Infrared detecting element and infrared sensor having the same

Abstract

The infrared detecting element has a temperature detecting layer (22) and an infrared absorbing layer (25) which is provided separately from the temperature detecting layer (22) and absorbs infrared rays and converts them into heat. The temperature detecting layer (22) is thermally connected to the infrared absorbing layer (25), and the infrared absorbing layer (25) contains iron oxide.

Description

Technical Field

[0001] This disclosure relates to infrared detection elements and infrared sensors having the same. Background Technology

[0002] Infrared sensors for detecting infrared radiation are known. The temperature sensing layer of an infrared sensor experiences a temperature change due to infrared radiation incident from the outside, and this temperature change can be captured as a change in resistance. Therefore, to improve the performance of an infrared sensor, it is important to increase the absorption efficiency of infrared radiation absorbed by the temperature sensing layer and its surroundings. International Publication No. 2019 / 171488 discloses an infrared sensor having a radiation shield facing the back of the infrared incident surface of a calorimeter film. The spacing between the calorimeter film and the radiation shield is approximately one-quarter of the wavelength of the incident infrared radiation. This allows interference between the infrared radiation incident on the radiation shield and the infrared radiation reflected by the radiation shield, thereby enabling efficient introduction of infrared radiation into the calorimeter film. Japanese Patent Application Publication No. 2024-129503 discloses an electromagnetic wave sensor in which a thermistor film is covered by a dielectric layer. The dielectric layer functions as an electromagnetic wave absorber. Summary of the Invention

[0003] The radiation shielding device described in International Publication No. 2019 / 171488 can improve the absorption efficiency of infrared radiation in a specific narrow wavelength range, but it is difficult to improve the absorption efficiency of infrared radiation in a wide wavelength range. The dielectric layer described in Japanese Patent Application Publication No. 2024-129503 absorbs infrared radiation in a wide wavelength range, but the absorption efficiency of infrared radiation is low.

[0004] The purpose of this disclosure is to provide an infrared detection element that can improve infrared absorption efficiency over a wide wavelength range.

[0005] The infrared detection element disclosed herein includes: a temperature detection layer; and an infrared absorption layer disposed separately from the temperature detection layer, which absorbs infrared radiation and converts it into heat. The temperature detection layer and the infrared absorption layer are thermally connected, and the infrared absorption layer comprises iron oxide.

[0006] According to this disclosure, an infrared detection element that can improve the absorption efficiency of infrared light over a wide wavelength range can be provided. Attached Figure Description

[0007] Figure 1 This is a schematic side view of the infrared sensor according to the first embodiment of this disclosure.

[0008] Figure 2 yes Figure 1 A partial schematic top view.

[0009] Figure 3 yes Figure 1 Enlarged view of part A.

[0010] Figure 4 It is along Figure 3 A cross-sectional view of the BB line.

[0011] Figure 5 It is a chart showing the absorption coefficients of several substances.

[0012] Figure 6 This is a schematic side view of the infrared detection element according to the second embodiment of this disclosure.

[0013] Figure 7 This is a schematic side view of the infrared detection element according to the third embodiment of this disclosure.

[0014] Figure 8 This is a schematic side view of the infrared detection element according to the fourth embodiment of this disclosure.

[0015] Figure 9 This is a schematic side view of the infrared detection element according to the fifth embodiment of this disclosure.

[0016] Figure 10 This is a schematic side view of the infrared sensor according to the sixth embodiment of this disclosure.

[0017] Figure 11 yes Figure 10 Enlarged view of part C.

