Electromagnetic wave detection device, electromagnetic wave detection system, and electromagnetic wave detection method

Abstract

The present invention discloses an electromagnetic wave detection device, comprising: an electromagnetic wave absorbing layer containing a low-dimensional electronic material that absorbs electromagnetic waves; a first electrode disposed on a first main surface of the electromagnetic wave absorbing layer; a second electrode disposed on a second main surface of the electromagnetic wave absorbing layer opposite to the first main surface; and a readout circuit that reads from the second electrode a signal generated by thermoelectric conversion through heat generated by the electromagnetic wave absorbing layer that has absorbed electromagnetic waves.

Description

Technical Field

[0001] This disclosure relates to an electromagnetic wave detection device, an electromagnetic wave detection system, and an electromagnetic wave detection method. Background Technology

[0002] In recent years, sensors have been developed that acquire information from objects by detecting light or electromagnetic waves that cannot be perceived by humans.

[0003] For example, sensors have been developed that use carbon nanotubes to detect terahertz waves in the 0.1 THz to 50 THz frequency band (e.g., Patent Document 1). Terahertz waves are electromagnetic waves that correspond to the intermediate region between light and radio waves and can be used to construct optical measurement systems. Therefore, terahertz waves have attracted much attention in recent years.

[0004] List of cited references

[0005] Patent documents

[0006] Patent Document 1: International Publication No. 2017 / 188438 Summary of the Invention

[0007] However, compared to sensors that detect visible light, it's difficult to say that the sensor structure has been fully studied for sensors that detect light or electromagnetic waves that are imperceptible to humans. Therefore, further research into sensor structure is expected to improve sensor performance or reduce costs.

[0008] Therefore, it is desirable to provide an electromagnetic wave detection device and an electromagnetic wave detection system with a structure suitable for further improving performance or reducing costs, as well as an electromagnetic wave detection method using the electromagnetic wave detection device and electromagnetic wave detection system.

[0009] An electromagnetic wave detection device according to one embodiment of the present disclosure includes: an electromagnetic wave absorbing layer comprising a low-dimensional electronic material that absorbs electromagnetic waves; a first electrode disposed on a first main surface of the electromagnetic wave absorbing layer; a second electrode disposed on a second main surface of the electromagnetic wave absorbing layer opposite to the first main surface; and a readout circuit that reads from the second electrode a signal generated by thermoelectric conversion of heat generated by the electromagnetic wave absorbing layer that has absorbed electromagnetic waves.

[0010] Additionally, an electromagnetic wave detection system according to one embodiment of this disclosure includes: an electromagnetic wave detection device; and a shutter that controls the incidence of electromagnetic waves on the electromagnetic wave detection device. The electromagnetic wave detection device includes: an electromagnetic wave absorbing layer comprising a low-dimensional electronic material that absorbs electromagnetic waves; a first electrode disposed on a first main surface of the electromagnetic wave absorbing layer; a second electrode disposed on a second main surface of the electromagnetic wave absorbing layer opposite to the first main surface; and a readout circuit that reads from the second electrode a signal generated by thermoelectric conversion through heat generated by the electromagnetic wave absorbing layer absorbing electromagnetic waves.

[0011] Additionally, an electromagnetic wave detection method according to one embodiment of this disclosure includes: absorbing electromagnetic waves by means of a low-dimensional electronic material contained in an electromagnetic wave absorbing layer sandwiched between a first electrode and a second electrode on opposite main surfaces; performing thermoelectric conversion on the heat generated by the electromagnetic wave absorbing layer by absorbing the electromagnetic waves; and reading out the signal generated by the thermoelectric conversion from the second electrode.

[0012] In an electromagnetic wave detection apparatus, electromagnetic wave detection system, and electromagnetic wave detection method according to one embodiment of the present disclosure, a thermoelectric conversion-based signal can be read from the second electrode using the temperature difference between a first electrode disposed on a first main surface of an electromagnetic wave absorbing layer containing low-dimensional electronic material that absorbs electromagnetic waves and a second electrode disposed on a second main surface of the electromagnetic wave absorbing layer opposite to the first main surface. For example, this can read from the second electrode a signal corresponding to the energy of the electromagnetic waves absorbed by the electromagnetic wave absorbing layer. Attached Figure Description

[0013] Figure 1 This is a schematic diagram showing the cross-section and top surface configuration of an electromagnetic wave detection device according to a first embodiment of the present disclosure.

[0014] Figure 2A This is an illustrative diagram showing the Seebeck effect in an n-type semiconductor.

[0015] Figure 2B This is an illustrative diagram showing the Seebeck effect in a p-type semiconductor.

[0016] Figure 3 This is a flowchart illustrating the electromagnetic wave detection method used in the electromagnetic wave detection device according to the embodiment.

[0017] Figure 4A This is a three-dimensional diagram of the configuration of the electromagnetic wave detection device based on the first comparative example.

[0018] Figure 4B It is shown Figure 4A A schematic diagram of the energy of the electromagnetic wave absorption layer in the electromagnetic wave detection device shown.

[0019] Figure 5A This is a three-dimensional diagram of the electromagnetic wave detection device based on the second comparative example.

[0020] Figure 5B It is shown Figure 5A A schematic diagram of the energy of the electromagnetic wave absorption layer in the electromagnetic wave detection device shown.

[0021] Figure 6 This is a schematic diagram showing the cross-sectional configuration of an electromagnetic wave detection device according to a second embodiment of the present disclosure.

[0022] Figure 7A This is an energy diagram showing the relationship between the energy levels of the buffer layer and the electromagnetic wave absorbing layer when the electromagnetic wave absorbing layer is an n-type semiconductor layer.

[0023] Figure 7B This is an energy diagram showing the relationship between the energy levels of the buffer layer and the electromagnetic wave absorbing layer when the electromagnetic wave absorbing layer is a p-type semiconductor layer.

[0024] Figure 8 This is a schematic diagram showing the cross-section and top surface configuration of an electromagnetic wave detection device according to a third embodiment of this disclosure.

[0025] Figure 9 This is a schematic diagram showing the cross-sectional configuration of an electromagnetic wave detection device according to the fourth embodiment of this disclosure.

[0026] Figure 10A This is a longitudinal cross-sectional view of the steps in the method for forming the insulating part of the electromagnetic wave detection device according to the implementation plan.

[0027] Figure 10B This is a longitudinal cross-sectional view of the steps in the method for forming the insulating part of the electromagnetic wave detection device according to the implementation plan.

[0028] Figure 10C This is a longitudinal cross-sectional view of the steps in the method for forming the insulating part of the electromagnetic wave detection device according to the implementation plan.

[0029] Figure 10D This is a longitudinal cross-sectional view of the steps in the method for forming the insulating part of the electromagnetic wave detection device according to the implementation plan.

[0030] Figure 10E This is a longitudinal cross-sectional view of the steps in the method for forming the insulating part of the electromagnetic wave detection device according to the implementation plan.

[0031] Figure 11 This is a schematic diagram showing the cross-sectional configuration of an electromagnetic wave detection device according to a fifth embodiment of the present disclosure.

[0032] Figure 12AThis is a longitudinal cross-sectional view of the steps in the manufacturing method of the electromagnetic wave detection device according to the implementation plan.

[0033] Figure 12B This is a longitudinal cross-sectional view of the steps in the manufacturing method of the electromagnetic wave detection device according to the implementation plan.

[0034] Figure 12C This is a longitudinal cross-sectional view of the steps in the manufacturing method of the electromagnetic wave detection device according to the implementation plan.

[0035] Figure 12D This is a longitudinal cross-sectional view of the steps in the manufacturing method of the electromagnetic wave detection device according to the implementation plan.

[0036] Figure 12E This is a longitudinal cross-sectional view of the steps in the manufacturing method of the electromagnetic wave detection device according to the implementation plan.

[0037] Figure 12F This is a longitudinal cross-sectional view of the steps in the manufacturing method of the electromagnetic wave detection device according to the implementation plan.

[0038] Figure 13 This is a block diagram illustrating an example of the general structure of an electromagnetic wave detection system.

[0039] Figure 14 An example flowchart of the imaging operation in an electromagnetic wave detection system is shown.

[0040] Figure 15 This is a block diagram illustrating an example of the schematic configuration of a vehicle control system.

[0041] Figure 16 This diagram illustrates the installation locations of the vehicle exterior information detection unit and the imaging unit. Detailed Implementation

[0042] The following detailed description of embodiments of this disclosure is given with reference to the accompanying drawings. The embodiments described below are specific examples of this disclosure, and the technology based on this disclosure should not be limited to these embodiments. Furthermore, the arrangement, dimensions, and aspect ratios of the various components of this disclosure are not limited to those shown in the drawings.

[0043] Note that the explanations are given in the following order.

