Infrared detection element and infrared sensor equipped therewith

Abstract

It enhances the absorption efficiency of infrared rays across a wide wavelength range. [Solution] The infrared sensing element has a temperature sensing layer 22 and an infrared absorbing layer 25 provided separately from the temperature sensing layer 22, which absorbs infrared rays and converts them into heat. The temperature sensing layer 22 and the infrared absorbing layer 25 are thermally connected, and the infrared absorbing layer 25 contains iron oxide.

Description

Technical Field

[0001] The present disclosure relates to an infrared detection element and an infrared sensor including the same.

Background Art

[0002] Infrared sensors for detecting infrared rays are known. The temperature detection layer of an infrared sensor causes a temperature change due to infrared rays incident from the outside, and the temperature change of the temperature detection layer is taken out as a resistance change. Therefore, in order to improve the performance of an infrared sensor, it is important to increase the absorption efficiency of infrared rays absorbed by the temperature detection layer or around the temperature detection layer. Patent Document 1 describes an infrared sensor provided with a radiation shield facing the back surface of the infrared incident surface of a bolometer film. The distance between the bolometer film and the radiation shield is set to about 1 / 4 of the wavelength of the incident infrared rays. By this, the infrared rays incident on the radiation shield and the infrared rays reflected by the radiation shield are made to interfere with each other, and the infrared rays can be efficiently taken into the bolometer film. Patent Document 2 describes an electromagnetic wave sensor in which a thermistor film is covered with a dielectric layer. The dielectric layer functions as an electromagnetic wave absorber.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] The radiation shield described in Patent Document 1 can increase the absorption efficiency of infrared rays in a specific narrow wavelength range, but it is difficult to increase the absorption efficiency of infrared rays in a wide wavelength range. The dielectric layer described in Patent Document 2 absorbs infrared rays in a wide wavelength range, but the absorption efficiency of infrared rays is low.

[0005] The purpose of this disclosure is to provide an infrared detection element that can improve the absorption efficiency of infrared rays over a wide wavelength range. [Means for solving the problem]

[0006] The infrared sensing element of this disclosure comprises a temperature sensing layer and an infrared absorbing layer provided separately from the temperature sensing layer, which absorbs infrared rays and converts them into heat. The temperature sensing layer and the infrared absorbing layer are thermally connected, and the infrared absorbing layer contains iron oxide. [Effects of the Invention]

[0007] According to this disclosure, it is possible to provide an infrared detection element that can improve the absorption efficiency of infrared rays over a wide wavelength range. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic side view of an infrared sensor according to the first embodiment of the present disclosure. [Figure 2] This is a partial schematic plan view of Figure 1. [Figure 3] This is an enlarged view of section A in Figure 1. [Figure 4] This is a cross-sectional view along line BB in Figure 3. [Figure 5] This is a graph showing the absorption coefficients of several substances. [Figure 6] This is a schematic side view of an infrared detection element according to a second embodiment of the present disclosure. [Figure 7] This is a schematic side view of an infrared detection element according to a third embodiment of the present disclosure. [Figure 8] This is a schematic side view of an infrared detection element according to the fourth embodiment of this disclosure. [Figure 9] This is a schematic side view of an infrared detection element according to the fifth embodiment of this disclosure. [Figure 10] This is a schematic side view of an infrared sensor according to the sixth embodiment of the present disclosure. [Figure 11] This is an enlarged view of section C in Figure 10. [Modes for carrying out the invention]

[0009] Embodiments of the infrared sensing element and the infrared sensor equipped with the infrared sensing element of this disclosure will be described below with reference to the drawings. The drawings are schematic diagrams illustrating this disclosure, and the shapes and dimensions of elements may not be consistent between drawings. In the following description and drawings, the X and Y directions are 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 mutually opposing surfaces of the first substrate 1 and the second substrate 2. The X and Y directions are orthogonal to each other. The Z direction is orthogonal to the X and Y directions and is perpendicular to the main surface 1A of the first substrate 1 and the main surface 2A of the second substrate 2, or the direction of the film thickness of the temperature sensing layer 22.

