KR102028530B1 - Thermal conductive properties measurement kit for thin film - Google Patents

Abstract

Disclosed is a thermoelectric measurement kit for a thin film. In the thermoelectric characteristic measurement kit of a thin film according to an embodiment of the present invention, a substrate including an insulating layer and a first electrode pattern are formed on an upper surface of the substrate to measure thermal conductivity in a cross-plane direction of the thin film to be measured. A first measurement unit disposed on the upper surface of the substrate and spaced apart from the first measurement unit in a horizontal distance by a predetermined distance, and a second electrode pattern is formed to measure thermal conductivity in an in-plane direction of the thin film to be measured; The measurement unit may be disposed on the upper surface of the substrate to be spaced apart from the second measurement unit by a predetermined distance in a horizontal direction, and a third electrode pattern may be formed to measure the Seebeck coefficient or electrical conductivity of the thin film to be measured.

Description

Thermoelectric properties measurement kit for thin film

The present invention relates to a thermoelectric property measurement kit of a thin film, and more particularly, to a thermoelectric property measurement kit of a thin film capable of simultaneously measuring the thermoelectric properties in the vertical (cross-plane) and horizontal (in-plane) directions.

Thermoelectric phenomena refers to the reversible and direct energy conversion of heat and electricity, and is caused by the movement of electrons and holes in the material. Such thermoelectric phenomena can be broadly classified into thermoelectric cooling for converting electrical energy into thermal energy and thermoelectric generation for converting thermal energy into electrical energy.

Thermoelectric cooling uses the Peltier effect, which specifically uses endothermic and exothermic phenomena generated at both ends of the material by the flow of applied current, and is applied to thermoelectric cooling devices / modules. (Seebeck effect), which uses electromotive force generated when a temperature difference is formed across thermoelectric semiconductor elements, and is applied to electric energy production.

Thermoelectric devices using thermoelectric effects have the advantage that they can be applied immediately when high-efficiency materials are developed, but they have a disadvantage of low energy conversion efficiency during thermoelectric power generation and cooling because of low figure of merit (Z or ZT).

The thermoelectric performance is determined by electromotive force, thermal conductivity and electrical conductivity according to the temperature difference, and the performance index Z may be expressed as α ² · σ / K. Where α is the Seebeck coefficient (V / K), σ is the electrical conductivity (Ωm), K is the thermal conductivity (W / mK), and T is the absolute temperature (K). The higher the Seebeck coefficient and the higher the electrical conductivity and the lower the thermal conductivity, the higher the performance index of the thermoelectric semiconductor may be, thereby improving the energy conversion efficiency due to the thermoelectric phenomenon.

Generally, Pb-Te-based materials used in the high-temperature region and Bi-Te-based materials used in the low-temperature region have been mainly studied, but the problem of efficiency of thermoelectric performance change has not been completely solved. In addition to the development of materials, research is underway to achieve efficiency gains other than materials.

According to the existing research, if the growth of the thermoelectric material itself is a low dimension to improve the thermoelectric efficiency, a high Seebeck coefficient and a high electric conductivity can be obtained at the same time. It has been.

This is the slope of the density of electrons with respect to energy as the material constant that determines the Seebeck coefficient, which is higher than that of bulk three-dimensional materials. The result is based on the theory.

On the other hand, in the past, in order to measure the thermoelectric properties of the thermoelectric material, the thermoelectric properties were measured for a sample having a bulk form of 100 μm or more.

However, in the method of measuring the physical properties of bulk materials, the measurement of low dimensional thin film type materials is possible by the general method, but the thermal conductivity uses a method of observing the difference in thermal conductivity between the substrate and the grown thin film through a laser. There is a disadvantage that it is difficult to measure in the situation of the measurement environment temperature, such as low temperature or high temperature. In other words, with the development of thin film technology of semiconductor materials, it is difficult to measure the properties of thin film materials using the existing bulk material measurement method.As the thickness of the thin film becomes thinner (below 300 nm), the reliability of material properties can be measured. There is a problem that is difficult to secure.

Therefore, a thermoelectric characteristic measuring system suitable for the low dimensional structure is needed due to the low dimensional structure different from the bulk shape, which is a general system for measuring the characteristics of the existing thin film, and the cross-plane and in-plane inside the thin film in detail. There is a need for a system that can demonstrate differences in physical properties.

In this regard, there is a Korean Patent No. 10-1682998 entitled "Method for Measuring Thickness Directional Thermal Conductivity of Nano Thin Films".

The technical problem to be solved by the present invention is to provide a thermoelectric characteristic measurement kit of a thin film that can simultaneously measure the thermal conductivity, Seebeck coefficient, and electrical conductivity in the cross-plane and horizontal (In-plane) direction of the thin film. .

