Bolometer and bolometer array

Abstract

To provide a bolometer which can reduce the electric resistance between electrodes.SOLUTION: The bolometer includes: a first electrode; a second electrode, which is a meander region being formed between the second electrode and the first electrode; and a sensor part having a carbon nono-tube film electrically connected to the first electrode and to the second electrode in the meander region.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to bolometers and bolometer arrays.

Background Art

[0002] It is widely known that bolometers are used to detect infrared rays. For example, Patent Document 1 discloses a bolometer including a pair of electrodes and a bolometer film that is a carbon nanotube film.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the bolometer disclosed in Patent Document 1, a carbon nanotube film is connected to a pair of electrodes. For this reason, the electrical resistance between the electrodes may increase.

[0005] An object of the present disclosure is to provide a bolometer and a bolometer array that solve the above problems.

Means for Solving the Problems

[0006] A bolometer according to one aspect of the present disclosure includes a first electrode, a second electrode provided with respect to the first electrode with a meandering inter-electrode region therebetween, and a sensor unit including a carbon nanotube film electrically connected to the first electrode and the second electrode in the inter-electrode region.

Effects of the Invention

[0007] According to the above aspect, the electrical resistance between the electrodes can be reduced.

Brief Description of the Drawings

[0008]

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Embodiments for Carrying Out the Invention

[0009] Hereinafter, various embodiments according to the present disclosure will be described with reference to the drawings.

[0010] <First Embodiment> Hereinafter, an embodiment of a bolometer according to the present disclosure will be described.

[0011] (Configuration of Bolometer) The bolometer 9 is a device for detecting infrared rays. For example, the wavelength band of the infrared rays detected by the bolometer 9 may include 1 to 100 μm. For example, the wavelength band of the infrared rays detected by the bolometer 9 may include the terahertz band. The bolometer 9 is a device that constitutes each pixel of a bolometer array 99 applied to, for example, an uncooled infrared sensor. As shown in FIG. 1, the bolometer array 99 includes a plurality of bolometers 9 and a substrate 8. A plurality of bolometers 9 are provided side by side in the plane on the substrate 8. For example, the substrate 8 may include a readout integrated circuit for reading out a change in the electrical resistance value from each bolometer 9. For example, the bolometer array 99 may include a sealing member that seals the plurality of bolometers 9 so that the peripheries of the plurality of bolometers 9 are in a vacuum state.

[0012] As shown in FIG. 2, each bolometer 9 is disposed on the substrate 8. The bolometer 9 includes a first electrode 1, a second electrode 2, a sensor portion 3, a wiring portion 4, and a protective film 5. As shown in FIG. 3, each component of the bolometer 9 has a point-symmetrical structure about a central axis AX extending in the Z direction.

[0013] The lower limit of the element size of each bolometer 9 is defined by the limit size in the microfabrication process in each bolometer 9 including the meander shape. The upper limit of the element size of each bolometer 9 is defined by the limit size for maintaining the hollow structure. As such an element size, for example, the size of each bolometer 9 in each of the X direction and the Y direction is preferably, for example, 10 μm to 50 μm.

[0014] In the present disclosure, the first direction D1 is also referred to as the X direction, the second direction D2 is also referred to as the Y direction, and the stacking direction DS is also referred to as the Z direction. The first direction D1, the second direction D2, and the stacking direction DS intersect with each other. For example, the first direction D1, the second direction D2, and the stacking direction DS may be orthogonal to each other. For example, the XY plane may be a horizontal plane, and the stacking direction DS may be the vertical direction.

[0015] In the present embodiment, the outer peripheral shape of the bolometer 9 is a quadrilateral having a first angle C1, a second angle C2, a third angle C3, and a fourth angle C4 in this order when viewed from the Z direction. At this time, the outer peripheral shape may be a rectangle, or may further be a square.

[0016] (Configuration of the first electrode) The first electrode 1 is an electrode for passing a current between the second electrode 2 via the sensor unit 3. The first electrode 1 is provided on the first angle C1 and second angle C2 sides with respect to the second electrode 2 in the second direction D2. The first electrode 1 includes a first base end 11 and a plurality of first extending portions 12. For example, in the first electrode 1, the first base end 11 and the plurality of first extending portions 12 may be an integral pattern. For example, the first electrode 1 may include nine first extending portions 12.

[0017] The first electrode 1 is formed of a conductive material such as aluminum, copper, gold, or TiAlV.

[0018] The first base end 11 is provided on the first angle C1 and second angle C2 sides with respect to the central axis AX in the second direction D2. The first base end 11 extends in the first direction D1 while bending once in the second direction D2 so as to avoid the second angle C2.

[0019] The size of the first base end 11 may be any size as long as it is within an appropriate range in consideration of both the possibility of microfabrication and effectively reducing resistance. For example, the width of the first base end 11 is 1% to 40%, preferably 3% to 20% of the element size of the bolometer 9.

[0020] Each of the plurality of first extending portions 12 protrudes from the first base end 11 in the second direction D2. For example, the plurality of first extending portions 12 may be arranged in parallel at equal intervals in the Y direction.

[0021] The size of each first extending portion 12 may be any size within an appropriate range considering both microfabrication feasibility and effectively reducing resistance. Also, the number of the plurality of first extending portions 12 may be any number within an appropriate range considering both microfabrication feasibility and effectively reducing resistance. For example, the width of each first extending portion 12 is 0.2 μm to 20 μm, preferably 0.2 μm to 1 μm. For example, the length of each first extending portion 12 is 20% to 99% of the element size of the bolometer 9, preferably 30% to 70%. For example, the number of the plurality of first extending portions 12 is 2 to 30, preferably 5 to 15.