[0010] Infrared sensors are primarily used as image sensors in infrared cameras. Infrared cameras can be used as night vision scopes and goggles in dark places, as well as for measuring the temperature of people and objects.

[0011] (First embodiment) (Overall structure) Figure 1 is a schematic side view of the infrared sensor 100. Suspensions 31A and 31B are not shown in Figure 1. Five infrared detection elements 11 are arranged in the X direction, but the number of infrared detection elements 11 is not limited, as will be described later. The infrared sensor 100 has a first substrate 1 and a second substrate 2 arranged facing each other, and a side wall 3 that connects the first substrate 1 and the second substrate 2 and extends circumferentially. The first substrate 1, the second substrate 2 and the side wall 3 form a sealed internal space 4. Multiple infrared detection elements 11, which function as the sensing part of the infrared sensor 100, are provided in the internal space 4. Since the internal space 4 is under negative pressure or a vacuum, gas convection in the internal space 4 is prevented or suppressed, and the thermal influence on the infrared detection elements 11 can be reduced.

[0012] The first substrate 1 is mainly made of a silicon substrate and supports a plurality of infrared detection elements 11. The first substrate 1 includes an electric circuit such as a ROIC (Readout IC) for reading out the output signal of the infrared detection element 11 and internal wirings (both not shown). On the outside of the side wall 3 of the first substrate 1, a plurality of pads (not shown) for input / output with the outside are formed. The pads are electrically connected to the electric circuit by the internal wirings. The second substrate 2 is also mainly made of a silicon substrate and constitutes an input portion of infrared IR. The second substrate 2 is the substrate on the side where the infrared IR to be detected is incident. The second substrate 2 transmits the infrared IR and makes the infrared IR incident on the infrared detection element 11. The first substrate 1 and the second substrate 2 may be germanium substrates that transmit infrared rays.

[0013] FIG. 2 is a partial plan view of FIG. 1 viewed in the Z direction, and also schematically shows the first wiring 41X and the second wiring 41Y. FIG. 3 is an enlarged view of part A of FIG. 1, and FIG. 4 is a cross-sectional view taken along line B-B of FIG. 3. The plurality of infrared detection elements 11 are arranged in an array, and more specifically, form a two-dimensional grid-like array composed of a plurality of rows R extending in the X direction and a plurality of columns C extending in the Y direction. The temperature detection layer 22 (described later) of each infrared detection element 11 constitutes one cell or pixel in this array. Examples of the number of rows and columns of the array include 640 rows × 480 columns, 1024 rows × 768 columns, etc., but are not limited thereto. The first substrate 1 has a plurality of first wirings 41X extending in the X direction and a plurality of second wirings 41Y extending in the Y direction. The plurality of first wirings 41X and the plurality of second wirings 41Y are provided inside the first substrate 1, are electrically connected to the ROIC, and extend at different positions from each other in the Z direction.

[0014] (Configuration of Infrared Detection Element 11) As shown in FIGS. 2 to 4, each infrared detection element 11 has a main body portion 21, and first and second suspensions 31A and 31B that support the main body portion 21. The main body portion 21 has a generally rectangular shape when viewed in the Z direction. The first suspension 31A is connected near one corner portion 211 of the main body portion 21, and the second suspension 31B is connected near a corner portion 212 that is diagonally located with respect to the corner portion 211 of the main body portion 21. The positions of the connection portions between the first and second suspensions 31A and 31B and the main body portion 21 are not limited, and for example, they may be near the midpoints of two opposing sides 213 and 214 of the main body portion 21. As shown in FIG. 3, the first and second suspensions 31A and 31B have a conductive layer 32 and two dielectric layers 33 that sandwich the conductive layer 32 in the Z direction. The conductive layer 32 can be formed of, for example, a metal such as titanium or a conductive nitride such as titanium nitride. The two dielectric layers 33 can be formed of, for example, the same material as the dielectric layer 23 (described later) of the main body portion 21. The conductive layer 32 is electrically connected to first and second conductive supports 34A and 34B described below.

