JP2002221449A - Radiation detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve both the sensitivity of detection and the response of detection. SOLUTION: A displacement section is supported by a substrate 1 through a leg member 2, 3 rising from the substrate 1. The displacement section 4 includes an infrared absorbing section 5 absorbing infrared rays i and moves for the substrate 1 in accordance with the heat generated at the infrared absorbing section 5. The infrared absorbing section 5 has a property by which a portion of the incident infrared rays i is reflected. A radiation reflective member 12 on which the total reflection of the infrared rays i approximately occurs is disposed at a prescribed interval from the infrared absorbing section 5. The infrared absorbing section 5 includes plural films 71, 72 laminated each other in the direction of the prescribed interval. Each material forming the plural films 71, 72 is different from that of the other adjacent laminated film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation detecting device such as a thermal infrared detecting device, and more particularly, to a radiation absorbing section which absorbs incident radiation such as infrared rays and converts it into heat and converts the heat into displacement. And a radiation detecting device for detecting radiation.

[0002]

2. Description of the Related Art Conventionally, as such a radiation detecting device, for example, a capacitance type radiation detecting device (US Pat. No. 5,844,238, etc.) and a light reading type radiation detecting device (Japanese Patent Laid-Open No. No. 10-253474) has been proposed. The capacitance type radiation detection device reads out the displacement generated in response to incident radiation as a change in capacitance, and the optical readout type radiation detection device irradiates the displacement generated in response to incident radiation separately. This is read out as a change in the readout light.

[0003]

In the above-described radiation detecting apparatus, it is required that the radiation absorbing portion has a high radiation absorption rate in order to increase the detection sensitivity. Further, in order to enhance the response of detection, it is required that the heat capacity of the radiation absorbing section is small. Further, in order to enhance the detection sensitivity, it is required that the heat generated in the radiation absorbing section is efficiently transmitted to the displacement generating portion of the displacement section.

However, in the above-described radiation detecting device, even if a gold black (Gold Black) film having a relatively high absorption efficiency is used as the radiation absorbing portion, radiation such as infrared rays simply enters the film. , It is not possible to increase both the detection sensitivity and the detection response.

That is, the absorption coefficient of gold black is, for example, 8 to
Approximately 960 cm ⁻¹ for infrared rays in a wavelength range of 12 μm.
(G. Zaeschmar and A. Nedoluha, "Theory
of the Optical Properties of Gold Blacks ", JOURNAL
OF THE OPTICAL SOCIETY OFAMERICA, VOLUME 62, NUMB
ER 3, March 1972, pp. 348-352 ”). When the infrared absorptance of gold black having a film thickness of 1 μm is determined from this absorption coefficient, it is found that it is only about 9%. Accordingly, in order to sufficiently increase the infrared absorptance of the radiation absorbing portion formed of the gold black film, the thickness of the gold black film must be considerably increased. As described above, merely by irradiating the radiation such as infrared rays to the radiation absorbing portion composed of the gold black film cannot increase the infrared absorptance while reducing the thickness of the film. It is difficult to increase both detection sensitivity and detection response.

Accordingly, the present inventor has proposed that a substrate and a displacement portion supported by the substrate, which has a radiation absorbing portion composed of a single film that absorbs radiation, have heat generated by the radiation absorbing portion. And a displacement section that is displaced with respect to the base according to the following. The radiation absorption section has a characteristic of reflecting a part of incident radiation, n is an odd number, and ₀ a center wavelength λ of the wavelength range of the radiation detector having a radiation reflective portion in which the spaced of approximately n [lambda _0/4 from the radiation absorber to substantially totally reflecting the radiation, and the invention .

[0007] According to this radiation detecting device, since the optical cavity structure is skillfully used, the radiation absorptivity of the radiation absorbing portion is increased. Therefore, even if the heat absorption capacity is reduced by reducing the thickness of the radiation absorbing section, the radiation absorption rate can be increased. As a result, both detection sensitivity and detection responsiveness can be increased.

As described above, the radiation detecting apparatus according to the inventor's prior invention is significantly superior to the above-described prior art. However, as a result of further research by the present inventor, the radiation detecting apparatus has been described. Turned out to have room for improvement.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a radiation detection apparatus capable of further improving both detection sensitivity and detection response.

[0010]

According to a first aspect of the present invention, there is provided a radiation detecting apparatus having a radiation absorbing section for absorbing radiation, wherein the radiation absorbing section includes a radiation absorbing section. It has a characteristic of reflecting a part of the incident radiation, and comprises a radiation reflecting portion arranged at a predetermined interval from the radiation absorbing portion and substantially totally reflecting the radiation, wherein the radiation absorbing portion has the predetermined interval. A plurality of films stacked one on another in the direction, each of the plurality of films being formed of a different material from other films stacked adjacent to the film.

The radiation may be not only infrared rays but also invisible light such as X-rays and ultraviolet rays, and various other types of radiation. This is the same for each embodiment described later.

According to the first aspect, radiation is incident on the radiation absorbing section from the side opposite to the radiation reflecting section. Since the radiation absorbing part and the radiation reflecting part are arranged at a predetermined interval,
If the interval is appropriately set, basically, the absorption rate of the radiation in the radiation absorbing portion is increased by the principle of the optical cavity, similarly to the radiation detection device according to the inventor's prior invention. Therefore, even if the heat absorption capacity is reduced by reducing the thickness of the radiation absorbing section, the radiation absorption rate can be increased. As a result, both detection sensitivity and detection responsiveness can be increased.

As a result of the research of the present inventor, as described in the first aspect, when the radiation absorbing portion is constituted by a plurality of films that are stacked and adjacent to each other and formed of different materials, As compared with the case where the radiation absorption unit is formed of a single film as in the radiation detection device according to the prior invention, the absorption rate in the absorption rate characteristics (spectral absorption characteristics) corresponding to each wavelength of the incident radiation is higher. It has been found that it is possible to widen the range of wavelengths to be increased. As described above, if the range of wavelengths having a high absorptance can be expanded, the absorptance (corresponding to the absorptivity integrated with the wavelength) of the entire desired wavelength region can be increased. Further, even if the radiation absorbing section is constituted by a plurality of films, the overall thickness can be reduced.

Therefore, according to the first aspect, the detection sensitivity can be further improved as compared with the radiation detection apparatus according to the inventor's prior invention.

According to a second aspect of the present invention, there is provided the radiation detecting apparatus according to the first aspect, wherein n is an odd number, and a center wavelength of a desired wavelength range of the radiation is λ ₀ , in a thickness direction of the radiation absorbing portion. centered between the reflective surface of the radiation reflection portion, the distance in the direction of the predetermined distance, one that is approximately nλ _0/4.

According to this second embodiment, since the distance is set to approximately n [lambda _0/4, the principle of the optical cavity, the absorption rate of radiation absorbing portion is more increased, preferably.

