JP2003304005A - Thermal infrared detecting element and light receiving element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make a thermal infrared detecting element gain a high sensitivity, by enhancing the infrared absorptance of an infrared absorbing member through sufficient reduction of its effective reflectance and improving the efficiency of converting infrared into thermal energy. <P>SOLUTION: The infrared absorbing member 10 has a laminated structure comprising a lower absorption layer 11 and upper absorption layers 13 each of which is separated by spaces formed by recessions 14 and is formed on the lower absorption layer 11. The upper surfaces of the upper absorption layers 13 function as upper reflection surfaces 15, while the parts of the upper surface of the lower absorption layer 11 that are exposed to the outside by the recessions 14 function as lower reflection surfaces 16. Respective reflected infrared rays that are reflected on the upper reflection layers 15 and on the lower reflection layers 16 are made to interfere with each other to effectively reduce the effective reflectance of the infrared absorbing member 10. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal infrared detecting element in which the effective reflectance of an infrared absorbing member that absorbs infrared rays and converts it into heat energy is reduced, and the effective reflectance is reduced. And a light receiving element.

[0002]

2. Description of the Related Art Infrared detecting elements for detecting infrared rays emitted from an object are roughly classified into a quantum type and a thermal type, depending on the difference in detection method. Quantum infrared detectors detect light as quantum by utilizing the effects of photoconductivity and photoelectromotive force, and while they have excellent sensitivity and response speed, they are easily affected by thermal noise, so they are cooled. Is required and the handling is complicated.

On the other hand, the thermal type infrared detecting element converts incident infrared rays into heat energy and utilizes the characteristic change of the detecting portion according to the heat energy, and is more sensitive than the quantum type infrared detecting element. Although it has poor response speed and response speed, it is widely used in various fields because it does not require cooling, is easy to handle, and has no wavelength selectivity. As such a thermal infrared detection element, various methods have been studied for its detection principle. Typical examples include a thermopile type that uses thermoelectromotive force of a thermocouple and a temperature change of a resistor. Practical applications of bolometer type, etc. that utilize resistance change,
It is popular.

The detection sensitivity of such a thermal-type infrared detecting element depends on the conversion efficiency of the infrared radiation emitted from the object into heat energy. Therefore, in the thermal infrared detection element, usually, an infrared absorption member made of a substance having a high infrared absorption rate is provided, and the infrared absorption is converted into heat energy by the infrared absorption member to improve the detection sensitivity. I am trying.

By the way, in order to make the infrared absorbing member sufficiently absorb the infrared rays emitted from the object, the effective reflectance of the infrared absorbing member is reduced as much as possible to suppress the loss due to the reflection at the infrared absorbing member. It is important to.

As a measure against the reflection on the infrared absorbing member, a conventional method is disclosed in, for example, Japanese Patent Laid-Open No. 2000-2059.
As described in Japanese Patent Laid-Open No. 44-44, a total reflection film is provided at a position λ / 4n away from the infrared absorption member, and the reflected infrared light reflected by the infrared absorption member and the total reflection film transmitted through the infrared absorption member. It is common to reduce the effective reflectance of the infrared absorbing member by interfering with the reflected infrared rays reflected by and canceling each other out. Here, λ is the wavelength of infrared rays, and n is the refractive index of the substance interposed between the infrared absorbing member and the total reflection film.

[0007]

However, in the conventional method as described in the above-mentioned Japanese Patent Laid-Open No. 2000-205944, in principle, the intensity of the reflected infrared light reflected by the infrared absorbing member and the total Since the intensity of the reflected infrared rays reflected by the reflection film is different, there is a problem that these reflected infrared rays cannot be completely canceled by mutual interference.

That is, since the reflected infrared light reflected by the total reflection film is the transmitted light that passes through the infrared absorbing member,
When passing through the infrared absorbing member, a part of the infrared absorbing member is absorbed and attenuated by the infrared absorbing member. Even if the attenuated reflected infrared rays interfere with the reflected infrared rays reflected by the infrared absorbing member, the reflected infrared rays reflected by the infrared absorbing member cannot be completely canceled out, and the effective reflection of the infrared absorbing member is prevented. It is difficult to reduce the rate sufficiently to effectively increase the infrared absorption rate.

