WO2024057611A1

WO2024057611A1 - Laminate

Info

Publication number: WO2024057611A1
Application number: PCT/JP2023/017594
Authority: WO
Inventors: 光太郎廣瀬; 真寛足立; 泰孝水野; 智哉佐伯; 勝己上坂; 恒博竹内
Original assignee: 住友電気工業株式会社; 学校法人トヨタ学園
Priority date: 2022-09-14
Filing date: 2023-05-10
Publication date: 2024-03-21

Abstract

This laminate comprises a plurality of material layers configured from a solid phase changing material that includes: a first base material element; and a second base material element different from the first base material element. The plurality of material layers include: a first material layer in which the content ratio of the first base material element is the largest; and a second material layer in which the content ratio of the first base material element is the smallest. A difference in the content ratios obtained by subtracting the content ratio of the first base material element in the second material layer from the content ratio of the first base material element in the first material layer is 10 at% or more.

Description

laminate

The present disclosure relates to a laminate. This application claims priority based on Japanese Application No. 2022-146482 filed on September 14, 2022, and incorporates all the contents described in the said Japanese application.

A silver chalcogenide material whose thermal conductivity changes depending on temperature has been disclosed (for example, Non-Patent Document 1).

A laminate according to the present disclosure includes a plurality of material layers comprised of a solid phase change material including a first matrix element and a second matrix element different from the first matrix element. The plurality of material layers include a first material layer having the highest content of the first base material element and a second material layer having the smallest content of the first base material element. The difference in the content ratio obtained by subtracting the content ratio of the first base material element in the second material layer from the content ratio of the first base material element in the first material layer is 10 at % or more.

FIG. 1 is a schematic side view showing the structure of the laminate according to the first embodiment. FIG. 2 is an enlarged view of a part of the laminate shown in FIG. 1. FIG. 3 is a schematic perspective view of the laminate shown in FIG. 1. FIG. 4 is a schematic side view showing the structure of the laminate according to the second embodiment. FIG. 5 is a schematic side view showing the structure of the laminate according to the third embodiment. FIG. 6 is a phase diagram of the solid phase change material in the silver chalcogenide-based material described above. FIG. 7 is a graph schematically showing the relationship between temperature and thermal conductivity when the composition ratio is in region R ₁ and region R ₃ . FIG. 8 is a graph schematically showing the relationship between temperature and thermal conductivity when the composition ratio is in region _R2 . FIG. 9 is a graph showing the relationship between temperature and thermal conductivity in Samples 1 to 6. FIG. 10 is a graph showing the relationship between temperature and thermal conductivity in Samples 7 to 12.

[Problems that this disclosure seeks to solve]
As disclosed in Non-Patent Document 1, the thermal conductivity of a solid phase change material such as a silver chalcogenide material changes sharply after a certain temperature. Therefore, it is difficult to apply such solid phase change materials to devices that involve thermal control such as thermoelectric conversion.

Therefore, one of the objects is to provide a laminate that can be easily applied to devices that require thermal control.

[Effects of this disclosure]
The laminate described above can be easily applied to devices that require thermal control.

[Description of embodiments of the present disclosure]
First, embodiments of the present disclosure will be listed and described. A laminate according to the present disclosure includes a plurality of material layers composed of a solid phase change material including a first base material element and a second base material element different from the first base material element. The plurality of material layers include a first material layer having the highest content of the first base material element and a second material layer having the smallest content of the first base material element. The difference in the content ratio obtained by subtracting the content ratio of the first base material element in the second material layer from the content ratio of the first base material element in the first material layer is 10 at % or more.

Some devices such as lasers require temperature control functions, such as keeping their own temperature constant. To adjust the temperature, heating and cooling are performed using heaters, cooling elements, etc., and heat insulation and heat dissipation are increased using heat insulating materials and heat sinks. Here, the present inventors focused on solid phase change materials whose thermal conductivity varies depending on temperature. By combining these materials with elements, heating and cooling can be performed efficiently. However, because the thermal conductivity changes sharply with respect to temperature, it is difficult to use for device temperature control. Therefore, the present inventors thought to improve this drawback and came up with the present invention.

The laminate according to the present disclosure includes:
(1) A plurality of material layers constituted of a solid phase change material including a first matrix element and a second matrix element different from the first matrix element. The plurality of material layers includes a first material layer having the largest content ratio of the first base material element and a second material layer having the smallest content ratio of the first base material element. The present inventors have discovered that when a phase transformation occurs in a solid phase change material, the carrier concentration within the phase changes, and as a result, the thermal conductivity changes. Therefore, in order to avoid sudden changes in the thermal conductivity of the thermal control material when the environmental temperature changes, a uniform thermal control material, that is, a thermal control material as a bulk material, has a multilayer structure consisting of multiple material layers. Therefore, it was decided to provide a difference in the content ratio of the first base material element between the first material layer and the second material layer. By doing so, a difference in the degree of phase transformation is created between the first material layer and the second material layer, and a difference in thermal conductivity is created, resulting in a sudden increase in thermal conductivity at a certain temperature. We thought that it would be possible to avoid changes in Then, the present inventors have further studied and determined that the difference in the content ratio between the first material layer and the second material layer after subtracting the content ratio of the first base material element is 10 at% or more. We have found that by doing this, it is possible to smooth out changes in thermal conductivity when the environmental temperature changes in a laminate as a thermal control material. According to such a laminate, even in a situation where the environmental temperature changes, the thermal conductivity can be smoothly changed according to the environmental temperature, and the temperature of the device can be efficiently controlled. Therefore, such a laminate can be easily applied to devices that require thermal control. Note that the laminate in the present disclosure refers to a laminate in which a plurality of layers having a characteristic that thermal conductivity changes depending on temperature, external voltage, etc. are laminated.