A radiation detecting apparatus according to a third aspect of the present invention is a radiation detecting apparatus having a radiation absorbing section for absorbing radiation, wherein the radiation absorbing section has a characteristic of reflecting a part of incident radiation. A radiation reflecting portion disposed at a predetermined interval from the radiation absorbing portion and substantially totally reflecting the radiation, wherein the radiation absorbing portion is provided with a plurality of individual portions arranged at intervals in the direction of the predetermined interval. It has a radiation absorption part, and each of the plurality of individual radiation absorption parts has a single film or a plurality of films stacked in the direction of the predetermined interval.

According to the third aspect, each of the plurality of individual radiation absorbing portions and the radiation reflecting portion constitute an optical cavity structure in which the distance between them is different from each other. Become. Therefore, as in the case of the radiation detection apparatus according to the inventor's prior invention, the absorptance of radiation in each individual radiation absorption unit is increased by the principle of an optical cavity, and as a result, each individual radiation absorption unit as a whole is The absorption rate of the radiation in the radiation absorption section of the above can be increased, and both the detection sensitivity and the detection responsiveness can be increased. According to the third aspect, as in the case where a plurality of optical cavity structures having different wavelength dependences are shared, the absorption characteristics of the radiation absorption unit are different from those of the individual radiation absorption units. It is the same as the one with the addition of the absorption characteristics. Therefore, by appropriately setting the distance of each individual radiation absorbing section from the radiation reflecting section, for example, the wavelength at which the absorption rate of one individual radiation absorbing section becomes a peak and the absorption rate of another individual radiation absorbing section become equal. If the peak wavelength coincides with or approaches the peak wavelength, the detection sensitivity can be further increased in a desired wavelength range as compared with the radiation detection apparatus according to the present invention, as in the first aspect. Can be. Also, for example, if the wavelength at which the absorption rate of one individual radiation absorption section peaks and the wavelength at which the absorption rate of the other individual radiation absorption section peaks are relatively far from each other, the absorption rate of the radiation absorption section can be increased. Will have peaks in multiple wavelength ranges,
A radiation detection device having sensitivity in a plurality of wavelength ranges can be obtained.

According to a fourth aspect of the present invention, in the radiation detecting apparatus according to the third aspect, at least one of the plurality of individual radiation absorbing portions is stacked on each other in a direction of the predetermined interval. Each of the plurality of films is formed of a different material from other films stacked adjacent to the film.

According to a fourth aspect, in the at least one individual radiation absorbing section of the third aspect, the first
This corresponds to the configuration employing the structure of the radiation absorbing section in the aspect described above. Therefore, according to the fourth aspect, the third aspect
While the advantage of the embodiment is obtained, the absorptance of the at least one individual radiation absorber can be further increased, which is preferable.

According to a fifth aspect of the present invention, there is provided the radiation detecting apparatus according to the third or fourth aspect, wherein n is an odd number, and λ ₁ is a center wavelength of a desired first wavelength range of the radiation. The distance in the direction of the predetermined interval between the center in the thickness direction of at least one of the individual radiation absorbing sections of the individual radiation absorbing sections and the reflecting surface of the radiation reflecting section is substantially nλ ₁ /.
4.

According to the fifth aspect, since the distance is set to approximately n [lambda _1/4, the principle of the optical cavity, the individual radiation absorbing portion absorbing rate of more increased, preferably.

The radiation detecting apparatus according to a sixth aspect of the present invention is the radiation detecting apparatus according to the fifth aspect, wherein m is an odd number, and λ ₂ is a center wavelength of a desired second wavelength range of the radiation. between at least one other center and the reflective surface of the radiation reflection portion in the thickness direction of the individual radiation absorbing portion of the absorbent portion, the distance in the direction of the predetermined interval, what is approximately m [lambda _2/4 It is.

According to the sixth aspect, since the distance is set to approximately m [lambda _2/4, the principle of the optical cavity, the individual radiation absorbing portion absorbing rate of more increased, preferably. According to the sixth aspect, it is possible to obtain a radiation detection device having sensitivity in at least both the first and second wavelength ranges.

In a radiation detecting apparatus according to a seventh aspect of the present invention, in any one of the first to sixth aspects, each of the films included in the radiation absorbing portion partially transmits infrared light.

According to the seventh aspect, since each of the films included in the radiation absorbing portion partially transmits infrared light, the radiation to be detected can be infrared light.

According to an eighth aspect of the present invention, there is provided a radiation detection apparatus according to any one of the first to seventh aspects, further comprising: a base; and a displacement unit supported by the base. A radiation absorbing portion that is displaced with respect to the base in accordance with heat generated in the radiation absorbing portion, and a relative position between the radiation reflecting portion and the radiation absorbing portion regardless of displacement of the displacement portion; The radiation reflecting portion is provided on the displacement portion so that the relationship is maintained substantially constant.

The radiation detecting apparatus according to the first to seventh aspects includes a base and a displacement part supported by the base, wherein the displacement part has the radiation absorption part and has a radiation absorption part. The substrate may be displaced with respect to the base in accordance with the generated heat. Further, the radiation detection devices according to the first to seventh aspects may not be provided with a displacement unit, such as an infrared detection device using a bolometer or a pyroelectric body.

When the radiation detecting apparatus according to the first to seventh aspects is provided with the displacement section, for example, an optical reading type radiation detection apparatus for reading out a displacement generated in the displacement section as a change in readout light irradiated separately. It may be configured as a device, or may be configured as a capacitance type radiation detection device that reads out the displacement generated in the displacement portion as a change in capacitance. When configured as an optical readout type radiation detection device, for example, a readout light reflection unit that reflects received readout light as a displacement readout member used to obtain a predetermined change according to the displacement generated in the displacement unit May be provided in the displacement part. In the case of being configured as a light reading type radiation detection device, for example, a read light half mirror unit is provided in the displacement unit as a displacement read member used to obtain a predetermined change according to the displacement generated in the displacement unit. Alternatively, a reading light reflecting portion may be provided on the base so as to face the reading light half mirror portion. Further, when configured as a capacitance type radiation detection device, for example, a movable electrode section is provided in the displacement section as a displacement readout member used to obtain a predetermined change according to the displacement generated in the displacement section, A fixed electrode section may be provided on the base so as to face the movable electrode section.

In the first to seventh aspects, even when the displacement section is provided, the radiation reflection section does not necessarily need to be provided in the displacement section. However, as in the eighth aspect, the radiation reflecting portion is displaced so that the relative positional relationship between the radiation reflecting portion and the radiation absorbing portion is kept substantially constant regardless of the displacement of the displacement portion. When provided in the portion, stable spectral sensitivity characteristics can be obtained even when the displacement portion is displaced.
That is, according to the eighth aspect, the distance between the radiation reflecting portion and the radiation absorbing portion is kept substantially constant regardless of the displacement of the displacement portion, so that the radiation absorbing portion absorbs the radiation. Is performed according to the principle of interference, so that the wavelength range of the radiation absorbed by the radiation absorbing section is kept constant without change.

[0031] In the eighth aspect, there is provided a reading light reflecting portion provided on the displacement portion for reflecting the received reading light, and the radiation reflecting portion is also used as the reading light reflecting portion or the reading light reflecting portion. It may be formed on the reflection part. This is an example configured as an optical readout type radiation detection device. If the radiation reflection part is also used as the readout light reflection part or is formed in the readout light reflection part as in this example, the structure becomes simple and it can be provided at low cost.

