JP2011018689A - Laminate structure for thermoelectric conversion, thermoelectric conversion element, infrared sensor and method for manufacturing the laminate structure for thermoelectric conversion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a laminate structure for thermoelectric conversion, capable of preventing a thermoelectric material layer from peeling from a substrate in a manufacturing step by achieving high bondability between the thermoelectric material layer and the substrate, and maintaining thermoelectric characteristics in a direction horizontal to the substrate; a thermoelectric conversion element using the laminate structure for thermoelectric conversion; an infrared sensor manufactured using the thermoelectric conversion element; and a method for manufacturing the laminate structure for thermoelectric conversion.SOLUTION: The laminate structure for thermoelectric conversion has a structure in which a substrate 10, a buffer layer 20 formed by distributingly laminating a plurality of independent laminate portions 21 comprising Ti metal or Ti alloy, and a thermoelectric material layer 30 containing as effective components one or two elements selected from a first group of Bi and Sb and one or two elements selected from a second group of Te and Se are laminated in this order.

Description

  The present invention relates to a laminated structure for thermoelectric conversion, a thermoelectric conversion element using the laminated structure for thermoelectric conversion, an infrared sensor using the thermoelectric conversion element, and a method for producing the laminated structure for thermoelectric conversion.

Infrared sensors are roughly classified into quantum types and thermal types. Among them, the quantum type is excellent in sensitivity and response speed, but is limited in application fields such as being very expensive and inferior in immediacy. On the other hand, the thermal type is classified into a bolometer type, a pyroelectric type, and a thermopile type, and although there are difficulties in sensitivity and response speed, since it is inexpensive, remarkable development has been seen in recent years. In particular, as an inexpensive consumer infrared sensor mounted on an automobile, a thermopile type that is superior in all respects except detection sensitivity is being put into practical use.
A thermopile type infrared sensor is a sensor that absorbs infrared rays and converts the infrared rays into heat, and detects this thermal energy as a thermoelectromotive force due to the Seebeck effect of the thermoelectric material. As a method for improving the detection sensitivity, it is considered effective to apply BiTe having high characteristics to the thermoelectric material for detecting the infrared intensity. However, BiTe is a very brittle material, and when used as a thin film, there is a problem that it is easily peeled off from the substrate by ultrasonic cleaning or the like during the manufacturing process.
Conventionally, there has been a technique for improving the adhesion between a substrate and a thermoelectric material using BiTe by optimizing the film forming conditions. As such a thing, there exists the following patent document 1, for example.
Patent Document 1 below is an invention relating to a thermoelectric power generation element and a method for manufacturing the same, and discloses a method for manufacturing a micro thermoelectric power generation element and wiring with a conductive adhesive, and a technique related to the structure.

JP 2001-358373 A

In the said patent document 1, there exists an advantage by which the wiring of a micro thermoelectric power generation element does not short-circuit or a pattern missing.
However, BiTe is a very brittle material, and when used as a thin film, there is a problem that it is easily peeled off from the substrate by ultrasonic cleaning or the like in the manufacturing process. There is a problem that no measures are taken against prevention of peeling from the sheet, and no such configuration is disclosed.

  Therefore, the present invention solves the above-described conventional problems and realizes high adhesion between the thermoelectric material layer and the substrate, thereby preventing the thermoelectric material layer from peeling off from the substrate in the manufacturing stage and at the same time with the substrate. Laminate structure for thermoelectric conversion capable of maintaining directional thermoelectric characteristics, thermoelectric conversion element using the laminate structure for thermoelectric conversion, infrared sensor using the thermoelectric conversion element, and method for producing the laminate structure for thermoelectric conversion The issue is to provide

  The laminated structure for thermoelectric conversion of the present invention is selected from a substrate, a buffer layer formed by dispersing and laminating a plurality of independent laminated parts made of Ti metal or Ti alloy, and a first group of Bi and Sb. A first feature is that a thermoelectric material layer containing one or two elements and one or two elements selected from the second group of Te and Se as active components is laminated in this order.