(2) In (1) above, a diffusion suppression layer is provided between the first material layer and the second material layer and suppresses diffusion of atoms contained in each material layer to other material layers. Further provision may be made. By doing so, atoms contained in each material layer diffuse into other material layers during phase transformation, specifically, atoms contained in the first material layer diffuse into the second material layer. By suppressing diffusion and diffusion of atoms contained in the second material layer into the first material layer, it is possible to reduce the possibility that the composition of the first material layer and the composition of the second material layer will change. . That is, by arranging such a diffusion suppressing layer, reactions between the material layers and reactions with other materials can be suppressed, and deterioration due to phase transformation during repeated use can be prevented.

(3) In (1) or (2) above, the solid phase change material may include a silver chalcogenide-based material. Such materials can be easily applied to devices involving thermal control.

(4) In (3) above, the first base material element and the second base material element may each be an element selected from the group consisting of sulfur, selenium, and tellurium. The solid phase change material may be represented by Ag ₂ S _x Se _1-x , Ag ₂ S _x Te _1-x or Ag ₂ Se _x Te _1-x . x may have a relationship of 0≦x≦1. A laminate including multiple material layers made of such solid phase change materials can smoothly change thermal conductivity even under conditions where the environmental temperature changes, and can efficiently control the temperature of the device. can.

(5) In any one of (1) to (4) above, each of the plurality of material layers may have a thickness of 10 μm or more and 5 mm or less. By setting the thickness of the material layer to 10 μm or more, the thickness of the material layer can be ensured to be greater than a region where phase transformation is unlikely to occur from the contacting diffusion suppressing layer when the diffusion suppressing layer comes into contact with the material layer. Further, by setting the thickness of the material layer to 5 mm or less, precipitation of elements within a single material layer due to ion conduction when a temperature difference is applied can be suppressed, and reliability can be improved.

(6) In (2) above, the diffusion suppressing layer may be made of at least one of SiO ₂ , SiN, SiON, and epoxy resin. A diffusion suppressing layer made of such a material can more reliably suppress diffusion of atoms contained in each material layer to other material layers.

(7) In (2) above, the thickness of the diffusion suppressing layer is 10 nm or more, and may be thinner than the thickest material layer among the plurality of material layers. By setting the thickness of the diffusion suppressing layer to 10 nm or more, it is possible to reliably suppress diffusion of atoms between each layer. Moreover, by making the thickness of the diffusion suppression layer thinner than the thickest material layer, the influence of the diffusion suppression layer on the thermal conductivity of the laminate can be reduced.

(8) In any of (1) to (7) above, the plurality of material layers is a third material layer made of a solid phase change material containing a first base material element and a second base material element. It may further include. In the thickness direction of the plurality of material layers, the first material layer, the third material layer, and the second material layer may be arranged in this order. By doing so, the content ratio of the first base material element in the laminate can be gradually changed, and the change in thermal conductivity between each material layer can be made smoother. Therefore, the temperature of the device can be controlled more efficiently.

(9) In (8) above, the atoms are arranged between the first material layer and the third material layer and between the third material layer and the second material layer, and are included in each material layer. It may further include a diffusion suppression layer that suppresses the diffusion of . By doing so, the diffusion of atoms between the first material layer and the third material layer and the diffusion of atoms between the third material layer and the second material layer are efficiently suppressed. be able to. That is, the atoms contained in the first material layer diffuse into the third material layer, the atoms contained in the third material layer diffuse into the first material layer, and the atoms contained in the third material layer diffuse into the third material layer. Diffusion into the second material layer and diffusion of atoms contained in the second material layer into the third material layer can be efficiently suppressed.

(10) In any of (1) to (7) above, the plurality of material layers is a third material layer made of a solid phase change material containing a first base material element and a second base material element. It may further include. In the thickness direction of the plurality of material layers, the first material layer, the second material layer, and the third material layer may be arranged in this order. By doing this, even if the third material layer is arranged in a part other than between the first material layer and the second material layer, the first material layer and the second material layer In this case, it is possible to smooth the change in thermal conductivity when the environmental temperature changes. Therefore, the temperature of the device can be controlled more efficiently.

(11) In (10) above, a diffusion suppression layer is provided between the second material layer and the third material layer and suppresses diffusion of atoms contained in each material layer to other material layers. Further provision may be made. By doing so, it is possible to efficiently suppress the diffusion of atoms between the second material layer and the third material layer. That is, it is possible to efficiently suppress the diffusion of atoms contained in the second material layer to the third material layer and the diffusion of atoms contained in the third material layer to the second material layer.

[Details of embodiments of the present disclosure]
Next, embodiments of the laminate of the present disclosure will be described with reference to the drawings. In the following drawings, the same or corresponding parts are given the same reference numerals, and the description thereof will not be repeated.

(Embodiment 1)
Embodiment 1, which is an embodiment of a laminate according to the present disclosure, will be described with reference to FIG. 1. FIG. 1 is a schematic side view showing the structure of the laminate according to the first embodiment. In FIG. 1, the thickness of each layer is exaggerated for ease of understanding. FIG. 2 is an enlarged view of a part of the laminate shown in FIG. 1. FIG. 3 is a schematic perspective view of the laminate shown in FIG. 1. In FIG. 1 and the figures shown below, the thickness direction of the laminate is shown in the Z direction. The X direction and the Y direction are perpendicular to the Z direction. The XY plane is a plane perpendicular to the Z direction.