[0022] (Configuration of the second electrode) The second electrode 2 is an electrode for flowing a current between the first electrode 1 via the sensor portion 3. The second electrode 2 is separated from the first electrode 1 in the XY plane. The second electrode 2 is provided on the third angle C3 and fourth angle C4 sides with respect to the first electrode 1 in the second direction D2. The second electrode 2 includes a second base end 21 and a plurality of second extending portions 22. For example, in the second electrode 2, the second base end 21 and the plurality of second extending portions 22 may be of an integral pattern. For example, the second electrode 2 may include nine second extending portions 22.

[0023] The second electrode 2 is provided separated from the first electrode 1 with the electrode region AA interposed therebetween. The electrode region AA is meandering in the XY plane. In the present disclosure, "meandering" means having a wavy shape. This includes extending while undulating, and in the present disclosure, it is also referred to as "extending in a meandering shape". For example, the region AA between the electrodes extends in the first direction D1 while repeating a bend from one side to the other side of the second direction D2 and a bend from the other side to one side of the second direction D2 at the tip extending in the second direction D2.

[0024] The second electrode 2 is formed of a conductive material such as aluminum, copper, gold, TiAlV, etc.

[0025] The second base end 21 is provided on the third angle C3 and fourth angle C4 sides with respect to the central axis AX in the second direction D2. The second base end 21 extends in the first direction D1 while bending once in the second direction D2 midway so as to avoid the fourth angle C4. Among the portions of the second base end 21 that extend in the first direction D1 and the portions of the first base end 11 that extend in the first direction D1, they face each other in the second direction D2.

[0026] The size of the second base end 21 may be any size as long as it is within an appropriate range in terms of both microfabrication feasibility and effectively reducing resistance. For example, the width of the second base end 21 is 1% - 40% of the element size of the bolometer 9, preferably 3 - 20%.

[0027] The plurality of second extension portions 22 protrude from the second base end 21 in the second direction D2 between the plurality of first extension portions 12. For example, the plurality of second extension portions 22 may be arranged in parallel at equal intervals in the second direction D2.

[0028] The size of each second extension portion 22 may be any size as long as it is within an appropriate range in terms of both microfabrication feasibility and effectively reducing resistance. Also, the number of the plurality of second extension portions 22 may be any number as long as it is within an appropriate range in terms of both microfabrication feasibility and effectively reducing resistance. For example, the width of each second extension portion 22 is 0.2 μm - 20 μm, preferably 0.2 μm - 1 μm. For example, the length of each second extension portion 22 is 20% - 99% of the element size of the bolometer 9, preferably 30 - 70%. For example, the number of the plurality of second extending portions 22 is 2 to 30, preferably 5 to 15.

[0029] Each of the plurality of second extending portions 22 extends linearly toward the first base end 11 up to immediately before the first base end 11. On the other hand, each of the plurality of first extending portions 12 extends linearly toward the second base end 21 up to immediately before the second base end 21.

[0030] Each of the plurality of second extending portions 22 extends so as to cross a pair of first extending portions 12 that extend toward each other while sandwiching both sides among the plurality of first extending portions 12. With such a configuration, the first electrode 1 and the second electrode 2 have a structure in which the plurality of first extending portions 12 and the plurality of second extending portions 22 are engaged with each other as a whole. In addition, an inter-electrode region AA is defined in the gap of such an engaged structure. For example, the width of the inter-electrode region AA may be 500 nm or more and 3 μm or less. In the present disclosure, the "width of the inter-electrode region AA" refers to the length of the inter-electrode region AA in the electrode facing direction between the first electrode 1 and the second electrode 2.

[0031] (Configuration of the sensor unit) The sensor unit 3 is a sensor for receiving infrared rays and detecting a quantity related to the intensity of the received infrared rays as a change amount of an electric resistance value. The sensor unit 3 has a function of converting the received infrared rays into heat and changing the electric resistance value between the first electrode 1 and the second electrode 2 in relation to the converted heat. The sensor unit 3 includes a carbon nanotube film 31, a light receiving unit 32, and a connection unit 33.

[0032] (Configuration of the carbon nanotube film) The carbon nanotube film 31 functions as an electric resistor whose electric resistance value changes in relation to heat. The carbon nanotube film 31 is electrically connected to the first electrode 1 and the second electrode 2 in the inter-electrode region AA. The carbon nanotube film 31 is electrically connected to the first electrode 1 and the second electrode 2 across the entire inter-electrode region AA along the inter-electrode region AA. For example, the carbon nanotube film 31 may extend in a meandering shape across the entire inter-electrode region AA by being filled across the entire inter-electrode region AA.

[0033] Specifically, by extending in a meandering shape, the carbon nanotube film 31 is electrically connected to a plurality of first extending portions 12 and a plurality of second extending portions 22 at least in a plurality of gap regions AB among the inter-electrode regions AA. Here, the plurality of gap regions AB are regions formed between the plurality of first extending portions 12 and the plurality of second extending portions 22 in the meandering inter-electrode region AA and extending in the second direction D2. In addition, the carbon nanotube film 31 is also electrically connected to the tips of the plurality of first extending portions 12 and the second base ends 21, and to the tips of the plurality of second extending portions 22 and the first base ends 11, even in portions connecting the plurality of gap regions AB in the first direction D1.

