Terahertz device

Abstract

A terahertz device (10) comprises: a substrate (20) including a substrate surface (21); a conductive layer (40) provided on the substrate surface (21); an annular slot (40A) provided in the conductive layer (40); and a first active element (60) and a second active element (70) which are disposed in the slot (40A) and which oscillate or detect electromagnetic waves. The conductive layer (40) includes a first electrode (41) disposed inside the slot (40A) in plan view and a second electrode (42) which is disposed outside the slot (40A) in plan view and which surrounds the first electrode (41) with the slot (40A) therebetween. If a first reference line (LA1) is defined as a line passing through the first active element (60) and the center (41C) of the first electrode (41) in plan view, the second active element (70) is disposed at an asymmetric position, which is a position different from a position on the first reference line (LA1) in the slot (40A).

Description

Terahertz device

[0001] This disclosure relates to a terahertz device.

[0002] In recent years, the miniaturization of electronic devices such as transistors has progressed, and as electronic devices have become nanoscale, phenomena known as quantum effects have begun to be observed. Development is underway to realize ultrafast devices and new functional devices that utilize these quantum effects.

[0003] In such an environment, as shown in Patent Document 1, for example, attempts are being made to use electromagnetic waves in a frequency range called the terahertz band, where the frequency is between 0.1 THz and 10 THz, for high-capacity communication, information processing, imaging, and measurement. Electromagnetic waves in this frequency range possess the characteristics of both light and radio waves, and if devices operating in this frequency range are realized, they can be used for many applications, including imaging, high-capacity communication, and information processing as mentioned above, as well as measurements in various fields such as physical property analysis, astronomy, and biology.

[0004] Japanese Patent Publication No. 2020-115500

[0005] [Overview] Terahertz devices are used as light sources that emit electromagnetic waves in the terahertz frequency band, and as detectors that detect electromagnetic waves in the terahertz frequency band. In such terahertz devices, higher output power and improved resolution are desired. Therefore, adjustment of the impedance in the antenna is required.

[0006] A terahertz apparatus according to one aspect of the present disclosure comprises a substrate including a substrate surface, a conductive layer provided on the substrate surface, an annular slot provided in the conductive layer, and a first active element and a second active element disposed in the slot for oscillating or detecting electromagnetic waves, wherein the conductive layer includes a first electrode disposed inside the slot in a plan view viewed from a direction perpendicular to the substrate surface, and a second electrode disposed outside the slot in the plan view, surrounding the first electrode through the slot, and in the plan view, if a straight line passing through the center of the first active element and the center of the first electrode is defined as a first reference line, the second active element is disposed in an asymmetric position within the slot that is different from its position on the first reference line.

[0007] Figure 1 is a schematic perspective view of an exemplary terahertz device according to the first embodiment. Figure 2 is a schematic plan view of the terahertz device of Figure 1. Figure 3 is a schematic cross-sectional view of the terahertz device cut along the line F3-F3 in Figure 2. Figure 4 is a schematic plan view showing some of the components of the terahertz device of Figure 1. Figure 5 is a schematic plan view showing the first active element and its surroundings in the terahertz device of Figure 1. Figure 6 is a schematic plan view showing the second active element and its surroundings in the terahertz device of Figure 1. Figure 7 is a schematic cross-sectional view showing the first active element of Figure 5, the second active element of Figure 6, and their surroundings. Figure 8 is an enlarged schematic plan view of the second resistive element and its surroundings in the terahertz device of Figure 1. Figure 9 is an enlarged schematic cross-sectional view of the second resistive element and its surroundings in Figure 8. Figure 10 is a schematic plan view showing some of the components of the terahertz device of Figure 1. Figure 11 is a schematic plan view showing some of the components of a comparative example terahertz device. Figure 12 is a graph showing the relationship between the area of ​​each active element of the terahertz device and the frequency of the electromagnetic waves emitted by the terahertz device. Figure 13 is a graph showing the relationship between the area of ​​each active element of the terahertz device and the output power of the terahertz device. Figure 14 is a graph showing the relationship between the frequency of the electromagnetic waves emitted by the terahertz device and the output power of the terahertz device. Figure 15 is a schematic plan view showing some of the components of the terahertz device of the second embodiment. Figure 16 is a graph showing the relationship between the second width of the second slot portion in the terahertz device of Figure 15 and the output power of the terahertz device. Figure 17 is a schematic plan view showing some of the components of the modified terahertz device. Figure 18 is a schematic plan view showing some of the components of the modified terahertz device. Figure 19 is a schematic plan view showing some of the components of the modified terahertz device. Figure 20 is a schematic plan view showing some of the components of the modified terahertz device. Figure 21 is a schematic plan view showing some of the components of the modified terahertz device. Figure 22 is a schematic plan view showing some of the components of the modified terahertz device. Figure 23 is a schematic plan view showing some of the components of the modified terahertz device. Figure 24 is a schematic plan view showing some of the components of the modified terahertz device. Figure 25 is a graph showing the relationship between the frequency of the electromagnetic waves emitted by the modified terahertz devices in Figures 22 to 24 and the output power of the terahertz device.FIG. 26 is a schematic plan view showing some components of a terahertz device of a modified example. FIG. 27 is a schematic plan view showing some components of a terahertz device of a modified example. FIG. 28 is a schematic plan view showing some components of a terahertz device of a modified example. FIG. 29 is a schematic plan view showing some components of a terahertz device of a modified example. FIG. 30 is a schematic plan view showing some components of a terahertz device of a modified example.