[0032] In the eighth aspect, there is provided a fixed electrode portion provided on the base, and a movable electrode portion provided on the displacement portion and facing the fixed electrode portion, wherein the radiation reflection portion is provided with the movable electrode portion. It may be used also as a part or may be formed on the movable electrode part. This is an example configured as a capacitance type radiation detection device. When the radiation reflection portion also serves as the movable electrode portion as in this example, the structure is simplified and the cost can be reduced.

[0033] In any one of the first to seventh aspects, there may be provided a base, and a displacement portion supported by the base, wherein the displacement portion has the radiation absorbing portion and is generated at the radiation absorbing portion. Displaced with respect to the base in response to the applied heat, comprising a fixed electrode portion provided on the base, and a movable electrode portion provided on the displacement portion and facing the fixed electrode portion, wherein the radiation reflection portion is It may be used also as a fixed electrode part. This example is also an example configured as a capacitance type radiation detection device. When the radiation reflecting portion also serves as the fixed electrode portion as in this example, the structure is simplified and the cost can be reduced.

[0034] In any one of the first to seventh aspects, there is provided a base, and a displacement portion supported by the base, wherein the displacement portion has the radiation absorbing portion and is generated by the radiation absorbing portion. Displaced with respect to the base in response to the applied heat, comprising a fixed electrode portion provided on the base, and a movable electrode portion provided on the displacement portion and facing the fixed electrode portion, wherein the radiation absorbing portion is It may be used also as a movable electrode part. This example is also an example configured as a capacitance type radiation detection device. When the radiation absorbing portion also serves as the movable electrode portion as in this example, the structure is simplified and the device can be provided at low cost.

In the first to seventh aspects,
A base, and a displacement part supported by the base, wherein the displacement part has the radiation absorbing part and is displaced with respect to the base in response to heat generated in the radiation absorbing part. At least one of the absorbing portion and the radiation reflecting portion provided in the displacement portion has a flat portion formed of one or more layers of films, and is supported such that the flat portion is positioned in the air. In this case, it is preferable to form a rising portion or a falling portion that rises or falls from the plane portion over at least a part of a peripheral portion of the plane portion. Alternatively, at least one of the radiation absorbing portion and the radiation reflecting portion, provided in the displacement portion, has a flat portion including a plurality of layers of films and is supported such that the flat portion is positioned in the air. In the case of a member, at least one of the films of the plurality of layers covers at least a part of a peripheral portion of the plane portion.
It is preferable that the layer film is formed so as to cover an edge portion of at least one other layer film of the plurality of layer films.

In these cases, the radiation absorbing portion and / or the radiation reflecting portion provided in the displacement portion may be formed by a rising portion or a falling portion, or at least one layer may be formed by another film. The at least one layer is reinforced by a portion covering an edge portion of the film. Therefore, it is possible to reduce the thickness of the flat portion while securing the desired strength of the flat portion. For this reason, it is possible to reduce the heat capacity of at least one of the radiation absorbing portion and the radiation reflecting portion provided in the displacement portion, while preventing deformation due to insufficient strength. As a result, it is possible to prevent a change in the distance between the radiation absorbing portion and the radiation reflecting portion caused by the deformation, to obtain a more stable spectral sensitivity characteristic, and to further enhance the detection response.

[0037]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following description, an example will be described in which radiation is infrared light and readout light is visible light. However, in the present invention, the radiation may be X-rays other than infrared rays, ultraviolet rays, or various other types of radiation. Alternatively, the reading light may be light other than visible light.

[First Embodiment]

FIG. 1 is a view showing a unit pixel (unit element) of an optical readout type radiation detecting apparatus 100 according to a first embodiment of the present invention, and FIG. 1A is a schematic plan view thereof. FIG. 2B is a schematic cross-sectional view taken along line AA ′ in FIG.

The radiation detection apparatus 100 includes a substrate 1 such as a Si substrate as a substrate that transmits infrared rays i, two legs 2 and 3 rising from the substrate 1, and a substrate 1 through the legs 2 and 3. A displacement section 4 supported by the infrared ray absorbing section 5 having an infrared ray absorbing section 5 for absorbing the infrared ray i, and displacing the substrate section 1 with respect to the substrate 1 in response to heat generated by the infrared ray absorbing section 5; A reflecting member 12.

In the present embodiment, both surfaces of the substrate 1 are coated with infrared antireflection films 6 and 7, respectively.
However, these films 6 and 7 need not always be formed.

In FIG. 1, reference numerals 2a and 3a denote contact portions of the legs 2 and 3 with the film 6 on the substrate 1, respectively. The plane portions 2b and 3b of the legs 2 and 3 are each formed in an L shape. The legs 2 and 3 are made of, for example, a SiO film as a material having high heat insulating properties.

The displacement part 4 is composed of two membranes 8 overlapping each other,
9 has two displacement generating portions 10 and 11 respectively. The displacement generating portions 10 and 11 have respective one ends connected to and supported by the tip portions of the flat portions 2b and 3b of the legs 2 and 3, respectively, thereby forming cantilevers. It is supported in a floating state. The film 8 and the film 9 are made of different materials having different expansion coefficients from each other.
1 is the so-called thermal bimorph structure (bi-material elemen
Also called t. ). Therefore, the displacement generating portions 10 and 11 curve upward according to the heat received when the expansion coefficient of the lower film 8 is larger than the expansion coefficient of the upper film 9 and downward when the expansion coefficient is opposite. Tilt. In the present embodiment, the film 8 is composed of a 0.28 μm thick SiN film, and the film 9 is composed of a 0.1 μm thick Al film.

The infrared absorbing section 5 has a characteristic of reflecting a part of the incident infrared light i. The infrared absorbing unit 5 includes a plurality of films 7 stacked one on another in the vertical direction in FIG.
1, 72. These films 71 and 72 have a property of transmitting a part of the infrared rays i. Multiple membranes 7
Each of the members 1 and 72 is formed of a different material from other films stacked adjacent to the film. In the present embodiment, the infrared absorbing section 5 is formed by a 0.28 μm SiN film 71
This is a two-layer film made of a 4 μm SiO film 72 and is formed in a flat plate shape.

As shown in FIG. 1B, in this embodiment, the lower layer is the SiN film 71 and the upper layer is the SiO film 72. However, the present invention is not limited to this. It is needless to say that even a SiN film is within the scope of the present invention.

The combination of materials is not limited to this, as long as it has a property of absorbing a part of the incident infrared light i and transmitting a part of it. For example, a metal oxide film (TiO ₂ , MgO, ZnO, ZrO _2, etc.), a semiconductor thin film (α-Si, CdTe, ZnS, etc.), a metal fluoride film (MgF ₂ , NdF ₃ , CeF ₃ etc.), a chalcogenide glass thin film Etc. can also be used. Further, the respective film thicknesses are not limited to the above values as described later. Further, the number of films constituting the infrared absorbing section 5 is not limited to two.