Referring to FIGS. 1, 2, and 3, a laminate 10a according to the first embodiment has a block shape and is composed of a plurality of material layers. In this embodiment, the number of material layers included in the laminate 10a is ten. The laminate 10a includes a material layer 11a, a material layer 11b, a material layer 11c, a material layer 11d, a material layer 11e, a material layer 11f, a material layer 11g, a material layer 11h, a material layer 11i, and a material layer 11j. Each of the material layers 11a to 11j is arranged in the thickness direction. The material layers 11a to 11j are, in the Z direction, material layer 11a, material layer 11b, material layer 11c, material layer 11d, material layer 11e, material layer 11f, material layer 11g, material layer 11h, material layer 11i, and The material layers 11j are arranged in this order. In this embodiment, the first surface 12a located on one side in the thickness direction of the material layer 11a and the second surface 13j located on the other side in the thickness direction of the material layer 11j are exposed to the outside. There is. That is, material layers 11b to 11i are arranged in order between material layer 11a and material layer 11j. Further, the material layer 11a and the material layer 11j are arranged at both ends of the laminate 10a in the thickness direction. In addition, in the arrangement relationship between the first material layer, the second material layer, and the third material layer, in the Z direction that is the thickness direction of the plurality of material layers 11a to 11j, for example, the first material layer 11a, the third material layer 11b, and the second material layer 11j are arranged in this order. Such a laminate 10a, for example, attaches a first electrode to the material layer 11a, attaches a second electrode to the material layer 11j, and applies thermal energy (temperature difference) between the material layer 11a and the material layer 11j. By applying (applying), electric energy generated between the first electrode and the second electrode is obtained. Note that among the plurality of material layers, the material layer with the largest content ratio of the first base material element is the first material layer 11a, and the material layer with the smallest content ratio of the first base material element is the second material layer. This is the material layer 11j.

When viewed from the Z direction, the outer shapes of the material layers 11a to 11j are the same. In this embodiment, the outer shapes of the material layers 11a to 11j are all rectangular when viewed from the Z direction. Note that the external shape of the laminate 10a viewed from the Z direction is not limited to a rectangular shape, and may be, for example, a round shape, an elliptical shape, or a polygonal shape such as a triangular or hexagonal shape. You can.

In this embodiment, the material layers 11a to 11j have the same thickness. The thickness T ₁ of the material layer 11a, that is, the distance between the first surface 12a located on one side in the thickness direction of the material layer 11a and the second surface 13a located on the other side in the thickness direction is 10 μm. It is not less than 5 mm. In this embodiment, the thickness _T1 of the material layer 11a is 100 μm.

The laminate 10a includes a plurality of

diffusion suppressing layers

21a, 21b, 21c, 21d, 21e, 21f, 21g, 21h, and 21a. In this embodiment, the laminate 10a includes nine diffusion suppressing layers 21a to 21i. Each of the diffusion suppressing layers 21a to 21i is arranged between the material layer 11a to the material layer 11j, respectively, in the Z direction. Specifically, the diffusion suppressing layer 21a is arranged between the material layer 11a and the material layer 11b. A diffusion suppressing layer 21b is arranged between the material layer 11b and the material layer 11c. A diffusion suppressing layer 21c is arranged between the material layer 11c and the material layer 11d. A diffusion suppressing layer 21d is arranged between the material layer 11d and the material layer 11e. A diffusion suppressing layer 21e is arranged between the material layer 11e and the material layer 11f. A diffusion suppressing layer 21f is arranged between the material layer 11f and the material layer 11g. A diffusion suppressing layer 21g is arranged between the material layer 11g and the material layer 11h. A diffusion suppressing layer 21h is arranged between the material layer 11h and the material layer 11i. A diffusion suppressing layer 21i is arranged between the material layer 11i and the material layer 11j. That is, the diffusion suppressing layers 21a to 21i are sandwiched between the material layers 11a to 11j, respectively. Note that a diffusion suppressing layer is disposed between the material layer 11a and the material layer 11b, and a diffusion suppressing layer is also disposed between the material layer 11b and the material layer 11c. Diffusion suppression layers 21a to 21i each suppress diffusion of atoms contained in each material layer 11a to 11j to other material layers 11a to 11j. Specifically, the diffusion suppression layer 21a suppresses the diffusion of atoms contained in the material layer 11a into the material layer 11b and the diffusion of atoms contained in the material layer 11b into the material layer 11a. The diffusion suppression layer 21b suppresses the diffusion of atoms contained in the material layer 11b into the material layer 11c and the diffusion of atoms contained in the material layer 11c into the material layer 11b. The diffusion suppression layer 21c suppresses the diffusion of atoms contained in the material layer 11c to the material layer 11d and the diffusion of atoms contained in the material layer 11d to the material layer 11c. The diffusion suppression layer 21d suppresses the diffusion of atoms contained in the material layer 11d into the material layer 11e and the diffusion of atoms contained in the material layer 11e into the material layer 11d. The diffusion suppression layer 21e suppresses the diffusion of atoms contained in the material layer 11e into the material layer 11f and the diffusion of atoms contained in the material layer 11f into the material layer 11e. The diffusion suppression layer 21f suppresses the diffusion of atoms contained in the material layer 11f into the material layer 11g and the diffusion of atoms contained in the material layer 11g into the material layer 11f. The diffusion suppression layer 21g suppresses the diffusion of atoms contained in the material layer 11g into the material layer 11h and the diffusion of atoms contained in the material layer 11h into the material layer 11g. The diffusion suppression layer 21h suppresses the diffusion of atoms contained in the material layer 11h into the material layer 11i and the diffusion of atoms contained in the material layer 11i into the material layer 11h. The diffusion suppression layer 21i suppresses the diffusion of atoms contained in the material layer 11i into the material layer 11j and the diffusion of atoms contained in the material layer 11j into the material layer 11i.