[0044] 1. First Implementation Plan

[0045] 1.1. Composition of Electromagnetic Wave Detection Device

[0046] 1.2. Electromagnetic wave detection methods

[0047] 1.3. Explanation of Effects

[0048] 2. Second Implementation Plan

[0049] 3. Third Implementation Plan

[0050] 4. Fourth Implementation Plan

[0051] 4.1. Composition of Electromagnetic Wave Detection Device

[0052] 4.2. Methods for forming the insulation section

[0053] 5. Fifth Implementation Plan

[0054] 5.1. Composition of Electromagnetic Wave Detection Device

[0055] 5.2. Manufacturing method of electromagnetic wave detection device

[0056] 6. Applicable Examples

[0057] <1. First Implementation Plan>

[0058] (1.1. Composition of Electromagnetic Wave Detection Device)

[0059] First, refer to Figure 1 The composition of the electromagnetic wave detection device according to the first embodiment of this disclosure is described. Figure 1 This is a schematic diagram showing the cross-section and top surface configuration of the electromagnetic wave detection device 100 according to this embodiment.

[0060] like Figure 1 As shown, for example, the electromagnetic wave detection device 100 includes an electromagnetic wave absorbing layer 130, a first electrode 110, a second electrode 120, and an insulating layer 140.

[0061] For example, the electromagnetic wave detection device 100 is a two-dimensional array type detection device in which a plurality of sensor pixels for detecting electromagnetic waves EM are arranged in a two-dimensional manner. In the following description, the area in which the sensor pixels for detecting electromagnetic waves EM are arranged in a two-dimensional manner is also referred to as the pixel area.

[0062] The electromagnetic wave absorbing layer 130 is a semiconductor layer comprising low-dimensional electronic materials. The electromagnetic wave absorbing layer 130 absorbs electromagnetic waves EM incident on the electromagnetic wave detection device 100 and converts the absorbed electromagnetic waves into heat. By converting the incident electromagnetic wave EM into heat, the electromagnetic wave absorbing layer 130 can generate an electromotive force corresponding to the electromagnetic wave EM through thermoelectric conversion.

[0063] Specifically, the electromagnetic wave absorbing layer 130 can form a temperature gradient in the thickness direction by absorbing the incident electromagnetic wave EM and converting it into heat. This enables the electromagnetic wave detection device 100 to extract the signal corresponding to the electromagnetic wave EM incident on each pixel from the second electrode 120 by converting the temperature difference caused in the thickness direction of the electromagnetic wave absorbing layer 130 into an electromotive force using the Seebeck effect.

[0064] Here, refer to Figure 2A and Figure 2B Explain the Seebeck effect. Figure 2A This is an illustrative diagram showing the Seebeck effect in an n-type semiconductor. Figure 2B This is an illustrative diagram showing the Seebeck effect in a p-type semiconductor.

[0065] The Seebeck effect is a thermoelectric effect in which the temperature difference in an object is directly converted into voltage.

[0066] For example, such as Figure 2A As shown, in the electromagnetic wave absorbing layer 130n, which is an n-type semiconductor, charge carriers (i.e., electrons) 91 are provided by a thermally excited ionized donor 92. Therefore, when a high-temperature region 131 and a low-temperature region 132 are generated in the electromagnetic wave absorbing layer 130n through absorption by electromagnetic waves such as EM, the concentration of charge carriers 91 in the high-temperature region 131 increases exponentially with respect to temperature. In this case, a concentration gradient of charge carriers 91 is formed between the high-temperature region 131 and the low-temperature region 132. Therefore, the charge carriers 91 in the high-temperature region 131 diffuse towards the low-temperature region 132 by the diffusion force generated by the concentration difference.

[0067] At this point, the ionized donor 92 is fixed as an ion in the crystal and therefore does not diffuse. Consequently, the high-temperature section 131 exhibits a positive charge opposite to that of the charge carrier 91. Therefore, a Coulomb force resulting from the charge imbalance between the high-temperature section 131 and the low-temperature section 132 generates a force that pushes the charge carrier 91 back to the high-temperature section 131. Thus, an electromotive force En matching the diffusion force caused by the concentration difference of the charge carrier 91 is generated between the high-temperature section 131 and the low-temperature section 132 of the electromagnetic wave absorbing layer 130n.

[0068] On the other hand, such as Figure 2B As shown, in the electromagnetic wave absorbing layer 130p, which is a p-type semiconductor, charge carriers 94 (i.e., holes) are provided by acceptors 93 that are ionized by thermal excitation. Therefore, when a high-temperature region 131 and a low-temperature region 132 are generated in the electromagnetic wave absorbing layer 130p by absorption of electromagnetic waves such as EM, the concentration of charge carriers 94 in the high-temperature region 131 increases exponentially with respect to temperature. In this case, a concentration gradient of charge carriers 94 is formed between the high-temperature region 131 and the low-temperature region 132. Therefore, the charge carriers 94 in the high-temperature region 131 diffuse to the low-temperature region 132 by the diffusion force generated by the concentration difference.

[0069] At this point, the ionized acceptor 93 is fixed as an ion in the crystal and therefore does not diffuse. Consequently, the high-temperature section 131 exhibits a negative charge opposite to that of the charge carrier 94. Therefore, a Coulomb force resulting from the charge imbalance between the high-temperature section 131 and the low-temperature section 132 generates a force that pushes the charge carrier 94 back into the high-temperature section 131. Thus, an electromotive force Ep is generated between the high-temperature section 131 and the low-temperature section 132 of the electromagnetic wave absorbing layer 130p, matching the diffusion force caused by the concentration difference of the charge carrier 91.

[0070] In the electromagnetic wave detection device 100 according to this embodiment, the electromagnetic wave EM absorbed by the electromagnetic wave absorption layer 130 and converted into heat results in a high-temperature region on the first main surface side of the electromagnetic wave absorption layer 130 and a low-temperature region on the second main surface side. Therefore, an electromotive force due to the Seebeck effect is generated between the first and second main surface sides of the electromagnetic wave absorption layer 130, which is a semiconductor layer. Thus, the electromagnetic wave detection device 100 can detect the amount of incident electromagnetic wave EM by detecting the potential difference between the first electrode 110 and the second electrode 120 or the amount of current flowing between the first electrode 110 and the second electrode 120.

[0071] The electromagnetic wave absorption layer 130 can be configured as a common layer covering the entire pixel area. In the electromagnetic wave detection apparatus 100 according to this embodiment, in order to obtain sufficient absorption of electromagnetic waves, the thickness of the electromagnetic wave absorption layer 130 is preferably several hundred nm or more. Furthermore, the thickness of the electromagnetic wave absorption layer 130 is more preferably 1 μm or more, so as to form a temperature gradient in the thickness direction of the electromagnetic wave absorption layer 130. Note that, considering the resolution limitation based on the wavelength of the electromagnetic wave EM to be detected, the size of a pixel in the electromagnetic wave absorption layer 130 is several μm to several hundred μm. In the electromagnetic wave detection apparatus 100 according to this embodiment, configuring the electromagnetic wave absorption layer 130 as a common layer covering the entire pixel area can further simplify the manufacturing process of the electromagnetic wave detection apparatus 100.

[0072] The low-dimensional electronic material contained in the electromagnetic wave absorbing layer 130 is a semiconductor material in which the movement of electrons within it is confined to a region of less than two dimensions. Specifically, the low-dimensional electronic material is a two-dimensional electronic material such as graphene, a one-dimensional electronic material such as carbon nanotubes, or a zero-dimensional electronic material such as fullerenes. For example, the electromagnetic wave absorbing layer 130 may contain carbon nanotubes or graphene as a low-dimensional electronic material.

[0073] When the electromagnetic wave absorbing layer 130 contains carbon nanotubes, it can absorb electromagnetic waves (EM) across a very wide frequency band, from the ultraviolet region to the terahertz wave region, and convert the absorbed EM into heat. For example, the electromagnetic wave absorbing layer 130 can enable the electromagnetic wave detection device 100 to function as a terahertz wave detection device by absorbing electromagnetic waves (EM) in a frequency band above 100 GHz and below 75 THz.

[0074] A first electrode 110 is disposed on the first main surface of the electromagnetic wave absorbing layer 130. Specifically, the first electrode 110 is configured as a common electrode covering the entire first main surface of the electromagnetic wave absorbing layer 130, and is configured with a plurality of openings 111 arranged in a two-dimensional pattern. That is, the first electrode 110 can be configured to cover the entire first main surface of the electromagnetic wave absorbing layer 130, serving as a grid-like common electrode defining each pixel. The plurality of openings 111 provided for the first electrode 110 serve as quadrilateral pixels.

[0075] The first electrode 110 may be made of a conductive material that does not absorb electromagnetic waves (EM) in the frequency band of the electromagnetic wave detection target of the electromagnetic wave detection device 100. Specifically, the first electrode 110 may include a conductive material comprising aluminum (Al), titanium (Ti), titanium nitride (TiN), tungsten (W), nickel (Ni), copper (Cu), bismuth (Bi), or indium (In). For example, the first electrode 110 may include a conductive material comprising Ti, Bi, or Ni.

[0076] The second electrode 120 is disposed on the second main surface of the electromagnetic wave absorbing layer 130 opposite to the first main surface. Specifically, the second electrode 120 is disposed in a region corresponding to a plurality of openings 111 provided for the first electrode 110, so as to be separated from each pixel. For example, the second electrode 120 may be configured as a quadrilateral to correspond to each opening 111 of the first electrode 110. In addition, a readout circuit (not shown) is electrically connected to the second electrode 120 and reads out the voltage or current corresponding to the incident electromagnetic wave EM from the second electrode 120 for each pixel.