According to the first feature of the present invention, the substrate, the buffer layer formed by laminating a plurality of independent laminated parts made of Ti metal or Ti alloy, and the first group of Bi and Sb are used. Since the thermoelectric material layer containing the selected 1 or 2 element and the 1 or 2 element selected from the second group of Te and Se as active components is laminated in this order, the deformation absorption capacity against stress By forming a buffer layer on the substrate with a Ti metal layer or a Ti alloy layer having a layer and laminating a thermoelectric material layer on the buffer layer, high adhesion between the substrate and the thermoelectric material layer can be realized. Therefore, even when the thermoelectric material layer is used as a thin film, it can be made difficult to peel from the substrate in the manufacturing stage.
In addition, since the buffer layer is formed by laminating and forming a plurality of independent laminated portions made of Ti metal or Ti alloy, the insulation between the buffer layer and the thermoelectric material layer is ensured. Can be secured. Therefore, the thermoelectric characteristics in the horizontal direction with respect to the substrate can be maintained.
Furthermore, a large electromotive force is obtained by forming a thermoelectric material layer containing, as active ingredients, one or two elements selected from the first group of Bi and Sb and one or two elements selected from the second group of Te and Se. It can be a thermoelectric material layer.

  The thermoelectric conversion element of the present invention is formed by forming the thermoelectric conversion laminated structure according to the first feature with a certain length and laminating electrode layers on both ends of the thermoelectric conversion laminated structure. The second feature is that a hot junction part and a cold junction part are provided.

  According to the second feature of the present invention, the thermoelectric conversion laminated structure according to the first feature is formed with a certain length, and electrode layers are laminated on both ends of the thermoelectric conversion laminated structure. Since the hot junction portion and the cold junction portion thus formed are provided, a thermoelectric conversion element capable of realizing high adhesion between the substrate and the thermoelectric material layer can be obtained. In addition, thermoelectric characteristics in the horizontal direction with respect to the substrate can be maintained, and a thermoelectric conversion element having a large electromotive force can be obtained.

  A third feature of the infrared sensor of the present invention is that the infrared sensor includes an infrared absorption heat generating portion connected to the hot junction portion of the thermoelectric conversion element according to claim 2.

  According to the third aspect of the present invention, since the infrared absorption heat generating part connected to the hot junction part of the thermoelectric conversion element according to the second characteristic is provided, high adhesion between the substrate and the thermoelectric material layer is achieved. Infrared sensor capable of realizing the characteristics. Further, the thermoelectric characteristics in the horizontal direction with respect to the substrate can be maintained, and an infrared sensor having a large electromotive force can be obtained. Therefore, an infrared sensor having high detection sensitivity can be obtained.

  The method for manufacturing a laminated structure for thermoelectric conversion according to the present invention includes a step of laminating and forming a plurality of independent laminated portions made of Ti metal or Ti alloy on a substrate, and a buffer layer formed by dispersing each other. And laminating a thermoelectric material layer containing, as active ingredients, one or two elements selected from the first group of Bi and Sb and one or two elements selected from the second group of Te and Se. This is the fourth feature.

  According to the fourth aspect of the present invention, a step of laminating and forming a buffer layer formed by dispersing a plurality of independent laminated portions made of Ti metal or Ti alloy on the substrate, and through the buffer layer, And a step of laminating a thermoelectric material layer containing, as active ingredients, one or two elements selected from the first group of Bi and Sb and one or two elements selected from the second group of Te and Se. A buffer layer made of a Ti metal layer or a Ti alloy layer is formed on the substrate, and one or two elements selected from the first group of Bi and Sb and the second group of Te and Se are formed through the buffer layer. A thermoelectric material layer containing one or two elements selected from the above as an active ingredient can be formed. Therefore, a laminated structure for thermoelectric conversion capable of realizing high adhesion between the substrate and the thermoelectric material layer can be manufactured. Accordingly, it is possible to prevent peeling of the thermoelectric material layer from the substrate in the manufacturing stage. In addition, it is possible to manufacture a laminated structure for thermoelectric conversion that can reliably ensure insulation between the buffer layer and the thermoelectric material layer and can maintain thermoelectric characteristics in the horizontal direction with respect to the substrate. Moreover, the laminated structure for thermoelectric conversion with a large electromotive force can be manufactured.