[0018] Symbol Explanation

[0019] 1: First substrate; 2: Second substrate; 11: Infrared detection element; 21: Main body; 22: Temperature detection layer; 23: Dielectric layer; 24A~24F: Electrode layers; 25: Infrared absorption layer; 34A, 34B: First and second conductive pillars; 100: Infrared sensor. Detailed Implementation

[0020] Hereinafter, embodiments of the infrared detection element and the infrared sensor equipped with the infrared detection element of the present disclosure will be described with reference to the accompanying drawings. The accompanying drawings are schematic diagrams illustrating the present disclosure, and the shapes and dimensions of the various elements may differ between the drawings. In the following description and drawings, the X and Y directions are directions parallel to the main surface 1A of the first substrate 1 and the main surface 2A of the second substrate 2. The main surfaces 1A and 2A are the surfaces of the first substrate 1 and the second substrate 2 facing each other. The X and Y directions are orthogonal to each other. The Z direction is a direction orthogonal to the X and Y directions, and is a direction perpendicular to the main surface 1A of the first substrate 1 and the main surface 2A of the second substrate 2, or the film thickness direction of the temperature detection layer 22.

[0021] Infrared sensors are primarily used as imaging elements in infrared cameras. Besides being used as night vision sights and goggles in low-light conditions, infrared cameras can also be used for temperature measurement of people or objects.

[0022] (First Embodiment)

[0023] (Overall structure)

[0024] Figure 1 This is a schematic side view of the infrared sensor 100. Figure 1 The illustrations of suspensions 31A and 31B are omitted. Five infrared detection elements 11 are arranged in the X direction, but as will be described later, the number of infrared detection elements 11 is not limited. The infrared sensor 100 has: a first substrate 1 and a second substrate 2 arranged opposite to each other; and a sidewall 3 connecting the first substrate 1 and the second substrate 2 and surrounding them in the circumferential direction. A sealed internal space 4 is formed by the first substrate 1, the second substrate 2, and the sidewall 3. A plurality of infrared detection elements 11 serving as sensing parts of the infrared sensor 100 are provided in the internal space 4. Since the internal space 4 is set to a negative pressure or even a vacuum, convection of gas in the internal space 4 is prevented or suppressed, and the thermal effects on the infrared detection elements 11 can be reduced.

[0025] The first substrate 1 is mainly composed of a silicon substrate and supports multiple infrared detection elements 11. The first substrate 1 includes circuitry such as a ROIC (Readout IC) for reading the output signals of the infrared detection elements 11, and internal wiring (not shown). Multiple pads (not shown) for input / output with the outside are formed on the outer side of the sidewall 3 of the first substrate 1. These pads are electrically connected to the circuitry via internal wiring. The second substrate 2 is also mainly composed of a silicon substrate and constitutes the input section for infrared (IR). The second substrate 2 is located on the side where the infrared (IR) to be detected is incident. The second substrate 2 allows infrared (IR) to pass through and to be incident on the infrared detection element 11. The first substrate 1 and the second substrate 2 can also be germanium substrates that allow infrared (IR) to pass through.

[0026] Figure 2 It was observed along the Z-direction. Figure 1 A partial top view also schematically shows the first wiring 41X and the second wiring 41Y. Figure 3 yes Figure 1 Enlarged view of part A, Figure 4 It is along Figure 3A cross-sectional view of the BB line. Multiple infrared detection elements 11 are arranged in an array, more specifically, configured as a two-dimensional lattice array consisting of multiple rows R extending along the X direction and multiple columns C extending along the Y direction. The temperature detection layer 22 (described later) of each infrared detection element 11 constitutes a unit or pixel in this array. Examples of the number of rows and columns in the array include 640 rows × 480 columns, 1024 rows × 768 columns, etc., but are not limited to these. The first substrate 1 has multiple first wirings 41X extending along the X direction and multiple second wirings 41Y extending along the Y direction. The multiple first wirings 41X and multiple second wirings 41Y are disposed inside the first substrate 1, electrically connected to the ROIC, and extend at different positions in the Z direction.