[0077] The second electrode 120 may comprise a conductive material. Specifically, the second electrode 120 may comprise a conductive material comprising aluminum (Al), titanium (Ti), titanium nitride (TiN), tungsten (W), copper (Cu), or indium (In). For example, the second electrode 120 may comprise a conductive material comprising Ti.

[0078] The first electrode 110 and the second electrode 120 may comprise conductive materials having different thermal conductivities from each other. In this case, the first electrode 110 and the second electrode 120 can generate a larger temperature gradient in the thickness direction of the electromagnetic wave absorbing layer 130 due to thermal movement from the electromagnetic wave absorbing layer 130.

[0079] Furthermore, the first electrode 110 can suppress thermal crosstalk between adjacent pixels by incorporating a conductive material with high thermal conductivity, and more clearly separates the temperatures of adjacent pixels. However, in this case, the electromotive force between the first electrode 110 and the electromagnetic wave absorbing layer 130 has the opposite direction to the electromotive force between the second electrode 120 and the electromagnetic wave absorbing layer 130. Therefore, mutually canceling components may be generated in the electromotive force between the first electrode 110 and the second electrode 120. Therefore, it is important to appropriately select the conductive material incorporated in the first electrode 110 and the second electrode 120, taking into account the sensitivity of the electromagnetic wave EM to be detected and the crosstalk amplitude between pixels.

[0080] The insulating layer 140 protects the electromagnetic wave absorbing layer 130 by using an insulating material disposed on the electromagnetic wave absorbing layer 130 and the first electrode 110. Because the insulating layer 140 is disposed on the incident side of the electromagnetic wave EM relative to the electromagnetic wave absorbing layer 130, it is desirable that the insulating layer 140 contains an insulating material with a lower absorption rate for the electromagnetic wave EM in the target frequency band than that of the electromagnetic wave absorbing layer 130. Furthermore, to suppress the diffusion of heat generated by absorbing the electromagnetic wave EM to the outside of the electromagnetic wave absorbing layer 130, the insulating layer 140 is desirable to contain an insulating material with a lower thermal conductivity than that of the electromagnetic wave absorbing layer 130. For example, if the electromagnetic wave absorbing layer 130 contains carbon nanotubes, the insulating layer 140 may contain silicon oxide (SiO2). x ), silicon nitride (SiN) x Insulating materials such as aluminum oxide (Al2O3) or aluminum oxide.

[0081] With the above configuration, the electromagnetic wave detection device 100 according to this embodiment can generate a temperature gradient in the thickness direction of the electromagnetic wave absorption layer 130 by absorbing electromagnetic waves EM, and generate an electromotive force based on the temperature gradient. Therefore, the electromagnetic wave detection device 100 according to this embodiment can read out the signal corresponding to the electromagnetic wave EM incident on the pixel for each pixel disposed in the in-plane direction of the electromagnetic wave absorption layer 130.

[0082] The electromagnetic wave detection device 100 according to this embodiment can be manufactured using known semiconductor manufacturing methods. For example, the electromagnetic wave absorbing layer 130 can be formed using spin coating. The first electrode 110 and the second electrode 120 can be formed using sputtering. The insulating layer 140 can be formed using CVD (chemical vapor deposition).

[0083] (1.2. Electromagnetic wave detection methods)

[0084] Next, refer to Figure 3 This describes the electromagnetic wave detection method used by the electromagnetic wave detection device according to this embodiment. Figure 3 This is a flowchart illustrating the process of an electromagnetic wave detection method used by an electromagnetic wave detection device according to this embodiment.

[0085] like Figure 3 As shown, firstly, electromagnetic wave EM is incident on the electromagnetic wave absorption layer 130 of the electromagnetic wave detection device 100 (S10).

[0086] In the electromagnetic wave absorbing layer 130 where the electromagnetic wave EM is incident, the incident electromagnetic wave EM is absorbed by the low-dimensional electronic material, and the energy of the absorbed electromagnetic wave EM is converted into heat (S20).

[0087] Therefore, in the electromagnetic wave absorbing layer 130, a temperature gradient is generated in which the first electrode 110 on the electromagnetic wave EM incident surface side has a high temperature and the second electrode 120 opposite to the first electrode 110 has a low temperature (S30).

[0088] The temperature gradient generated in the electromagnetic wave absorbing layer 130 results in a temperature difference between the first electrode 110 and the second electrode 120. The temperature difference between the first electrode 110 and the second electrode 120 is converted into an electromotive force through the Seebeck effect (S40).

[0089] Subsequently, a signal based on the electromotive force caused by the Seebeck effect is read from the second electrode 120 (S50).

[0090] By operating according to the above process, the electromagnetic wave detection device 100 according to this embodiment can detect electromagnetic waves EM incident on the electromagnetic wave absorbing layer 130.

[0091] (1.3. Explanation of the effects)

[0092] Next, refer to Figures 4A to 5B The effect of the electromagnetic wave detection device 100 according to this embodiment will be specifically explained by comparing the electromagnetic wave detection device according to the first comparative example and the electromagnetic wave detection device according to the second comparative example.

[0093] Figure 4A This is a perspective view of the configuration of the electromagnetic wave detection device 10 based on the first comparative example. Figure 4B It is shown Figure 4A A schematic diagram of the energy of the electromagnetic wave absorbing layer 13 in the electromagnetic wave detection device 10 shown.

[0094] like Figure 4AAs shown, the electromagnetic wave detection device 10 according to the first comparative example is constructed by arranging a first electrode 11 and a second electrode 12, which are separated from each other, on one main surface of the electromagnetic wave absorbing layer 13. In the first comparative example, the electromagnetic wave absorbing layer 13 is configured as a p-type semiconductor layer, and the first electrode 11 and the second electrode 12 contain materials having different thermal conductivities from each other.

[0095] Here, as Figure 4B As shown, the heat generated by the electromagnetic wave absorbing layer 13, which absorbs electromagnetic waves (EM), diffuses to the first electrode 11 and the second electrode 12. Therefore, in the electromagnetic wave absorbing layer 13, the central portion becomes a high-temperature portion, and the ends where the first electrode 11 and the second electrode 12 are respectively disposed become low-temperature portions. Consequently, an electromotive force due to the Seebeck effect is generated between the central portion of the electromagnetic wave absorbing layer 13 and the ends where the first electrode 11 and the second electrode 12 are respectively disposed.

[0096] For example, when the second electrode 12 contains a material with a higher thermal conductivity than the first electrode 11, the end of the electromagnetic wave absorbing layer 13 where the second electrode 12 is disposed has a lower temperature than the end where the first electrode 11 is disposed. In this case, the electromotive force generated between the central portion of the electromagnetic wave absorbing layer 13 and the end where the second electrode 12 is disposed is greater than the electromotive force generated between the central portion of the electromagnetic wave absorbing layer 13 and the end where the first electrode 11 is disposed. Therefore, based on the difference in electromotive force between the central portion of the electromagnetic wave absorbing layer 13 and the respective ends where the first electrode 11 and the second electrode 12 are disposed, the electromagnetic wave detection device 10 according to the first comparative example is able to detect the incident electromagnetic wave EM on the electromagnetic wave absorbing layer 13.

[0097] However, in the electromagnetic wave detection device 10, the electromotive force between the central portion of the electromagnetic wave absorbing layer 13 and the ends where the first electrode 11 and the second electrode 12 are respectively disposed cancel each other out, resulting in a decrease in detection sensitivity. Furthermore, in the electromagnetic wave detection device 10, the first electrode 11 and the second electrode 12 are disposed on the first main surface of the electromagnetic wave absorbing layer 13 constituting the pixel. Therefore, the aperture ratio of the electromagnetic wave absorbing layer 13 in each pixel is reduced by an amount corresponding to that of the first electrode 11 and the second electrode 12.

[0098] in addition, Figure 5A This is a perspective view of the configuration of the electromagnetic wave detection device 20 based on the second comparative example. Figure 5B It is shown Figure 5A A schematic diagram of the energy of the electromagnetic wave absorbing layer 23 in the electromagnetic wave detection device 20 shown.

[0099] like Figure 5AAs shown, the electromagnetic wave detection device 20 according to the second comparative example is constructed by arranging a first electrode 21 and a second electrode 22, which are separated from each other, on one main surface of the electromagnetic wave absorbing layer 23. In the second comparative example, the first electrode 21 and the second electrode 22 contain the same conductive material, and the electromagnetic wave absorbing layer 23 is configured as a heterojunction layer comprising a p-type semiconductor layer 23p and an n-type semiconductor layer 23n bonded together.

[0100] Here, as Figure 5B As shown, the heat generated by the electromagnetic wave absorbing layer 23, which absorbs electromagnetic waves (EM), diffuses to the first electrode 21 and the second electrode 22. Therefore, in the electromagnetic wave absorbing layer 23, the central portion near the junction of the p-type semiconductor layer 23p and the n-type semiconductor layer 23n becomes a high-temperature portion, while the ends where the first electrode 21 and the second electrode 22 are respectively disposed become low-temperature portions. Thus, an electromotive force due to the Seebeck effect is generated between the central portion of the electromagnetic wave absorbing layer 23 and the ends where the first electrode 21 and the second electrode 22 are respectively disposed.