In particular, the infrared absorbing member is provided for the purpose of absorbing infrared rays and increasing the efficiency of conversion into heat energy as described above, and is made of a substance having a high infrared absorption rate. The amount of attenuation of infrared rays that pass through tends to increase. Therefore, in the above method, the effective reflectance of the infrared absorbing member cannot be sufficiently reduced, and the absorptance of the infrared absorbing member cannot be sufficiently increased.

The present invention was conceived in view of the conventional circumstances as described above, and the effective reflectance of the infrared absorbing member is sufficiently reduced to increase the infrared absorption rate, and the infrared thermal energy is increased. It is an object of the present invention to provide a thermal-type infrared detection element having improved conversion efficiency to obtain high sensitivity and a light-receiving element having reduced effective reflectance to obtain high sensitivity.

[0011]

A thermal infrared detecting element according to the present invention absorbs incident infrared rays by an infrared absorbing member to convert it into thermal energy, and utilizes a characteristic change of a detecting portion in accordance with this thermal energy. And outputs an output value according to the intensity of the incident infrared ray, and the infrared absorbing member is disposed above the lower absorbing layer in a state of being spatially separated from the lower absorbing layer by the concave portion. A plurality of upper absorption layers, and the upper surface of the upper absorption layer serves as an upper reflection surface, and the upper surface of the lower absorption layer exposed to the outside by the recess serves as a lower reflection surface. It is characterized in that the reflected infrared rays reflected by the reflecting surface and the reflected infrared rays reflected by the lower reflecting surface interfere with each other to reduce the effective reflectance.

In the thermal infrared detecting element according to the present invention, since infrared rays propagating in the air are directly irradiated to both the upper reflecting surface and the lower reflecting surface of the infrared absorbing member, The intensity of the reflected infrared rays reflected by the upper reflecting surface and the intensity of the reflected infrared rays reflected by the lower reflecting surface are substantially equal. Since the reflected infrared rays having the same intensity are made to interfere with each other, the reflected infrared rays at the infrared absorbing member are almost completely canceled out, and the effective reflectance of the infrared absorbing member is effectively reduced. become.

In the thermal infrared detecting element according to the present invention, the lower absorbing layer of the infrared absorbing member may be an integral infrared absorbing film, or it may be spatially separated from the upper absorbing layer. You may make it arrange | position each at a different position. When the lower absorption layer of the infrared absorption member is made of an integral infrared absorption film, the infrared absorption member is easily manufactured, and the infrared absorption member is spatially separated and placed in a position different from that of the upper absorption layer. In this case, the heat capacity is reduced, which is advantageous in improving the response speed.

When the lower absorption layer of the infrared absorbing member is spatially separated and arranged at a position different from that of the upper absorption layer, the lower absorption layer has, for example, a thermopile or the like. The thermal infrared detection element can be simplified in structure, and it is advantageous in reducing the thickness of the thermal infrared detection element as a whole.

Further, in the thermal infrared detecting element according to the present invention, an intermediate layer made of a substance different from the upper absorbing layer and the lower absorbing layer is provided between the upper absorbing layer and the lower absorbing layer of the infrared absorbing member. It may be provided. In this way, when the intermediate layer is provided between the upper absorption layer and the lower absorption layer of the infrared absorption member, the manufacturing accuracy of the upper absorption layer is improved and the damage of the lower absorption layer is reduced. Can be expected.

Further, in the thermal infrared detecting element according to the present invention, the upper absorption layer and the lower absorption layer of the infrared absorption member are made of a material having the same reflection characteristic with respect to incident infrared rays, or the same material. Is desirable. As described above, when the upper absorption layer and the lower absorption layer are made of a material having the same reflection characteristics with respect to the incident infrared rays or the same material, the reflected infrared rays and the lower reflection rays reflected by the upper reflection surface are reflected. Amplitude and phase characteristics can be matched with the reflected infrared rays reflected by the surface, and the effective reflectance of the infrared absorbing member can be reduced more effectively.

