is on the sixth surface (106) side of the body (100), the first metal layer (220) may be formed in a region of the first conductive resin layer (210) that is disposed on the sixth surface (106) of the body (100), and the second metal layer (320) may be formed in a region of the second conductive resin layer (310) that is disposed on the sixth surface (106) of the body (100). At this time, the first metal layer (220) can be formed on at least a part of the first surface (101) and the third to fifth surfaces (103, 104, 105) of the body (100).

[0046] Alternatively, even if the first conductive resin layer (210) extends to the first surface (101) and the third to fifth surfaces (103, 104, 105) of the body (100) respectively, the first metal layer (220) may not be formed on at least a part of the first surface (101) and the third to fifth surfaces (103, 104, 105) of the body (100). At this time, the second metal layer (320) may be formed on at least a part of the second to fifth surfaces (102, 103, 103, 104, 105) of the body (100). Or, even if the second conductive resin layer (310) extends to the second to fifth surfaces (102, 103, 104, 105) of the body (100) respectively, the second metal layer (320) may not be formed on at least a part of the second to fifth surfaces (102, 103, 104, 105) of the body (100).

[0047] Each of the metal layers (220, 320) can include at least one of platinum (Pt), gold (Au), chromium (Cr), molybdenum (Mo), nickel (Ni), titanium (Ti), silver (Ag), aluminum (Al), copper (Cu), iron (Fe), indium (In), tin (Sn), lead (Pb), palladium (Pd), zinc (Zn), and cobalt (Co). Each of the metal layers (220, 320) may be formed as a single layer or a multi-layer. The metal layers (220, 320) may be formed by at least one of vapor deposition methods such as sputtering and plating methods. As a non-limiting example, each of the metal layers (220, 320) may include a first plating layer (221, 321) formed on the conductive resin layers (210, 310), and a second plating layer (222, 322) formed on the first plating layer (221, 321). As a non-limiting example, the first plating layer (221, 321) may be a nickel plating layer, and the second plating layer (222, 322) may be a tin plating layer.

[0048] On the other hand, when the regions where the conductive resin layers (210, 310) are formed and the regions where the metal layers (220, 320) are formed on the first to sixth surfaces (101, 102, 103, 104, 105, 106) of the body (100) are different from each other, for example, between the step of forming the conductive resin layers (210, 310) and the step of forming the metal layers (220, 320), a step of forming a resist that exposes only a part of the outer surfaces of the conductive resin layers (210, 310) can be added.

[0049] Experimental Example (Manufacturing Methods of Experimental Examples 1 and 2) Experimental Example 1 was manufactured by the following method. First, a TiO2 thin film (thickness: 3 nm to 5 nm) was formed as a sacrificial layer on a sapphire (Al2O3) single crystal substrate by a sputtering process. Next, a VO2 thin film (thickness: 200 nm to 300 nm) was formed as a main oxide thin film layer on the sacrificial layer by a sputtering process. To form the VO2 thin film, the process temperature was normal temperature, the process pressure was 10 to 30 mtorr, and Ar gas was supplied for vapor deposition. Next, the sacrificial layer and the main oxide thin film layer were post-annealed at 400 to 800 °C to produce a functional thin film in which at least a part of the V ions in the crystal lattice of VO2 was substituted (doped) with Ti ions. Hereinafter, the thin film (functional thin film) finally manufactured according to Experimental Example 1 is referred to as the first thin film.

[0050] Experimental Example 2 was manufactured in the same manner as Experimental Example 1, except that the sacrificial layer of Experimental Example 1 was not deposited. That is, in Experimental Example 2, a main oxide thin film layer (VO2) was formed directly on the sapphire (Al2O3) single crystal substrate used in Experimental Example 1 under the same conditions as the film formation conditions of the main oxide thin film layer of Experimental Example 1, and then the main oxide thin film layer was post-annealed under the same conditions as the post-annealing conditions of Experimental Example 1. Hereinafter, the thin film finally manufactured by Experimental Example 2 (the post-annealed main oxide thin film layer) is referred to as the second thin film.