[0027] (Structure of infrared detection element 11)

[0028] like Figures 2-4 As shown, each infrared detection element 11 has a main body 21 and first and second suspensions 31A and 31B supporting the main body 21. The main body 21 has a generally rectangular shape when viewed from above in the Z direction. The first suspension 31A is connected near a corner 211 of the main body 21. The second suspension 31B is connected near a corner 212 diagonally opposite to the corner 211 of the main body 21. The positions of the connections between the first and second suspensions 31A and 31B and the main body 21 are not limited; for example, they may be located near the midpoints of two opposite sides 213 and 214 of the main body 21. Figure 3 As shown, the first and second suspensions 31A and 31B have a conductive layer 32 and two dielectric layers 33 sandwiching the conductive layer 32 in the Z direction. The conductive layer 32 may be formed, for example, of a metal such as titanium or a conductive nitride such as titanium nitride. The two dielectric layers 33 may be formed, for example, of the same material as the dielectric layer 23 of the main body 21 (described later). The conductive layer 32 is electrically connected to the first and second conductive struts 34A and 34B described below.

[0029] Each infrared detection element 11 has cylindrical first and second conductive supports 34A and 34B. The first conductive support 34A is electrically connected to the corresponding first wiring 41X. The second conductive support 34B is electrically connected to the corresponding second wiring 41Y. The first conductive support 34A supports the first suspension 31A and, through the first suspension 31A, supports the main body 21. The second conductive support 34B supports the second suspension 31B and, through the second suspension 31B, supports the main body 21. The first conductive support 34A is electrically connected to the conductive layer 32 of the first suspension 31A, and the second conductive support 34B is electrically connected to the conductive layer 32 of the second suspension 31B.

[0030] The main body 21 includes a temperature sensing layer 22, a dielectric layer 23, first and second electrode layers 24A and 24B, and an infrared absorption layer 25. The temperature sensing layer 22 is, for example, a square or rectangular thermistor film viewed from above in the Z direction, having an incident surface 221 opposite to the second substrate 2 where infrared light to be detected is incident, and a back surface 222 opposite to the first substrate 1. The shape of the temperature sensing layer 22 is not limited to square or rectangular; it can take any shape. The temperature sensing layer 22 may contain, for example, at least one of vanadium oxide, amorphous silicon, polycrystalline silicon, manganese-containing spinel-type crystal structure oxide, titanium oxide, and yttrium-barium-copper oxide. The temperature sensing layer 22 can replace the thermistor film, for example, a diode film such as a silicon diode film, a thermocouple film, a thermopile film, or a thermoelectric film such as lead zirconate titanate film.

[0031] The dielectric layer 23 covers at least a portion of the temperature sensing layer 22. The dielectric layer 23 may be disposed at least between the temperature sensing layer 22 and the infrared absorption layer 25 to cover the incident surface 221 of the temperature sensing layer 22, and may also cover the back surface 222. The dielectric layer 23 is formed of aluminum nitride, silicon nitride, aluminum oxide, or silicon oxide, and functions as an infrared absorber. In this embodiment, the dielectric layer 23 is disposed between the temperature sensing layer 22 and the infrared absorption layer 25, and the temperature sensing layer 22 and the infrared absorption layer 25 are not in contact. Furthermore, in this embodiment, the dielectric layer 23 is disposed between the first electrode layer 24A and the infrared absorption layer 25, and between the second electrode layer 24B and the infrared absorption layer 25, and the first and second electrode layers 24A and 24B are not in contact with the infrared absorption layer 25.

[0032] like Figure 4 As shown, the first electrode layer 24A is disposed along one edge 213 of the main body 21 and is electrically connected to the temperature detection layer 22. The second electrode layer 24B is disposed along the edge 214 opposite to the edge 213 of the main body 21 and is electrically connected to the temperature detection layer 22. The first and second electrode layers 24A and 24B are in contact with the incident surface 221 of the temperature detection layer 22, but may also be in contact with the back surface 222. The first electrode layer 24A is electrically connected to the conductive layer 32 of the first suspension 31A, and the second electrode layer 24B is electrically connected to the conductive layer 32 of the second suspension 31B. The first and second electrode layers 24A and 24B supply current in the in-plane direction (XY plane) of the temperature detection layer 22 to the temperature detection layer 22. The first and second electrode layers 24A and 24B may be formed, for example, of a metal such as titanium or a conductive nitride such as titanium nitride. In this embodiment, since the dielectric layer 23 is disposed between the temperature detection layer 22 and the infrared absorption layer 25, and the temperature detection layer 22 and the infrared absorption layer 25 are not in contact, current can flow in the temperature detection layer 22 without leaking to the infrared absorption layer 25.