[0008] [Detailed Description] Hereinafter, some embodiments of the terahertz device of the present disclosure will be described with reference to the accompanying drawings. Note that, for the sake of simplicity and clarity of the description, the components shown in the drawings are not necessarily drawn at a certain scale. Also, for ease of understanding, in sectional views, the hatching lines may be omitted. The accompanying drawings are merely illustrative of the embodiments of the present disclosure and should not be regarded as limiting the present disclosure.

[0009] The following detailed description includes devices, systems, and methods that embody exemplary embodiments of the present disclosure. This detailed description is for illustrative purposes only and is not intended to limit the embodiments of the present disclosure or the application and use of such embodiments.

[0010] The terms "first", "second", "third", etc. in the present disclosure are merely used for labeling and are not necessarily intended to assign an order to their objects. The expression "at least one" used in the present disclosure means "one or more" of the desired options. As an example, the expression "at least one" used in the present disclosure means "only one option" or "both of the two options" if the number of options is two. As another example, the expression "at least one" used in the present disclosure means "only one option" or "any combination of two or more options" if the number of options is three or more.

[0011] The phrase "the dimension (width, length) of A is equal to the dimension (width, length) of B" or "the dimension (width, length) of A and the dimension (width, length) of B are equal to each other" used in the present disclosure also includes a relationship in which the difference between the dimension (width, length) of A and the dimension (width, length) of B is within 10% of the dimension (width, length) of A, for example.

[0012] <First Embodiment> [Overall Configuration of Terahertz Device]Referring to FIGS. 1 to 4, the overall configuration of the terahertz device 10 according to the first embodiment will be described. FIG. 1 schematically shows the perspective structure of the terahertz device 10 according to the first embodiment. FIG. 2 schematically shows the planar structure of the terahertz device 10 in FIG. 1. FIG. 3 schematically shows the cross-sectional structure of the terahertz device 10 cut along the line F3-F3 in FIG. 2. FIG. 4 schematically shows the planar structure of the terahertz device 10 with some of its components omitted in FIG. 2.

[0013] As shown in FIG. 1, the terahertz device 10 includes a substrate 20. The substrate 20 is in the shape of a flat plate with the Z direction as the thickness direction. It can also be said that the substrate 20 is in the shape of a rectangular parallelepiped. Here, among the directions orthogonal to the Z direction, two mutually orthogonal directions are defined as the "X direction" and the "Y direction". Also, viewing the terahertz device 10 from the Z direction is referred to as "planar view". As shown in FIG. 2, the substrate 20 is square in planar view. Note that the shape of the substrate 20 in planar view can be arbitrarily changed.

[0014] As shown in FIGS. 2 and 3, the substrate 20 includes a substrate front surface 21, a substrate back surface 22 on the side opposite to the substrate front surface 21, and substrate side surfaces 23 to 26 connecting the substrate front surface 21 and the substrate back surface 22. The substrate front surface 21 and the substrate back surface 22 face opposite sides in the Z direction. For this reason, "planar view" can also mean viewing from a direction perpendicular to the substrate front surface 21. Also, "perpendicular" includes not only the case of strict perpendicularity but also the case of being generally perpendicular within the range where the effects of this embodiment are achieved. The substrate side surfaces 23 and the substrate side surfaces 24 constitute both end faces of the substrate 20 in the Y direction. The substrate side surfaces 25 and the substrate side surfaces 26 constitute both end faces of the substrate 20 in the X direction.