[0051] (Evaluation of the Characteristics of the First and Second Thin Films with Respect to Thermal Cycles) For each of the first and second thin films, a plurality of thermal cycles consisting of a heating process from 25°C to 80°C and a cooling process from 80°C to 25°C were performed, and the resistance of each of the first and second thin films according to temperature was measured. The heating and cooling of the first and second thin films were realized by attaching a heater that generates heat to the lower part of the sapphire substrate on which each of the first and second thin films was formed and adjusting the power applied to the heater. Specifically, the first and second thin films were heated by supplying power to the heater at room temperature (25°C), and when the first and second thin films reached 80°C, the power to the heater was cut off to cool the first and second thin films.

[0052] The surface temperature of the first and second thin films was measured with a Keithley nanovoltmeter (model name Keithley 2182A) by attaching an Omega contact temperature measurement probe (k-type thermocouple; 0.005 inches thermocouple wire) to each of the first and second thin films. The electrical resistances of the first and second thin films were derived by applying a constant voltage to the first and second thin films using a product of Keithley Instruments, Inc. (model name Keithley 2400) as a source meter, measuring the currents of the first and second thin films at the voltage, and then converting this into electrical resistance (R = V / I). At this time, in order to reduce the contact resistance between each of the first and second thin films and the metal probe for measuring the current, a metal thin film was formed with a thickness of 100 nm in a partial region of the first and second thin films, and the current was measured by bringing the metal thin film into contact with the metal probe.

[0053] The resistance due to temperature during the first cycle of each of the first and second thin films is shown in FIG. 5. In FIG. 5, the first thin film is indicated by "〇", and the second thin film is indicated by "△". The resistance due to temperature during multiple cycles of the first thin film is shown in FIG. 6. FIG. 7 is a graph with the number of thermal cycles on the X-axis and R1 / R2, the hysteresis temperature difference (ΔT), and the phase transition temperature (T MI ) of the first thin film on the Y-axis, respectively. In FIG. 7, "□" indicates R1 / R2, "X" indicates the hysteresis temperature difference (ΔT, unit: °C), and "●" indicates the phase transition temperature (TMI, unit: °C).

[0054] In Table 1, based on FIG. 5, in the first cycle, the resistance R1 at 25°C, the resistance R2 at 80°C, the temperature T at which the absolute value of the temperature coefficient of resistance (TCR) becomes maximum during the heating process, H the temperature T at which the absolute value of the temperature coefficient of resistance (TCR) becomes maximum during the cooling process, C R1 / R2, the hysteresis temperature difference (ΔT), and the phase transition temperature (T MI ) of each of the first and second thin films are listed.

[0055]

Table 1

[0056] As shown in Table 1, the second thin film has a hysteresis temperature difference (ΔT) of 11.41°C, which exceeds 1°C. The first thin film has a hysteresis temperature difference (ΔT) of 0.043°C, which is 1°C or less. This means that the difference between the temperature during the heating process and the temperature during the cooling process for the same resistance is relatively larger for the second thin film and relatively smaller for the first thin film. Therefore, the electronic component using the first thin film can detect temperature more accurately than the electronic component using the second thin film.

[0057] As shown in Table 1 and Figure 5, it can be seen that the maximum value of the temperature coefficient of resistance (TCR) of the first thin film is larger than the maximum value of the temperature coefficient of resistance (TCR) of the second thin film. This indicates that the resistance change of the first thin film due to temperature change is larger than that of the second thin film. Therefore, the sensitivity of the first thin film to temperature change near its phase transition temperature (T MI ) is higher than the sensitivity of the second thin film to temperature change near its phase transition temperature (T MI ). As shown in Table 1, the phase transition temperature (T MI ) of the first thin film is relatively lower than the phase transition temperature (T MI ) of the second thin film. This means that the first thin film transitions from an insulator to a conductor at a relatively lower temperature compared to the second thin film (Metal-Insulator Transition). Therefore, the electronic component using the first thin film can be used as a switching component at a relatively lower temperature compared to the electronic component using the second thin film.