The technical problems of the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the following description.

According to an aspect of the present disclosure, a thermoelectric characteristic measurement kit for a thin film according to an embodiment of the present invention includes a substrate including an insulating layer and a first electrode pattern formed on an upper surface of the substrate, such that A first measuring unit for measuring the thermal conductivity in the plane direction, a horizontal distance spaced from the first measuring unit in the horizontal direction on the upper surface of the substrate, a second electrode pattern is formed in the in-plane direction of the thin film to be measured A second measuring unit for measuring the thermal conductivity, a horizontal distance away from the second measuring unit in the horizontal direction on the upper surface of the substrate, a third electrode pattern is formed to measure the Seebeck coefficient or electrical conductivity of the thin film to be measured And a third measuring unit.

Preferably, the first electrode pattern may include a first electrode pad receiving a current having an angular frequency w, a second electrode pad disposed on the other side of the first electrode pad, and receiving a current; width), a first heater connecting the first electrode pad and the second electrode pad, a third electrode pad receiving a voltage based on the angular frequency and a current, and spaced apart from the third electrode pad by a predetermined distance, A fourth electrode pad receiving a voltage, a first sensor connecting the first heater and the third electrode pad, and a second sensor connecting the first heater and the fourth electrode pad, wherein the first heater The width of is greater than or equal to the thickness of the thin film to be measured, and the first heater, the first and second sensors may be configured in one wiring pattern, and the thin film to be measured may be disposed on an upper surface thereof.

Preferably, the second electrode pattern may include a fifth electrode pad receiving current having an angular frequency w, a sixth electrode pad disposed on the other side of the fifth electrode pad, and receiving a current, and having a predetermined width ( a second heater connecting the fifth electrode pad and the sixth electrode pad, a seventh electrode pad receiving a voltage based on the angular frequency and a current, and a predetermined distance from the seventh electrode pad, An eighth electrode pad receiving a voltage, a third sensor connecting the second heater and the fifth electrode pad, and a fourth sensor connecting the second heater and the sixth electrode pad, wherein the second heater The width of is equal to or less than the thickness of the thin film to be measured, and the second heater, the third and fourth sensors may be configured in one wiring pattern, and the thin film to be measured may be disposed on an upper surface thereof.

Preferably, the third electrode pattern, the first coil heater for providing a heat source, the second coil heater disposed on the other side of the first coil heater, the heat is provided, a predetermined distance spaced from the first coil heater And a ninth electrode pad receiving a current, spaced apart from the ninth electrode pad, a predetermined distance spaced from the eleventh electrode pad receiving a voltage based on the current, and a predetermined distance from the eleventh electrode pad. Fifth sensors to fifth electrodes disposed between the twelfth electrode pads to be applied, the twelfth electrode pads, and the second coil heater to connect the tenth electrode pads to which a current is applied, and the ninth electrode pads to the twelfth electrode pads, respectively. Including an eight sensors, the measurement target thin film may be disposed on the upper surface of the fifth to eighth sensors.

Preferably, the first temperature of the first coil heater and the second temperature of the second coil heater are measured to measure a temperature difference between the first temperature and the second temperature, and between the eleventh electrode pad and the twelfth electrode pad. By measuring the potential difference, the electrical conductivity or the Seebeck coefficient of the measurement target thin film may be measured.

According to the present invention, thermoelectric properties (eg, thermal conductivity, Seebeck coefficient, electrical conductivity, etc.) in the cross-plane and in-plane directions of the thin film can be simultaneously measured. Furthermore, the thermoelectric property measurement kit of the present invention can be used for physical property measurement of materials that are difficult to characterize, such as polymer series, in addition to thin films of general semiconductor materials.

In addition, thermoelectric / physical properties of thin films grown in a superlattice structure can measure thermoelectric properties of thin films of 200 nm or less and can measure thermoelectric properties of materials that are difficult to find at room temperature and high temperature, depending on the temperature measurement. Can be.

Effects of the present invention are not limited to the above-mentioned effects, and other effects not mentioned will be clearly understood by those skilled in the art from the following description.

1 is a view for explaining an apparatus for measuring the thermoelectric properties of a thin film according to an embodiment of the present invention.
2 is a view for explaining a measurement target thin film according to an embodiment of the present invention.
3 is a cross-sectional view of a thermoelectric measurement kit according to an embodiment of the present invention.
4 is a view for explaining the first to the third measuring unit of the thermoelectric characteristic measurement kit according to an embodiment of the present invention.
5 is a view for explaining the width of the heater according to the thermal conductivity measurement in the vertical (cross-plane) or horizontal (in-plane) direction according to an embodiment of the present invention.
6 is a view for explaining a method for measuring the thermoelectric properties of a thin film using the thermoelectric properties measurement kit according to an embodiment of the present invention.
FIG. 7 is a diagram for describing a method of measuring a thermal conductivity of a thin film by using a 3ω method according to an embodiment of the present invention.
8 is a view for explaining a method for measuring Seebeck coefficient and electrical conductivity using a third measuring unit according to an embodiment of the present invention.