[0015] As shown in FIG. 2, the substrate 20 has a length in the X direction and a length in the Y direction. The length in the X direction can be 1 mm or less. In one example, the length in the X direction can be 500 μm. The length in the Y direction can be 1 mm or less. In one example, the length in the Y direction can be 500 μm.

[0016] As shown in Figure 3, the substrate 20 includes a semiconductor substrate 31 and an insulating layer 32 provided on the semiconductor substrate 31. The semiconductor substrate 31 is a flat plate with the Z direction as the thickness direction. As shown in Figure 2, the semiconductor substrate 31 is rectangular in plan view. In one example, the semiconductor substrate 31 is square in plan view. Note that the shape of the semiconductor substrate 31 in plan view can be arbitrarily changed and may be circular, elliptical, polygonal, etc.

[0017] As shown in Figure 3, the semiconductor substrate 31 is composed of at least one semiconductor material selected from the group consisting of InP (indium phosphide), GaAs (gallium arsenide), AlGaAs (aluminum gallium arsenide), InGaAs (indium gallium arsenide), InGaAsP (indium gallium arsenide phosphide), and single-crystal AlN (aluminum nitride). In one example, the semiconductor substrate 31 is composed of a material containing InP. The semiconductor substrate 31 includes a surface 311 and a back surface 312 opposite to the surface 311. The semiconductor substrate 31 includes sides that constitute a portion of the Z-direction of the substrate sides 23 to 26 of the substrate 20.

[0018] The insulating layer 32 covers the surface 311 of the semiconductor substrate 31. In one example, the insulating layer 32 may be provided over the entire surface 311 of the semiconductor substrate 31. The insulating layer 32 is made of an insulating material. For example, the insulating layer 32 is made of SiO ２ It may be made of silicon oxide. The insulating layer 32 may be made of, for example, SiN (silicon nitride).

[0019] The insulating layer 32 includes an insulating surface 321 and an insulating back surface 322 opposite to the insulating surface 321. The insulating surface 321 constitutes the substrate surface 21 of the substrate 20. The insulating back surface 322 is in contact with the surface 311 of the semiconductor substrate 31. Note that another component, such as an insulating layer, may be interposed between the surface 311 of the semiconductor substrate 31 and the insulating layer 32. The insulating layer 32 includes sides that constitute a portion of the substrate sides 23-26 (see Figure 2) of the substrate 20 in the Z direction.

[0020] The terahertz apparatus 10 includes a conductive layer 40 provided on the substrate surface 21 of the substrate 20. The conductive layer 40 is provided on a portion of the substrate surface 21. The conductive layer 40 is composed of at least one metallic material selected from the group consisting of Au (gold), Ag (silver), Al (aluminum), Cu (copper), Ti (titanium), TiN (titanium nitride), and Pt (platinum). It can also be said that the conductive layer 40 contains at least one of Au, Ag, Al, Cu, Ti, and Pt. In one example, the conductive layer 40 is composed of a material containing Au. The conductive layer 40 is formed, for example, by sputtering. The conductive layer 40 may be composed of a laminated structure of multiple metal layers. In one example, the thickness of the conductive layer 40 is 0.3 μm or more.

[0021] As shown in Figure 4, the terahertz device 10 includes an annular slot 40A provided in the conductive layer 40. In one example, the slot 40A is annular in plan view. In the first embodiment, the width WS of the slot 40A is constant over substantially the entire circumferential direction of the slot 40A. Here, the width WS of the slot 40A can be defined by the distance between the inner edge 40AA and the outer edge 40AB of the slot 40A in the radial direction with respect to the center of the annular slot 40A.

[0022] The conductive layer 40 includes a first electrode 41 partitioned by a slot 40A, and a second electrode 42 surrounding the first electrode 41 via the slot 40A in a plan view. Therefore, the first electrode 41 can be said to be located inside the slot 40A. The outer edge of the first electrode 41 can be said to constitute the inner edge 40AA of the slot 40A. The second electrode 42 can be said to be located outside the slot 40A. The inner edge of the second electrode 42 can be said to constitute the outer edge 40AB of the slot 40A. In this way, the end faces of the conductive layer 40 (first electrode 41, second electrode 42) facing the annular slot 40A constitute the ring slot antenna 40R.

[0023] As used in this description, the term “ring-shaped” refers to any structure that forms a loop, i.e., a continuous shape without ends, as well as structures that, as a whole, form a loop shape, even if they have a gap such as a C-shape. “Ring-shaped” shapes include, but are not limited to, circles, ellipses, and polygons with pointed or rounded corners.