[0058] Table 2 shows, based on FIGS. 6 and 7, for each cycle of the first thin film, R1 / R2, the hysteresis temperature difference (ΔT), and the phase transition temperature (T MI ), the change in the hysteresis temperature difference (ΔT) (V ΔT ) over 10 cycles, the change in the phase transition temperature (T MI ) over 10 cycles (V TMI ), and the change rate of R1 / R2 over 10 cycles (V R1 / R2 ). On the other hand, in Table 2, the change in the hysteresis temperature difference (ΔT) (V ΔT ) over 10 cycles, for example, with reference to the section from the first cycle to the tenth cycle, means the difference between the hysteresis temperature difference (ΔT) of the first cycle, which is the first cycle of the section, and the hysteresis temperature difference (ΔT) of the tenth cycle, which is the last cycle of the section (V ΔT = |ΔT1 - ΔT10|). This is similarly applicable to the change in the phase transition temperature (T MI ) over 10 cycles (V TMI ). Furthermore, in Table 2, the change rate of R1 / R2 (V R1 / R2 ) over 10 cycles, for example, with reference to the section from the first cycle to the tenth cycle, means the percentage of the difference between the R1 / R2 value ((R1 / R2)1) of the first cycle, which is the first cycle of the section, and the R1 / R2 value ((R1 / R2) 10 ) of the tenth cycle, which is the last cycle of the section, with respect to the R1 / R2 value ((R1 / R2)1) of the first cycle of the section (V R1 / R2 = 100*(|(R1 / R2)1 - (R1 / R2) 10 |) / (R1 / R2)1).

[0059] Also, in the following description of Table 2, the section from the first cycle to the tenth cycle is defined as the first section, the section from the eleventh cycle to the twentieth cycle is defined as the second section, the section from the twenty - first cycle to the thirtieth cycle is defined as the third section, the section from the thirty - first cycle to the fortieth cycle is defined as the fourth section, and the section from the forty - first cycle to the fiftieth cycle is defined as the fifth section for explanation.

[0060]

Table 2

[0061] As shown in Table 2, the change (V ΔT ) in the hysteresis temperature difference (ΔT) during 10 cycles of the first thin film is 0.304 °C in the first section, 0.249 °C in the second section, 0.330 °C in the third section, 0.197 °C in the fourth section, and 0.236 °C in the fifth section. That is, the first thin film has a change (V ΔT ) in the hysteresis temperature difference (ΔT) during 10 cycles of 1 °C or less throughout the first to fifth sections, and is considered to have a substantially constant hysteresis temperature difference (ΔT) regardless of the section. As a result, the first thin film can accurately sense repeated and stable energy changes within the temperature range of the heating and cooling processes.

[0062] As shown in Table 2, the change (V MI ) in the phase transition temperature (T TMI ) during 10 cycles of the first thin film is 0.14 °C in the first section, 0.249 °C in the second section, 0.43 °C in the third section, 0.56 °C in the fourth section, and 0.60 °C in the fifth section. That is, the first thin film has a change (V MI ) in the phase transition temperature (T TMI ) during 10 cycles of 1.5 °C or less throughout the first to fifth sections, and is considered to have a substantially constant phase transition temperature (T MI ) regardless of the section. As a result, the first thin film can repeatedly and stably exhibit a switching function at substantially the same temperature within the temperature range of the heating and cooling processes.

[0063] As shown in Table 2, the change rate of R1 / R2 (V R1 / R2) is 0.66% in the case of the first interval, 0.29% in the case of the second interval, 0.46% in the case of the third interval, 0.84% in the case of the fourth interval, and 1.28% in the case of the fifth interval. That is, the first thin film has a change rate of R1 / R2 (VR R1 / R2 ) within 5% during 10 cycles in the entire first to fifth intervals, and is regarded as having a substantially constant value of R1 / R2 regardless of which interval it is. As a result, the first thin film (120) can sensitively sense energy changes repeatedly and stably within the temperature range of the heating and cooling processes.