[0034] As shown in FIG. 4, the carbon nanotube film 31 has a first film side surface 31A and a second film side surface 31B. The first film side surface 31A is in contact with the first electrode side surface 12A of each first extending portion 12 of the first electrode 1 that faces the first direction D1 while extending along the inter-electrode region AA. The second film side surface 31B is in contact with the second electrode side surface 22A of each second extending portion 22 of the second electrode 2 that faces the first direction D1 while extending along the inter-electrode region AA. For example, the carbon nanotube film 31 may be connected above the plurality of first extending portions 12 and the plurality of second extending portions 22 so as to cover the upper surfaces of the plurality of first extending portions 12 and the plurality of second extending portions 22. For example, the carbon nanotube film 31 may also be in contact with the side surfaces of the first base end 11 and the second base end 21 that face each other and face the second direction D2.

[0035] For example, the thickness of the carbon nanotube film 31 may preferably be 0.7 nm or more and 50 nm or less, more preferably 0.7 nm or more and 10 nm or less, and even more preferably 0.7 nm or more and 5 nm or less.

[0036] For example, the carbon nanotube film 31 may contain single-walled carbon nanotubes. For example, the carbon nanotube film 31 may contain semiconducting carbon nanotubes. For example, the carbon nanotube film 31 may preferably contain 80% or more, and more preferably 90% or more, of semiconducting carbon nanotubes.

[0037] For example, the carbon nanotube film 31 may contain semiconducting carbon nanotubes extracted by the electric field-induced layer formation method (ELF method). The carbon nanotube film 31 may contain semiconducting carbon nanotubes extracted by other methods, but preferably contains semiconducting carbon nanotubes extracted by the ELF method. In that case, for example, from the viewpoint of being less likely to adversely affect the electrical characteristics of the bolometer 9, a nonionic surfactant may be used in the ELF method for extracting semiconducting carbon nanotubes.

[0038] For example, the length of a single semiconducting carbon nanotube separated by the ELF method may be 10 nm to 1 μm.

[0039] For example, in the carbon nanotube film 31, the semiconducting carbon nanotubes may be bundled. In that case, the length of the bundled state may be about 100 nm to 10 μm.

[0040] For example, the carbon nanotube film 31 may contain a carbon nanotube network film in which a plurality of carbon nanotubes are randomly oriented and form a network with each other. In the present disclosure, the "carbon nanotube network film" refers to a carbon nanotube film in which a plurality of carbon nanotubes are randomly oriented and form a network with each other.

[0041] (Configuration of the light-receiving part) As shown in FIGS. 1 and 2, the light-receiving part 32 is a thin film that spreads in a roof shape within the XY plane above and away from the protective film 5 at the upper part of the bolometer 9. The light-receiving part 32 covers one surface side of the region including the carbon nanotube film 31, the first electrode 1, and the second electrode 2. For example, the light-receiving part 32 may cover the upper surface side of the region including the carbon nanotube film 31, the first electrode 1, and the second electrode 2. Further, the region covered by the light-receiving part 32 may further include the wiring part 4.

[0042] For example, the light-receiving part 32 may have a plate shape with the XY plane as the plate surface, excluding the part where the connection part 33 is located. For example, the position of the light-receiving part 32 in the Z direction may be a position adjusted according to the wavelength and reflection position of the infrared rays transmitted through the light-receiving part 32 and reflected from the substrate 8 side. For example, the outer peripheral shape of the light-receiving part 32 may be rectangular, or even further square. For example, the light-receiving part 32 may have a through hole 32h on the central axis AX.

[0043] The light-receiving part 32 is formed of a material having a function of converting received infrared rays into heat, such as silicon nitride or titanium nitride.

[0044] (Configuration of the connection part) The connection part 33 extends in the stacking direction DS from the light-receiving part 32 to the carbon nanotube film 31. The connection part 33 supports the light-receiving part 32 on the carbon nanotube film 31, the first electrode 1, and the second electrode 2. The upper end of the connection part 33 is thermally connected to the light-receiving part 32. The lower end of the connection part 33 is thermally connected to the carbon nanotube film 31 through the protective film 5 by contacting the upper surface of the protective film 5. Further, the connection part 33 may be further thermally connected to the first electrode 1 and the second electrode 2 through the protective film 5. Specifically, the lower end of the connection part 33 may contact a portion provided over the upper surfaces of the carbon nanotube film 31, the first electrode 1, and the second electrode 2 among the upper surface of the protective film 5.

[0045] For example, the connection part 33 may have an upper surface that is recessed downward from the light receiving part 32 and a lower surface that protrudes downward in relation to this upper surface, and thus may extend in a recessed manner toward the carbon nanotube film 31. For example, when viewed from the Z direction, the connection part 33 may be recessed in an octagonal ring shape having a major axis in the direction connecting the first angle C1 and the third angle C3.

[0046] For example, the connection part 33 may be integrally formed of the same material as the light receiving part 32.

[0047] (Configuration of the wiring part) As shown in FIGS. 2 and 3, the wiring part 4 includes a first contact part 41, a first wiring 42, a second contact part 43, and a second wiring 44. The wiring part 4 supports the first electrode 1, the second electrode 2, and the sensor part 3 in the air so as to be separated from the substrate 8.

[0048] For example, the first contact part 41, the first wiring 42, and the first electrode 1 may be an integral thin film with each other. Similarly, the second contact part 43, the second wiring 44, and the second electrode 2 may be an integral thin film.

[0049] The first contact part 41 is provided on the first electrode 1 on the second electrode 2 side. Specifically, it is provided at a position closer to the fourth angle C4 than the central axis AX, and closer to the fourth angle C4 than the first angle C1, the second angle C2, and the third angle C3.

[0050] The first wiring 42 extends so as to connect the first base end 11 and the first contact portion 41. Specifically, the first wiring 42 extends from the first base end 11 to the first contact portion 41 along two sides among the four sides of the outer periphery of the bolometer 9 that sandwich the third corner C3, passing near the third corner C3.