As the invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. In describing the drawings, similar reference numerals are used for similar elements.

Terms such as first, second, A, and B 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 the second component, and similarly, the second component may also be referred to as the first component. The term and / or includes a combination of a plurality of related items or any item of a plurality of related items.

When a component is referred to as being "connected" or "connected" to another component, it may be directly connected to or connected to that other component, but it may be understood that other components may be present in between. Should be. On the other hand, when a component is said to be "directly connected" or "directly connected" to another component, it should be understood that there is no other component in between.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

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. Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art, and shall not be construed in ideal or excessively formal meanings unless expressly defined in this application. Do not.

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

1 is a view for explaining an apparatus for measuring the thermoelectric properties of a thin film according to an embodiment of the present invention, Figure 2 is a view for explaining a thin film to be measured according to an embodiment of the present invention.

In the apparatus for measuring the thermoelectric properties of the thin film according to an embodiment of the present invention, the interior is blocked by the chamber 10 as shown in Figure 1 (a) to the outside, the inside of the chamber as the measurement target thin film (b) A thermoelectric characteristic measurement kit 100 capable of measuring a thermoelectric characteristic is provided. Here, the thermoelectric properties of the thin film are factors for improving the performance index of the thin film, Seebeck coefficient α (V / K), electrical conductivity σ (Ωm), thermal conductivity K (W / mK), and absolute temperature. (T) (K) and the like.

The chamber 10 may be formed in a structure having an inner space portion, and may be formed in an airtight structure so that the inner space portion may be completely shielded from the outside. Through such a configuration, it is possible to secure the vacuum degree of the inner space portion to 10 ^-5 Torr or less.

Although not shown in the figure, a turbopump (not shown) may be installed in the chamber 10 to intake and exhaust air so as to maintain a degree of vacuum in the inner space of the chamber 10. If the chamber 10 is maintained in a vacuum state, it is possible to create a precise temperature control and measurement environment by removing the convection effect. That is, the natural convection effect is caused by the buoyancy, which is the combined force of the volumetric forces in the atmospheric system with a density gradient, and in general, the natural convection effect is drastically reduced at a pressure of 10 ⁻³ to 10 ² Torr. In addition, because of pressure conditions of 10 ^-6 Torr or lower it is difficult to develop equipment to a surge in the measuring equipment produced during degassing (outgassing) element, the degree of vacuum in the chamber 100 according to this embodiment is 10 ^-4 to 10 ^- It can be formed in ⁶ Torr pressure conditions.

The chamber is provided with a thermoelectric characteristic measurement kit 100 capable of measuring thermal conductivity, Seebeck coefficient, and electrical conductivity of a thin film to be measured. The thermoelectric measurement kit 100 includes a first measuring unit measuring thermal conductivity in a cross-plane direction with respect to a thin film to be measured on a substrate, a second measuring unit measuring electrical conductivity in an in-plane direction, electrical conductivity, and Seebeck. And a third measuring unit for measuring the coefficient. In this case, the substrate may be a substrate provided with an insulating layer, that is, the substrate may be, for example, an si substrate, and an insulator layer is formed on the substrate. In this case, the insulator layer may be, for example, a SiO ₂ layer. By using an insulator material on the substrate, it is possible to allow the heat of the heater to flow along the thin film without flowing to the bottom at the time of electrical conductivity and thermal conductivity measurement.

The first measuring unit has a first electrode pattern formed on the upper surface of the substrate, and measures the thermal conductivity in the cross-plane direction of the thin film to be measured. In this case, the first measurement unit may measure the thermal conductivity in the cross-plane direction using the 3ω method. Accordingly, the first electrode pattern may form a 4-point probe electrode, and the four electrode pads may be appropriately sized (eg, ˜2 mm × ˜2 mm) to facilitate connection with the thin film to be measured. In the case of the metal heating wire positioned at the center of the pad, the width thereof may be greater than or equal to the thickness of the thin film to be measured (eg, ~ 10 μm).