Further, the light receiving element according to the present invention has a spatially separated upper reflection surface and a lower reflection surface on which light is directly incident, and reflected light reflected by the upper reflection surface. It is characterized in that the reflected light reflected by the lower reflection surface interferes with each other to reduce the effective reflectance.

In the light receiving element according to the present invention, the intensity of the reflected light reflected by the upper reflecting surface and the intensity of the reflected light reflected by the lower reflecting surface become substantially equal, and the reflected light having the same intensity is obtained. Since the mutual interference is almost completely canceled by the mutual interference, the effective reflectance is effectively reduced.

[0019]

According to the thermal infrared ray detecting element of the present invention, the reflected infrared ray reflected by the upper reflecting surface and the reflected infrared ray reflected by the lower reflecting surface of the infrared absorbing member are almost completely interfered with each other. Since the effective reflectance of the infrared absorbing member is effectively reduced, the infrared radiation emitted from the object to be detected is absorbed by the infrared absorbing member at a high absorption rate, and the conversion efficiency of infrared rays into heat energy is improved. As a result, it is possible to improve the detection sensitivity.

Further, according to the light receiving element of the present invention, the reflected light reflected by the upper reflecting surface and the reflected light reflected by the lower reflecting surface are almost completely canceled by mutual interference, and effective reflection is achieved. Since the rate is effectively reduced, the detection sensitivity can be improved.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. Here, the present invention relates to a thermopile type thermal infrared detecting element in which a large number of thermocouples are connected in series and the infrared radiation from a detection target is detected by utilizing the thermoelectromotive force of these thermocouples. Will be specifically described with reference to an example to which is applied.

(First Embodiment) FIG. 1 is a sectional view showing a structural example of a thermopile type thermal infrared detecting element to which the present invention is applied. The thermal infrared detection element 1 shown in FIG.
The detection unit 4 having a thermopile is provided on the main surface of the silicon substrate 2 having the cavity 2a for heat separation via the membrane 3, and the infrared absorption member 10 is provided on the detection unit 4. There is.

The membrane 3 supports the detecting portion 4 and the infrared absorbing member 10 in a state of being positioned above the cavity 2a of the silicon substrate 2 and thermally separated from the silicon substrate 2, and is made of, for example, a nitride film or the like. The cavity 2a of the silicon substrate 2 is formed, for example, on the main surface portion of the silicon substrate 2 by sequentially laminating the films forming the membrane 3, the detection unit 4, and the infrared absorbing member 10, and then forming one of the nitride films forming the membrane 3. The silicon substrate 2 is formed by forming an etching solution supply hole in the portion by a method such as dry etching and etching the silicon substrate 2 with a heated anisotropic etching solution such as hydrazine hydrate.

The detecting section 4 is for generating an electromotive force according to a temperature change, and has a plurality of p-type polysilicons 5 and n-type polysilicons 6. The plurality of p-type polysilicons 5 and n-type polysilicons 6 are connected to each other via the contact holes by a wiring member 7 made of a conductive material such as aluminum.
Are alternately connected in series to form one thermopile. The p-type polysilicon 5, the n-type polysilicon 6, and the wiring member 7 are covered with an oxide film 8 to protect the surface.

The infrared absorbing member 10 absorbs infrared rays emitted from the object to be detected and converts it into heat energy, and is formed on the oxide film 8 covering the wiring member 7 of the detecting section 4. In the thermal infrared detecting element 1 to which the present invention is applied, the effective reflectance of the infrared absorbing member 10 is significantly reduced, and the infrared absorbing rate is improved. The infrared absorbing member 10 will be described in detail later.