In this embodiment, each of the diffusion suppressing layers 21a to 21i has the same thickness. The thickness T ₂ of the diffusion suppressing layer 21a, that is, the distance between the first surface 22a located on one side in the thickness direction of the diffusion suppressing layer 21a and the second surface 23a located on the other side in the thickness direction is , 10 nm or more. Further, the thickness T ₂ of the diffusion suppressing layer 21a is thinner than the thickest material layer among the material layers 11a to 11j. In this embodiment, the thickness _T2 of the diffusion suppressing layer 21a is 10 μm.

The diffusion suppression layers 21a to 21i are each made of the same material. In this embodiment, each of the diffusion suppressing layers 21a to 21i is made of SiO ₂ (silicon dioxide). Since the diffusion suppression layers 21a to 21i made of such materials have high insulating properties, they can more reliably suppress the diffusion of atoms contained in each material layer 11a to 11j to other material layers 11a to 11j. Can be done.

Each of the material layers 11a to 11j is composed of a solid phase change material containing a first base material element and a second base material element. That is, the laminate 10a according to the present disclosure has a multilayer structure. In this embodiment, the first base material element is S (sulfur). The second base material element is Se (selenium). The third base material element is Ag (silver). Each of the solid phase change materials constituting the material layers 11a to 11j included in the laminate 10a of the first embodiment includes a silver chalcogenide-based material. Such materials can be easily applied to devices involving thermal control. In this embodiment, the solid phase change material is represented by Ag ₂ S _x Se _1-x . x has a relationship of 0≦x≦1.

Here, in the laminate 10a of the first embodiment, the first base material element in the second material layer 11j is determined from the content ratio of S (sulfur), which is the first base material element in the first material layer 11a. The difference in content after subtracting a certain S content is 10 at % or more. Specifically, the content ratios of the first base material element and the second base material element in each of the material layers 11a to 11j are as shown in Sample 1, which will be described later.

According to the laminate 10a having such a configuration, even in a situation where the environmental temperature changes, the thermal conductivity can be smoothly changed according to the environmental temperature, and the temperature of the device can be efficiently controlled. Therefore, such a laminate 10a can be easily applied to devices that require thermal control.

The present embodiment includes diffusion suppression layers 21a to 21i that are disposed between the first material layer 11a and the second material layer 11j and suppress diffusion of atoms between the respective material layers 11a to 11j. Therefore, it is possible to suppress the diffusion of atoms contained in each material layer 11a to 11j to other material layers during phase transformation, and reduce the possibility that the composition of each material layer 11a to 11j will change. . That is, by arranging the diffusion suppressing layers 21a to 21i in this manner, reactions between the material layers 11a to 11j and reactions with other materials can be suppressed, and deterioration due to phase transformation during repeated use can be prevented. can.

In this embodiment, the first base material element and the second base material element are sulfur and selenium, respectively. The solid phase change material is represented by Ag ₂ S _x Se _1-x , where x has the relationship 0≦x≦1. The laminate 10a, which includes a plurality of material layers 11a to 11j made of such solid phase change materials, smoothly changes thermal conductivity even in situations where the environmental temperature changes, and efficiently controls the temperature of the device. can be done.

In the present embodiment, each of the plurality of material layers 11a to 11j has a thickness of 10 μm or more and 5 mm or less. By setting the thickness of the material layers 11a to 11j to 10 μm or more, the material layers 11a to 11j can ensure a thickness greater than a region where phase transformation is difficult to occur from the contacting diffusion suppressing layers 21a to 21i. Furthermore, by setting the thickness of the material layers 11a to 11j to 5 mm or less, precipitation of elements within a single material layer due to ion conduction when a temperature difference is applied can be suppressed, and reliability can be improved. .

In this embodiment, the thickness of the diffusion suppressing layers 21a to 21i is 10 nm or more, and is thinner than the thickest material layer 11a to 11j among the plurality of material layers. By setting the thickness of the diffusion suppressing layers 21a to 21i to 10 nm or more, it is possible to reliably suppress diffusion of atoms contained in each material layer 11a to 11j to other material layers 11a to 11j. Further, by making the thickness of the diffusion suppressing layers 21a to 21i thinner than the thickest material layers 11a to 11j, the influence of the diffusion suppressing layers 21a to 21i on the thermal conductivity of the laminate 10a can be reduced.

In this embodiment, the plurality of material layers 11a to 11j include a third material layer 11c made of a solid phase change material containing a first base material element and a second base material element. In the thickness direction of the plurality of material layers, the first material layer 11a, the third material layer 11b, and the second material layer 11j are arranged in this order. Therefore, by gradually changing the content ratio of the first base material element in the laminate 10a, it is possible to more smoothly change the thermal conductivity between the

material layers

11a, 11b, and 11j. Therefore, the temperature of the device can be controlled more efficiently.