[0101] At this time, in the p-type semiconductor layer 23p, an electromotive force is generated that causes the end where the first electrode 21 is disposed to have a higher potential than the central portion near the junction surface. Conversely, in the n-type semiconductor layer 23n, an electromotive force is generated that causes the end where the second electrode 22 is disposed to have a lower potential than the central portion near the junction surface. Therefore, the electromagnetic wave detection device 20 according to the second comparative example can align the direction of the electromotive force throughout the entire electromagnetic wave absorbing layer 23. This allows the detection of the incident electromagnetic wave EM on the electromagnetic wave absorbing layer 23 based on the sum of the electromotive forces generated between the ends where the first electrode 21 and the second electrode 22 are respectively disposed.

[0102] In the electromagnetic wave detection device 20 according to the second comparative example, no mutual cancellation of electromotive forces occurs between the electromagnetic wave absorbing layer 23 and the first electrode 11 and the second electrode 12 respectively. This improves the detection sensitivity compared to the electromagnetic wave detection device 10 according to the first comparative example. However, in the electromagnetic wave absorbing layer 23 containing low-dimensional electronic materials, it is difficult to form an electromagnetic wave absorbing layer 23 comprising a p-type semiconductor layer 23p and an n-type semiconductor layer 23n bonded together in the in-plane direction.

[0103] For example, when the electromagnetic wave absorbing layer 23 contains carbon nanotubes as a low-dimensional electronic material, in order to change the carbon nanotubes, which are p-type semiconductors, into n-type semiconductors, the carbon nanotubes are modified by using a wet process such as crown ether. However, it is very difficult to change a portion of the electromagnetic wave absorbing layer 23 provided for each pixel into an n-type semiconductor layer 23n by using a wet process to prevent variations between pixels.

[0104] In contrast, in the electromagnetic wave detection device 100 according to this embodiment, a temperature gradient can be formed in the thickness direction of the electromagnetic wave absorbing layer 130, and the electromotive force generated by the temperature gradient can be extracted by a first electrode 110 disposed on a first main surface of the electromagnetic wave absorbing layer 130 and a second electrode 120 disposed on a second main surface of the electromagnetic wave absorbing layer 130 opposite to the first main surface.

[0105] With this configuration, the electromagnetic wave detection device 100 according to this embodiment does not experience the mutual cancellation of electromotive forces generated by temperature gradients, as is the case in the electromagnetic wave detection device 10 according to the first comparative example. This improves the detection sensitivity of electromagnetic waves (EM). Furthermore, in the electromagnetic wave detection device 100 according to this embodiment, each opening 111 provided for the first electrode 110 serves as a pixel. This allows for a very high aperture ratio in each pixel. Moreover, in the electromagnetic wave detection device 100 according to this embodiment, unlike the electromagnetic wave detection device 20 according to the second comparative example, no heterogeneous bonding is formed in the electromagnetic wave absorbing layer 23. This helps to suppress the increase in manufacturing difficulty.

[0106] As described above, in the electromagnetic wave detection device 100 according to this embodiment, the reduction in aperture ratio in each pixel can be suppressed, and the increase in manufacturing difficulty can be suppressed. Therefore, this embodiment can provide an electromagnetic wave detection device 100 with a structure suitable for further improving performance or reducing cost.

[0107] <2. Second Implementation Plan>

[0108] Next, refer to Figures 6-7B This describes the configuration of the electromagnetic wave detection device according to the second embodiment of this disclosure. Figure 6 This is a schematic diagram showing the cross-sectional configuration of the electromagnetic wave detection device 200 according to this embodiment.

[0109] like Figure 6 As shown, for example, the electromagnetic wave detection device 200 includes an electromagnetic wave absorbing layer 230, a first electrode 210, a second electrode 220, an insulating layer 240, and a buffer layer 250. Note that the electromagnetic wave absorbing layer 230, the first electrode 210, the second electrode 220, and the insulating layer 240 are substantially similar to those in the reference design. Figure 1 The electromagnetic wave absorbing layer 130, the first electrode 110, the second electrode 120, and the insulating layer 140 are described herein, and therefore their descriptions are omitted here.

[0110] A buffer layer 250 is disposed between the electromagnetic wave absorbing layer 230 and the second electrode 220. Specifically, the buffer layer 250 is configured to be sandwiched in the stacking direction between the electromagnetic wave absorbing layer 230 and the second electrode 220. The buffer layer 250 is configured to suppress noise generated due to the inflow of charge carriers from the second electrode 220 into the electromagnetic wave absorbing layer 230.

[0111] For example, as an operating mode, the electromagnetic wave detection device 200 has a mode in which a voltage is applied to the first electrode 210 and charge carriers are sequentially extracted from the second electrode 220 without saturating the electromotive force due to heat. With this configuration, the electromagnetic wave detection device 200 can perform signal processing such as amplification on the extracted charge carriers by accumulating the extracted charge carriers in a floating diffusion section or the like.

[0112] However, the extracted charge carriers can flow back into the electromagnetic wave absorbing layer 230 via the second electrode 220, causing noise. In the electromagnetic wave detection device 200 according to this embodiment, noise generation can be suppressed by providing a buffer layer 250 between the electromagnetic wave absorbing layer 230 and the second electrode 220 to suppress the inflow of charge carriers.

[0113] The buffer layer 250 can achieve the above function by appropriately setting its energy level relative to the electromagnetic wave absorbing layer 230.

[0114] here, Figure 7A and Figure 7B The relationship between the energy levels of the buffer layer 250 and the electromagnetic wave absorbing layer 230 used to achieve the above functions is shown. Figure 7A This is an energy diagram showing the relationship between the energy levels of the buffer layer 250 and the electromagnetic wave absorbing layer 230 when the electromagnetic wave absorbing layer 230 is an n-type semiconductor layer. Figure 7B This is an energy diagram showing the relationship between the energy levels of the buffer layer 250 and the electromagnetic wave absorbing layer 230 when the electromagnetic wave absorbing layer 230 is a p-type semiconductor layer.

[0115] like Figure 7A As shown, when the electromagnetic wave absorbing layer 230 is an n-type semiconductor layer, the energy level 250n of the buffer layer 250 can be set to be deeper than the energy level 230n of the electromagnetic wave absorbing layer 230 (i.e., having a larger absolute value). Specifically, the buffer layer 250 can be set to have an ionization potential larger than that of the electromagnetic wave absorbing layer 230. For example, the ionization potential of the buffer layer 250 corresponds to the lower end of the energy level 250n of the buffer layer 250. With this configuration, the buffer layer 250 can act as a barrier to prevent holes 95 from flowing from the second electrode 220 into the electromagnetic wave absorbing layer 230.

[0116] In the case where the electromagnetic wave absorbing layer 230 contains carbon nanotubes of n-type semiconductor, for example, such a buffer layer 250 can be formed by containing ZnO, PEDOT-PSS, TPBi, α-TPD, α-NPD, β-NPD, CBP, Spiro-OMETAD, etc. as buffer materials.

[0117] In addition, such as Figure 7B As shown, when the electromagnetic wave absorbing layer 230 is a p-type semiconductor layer, the energy level 250p of the buffer layer 250 can be set to be shallower than the energy level 230p of the electromagnetic wave absorbing layer 230 (i.e., having a smaller absolute value). Specifically, the buffer layer 250 can be set to have a smaller electron affinity than the electromagnetic wave absorbing layer 230. For example, the electron affinity of the buffer layer 250 corresponds to the upper end of the energy level 250p of the buffer layer 250. With this configuration, the buffer layer 250 can act as a barrier to prevent electrons 96 from flowing from the second electrode 220 into the electromagnetic wave absorbing layer 230.

[0118] When the electromagnetic wave absorbing layer 230 contains carbon nanotubes of p-type semiconductor, for example, such a buffer layer 250 can be formed by containing BPhen, NBPhen, B3PyMPM, DCB3T, Bpy-OXD, Bpy-FOXD, 3TPYMB, BP4MPY, BmPyPB, (Alq)3, TAZ, Spiro-OXDAZ, DBimiBPhen, HNBPhen, Spiro-2NPB, etc. as buffer materials.

[0119] In the electromagnetic wave detection device 200 according to this embodiment, which has the above-described configuration, noise generated due to charge carriers flowing from the second electrode 220 into the electromagnetic wave absorption layer 230 can be suppressed in the operating mode of applying a voltage to the first electrode 210.

[0120] <3. Third Implementation Plan>

[0121] Next, refer to Figure 8 This describes the configuration of the electromagnetic wave detection device according to the third embodiment of this disclosure. Figure 8 This is a schematic diagram showing the cross-section and top surface configuration of the electromagnetic wave detection device 300 according to this embodiment.