[0051] The second contact portion 43 is provided on the first electrode 1 side with respect to the second electrode 2. Specifically, it is provided at a position closer to the second corner C2 than the center axis AX, and closer to the second corner C2 than the first corner C1, the third corner C3, and the fourth corner C4.

[0052] The second wiring 44 extends so as to connect the second base end 21 and the second contact portion 43. Specifically, the second wiring 44 extends from the second base end 21 to the second contact portion 43 along two sides among the four sides of the outer periphery of the bolometer 9 that sandwich the first corner C1, passing near the first corner C1.

[0053] The wiring portion 4 is formed of a conductive material such as aluminum, copper, gold, TiAlV, etc.

[0054] (Configuration of the protective film) The protective film 5 integrally covers the first electrode 1, the second electrode 2, the carbon nanotube film 31, and the wiring portion 4. The protective film 5 is an insulator such as silicon nitride, silicon oxide, resin, etc.

[0055] (Operation of the bolometer) The operation of the bolometer 9 of this embodiment will be described. When infrared rays are incident on and absorbed by the bolometer 9, heat is generated. For example, when the light receiving portion 32 absorbs infrared rays, heat is generated in the light receiving portion 32. The generated heat is transmitted through the connection portion 33 and warms the carbon nanotube film 31 via the protective film 5. When the carbon nanotube film 31 is warmed, the electrical resistance value of the carbon nanotube film 31 changes. The bolometer 9 detects the change in the electrical resistance value of the carbon nanotube film 31 in the electrode region AA by passing a current between the first electrode 1 and the second electrode 2, and detects infrared rays.

[0056] (Function and Effect) According to the bolometer 9 of the present embodiment, the electrode region AA where the carbon nanotube film 31 is electrically connected is meandering. Thereby, an electrical resistor of carbon nanotubes can be formed between the first electrode 1 and the second electrode 2, having a small length in the electrode facing direction and a large length in a direction intersecting the electrode facing direction. Therefore, the electrical resistance between the first electrode 1 and the second electrode 2 can be reduced.

[0057] As a comparative example, a bolometer using a vanadium oxide film as an electrical resistor is cited. The TCR of such a comparative example bolometer is small, about 2% / K. Also, in the comparative example bolometer, three strip-shaped electrical resistors are connected in series between the wiring portions for adjusting the electrical resistance value. On the other hand, the TCR of a bolometer using a carbon nanotube network film as an electrical resistor can achieve, for example, about 5% / K to 10% / K. For this reason, if an electrical resistor of a carbon nanotube net film is used instead of the electrical resistor of the vanadium oxide film in the bolometer of the comparative example, there is a possibility of making a bolometer with higher detectability. However, the carbon nanotube net film is several orders of magnitude larger than the sheet resistance of the vanadium oxide film. For this reason, when the structure of connecting strip-shaped electrical resistors in series is applied to a bolometer using a carbon nanotube network film as an electrical resistor, the electrical resistance becomes extremely large.

[0058] In contrast to such a comparative example, in the bolometer 9 of the present embodiment, since the electrode region AA where the carbon nanotube film 31 is electrically connected is meandering, the electrical resistance between the first electrode 1 and the second electrode 2 can be reduced as described above. Therefore, it is possible to achieve both an improvement in TCR and a reduction in electrical resistance.

[0059] Further, according to the present embodiment, the carbon nanotube film 31 is electrically connected to the plurality of first extending portions 12 and the plurality of second extending portions 22 at least in the plurality of gap regions AB. Thereby, the carbon nanotube film 31 is electrically connected to the plurality of first extending portions 12 and the plurality of second extending portions 22 over many regions in the inter-electrode region AA. Therefore, the electrical resistance between the first electrode 1 and the second electrode 2 can be reduced.

[0060] Further, according to the present embodiment, the light receiving portion 32 covers one surface side of the region including the carbon nanotube film 31, the first electrode 1, and the second electrode 2. When the inter-electrode region AA is meandering, the occupied areas of the first electrode 1 and the second electrode 2 tend to increase, and the occupied area of the carbon nanotube film 31 tends to decrease. On the other hand, in the present embodiment, since such a light receiving portion 32 is provided, the light receiving area of the bolometer 9 can be ensured regardless of the reduction of the occupied area of the carbon nanotube film 31. Therefore, a decrease in the fill factor of the bolometer 9 can be suppressed.

[0061] In particular, in a material having a large electrical resistance value such as the carbon nanotube film 31, it is necessary to increase the number of meandering undulations in the inter-electrode region AA as much as possible to increase the length in the direction intersecting the inter-electrode direction. For this reason, the occupied areas of the first electrode 1 and the second electrode 2 become larger, and the occupied area of the carbon nanotube film 31 becomes smaller. Therefore, in the bolometer 9 using the carbon nanotube film 31 as in the present embodiment, the light receiving portion 32 that brings about the effect of ensuring the light receiving area is useful.

[0062] Further, according to the present embodiment, since the first electrode side surface 12A of the carbon nanotube film 31 is in contact with the first electrode 1 and the second electrode side surface 22A is in contact with the second electrode 2, the carbon nanotube film 31 is electrically connected to the first electrode 1 and the second electrode 2 over the first electrode side surface 12A and the second electrode side surface 22A. Therefore, the electrical resistance between the first electrode 1 and the second electrode 2 can be reduced.

[0063] Also, according to the present embodiment, the carbon nanotube film 31 extends in a meandering shape in the inter-electrode region AA. Thereby, an electrical resistor of carbon nanotubes can be formed between the first electrode 1 and the second electrode 2, which has a small length in the inter-electrode direction and a large length in a direction intersecting the inter-electrode direction. Therefore, the electrical resistance between the first electrode 1 and the second electrode 2 can be reduced.