[0064] On the other hand, in the above, with respect to the first to fifth intervals, that is, based on the first to fiftieth cycles, the change rate of R1 / R2 (V R1 / R2 ) during 10 cycles of the first thin film, the change (V ΔT ) in the hysteresis temperature difference (ΔT) during 10 cycles of the first thin film, and the change (V MI ) in the phase transition temperature (T TMI ) during 10 cycles of the first thin film were described, but this is merely exemplary and the scope of the present invention is not limited to the above-described content. That is, as shown in FIG. 7, as long as it is within the first to fiftieth cycles, the first thin film also has, in any 10 cycles other than the above-described first to fifth intervals (for example, 10 cycles composed of the third cycle to the twelfth cycle), the change rate of R1 / R2 (V R1 / R2 ) during the above-described 10 cycles, the change (V ΔT ) in the hysteresis temperature difference (ΔT) during 10 cycles, and the change (V MI ) in the phase transition temperature (T TMI ) during 10 cycles. Also, as shown in FIG. 7, the first thin film also has, in cycles after the fiftieth cycle, the change rate of R1 / R2 (V R1 / R2 ) during the above-described 10 cycles, the change (V ΔT ) in the hysteresis temperature difference (ΔT) during 10 cycles, and the change (V MI ) in the phase transition temperature (T TMI ) during 10 cycles.

[0065] (Analysis Example of Experimental Data on Uniformity of Doping in Functional Thin Film) Figure 8 shows energy dispersive X-ray analysis (EDX) data obtained using a transmission electron microscope (TEM) for a body according to an embodiment. (a) is data visualizing the mapping result for V, (b) is data visualizing the mapping result for Ti, and (c) is an EDX curve graph showing the mapping results for each component (Al, V, Ti) with intensity on the horizontal axis and the depth of the sample on the vertical axis. In the figure, depth is a scale relative to the thickness of the body, the depth0 value is close to the surface of the body, and the depth140 value is close to the bottom surface of the body. For example, in the figure, the depth range of 0 to 90 nm can correspond to the above-described functional thin film, and in the figure, the depth range of 90 to 140 nm can correspond to the above-described base substrate. As described above, the base substrate is a sapphire (Al2O3) single crystal substrate, and the functional thin film is one in which at least a part of V ions in the crystal lattice of VO2 is substituted (doped) with Ti ions.

[0066] As shown in the figure, it can be confirmed that Ti is uniformly dispersed in the functional thin film after heat treatment. The functional thin film existed as a TiO2 thin film (thickness 3 nm to 5 nm) and a VO2 thin film (thickness 200 nm to 300 nm) before heat treatment. After heat treatment, as shown in the figure, the fact that Ti is uniformly distributed in the depth range of 0 to 90 nm ultimately means that Ti is uniformly dispersed in the functional thin film. This indicates that Ti has diffused through the entire functional thin film in the thickness direction and reached the surface, representing the uniformity of doping according to an embodiment. That is, as shown in the figure, the EDX curve of Ti is maintained substantially constant in the depth range of 0 to 90 nm, and this value shows a more distinct difference compared to the value in the EDX curve of Al in the figure.

[0067] Hereinafter, the uniformity of doping in the functional thin film will be described in more detail. Subsequently, as shown in FIG. 8, it can be seen that V and Ti have similar distribution levels (standard deviations). This more clearly shows the uniformity of doping. That is, it shows that Ti is distributed as uniformly as V within the VO2 thin film. This indicates that after the post-annealing process according to one embodiment, the boundary between the sacrificial layer and the main oxide layer has disappeared. This will be described later with reference to FIGS. 9 to 10.

[0068] FIG. 9 shows an enlarged view of only the mapping result for Ti among the EDX curves in FIG. 8. The average (about 2647) and standard deviation (about 567) were obtained in the range of 0 to 90 nm. And FIG. 10 shows an enlarged view of only the mapping result for V among the EDX curves in FIG. 8. The average (about 36487) and standard deviation (about 778) were obtained in the range of 0 to 90 nm. At this time, by making the y-axis arbitrary (arb.), although the intensity itself has no meaning, it can be noted that the standard deviation for Ti and the standard deviation for V can be compared. That is, it is necessary to note whether comparative materials are presented regarding whether Ti is distributed as uniformly as V within the functional thin film.