[0024] The first electrode 41 is positioned at the center of the substrate 20 in a plan view. The first electrode 41 is circular in a plan view. The diameter of the circular first electrode 41 may be set according to the desired oscillation frequency of the terahertz device 10.

[0025] The external shape of the second electrode 42 may be a rectangle in plan view. In plan view, the second electrode 42 includes a first side 421 and a second side 422 that extend parallel to each other, and a third side 423 and a fourth side 424 that are perpendicular to the first side 421 and the second side 422. In one example, the second electrode 42 may be a rectangle in which the lengths of the first side 421 and the second side 422 are greater than the lengths of the third side 423 and the fourth side 424. In one example, the second electrode 42 may be arranged in plan view such that both the first side 421 and the second side 422 extend in the X direction, and both the third side 423 and the fourth side 424 extend in the Y direction. In another example, the second electrode 42 may be a square in which the lengths of the first side 421 and the second side 422 and the lengths of the third side 423 and the fourth side 424 are equal. In other words, the external shape of the second electrode 42 may be a square in plan view. In another example, the second electrode 42 may be a rectangle in which the lengths of the third side 423 and the fourth side 424 are greater than the lengths of the first side 421 and the second side 422.

[0026] The terahertz device 10 includes a first active element 60 and a second active element 70 provided in a slot 40A. The first active element 60 and the second active element 70 are positioned between a first electrode 41 and a second electrode 42.

[0027] The first active element 60 and the second active element 70 are elements that convert electromagnetic waves into electrical energy. Electromagnetic waves include the concepts of light, radio waves, or both. The first active element 60 and the second active element 70 are elements that emit electromagnetic waves (terahertz waves) in a predetermined frequency range, for example, the terahertz band. In this case, the first active element 60 and the second active element 70 can also be said to be terahertz elements that emit terahertz waves. Alternatively, for example, the first active element 60 and the second active element 70 are elements that detect terahertz waves, which are electromagnetic waves in a predetermined frequency range, for example, the terahertz band. In this case, the first active element 60 and the second active element 70 can be said to be terahertz elements that receive terahertz waves. Here, the frequency range of terahertz waves is, for example, 0.1 THz to 10 THz. Thus, the first active element 60 and the second active element 70 can be said to be elements that oscillate or detect electromagnetic waves.

[0028] The first active element 60 and the second active element 70 are configured to convert supplied electrical energy into electromagnetic waves by oscillation caused by the supplied electrical energy. As a result, the first active element 60 and the second active element 70 oscillate electromagnetic waves in a desired frequency range. Furthermore, the first active element 60 and the second active element 70 are configured to receive electromagnetic waves and convert those electromagnetic waves into electrical energy. As a result, the first active element 60 and the second active element 70 detect electromagnetic waves in a desired frequency range.

[0029] In one example, the first active element 60 and the second active element 70 may be resonant tunneling diodes (RTDs). In another example, the first active element 60 and the second active element 70 may be diodes or transistors other than RTDs. Other active elements may include, for example, Tunnel injection Transit Time (TUNNETT) diodes, Impact Ionization Avalanche Transit Time (IMPATT) diodes, GaAs field effect transistors (FETs), GaN FETs, high electron mobility transistors (HEMTs), heterojunction bipolar transistors (HBTs), CMOS (Complementary Metal-Oxide-Semiconductor) FETs, or Schottky barrier diodes (SBDs).

[0030] The first active element 60 and the second active element 70 are rectangular in plan view. In one example, the first active element 60 and the second active element 70 may be rectangular in plan view, having a long side and a short side. The first active element 60 and the second active element 70 may be arranged such that their long sides extend in a direction perpendicular to the circumferential direction of the slot 40A in plan view. In the first embodiment, the dimensions of the long sides of the first active element 60 and the second active element 70 are smaller than the width WS of the slot 40A. Note that the shape of the first active element 60 and the second active element 70 in plan view is not limited to a rectangular shape, but may be circular, elliptical, or polygonal.

[0031] Both the first active element 60 and the second active element 70 are connected between the first electrode 41 and the second electrode 42. Both the first active element 60 and the second active element 70 are connected between the first electrode 41 and the second electrode 42 in parallel.