[0015] Each infrared detection element 11 has cylindrical first and second conductive supports 34A and 34B. The first conductive support 34A is electrically connected to a corresponding first wiring 41X, and the second conductive support 34B is electrically connected to a corresponding second wiring 41Y. The first conductive support 34A supports the first suspension 31A and supports the main body portion 21 via the first suspension 31A. The second conductive support 34B supports the second suspension 31B and supports the main body portion 21 via the second suspension 31B. 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.

[0016] 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 thermistor film that is square or rectangular in shape when viewed in the Z direction, and has an incident surface 221 that faces the second substrate 2 and is incident on the infrared radiation to be detected, and a back surface 222 that faces the first substrate 1. The shape of the temperature sensing layer 22 is not limited to square or rectangular, and can take any shape. The temperature sensing layer 22 includes, for example, at least one of vanadium oxide, amorphous silicon, polycrystalline silicon, an oxide with a spinel-type crystal structure containing manganese, titanium oxide, and yttrium-barium-copper oxide. The temperature sensing layer 22 may be replaced with, for example, a diode film such as a silicon diode film, a thermocouple film, a thermopile film, or a pyroelectric film such as a lead zirconate titanate film.

[0017] The dielectric layer 23 covers at least a portion of the temperature sensing layer 22. The dielectric layer 23 is provided at least between the temperature sensing layer 22 and the infrared absorption layer 25 so as to cover the incident surface 221 of the temperature sensing layer 22, and further so as to 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 provided 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. Also in this embodiment, the dielectric layer 23 is provided 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.

[0018] As shown in Figure 4, the first electrode layer 24A is provided along one side 213 of the main body 21 and is electrically connected to the temperature sensing layer 22. The second electrode layer 24B is provided along the side 214 of the main body 21 opposite to side 213 and is electrically connected to the temperature sensing layer 22. The first and second electrode layers 24A and 24B are in contact with the incident surface 221 of the temperature sensing 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 to the temperature sensing layer 22 in the in-plane direction (XY plane) of the temperature sensing layer 22. The first and second electrode layers 24A and 24B can be formed from, for example, a metal such as titanium or a conductive nitride such as titanium nitride. In this embodiment, the dielectric layer 23 is provided 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, so current can be passed to the temperature sensing layer 22 without leakage to the infrared absorption layer 25.

[0019] The infrared sensor 100 has an infrared reflective layer 26 provided corresponding to each infrared detection element 11. The infrared reflective layer 26 is provided at least in a position facing the main body 21. A portion of the infrared radiation incident from the second substrate 2 passes through the main body 21, is reflected by the infrared reflective layer 26, and then incident on the main body 21. This increases the efficiency of infrared absorption by the main body 21. The infrared reflective layer 26 can be made of a material that has a high reflectivity to infrared radiation, such as gold, copper, or aluminum.

[0020] (Composition of the infrared absorption layer 25) Each infrared sensing element 11 has an infrared absorbing layer 25. The infrared absorbing layer 25 is a film-like material that absorbs infrared rays and converts them into heat, and is provided separately from the temperature sensing layer 22. The heat generated in the infrared absorbing layer 25 propagates to the temperature sensing layer 22 through the dielectric layer 23. In other words, the temperature sensing layer 22 and the infrared absorbing layer 25 are thermally connected, and in this embodiment, the temperature sensing layer 22 and the infrared absorbing layer 25 are thermally connected via the dielectric layer 23.

[0021] The infrared absorbing layer 25 is made of iron oxide (FeO x ) contains. More specifically, iron oxide contains at least one of iron(II,III) oxide and iron(III) oxide. Iron(II,III) oxide (Fe3O4) is an iron oxide with a trivalent iron ion at site A and divalent and trivalent iron ions at site B, and has an inverse spinel structure. Iron(III) oxide (Fe2O3) is an iron oxide that contains only trivalent iron ions as iron ions. The infrared absorbing layer 25 may contain iron(II,III) oxide but not iron(III) oxide, may contain iron(III) oxide but not iron(II,III) oxide, or may contain both iron(II,III) oxide and iron(III) oxide.