  According to the laminated structure for thermoelectric conversion of the present invention, the thermoelectric conversion element using the laminated structure for thermoelectric conversion, the infrared sensor using the thermoelectric conversion element, and the method for producing the laminated structure for thermoelectric conversion, the thermoelectric material layer and By realizing high adhesion to the substrate, it is possible to prevent the thermoelectric material layer from being peeled off from the substrate in the manufacturing stage. In addition, the thermoelectric characteristics in the horizontal direction with respect to the substrate can be maintained, and a thermoelectric conversion laminated structure having a large electromotive force, a thermoelectric conversion element using the thermoelectric conversion laminated structure, and an infrared sensor using the thermoelectric conversion element be able to.

It is a perspective view which simplifies and shows the manufacturing process of the thermoelectric conversion element which concerns on embodiment of this invention. It is a top view which simplifies and shows the internal structure of the infrared sensor which concerns on embodiment of this invention. It is a perspective view which shows the modification of the buffer layer which comprises the thermoelectric conversion element which concerns on embodiment of this invention.

  With reference to the following drawings, a thermoelectric conversion laminated structure according to an embodiment of the present invention, a thermoelectric conversion element using the thermoelectric conversion laminated structure, an infrared sensor using the thermoelectric conversion element, and the thermoelectric conversion laminate A method of manufacturing the structure will be described to help understand the present invention. However, the following description is an embodiment of the present invention, and does not limit the contents described in the claims.

  First, with reference to FIG. 1, the manufacturing method of the thermoelectric conversion element 1 which concerns on embodiment of this invention is demonstrated.

Referring to FIG. 1A, the buffer layer 20 is formed by laminating and forming a plurality of independent laminated portions 21 made of Ti metal on a substrate 10 by sputtering.
The substrate 10 may be any substrate as long as it is used as a printed circuit board, such as a rigid substrate, a flexible substrate, or a rigid flexible substrate. For example, a paper phenol substrate, a paper epoxy substrate, a glass composite substrate, a glass epoxy substrate, a ceramic substrate, a Teflon (registered trademark) substrate, an alumina substrate, a composite substrate, a Si substrate, a SiN substrate, and the like can be used.

Moreover, the independent laminated part 21 is not restricted to what consists of Ti metal, You may consist of Ti alloy. For example, Ti-Ta or Ti-Al can be used as the Ti alloy.
In addition, the method of forming the independent laminated portion 21 is not limited to sputtering, but any other physical vapor deposition method such as PLD (Pulsed Laser Deposition) method or EB (Electron Beam) method, chemical vapor deposition method, or any other method. There may be.
The thickness of the buffer layer 20 is desirably 2 nm to 5 nm, more preferably 2 nm to 3 nm.
Here, the “thickness” of the buffer layer 20 refers to a dimension in the same direction as the thickness direction A of the substrate 10 as shown in FIG.

Further, the shape and number of the independent laminated portions 21, the arrangement position on the substrate 10, and the like are not limited to those in the present embodiment, and can be changed as appropriate. For example, the shape of the independent laminated portion 21 can be a point, an ellipse, a quadrangle, a polygon, a filament, or the like. Further, as the arrangement position on the substrate 10, the plurality of independent laminated portions 21 may be regularly arranged, or may be irregularly arranged.
That is, by forming a plurality of independent laminated portions 21 in a mutually dispersed manner, the plurality of independent laminated portions 21 can be made independent from each other, and the horizontal direction of the substrate 10 is B- in FIG. Any configuration can be used as long as no current flows in the B-line direction. More specifically, any buffer layer 20 may be used as long as it can be configured such that no current flows from a later-described hot junction portion 41 side to a cold junction portion 42 side.