[0069] As shown in the figure, Ti corresponding to a different metal element and V of VO2 constituting the main oxide layer may have similar distribution levels to each other. That is, Ti may be distributed as uniformly as V within the functional thin film. For example, the distribution level of Ti corresponding to the different metal element may have a difference within 30% with respect to the distribution level of V of VO2 constituting the main oxide layer. More specifically, since the value obtained by dividing the difference between the two standard deviations (211) by the EDX of V (778) is 0.271, it can have a difference within 27.1%. At this time, for the convenience of calculation, the decimal part was appropriately processed by rounding up, rounding down, etc., but for more accurate calculation, up to the decimal point can be considered. In the above, the results of TEM-EDX were described from the viewpoint of the distribution level of intensity. However, when the intensity is converted to the average concentration, it is also possible to approach from the viewpoint of the distribution level of the average concentration instead of the intensity.

[0070] (Analysis Example of Experimental Data on High Crystallinity in Functional Thin Films) FIG. 11 is a diagram showing XRD (X-ray diffraction) data of a body according to an embodiment. XRD shows the crystallinity of the entire thin film. As shown in the figure, for VO2 grown on TiO2, only one main VO2 peak appears after heat treatment (see the part indicated by the arrow in the figure). That is, the main XRD peak of VO2 does not appear in the range of 2θ = 20 to 60°, and appears only in the range of 2θ = 60 to 70 °C. This indicates that VO2 is an epitaxial thin film with high crystallinity. On the contrary, when VO2 grows alone, multiple main peaks appear, indicating that it is a polycrystal thin film.

[0071] More specifically, VO2 grown on TiO2 has one peak (A) that appears in the range of 2θ = 64.92 ± 0.5 °C in the X-ray diffraction pattern measured by XRD, while VO2 grown alone without TiO2 has peaks in the ranges of 2θ = 27.84 ± 0.5 °C, 2θ = 33.4 ± 0.5 °C, 2θ = 37.08 ± 0.5 °C, 2θ = 42.26 ± 0.5 °C, 2θ = 49.52 ± 0.5 °C, 2θ = 55.54 ± 0.5 °, 2θ = 57.64 ± 0.5 °C, and 2θ = 64.94 ± 0.5 °C, respectively, for a total of eight peaks (each peak is named a1, b1, c1, D1, e1, f1, g1, h1 in order). The single peak A means an epitaxial thin film, and the multiple peaks a1, b1, c1, d1, e1, f1, g1, h1 mean a polycrystal thin film. At this time, the peak A may have a full width at half maximum FWHM of 1.0° or less. Preferably, it may be 0.79 °C or less. This supports the high crystallinity in the functional thin film according to an embodiment.

[0072] On the other hand, since even fine peaks appear in the XRD data, in the present invention, the main term "VO2 peak" targets only peaks having a certain intensity or more. For example, on the drawing, peaks not exceeding 10% of the maximum peak intensity are not considered. That is, when the intensity of peak A is 632.68, peaks having an intensity of 63.27 or less can be excluded from consideration. In the above, the embodiment in which eight peaks appear has been mainly described. However, the present invention is not necessarily limited thereto, and embodiments having less than eight or more than eight, as long as they are numbers indicating that the film is a polycrystalline thin film, are also possible. It should be noted that in the case of an epitaxial thin film, there is one main peak, while in the case of a polycrystalline thin film, a plurality of main peaks appear.

[0073] Such a functional thin film shows that through the post-annealing process, the main oxide layer is crystallized with high orientation under the influence of the crystal structure of the sacrificial layer, and the metal ions of the sacrificial layer are doped into the entire main oxide layer through self-diffusion, but the crystal structure of the main oxide layer is maintained in its original state even after doping. That is, even though it is doping with a different metal element, the crystal structure of the main oxide can be maintained. As described above, it can be seen that after the post-annealing process, the boundary between the sacrificial layer and the main oxide layer disappears, the crystal structure of the main oxide layer is maintained before and after doping, and a highly crystalline thin film in which the sacrificial layer metal ions are doped can be formed as the entire functional thin film.