In the above embodiment, the content ratio of the first base material element (S) gradually decreases in the thickness direction of the laminate 10a from the material layer 11a, which is the lowest layer, and It was decided that the content ratio of the base material element (Se) was increased. Not limited to this, conversely, the content ratio of the first base material element (S) decreases from the material layer 11j which is the uppermost layer, and the content ratio of the second base material element (Se) increases. It may also be a thing. Furthermore, instead of the content ratio of the first base material element and the content ratio of the second base material element changing gradually for each adjacent material layer, the content ratio of the first base material element differs as in Sample 6, which will be described later. The material layers may be randomly arranged. That is, the material layer having the highest or lowest content of the first base material element does not need to be disposed at one end in the thickness direction. The same applies to Embodiment 2 and Embodiment 3, which will be described later.

(Embodiment 2)
Embodiment 2, which is another embodiment, will be described. FIG. 4 is a schematic side view showing the structure of the laminate according to the second embodiment. The laminate in Embodiment 2 basically has the same configuration as Embodiment 1, and produces the same effects. However, the number of layers in the laminate of the second embodiment is different from that of the first embodiment.

Referring to FIG. 4, laminate 10b includes a first material layer 11a and a second material layer 11b made of a solid phase change material containing a first base material element and a second base material element. . That is, the laminate 10b has a two-layer structure. A diffusion suppressing layer 21a is arranged between the first material layer 11a and the second material layer 11b. The content ratio of the first base material element in the first material layer 11a is larger than the content ratio of the first base material element in the second material layer 11b. The difference in the content ratio obtained by subtracting the content ratio of the first base material element in the second material layer 11b from the content ratio of the first base material element in the first material layer 11a is 10 at % or more.

In this way, the laminate 10b may be composed of two material layers having the above relationship and one diffusion suppressing layer. By doing so as well, the temperature of the device can be efficiently controlled.

(Embodiment 3)
Embodiment 3, which is another embodiment, will be described. FIG. 5 is a schematic side view showing the structure of the laminate according to the third embodiment. The laminate in Embodiment 3 basically has the same configuration as Embodiment 1, and produces the same effects. However, the laminate of the third embodiment is different from the first embodiment in the number of layers and the composition.

Referring to FIG. 5, a laminate 10c according to the third embodiment has eleven material layers, unlike the first embodiment. That is, the laminate 10c in the third embodiment is composed of material layers 11a to 11k. In this embodiment, the second surface 13k of the material layer 11k is exposed. Then, a diffusion suppressing layer 21j is arranged between the material layer 11j and the material layer 11k. Further, unlike the case of Embodiment 1, the first base material element is S, the second base material element is Te, and the third base material element is Ag. Each of the solid phase change materials constituting the material layers 11a to 11k included in the laminate 10c of the third embodiment is represented by Ag ₂ S _x Te _1-x . x has a relationship of 0≦x≦1. Further, the material of each of the diffusion suppressing layers 21a to 21j is SiN (silicon nitride).

With the laminate 10c having such a configuration, even in situations where the environmental temperature changes, the thermal conductivity can be smoothly changed according to the environmental temperature, and the temperature of the device can be efficiently controlled.

(Other embodiments)
In addition, in the above embodiment, the diffusion suppressing layer is made of _SiO ₂ or SiN, but the diffusion suppressing layer is not limited to this. It may be composed of at least one of the following. A diffusion suppressing layer made of such a material can more reliably suppress diffusion of atoms contained in each material layer to other material layers.

Note that in the above embodiments, examples are shown in which the number of material layers is 2, 10, or 11, but the invention is not limited to this. The material layer may have at least two or more layers, and among the plurality of material layers, the material layer with the largest content of the first base material element is defined as the first material layer, and the material layer containing the first base material element is defined as the first material layer. When the material layer with the smallest ratio is taken as the second material layer, the content ratio of the first base material element in the second material layer is subtracted from the content ratio of the first base material element in the first material layer. It is sufficient if the difference in the content ratio is 10 at% or more. The first base material element and the second base material element are each selected from the group consisting of S, Se, and Te.

FIG. 6 is a phase diagram of the solid phase change material in the silver chalcogenide-based material described above. In FIG. 6, the horizontal axis indicates the content ratio of atoms represented by x, and the vertical axis indicates temperature (° C.). Note that in FIG. 6, hatched regions indicate regions that can be both an α phase and a β phase, both of which will be described later.When the temperature is raised, the α phase becomes the α phase, and when the temperature is lowered, the β phase becomes the hatched region. That is, it is a region of hysteresis in phase transformation. Referring to FIG. 6, a Te--Se based solid phase change material (Ag ₂ _Tex Se _1-x ) shown in region R ₁ and a Se-S-based solid phase change material (Ag ₂ Se _x S shown in region R ₂ In the S _- Te-based solid phase change material (Ag ₂ S _x Te _1-x ) shown in region R ₃ and region R 3, the first base material element and the second base material element are S, Se, When two different elements are selected from Te and the content ratio is changed, the phase transforms into an α phase, which is a high temperature phase, and a β phase, which is a low temperature phase, depending on the temperature. The carrier concentration changes due to phase transformation, and as a result, the thermal conductivity changes. The point defects (vacancies and surplus elements) differ depending on the composition, and the thermal conductivity κ differs.

FIG. 7 is a graph schematically showing the relationship between temperature and thermal conductivity when the composition ratio is in region R ₁ and region R ₃ . FIG. 8 is a graph schematically showing the relationship between temperature and thermal conductivity when the composition ratio is in region _R2 . In FIGS. 7 and 8, the horizontal axis represents temperature, and the vertical axis represents thermal conductivity. Referring to FIG. 7, in region R ₁ and region R ₃ , the thermal conductivity is high when the temperature is low and low when the temperature is high. Further, referring to FIG. 8, in region _R2 , the thermal conductivity is low when the temperature is low and becomes high when the temperature is high. Depending on each composition, that is, the content ratio of the first base material element, the ratio occupied by the α phase, which is a high temperature phase, and the β phase, which is a low temperature phase, changes, and the thermal conductivity changes accordingly. In the laminate according to the present disclosure, the thermal conductivity is varied by changing the composition of this base material element, thereby avoiding a sudden change in the thermal conductivity.