[0064] Also, according to the present embodiment, the carbon nanotube film 31 includes a carbon nanotube network film. Thereby, the TCR (Temperature Coefficient of Resistance) of the bolometer 9 can be increased. Therefore, the sensitivity of the bolometer 9 to infrared rays can be increased.

[0065] Also, according to the present embodiment, the width of the inter-electrode region AA is 500 nm or more and 3 μm or less. If the width of the inter-electrode region AA is within such a range, a high TCR and a low electrical resistance value can be achieved simultaneously in the carbon nanotube film 31 including the carbon nanotube network film. Specifically, it will be described below.

[0066] Generally, in a bolometer, when the inter-electrode distance is shortened, the electrical resistance value decreases, and when the inter-electrode distance is lengthened, the TCR tends to increase. On the other hand, in a bolometer in which electrodes are electrically connected by a carbon nanotube film, if the distance between the electrodes is extremely shortened, the current flowing through the metallic carbon nanotubes contained slightly becomes dominant, and the TCR tends to deteriorate extremely. For example, the length of carbon nanotubes obtained by the ELF method is about 300 nm or less. Since electrons can move relatively freely between one end and the other end of a single metallic carbon nanotube, if there are many metallic carbon nanotubes in a state where these both ends are in contact with the first electrode and the second electrode, it is considered that the current flowing through them becomes dominant in the film. Therefore, if the width of the region AA between the electrodes is 500 nm or more, almost no metallic carbon nanotubes whose both ends reach both the first electrode and the second electrode will exist, so that the bolometer 9 can maintain a large TCR.

[0067] On the other hand, when a carbon nanotube network film is formed using carbon nanotubes obtained by the ELF method and a silane coupling agent such as 3-aminopropyltriethoxysilane (APTES), it is known that the carbon nanotubes are locally oriented. At that time, the size of the domain, which is a region where the orientation directions of the carbon nanotubes are somewhat aligned, is about 3 μm at maximum. Therefore, if the width of the region AA between the electrodes is smaller than the size of this domain, a decrease in the electrical resistance value between the electrodes can be expected. Actually, the orientation directions of the carbon nanotubes in the domain are somewhat random, but by increasing the length in which the region AA between the electrodes extends, carbon nanotubes having an orientation advantageous for reducing the electrical resistance will exist within the region AA between the electrodes. Therefore, if the width of the region AA between the electrodes is 3 μm or less, the electrical resistance between the first electrode 1 and the second electrode 2 can be reduced.

[0068] Further, according to the present embodiment, the wiring portion 4 includes a first contact portion 41 provided on the second electrode 2 side, and a first wiring 42 connecting the first electrode 1 and the first contact portion 41. Further, the wiring portion 4 includes a second contact portion 43 provided on the first electrode 1 side, and a second wiring 44 connecting the second electrode 2 and the second contact portion 43. Thereby, while the first wiring 42 and the second wiring 44 are configured compactly, the first wiring 42 and the second wiring 44 can be configured to be long. Therefore, dissipation of the converted heat can be suppressed. Accordingly, a decrease in infrared sensitivity can be suppressed.

[0069] Further, according to the present embodiment, since the wiring portion 4 supports the first electrode 1, the second electrode 2, and the carbon nanotube film 31, dissipation of the converted heat can be suppressed. Accordingly, a decrease in infrared sensitivity can be suppressed.

[0070] Further, according to an example of the present embodiment, the light receiving portion 32 is separated from the substrate 8 over a wide range of the plate-shaped portion excluding the portion where the connecting portion 33 is located. With such a structure, the light receiving portion 32 can absorb a part of the infrared rays irradiated from above in a wide range of the plate-shaped portion, and can re-absorb, in a wide range of the plate-shaped portion, the infrared rays reflected from the substrate 8 side among the remaining transmitted infrared rays. Therefore, the light receiving portion 32 has a structure capable of absorbing a large amount of infrared rays.

[0071] Further, according to an example of the present embodiment, the connecting portion 33 is recessed in an octagonal annular shape having a major axis in the direction connecting the first angle C1 and the third angle C3 when viewed from the Z direction. With such a structure, the connecting portion 33 can support the light receiving portion 32 well-balancedly, and can widely transmit heat to the meandering electrode region AA.

[0072] (Modification) In the present embodiment, the sensor portion 3 includes the light receiving portion 32 and the connecting portion 33, but may be configured in any manner as long as it can detect infrared rays. As a modification, when the reduction of the occupied area of the carbon nanotube film 31 is not a problem, the sensor unit 3 may be configured to detect infrared rays by the carbon nanotube film 31 and the protective film 5 converting infrared rays into heat without including the light receiving unit 32 and the connection unit 33.

[0073] In an example of the present embodiment, the carbon nanotube film 31 is electrically connected to the first electrode 1 and the second electrode 2 across the entire inter-electrode region AA along the inter-electrode region AA. However, the carbon nanotube film 31 may be configured in any manner as long as it is electrically connected to the first electrode 1 and the second electrode 2 in the inter-electrode region AA. As a modification, the carbon nanotube film 31 may be electrically connected to the first electrode 1 and the second electrode 2 across a partial region of the meandering inter-electrode region AA. As another modification, the carbon nanotube film 31 may be electrically connected to the first electrode 1 and the second electrode 2 only in a plurality of gap regions AB of the meandering inter-electrode region AA. On the other hand, the more the carbon nanotube film 31 is electrically connected to the first electrode 1 and the second electrode 2 in more portions of the meandering inter-electrode region AA, the lower the electrical resistance between the first electrode 1 and the second electrode 2 is reduced.