[0122] like Figure 8 As shown, for example, the electromagnetic wave detection device 300 includes an electromagnetic wave absorbing layer 330, a first electrode 310, a second electrode 320, an insulating layer 340, and a shielding electrode 360. Note that the electromagnetic wave absorbing layer 330, the first electrode 310, the second electrode 320, and the insulating layer 340 are substantially similar to those in the reference design. Figure 1The electromagnetic wave absorbing layer 130, the first electrode 110, the second electrode 120, and the insulating layer 140 are described herein, and therefore their descriptions are omitted here.

[0123] The shielding electrode 360 ​​can be disposed on the second main surface of the electromagnetic wave absorbing layer 330 between the second electrodes 320 using a conductive material. Specifically, the shielding electrode 360 ​​can be configured using a conductive material to form a lattice shape around each of the second electrodes 320. With this configuration, the shielding electrode 360 ​​can suppress capacitive coupling between adjacent second electrodes 320, which can suppress electrical crosstalk between adjacent second electrodes 320.

[0124] Furthermore, the shielding electrode 360 ​​can suppress the cross-pixel effect of heat generated by the electromagnetic wave absorption layer 330 (i.e., thermal crosstalk) by absorbing electromagnetic waves EM. Specifically, the shielding electrode 360 ​​can suppress the spread of heat to adjacent pixels by releasing the heat spread from the pixels that have absorbed electromagnetic waves EM between pixels.

[0125] For example, shielding electrode 360 ​​may comprise the same conductive material as the second electrode 320. In this case, shielding electrode 360 ​​may be formed on the second main surface of electromagnetic wave absorbing layer 330 through the same process as the second electrode 320. For example, shielding electrode 360 ​​may comprise a conductive material comprising Ti. Alternatively, shielding electrode 360 ​​may comprise the same conductive material as other wiring or electrodes. For example, shielding electrode 360 ​​may comprise a conductive material comprising aluminum (Al), tungsten (W), gold (Au), or copper (Cu).

[0126] In the electromagnetic wave detection device 300 according to this embodiment with the above-described configuration, by providing a shielding electrode 360 ​​between the second electrodes 320, electrical crosstalk or thermal crosstalk between pixels can be suppressed.

[0127] <4. Fourth Implementation Plan>

[0128] (4.1. Composition of Electromagnetic Wave Detection Device)

[0129] Next, refer to Figure 9 This describes the configuration of the electromagnetic wave detection device according to the fourth embodiment of this disclosure. Figure 9 This is a schematic diagram showing the cross-sectional configuration of the electromagnetic wave detection device 400 according to this embodiment.

[0130] like Figure 9As shown, for example, the electromagnetic wave detection device 400 includes an electromagnetic wave absorbing layer 430, a first electrode 410, a second electrode 420, an insulating layer 440, and a heat insulation portion 470. Furthermore, a readout circuit (not shown) is disposed further below the heat insulation portion 470 (i.e., on the side opposite to the side where the second electrode 420 is disposed, relative to the heat insulation portion 470). Note that the electromagnetic wave absorbing layer 430, the first electrode 410, the second electrode 420, and the insulating layer 440 are substantially similar to those in the reference design. Figure 1 The electromagnetic wave absorbing layer 130, the first electrode 110, the second electrode 120, and the insulating layer 440 are described herein, and therefore their descriptions are omitted here.

[0131] A heat insulation portion 470 is disposed below the electromagnetic wave absorbing layer 430 and the second electrode 420. The heat insulation portion 470 thermally separates the electromagnetic wave absorbing layer 430 and a readout circuit (not shown) disposed below the heat insulation portion 470. Specifically, the heat insulation portion 470 includes a first layer 471 disposed on the second main surface of the electromagnetic wave absorbing layer 430, a second layer 472 disposed below the first layer 471 to include a gap 475, and a third layer 473 disposed below the second layer. Because the interior of the gap 475 is a vacuum or air with low thermal conductivity, the heat insulation portion 470 can thermally separate the electromagnetic wave absorbing layer 430 disposed on the upper and lower sides from the readout circuit (not shown) through the heat insulation portion 470.

[0132] The first layer 471, second layer 472, and third layer 473 included in the insulation portion 470 may contain insulating material. Specifically, the first layer 471 and third layer 473, along with the second layer 472, may contain insulating materials having different etch rates than each other. With this configuration, when forming voids 475 in the second layer 472 by etching, the first layer 471 and third layer 473 can be used as etch stop layers. This makes it easier to form larger voids 475 in the second layer 472. For example, the second layer 472 may contain silicon oxide (SiO2). x In the case of ), the first layer 471 and the third layer 473 may contain silicon nitride (SiN). x ).

[0133] In the electromagnetic wave detection device 400 according to this embodiment, which has the above-described configuration, thermal coupling between the electromagnetic wave absorbing layer 430 and the readout circuit with a large heat capacity can be suppressed by the heat insulation portion 470. Therefore, the electromagnetic wave detection device 400 can control the temperature gradient in the thickness direction of the electromagnetic wave absorbing layer 430 with higher precision.

[0134] (4.2. Methods for forming the insulation)

[0135] Here, refer to Figures 10A to 10E The method for forming the heat insulation part 470 in the electromagnetic wave detection device 400 according to this embodiment is explained. Figures 10A to 10E This is a longitudinal cross-sectional view of each step of the method for forming the insulating part 470 in the electromagnetic wave detection device 400 according to this embodiment. Figures 10A to 10E The diagram of the structure above the second electrode 420 is omitted.

[0136] First, such as Figure 10A As shown, it forms a structure in which SiN is stacked. x The first layer 471 contains SiO x The second layer 472 and containing SiN x The third layer 473 is a stacked structure. In addition, a second electrode 420 is formed on the first layer 471.

[0137] Next, as Figure 10B As shown, by using a patterned resist 474, anisotropic etching is performed on the first layer 471 between the second electrodes 420 from the side of the second electrode 420, thereby forming an opening 474A that penetrates the first layer 471 to reach the second layer 472.

[0138] Subsequently, as Figure 10C As shown, isotropic etching is performed on the second layer 472 by introducing an aqueous solution of hydrogen fluoride (HF) through opening 474A into the second layer 472. This is because the second layer 472 contains SiO₂. x The SiN content in HF is higher than that in the first layer 471 and the third layer 473. x The faster etching rate allows for selective etching of the second layer 472. Note that the etching method for the second layer 472 is not limited to the etching using an aqueous hydrogen fluoride solution described above. For example, the etching method for the second layer 472 could be on SiO₂... x and SiN x Selective dry etching between them.

[0139] Next, as Figure 10D As shown, the resist 474 is removed after etching the second layer 472. Subsequently, a SiO2-containing layer is formed along the surface shape of the second electrode 420 and the first layer 471 using ALD (Atomic Layer Deposition). x A barrier layer 476 is formed to block the opening 474A. Therefore, a void 475 is formed inside the second layer 472.

[0140] Subsequently, as Figure 10E As shown, by removing the barrier layer 476 deposited on the second electrode 420 and the first layer 471, a heat-insulating portion 470 can be formed below the second electrode 420. Subsequently, an electromagnetic wave absorbing layer 430 can be formed by coating carbon nanotubes onto the second electrode 420 and the first layer 471. Furthermore, a first electrode 410 and an insulating layer 440 can be sequentially formed on the electromagnetic wave absorbing layer 430.

[0141] <5. Fifth Implementation Plan>

[0142] (5.1. Composition of Electromagnetic Wave Detection Device)

[0143] Next, refer to Figure 11 This describes the configuration of the electromagnetic wave detection device according to the fifth embodiment of this disclosure. Figure 11 This is a schematic diagram showing the cross-sectional configuration of the electromagnetic wave detection device 500 according to this embodiment.

[0144] like Figure 11 As shown, for example, the electromagnetic wave detection device 500 includes an electromagnetic wave absorbing layer 530, a first electrode 510, a second electrode 520, an insulating layer 540, a pixel separation layer 541, and a connection via 580. Note that the electromagnetic wave absorbing layer 530, the first electrode 510, the second electrode 520, and the insulating layer 540 are substantially similar to those in the reference design. Figure 1 The electromagnetic wave absorbing layer 130, the first electrode 110, the second electrode 120, and the insulating layer 140 are described herein, and therefore their descriptions are omitted here.

[0145] The pixel separation layer 541 is formed by using an insulating material to penetrate the electromagnetic wave absorption layer 530 between pixels in the thickness direction. Specifically, the pixel separation layer 541 can be configured to penetrate the electromagnetic wave absorption layer 530 in the region between the second electrodes 520 in the thickness direction. By separating the electromagnetic wave absorption layer 530 for each pixel, the pixel separation layer 541 can suppress thermal crosstalk between adjacent pixels.

[0146] For example, the pixel separation layer 541 may contain an insulating material similar to that of the insulating layer 540. In this case, the pixel separation layer 541 can be formed using the same process as the insulating layer 540. Alternatively, the pixel separation layer 541 may contain a material with a lower thermal conductivity than the electromagnetic wave absorbing layer 530. In this case, the pixel separation layer 541 can more reliably separate the pixels of the electromagnetic wave absorbing layer 530.