The second measuring unit is disposed to be spaced apart from the first measuring unit by a predetermined distance, and a second electrode pattern is formed on the upper surface of the substrate to measure thermal conductivity in the in-plane direction of the thin film to be measured. In this case, the second measurement unit may measure the thermal conductivity in the in-plane direction by using a 3ω method. Accordingly, the second electrode pattern may form a 4-point probe electrode, and the four electrode pads may be appropriately sized (eg, ˜2 mm × ˜2 mm) to facilitate connection with the thin film to be measured, and the electrode In the case of the metal heating wire positioned at the center of the pad, the width thereof may be less than the thickness of the thin film to be measured (eg, ˜50 nm).

The third measuring unit is disposed to be spaced apart from the second measuring unit by a predetermined distance, and a third electrode pattern is formed on the upper surface of the substrate to measure the Seebeck coefficient and the electrical conductivity of the thin film to be measured.

In order to measure the thermoelectric properties of the thin film to be measured using the thermoelectric property measurement kit 100 configured as described above, the thermoelectric property measurement kit 100 is first placed on the pedestal 20. In this case, the thermoelectric measurement kit 100 may include a photoresist layer (or film layer) and a measurement area. Therefore, after depositing the measurement target thin film in the thermoelectric measurement kit 100, the photoresist layer (or film layer) is removed. As a result, the measurement target thin film is deposited only in the measurement region, and the thermoelectricity of the measurement target thin film can be measured. For example, when measuring the thermal conductivity of the thin film to be measured, it is possible to measure by depositing the thin film to be measured on the thermoelectric measurement kit 100 as shown in (c).

This thermoelectric measurement kit will be described with reference to FIG. 3.

The thin film to be measured may be a superlattice in which Al ₂ O _{3 and} ZnO are stacked as shown in (d). Specifically, the measurement target thin film may be an AO / ZnO super lattice thin film in which at least one or more AO layers and at least one ZnO layer are alternately stacked in a thickness direction as illustrated in FIG. 2. That is, the measurement target thin film may have a form in which Al ₂ O _{3 and} ZnO are alternately stacked in the thickness direction. AO / ZnO super lattice can be deposited on Si substrates using atomic layer deposition (ALD) in a handmade reactor using diethylzinc (DEZ), trimethylaluminum (TMA) and H ₂ O at 250 ° C. N2 gas can be used as the carrier gas and purge gas at a pressure of 200 mTorr and a flow rate of 50 sccm.

Since the thermoelectric characteristic measuring apparatus measures the thermoelectric characteristics of the thin film in the low temperature chamber, physical properties may be measured at a temperature of 10K or 80K to a high temperature of 500K depending on a refrigerant such as helium gas or liquefied nitrogen.

3 is a cross-sectional view of a thermoelectric characteristic measurement kit according to an embodiment of the present invention, Figure 4 is a view for explaining the first to third measurement unit of the thermoelectric characteristic measurement kit according to an embodiment of the present invention, Figure 5 6 is a view illustrating a width of a heater according to thermal conductivity measurement in a cross-plane direction or an in-plane direction according to an embodiment of the present invention, and FIG. 6 is a thermoelectric characteristic according to an embodiment of the present invention. It is a figure for demonstrating the method for measuring the thermoelectric property of a thin film using a measurement kit.

3 and 4, the thermoelectric characteristic measurement kit 100 of a thin film according to an exemplary embodiment of the present invention may include a substrate 110, a first measurement unit 120, a second measurement unit 130, and a third measurement. It includes a unit 140, the first to third measuring units 120, 130, 140 are disposed spaced apart a predetermined distance in the horizontal direction on the substrate.

The substrate 110 may be a substrate having an insulating layer 114, that is, the substrate 110 may be, for example, an si substrate 112, and an insulator layer 114 is formed on the substrate. In this case, the insulator layer 114 may be, for example, an SiO ₂ layer. By using an insulator material on the substrate, it is possible to allow the heat of the heater to flow along the thin film without flowing to the bottom at the time of electrical conductivity and thermal conductivity measurement.

The first measuring unit 120 has a first electrode pattern formed on the upper surface of the substrate, and measures the thermal conductivity in the cross-plane direction of the thin film to be measured. In this case, the first measurement unit 120 may measure the thermal conductivity in the cross-plane direction by using the 3ω method. Thus, the first electrode pattern may form a 4-point probe electrode.

The first electrode pattern 120 includes a first electrode pad 121, a second electrode pad 122, a first heater 123, a third electrode pad 124, a fourth electrode pad 125, and a first sensor. 126, and a second sensor 127, which may be configured in one wiring pattern.

The first electrode pad 121 receives an alternating current having an angular frequency (w), and may be formed of a conductive metal material such as platinum. In this case, the first electrode pad 121 may be provided in a rectangular or normal shape.