[0033] The infrared sensor 100 has an infrared reflective layer 26 corresponding to each infrared detection element 11. The infrared reflective layer 26 is provided at least at a position opposite to the main body 21. A portion of the infrared light incident from the second substrate 2 passes through the main body 21 and is reflected by the infrared reflective layer 26 before incident back onto the main body 21. This improves the infrared absorption efficiency of the main body 21. The infrared reflective layer 26 can be formed of a material with high infrared reflectivity, such as gold, copper, or aluminum.

[0034] (Structure of infrared absorption layer 25)

[0035] Each infrared detection element 11 has an infrared absorption layer 25. The infrared absorption layer 25 is a film-like component that absorbs infrared radiation and converts it into heat, and is disposed separately from the temperature detection layer 22. The heat generated in the infrared absorption layer 25 is transmitted to the temperature detection layer 22 through the dielectric layer 23. That is, the temperature detection layer 22 and the infrared absorption layer 25 are thermally connected. In this embodiment, the temperature detection layer 22 and the infrared absorption layer 25 are thermally connected through the dielectric layer 23.

[0036] Infrared absorption layer 25 contains iron oxide (FeO) x More specifically, the iron oxide comprises at least one of iron oxide (II, III) and iron oxide (III). Iron oxide (II, III) (Fe3O4) is iron oxide with ferric ions at site A and ferrous ions at sites B, exhibiting an anti-spinel structure. Iron oxide (III) (Fe2O3) is iron oxide containing only ferric ions as iron ions. The infrared absorbing layer 25 may contain iron oxide (II, III) but not iron oxide (III), may contain iron oxide (III) but not iron oxide (II, III), or may contain both iron oxide (II, III) and iron oxide (III).

[0037] Figure 5 The infrared absorption coefficients of iron oxide (II, III) (Fe3O4) and iron oxide (III) (Fe2O3) are shown, as well as the infrared absorption coefficients of silicon oxide (SiO2) and silicon nitride (Si3N4), which are commonly used in the dielectric layer 23, also used as infrared absorbers. Figure 5 In the graph, the infrared absorption coefficient of iron oxide (II, III) in the wavelength region from 1 μm to 4 μm reaches the upper limit of the vertical axis (3.5 × 10⁻⁶). 6 [μm -1The above are the characteristics of silicon oxide. Iron oxide (II, III) has a high infrared absorption coefficient in the wavelength region of at least 1 μm to 20 μm, while iron oxide (III) has a high infrared absorption coefficient in the wavelength region of 15 μm to at least 20 μm. Silicon oxide has a high infrared absorption coefficient in the wavelength region of approximately 8 to 10 μm, but its infrared absorption coefficient is extremely low in other wavelength regions, exhibiting a high wavelength dependence of infrared absorption coefficient. Compared to silicon oxide, silicon nitride has a lower wavelength dependence of infrared absorption coefficient, but the range of wavelengths with high infrared absorption coefficients is limited.

[0038] Iron oxide (III), exhibiting a high infrared absorption coefficient in the wavelength region above 14 μm, is useful, for example, in an infrared sensor 100 used for measuring cryogenic objects. Generally, the wavelength of electromagnetic waves emitted by blackbody radiation increases as the blackbody temperature decreases. Therefore, when measuring objects at temperatures lower than normal, such as in measurements of extremely cold objects in space, it is sometimes desirable to detect infrared radiation in the wavelength region above 14 μm. Furthermore, the infrared absorption layer 25 containing iron oxide (II, III) is useful in applications where the detection of infrared radiation over a wide wavelength region (e.g., sensors for spectral analysis) is desired, as it can efficiently absorb infrared radiation over a wide wavelength region of at least 1 μm to 20 μm.