In the thermal type infrared detecting element 1 to which the present invention having the above-mentioned structure is applied, when the infrared ray radiated from the object to be detected is incident on the infrared absorbing member 10, the incident infrared ray passes through the infrared absorbing member 10. When this is done, it is absorbed by this infrared absorbing member 10 and converted into heat energy. As will be described later, the infrared ray absorbing member 10 has a reduced effective reflectance and an increased infrared ray absorptivity, so that the infrared ray is efficiently converted into heat energy.

The thermal energy converted from infrared rays by the infrared absorbing member 10 is transferred to the contact portion (warm contact) located near the infrared absorbing member 10 through the oxide film 8 of the detecting portion 4 by heat conduction, The temperature of the p-type polysilicon 5 and the n-type polysilicon 6 of the hot junction is raised. At this time, since the cavity 2a for heat separation is formed in the lower part of the hot junction, the heat from the hot junction is not transmitted to the silicon substrate 2 but is transmitted only through each film formed on the membrane 3. I will go. However, since each film formed on the membrane 3 is thin and has high thermal resistance, the heat from the hot junction is not easily transmitted to the contact portion (cold junction) located away from the infrared absorbing member 10, and the heat is not transmitted. There will be a temperature difference between the contact and the cold junction. As a result, an electromotive force is generated due to the Bezek effect, and a voltage value according to the intensity of incident infrared rays is output.

Here, the infrared absorbing member 10, which is a characteristic part of the thermal infrared detecting element 1 to which the present invention is applied, will be described in more detail with reference to FIG.

The infrared absorbing member 10 is formed on the oxide film 8 of the detecting section 4 and has a laminated structure in which a lower absorbing layer 11, an intermediate layer 12 and an upper absorbing layer 13 are laminated in this order.

The lower absorption layer 11 is made of, for example, a silicon oxide film or the like in which fine metal particles serving as a light absorbing material are mixed and turbid, and is formed as an integral film on the oxide film 8 of the detection unit 4. Then, the recess 14 is formed on the lower absorption layer 11.
The plurality of upper absorption layers 13 are laminated with the intermediate layer 12 interposed therebetween in the state of being spatially separated by. As the material of the lower absorption layer 11, any material that reflects less infrared light and absorbs much infrared light can be applied. For example, a black metal film or the like may be used as the lower absorption layer 11.

Like the lower absorption layer 11, the plurality of upper absorption layers 13 are made of, for example, a silicon oxide film in which fine metal particles are mixed and turbid, and the recesses 14 are formed in a direction orthogonal to the incident direction of infrared rays. They are placed adjacent to each other. As the material of the upper absorption layer 13, as with the material of the lower absorption layer 11, any material that reflects less infrared light and absorbs much infrared light is applicable. The lower absorption layer 11 and the upper absorption layer 13 are preferably made of a material having the same reflection characteristic with respect to incident infrared rays, or the same material.

Further, the intermediate layer 12 is made of a germanium thin film or the like and, like the upper absorption layer 13, is spatially separated by the recess 14, and the lower absorption layer 11 and the upper absorption layer 1 are separated from each other.
It is arranged between 3 and 3. The intermediate layer 12 does not necessarily contribute to the absorption of the incident infrared rays in the infrared absorbing member 10, so it is not necessarily provided, but the lower absorption layer 11
When the intermediate layer 12 is provided between the upper absorption layer 13 and the upper absorption layer 13, it is expected that the manufacturing accuracy of the upper absorption layer 13 is improved and the damage of the lower absorption layer 11 is reduced.

The infrared absorbing member 10 having the above structure
Can be easily manufactured by a general semiconductor manufacturing process such as lift-off. Specifically, for example, after forming a lower absorption layer 11 on the oxide film 8 of the detection unit 4, a patterned resist mask that covers the formation position of the recess 14 is formed on the lower absorption layer 11. Then, the material of the intermediate layer 12 and the material of the upper absorption layer 13 are sequentially formed on the lower absorption layer 11 on which the resist mask is formed, and the recess 14 is formed.
The resist mask covering the formation position of is removed together with the material formed on the resist mask. Thereby, the infrared absorbing member 10 having a structure in which the intermediate layer 12 and the upper absorption layer 13 are spatially separated by the recess 14 and stacked on the lower absorption layer 11 is manufactured.