[0022] Figure 5 shows the infrared absorption coefficients of iron(II,III) oxide (Fe3O4) and iron(III) oxide (Fe2O3), and the infrared absorption coefficients of silicon oxide (SiO2) and silicon nitride (Si3O4), which are commonly used in dielectric layers 23 that also function as infrared absorbers. In Figure 5, the infrared absorption coefficient of iron(II,III) oxide in the wavelength range of 1 μm to 4 μm is shown as the upper limit of the vertical axis of the graph (3.5 × 10⁻⁶). 6 [μm -1 The above is true. Iron(II, III) oxides have high infrared absorption coefficients in the wavelength range of at least 1 μm to 20 μm, and iron(III) oxide has a high infrared absorption coefficient in the wavelength range of 15 μm to at least 20 μm. Silicon oxide has a high infrared absorption coefficient in the wavelength range of about 8 to 10 μm, but its infrared absorption coefficient is extremely low in other wavelength ranges, and its infrared absorption coefficient is highly wavelength-dependent. Silicon nitride has lower wavelength dependence of infrared absorption coefficient compared to silicon oxide, but the wavelength range in which its infrared absorption coefficient is high is limited.

[0023] Iron(III) oxide, which exhibits a high infrared absorption coefficient in the wavelength range of 14 μm or more, is useful, for example, in an infrared sensor 100 for measuring low-temperature objects. Generally, the wavelength of electromagnetic waves emitted by blackbody radiation increases as the temperature of the blackbody decreases. Therefore, when measuring objects at temperatures lower than room temperature, for example, when measuring extremely cold objects in space, it is sometimes desirable to detect infrared radiation in the wavelength range of 14 μm or more. Furthermore, since the infrared absorption layer 25 containing iron(II,III) oxide can efficiently absorb infrared radiation in a wide wavelength range of at least 1 μm to 20 μm, it is useful in applications where detection of infrared radiation in a wide wavelength range is desired, such as sensors used for spectroscopic analysis.

[0024] Iron(II,III) oxide and iron(III) oxide are neither good conductors nor insulators, but they have conductivity close to that of semiconductors. For example, the resistivity of iron(II,III) oxide is 1 × 10⁻¹⁶ at 293K. -4 It is approximately Ω·m. Therefore, if iron(II,III) oxide and iron(III) oxide can be used as the material for the temperature sensing layer 22, it may be possible to omit the infrared absorption layer 25. As mentioned above, the material for the temperature sensing layer 22 is required to have a large change in resistance with respect to temperature changes. The rate of change in resistance with respect to temperature changes is generally expressed by the temperature coefficient of resistance. The larger the absolute value of the temperature coefficient of resistance, the larger the rate of change in resistance with respect to temperature changes, and therefore the greater the sensitivity of the infrared sensor 100.

[0025] Table 1 shows examples of numerical values ​​for the temperature coefficient of resistance of several materials at 300K (around room temperature). From this, it can be seen that iron(II, III) oxide and iron(III) oxide have a temperature coefficient of resistance that is about an order of magnitude smaller than the material for the temperature sensing layer 22 described above, and are therefore unsuitable as materials for the temperature sensing layer 22. The absolute value of the temperature coefficient of resistance of the temperature sensing layer 22 at 300K is preferably 2 or more, and more preferably 3 or more. On the other hand, iron(II, III) oxide and iron(III) oxide have low temperature sensing capabilities, but high infrared absorption efficiency over a wide wavelength range. For this reason, in this embodiment, an infrared absorption layer 25 is provided separately from the temperature sensing layer 22, and the temperature sensing function and infrared absorption function are shared by different materials (layers), thereby achieving both high temperature sensing functionality and high infrared absorption functionality.

[0026] [Table 1]

[0027] The following describes other embodiments, focusing on the differences from the first embodiment. The configurations and effects that are not described, particularly the configuration of the infrared absorption layer 25, are the same as in the first embodiment.