[0074] In an example of the present embodiment, the carbon nanotube film 31 is in contact with the first electrode side surface 12A and the second electrode side surface 22A. However, the carbon nanotube film 31 may be configured in any manner as long as it is electrically connected to the first electrode 1 and the second electrode 2 in the inter-electrode region AA. As a modification, the carbon nanotube film 31 may be electrically connected to the upper surfaces of the first electrode 1 and the second electrode 2 above the first electrode side surface 12A and the second electrode side surface without contacting the first electrode side surface 12A and the second electrode side surface. On the other hand, when in contact with the first electrode side surface 12A and the second electrode side surface 22A, the carbon nanotube film 31 is more likely to reduce the electrical resistance between the first electrode 1 and the second electrode 2.

[0075] In an example of this embodiment, the first electrode 1 and the second electrode 2 include nine first extension portions 12 and nine second extension portions 22. However, if the electrode gap region AA can be configured in a meander shape, the first electrode 1 and the second electrode 2 may be configured in any way. As a modification, each of the plurality of first extension portions 12 and the plurality of second extension portions 22 may be two or more and less than nine. As another modification, each of the plurality of first extension portions 12 and the plurality of second extension portions 22 may be ten or more.

[0076] In an example of this embodiment, the plurality of first extension portions 12 and the plurality of second extension portions 22 are arranged at equal intervals in the Y direction. However, if the electrode gap region AA can be configured in a meander shape, the plurality of first extension portions 12 and the plurality of second extension portions 22 may be configured in any way. As a modification, the plurality of first extension portions 12 may be arranged at different intervals in the Y direction. As another modification, the plurality of second extension portions 22 may be arranged at different intervals in the Y direction.

[0077] In an example of this embodiment, the plurality of first extension portions 12 are arranged parallel to each other in the Y direction. However, if the electrode gap region AA can be configured in a meander shape, they do not necessarily have to be parallel. Similarly, in an example of this embodiment, the plurality of second extension portions 22 are arranged parallel to each other in the Y direction. However, if the electrode gap region AA can be configured in a meander shape, the plurality of second extension portions 22 do not necessarily have to be parallel.

[0078] In an example of this embodiment, each of the plurality of second extension portions 22 extends linearly. However, if it protrudes in the second direction D2, it does not necessarily have to be linear and may be curved. Similarly, in an example of this embodiment, each of the plurality of second extension portions 22 extends linearly. However, if it protrudes in the second direction D2, it does not necessarily have to be linear and may bend in the middle.

[0079] In an example of this embodiment, the connection portion 33 is recessed in an octagonal annular shape as viewed from the Z direction from the light-receiving portion 32. However, the connection portion 33 may be configured in any way as long as it can support the light-receiving portion 32 on the carbon nanotube film 31, the first electrode 1, and the second electrode 2 and thermally connect the carbon nanotube film 31, the first electrode 1, and the second electrode 2 to the light-receiving portion 32. As a modification, the connection portion 33 may be recessed in an annular shape such as a polygon, an ellipse, or a perfect circle as viewed from the Z direction from the light-receiving portion 32. As another modification, the connection portion 33 may have a prismatic or cylindrical shape extending downward from the light-receiving portion 32.

[0080] <Second Embodiment> Hereinafter, an embodiment of a method for manufacturing a bolometer according to the present disclosure will be described. The bolometer manufactured by the manufacturing method of this embodiment is common to the bolometer 9 of the first embodiment in that it includes a first electrode, a second electrode, a sensor portion, a wiring portion, and a protective film, but is different from the bolometer 9 of the first embodiment in the specific structure except for the points shown below.

[0081] (Steps of the manufacturing method) In the manufacturing method of this embodiment, as shown in FIG. 5, each step from ST01 to ST14 is performed.

[0082] First, as shown in FIG. 6, the manufacturer prepares a substrate 71 (ST01). Subsequent to the implementation of ST01, the manufacturer forms cell pads 72 on the substrate 71 as shown in FIG. 7 (ST02). Subsequent to the implementation of ST02, the manufacturer forms a first sacrificial layer 73 on the substrate 71 as shown in FIG. 8 (ST03). Subsequent to the implementation of ST03, the manufacturer forms a first lower protective film 74 on the first sacrificial layer 73 as shown in FIG. 9 (ST04). For example, the first sacrificial layer 73 is formed of an organic polyimide. Subsequent to the implementation of ST04, the manufacturer forms a second lower protective film 75 on the first lower protective film 74 as shown in FIG. 10 (ST05). Following the implementation of ST05, the manufacturer forms a first cell contact 76 on the substrate 71 as shown in FIG. 11 (ST06). Following the implementation of ST06, the manufacturer forms a TAV (Ti-6Al-4V) alloy film 77 on the second lower protective film 75 as shown in FIG. 12 (ST07).

[0083] Following the implementation of ST07, the manufacturer removes the TAV alloy film 77 in the portion indicated by the arrow and patterns the TAV alloy film 77 as shown in FIG. 13 (ST08). The patterned TAV alloy film 77 includes a first electrode and a second electrode provided with a meander-shaped interelectrode region interposed between the first electrode.

[0084] Following the implementation of ST08, the manufacturer forms a carbon nanotube 78 as shown in FIG. 14 (ST09). The carbon nanotube 78 is formed at least in the meander-shaped interelectrode region provided between the patterned TAV alloy films 77.

[0085] Following the implementation of ST09, the manufacturer forms a first upper protective film 79 on the carbon nanotube 78 as shown in FIG. 15 (ST10).