The infrared absorbing member 10 as described above has a comb-shaped cross section, and the infrared rays radiated from the detection object and propagating in the air are the upper surface of the upper absorption layer 13 (the upper reflection surface 15). And the concave portion 1 on the upper surface of the lower absorption layer 11.
Part exposed to the outside by 4 (lower reflecting surface 16)
Both will be directly irradiated. Then, the infrared rays from the detection target are reflected by both the upper reflecting surface 15 and the lower reflecting surface 16. If the upper absorption layer 13 and the lower absorption layer 11 both have a refractive index n.
If it is formed of the material of No. 1, ((n1-1) /
The reflection of (n1 + 1) ² will occur on both the upper reflecting surface 15 and the lower reflecting surface 16.

In the infrared absorbing member 10 of the thermal infrared detecting element 1 to which the present invention is applied, the distance D between the upper reflecting surface 15 and the lower reflecting surface 16 in the height direction, that is, the intermediate layer 1
2 and the total thickness D of the upper absorption layer 13 is set to λ / 4n. It should be noted that λ is the wavelength of infrared rays emitted from the detection target, and n is the refractive index of the medium in which the infrared rays propagate (in this example, infrared rays propagate in the air, so n = 1 may be considered). Specifically, for example, when the detection target is a human body and the wavelength λ of infrared radiation is about 10 μm, the distance D between the upper reflecting surface 15 and the lower reflecting surface 16 is set to about 2.5 μm.

The distance L between the adjacent upper absorption layers 13 of the infrared absorbing member 10, that is, the width L of the recess 14 is
The wavelength is set to be equal to or less than twice the wavelength λ of infrared radiation emitted from the detection target, and preferably to be equal to or less than the wavelength λ of infrared radiation emitted from the detection target. Specifically, for example, when the detection target is a human body and the wavelength λ of the infrared radiation is about 10 μm, the adjacent upper absorption layer 1
The distance L between the three is set to 20 μm or less.

Since the infrared absorbing member 10 has the above structure, the optical path difference between the reflected infrared light reflected by the upper reflecting surface 15 and the reflected infrared light reflected by the lower reflecting surface 16 is λ. / 2, and the phase of the reflected infrared light reflected by the upper reflection surface 15 and the phase of the reflected infrared light reflected by the lower reflection surface 16 are different by 180 °. Further, since both of these reflected infrared rays propagate in the air, they are hardly attenuated in the process of propagation. Therefore, the reflected infrared rays reflected by the upper reflecting surface 15 and the reflected infrared rays reflected by the lower reflecting surface 16 have substantially the same amplitude and opposite phases to each other. The mutual interference between them cancels out the reflected infrared rays from the infrared absorbing member 10 almost completely, and effectively reduces the effective reflectance of the infrared absorbing member 10. In particular, when the lower absorption layer 11 and the upper absorption layer 13 are made of a material having the same reflection characteristic with respect to the incident infrared rays or the same material, the reflected infrared rays reflected by the upper reflection surface 15 The amplitude and phase characteristics can be almost completely matched by the reflected infrared rays reflected by the lower reflection surface 16, and the effective reflectance of the infrared absorbing member 10 can be more effectively reduced. Thereby, the absorption rate of infrared rays in the infrared absorbing member 10 is increased, and the efficiency of conversion of infrared rays into heat energy is improved.

In the thermal infrared detecting element 1 to which the present invention is applied, as described above, the effective reflectance of the infrared absorbing member 10 is reduced and the infrared absorptivity is increased, so that the infrared radiation emitted from the object to be detected is efficient. Since it is well converted into heat energy, it is possible to detect infrared rays emitted from the detection target with extremely high sensitivity.