[0147] In the electromagnetic wave detection apparatus 500 according to this embodiment, the insulating layer 540 and the pixel separation layer 541 are formed simultaneously and are therefore configured to cover the entire first main surface of the electromagnetic wave absorbing layer 530. Thus, the first electrode 510 is electrically connected to the electromagnetic wave absorbing layer 530 via a connection via 580 disposed on and penetrating the insulating layer 540. For example, the connection via 580 may contain a conductive material such as aluminum (Al), titanium (Ti), titanium nitride (TiN), tungsten (W), nickel (Ni), or copper (Cu).

[0148] In the electromagnetic wave detection device 500 according to this embodiment with the above-described configuration, the electromagnetic wave absorption layer 530 can be physically separated for each pixel by the pixel separation layer 541, which can further suppress electrical or thermal crosstalk between pixels.

[0149] (5.2. Manufacturing method of electromagnetic wave detection device)

[0150] Here, refer to Figures 12A to 12F The manufacturing method of the electromagnetic wave detection device 500 according to this embodiment is explained. Figures 12A to 12F This is a longitudinal cross-sectional view of each step of the manufacturing method of the electromagnetic wave detection device 500 according to this embodiment.

[0151] First, such as Figure 12A As shown, an electromagnetic wave absorbing layer 530 is formed by coating carbon nanotubes onto a second electrode 520 that is separate for each pixel.

[0152] Next, as Figure 12B As shown, anisotropic etching is performed on the electromagnetic wave absorbing layer 530 between the second electrodes 520 by using a patterned resist 591 to form an opening 592 through the electromagnetic wave absorbing layer 530.

[0153] Subsequently, as Figure 12C As shown, the patterned resist 591 on the electromagnetic wave absorbing layer 530 is removed.

[0154] In addition, such as Figure 12D As shown, SiO2 is deposited on the electromagnetic wave absorbing layer 530 using the ALD method. x A pixel separation layer 541 is formed to fill the opening 592, and an insulating layer 540 is formed on the electromagnetic wave absorption layer 530.

[0155] Next, as Figure 12E As shown, the insulating layer 540 on the electromagnetic wave absorbing layer 530 is anisotropically etched using a patterned resist 593 to form an opening 594 through the insulating layer 540.

[0156] Subsequently, as Figure 12F As shown, a connection via 580 is formed by filling the opening 594 with a conductive material, and then a first electrode 510 is formed on the connection via 580. This forms a first electrode 510 that is electrically connected to the electromagnetic wave absorbing layer 530.

[0157] <6. Application Examples>

[0158] In the following description, reference will be made to Figures 13-16This description illustrates an applicable example of an electromagnetic wave detection device according to one embodiment of the present disclosure. Although the following description illustrates electromagnetic wave detection device 100 as an electromagnetic wave detection device according to one embodiment of the present disclosure, it is understood that this also applies to electromagnetic wave detection devices 200, 300, 400, and 500.

[0159] (Applicability to imaging systems)

[0160] First, refer to Figure 13 and Figure 14 This invention illustrates an example of an electromagnetic wave detection device 100 according to one embodiment of the present disclosure, applicable to an imaging system. Figure 13 This is an example illustrating the outline configuration of an electromagnetic wave detection system 600 including an electromagnetic wave detection device 100 according to one embodiment of the present disclosure. Figure 14 An example flowchart of the imaging operation in the electromagnetic wave detection system 600 is shown.

[0161] like Figure 13 As shown, for example, the electromagnetic wave detection system 600 is a camera system that generates an electromagnetic wave image of an object by detecting electromagnetic waves EM emitted from the object by the electromagnetic wave detection device 100.

[0162] For example, the electromagnetic wave detection system 600 includes an optical system 601, a shutter 602, an electromagnetic wave detection device 100 according to one embodiment of the present disclosure, a processor 603, a display 604, an operation unit 605, a frame memory 606, a memory 607, and a power supply unit 608. In the electromagnetic wave detection system 600, the electromagnetic wave detection device 100, the processor 603, the display 604, the operation unit 605, the frame memory 606, the memory 607, and the power supply unit 608 are interconnected via a bus 610.

[0163] The electromagnetic wave detection device 100 detects electromagnetic waves that have passed through the optical system 601 and the shutter 602, and outputs image data corresponding to the detected electromagnetic waves. Specifically, the electromagnetic wave detection device 100 acquires a reference signal when the shutter 602 is closed, which controls whether the electromagnetic wave detection device 100 is irradiated by electromagnetic waves, and acquires a signal when the shutter 602 is open, as an imaging signal. The electromagnetic wave detection device 100 outputs an image data signal obtained by subtracting the reference signal when the shutter 602 is closed from the imaging signal when the shutter 602 is open.

[0164] Processor 603 is a signal processing circuit that processes the signals (i.e., image data) output from electromagnetic wave detection device 100. Frame memory 606 temporarily stores the image data processed by processor 603 in frames. For example, display 604 includes a panel-type display device such as a liquid crystal panel or an organic EL (electroluminescent) panel, and displays the image data generated by electromagnetic wave detection device 100. Memory 607 includes a recording medium such as a semiconductor memory or a hard disk, and records the image data generated by electromagnetic wave detection device 100 thereon. Operation unit 605 outputs operation commands for various functions of electromagnetic wave detection system 600 according to user operations. Power supply unit 608 includes various power supplies that provide operating power to electromagnetic wave detection device 100, processor 603, display 604, operation unit 605, frame memory 606, and memory 607.

[0165] Next, the imaging process in the electromagnetic wave detection system 600 will be explained. First, imaging begins through the user operation unit 605.

[0166] At this time, as Figure 14 As shown, the electromagnetic wave detection system 600 places the shutter 602 in a closed state (S101) and obtains a reference signal from the electromagnetic wave detection device 100 in a state where the electromagnetic wave detection device 100 is not irradiated by electromagnetic waves (EM) as a reference signal (S103). Subsequently, the electromagnetic wave detection system 600 places the shutter 602 in an open state (S105) and obtains an imaging signal from the electromagnetic wave detection device 100 in a state where the electromagnetic wave detection device 100 is irradiated by electromagnetic waves (EM) as an imaging signal (S107). Then, the electromagnetic wave detection system 600 generates image data by subtracting the reference signal in the closed state from the imaging signal in the open state (S109). Next, the processor 603 performs predetermined signal processing (e.g., noise reduction processing) on ​​the image data output from the electromagnetic wave detection device 100 (S111). The processor 603 causes the frame memory 606 to hold the image data after predetermined signal processing. Thereafter, the frame memory 606 causes the memory 607 to store the image data (S113). Imaging in the electromagnetic wave detection system 600 is performed according to the above procedure.

[0167] In this applicable example, the electromagnetic wave detection device 100 according to one embodiment of this disclosure is suitable for the electromagnetic wave detection system 600. For example, the electromagnetic wave detection system 600 can be used in a non-destructive testing camera system or a thermal imaging camera system.

[0168] (Applicability to mobile body control systems)

[0169] The technology disclosed herein (the Technology) can be applied to a variety of products. For example, the Technology disclosed herein can be implemented as a device installed on any type of mobile body such as a car, electric car, hybrid electric car, motorcycle, bicycle, personal mobility device, airplane, unmanned aerial vehicle, ship or robot.

[0170] Figure 15 This is a block diagram illustrating a schematic configuration example of a vehicle control system, which is an example of a mobile body control system to which the technology according to an embodiment of the present disclosure is applicable.

[0171] The vehicle control system 12000 includes multiple electronic control units interconnected via a communication network 12001. Figure 15 In the example shown, the vehicle control system 12000 includes a drive system control unit 12010, a main system control unit 12020, an external information detection unit 12030, an internal information detection unit 12040, and a comprehensive control unit 12050. Furthermore, as functional components of the comprehensive control unit 12050, a microcomputer 12051, an audio / image output unit 12052, and an in-vehicle network interface (I / F) 12053 are shown.

[0172] The drive system control unit 12010 controls the operation of devices related to the vehicle's drive system according to various programs. For example, the drive system control unit 12010 is used as a control device for a drive force generating device for generating drive force for a vehicle such as an internal combustion engine or a drive motor, a drive force transmission mechanism for transmitting drive force to the wheels, a steering mechanism for adjusting the vehicle's steering angle, and a braking device for generating braking force for the vehicle.

[0173] The main system control unit 12020 controls the operation of various devices installed on the vehicle body according to various programs. For example, the main system control unit 12020 is used as a control device for keyless entry systems, smart key systems, power windows, or various lights such as headlights, taillights, brake lights, turn signals, and fog lights. In this case, radio waves transmitted from a portable device or signals from various types of switches, instead of buttons, can be input to the main system control unit 12020. The main system control unit 12020 receives these input radio waves or signals and controls the vehicle's door locking devices, power windows, lights, etc.

[0174] The exterior information detection unit 12030 detects information related to the exterior of the vehicle, including information from the vehicle control system 12000. For example, the exterior information detection unit 12030 is connected to an imaging unit 12031. The exterior information detection unit 12030 causes the imaging unit 12031 to image the exterior of the vehicle and receives the image. Based on the received image, the exterior information detection unit 12030 can perform processing such as detecting objects like people, cars, obstacles, signs, and text on the road, or detecting their distance.