Further, in the above embodiments, the solid phase change material is represented by Ag ₂ S _x Se _1-x , where x has a relationship of 0≦x≦1, or Ag ₂ S _x Te _1-x . _x , where x has a relationship of 0≦x≦1, but the solid phase change material is not limited to this, but the solid phase change material may be Ag ₂ Se _x S _1-x , Ag ₂ Te _x S _1-x Alternatively, it may be represented by Ag ₂ Se _x Te _1-x . x may have a relationship of 0≦x≦1. Note that it is understood from FIG. 6 that Ag ₂ Se _x Te _1-x has similar effects. A laminate containing multiple material layers composed of such solid phase change materials can smoothly change thermal conductivity depending on the environmental temperature even in situations where the environmental temperature changes, and it is possible to control the temperature of the device. can be done efficiently.

Samples 1 to 6 were prepared as shown in Table 1. The first base material element is sulfur, the second base material element is selenium, and one material layer is expressed as Ag ₂ S _x Se _1-x . In the arrangement of material layers in Table 1, the upper layer corresponds to the upper layer and the lower layer corresponds to the lower layer.

(Sample 1)
As Sample 1, 10 material layers were prepared as shown in Table 1. The content ratio (x) of the first base material element in the material layer is, from the bottom, x=0.950, x=0.930, x=0.910, x=0.890, x=0.870, x =0.850, x=0.830, x=0.810, x=0.790, x=0.770. Among the 10 material layers, the layer with the largest first base material element (S) is the first material layer 11a (material layer L ₁₀ shown in Table 1), and the first base material element (S) The smallest layer is the second material layer 11j (material layer L ₁ shown in Table 1). The third material layer 11b is, for example, material layer _L9 shown in Table 1. The difference in the content ratio obtained by subtracting the content ratio of S, which is the first base material element, in the second material layer 11j from the content ratio of S, which is the first base material element, in the first material layer 11a is 18 at%. It is. The difference in content ratio is shown in the lower column of Table 1.

Note that such a laminate 10a is manufactured as follows. First, powders of Ag ₂ S and Ag ₂ Se as raw materials for the material layer and SiO ₂ powder as raw materials for the diffusion suppressing layer are prepared. Then, each raw material powder is weighed and mixed to achieve the content ratio of each layer, that is, the element ratio specified in each layer. In this way, powders constituting each layer are prepared. Thereafter, the powders constituting each layer are sealed in a vacuum cylinder and heated at 150K to form an alloy. The alloy is then removed from the vacuum cylinder and hand milled into a fine powder.

Next, the powder thus obtained is sintered. Specifically, a die with a diameter of 50 mm is prepared, a powder constituting the first material layer is put therein, and an SiO ₂ powder constituting the first diffusion suppressing layer is put thereon. Thereafter, powder constituting the next material layer is placed, and SiO ₂ powder constituting the diffusion suppressing layer is placed thereon again. In this way, the powder constituting each material layer and the SiO ₂ powder constituting the diffusion suppressing layer are alternately introduced and packed into the die. In this embodiment, the material was placed into the die so that the thickness of the material layer was 1 mm or less, and the thickness of the diffusion suppressing layer was 0.1 mm or less.

After that, sintering was performed. Regarding sintering, hot pressing was performed at a temperature in a range of 600 K or more and 1500 K or less, and under a uniaxial pressure of 10 MPa or more and 100 MPa or less. The holding time was 2 hours, and the test was carried out under an Ar (argon) gas atmosphere. After undergoing a sintering process and being naturally cooled, it was taken out from the die to obtain a laminate according to Sample 1. The obtained laminate has the configuration shown in FIG. 1. Hereinafter, Sample 2, Sample 3, and Sample 6 have the same configuration.

(Sample 2)
As Sample 2, ten material layers were prepared according to the compositions shown in Table 1 below. Then, a laminate according to Sample 2 was obtained using the same manufacturing method as Sample 1. Among the 10 material layers, the layer with the largest first base material element (S) is the first material layer 11a (material layer L ₁₀ shown in Table 1), and the first base material element (S) The smallest layer is the second material layer 11j (material layer L ₁ shown in Table 1). The third material layer 11b is, for example, material layer _L9 shown in Table 1.

(Sample 3)
As Sample 3, ten material layers were prepared according to the compositions shown in Table 1 below. Then, a laminate according to Sample 3 was obtained using the same manufacturing method as Sample 1. Among the 10 material layers, the layer with the largest first base material element (S) is the first material layer 11a (material layer L ₁₀ shown in Table 1), and the first base material element (S) The smallest layer is the second material layer 11j (material layer L ₁ shown in Table 1). The third material layer 11b is, for example, material layer _L9 shown in Table 1.

(Sample 4)
As Sample 4, two material layers were prepared according to the compositions shown in Table 1 below. Then, a laminate according to Sample 4 was obtained using the same manufacturing method as Sample 1. The obtained laminate has the configuration shown in FIG. 4. Hereinafter, sample 10 has a similar configuration. The first material layer 11a is the material layer _L1 shown in Table 1, and the second material layer 11b is the material layer _L2 shown in Table 1.