The second electrode pad 122 is disposed on the other side of the first electrode pad 121 and receives a current, and may be formed of a conductive metal material such as platinum. In this case, the second electrode pad 122 may be provided in a rectangular or normal shape.

One end of the first heater 123 is connected to the first electrode pad 121, and the other end thereof is connected to the second electrode pad 122, and may include a wiring member having a width of a predetermined width. In this case, the width of the first heater 123 may be greater than or equal to the thickness d of the measurement target thin film.

The third electrode pad 124 receives a voltage based on an angular frequency and a current, and may be formed of a conductive metal material such as platinum. In this case, the third electrode pad 124 may be provided in a rectangular or normal shape.

The fourth electrode pad 125 is spaced apart from the third electrode pad 124 by a predetermined distance and receives a voltage.

The first sensor 126 connects the first heater 123 and the third electrode pad 124, and the second sensor 127 connects the first heater 123 and the fourth electrode pad 125. The thin film to be measured may be disposed on upper surfaces of the first heater 123, the first sensor 126, and the second sensor 127, through which the voltage of the thin film to be measured may be detected.

Meanwhile, the first to fourth electrode patterns 121, 122, 124, and 125 may have the same shape, and the first and second electrode patterns 121 and 122, the third and fourth electrode patterns 124, 125 may each be arranged to be symmetrical. In addition, the first sensor and the second sensor 126, 127 may be provided in the same shape, and may be arranged to be symmetrical. In addition, the widths of the wirings constituting the first and second sensors 126 and 127 may be configured to be the same.

In the first electrode pattern 120 having the above configuration, the sensing pattern to which the MEMS technology is applied may be formed of platinum (Pt) material.

The thermal conductivity in the vertical direction of the thin film may be measured using the first measuring unit 120 configured as described above, and a description thereof will be made with reference to FIG. 6.

The second measuring unit 130 is disposed on the upper surface of the substrate to be spaced apart from the first measuring unit 120 by a predetermined distance in a horizontal direction, and a second electrode pattern is formed to increase the thermal conductivity in the in-plane direction of the thin film to be measured. Measure In this case, the second measurement unit 130 may measure the thermal conductivity in the cross-plane direction by using the 3ω method. Thus, the second electrode pattern may form a 4-point probe electrode.

In detail, the second electrode pattern includes the fifth electrode pad 131, the sixth electrode pad 132, the second heater 133, the seventh electrode pad 134, the eighth electrode pad 135, and the third sensor ( 136 and a fourth sensor 137, which may be configured in one wiring pattern.

The fifth electrode pad 131 receives an alternating current having an angular frequency w, and may be formed of a conductive metal material such as platinum. In this case, the fifth electrode pad 131 may be provided in a rectangular or normal shape.

The sixth electrode pad 132 is disposed on the other side of the fifth electrode pad 131 and receives a current, and may be formed of a conductive metal material such as platinum. In this case, the sixth electrode pad 132 may be provided in a rectangular or normal shape.

One end of the second heater 133 is connected to the fifth electrode pad 131, and the other end thereof is connected to the sixth electrode pad 132, and may include a wiring member having a width of a predetermined width. In this case, the width of the second heater 133 may be less than the thickness d of the measurement target thin film.

The seventh electrode pad 134 receives a voltage based on an angular frequency and a current, and may be formed of a conductive metal material such as platinum. In this case, the seventh electrode pad 134 may be provided in a rectangular or normal shape.

The eighth electrode pad 135 is disposed spaced apart from the seventh electrode pad 134 by a predetermined distance and receives a voltage.

The third sensor 136 connects the second heater 133 and the seventh electrode pad 134, and the fourth sensor 137 connects the second heater 133 and the eighth electrode pad 135. The measurement target thin film may be disposed on the upper surfaces of the second heater 133, the third sensor, and the fourth sensor 136 and 137, and thus the voltage of the measurement target thin film may be detected.

Meanwhile, the fifth to eighth electrode pads 131, 132, 134, and 135 may be provided in the same shape, and the fifth and sixth electrode pads 131, 132, the seventh and eighth electrode pads 134, 135 may be arranged to be symmetrical to each other. In addition, the third sensor and the fourth sensor 136, 137 may be provided in the same shape, and may be arranged to be symmetrical. In addition, the widths of the wirings constituting the third and fourth sensors 136 and 137 may be configured to be the same.

In the second electrode pattern having the above configuration, the sensing pattern to which the MEMS technology is applied may be formed of platinum (Pt) material.

The thermal conductivity of the in-plane of the thin film may be measured using the second measuring unit 130 configured as described above, and a description thereof will be made with reference to FIG. 6.