[0039] Iron oxides (II, III) and (III) are neither good conductors nor insulators, exhibiting conductivity close to that of semiconductors. For example, the resistivity of iron oxides (II, III) is 1 × 10⁻⁶ at 293 K. -4 The resistance is approximately Ω·m. Therefore, if iron oxide (II, III) and iron oxide (III) can be used as materials for the temperature sensing layer 22, it may be possible to omit the infrared absorption layer 25. As mentioned above, the material of the temperature sensing layer 22 requires a large change in resistance relative to temperature. The ratio of the change in resistance to the change in temperature is usually expressed by the temperature coefficient of resistance. The larger the absolute value of the temperature coefficient of resistance, the larger the ratio of the change in resistance to the change in temperature, and therefore the greater the sensitivity of the infrared sensor 100.

[0040] Table 1 shows examples of the temperature coefficient of resistance (TCR) of several materials at 300 K (near room temperature). It can be seen that iron oxide (II, III) and iron oxide (III) have TCRs that are an order of magnitude smaller than those of the material used in the temperature sensing layer 22, making them less than ideal materials for the temperature sensing layer 22. The absolute value of the TCR of the temperature sensing layer 22 at 300 K is preferably 2 or more, and more preferably 3 or more. On the other hand, while iron oxide (II, III) and iron oxide (III) have lower temperature detection capabilities, their infrared absorption efficiency is high over a wide wavelength range. Therefore, in this embodiment, the infrared absorption layer 25 and the temperature sensing layer 22 are separated, with different materials (layers) sharing the temperature detection and infrared absorption functions, thereby achieving both high temperature detection capabilities and high infrared absorption capabilities.

[0041] Table 1

[0042]

[0043] Hereinafter, other embodiments will be described, focusing on the differences from the first embodiment. The structures and effects will be omitted from the description, but in particular, the structure of the infrared absorption layer 25 is the same as in the first embodiment.

[0044] (Second Implementation)

[0045] Figure 6 This is a partial schematic side view of the infrared detection element 11 of the infrared sensor 100 according to the second embodiment. The main body 21 has a back electrode layer 24C connected to the back surface 222 of the temperature detection layer 22, and the other structures are the same as in the first embodiment. The first and second electrode layers 24A, 24B and the back electrode layer 24C supply current in the thickness direction (Z direction) of the temperature detection layer 22 to the temperature detection layer 22. Figure 6In the example shown, the infrared absorption layer 25 is disposed on the infrared incident side as viewed from the temperature detection layer 22. However, as a variation, although not shown in the figure, the infrared absorption layer 25 can also be disposed on the side opposite to the incident side of the temperature detection layer 22, and the back electrode layer 24C can be disposed between the temperature detection layer 22 and the infrared absorption layer 25. In this case, a dielectric layer 23 can also be disposed between the back electrode layer 24C and the infrared absorption layer 25, so that the back electrode layer 24C is not in contact with the infrared absorption layer 25. Alternatively, the back electrode layer 24C can also be in contact with the infrared absorption layer 25. When the back electrode layer 24C is in contact with the infrared absorption layer 25, a portion of the current may flow through the infrared absorption layer 25 (leaking into the infrared absorption layer 25). However, even in this case, the current flowing through the temperature detection layer 22 is hardly affected, so there is almost no impact on the detection accuracy of the temperature change of the temperature detection layer 22. That is, one electrode layer can be connected to one of the incident surface 221 and the back surface 222 (back surface 222 in this embodiment), and two electrode layers can be connected to the other of the incident surface 221 and the back surface 222 (incident surface 221 in this embodiment), and the one electrode layer can be disposed between the temperature detection layer 22 and the infrared absorption layer 25. The one electrode layer and the two electrode layers supply current in the thickness direction (Z direction) of the temperature detection layer 22 to the temperature detection layer 22.