(Sample 5)
A material consisting of only one material layer was prepared as Sample 5 according to Table 1 shown below. Then, a material related to Sample 5 was obtained using the same manufacturing method as Sample 1.

(Sample 6)
As Sample 6, 10 material layers were prepared according to the compositions shown in Table 1 below. Then, a laminate 10c of Sample 6 was obtained using the same manufacturing method as Sample 1. Among the 10 material layers, the layer with the largest first base material element (S) is the first material layer 11a (material layer L ₁₀ shown in Table 1), and the first base material element (S) The smallest layer is the second material layer 11f (material layer L ₅ shown in Table 1). The third material layer 11b is, for example, material layer _L9 shown in Table 1.

Samples 7 to 12 were prepared as shown in Table 2. The first matrix element is sulfur, the second matrix element is tellurium, and one material layer is designated as Ag ₂ S _x Te _1-x . In the arrangement of the material layers in Table 2, the upper layer corresponds to the upper layer and the lower layer corresponds to the lower layer.

(Sample 7)
As Sample 7, 11 material layers were prepared according to the compositions shown in Table 2 below. Then, a laminate according to Sample 7 was obtained using the same manufacturing method as Sample 1. The obtained laminate has the configuration shown in FIG. 5. Hereinafter, Sample 8, Sample 9, and Sample 12 have the same configuration. Among the 11 material layers, the layer with the largest first base material element (S) is the first material layer 11a (material layer L ₁₁ shown in Table 1), and the first base material element (S) The smallest layer is the second material layer 11k (material layer L ₁ shown in Table 1). The third material layer 11b is, for example, material layer _L10 shown in Table 2.

(Sample 8)
As Sample 8, 11 material layers were prepared according to the compositions shown in Table 2 below. Then, a laminate according to Sample 8 was obtained using the same manufacturing method as Sample 1. Among the 11 material layers, the layer with the largest first base material element (S) is the first material layer 11a (material layer L ₁₁ shown in Table 1), and the first base material element (S) The smallest layer is the second material layer 11k (material layer L ₁ shown in Table 1). The third material layer 11b is, for example, material layer _L10 shown in Table 2.

(Sample 9)
As Sample 9, 11 material layers were prepared according to the compositions shown in Table 2 below. Then, a laminate according to Sample 9 was obtained using the same manufacturing method as Sample 1. Among the 11 material layers, the layer with the largest first base material element (S) is the first material layer 11a (material layer L ₁₁ shown in Table 1), and the first base material element (S) The smallest layer is the second material layer 11k (material layer L ₁ shown in Table 1). The third material layer 11b is, for example, material layer _L10 shown in Table 2.

(Sample 10)
As Sample 10, two material layers were prepared according to the compositions shown in Table 2 below. Then, a laminate according to Sample 10 was obtained using the same manufacturing method as Sample 1. The first material layer 11a is the material layer _L2 shown in Table 2, and the second material layer 11b is the material layer _L1 shown in Table 2.

(Sample 11)
A material consisting of only one material layer was prepared as Sample 11 according to Table 2 shown below. Then, a laminate according to Sample 11 was obtained using the same manufacturing method as Sample 1.

(Sample 12)
As Sample 12, 11 material layers were prepared according to the compositions shown in Table 2 below. Then, a laminate according to Sample 12 was obtained using the same manufacturing method as Sample 1. The first material layer 11a is the material layer _L11 shown in Table 2, and the second material layer 11b is the material layer _L6 shown in Table 2. The third material layer 11b is, for example, material layer _L10 shown in Table 2.

Regarding the measurement of the composition, that is, the content ratio of each element in the material layer, it is a schematic diagram showing the results of EDX (Energy Dispersive X-ray spectrometry). EDX was measured by taking a TEM (Transmission Electron Microscope) image of a part of the laminate. For taking the TEM image, JEM-2800 (manufactured by JEOL Ltd.) was used, and the measurement conditions were an accelerating voltage of 200 kV, a probe size of 0.5 nm, and a CL aperture of 3. In addition, the conditions for detecting atoms by EDX are as follows: EDX (manufactured by Thermo Fisher Scientific Co., Ltd.) is used, and the measurement conditions are as follows: spot size is 0.5 nm, CL aperture is 3, and analysis mode is mapping. The analysis time was 20 minutes. Then, quantitative analysis was performed on the EDX measurement spectrum using the fitting function of the device.

Regarding the measurement of thermal conductivity, GH-1 manufactured by Advance Riko Co., Ltd. was used as a steady method thermal conductivity measuring device. Then, a high temperature side heater, a sample, a heat flux meter, and a low temperature side heater were prepared and the sample was set. The measurement was carried out at a temperature of 100°C or more and 150°C or less for the Ag-S-Se system, and a range of 60°C or more and 110°C or less for the Ag-S-Te system. The measurement was performed three times, and the average value was calculated. Further, the thickness of each material layer and the diffusion suppressing layer was determined using an optical microscope or a scanning electron microscope (SEM).