The thermal infrared detecting element 1 described above is used.
Then, various structural changes in details can be made within a range in which the object of the present invention can be achieved. Specifically, in the above example, the lower absorption layer 11 of the infrared absorption member 10 is configured as an integral film, but the thermal infrared detection element 1 according to the present invention is applied.
Then, the lower absorption layer 11 is spatially separated and the upper absorption layer 1 is separated.
Even if they are arranged at positions different from 3, the same effect can be obtained. However, when the lower absorption layer 11 of the infrared absorbing member 10 is formed as an integral film, the infrared absorbing member 10 can be easily manufactured. On the other hand, when the lower absorption layer 11 of the infrared absorption member 10 is spatially separated and disposed at a position different from that of the upper absorption layer 13, the heat capacity of the lower absorption layer 11 is reduced, so that the response speed It is advantageous for improvement.

(Second Embodiment) FIG. 3 is a sectional view showing another structural example of the thermal infrared detecting element to which the present invention is applied. The thermal infrared detection element 20 shown in FIG. 3 has the same basic configuration as the thermal infrared detection element 1 described above, and the lower absorption layer 11 of the infrared absorption member 10 is spatially separated to form the concave portion 1.
Embedded in the oxide film 8 of the detector 4 located immediately below
The lower absorption layer 11 is characterized in that it functions as the wiring member 7 at the hot junction of the detection unit 4. In the thermal infrared detecting element 20 shown in FIG. 3, the same components as those of the thermal infrared detecting element 1 described above are denoted by the same reference numerals in the figure, and detailed description thereof will be omitted.

In this thermal infrared detecting element 20, the lower absorption layer 11 of the infrared absorption member 10 is spatially separated, so that the heat capacity of the lower absorption layer 11 itself is reduced. In addition, the spatially separated lower absorption layer 11 is embedded in the oxide film 8 of the detection unit 4, and the wiring member 7 at the hot junction is formed.
Since it is not necessary to insulate the lower absorption layer 11 and the wiring member 7 with the oxide film 8 as in the thermal infrared ray detecting element 1 described above, the oxide film 8 is thinned accordingly. It is possible. As a result, the total heat capacity can be further reduced.

In this thermal infrared detecting element 20, as described above, the lower absorption layer 11 of the infrared absorbing member 10 is spatially separated and embedded in the oxide film 8 of the detecting portion 4 located immediately below the recess 14. In addition, since the lower absorption layer 11 has a structure that functions as the wiring member 7 at the hot junction of the detection unit 4 and a large reduction in heat capacity is realized, like the thermal infrared detection element 1 described above. In addition to enabling highly sensitive detection, the response speed will be improved.

Further, in this thermal infrared detecting element 20,
Since the lower absorption layer 11 of the infrared absorption member 10 functions as the wiring member 7 at the hot junction of the detection unit 4, the structure can be simplified and the number of manufacturing steps can be reduced, and the detection unit 4 and infrared rays can be reduced. The absorbing member 10 can be made thinner, and the mechanical characteristics of the membrane 10 supporting them can be improved.

(Third Embodiment) FIG. 4 is a sectional view showing still another example of the structure of a thermal infrared detecting element to which the present invention is applied. The thermal infrared detection element 30 shown in FIG. 4 has the same basic configuration as the thermal infrared detection element 1 described above, and has an upper reflection surface 15 which is the upper surface of the upper absorption layer 13 of the infrared absorption member 10 and a lower absorption layer. Both the lower reflection surface 16 which is a portion exposed to the outside by the concave portion 14 on the upper surface of 11 is
Similar to the material of the intermediate layer 12, it is characterized in that it is covered with a cover layer 17 made of a material having a high transmittance for infrared rays such as germanium. In the thermal infrared detecting element 30 shown in FIG. 4, the same components as those of the thermal infrared detecting element 1 described above are denoted by the same reference numerals in the figure, and detailed description thereof will be omitted.

In this thermal infrared detecting element 30, the infrared rays transmitted through the cover layer 17 are applied to the upper reflecting surface 15 and the lower reflecting surface 16 of the infrared absorbing member 10. In this case, for example, germanium having a refractive index n of 4 is used as the material of the cover layer 17, and the infrared wavelength λ is about 10
If the distance is μm, the distance D between the upper reflecting surface 15 and the lower reflecting surface 16 is set to about 0.6 μm. Further, in this case, it is necessary to consider the reduction of the effective reflectance on the surface of the cover layer 17, so that the cover formed on the upper reflective surface 15 and the cover formed on the lower reflective surface 16 are covered. The distance from the surface of the layer 17 is preferably set to about 2.5 μm.