The infrared absorbing section 5 includes the displacement generating portions 10 and 1
1 is connected to the tip portion. In the present embodiment, the lower SiN film 71 of the infrared absorbing section 5 has a thickness of 0.28 μm.
Since the m m SiN film 8 extends from the displacement generating portions 10 and 11 as it is, the infrared absorbing portion 5 is connected to the tip portions of the displacement generating portions 10 and 11.

The displacement portion 4 is provided with a plate-like member 12 made of an Al film having a thickness of 2000 Å. The member 12 has one portion fixed to the infrared absorbing section 5 via the connection section 13 so that the member 12 is arranged substantially in parallel with the infrared absorbing section 5 at a predetermined interval above the infrared absorbing section 5. In addition, it is arranged so as to cover not only the entire infrared absorbing portion 5 but also a considerably wider range than the infrared absorbing portion 5. In the present embodiment, the member 12 is fixed to the infrared absorbing section 5 in this manner, so that the member 12 is positioned relative to the infrared absorbing section 5 regardless of the displacement of the displacement section 4. It is provided on the displacement part 4 so that the relationship is kept substantially constant.
The connecting portion 13 is formed by extending the Al film forming the member 12 as it is.

The member 12 has an odd number n and an incident infrared ray i.
Λ is the center wavelength of the desired wavelength range₀As the infrared absorbing part
5 in the thickness direction (vertical direction in FIG. 1B) and infrared
The reflection surface of the member 12 as a line reflection portion (the lower surface in FIG. 1B)
Surface), the distance between the infrared absorbing part 5 and the member 12
Direction L (the vertical direction in FIG. 1B) is substantially nλ
₀/ 4. Specifically, for example, wavelength 8
The desired wavelength to absorb infrared rays of up to 12 μm.
If the range is 8 to 12 μm, the center wavelength λ₀Is 10μ
m, the distance L1 is approximately 2.5 μ, where n is 1.
m may be set. Also, for example, the desired wavelength range
Is 3 to 5 μm, the center wavelength λ ₀Is 4 μm
Therefore, n is set to 1 and the distance L1 is set to approximately 1 μm.
Just do it. However, the distance L1 is limited to these examples.
It is not something to be done.

The member 12 has a thickness of 20 as described above.
It is an infrared reflecting portion made of an Al film having a thickness of 00 angstroms and substantially totally reflecting infrared rays i. Also, member 1
Reference numeral 2 denotes a readout light reflecting portion that reflects the received readout light j as a displacement readout member. That is, in the present embodiment, the infrared reflecting section is also used as the reading light reflecting section. It is also possible to form a reflection film as an infrared reflection portion on the surface of the member 12 facing the radiation absorbing portion 5 and use the member 12 as a readout light reflection portion only.

As can be seen from the above description, in the present embodiment, the displacement portion 4 is composed of the displacement generating portions 10 and 11, the infrared absorbing portion 5, and the member 12 which also serves as the infrared reflecting portion and the reading light reflecting portion. It is configured. However, the present invention is not limited to this.

As described above, the infrared absorbing section 5 according to the present embodiment has a two-layer film. As a result, the wavelength range of the infrared light to be absorbed is widened, the infrared absorptivity is increased, and sensitivity is improved.

The present inventors have confirmed this point by experiments. Some of the experimental results are shown in FIGS.
As a measurement sample, an Al film as an infrared reflecting portion was formed on a silicon substrate, and a resist (SCF) film was formed thereon as a sacrificial layer for forming an interval, and the resist had a square shape in plan view. An opening for connecting portion exposing the Al film is formed at the four apexes, and S
An iN film and a SiO film (a SiO film was not formed depending on a measurement sample) were formed in this order, and a SiN film and a S film were formed.
the iO film is patterned into a square shape slightly larger than the square shape, and then the resist is removed;
Was prepared. Thereby, in each measurement sample, an infrared absorbing portion composed of a two-layer film of an Al film as an infrared reflecting portion and a SiO film and a SiN film (the SiO film is on the Al film side) or an infrared absorbing portion composed of a single-layer film of a SiN film. The parts were opposed to each other with an interval corresponding to the thickness of the resist film. However,
After removing the resist and completing the measurement sample, the infrared absorbing portion was not completely flat but warped. In each measurement sample, the thickness of the resist was 2.4 μm,
The thickness of the SiN film was 0.28 μm, and Si
The thickness of the O film was changed, and the thickness was set to 0 μm (that is, the SiO film was not formed and the infrared absorbing portion was only the SiN film), 0.08 μm, 0.16 μm, and 0.24 μm.

Then, for each measurement sample, infrared rays of each wavelength were incident from the SiN film side to the Al film side, and the absorptance in the infrared absorption part was measured for each wavelength. 2 to 5 show that the thickness of the SiO film is 0 μm and 0.08 μm, respectively.
It is a graph which shows the relationship between absorptivity and wavelength of a sample of m, 0.16 micrometer, and 0.24 micrometer.

If the infrared absorbing portion was a single-layer SiN film, the absorption characteristics had a peak between 11 and 12 μm as shown in FIG. However, if a two-layer film of SiO is used, as shown in FIGS. 3 to 5, the wavelength band in which the absorptance exceeds 90% in the wavelength region of 8 to 12 μm increases. The absorptance is 1 in the entire wavelength region of 8 to 12 μm.
Ideally, it is 00%, but if the infrared absorbing portion is formed of a two-layer film, the ideal absorption characteristics are approached.
Therefore, it is understood that the absorptivity (absorptance integrated with wavelength) in the entire wavelength band is increased, and the sensitivity in this wavelength band is improved. Further, in the above-described experimental example, the thickness of the SiO film was changed from zero to 0.24 μm, but as long as it was a two-layer film of the SiN film and the SiO film,
Regardless of the thickness of the SiO film, the improvement of the absorption rate
Understood.

Although not shown in the drawings, in the radiation detecting apparatus 100 according to the present embodiment, the displacement part 4 and the legs 2 and 3 are used as unit elements (pixels), and the pixels are one-dimensionally formed on the substrate 1. They are arranged two-dimensionally.

The radiation detection apparatus 100 according to the present embodiment
Can be manufactured using semiconductor manufacturing techniques such as formation and patterning of a film and formation and removal of a sacrificial layer, and can be manufactured by, for example, the following method.