The evaluation results for samples 1 to 6 are shown in FIG. FIG. 9 is a graph showing the relationship between temperature and thermal conductivity in Samples 1 to 6. In FIG. 9, the horizontal axis indicates temperature (° C.), and the vertical axis indicates thermal conductivity (W/mK). Referring to FIG. 9, Sample 1 has a difference in content ratio of 18 at%, Sample 2 has a difference in content ratio of 10.8 at%, Sample 4 has a difference in content ratio of 12 at%, and Sample 4 has a difference in content ratio of 12 at%. Regarding sample 6, which has a content of 10.8 at%, the difference in content ratio is 10 at% or more, and the change in thermal conductivity is smooth. Here, a smooth change in thermal conductivity means that when the thermal conductivity changes from the minimum value to the maximum value, the amount of change relative to the difference between the maximum value and the minimum value changes from 10% to 90%. This refers to a case where the temperature changes by 10°C or more. On the other hand, the change in thermal conductivity is steep for Sample 3, where the difference in content ratio is 4 at %, and Sample 5, which is a bulk material where the difference in content ratio is 0. This is considered to be because in Sample 3 and Sample 5, the difference in the content ratio in each material layer is small or there is no difference in the content ratio, so that the phase transformation temperatures are close. Furthermore, as shown in samples 1 to 3, the material layers may be arranged in the order of the content ratio of the first base material element, and as shown in sample 6, the material layers may be arranged in the order of the content ratio of the first base material element. It can be seen that the content ratios of the elements may be in random order.

The evaluation results for samples 7 to 12 are shown in FIG. FIG. 10 is a graph showing the relationship between temperature and thermal conductivity in Samples 7 to 12. In FIG. 10, the horizontal axis represents temperature (° C.), and the vertical axis represents thermal conductivity (W/mK). Referring to FIG. 10, sample 7 has a difference in content ratio of 20 at%, sample 8 has a difference in content ratio of 10 at%, sample 10 has a difference in content ratio of 10 at%, and sample 10 has a difference in content ratio of 10 at%. For sample 12, the difference in content ratio is 10 at % or more, and the change in thermal conductivity is smooth. On the other hand, the change in thermal conductivity is steep for sample 9 where the difference in content ratio is 2 at % and sample 11 of bulk material where the difference in content ratio is 0. This is considered to be because in sample 9 and sample 11, the difference in the content ratio in each material layer is small or there is no difference in the content ratio, so that the phase transformation temperatures are close. Further, as shown in Samples 7 to 9, the material layers may be arranged in the order of the content ratio of the first base material element, and as shown in Sample 12, the material layers may be arranged in the order of the content ratio of the first base material element. It can be seen that the content ratios of the elements may be in random order.

As described above, according to the laminate according to the present disclosure, the temperature of the device can be controlled more efficiently.

It should be understood that the embodiments disclosed herein are illustrative in all respects and are not restrictive in any respect. The scope of the present invention is defined not by the above description but by the claims, and is intended to include meanings equivalent to the claims and all changes within the scope.

10a, 10b, 10c laminate, 11a material layer, 11b material layer, 11c material layer, 11d material layer, 11e material layer, 11f material layer, 11g material layer, 11h material layer, 11i material layer, 11j material layer, 11k material Layer, 12a, 22a First surface, 13a, 13j, 13k, 23a Second surface, 21a Diffusion suppression layer, 21b Diffusion suppression layer, 21c Diffusion suppression layer, 21d Diffusion suppression layer, 21e Diffusion suppression layer, 21f Diffusion suppression layer, 21g diffusion suppression layer, 21h diffusion suppression layer, 21i diffusion suppression layer, 21j diffusion suppression layer, T ₁ , T ₂ thickness, R ₁ , R ₂ , R ₃ region

Claims

a plurality of material layers composed of a solid phase change material including a first matrix element and a second matrix element different from the first matrix element;
The plurality of material layers are
a first material layer having the highest content ratio of the first base material element;
a second material layer having the smallest content of the first base material element,
The difference in the content ratio obtained by subtracting the content ratio of the first base material element in the second material layer from the content ratio of the first base material element in the first material layer is 10 at% or more, laminate.
2. The method according to claim 1, further comprising a diffusion suppressing layer disposed between the first material layer and the second material layer and suppressing diffusion of atoms contained in each material layer to other material layers. The described laminate.
The laminate according to claim 1, wherein the solid phase change material includes a silver chalcogenide-based material.
The first base material element and the second base material element are each an element selected from the group consisting of sulfur, selenium, and tellurium,
The solid phase change material is represented by Ag 2 S x Se 1-x , Ag 2 S x Te 1-x or Ag 2 Se x Te 1-x ,
The laminate according to claim 3, wherein x has a relationship of 0≦x≦1.
The laminate according to claim 1 or 2, wherein each of the plurality of material layers has a thickness of 10 μm or more and 5 mm or less.
The laminate according to claim 2 , wherein the diffusion suppressing layer is made of at least one of SiO2, SiN, SiON, epoxy resin, and silicone resin.
The laminate according to claim 2, wherein the diffusion suppressing layer has a thickness of 10 nm or more and is thinner than the thickest material layer among the plurality of material layers.
The plurality of material layers further includes a third material layer made of a solid phase change material including the first base material element and the second base material element,
The laminate according to claim 1 or 3, wherein the first material layer, the third material layer, and the second material layer are arranged in this order in the thickness direction of the plurality of material layers.
Other materials of the atoms contained in each material layer, which are arranged between the first material layer and the third material layer and between the third material layer and the second material layer, respectively. The laminate according to claim 8, further comprising a diffusion suppression layer that suppresses diffusion into the layer.
The plurality of material layers further includes a third material layer made of a solid phase change material including the first base material element and the second base material element,
The laminate according to claim 1 or 3, wherein the first material layer, the second material layer, and the third material layer are arranged in this order in the thickness direction of the plurality of material layers.
11. The method according to claim 10, further comprising a diffusion suppressing layer disposed between the second material layer and the third material layer and suppressing diffusion of atoms contained in each material layer to other material layers. The described laminate.