[0046] (Third implementation)

[0047] Figure 7 This is a partial schematic side view of the infrared detection element 11 of the infrared sensor 100 according to the third embodiment. The main body 21 has: an incident-side electrode layer 24D connected to the incident surface 221 of the temperature detection layer 22; and two back electrode layers 24E and 24F connected to the back surface 222 of the temperature detection layer 22. The incident-side electrode layer 24D is disposed on almost the entire surface of the incident surface 221 of the temperature detection layer 22. The incident-side electrode layer 24D is in contact with the infrared absorption layer 25. The two back electrode layers 24E and 24F correspond to the first and second electrode layers 24A and 24B of the first embodiment. The incident-side electrode layer 24D and the two back electrode layers 24E and 24F supply current in the thickness direction (Z direction) of the temperature detection layer 22 to the temperature detection layer 22. The current flows through the incident-side electrode layer 24D, the two back electrode layers 24E and 24F, and the temperature detection layer 22. A portion of the current may flow through the infrared absorption layer 25 (leaking into the infrared absorption layer 25), but even in this case, the current flowing through the temperature detection layer 22 is almost unaffected, so it has almost no impact on the detection accuracy of temperature changes in the temperature detection layer 22. Figure 7The embodiment shown omits the dielectric layer 23 between the temperature detection layer 22 and the infrared absorption layer 25 in the first and second embodiments, thus simplifying the manufacturing process of the infrared sensor 100. Furthermore, in Figure 7 In the example shown, the incident electrode layer 24D is in contact with the infrared absorption layer 25. However, as a variation, although the illustration is omitted, a dielectric layer 23 can be provided between the incident electrode layer 24D and the infrared absorption layer 25, so that the incident electrode layer 24D is not in contact with the infrared absorption layer 25. That is, one electrode layer can be connected to one of the incident surface 221 and the back surface 222 (in this embodiment, the incident surface 221), and two electrode layers can be connected to the other of the incident surface 221 and the back surface 222 (in this embodiment, the back surface 222), and this one electrode layer can be disposed between the temperature detection layer 22 and the infrared absorption layer 25. One electrode layer and two electrode layers supply current in the thickness direction (Z direction) of the temperature detection layer 22 to the temperature detection layer 22.

[0048] (Fourth implementation)

[0049] Figure 8 This is a partial schematic side view of the infrared detection element 11 of the infrared sensor 100 according to the fourth embodiment. In this embodiment, the dielectric layer 23 between the temperature detection layer 22 and the infrared absorption layer 25 in the first embodiment is omitted, and the other structures are the same as in the first embodiment. The temperature detection layer 22 is in contact with the infrared absorption layer 25. The first and second electrode layers 24A and 24B supply current in the in-plane direction (XY plane) of the temperature detection layer 22 to the temperature detection layer 22. A portion of the current flows through the infrared absorption layer 25, thereby bypassing the temperature detection layer 22. However, since the conductivity of the temperature detection layer 22 is higher than that of the infrared absorption layer 25, the current flowing through the infrared absorption layer 25 (bypassing the temperature detection layer 22) is limited. Therefore, in this embodiment, the detection accuracy of the temperature change (resistance change) of the temperature detection layer 22 is not significantly affected.

[0050] In the illustrated configuration, the infrared absorption layer 25 is separated from the first and second electrode layers 24A and 24B, but it can also be connected to the first and second electrode layers 24A and 24B. Furthermore, the first and second electrode layers 24A and 24B are connected to the incident surface 221 of the temperature detection layer 22, but they can also be connected to the back surface 222 of the temperature detection layer 22. In this embodiment, the dielectric layer 23 between the temperature detection layer 22 and the infrared absorption layer 25 in the first embodiment can also be omitted, thus simplifying the manufacturing process of the infrared sensor 100.