On the other hand, as shown in the drawing, the first measuring unit 120 and the second measuring unit 130 have the same configuration, but the width of the heater is different. That is, the heaters have different widths according to the thermal conductivity measurement in the cross-plane direction or in-plane direction. For example, referring to FIG. 5, when measuring the thermal conductivity in the vertical direction, the width W of the first heater is greater than or equal to the thickness d of the thin film to be measured, and when measuring the thermal conductivity in the horizontal direction, the second width is measured. The width of the heater may be less than the thickness of the thin film.

The first measuring unit 120 and the second measuring unit 130 are configured to measure the thermal conductivity, and since the measuring methods are the same, a detailed description of the method of measuring the thermal conductivity will be described with reference to FIG. 6.

The third measuring unit 140 is spaced apart from the second measuring unit 130 in the horizontal direction by a predetermined distance on the upper surface of the substrate 110, the third electrode pattern is formed to determine the Seebeck coefficient or electrical conductivity of the thin film to be measured. Measure

The third electrode pattern includes the first and second coil heaters 141 and 142, the ninth electrode pad 143, the tenth electrode pad 144, the eleventh electrode pad 145, the twelfth electrode pad 146, And fifth to eighth sensors 147, 148, 149, and 150.

The first coil heater 141 may serve to apply a heat source to the measurement target thin film in order to measure the surface temperature and voltage of the measurement target thin film by contact. As illustrated, the first coil heater 141 may form a pattern in a zigzag shape and form a predetermined width.

The second coil heater 142 is disposed on the other side of the first coil heater 141 and receives heat from the first coil heater 141. That is, the second coil heater 142 receives heat transmitted from the first coil heater 141 through the ninth through twelfth electrodes 143, 144, 145, and 146. As illustrated, the second coil heater 142 may form a pattern in a zigzag shape, and may form a predetermined width.

The first and second coil heaters 141 and 142 may operate as a heater and a temperature sensor, detect a temperature difference ΔT, and be made of a material having a uniform resistance change according to temperature such as platinum (Pt). have. In addition, the first and second coil heaters 141 and 142 may have a height of several hundred nm to several um or more on a substrate, unlike other electrodes.

The ninth through twelfth electrode pads 143, 144, 145, and 146 are in the form of 4 probes, and are disposed between the first coil heater 141 and the second coil heater 142 and have currents at both sides (the ninth electrode pad and the tenth electrode pad). By applying, voltage can be measured from the inside (eleventh electrode pad, twelfth electrode pad), and the electrical conductivity and the Seebeck coefficient can be measured by the voltage measurement.

Specifically, the ninth electrode pads and the tenth electrode pads 143 and 144 may be provided in a rectangular shape having a predetermined area and a current may be applied. In this case, areas of the ninth electrode pads and the tenth electrode pads 143 and 144 may be configured to be the same.

The eleventh and twelfth electrode pads 145 and 146 may be provided in a rectangular shape having a predetermined area and receive a voltage based on a current applied through the ninth and tenth electrode pads 143 and 144. In this case, areas of the eleventh electrode pad and the twelfth electrode pad 145 and 146 may be configured to be the same.

The fifth sensor 147 connects the ninth electrode pad 143, the sixth sensor 148 connects the tenth electrode pad 144, and the seventh sensor 149 is the eleventh electrode pad 145. The eighth sensor 150 connects the twelfth electrode pad 150. The measurement target thin film may be disposed on the upper surfaces of the fifth to eighth sensors 147, 148, 149, and 150, and the voltage of the measurement target thin film may be sensed through this.

Although not shown in the drawings, a heat sink may be further provided to prevent temperature rise. The heat sink is disposed adjacent to the second coil heater and prevents the temperature rise. That is, the heat sink simultaneously performs the role of electrical connection and heat dissipation, and may be made of copper (Cu) with little heat leakage through the substrate.

A method of measuring Seebeck coefficient and electrical conductivity using the third measuring unit 140 having such a configuration will be described with reference to FIG. 8.

Using the thermoelectric characteristic measurement kit configured as described above, it is possible to simultaneously measure the thermal conductivity in the cross-plane direction, the thermal conductivity in the in-plane direction, the electrical conductivity and the Seebeck coefficient of the thin film to be measured.

In order to measure the thermoelectric characteristics of the thin film to be measured using the thermoelectric characteristic measurement kit, first, thermoelectric characteristics measurement in which a first electrode pattern, a second electrode pattern, and a third electrode pattern are formed on a substrate as shown in FIG. A photoresist layer or film layer (A) is deposited as shown in (b) using a photolithography process or film on top of the kit. Then, in (b), only the pattern (B) of the measurement position is exposed using etching or the like. Then, the thermoelectric characteristic measurement kit is composed of a photoresist layer (or film layer) (A) and the measurement region (B) as shown in (c), the thermoelectric characteristics of the thin film using the thermoelectric characteristic measurement kit formed as shown in (c) Can be measured. Specifically, after depositing the measurement target thin film (C) on the thermoelectric characteristic measurement kit of (c) (d), the photoresist layer (or film layer) (A) is removed. Then, the measurement target thin film is deposited only in the measurement region as shown in (e), and the thermoelectricity of the measurement target thin film can be measured.