Although not shown in the drawing, first, both surfaces of the Si substrate 1 are coated with infrared antireflection films 6 and 7,
A resist as a sacrificial layer is applied on the film 6. Openings corresponding to the contact portions 2a and 3a of the legs 2 and 3 are formed in the resist by photolithography. Next, S
After depositing the iO film by the P-CVD method or the like, the legs 2 and 3 are formed by patterning by the photolithography etching method. Then, after depositing the SiN film by a P-CVD method or the like, the SiN film is patterned by a photolithographic etching method,
The film 8 and the lower film 71 of the infrared absorbing section 5 are formed. Next, after depositing the Al film by a vapor deposition method or the like, the Al film is patterned by a photolithographic etching method to form the film 9.
Further, after depositing the SiO film by a P-CVD method or the like,
The upper layer film 72 of the infrared absorption section 5 is formed by patterning by photolithography. A resist as a sacrificial layer is applied again on the entire surface of the substrate in this state. next,
An opening corresponding to the connection portion 13 is formed in the resist by photolithography. Then, after depositing the Al film to be the member 12 and the connection portion 13 by a vapor deposition method or the like,
The member 1 is patterned by photolithographic etching.
2 shape. Finally, the resultant is divided into chips by dicing or the like, and the resist as a sacrificial layer is removed by ashing or the like. Thereby, the radiation detection device 100 shown in FIG. 1 is completed.

In the radiation detecting apparatus 100 according to the present embodiment, when the infrared ray i enters from below, the incident infrared ray i
Is partially absorbed by the infrared absorbing section 5, and a part of the remaining is transmitted through the infrared absorbing section 5 and guided to the member 12. A part of the rest is a lower film 71 or an upper film 72 of the infrared absorbing portion 5.
Is reflected by Therefore, an interference phenomenon occurs between the infrared light reflected by the member 12 and the infrared light reflected by the respective films 71 and 72 of the infrared absorbing unit 5.

The distance L1 between the center in the thickness direction of the infrared absorbing section 5 and the reflecting surface of the member 12 as the infrared reflecting section is:
Here, the thickness is set to 2.5 μm or 1 μm. This is wavelength 1
This is because the sensitivity is almost maximized around 0 μm or the wavelength of 4 μm. In the present embodiment, the infrared absorbing section 5 has a lower film 71 and an upper film 72, and each film 7
The difference in the optical path length between the infrared rays reflected at 1, 72 and the infrared rays reflected at the member 12 is different. For this reason, the maximum absorption wavelengths of both are shifted, and the infrared absorptivity of the infrared absorbing section 5 is improved as compared with the case where the infrared absorbing section 5 is formed of a single layer film.

Then, the heat generated in the infrared absorbing portion 5 is transmitted to the displacement generating portions 10 and 11, and the displacement generating portions 10 and 11 constituting the cantilever are curved downward and inclined in accordance with the heat. For this reason, the member 12 is inclined with respect to the surface of the substrate 1 by an amount corresponding to the amount of the incident infrared light i while maintaining the relative positional relationship (that is, the interval L1) with the radiation absorbing portion 5. Become. Therefore, the readout light j incident on the member 12 from above is reflected in a direction corresponding to the amount of the incident infrared light i.

In the present embodiment, the infrared absorbing section 5
Is provided in the displacement part 4, the heat generated in the infrared absorbing part 5 is efficiently conducted to the displacement generating parts 10 and 11 in the displacement part 4, and the detection sensitivity is enhanced from this point as well.

Further, according to the present embodiment, the displacement portion 4
Regardless of the displacement of the member 12
Since the relative positional relationship between the infrared ray and the infrared absorbing section 5 is kept substantially constant, stable spectral sensitivity characteristics can be obtained.

Further, according to the present embodiment, since the member 12 is also used as an infrared reflecting portion and a reading light reflecting portion, the structure can be simplified and provided at a low cost.

Here, the infrared absorbing portion 5 is a two-layer film made of different materials (SiO film and SiN film), but is not limited to this. Three or more layers of different materials may be used. In this case, the same substance may be used in a plurality of layers unless the same substance is directly stacked. For example, the intermediate layer may be a SiO film, and the upper and lower layers may be SiN films.

Here, an example of an imaging device using the radiation detection device 100 according to the present embodiment will be described with reference to FIG. FIG. 6 is a schematic configuration diagram showing the imaging apparatus.

This imaging apparatus includes, in addition to the radiation detection apparatus 100 described above, a readout optical system and a two-
The infrared ray i from the two-dimensional CCD 20 and the heat source 21 as an observation target is collected and the infrared ray
And an infrared imaging lens 22 that forms an infrared image of the heat source 21 on the surface where the light is distributed.

In this imaging apparatus, the readout optical system includes an LD (laser diode) 23 as readout light supply means for supplying readout light, and reads out the readout light from the LD23 to all pixels of the radiation detection apparatus 100. 1st lens system 2 which leads to member 12 as a reading light reflection part of
4, a light beam limiting unit 25 for selectively passing only a desired light beam among the light beams of the read light reflected by the members 12 of all the pixels after passing through the first lens system 24,
A second lens system 26 that forms a conjugate position with the reflector 12 of each pixel in cooperation with the first lens system 24 and guides the light beam that has passed through the light beam restricting unit 25 to the conjugate position. ing. The light receiving surface of the CCD 20 is arranged at the conjugate position, and the members 12 of all the pixels and the plurality of light receiving elements of the CCD 20 are optically conjugated by the lens systems 24 and 26.

The LD 23 is disposed on one side (the right side in FIG. 6) with respect to the optical axis O of the first lens system 24, and supplies the reading light so that the reading light passes through the one side area. I do. In this example, the LD 23 is the first lens system 2
4 is disposed near the focal plane on the second lens system 26 side, so that the readout light passing through the first lens system 24 becomes a substantially parallel light beam and irradiates the members 12 of all the pixels. In order to increase the contrast of the optical image on the CCD 20, a readout light stop may be provided in front of the LD.
In this example, the radiation detecting apparatus 100 has the surface of the substrate 1 (in this example, the surface of the substrate 1 is parallel to the surface of the member 12 when infrared rays from the target object (heat source 21) do not enter).
Are arranged so as to be orthogonal to the optical axis O. However,
It is not limited to such an arrangement.

The light beam restricting section 25 is arranged such that a portion for selectively passing only the desired light beam is on the other side (left side in FIG. 6) with respect to the optical axis O of the first lens system 24. It is configured as follows. In the present example, the light flux limiting unit 25
Is composed of a light shielding plate having an opening 25a, and is configured as an aperture stop. In this example, when infrared rays from the target object are not incident on the infrared absorbing unit 5 of any pixel and the surfaces of the members 12 of all pixels are parallel to the surface of the substrate 1, the members of all pixels The light beam reflected at 12 (each member 1
The light beam bundle restricting unit 25 is arranged so that the position of the light condensing point where the individual light beam bundle reflected by the light beam 2 is condensed by the first lens system 24 substantially coincides with the position of the opening 25a.
The size of the opening 25a is determined so as to substantially match the size of the cross section of the light beam at the converging point. However, it is not limited to such an arrangement and size.

According to the imaging device shown in FIG.
The light beam 31 of the readout light emitted from the light beam enters the first lens system 24 and becomes a substantially parallel light beam 32. Next, the substantially collimated light beam 32 is applied to the radiation detection device 100.
Are incident on the members 12 of all the pixels at a certain angle with respect to the normal line of the substrate 1.