[0175] Imaging unit 12031 is an optical sensor that receives light, and its output is an electrical signal corresponding to the amount of light received. Imaging unit 12031 can output an electrical signal as an image, or it can output an electrical signal as information related to distance measurement. In addition, the light received by imaging unit 12031 can be visible light or invisible light such as infrared light.

[0176] The in-vehicle information detection unit 12040 detects information related to the interior of the vehicle. For example, the in-vehicle information detection unit 12040 is connected to a driver state detection unit 12041 that detects the driver's state. For example, the driver state detection unit 12041 includes a camera that images the driver. Based on the detection information input from the driver state detection unit 12041, the in-vehicle information detection unit 12040 can calculate the driver's fatigue level or concentration level, or determine whether the driver has fallen asleep.

[0177] The microcomputer 12051 can calculate control target values ​​for the drive force generating device, steering mechanism, or braking device based on information about the vehicle's interior or exterior obtained by the external information detection unit 12030 or the internal information detection unit 12040, and can output control commands to the drive system control unit 12010. For example, the microcomputer 12051 can perform coordinated control to implement functions of advanced driver assistance systems (ADAS), including collision avoidance or mitigation, following distance-based tracking, speed maintenance, collision warning, and lane departure warning.

[0178] In addition, the microcomputer 12051 can coordinate and control the drive force generating device, steering mechanism, braking device, etc., based on information about the exterior or interior of the vehicle obtained by the external information detection unit 12030 or the internal information detection unit 12040, aiming to achieve autonomous driving without relying on the driver's operation.

[0179] Furthermore, the microcomputer 12051 can output control commands to the main system control unit 12020 based on information about the exterior of the vehicle obtained by the vehicle exterior information detection unit 12030. For example, the microcomputer 12051 can perform coordinated control aimed at preventing glare by controlling the headlights according to the position of the vehicle in front or oncoming vehicles detected by the vehicle exterior information detection unit 12030, such as changing the high beams to low beams.

[0180] The sound / image output unit 12052 transmits an output signal of at least one of sound and image to an output device capable of visually or audibly informing vehicle occupants or the outside of the vehicle. Figure 15 In the example, an audio speaker 12061, a display unit 12062, and a dashboard 12063 are shown as output devices. For example, the display unit 12062 may include at least one of an in-vehicle display and a head-up display.

[0181] Figure 16 This is a diagram showing an example of the mounting location of the imaging unit 12031.

[0182] exist Figure 16 In the imaging unit 12031, imaging units 12101, 12102, 12103, 12104 and 12105 are included.

[0183] For example, imaging units 12101, 12102, 12103, 12104, and 12105 are located at the front of the vehicle 12100, the side mirrors, the rear bumper, and the rear door, as well as on the upper side of the windshield inside the vehicle. Imaging unit 12101 at the front of the vehicle and imaging unit 12105 on the upper side of the windshield inside the vehicle primarily acquire images of the front of the vehicle 12100. Imaging units 12102 and 12103 in the side mirrors primarily acquire images of the sides of the vehicle 12100. Imaging unit 12104 on the rear bumper or rear door primarily acquires images of the rear of the vehicle 12100. Imaging unit 12105 on the upper side of the windshield inside the vehicle is mainly used to detect vehicles, pedestrians, obstacles, traffic lights, traffic signs, lanes, etc., ahead.

[0184] also, Figure 16An example of the imaging range of imaging units 12101 to 12104 is shown. Imaging range 12111 represents the imaging range of imaging unit 12101 located at the front of the vehicle. Imaging ranges 12112 and 12113 represent the imaging ranges of imaging units 12102 and 12103 located in the side mirrors, respectively. Imaging range 12114 represents the imaging range of imaging unit 12104 located in the rear bumper or rear door. For example, a bird's-eye view of vehicle 12100 is obtained by overlaying image data captured by imaging units 12101 to 12104.

[0185] At least one of the imaging units 12101 to 12104 may have the function of acquiring distance information. For example, at least one of the imaging units 12101 to 12104 may be a stereo camera composed of multiple imaging elements, or may be an imaging element with pixels for phase difference detection.

[0186] For example, based on distance information obtained from imaging units 12101 to 12104, microcomputer 12051 can determine the distance to each three-dimensional object within the imaging range 12111 to 12114 and the time change of that distance (relative speed relative to vehicle 12100), thereby extracting the closest three-dimensional object that exists on the driving path of vehicle 12100 and is traveling in approximately the same direction as vehicle 12100 at a predetermined speed (e.g., 0 km / h or higher) as the vehicle in front. Furthermore, microcomputer 12051 can set a pre-determined following distance in front of the vehicle in front and perform automatic braking control (including tracking stop control), automatic acceleration control (including tracking start control), etc. Therefore, coordinated control aimed at achieving autonomous driving, etc., can be performed.

[0187] For example, based on distance information obtained from imaging units 12101-12104, microcomputer 12051 can classify three-dimensional object data into three-dimensional object data for two-wheeled vehicles, ordinary vehicles, large vehicles, pedestrians, utility poles, and other three-dimensional objects, extract the classified three-dimensional object data, and use the extracted three-dimensional object data for automatic obstacle avoidance. For example, microcomputer 12051 identifies obstacles around vehicle 12100 as obstacles that the driver of vehicle 12100 can visually recognize and obstacles that are difficult for the driver of vehicle 12100 to visually recognize. Then, microcomputer 12051 determines the collision risk, indicating the degree of danger of collision with each obstacle. If the collision risk is equal to or higher than a set value and therefore there is a possibility of collision, microcomputer 12051 outputs a warning to the driver via audio speaker 12061 or display unit 12062, and performs forced deceleration or evasive steering via drive system control unit 12010. Therefore, microcomputer 12051 can assist driving to avoid collisions.

[0188] At least one of the imaging units 12101 to 12104 can be an infrared camera that detects infrared light. For example, the microcomputer 12051 can identify a pedestrian by determining whether a pedestrian exists in the imaging images of the imaging units 12101 to 12104. This pedestrian identification is performed, for example, by extracting feature points from the imaging images of the imaging units 12101 to 12104, which are infrared cameras, and by performing pattern matching processing on a series of feature points representing the outline of an object to determine whether it is a pedestrian. When the microcomputer 12051 determines that a pedestrian exists in the imaging images of the imaging units 12101 to 12104 and thus identifies the pedestrian, the sound / image output unit 12052 controls the display unit 12062 to display a rectangular outline for emphasis, superimposed on the identified pedestrian. The sound / image output unit 12052 can also control the display unit 12062 to display an icon or similar indicating the pedestrian at a desired location.

[0189] The above describes examples of mobile body control systems applicable to the technology disclosed herein. The technology disclosed herein is applicable to the imaging unit 12031 configured as described above. The technology disclosed herein can detect light or electromagnetic waves other than visible light, which are invisible to humans. This enables the mobile body control system to perform more advanced control using the detection results. Furthermore, the technology disclosed herein can further improve the performance or reduce the cost of the electromagnetic wave detection device 100 that detects light or electromagnetic waves other than visible light. This enables the electromagnetic wave detection device 100 to be applied to a wider range of targets.

[0190] The technology according to this disclosure has been described above with reference to the first to fifth embodiments. However, the technology according to this disclosure is not limited to the above embodiments and can be modified in various ways. In addition, the first to fifth embodiments described above can be combined with each other.

[0191] Furthermore, not all the components and operations described in the embodiments are essential to the components and operations of this disclosure. For example, among the components of the embodiments, components not described in the independent claim that references the highest concept of this disclosure should be understood as optional components.

[0192] Terms used throughout this specification and the appended claims should be interpreted as “non-limiting” terms. For example, the terms “comprising” or “including” should be interpreted as “not limited to what is described as included.” The term “having” should be interpreted as “not limited to what is described as having.”

[0193] The terminology used in this specification includes terms used for illustrative purposes only and not for limiting the structure and operation. For example, terms such as “right,” “left,” “up,” and “down” indicate directions only in the referenced figures. Furthermore, the terms “inner” and “outer” indicate directions only toward and away from the center of the feature of interest, respectively. This also applies to terms similar to these and terms serving the same purpose.

[0194] Note that the technology according to this disclosure can have the following configuration. The technology according to this disclosure with the following configuration can generate a temperature gradient along the thickness direction of the electromagnetic wave absorbing layer, thereby converting the temperature gradient generated along the thickness direction of the electromagnetic wave absorbing layer thermoelectrically into an electromotive force. Therefore, in the electromagnetic wave detection device using the technology according to this disclosure, compared to the case where the temperature gradient generated in the in-plane direction of the electromagnetic wave absorbing layer is thermoelectrically converted, an efficient structure can be used to convert the temperature gradient thermoelectrically into an electromotive force. Therefore, the electromagnetic wave detection device using the technology according to this disclosure can achieve further performance improvements or cost reductions. The effects of the technology according to this disclosure are not necessarily limited to those described herein, and can be any of the effects described in this disclosure.