FIG. 7 is a diagram for describing a method of measuring a thermal conductivity of a thin film by using a 3ω method according to an embodiment of the present invention.

Referring to FIG. 7, a current is applied from a source meter to a first electrode pad, and at the same time, a frequency (ω) is transmitted to a first electrode pad and a measurement device as reference values. Then, the third and fourth electrode pads measure the voltage based on the reference frequency. In the connection A, the V _{ω + 3ω} value is measured, and in the connection B, the V _ω value is measured. V _{3 ω} is so because of the low signal value AB for independently because measurement is difficult, significantly remove only the value of V _ω and then a solution determined by only V _ω value from the value that has a value greater than V _{3 ω} Find V _{3 ω} through mode.

에 선형적으로 비례하여 발생하는 것으로부터 설정되어진다. 또한 가해주는 전류가 증가함에 따라 전압과 주파수가 선형적으로 비례하는 영역의 주파수 크기 또한 증가하게 되므로 주파수 영역을 고려하여 측정을 진행한다. Specifically, a current is applied to the first electrode pad and a voltage signal corresponding to the measurement frequency is measured at the third and fourth electrode pads. At this time, the measurement is performed in the section where V _{3 ω} and lnf are linearly inversely proportional. This is due to the applied current

It is set from what occurs linearly in proportion to. In addition, as the applied current increases, the frequency magnitude of the region where voltage and frequency are linearly proportional also increases, so the measurement is performed considering the frequency domain.

Hereinafter, the process of measuring the thermal conductivity will be described by using an equation.

First, an alternating current I as shown in Equation 1 below is applied to the first electrode pad.

[Equation 1]

Joule heat generated by the applied current is generated, and the metal electrode generates heat through the joule heat, and the heat through the heat source has a 2ω component to heat the thin film to be measured. At this time, the generated string P is represented by Equation 2 described below.

[Equation 2]

Therefore, the temperature change of the surface according to the heat source also has a 2ω component. That is, the surface temperature T according to the heat source is expressed by Equation 3 described below.

[Equation 3]

In the case of metal, since the electrical resistance increases linearly with temperature, the electrical resistance also has a 2ω component. Therefore, the resistance R is as shown in Equation 4 described below.

[Equation 4]

The voltage drop across the metal wires (third and fourth electrode pads) generated by Joule's heat is equal to Equation 5 described below, and through this voltage drop, 3ω frequency components as shown in Equation 6 can be obtained in addition to the existing frequency components. . By measuring the voltage drop having the 3ω frequency component, the temperature change ΔT of the heated metal electrode can be obtained as shown in Equation (7).

[Equation 5]

[Equation 6]

[Equation 7]

The thermal conductivity k of the thin film can be measured using Equation 8 based on the temperature change of the electrode thus obtained.

[Equation 8]

On the other hand, since the thermal conductivity is measured in a low temperature chamber, the physical properties can be measured at a temperature of 10K or 80K to a high temperature of 500K depending on a refrigerant such as helium gas or liquefied nitrogen.

Here, the first measuring unit measures the thermal conductivity in the cross-plane direction. However, the second measuring unit measures the thermal conductivity in the in-plane direction. The first measuring unit measures the thermal conductivity in the cross-plane direction. Since it is the same as, the description thereof will be omitted.

8 is a view for explaining a method for measuring Seebeck coefficient and electrical conductivity using a third measuring unit according to an embodiment of the present invention.

8 (a) is a simplified illustration of the electrode pattern of the third measuring unit, (b) is a view for explaining a method of measuring Seebeck coefficient, (c) is a view for explaining a method of measuring electrical conductivity Drawing.

First, a method of measuring Seebeck coefficient will be described with reference to (b). The third measuring unit measures the first temperature T1 of the first coil heater and the second temperature T2 of the second coil heater, and uses the difference between the first temperature T1 and the second temperature T2 as a temperature difference ( ΔT), and the potential difference ΔV between the eleventh electrode pad and the twelfth electrode pad may be measured. Therefore, by continuously increasing the input heating power of the first coil heater, the difference between the temperature ΔT and the voltage ΔV may be continuously measured, and the Seebeck coefficient S may be measured according to S = ΔV / ΔT.