[0086] Following the implementation of ST10, the manufacturer forms a second upper protective film 80 on the first upper protective film 79 as shown in FIG. 16 (ST11).

[0087] Following the implementation of ST11, the manufacturer forms a second sacrificial layer 81 on the second upper protective film 80 as shown in FIG. 17 (ST12). For example, the second sacrificial layer 81 is formed of an organic polyimide.

[0088] Following the implementation of ST12, the manufacturer forms a light-receiving layer 82 on the second sacrificial layer 81 as shown in FIG. 18 (ST13). For example, the light-receiving layer 82 is formed of silicon nitride. Furthermore, in ST13, the manufacturer provides a through groove 83 in the formed light-receiving layer 82 toward the second sacrificial layer 81. The through groove 83 is an opening provided in ST14 later so that, for example, oxygen plasma can easily penetrate into the second sacrificial layer 81.

[0089] Subsequent to the implementation of ST13, the manufacturer removes the first sacrificial layer 73 and the second sacrificial layer 81 (ST14) as shown in FIG. 19. For example, the first sacrificial layer 73 and the second sacrificial layer 81 may be selectively removed by oxygen plasma. By this removal, a structure is formed in which the wiring portion supports the first electrode, the second electrode, and the sensor portion so that the first electrode, the second electrode, and the sensor portion are separated from the substrate.

[0090] Among the bolometers manufactured in this way, the light-receiving layer 82 corresponds to the light-receiving portion and the connection portion of the bolometer. Also, the carbon nanotube 78 corresponds to the carbon nanotube film of the bolometer. Also, the patterned TAV alloy film 77 corresponds to the first electrode, the second electrode, the first wiring, and the second wiring of the bolometer. Also, the first cell contact 76 corresponds to the first contact portion and the second contact portion. Also, the first lower protective film 74, the second lower protective film 75, the first upper protective film 79, and the second upper protective film 80 correspond to the protective film of the bolometer.

[0091] (Operation and Effect) According to the bolometer manufactured by the manufacturing method of the present embodiment, the region AA between the electrodes to which the carbon nanotube film is electrically connected has a meandering shape. Thereby, an electrical resistor of carbon nanotubes can be formed between the first electrode and the second electrode, having a small length in the electrode facing direction and a large length in a direction intersecting the electrode facing direction. Therefore, the electrical resistance between the first electrode and the second electrode can be reduced.

[0092] (Modification) The method for manufacturing a bolometer is not limited to the above-described manufacturing method, and any manufacturing method may be used as long as it can manufacture a bolometer including a first electrode, a second electrode, a sensor unit, a wiring unit, and a protective film. As a modification, each step as shown in FIGS. 20 to 25 may be performed in the method for manufacturing a bolometer. In this modification, first, as shown in FIG. 20, the manufacturer forms a lower protective film 174, which is an insulating film, on a substrate 171 (ST101: lower protective film forming step). Subsequent to the implementation of ST102, the manufacturer forms an electrode film 177 and a carbon nanotube network film 178 on the lower protective film 174 as shown in FIG. 21 (ST102: CNT network forming step). The electrode film 177 includes a first electrode and a second electrode provided with a meandering inter-electrode region interposed therebetween with respect to the first electrode. The carbon nanotube network film 178 is formed in the meandering inter-electrode region provided in the electrode film 177. Subsequent to the implementation of ST102, the manufacturer forms an upper protective film 175, which is an insulating film, on the electrode film 177 and the carbon nanotube network film 178 as shown in FIG. 22 (ST103: upper protective film forming step). Here, the entire electrode film 177 and the carbon nanotube network film 178 are covered with the lower protective film 174 and the upper protective film 175. Subsequent to the implementation of ST103, the manufacturer forms exposed portions of the electrode film 177 and the carbon nanotube network film 178 at the end face by etching as shown in FIG. 23 (ST104: exposed portion forming step). Subsequent to the implementation of ST104, the manufacturer forms a contact electrode 176 as shown in FIG. 25 (ST105: contact electrode forming step). By implementing ST104, the electrode film 177, the carbon nanotube network film 178, and the contact electrode 176 are electrically connected at the exposed portions of the end face.

[0093] <Third Embodiment> Hereinafter, an embodiment of a bolometer according to the present disclosure will be described.

[0094] (Configuration) The bolometer 109 includes a first electrode 101, a second electrode 102, and a sensor unit 103. The second electrode 102 is provided with respect to the first electrode 101 with a meandering inter-electrode region AA interposed therebetween. The sensor unit 103 includes a carbon nanotube film 131 that is electrically connected to the first electrode 101 and the second electrode 102 in the inter-electrode region AA.

[0095] (Function and Effect) According to the bolometer 109 of the present embodiment, the inter-electrode region AA in which the carbon nanotube film 131 is electrically connected is meandering. Thereby, an electrical resistor of carbon nanotubes can be formed between the first electrode 101 and the second electrode 102, having a small length in the electrode facing direction and a large length in a direction intersecting the electrode facing direction. Therefore, the electrical resistance between the first electrode 101 and the second electrode 102 can be reduced.

[0096] As described above, the embodiments of the present disclosure have been described. However, this embodiment is shown as an example and is not intended to limit the scope of the present disclosure. This embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the present disclosure. And each embodiment can be combined with other embodiments as appropriate.

[0097] Some or all of the above embodiments can be described as follows in the appended claims, but are not limited thereto.

[0098] (Appended Claim 1) A first electrode, A second electrode provided with respect to the first electrode with a meandering inter-electrode region interposed therebetween, A sensor unit including a carbon nanotube film that is electrically connected to the first electrode and the second electrode in the inter-electrode region, Comprising, Bolometer.