[0028] (Second embodiment) Figure 6 is a schematic side view of a portion 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 configurations are the same as in the first embodiment. The first and second electrode layers 24A, 24B and the back electrode layer 24C supply current to the temperature detection layer 22 in the thickness direction (Z direction) of the temperature detection layer 22. In the example shown in Figure 6, the infrared absorption layer 25 is provided on the infrared incident side when viewed from the temperature detection layer 22, but as a modification, although not shown in the figure, the infrared absorption layer 25 may be provided on the opposite side from the incident side of the temperature detection layer 22, and the back electrode layer 24C may be provided between the temperature detection layer 22 and the infrared absorption layer 25. In this case, the dielectric layer 23 may be provided between the back electrode layer 24C and the infrared absorption layer 25 so that the back electrode layer 24C does not come into contact with the infrared absorption layer 25, or the back electrode layer 24C may come into contact with the infrared absorption layer 25. When the back electrode layer 24C is in contact with the infrared absorption layer 25, some of the current may flow through the infrared absorption layer 25 (leak into the infrared absorption layer 25). However, even in this case, the current flowing through the temperature sensing layer 22 is hardly affected, and therefore the accuracy of temperature change detection in the temperature sensing layer 22 is hardly affected. In other words, one electrode layer may be connected to one of the incident surface 221 and the back surface 222 (the back surface 222 in this embodiment), and two electrode layers may be connected to the other of the incident surface 221 and the back surface 222 (the incident surface 221 in this embodiment), with the one electrode layer being provided between the temperature sensing layer 22 and the infrared absorption layer 25. The one electrode layer and the two electrode layers supply current to the temperature sensing layer 22 in the film thickness direction (Z direction) of the temperature sensing layer 22.

[0029] (Third embodiment) Figure 7 is a schematic side view of a portion of the infrared sensing element 11 of the infrared sensor 100 according to the third embodiment. The main body 21 has one incident electrode layer 24D connected to the incident surface 221 of the temperature sensing layer 22, and two back electrode layers 24E and 24F connected to the back surface 222 of the temperature sensing layer 22. The incident electrode layer 24D is provided over almost the entire incident surface 221 of the temperature sensing layer 22. The incident 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 electrode layer 24D and the two back electrode layers 24E and 24F supply a current to the temperature sensing layer 22 in the film thickness direction (Z direction) of the temperature sensing layer 22. The current flows through the incident electrode layer 24D, the two back electrode layers 24E and 24F, and the temperature sensing layer 22. Although some of the current may flow through the infrared absorption layer 25 (leak into the infrared absorption layer 25), the current flowing through the temperature sensing layer 22 is hardly affected in this case, so the accuracy of temperature change detection in the temperature sensing layer 22 is hardly affected. In this embodiment shown in Figure 7, the dielectric layer 23 between the temperature sensing layer 22 and the infrared absorption layer 25 as in the first and second embodiments can be omitted, thus simplifying the manufacturing process of the infrared sensor 100. Also, in the example shown in Figure 7, the incident electrode layer 24D is in contact with the infrared absorption layer 25, but as a modification, although not shown in the figure, the dielectric layer 23 may be provided between the incident electrode layer 24D and the infrared absorption layer 25 so that the incident electrode layer 24D does not come into contact with the infrared absorption layer 25. In other words, one electrode layer may 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 may be connected to the other of the incident surface 221 and the back surface 222 (in this embodiment, the back surface 222), and the one electrode layer may be provided between the temperature sensing layer 22 and the infrared absorption layer 25. The one electrode layer and the two electrode layers supply a current to the temperature sensing layer 22 in the direction of the thickness of the temperature sensing layer 22 (Z direction).

[0030] (Fourth embodiment) Figure 8 is a schematic side view of a portion 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 configurations 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 to the temperature detection layer 22 in the in-plane direction (XY plane) of the temperature detection layer 22. A portion of the current flows through the infrared absorption layer 25 and bypasses 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. For this reason, even in this embodiment, there is no significant impact on the detection accuracy of temperature changes (resistance changes) in the temperature detection layer 22.