Next, referring to FIG. 1B, after the buffer layer 20 is formed, the thermoelectric material layer 30 is continuously formed on the buffer layer 20 by sputtering so that the independent laminated portion 21 made of Ti metal is not oxidized. Laminate.
As the thermoelectric material layer 30, a layer containing 1 or 2 element selected from the first group of Bi and Sb and 1 or 2 element selected from the second group of Te and Se as active ingredients is used. For example, Bi-Sb-Te, Sb-Te, Sb-Se, Bi-Se, Bi-Te, Bi-Sb-Se-Te can be used. By setting it as such a structure, it can be set as the thermoelectric material layer 30 with a large electromotive force.

Moreover, the lamination | stacking method of the thermoelectric material layer 30 is not restricted to sputtering, You may use other physical vapor deposition methods, such as PLD (Pulsed Laser Deposition) method and EB (Electron Beam) method.
The thickness of the thermoelectric material layer 30 is preferably 100 nm to 500 nm, more preferably 300 nm to 400 nm.

  As shown in FIG. 1B, the thermoelectric conversion laminated structure 100 in which the thermoelectric material layer 30 is laminated on the substrate 10 via the buffer layer 20 is formed by the lamination of the thermoelectric material layer 30.

Next, with reference to FIG.1 (c), the electrode layer 40 is laminated | stacked and formed in the both ends of the laminated structure 100 for thermoelectric conversion formed with fixed length. The electrode layer 40 includes a hot junction part 41 and a cold junction part 42.
As the electrode layer 40, a highly conductive metal such as gold, platinum, aluminum, or copper can be used.
The electrode layer 40 can be formed by a physical vapor deposition method such as sputtering, a PLD (Pulsed Laser Deposition) method, or an EB (Electron Beam) method.
By passing through the above process, the thermoelectric conversion element 1 shown in FIG.1 (c) is manufactured.
This thermoelectric conversion element 1 has the following characteristics.

High adhesion between the substrate 10 and the thermoelectric material layer 30 can be realized by forming the buffer layer 20 with a Ti metal layer or a Ti alloy layer having the ability to absorb deformation against stress. Therefore, even when the thermoelectric material layer 30 is used as a thin film, it can be made difficult to peel from the substrate 10 in the manufacturing stage.
Further, by forming a plurality of independent laminated portions 21 made of Ti metal in a mutually dispersed manner to form the buffer layer 20, it is possible to prevent current from flowing between the adjacent independent laminated portions 21. That is, the buffer layer 20 having a higher resistance value than the thermoelectric material layer 30 can be obtained. Therefore, the insulation between the buffer layer 20 and the thermoelectric material layer 30 can be ensured without interposing the insulating layer between the buffer layer 20 and the thermoelectric material layer 30. Therefore, the thermoelectric characteristics in the horizontal direction with respect to the substrate 10 can be maintained.
Furthermore, by making the thermoelectric material layer 30 including, as active ingredients, one or two elements selected from the first group of Bi and Sb and one or two elements selected from the second group of Te and Se, A large thermoelectric conversion element 1 can be obtained.

Next, an infrared sensor 200 according to the present embodiment will be described with reference to FIG.
The infrared sensor 200 is a far-infrared sensor, which includes the thermoelectric conversion element 1 described above on the substrate 10 and has an infrared absorbing heat generating unit 50 connected to the hot junction 41.
The same member and the same function are given the same number, and the following description is omitted.

The infrared ray is absorbed by the infrared absorption heat generating unit 50, so that the temperature of the hot contact portion 41 connected to the infrared absorption heat generating unit 50 rises.
When the temperature of the hot junction part 41 rises, a potential difference corresponding to the temperature difference from the cold junction part 42 is generated in the thermoelectric material layer 30. That is, an electromotive force corresponding to the potential difference of the thermoelectric material layer 30 is obtained. This electromotive force is taken out from the electrodes constituting the cold junction portion 42 and sent as an electrical signal to a readout circuit on the substrate 10. This electrical signal indicates the amount of infrared rays incident on the region where the thermoelectric conversion element 1 is disposed. Based on electric signals from a number of thermoelectric conversion elements 1 (not shown) on the substrate 10, an infrared image is created by an external circuit.