[0051] (Fifth implementation)

[0052] Figure 9 This is a partial schematic side view of the infrared detection element 11 of the infrared sensor 100 according to the fifth embodiment. The main body 21 has: an arm 27 extending from the surface 23A of the dielectric layer 23 toward the second substrate 2 in the Z direction; and a plate-shaped portion 28 connected to the end portion 27A of the arm 27 on the second substrate 2 side. The plate-shaped portion 28 is located closer to the infrared incident side than the dielectric layer 23. The arm 27 and the plate-shaped portion 28 are made of dielectric material, formed of aluminum nitride, silicon nitride, aluminum oxide, or silicon oxide, or may be formed of the same material as the dielectric layer 23.

[0053] An infrared absorption layer 25 is disposed on the surface 28A of the plate-shaped portion 28 facing the second substrate 2. The infrared absorption layer 25 may be disposed on the entire surface 28A of the plate-shaped portion 28, or only on a portion of the surface 28A. Incident infrared radiation is absorbed by the infrared absorption layer 25, and the heat generated in the infrared absorption layer 25 propagates to the temperature detection layer 22 through the plate-shaped portion 28, the arm portion 27, and the dielectric layer 23. That is, in this embodiment, the temperature detection layer 22 and the infrared absorption layer 25 are thermally connected via the plate-shaped portion 28, the arm portion 27, and the dielectric layer 23. An infrared reflective layer 26 is disposed on the surface 23A of the dielectric layer 23 facing the second substrate 2. When viewed from the Z direction, the plate-shaped portion 28 may also be disposed in the area overlapping with the first and second suspensions 31A and 31B, thus ensuring a wider planar area than the dielectric layer 23. Therefore, the planar area of ​​the infrared absorber can be larger than in the first embodiment, further improving infrared absorption performance. The plate-shaped portion 28 itself also functions as an infrared absorber, thus further improving infrared absorption performance.

[0054] (Sixth implementation)

[0055] Figure 10 This is a schematic side view of the infrared sensor 100 according to the sixth embodiment. Figure 11 yes Figure 10 Enlarged view of part C. The infrared sensor 100 has a plurality of first electrical connection members 42X and a plurality of second electrical connection members 42Y. The first and second electrical connection members 42X and 42Y are cylindrical conductors extending along the Z direction between the first substrate 1 and the second substrate 2 and electrically connected to the ROIC. A plurality of first wirings 41X and a plurality of second wirings 41Y are disposed on the second substrate 2, and the infrared detection element 11 is supported by the second substrate 2. The plurality of first wirings 41X are respectively connected to the corresponding first electrical connection members 42X, and the plurality of second wirings 41Y are respectively connected to the corresponding second electrical connection members 42Y (in Figure 10In the illustration, only one of the multiple second electrical connection members 42Y is shown, and only a portion of the second electrical connection member 42Y in the Z direction is shown. The structure of the main body 21, the first and second suspensions 31A, 31B, the first and second conductive struts 34A, 34B, and the first and second wirings 41X, 41Y are the same as in the first embodiment.

[0056] In this embodiment, the main body 21 is supported on the second substrate 2 by the first and second conductive pillars 34A and 34B. Therefore, a longer heat transfer path from local heat sources such as the ROIC disposed on the first substrate 1 can be ensured compared to the first embodiment, and the influence of heat from local heat sources on the temperature sensing layer 22 can be suppressed. In this embodiment, a plurality of first wirings 41X and a plurality of second wirings 41Y are disposed on the second substrate 2, and the temperature sensing layer 22 is electrically connected to the corresponding first wirings 41X and second wirings 41Y via the first and second conductive pillars 34A and 34B. In a modified example, for example, one or both of the plurality of first wirings 41X and the plurality of second wirings 41Y may be disposed between the infrared detection element 11 and the first substrate 1, and the temperature sensing layer 22 may be electrically connected to these wirings via other conductive pillars. In this case, the support pillars used to support the main body 21 on the second substrate 2 can also be non-conductive as long as they do not bear the electrical connection between the plurality of first wirings 41X and the temperature sensing layer 22, or the plurality of second wirings 41Y and the temperature sensing layer 22. This embodiment can also be combined with embodiments 2 to 5. That is, the structure of the main body 21 can also be the same as that of the main body 21 in embodiments 2 to 5.