[0031] In the illustrated configuration, the infrared absorption layer 25 is separated from the first and second electrode layers 24A and 24B, but it may be in contact with the first and second electrode layers 24A and 24B. Also, the first and second electrode layers 24A and 24B are connected to the incident surface 221 of the temperature sensing layer 22, but they may also be connected to the back surface 222 of the temperature sensing layer 22. In this embodiment as well, the dielectric layer 23 between the temperature sensing layer 22 and the infrared absorption layer 25 in the first embodiment can be omitted, thus simplifying the manufacturing process of the infrared sensor 100.

[0032] (Fifth embodiment) Figure 9 is a schematic side view of a portion of the infrared detection element 11 of the infrared sensor 100 according to the fifth embodiment. The main body 21 has an arm portion 27 extending in the Z direction toward the second substrate 2 from the surface 23A of the dielectric layer 23 facing the second substrate 2, and a plate-like portion 28 connected to the end 27A of the arm portion 27 on the second substrate 2 side. The plate-like portion 28 is located on the infrared incident side of the dielectric layer 23. The arm portion 27 and the plate-like portion 28 are made of a dielectric material, and may be formed from aluminum nitride, silicon nitride, aluminum oxide, or silicon oxide, and may be made from the same material as the dielectric layer 23.

[0033] The infrared absorption layer 25 is provided on the surface 28A of the plate-shaped portion 28 facing the second substrate 2. The infrared absorption layer 25 can be provided over the entire surface 28A of the plate-shaped portion 28, or it may be provided only on a part of the surface 28A. Incident infrared rays are absorbed by the infrared absorption layer 25, and the heat generated in the infrared absorption layer 25 propagates to the temperature sensing layer 22 through the plate-shaped portion 28, the arm portion 27, and the dielectric layer 23. In other words, in this embodiment, the temperature sensing 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. The infrared reflection layer 26 is provided on the surface 23A of the dielectric layer 23 facing the second substrate 2. Since the plate-shaped portion 28 can also be installed in the region overlapping with the first and second suspensions 31A and 31B when viewed in the Z direction, a larger planar area than the dielectric layer 23 can be secured. Therefore, the planar area of ​​the infrared absorber can be made larger than in the first embodiment, and the infrared absorption performance can be further improved. Since the plate-shaped portion 28 itself also functions as an infrared absorber, the infrared absorption performance can be further enhanced.

[0034] (Sixth embodiment) Figure 10 is a schematic side view of the infrared sensor 100 according to the sixth embodiment, and Figure 11 is an enlarged view of section C in Figure 10. 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 that extend in the Z direction between the first substrate 1 and the second substrate 2 and are electrically connected to the ROIC. A plurality of first wirings 41X and a plurality of second wirings 41Y are provided on the second substrate 2, and the infrared detection element 11 is supported on the second substrate 2. Each of the plurality of first wirings 41X is connected to the corresponding first electrical connection member 42X, and each of the plurality of second wirings 41Y is connected to the corresponding second electrical connection member 42Y (in Figure 10, only one of the plurality of second electrical connection members 42Y is shown, and for the illustrated second electrical connection member 42Y, only a portion in the Z direction is shown). The configuration of the main body 21, the first and second suspensions 31A, 31B, the first and second conductive support columns 34A, 34B, and the first and second wiring 41X, 41Y is the same as in the first embodiment.

[0035] In this embodiment, the main body 21 is supported on the second substrate 2 by first and second conductive support columns 34A and 34B. Therefore, the heat transfer path from a local heat source such as an ROIC provided on the first substrate 1 can be made longer than in the first embodiment, and the influence of heat from the local heat source 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 provided 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 support columns 34A and 34B. In a modified example, for example, one or both of the plurality of first wirings 41X and a plurality of second wirings 41Y may be provided between the infrared detection element 11 and the first substrate 1, and the temperature sensing layer 22 and these wirings may be electrically connected via another conductive support column. In this case, the support columns that support the main body 21 on the second substrate 2 may be non-conductive, as long as they are not responsible for the electrical connection between the multiple first wirings 41X and the temperature sensing layer 22, or the electrical connection between the multiple second wirings 41Y and the temperature sensing layer 22. This embodiment can also be combined with the second to fifth embodiments. That is, the configuration of the main body 21 may be the same as the main body 21 of the second to fifth embodiments.