  Note that the infrared absorption heat generating portion 50 can be formed of a nickel chrome film, a platinum film, or the like.

  Next, with reference to FIG. 3, the modification of the buffer layer 20 which comprises the thermoelectric conversion element 1 which concerns on embodiment of this invention is demonstrated.

  First, referring to FIG. 3A, in the first modification, the independent laminated portion constituting the buffer layer 20 is formed in a line. In other points, it is the same as the thermoelectric conversion element 1 in embodiment of this invention mentioned above. The same member and the same function are given the same number, and the following description is omitted.

  As shown in FIG. 3A, the buffer layer 20 is formed by laminating a plurality of independent laminated portions 22 each having a long line in the C-C line direction at intervals in the B-B line direction. It can be set as the structure which an electric current does not flow from the BB line direction, ie, the warm junction part 41 side shown in FIG.1 (c), to the cold junction part 42 side. Therefore, the buffer layer 20 having a higher resistance value than the thermoelectric material layer 30 can be obtained. Therefore, the insulation between the buffer layer 20 and the thermoelectric material layer 30 can be ensured without interposing the insulating layer between the buffer layer 20 and the thermoelectric material layer 30. Therefore, the thermoelectric characteristics in the horizontal direction with respect to the substrate 10 can be maintained.

Next, with reference to FIG.3 (b), this modification 2 forms the independent laminated part which comprises the buffer layer 20 in the block shape. In other points, it is the same as the thermoelectric conversion element 1 in embodiment of this invention mentioned above. The same member and the same function are given the same number, and the following description is omitted.
The “block shape” indicates a state in which a plurality of independent laminated portions 23 are regularly arranged at equal intervals in the BB line and CC line directions shown in FIG.

  By forming the independent laminated portion 23 in a block shape, the buffer layer 20 has a configuration in which no current flows in the BB line direction, that is, from the hot junction portion 41 side to the cold junction portion 42 side shown in FIG. can do. Furthermore, it is possible to prevent a current from flowing in the CC line direction. Therefore, the buffer layer 20 having a higher resistance value than the thermoelectric material layer 30 can be obtained. Therefore, the insulation between the buffer layer 20 and the thermoelectric material layer 30 can be ensured without interposing the insulating layer between the buffer layer 20 and the thermoelectric material layer 30. Therefore, the thermoelectric characteristics in the horizontal direction with respect to the substrate 10 can be further maintained.

  INDUSTRIAL APPLICABILITY The present invention can be used for a far-infrared camera or the like as a thermoelectric conversion element having excellent adhesion and thermoelectric properties between a substrate and a thermoelectric material layer.

DESCRIPTION OF SYMBOLS 1 Thermoelectric conversion element 10 Board | substrate 20 Buffer layer 21 Independent laminated part 22 Independent laminated part 23 Independent laminated part 30 Thermoelectric material layer 40 Electrode layer 41 Hot junction part 42 Cold junction part 50 Infrared absorption heating part 100 Thermoelectric conversion laminated structure 200 Infrared sensor

Claims (4)

  A substrate, a buffer layer formed by laminating a plurality of independent laminated portions made of Ti metal or Ti alloy, and one or two elements selected from the first group of Bi and Sb and Te and Se. A laminated structure for thermoelectric conversion, wherein a thermoelectric material layer containing one or two elements selected from the second group as an active ingredient is laminated in this order.   The thermoelectric conversion laminated structure according to claim 1 is formed with a certain length, and a hot junction part and a cold junction part are formed by laminating electrode layers on both ends of the thermoelectric conversion laminate structure, respectively. The thermoelectric conversion element characterized by the above-mentioned.   An infrared sensor comprising an infrared absorption heating part connected to the hot junction part of the thermoelectric conversion element according to claim 2.   A step of laminating and forming a plurality of independent laminated portions of Ti metal or Ti alloy on the substrate, and a buffer layer formed by mutual dispersion; and 1 or 2 selected from the first group of Bi and Sb via the buffer layer And a step of laminating a thermoelectric material layer containing two elements and one or two elements selected from the second group of Te and Se as active ingredients.

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