[0057] The embodiments of the infrared sensor disclosed herein have been described above, but the infrared sensor disclosed herein is not limited to these embodiments. In each of the above embodiments, the infrared absorption layer 25 is only provided on the infrared incident side as viewed from the temperature detection layer 22, but the infrared absorption layer may also be formed only on the side opposite to the incident side of the temperature detection layer 22, or it may be provided on both sides. The infrared absorption layer provided on the side opposite to the incident side absorbs the infrared rays that have passed through the temperature detection layer 22, and the heat generated in the infrared absorption layer is transmitted to the temperature detection layer 22. Therefore, similar to the infrared absorption layer 25 formed on the incident side, the absorption efficiency of infrared rays can be improved. When infrared absorption layers are formed on both the incident side and the side opposite to the incident side, the infrared absorption layers on both sides may have the same composition or different compositions. For example, the infrared absorption layer 25 on the incident side may only contain iron oxide (II, III), while the infrared absorption layer on the side opposite to the incident side may simultaneously contain iron oxide (II, III) and iron oxide (III). Therefore, it is possible to improve the absorption efficiency of infrared radiation in the wavelength range of at least 1 μm to 20 μm, and further improve the absorption efficiency of infrared radiation with wavelengths generally exceeding 15 μm.

Claims

1. An infrared detection element, wherein, have: Temperature sensing layer; as well as A separate infrared absorption layer that absorbs infrared light and converts it into heat. The temperature detection layer is thermally connected to the infrared absorption layer. The infrared absorbing layer contains iron oxide.

2. The infrared detection element as described in claim 1, wherein, The iron oxide comprises at least one of iron oxide (II, III) and iron oxide (III).

3. The infrared detection element as described in claim 1, wherein, At least a portion of the iron oxide has an anti-spinel structure.

4. The infrared detection element as described in any one of claims 1 to 3, wherein, The absolute value of the temperature coefficient of resistance of the temperature sensing layer at 300K is greater than 2.

5. The infrared detection element as described in any one of claims 1 to 3, wherein, The absolute value of the temperature coefficient of resistance of the temperature sensing layer at 300K is greater than 3.

6. The infrared detection element as described in any one of claims 1 to 3, wherein, The temperature sensing layer comprises at least one of vanadium oxide, amorphous silicon, polycrystalline silicon, manganese-containing spinel-type crystal structure oxide, titanium oxide, and yttrium-barium-copper oxide.

7. The infrared detection element as described in any one of claims 1 to 3, wherein, It has a dielectric layer disposed between the temperature sensing layer and the infrared absorption layer.

8. The infrared detection element as described in any one of claims 1 to 3, wherein, have: An electrode layer connected to one of the incident surface of the infrared radiation to be detected and the back surface of the incident surface of the temperature detection layer; and Two electrode layers connected to the other side of the incident surface and the back surface. The one electrode layer and the two electrode layers supply current in the thickness direction of the temperature sensing layer to the temperature sensing layer. The electrode layer is disposed between the temperature detection layer and the infrared absorption layer.

9. The infrared detection element as described in any one of claims 1 to 3, wherein, It has two electrode layers that are electrically connected to the temperature sensing layer. The two electrode layers supply the temperature sensing layer with an in-plane current. The temperature sensing layer is in contact with the infrared absorption layer, and the conductivity of the temperature sensing layer is higher than that of the infrared absorption layer.

10. The infrared detection element as described in any one of claims 1 to 3, wherein, have: The main body includes the temperature detection layer and the infrared absorption layer; A substrate located on the side of the main body where the infrared light to be detected is incident; as well as A support for supporting the main body on the substrate.

11. An infrared sensor, wherein, It has an infrared detection element as described in any one of claims 1 to 3.

12. An infrared sensor, wherein, Equipped with a plurality of infrared detection elements as described in any one of claims 1 to 3, The infrared detection elements are arranged in an array.

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