[0036] Although embodiments of the infrared sensor of this disclosure have been described above, the infrared sensor of this disclosure is not limited to these embodiments. In each of the embodiments described above, the infrared absorption layer 25 is provided only on the infrared incident side when viewed from the temperature sensing layer 22, but the infrared absorption layer may be formed only on the side opposite to the incident side of the temperature sensing layer 22, or it may be provided on both sides. The infrared absorption layer provided on the side opposite to the incident side absorbs infrared rays that have passed through the temperature sensing layer 22, and the heat generated in the infrared absorption layer is propagated to the temperature sensing layer 22, so the infrared absorption efficiency can be increased, similar to the infrared absorption layer 25 formed on the incident side. 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 may have different compositions. For example, the infrared absorption layer 25 on the incident side may contain only iron(II,III) oxide, and the infrared absorption layer on the side opposite to the incident side may contain both iron(II,III) oxide and iron(III) oxide. This improves the absorption efficiency of infrared radiation in the wavelength range of at least 1 μm to 20 μm, and further improves the absorption efficiency of infrared radiation with wavelengths generally greater than 15 μm. [Explanation of Symbols]

[0037] 1. First substrate 2. Second substrate 11 Infrared detection element 21 Main body 22 Temperature sensing layer 23 Dielectric layer 24A~24F Electrode layer 25 Infrared absorption layer 34A, 34B First and second conductive supports 100 Infrared Sensors

Claims

1. Temperature sensing layer, It has an infrared absorbing layer provided separately from the temperature sensing layer, which absorbs infrared rays and converts them into heat, The temperature sensing layer and the infrared absorbing layer are thermally connected. The infrared absorbing layer is an infrared sensing element containing iron oxide.

2. The infrared detection element according to claim 1, wherein the iron oxide comprises at least one of iron(II,III) oxide and iron(III) oxide.

3. The infrared detection element according to claim 1, wherein at least a portion of the iron oxide has an inverse spinel structure.

4. The infrared sensing element according to 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 2 or more.

5. The infrared sensing element according to 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 3 or more.

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

7. An infrared sensing element according to any one of claims 1 to 3, having a dielectric layer provided between the temperature sensing layer and the infrared absorbing layer.

8. The temperature sensing layer comprises an electrode layer connected to either the incident surface to which the infrared light to be detected is incident, or the back surface of the incident surface, It has two electrode layers connected to the incident surface and the other side of the back surface, The one electrode layer and the two electrode layers supply a current to the temperature sensing layer in the direction of the thickness of the temperature sensing layer. The infrared sensing element according to any one of claims 1 to 3, wherein the aforementioned electrode layer is provided between the temperature sensing layer and the infrared absorbing layer.

9. The temperature sensing layer has two electrode layers electrically connected to it. The two electrode layers supply current to the temperature sensing layer in the in-plane direction of the temperature sensing layer. The infrared sensing element according to any one of claims 1 to 3, wherein the temperature sensing layer is in contact with the infrared absorbing layer, and the conductivity of the temperature sensing layer is higher than that of the infrared absorbing layer.

10. A main body including the temperature sensing layer and the infrared absorbing layer, The main body includes a substrate located on the side into which the infrared light to be detected is incident, A support column for supporting the main body on the substrate, An infrared detection element according to any one of claims 1 to 3, having the following characteristics.

11. An infrared sensor comprising an infrared detection element according to any one of claims 1 to 3.

12. A plurality of infrared detection elements according to any one of claims 1 to 3, The multiple infrared detection elements are arranged in an array in this infrared sensor.

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