On the other hand, the heat source 21
Is collected, and an infrared image of the heat source 21 is formed on the surface of the radiation detecting apparatus 100 where the infrared absorbing portions 5 are distributed. As a result, infrared rays enter the infrared absorbing section 5 of each pixel of the radiation detection device 100. For this reason, by the above-described operation, the member 12 of each pixel causes the substrate 1 by an amount corresponding to the amount of infrared light incident on the corresponding infrared absorbing portion 5.
Will be inclined with respect to the plane.

Now, it is assumed that no infrared rays from the target object are incident on the infrared absorbing portions 5 of all the pixels, and the members 12 of all the pixels are parallel to the substrate 1. The light beam 32 incident on the members 12 of all the pixels is reflected by these members 12 to become a light beam 33, and is again incident on the first lens system 24 from the side opposite to the LD 23 side and condensed. Luminous flux 3
The light beam is condensed at the position of the opening 25a of the light beam restricting portion 25 arranged at the position of the light condensing point of the light beam 34. As a result, the condensed light beam 34 passes through the opening 25a to become a divergent light beam 35 and enters the second lens system 26. The divergent light beam 35 incident on the second lens system 26 becomes, for example, a substantially parallel light beam 36 by the second lens system 26 and is incident on the light receiving surface of the CCD 20. Here, since the member 12 of each pixel and the light receiving surface of the CCD 20 are conjugated by the lens systems 24 and 26, an image of each member 12 is formed on each corresponding portion on the light receiving surface of the CCD 20, and the entire image is formed. As a result, an optical image which is a distribution image of the members 12 of all pixels is formed.

Now, it is assumed that a certain amount of infrared light is incident on the infrared absorbing portion 5 of a certain pixel, and the member 12 of the pixel is inclined with respect to the surface of the substrate 1 by an amount corresponding to the amount of the incident light. The individual light beams incident on the member 12 in the light beam 32 are
Since the light is reflected by the member 12 in a direction different by the amount of the tilt, after passing through the first lens system 24, the light condensing point (that is, the opening 25a) has an amount corresponding to the amount of the tilt.
Is condensed at a position shifted from the position, and is blocked by the light flux limiting unit 25 by an amount corresponding to the amount of inclination. Therefore, the light amount of the image of the member 12 in the entire optical image formed on the CCD 20 decreases by an amount corresponding to the amount of inclination of the member 12.

Therefore, the optical image formed by the read light formed on the light receiving surface of the CCD 20 is
Is a reflection of the infrared image incident on. This optical image is captured by the CCD 20. The optical image may be observed with the naked eye using an eyepiece or the like without using the CCD 20.

Needless to say, the configuration of the readout optical system is not limited to the configuration described above.

Although the above is an example of an imaging device, in FIG. 6, a radiation detection device having only a single pixel (element) is used as the radiation detection device 100, and a two-dimensional CCD 2 is used.
If a photodetector having only a single light receiving section is used instead of 0, a detection device as a so-called point sensor for infrared rays can be configured. This applies to each of the embodiments described later.

[Second Embodiment]

FIG. 7 is a view showing a unit pixel (unit element) of an optical readout type radiation detecting apparatus 200 according to the second embodiment of the present invention, and FIG. 7 (a) is a schematic plan view thereof. FIG. 7B is a schematic sectional view taken along line BB ′ in FIG. 7A. The difference from the radiation detection apparatus 100 according to the first embodiment is that the infrared absorption unit 205 has two individual infrared absorption units that are arranged at an interval in the vertical direction in FIG. 7B. is there. In the present embodiment, the lower individual infrared absorbing section is constituted by a single layer film 271, and the upper individual infrared absorbing section is constituted by a single layer SiN film 272. The other points are the same as those of the first embodiment, and a duplicate description will be omitted.

The infrared absorbing section 205 is provided with the displacement generating portion 1
A single-layer SiN film 271 as a lower individual infrared absorbing portion extending directly from 0 and 11 and fixed to the SiN film 271 via four connection portions 273 and provided above the SiN film 271 with a space therebetween. And a 0.28 μm thick SiN film 272 as an upper individual infrared absorbing portion. The upper SiN film 272 has an infrared ray i.
Is fixed via the connecting portion 13,
The members 12 are arranged above the SiN film 272 with an interval.

The center in the thickness direction of the SiN film 271 as the lower individual infrared absorbing portion and the member 1 as the infrared reflecting portion
The distance L2 in the vertical direction in FIG. 7B between the reflective surface (lower surface) 2 and the reflective surface (lower surface) of FIG. The vertical distance L3 in FIG. 7B between the center in the thickness direction of the SiN film 272 as the upper individual infrared absorbing portion and the reflecting surface (lower surface) of the member 12 as the infrared reflecting portion is a wavelength. The thickness was set to approximately 1 μm in order to increase the absorptance centered on 4 μm infrared rays. Due to such a configuration, 3 to 3 are called as atmospheric windows.
The radiation detection device has sensitivity in any of two separate infrared wavelength bands of 5 μm and 8 to 12 μm. However, the wavelength range is not limited to these examples.

Here, the upper individual infrared absorbing portion and the lower individual infrared absorbing portion are each constituted by a single-layer film, but the present invention is not limited to this. Each of the upper individual infrared absorbing section and the lower individual infrared absorbing section
A plurality of films made of different substances may be arranged as in the infrared absorbing section 5 according to the embodiment. By arranging a plurality of films on each of the upper individual infrared absorbing section and the lower individual infrared absorbing section, the infrared absorptance is further improved. Further, the number of the individual infrared absorbing portions is not limited to two, and three or more individual infrared absorbing portions may be arranged at intervals.

In this embodiment, for example,
The difference between the distances L2 and L3 may be made sufficiently small while leaving an interval between the iN films 271 and 272. In this case, it differs from the first embodiment in that there is an interval between the two films 271 and 272, but the distances L2 and L3 are both approximately 2.5 μm, or both are approximately 1 μm.
By doing so, substantially the same operation and effect as in the first embodiment can be obtained.

[Third Embodiment]

FIG. 8 is a schematic plan view showing a unit pixel (unit element) of an optical readout type radiation detecting apparatus 101 according to the third embodiment of the present invention. FIG. 9 shows C-
FIG. 4 is a schematic cross-sectional view along the line C ′. 8 and 9, the same or corresponding elements as those in FIG. 1 are denoted by the same reference numerals, and redundant description will be omitted.

The radiation detecting apparatus 101 is basically different from the radiation detecting apparatus 100 shown in FIG. 1 only in the following points.

In the radiation detecting apparatus 101, the member 12
Is a falling portion (or a rising portion) 1 formed so as to fall from the flat portion 12a over the whole (or a part) of a peripheral portion of the flat portion 12a parallel to the substrate 1.
2b, and a horizontal portion 12c slightly extending laterally outward from a lower portion of the falling portion 12b. Horizontal part 1
2c may be removed. Since the flat portion 12a is reinforced by the falling portion 12b, the thickness of the flat portion 12a can be reduced while ensuring the desired strength of the flat portion 12a. For this reason, the heat capacity of the member 12 can be reduced while preventing deformation due to insufficient strength of the member 12. As a result, a more stable spectral sensitivity characteristic can be obtained by preventing the change in the interval L1 caused by the deformation, and the responsiveness of detection can be further enhanced.