The horizontal Seebeck coefficient can be measured in the temperature range of 25-300 K in the cryogenic vacuum chamber.

Next, a method of measuring electrical conductivity will be described with reference to (c). The electrical conductivity σ is calculated using the resistance and the cross-sectional area of the measurement target material. The third measuring unit measures the current I humanized in the ninth electrode pad and the tenth electrode pad, and the seventh sensor and the eighth sensor. The voltage (V) of the thin film to be measured is measured using a sensor. Then, the resistance can be calculated using the measured current and voltage, and the electrical conductivity can be measured using the measured current and voltage.

On the other hand, the electrical conductivity of the thin film to be measured can be measured in a temperature range of 10-300K in a cryogenic vacuum chamber having a pressure of less than 10 ^-5 Torr.

So far I looked at the center of the preferred embodiment for the present invention. Those skilled in the art will appreciate that the present invention can be implemented in a modified form without departing from the essential features of the present invention. Therefore, the disclosed embodiments should be considered in descriptive sense only and not for purposes of limitation. The scope of the present invention is shown in the claims rather than the foregoing description, and all differences within the scope will be construed as being included in the present invention.

100: thermoelectric measurement kit
110: substrate
120: first measuring unit
130: second measuring unit
140: third measuring unit
200: thin film

Claims (5)

A substrate including an insulating layer;
A first measuring unit formed on a top surface of the substrate to measure thermal conductivity in a cross-plane direction of the thin film to be measured;
A second measuring part disposed on the upper surface of the substrate in a horizontal distance from the first measuring part in a horizontal direction, and having a second electrode pattern formed thereon to measure thermal conductivity in an in-plane direction of the thin film to be measured; And
A third measurement part disposed on the upper surface of the substrate in a horizontal distance from the second measurement part in a horizontal direction, and having a third electrode pattern formed therein to measure the Seebeck coefficient or electrical conductivity of the thin film to be measured;
The first electrode pattern,
A first electrode pad receiving a current having an angular frequency w;
A second electrode pad disposed on the other side of the first electrode pad and configured to receive a current;
A first heater having a predetermined width and connecting the first electrode pad and the second electrode pad;
A third electrode pad receiving a voltage based on the angular frequency and the current;
A fourth electrode pad spaced apart from the third electrode pad by a predetermined distance and receiving a voltage;
A first sensor connecting the first heater and the third electrode pad; And
Including a second sensor for connecting the first heater and the fourth electrode pad,
The first heater, the first and the second sensor is composed of a single wiring pattern, characterized in that the upper surface of the measurement target thin film is disposed,
The second electrode pattern,
A fifth electrode pad receiving a current having an angular frequency w;
A sixth electrode pad disposed on the other side of the fifth electrode pad and configured to receive a current;
A second heater having a predetermined width and connecting the fifth electrode pad and the sixth electrode pad;
A seventh electrode pad receiving a voltage based on the angular frequency and the current;
An eighth electrode pad spaced apart from the seventh electrode pad by a predetermined distance and receiving a voltage;
A third sensor connecting the second heater and the fifth electrode pad; And
It includes a fourth sensor for connecting the second heater and the sixth electrode pad,
The second heater, the third and the fourth sensor is composed of one wiring pattern, the upper surface of the measurement target thin film is disposed,
The width of the first heater is equal to or greater than the thickness of the thin film to be measured, and the width of the second heater is less than the thickness of the thin film to be measured. delete delete The method of claim 1,
The third electrode pattern is,
A first coil heater providing a heat source;
A second coil heater disposed on the other side of the first coil heater and receiving heat;
A ninth electrode pad disposed at a predetermined distance from the first coil heater and receiving a current;
An eleventh electrode pad disposed to be spaced apart from the ninth electrode pad by a predetermined distance and receiving a voltage based on the current;
A twelfth electrode pad disposed at a predetermined distance from the eleventh electrode pad and receiving a voltage;
A tenth electrode pad disposed between the twelfth electrode pad and the second coil heater and receiving a current;
Including the fifth to eighth sensor to connect the ninth electrode pad to the twelfth electrode pad, respectively,
The thermoelectric characteristics measurement kit of the thin film, characterized in that the measurement target thin film is disposed on the upper surface of the fifth to eighth sensors. The method of claim 4, wherein
By measuring the first temperature of the first coil heater and the second temperature of the second coil heater, by measuring the temperature difference between the first temperature and the second temperature, by measuring the potential difference between the eleventh electrode pad and the twelfth electrode pad The thermoelectric characteristics measurement kit of the thin film, characterized in that for measuring the electrical conductivity or Seebeck coefficient of the thin film to be measured.

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