[0099] (Appendix 2) The first electrode has a first base end extending in a first direction and a plurality of first extending portions protruding from the first base end in a second direction intersecting the first direction. The second electrode has a second base end extending in the first direction and a plurality of second extending portions protruding from the second base end in the second direction between the plurality of first extending portions. The carbon nanotube film is electrically connected to the plurality of first extending portions and the plurality of second extending portions in a plurality of gap regions formed at least between the plurality of first extending portions and the plurality of second extending portions in the electrode region. The bolometer according to Appendix 1.

[0100] (Appendix 3) The sensor unit a light receiving portion covering one surface side of the region including the carbon nanotube film, the first electrode, and the second electrode; a connecting portion extending from the light receiving portion to the carbon nanotube film; further includes The bolometer according to Appendix 1 or 2.

[0101] (Appendix 4) The carbon nanotube film has a first film side surface extending along the electrode region and in contact with the first electrode, and a second film side surface extending along the electrode region and in contact with the second electrode. The bolometer according to any one of Appendices 1 to 3.

[0102] (Appendix 5) The carbon nanotube film extends in a meandering shape in the electrode region. The bolometer according to any one of Appendices 1 to 4.

[0103] (Appendix 6) The carbon nanotube film includes a carbon nanotube network film. The bolometer according to Supplementary Notes 1 to 5.

[0104] (Supplementary Note 7) The width of the region between the electrodes is 500 nm or more and 3 μm or less. The bolometer according to Supplementary Note 6.

[0105] (Supplementary Note 8) Further comprising a wiring portion. The wiring portion includes a first contact portion provided on the second electrode side, a first wiring connecting the first electrode and the first contact portion, a second contact portion provided on the first electrode side, and a second wiring connecting the second electrode and the second contact portion. The bolometer according to any one of Supplementary Notes 1 to 7.

[0106] (Supplementary Note 9) The wiring portion supports the first electrode, the second electrode, and the carbon nanotube film. The bolometer according to Supplementary Note 8.

[0107] (Supplementary Note 10) Comprising a plurality of bolometers according to any one of Supplementary Notes 1 to 9. Further comprising a substrate on which the plurality of bolometers are arranged side by side. Bolometer array.

Explanation of Reference Numerals

[0108] 1 First electrode 2 Second electrode 3 Sensor portion 4 Wiring portion 5 Protective film 8 Substrate 9 Bolometer 11 First base end 12 First extension portion 12A First electrode side surface 21 Second base end 22 Second extension portion 22A Second electrode side surface 31 Carbon nanotube film 31A First film side surface 31B Second film side surface 32 Light-receiving part 32h Through-hole 33 Connection part 41 First contact part 42 First wiring 43 Second contact part 44 Second wiring 71 Substrate 72 Cell pad 73 First sacrificial layer 74 First lower protective film 75 Second lower protective film 76 First cell contact 77 TAV alloy film 78 Carbon nanotube 79 First upper protective film 80 Second upper protective film 81 Second sacrificial layer 82 Light-receiving layer 83 Through-groove 99 Bolometer array 101 First electrode 102 Second electrode 103 Sensor part 109 Bolometer 131 Carbon nanotube film 171 Substrate 174 Lower protective film 175 Upper protective film 176 Contact electrode 177 Electrode film 178 Carbon nanotube network film AA Region between electrodes AB Gap region AX Central axis C1 First angle C2 Second angle C3 Third angle C4 Fourth angle D1 First direction D2 Second direction DS Lamination direction

Claims

1. A first electrode, a second electrode provided with respect to the first electrode with a meandering electrode gap region therebetween, and a sensor unit including a carbon nanotube film electrically connected to the first electrode and the second electrode in the electrode gap region. The sensor unit comprises: a bolometer.

2. The first electrode has a first proximal end extending in a first direction and a plurality of first extensions protruding from the first proximal end in a second direction intersecting the first direction. The second electrode has a second proximal end extending in the first direction and a plurality of second extensions protruding from the second proximal end in the second direction between the plurality of first extensions. The carbon nanotube film is electrically connected to the plurality of first extensions and the plurality of second extensions in a plurality of gap regions formed at least between the plurality of first extensions and the plurality of second extensions in the electrode gap region. The bolometer according to claim 1.

3. The sensor unit further comprises: a light receiving portion covering one surface side of a region including the carbon nanotube film, the first electrode, and the second electrode; and a connection portion extending from the light receiving portion to the carbon nanotube film. The bolometer according to claim 1 or 2.

4. The carbon nanotube film has a first film side surface extending along the electrode gap region and in contact with the first electrode, and a second film side surface extending along the electrode gap region and in contact with the second electrode. The bolometer according to claim 1 or 2.

5. The carbon nanotube film extends in a meandering shape in the electrode gap region. The bolometer according to claim 1 or 2.

6. The carbon nanotube film includes a carbon nanotube network film. The bolometer according to claim 1 or 2.

7. The width of the electrode gap region is 500 nm or more and 3 μm or less. The bolometer according to claim 6.

8. The bolometer further comprises a wiring portion, wherein the wiring portion includes a first contact portion provided on the second electrode side, a first wiring connecting the first electrode and the first contact portion, a second contact portion provided on the first electrode side, and a second wiring connecting the second electrode and the second contact portion. The bolometer according to claim 1 or 2.

9. The wiring portion supports the first electrode, the second electrode, and the carbon nanotube film. The bolometer according to claim 8. ​

10. comprising a plurality of bolometers according to claim 1 or 2, further comprising a substrate on which the plurality of bolometers are arranged side by side, a bolometer array.

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