In the radiation detecting apparatus 101, the infrared absorbing portion 5 is formed of Si which is a lower film of the displacement generating portions 10 and 11.
SiN film 71 and SiO film 72 formed separately from N film 8
It is composed of Then, the infrared absorbing unit 5 is arranged as shown in FIG.
As shown in (1), the upper film 72 is formed so as to cover the edge portion (the surface along the thickness direction) of the lower film 71 over at least a part of the peripheral portion of the plane portion.
Reinforced.

Further, in the radiation detecting apparatus 101, the leg portion 2 is formed so as to fall from the flat portion 2b over the whole (or a part of) the peripheral portion of the flat portion 2b parallel to the substrate 1. Falling part 2c and falling part 2c
A horizontal portion 2d slightly extending laterally outward from the lower part of the
have. The horizontal portion 2d may be removed.
Since the flat portion 2b is reinforced by the falling portion 2c, the desired strength of the flat portion 2b is ensured while the flat portion 2b is secured.
Can be made thinner. For this reason, the heat insulation of the leg part 2 can be improved.

According to the present embodiment, in addition to the advantages described above, the same advantages as in the first embodiment can be obtained.

[Fourth Embodiment]

FIG. 10 is a schematic sectional view showing a unit pixel (unit element) of an optical readout type radiation detecting apparatus 103 according to a fourth embodiment of the present invention, and corresponds to FIG. ing. 10, elements that are the same as elements in FIG. 1 or that correspond to elements in FIG. 1 are given the same reference numerals, and overlapping descriptions are omitted.

The radiation detector 103 differs from the radiation detector 100 shown in FIG. 1 only in the following points.

In the radiation detection apparatus 103, the member 12 in FIG. 1 is removed, and instead, the mask (light shield) 40 for masking the readout light j is opposed to the infrared absorption section 5 with the above-mentioned interval L1. The infrared light reflecting portion 41 formed on the mask 40, the read light half mirror portion 42 provided at the tip of the infrared absorbing portion 5, and the film 6 formed so as to face the read light half mirror portion 42. The read-out light reflection part 43 is added. In addition,
The infrared absorbing section 5 includes a SiN film 81 extending from the displacement generating portions 10 and 11, and a SiO film 82 laminated thereon.

The mask 40 has an opening 40a in a region corresponding to the read light half mirror portion 42, and masks light other than interference light emitted from the half mirror portion 42 in the irradiated read light j. The mask 40 is made of, for example, a film of gold black, platinum black, or the like.

The infrared reflecting section 41 is made of an Al film. The read light half mirror portion 42 is made of a SiO film (transparent to visible light) and a titanium or the like which is very thinly deposited on the SiO film by a sputtering method or the like so as to obtain a desired reflectance. And a metal layer.

When the reading light j enters the half mirror section 42, a part of the reading light j is
The remaining read light j that has entered the half mirror section 42 is reflected by the half mirror section 42, passes through the half mirror section 42, is reflected by the total reflection mirror 43, and returns to the half mirror section 4 again.
2 is incident from the lower surface. Part of the readout light that has re-entered the half mirror unit 42 from the lower surface is transmitted through the half mirror unit 42 and becomes transmitted light. There is an optical path length difference between the transmitted light and the reflected light, which corresponds to twice the distance d between the half mirror section 42 and the total reflection mirror 43. Therefore,
Interference occurs between the reflected light and the transmitted light according to the optical path length difference, and the reflected light and the transmitted light interfere according to the optical path length difference (accordingly, according to the displacement of the displacement unit 4). The light is emitted from the half mirror unit 42 as interference light having a high intensity.

In this embodiment, since the radiation reflection portion 41 is fixed to the substrate 1 via the mask 40, the distance L1 changes when the displacement portion 4 is displaced, so that the stability of the spectral sensitivity characteristic is improved. Is inferior to the first embodiment, but the other advantages are the same as those of the first embodiment.

The radiation reflection section 41 according to the present embodiment.
The readout optical system itself that can be used together with
It is known as disclosed in FIG. 16 of JP-A-53447.

[Fifth Embodiment]

FIG. 11 is a diagram showing a unit pixel (unit element) of a capacitance type radiation detecting apparatus 104 according to a fifth embodiment of the present invention, and FIG.
FIG. 11B is a schematic cross-sectional view along the line DD ′ in FIG. 11, elements that are the same as elements in FIG. 1 or that correspond to elements in FIG. 1 are given the same reference numerals, and redundant descriptions are omitted.

The radiation detector 104 differs from the radiation detector 100 shown in FIG. 1 only in the following points.

In this radiation detecting device 104, the Si substrate 1
Are not coated with infrared antireflection films 6 and 7.

Further, in the radiation detecting device 104, a flat plate-shaped member 50 is connected to the distal end portions of the displacement generating portions 10, 11 instead of the infrared absorbing portion 5 in FIG. The member 50 is configured by the Al film 9 extending from the displacement generating portions 10 and 11 as it is. This member 50
Is a movable electrode section as a displacement readout member used to obtain a change in capacitance according to the displacement generated in the displacement section 4. Further, the member 50 is an infrared reflecting portion that substantially totally reflects the infrared light i. That is, in the present embodiment, the infrared reflecting section is also used as the movable electrode section. In addition, a reflection film as an infrared reflection portion may be formed on a surface of the member 50 facing an infrared absorption portion 51 described later, and the member 50 may be used only as a movable electrode portion.

The infrared absorbing section 51 is composed of a SiN film 72 and a SiO film 71 fixed on the member 50. And
In the radiation detection device 104, the infrared absorption unit 51 is connected to the connection unit 52.
By being fixed to the member 50 via the member 50, the member 50 is arranged substantially parallel to the member 50 at an interval above the member 50. Thereby, the infrared absorbing section 51 is provided in the displacement section 4. In the present embodiment, the infrared absorbing portion 51 is fixed to the member 50 in this manner, so that the member 50 is positioned relative to the member 50 and the infrared absorbing portion 51 regardless of the displacement of the displacement portion 4. It is provided on the displacement part 4 so that the relationship is kept substantially constant. Note that the distance between the center in the thickness direction of the infrared absorbing section 51 and the reflecting surface (the upper surface in FIG. 11B) of the member 50 as the infrared reflecting section is set to the above-described distance L1.

The substrate 1 has a member 50 as a movable electrode section.
A fixed electrode portion 53 made of a metal film is provided so as to face. The upper surface of the fixed electrode unit 53 may be covered with a dielectric film if necessary. On the substrate 1, a diffusion layer 54 electrically connected to the fixed electrode portion 53 is formed below the fixed electrode portion 53. Is formed with a diffusion layer 55. An Al film 9 and a diffusion layer 5 are formed on the legs 2 and 3, respectively.
5 (finally, between the member 50 as the movable electrode portion and the diffusion layer 55) is formed. Openings are formed in the contact portions 2a and 3a, respectively, and the wiring layer 56 is electrically connected to the diffusion layer 55 through these openings.