[0074] Although the present invention has been described as above, those having ordinary knowledge in the relevant technical field can variously modify and change the present invention by adding, changing, or deleting components within the scope not departing from the idea of the present invention described in the claims, and this can also be said to be included in the scope of rights of the present invention.

Explanation of Reference Numerals

[0075] CP Conductive particles R Base resin 1 First direction 2 The second direction 3 The third direction 100 Body, thin film substrate 100, Body 101 The first surface 102 The second surface 103 The third surface 104 The fourth surface 105 The fifth surface 106 The sixth surface 110 Base substrate 120 Functional thin film 200, 300 External electrodes 210, 310 Conductive resin layers 220, 320 Metal layers 221, 321 The first plating layer 222, 322 The second plating layer 300 The second external electrode 310 The second conductive resin layer 320 The second metal layer 1000 Energy-sensitive electronic component

Claims

1. A single-crystalline substrate, a main oxide layer laminated on the single-crystalline substrate and doped with a different metal element, and an oxide thin film characterized in that, by energy-dispersive X-ray analysis (EDX) using a transmission electron microscope (TEM), the different metal element and the metal element of the metal oxide constituting the main oxide layer are uniformly distributed.

2. The oxide thin film according to claim 1, characterized in that the EDX curve distribution level of the different metal element has a difference within 30% with respect to the EDX curve distribution level of the metal element of the metal oxide constituting the main oxide layer.

3. The oxide thin film according to claim 1, characterized in that the standard deviation of the EDX curve of the different metal element measured in the thickness direction of the main oxide layer has a difference within 30% with respect to the standard deviation of the EDX curve of the metal element of the metal oxide constituting the main oxide layer.

4. The oxide thin film according to claim 1, characterized in that the main oxide layer is formed by integrating a crystal sacrificial layer of the different metal element and a preliminary oxide thin film formed on the crystal sacrificial layer through a post-heat treatment process.

5. The oxide thin film according to claim 4, characterized in that the crystal sacrificial layer grows on the single-crystalline substrate along the crystal direction of the single-crystalline substrate.

6. The oxide thin film according to claim 5, characterized in that the preliminary oxide thin film is a film amorphous on the crystal sacrificial layer.

7. The oxide thin film according to claim 6, characterized in that the main oxide layer is formed by crystallizing the amorphous preliminary oxide thin film along a predetermined direction along the crystal direction of the crystal sacrificial layer through the post-heat treatment process.

8. The single crystal substrate is a sapphire (Al ２ O ３ ) single crystal substrate, The main oxide layer is VO ２ The oxide thin film according to claim 1, wherein at least a part of V ions in the crystal lattice of ２ is substituted (doped) with Ti ions.

9. A single-crystalline substrate, Stacked on the single crystal substrate and including a VO layer doped with Ti ２ layer, The VO ２ VO of the layer ２ An oxide thin film characterized in that an XRD peak does not appear in the range of 2θ = 20 to 60°, and appears only in the range of 2θ = 60 to 70°C.

10. The VO ２ layer is The main VO that satisfies a certain intensity or higher ２ The oxide thin film according to claim 9, wherein the XRD peak appears only once, rather than a polycrystalline thin film in which a plurality of peaks appear in the range of 2θ = 20 to 70°, and is defined as a highly crystalline epitaxial thin film

11. The polycrystalline thin film is, The main VO ２ wherein the XRD peaks appear in two or more of the ranges of 2θ = 27.84 ± 0.5°, 2θ = 33.4 ± 0.5°, 2θ = 37.08 ± 0.5°, 2θ = 42.26 ± 0.5°, 2θ = 49.52 ± 0.5°, 2θ = 55.54 ± 0.5°, 2θ = 57.64 ± 0.5°, and 2θ = 64.94 ± 0.5° The epitaxial thin film is, The main VO ２ The oxide thin film according to claim 10, characterized in that the XRD peak appears only in the range of θ = 64.92 ± 0.5 °C.

12. The VO mentioned above ２ The main VO of the layer ２ The oxide thin film according to claim 9, wherein the half-value width HWHM of the XRD peak is 1° or less.

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