[0195] (1) An electromagnetic wave detection device, comprising:

[0196] Electromagnetic wave absorbing layer, which contains low-dimensional electronic materials that absorb electromagnetic waves;

[0197] The first electrode is disposed on the first main surface of the electromagnetic wave absorbing layer;

[0198] The second electrode is disposed on the second main surface of the electromagnetic wave absorbing layer opposite to the first main surface; and

[0199] The readout circuit reads from the second electrode the signal generated by the thermoelectric conversion through the heat generated by the electromagnetic wave absorbing layer that absorbs the electromagnetic wave.

[0200] (2) The electromagnetic wave detection device according to (1), wherein,

[0201] The first electrode is configured to cover the entire first main surface, and

[0202] The first electrode has multiple openings arranged in a two-dimensional pattern.

[0203] (3) The electromagnetic wave detection device according to (2), wherein each of the plurality of openings constitutes a pixel for detecting electromagnetic waves incident from the first main surface side.

[0204] (4) The electromagnetic wave detection device according to (2) or (3), wherein the second electrode is configured to be separated from each other in the region of the second main surface corresponding to the plurality of openings.

[0205] (5) The electromagnetic wave detection device according to any one of (2) to (4), wherein a pixel separation layer is further provided to separate the electromagnetic wave absorption layer for each region provided with the plurality of openings.

[0206] (6) The electromagnetic wave detection device according to (5), wherein the pixel separation layer is configured to penetrate the electromagnetic wave absorption layer.

[0207] (7) The electromagnetic wave detection device according to any one of (1) to (6), wherein a shielding electrode is further provided between the second electrodes on the second main surface.

[0208] (8) The electromagnetic wave detection device according to any one of (1) to (7), wherein the low-dimensional electronic material comprises a material in which the movement of electrons within is confined to a region of less than two dimensions.

[0209] (9) The electromagnetic wave detection device according to (8), wherein the low-dimensional electronic material includes at least one or more of carbon nanotubes or graphene.

[0210] (10) The electromagnetic wave detection device according to any one of (1) to (9), wherein,

[0211] An insulating layer is also provided on the electromagnetic wave absorbing layer and the first electrode.

[0212] The insulating layer has at least one or more of the following: a lower thermal conductivity than the electromagnetic wave absorbing layer or a lower electromagnetic wave absorption rate than the electromagnetic wave absorbing layer.

[0213] (11) The electromagnetic wave detection device according to any one of (1) to (10), wherein a buffer layer is further provided between the electromagnetic wave absorbing layer and the second electrode.

[0214] (12) The electromagnetic wave detection device according to (11), wherein, when the low-dimensional electronic material is a p-type compound, the buffer layer comprises a buffer material with a lower electron affinity than the low-dimensional electronic material.

[0215] (13) The electromagnetic wave detection device according to (11), wherein, when the low-dimensional electronic material is an n-type compound, the buffer layer contains a buffer material with an ionization potential greater than that of the low-dimensional electronic material.

[0216] (14) The electromagnetic wave detection device according to any one of (1) to (13), wherein an insulating part including a gap is further provided between the second electrode and the readout circuit.

[0217] (15) The electromagnetic wave detection device according to any one of (1) to (14), wherein the electromagnetic wave absorbed by the electromagnetic wave absorption layer has a frequency of 100 GHz or more and 75 THz or less.

[0218] (16) An electromagnetic wave detection system, comprising:

[0219] Electromagnetic wave detection device; and

[0220] The shutter controls the incidence of electromagnetic waves onto the electromagnetic wave detection device, wherein...

[0221] The electromagnetic wave detection device includes:

[0222] Electromagnetic wave absorbing layer, which contains low-dimensional electronic materials that absorb electromagnetic waves;

[0223] The first electrode is disposed on the first main surface of the electromagnetic wave absorbing layer;

[0224] The second electrode is disposed on the second main surface of the electromagnetic wave absorbing layer opposite to the first main surface; and

[0225] The readout circuit reads from the second electrode the signal generated by the thermoelectric conversion through the heat generated by the electromagnetic wave absorbing layer that absorbs the electromagnetic wave.

[0226] (17) An electromagnetic wave detection method, comprising:

[0227] Electromagnetic waves are absorbed by low-dimensional electronic materials contained in an electromagnetic wave absorbing layer sandwiched between the first and second electrodes on their opposing main surfaces.

[0228] Thermoelectric conversion is performed on the heat generated by the electromagnetic wave absorbing layer by absorbing electromagnetic waves; and

[0229] The signal generated by the thermoelectric conversion is read from the second electrode.

[0230] This application claims the benefit of Japanese priority patent application No. 2019-186911, filed with the Japan Patent Office on October 10, 2019, the entire contents of which are incorporated herein by reference.

[0231] Those skilled in the art should understand that, within the scope of protection of the appended claims or their equivalents, various modifications, combinations, sub-combinations and alterations can be made according to design requirements and other factors.

Claims

1. An electromagnetic wave detection device, comprising: Electromagnetic wave absorbing layer, which contains low-dimensional electronic materials that absorb electromagnetic waves; The first electrode is disposed on the first main surface of the electromagnetic wave absorbing layer; The second electrode is disposed on the second main surface of the electromagnetic wave absorbing layer opposite to the first main surface; and The readout circuit reads from the second electrode the signal generated by the thermoelectric conversion through the heat generated by the electromagnetic wave absorbing layer that absorbs the electromagnetic waves. in, The first electrode is configured as a lattice-shaped single common electrode covering the entire first main surface. The first electrode has a plurality of openings arranged in a two-dimensional pattern, each of the plurality of openings constituting a pixel for detecting electromagnetic waves incident from the first main surface side, and The second electrode is configured to be separated from each pixel in the region of the second main surface corresponding to the plurality of openings. A buffer layer is also provided between the electromagnetic wave absorbing layer and the second electrode. When the low-dimensional electronic material is a p-type compound, the energy level of the buffer layer is set to be shallower than that of the electromagnetic wave absorbing layer, and the buffer layer contains a buffer material with a lower electron affinity than the low-dimensional electronic material. When the low-dimensional electronic material is an n-type compound, the energy level of the buffer layer is set to be deeper than that of the electromagnetic wave absorbing layer, and the buffer layer contains a buffer material with an ionization potential greater than that of the low-dimensional electronic material.

2. The electromagnetic wave detection device according to claim 1, wherein, A pixel separation layer is also provided to separate the electromagnetic wave absorption layer for each region where the plurality of openings are provided.

3. The electromagnetic wave detection device according to claim 2, wherein, The pixel separation layer is configured to penetrate the electromagnetic wave absorption layer.

4. The electromagnetic wave detection device according to claim 1, wherein, A shielding electrode is also provided between the second electrodes on the second main surface.

5. The electromagnetic wave detection device according to claim 1, wherein, The low-dimensional electronic material includes materials in which the movement of electrons within is confined to a region of less than two dimensions.

6. The electromagnetic wave detection device according to claim 5, wherein, The low-dimensional electronic material includes at least one or more of carbon nanotubes or graphene.

7. The electromagnetic wave detection device according to claim 1, wherein, An insulating layer is also provided on the electromagnetic wave absorbing layer and the first electrode. The insulating layer has at least one or more of the following: a lower thermal conductivity than the electromagnetic wave absorbing layer or a lower electromagnetic wave absorption rate than the electromagnetic wave absorbing layer.

8. The electromagnetic wave detection device according to claim 1, wherein, An insulating portion, including a gap, is also provided between the second electrode and the readout circuit.

9. The electromagnetic wave detection device according to claim 1, wherein, The electromagnetic waves absorbed by the electromagnetic wave absorbing layer have frequencies above 100 GHz and below 75 THz.

10. An electromagnetic wave detection system, comprising: Electromagnetic wave detection device according to any one of claims 1 to 9; and The shutter controls the incidence of electromagnetic waves on the electromagnetic wave detection device.

11. An electromagnetic wave detection method, comprising: Electromagnetic waves are absorbed by low-dimensional electronic materials contained in an electromagnetic wave absorbing layer sandwiched between a first electrode and a second electrode on a first and a second main surface that are opposite to each other. Thermoelectric conversion is performed on the heat generated by the electromagnetic wave absorbing layer by absorbing electromagnetic waves; and The signal generated by the thermoelectric conversion is read from the second electrode. in, The first electrode is configured as a lattice-shaped single common electrode covering the entire first main surface. The first electrode has a plurality of openings arranged in a two-dimensional pattern, each of the plurality of openings constituting a pixel for detecting electromagnetic waves incident from the first main surface side, and The second electrode is configured to be separated from each other in the region of the second main surface corresponding to the plurality of openings. A buffer layer is also provided between the electromagnetic wave absorbing layer and the second electrode. When the low-dimensional electronic material is a p-type compound, the energy level of the buffer layer is set to be shallower than that of the electromagnetic wave absorbing layer, and the buffer layer contains a buffer material with a lower electron affinity than the low-dimensional electronic material. When the low-dimensional electronic material is an n-type compound, the energy level of the buffer layer is set to be deeper than that of the electromagnetic wave absorbing layer, and the buffer layer contains a buffer material with an ionization potential greater than that of the low-dimensional electronic material.

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