As described above, the thermal infrared detecting element 30 has a structure in which the upper reflecting surface 15 and the lower reflecting surface 16 of the infrared absorbing member 10 are covered with the cover layer 17, respectively. In addition to enabling high-sensitivity detection as in the case of the infrared detector 1, the infrared absorbing member 10 can be effectively prevented from deteriorating with time, and the service life can be extended.

In the above, the present invention has been specifically described with reference to an example in which the present invention is applied to a thermopile type thermal infrared detecting element, but the present invention is not limited to the above examples and other examples. The same can be applied to an infrared detection element that detects infrared rays by the method. Further, the principle of the present invention can be effectively applied not only to the infrared detecting element but also to any type of light receiving element.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing one structural example of a thermal infrared detection element to which the present invention is applied.

FIG. 2 is an enlarged sectional view showing an infrared absorbing member of the thermal infrared detecting element.

FIG. 3 is a cross-sectional view showing another configuration example of the thermal infrared detection element to which the present invention is applied.

FIG. 4 is a cross-sectional view showing another configuration example of the thermal infrared detection element to which the present invention is applied.

[Explanation of symbols]

1 Thermal infrared detector 4 detector 7 wiring members 10 Infrared absorbing member 11 Lower absorption layer 12 Middle class 13 Upper absorption layer 14 recess 15 Upper reflective surface 16 Lower reflective surface 20 Thermal infrared detector 30 Thermal infrared detector

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) // G01J 5/02 H01L 27/14 K F term (reference) 2G065 AB02 BA11 BB24 BB50 DA20 2G066 BA08 BA55 BA60 4M118 AA01 AB01 BA05 BA30 CA03 CA14 CA32 CA34 CB07 EA01 EA04 GA10

Claims (7)

[Claims] 1. An incident infrared ray is absorbed by an infrared absorbing member and converted into heat energy, and an output value corresponding to the intensity of the incident infrared ray is output by utilizing a characteristic change of a detection unit according to the heat energy. In the thermal infrared detection element, the infrared absorption member has a lower absorption layer and a plurality of upper absorption layers arranged above the lower absorption layer in a state of being spatially separated by a recess, and the upper part The upper surface of the absorbing layer is an upper reflecting surface, and the upper surface of the lower absorbing layer exposed to the outside by the recess is a lower reflecting surface, and the infrared rays reflected by the upper reflecting surface and the lower infrared ray. A thermal infrared detecting element characterized in that effective infrared reflectance is reduced by mutual interference with reflected infrared rays reflected by a reflecting surface. 2. The thermal infrared detection element according to claim 1, wherein the lower absorption layer of the infrared absorption member is an integral infrared absorption film. 3. The thermal infrared detecting element according to claim 1, wherein the lower absorption layer of the infrared absorption member is spatially separated and arranged at a position different from that of the upper absorption layer. . 4. The thermal infrared detection element according to claim 3, wherein the lower absorption layer of the infrared absorption member has a function as a wiring member of the detection unit. 5. The infrared absorbing member according to claim 1, wherein the infrared absorbing member has an intermediate layer made of a different substance between the lower absorbing layer and the upper absorbing layer. Thermal infrared detector. 6. The lower absorption layer and the upper absorption layer of the infrared absorbing member are made of a material having the same reflection characteristics with respect to the incident infrared rays, or the same material. 6. The thermal infrared detecting element according to any one of 1 to 5. 7. A spatially separated upper reflection surface and a lower reflection surface on which light is directly incident, wherein reflected light reflected on the upper reflection surface and reflected light on the lower reflection surface. A light-receiving element characterized in that the effective reflectance is reduced by the interference of the reflected light with each other.