As can be seen from the above description, in the present embodiment, the displacement portion 4 is constituted by the displacement generating portions 10 and 11, the infrared absorbing portion 51, and the member 50 which also serves as the infrared reflecting portion and the movable electrode portion. Have been.

According to the radiation detecting device 104, when the infrared light i is incident from above, the infrared absorbing portion 51 absorbs the infrared light i by the same interference phenomenon as that of the radiation detecting device 100 according to the first embodiment, thereby causing heat. Occurs. This heat is transmitted to the displacement generating portions 10 and 11, and the displacement generating portions 10 and 11 constituting the cantilever are curved downward and inclined in accordance with the heat. For this reason, the relative positional relationship between the member 50 and the infrared absorbing unit 51 (that is, the interval L1).
While maintaining the angle, the surface of the substrate 1 is inclined by an amount corresponding to the amount of the incident infrared light i, and the distance between the member 50 as the movable electrode portion and the fixed electrode portion 53 changes. This allows
The value of the capacitance between the member 50 and the fixed electrode 53 changes, and the amount of incident infrared rays can be detected as a change in the capacitance from between the diffusion layers 54 and 55. Although not shown in the drawings, the diffusion layers 54 and 55 are connected to a read circuit for reading out the capacitance.

The displacement section 4, the legs 2, 3 and the fixed electrode section 53 are used as unit elements (pixels), and the pixels are arranged one-dimensionally or two-dimensionally on the substrate 1. Provides an infrared image signal.

According to this embodiment, the same advantages as those of the first embodiment can be obtained.

The embodiments of the present invention have been described above, but the present invention is not limited to these embodiments. For example, each of the above-described embodiments is an example in which an optical cavity using an infrared absorbing portion formed by a plurality of films is applied to an optical reading type or a capacitance type infrared detecting device, but is not limited thereto. , A bolometer, an infrared detector using a pyroelectric body, or the like.

[0112]

As described above, according to the present invention,
Both detection sensitivity and detection responsiveness can be increased.

[Brief description of the drawings]

FIG. 1 is a diagram showing a unit pixel of a radiation detection apparatus according to a first embodiment of the present invention, FIG. 1 (a) is a schematic plan view, and FIG. 1 (b) is a view in FIG. FIG. 3 is a schematic cross-sectional view along the line AA ′.

FIG. 2 is a graph showing the relationship between the absorptance and the wavelength obtained by experiments on a predetermined measurement sample.

FIG. 3 is a graph showing the relationship between the absorptance and the wavelength obtained by experiments on other measurement samples.

FIG. 4 is a graph showing the relationship between the absorptance and the wavelength obtained by experiments on still another measurement sample.

FIG. 5 is a graph showing the relationship between the absorptance and the wavelength obtained by experiments on still another measurement sample.

6 is a schematic configuration diagram showing an example of an imaging device using the radiation detection device shown in FIG.

FIG. 7 is a diagram showing a unit pixel (unit element) of an optical readout type radiation detection apparatus according to a second embodiment of the present invention;
FIG. 7A is a schematic plan view, and FIG. 7B is FIG.
It is an outline sectional view along the BB 'line in the inside.

FIG. 8 is a schematic plan view showing a unit pixel (unit element) of an optical readout type radiation detection apparatus 101 according to a third embodiment of the present invention.

FIG. 9 is a schematic sectional view taken along line CC ′ in FIG. 8;

FIG. 10 is a schematic sectional view showing a unit pixel of a radiation detection device according to a fourth embodiment of the present invention.

11A and 11B are diagrams showing a unit pixel of a radiation detection apparatus according to a fifth embodiment of the present invention, wherein FIG. 11A is a schematic plan view, and FIG. FIG. 4 is a schematic cross-sectional view along the line DD ′.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Substrate 2, 3 Leg part 4 Displacement part 5, 51 Infrared absorption part 10, 11 Displacement generation part 12 Member which also serves as reading light reflection part and infrared reflection part 41 Infrared reflection part 42 Reading light half mirror part 43 Reading light reflection part Reference Signs List 50 Member serving also as movable electrode and infrared reflecting portion 53 Fixed electrode 100, 101, 103, 200 Radiation detector

Claims (8)

[Claims] 1. A radiation detecting apparatus having a radiation absorbing section that absorbs radiation, wherein the radiation absorbing section has a characteristic of reflecting a part of incident radiation, and is spaced apart from the radiation absorbing section by a predetermined distance. A radiation reflecting portion that is disposed to substantially totally reflect the radiation, the radiation absorbing portion includes a plurality of films stacked on each other in the direction of the predetermined interval, and each of the plurality of films is A radiation detection device, wherein the radiation detection device is formed of a material different from that of another film stacked adjacently. 2. When n is an odd number and λ ₀ is the center wavelength of a desired wavelength range of the radiation, the predetermined distance between the center of the radiation absorbing portion in the thickness direction and the reflecting surface of the radiation reflecting portion is defined. distance direction, the radiation detecting apparatus according to claim 1, wherein it is approximately nλ _0/4. 3. A radiation detecting apparatus having a radiation absorbing portion for absorbing radiation, wherein the radiation absorbing portion has a characteristic of reflecting a part of incident radiation, and is spaced apart from the radiation absorbing portion by a predetermined distance. A radiation reflection unit disposed to substantially totally reflect the radiation, the radiation absorption unit includes a plurality of individual radiation absorption units disposed at intervals in the direction of the predetermined interval, and the plurality of individual radiation absorption units; Each of the radiation absorbing sections has a single film or a plurality of films stacked in the direction of the predetermined interval. 4. At least one of the plurality of individual radiation absorbing portions has a plurality of films stacked on each other in the direction of the predetermined interval, and each of the plurality of films is 4. The radiation detection apparatus according to claim 3, wherein the radiation detection apparatus is formed of a different material from other films stacked adjacent to the film. 5. odd n, the center wavelength of the desired first wavelength region of the radiation as lambda _1, at least one of the thickness direction of the individual radiation absorber center of the plurality of individual radiation absorbing portion It said radiation between the reflection surface of the reflection portion, the distance in the direction of the predetermined intervals, the radiation detecting apparatus according to claim 3 or 4, wherein it is approximately n [lambda _1/4. 6. When m is an odd number, and λ ₂ is a center wavelength of a desired second wavelength range of the radiation, a thickness direction of at least one other individual radiation absorbing section of the plurality of individual radiation absorbing sections is defined. between the center and the reflective surface of the radiation reflection portion, the distance in the direction of the predetermined intervals, the radiation detecting apparatus according to claim 5, characterized in that the approximately mλ _2/4. 7. The radiation detecting apparatus according to claim 1, wherein each of the films included in the radiation absorbing part partially transmits infrared light. And a displacement part supported by the base, wherein the displacement part has the radiation absorbing part, and is displaced with respect to the base in response to heat generated in the radiation absorbing part. The radiation reflecting portion is provided on the displacement portion so that the relative positional relationship between the radiation reflecting portion and the radiation absorbing portion is kept substantially constant regardless of the displacement of the displacement portion. The radiation detection device according to claim 1, wherein