[0032] As shown in Figures 2 and 4, the terahertz device 10 may include a first resistive element 81 and a second resistive element 82. Both the first resistive element 81 and the second resistive element 82 may be located outside the slot 40A. In one example, both the first resistive element 81 and the second resistive element 82 may be positioned to overlap with the second electrode 42 in a plan view. The first resistive element 81 and the second resistive element 82 are electrically connected in parallel to the first active element 60 and the second active element 70. Both the first resistive element 81 and the second resistive element 82 are configured to suppress parasitic oscillations. This allows the oscillation to be stabilized in the terahertz device 10. The detailed arrangement of the first active element 60, the second active element 70, the first resistive element 81, and the second resistive element 82 will be described later with reference to Figure 10.

[0033] [Detailed Configuration of the First and Second Active Elements] The detailed configurations of the first active element 60 and the second active element 70 will be described with reference to Figures 5 to 7. Figure 5 is a magnified planar structure of a part of the terahertz device 10 in Figure 2, schematically showing the arrangement of the first active element 60. Figure 6 is a magnified planar structure of another part of the terahertz device 10 in Figure 2, schematically showing the arrangement of the second active element 70. Figure 7 schematically shows the cross-sectional structure of the first active element 60, the second active element 70, and their surroundings.

[0034] As shown in Figure 5, the first active element 60 is connected between the second electrode 42 and the first electrode 41. More specifically, the conductive layer 40 includes a connecting portion 441 extending from the second electrode 42 toward the first electrode 41. The conductive layer 40 also includes a connecting portion 431 extending from the first electrode 41 toward the second electrode 42. The first active element 60 is connected between the second electrode 42 and the first electrode 41 by the connecting portions 441 and 431.

[0035] An example of a configuration for realizing the first active element 60 will be described. As shown in Figures 5 and 7, the first active element 60 is provided between the first electrode 41 and the semiconductor substrate 31 in the Z direction.

[0036] As shown in Figure 7, a semiconductor layer 61a is provided on the surface 311 of the semiconductor substrate 31. In one example, the semiconductor layer 61a is rectangular in shape when viewed from above. The semiconductor layer 61a is made of, for example, GaInAs. The semiconductor layer 61a is highly doped with n-type impurities. A GaInAs layer 62a is stacked on top of the semiconductor layer 61a. The GaInAs layer 62a is doped with n-type impurities. The n-type impurity concentration of the GaInAs layer 62a is lower than that of the semiconductor layer 61a. A GaInAs layer 63a is stacked on top of the GaInAs layer 62a. The GaInAs layer 63a is not doped with impurities.

[0037] An AlAs layer 64a is stacked on top of a GaInAs layer 63a. An InGaAs layer 65 is stacked on top of the AlAs layer 64a. The InGaAs layer 65 is not doped with impurities. An AlAs layer 64b is stacked on top of the InGaAs layer 65. These AlAs layers 64a, 65, and 64b constitute a resonant tunnel.

[0038] An undoped GaInAs layer 63b is stacked on top of the AlAs layer 64b. A GaInAs layer 62b doped with n-type impurities is stacked on top of the GaInAs layer 63b. A GaInAs layer 61b highly doped with n-type impurities is stacked on top of the GaInAs layer 62b. The n-type impurity concentration in the GaInAs layer 61b is higher than that in the GaInAs layer 62b.

[0039] The specific configuration of the first active element 60 can be arbitrarily changed as long as it is capable of generating (or detecting, or both) electromagnetic waves. In other words, the first active element 60 only needs to be configured to perform at least one of the following: oscillation and detection of electromagnetic waves in the terahertz band.

[0040] The connection portion 441 extending from the second electrode 42 extends toward the semiconductor layer 61a and is electrically connected to the semiconductor layer 61a. The connection portion 431 extending from the first electrode 41 is in contact with the upper surface of the GaInAs layer 61b and is electrically connected to the GaInAs layer 61b. In this way, the first active element 60 is connected between the second electrode 42 and the first electrode 41.

[0041] As shown in Figure 5, the second active element 70 is connected between the first electrode 41 and the second electrode 42. More specifically, the conductive layer 40 includes a connecting portion 432 extending from the first electrode 41 toward the second electrode 42. The conductive layer 40 also includes a connecting portion 442 extending from the second electrode 42 toward the first electrode 41. The second active element 70 is connected between the first electrode 41 and the second electrode 42 by the connecting portions 432 and 442.

[0042] An example of a configuration for realizing the second active element 70 will be described. As shown in Figures 6 and 7, the second active element 70 is provided between the first electrode 41 and the semiconductor substrate 31 in the Z direction.

[0043] As shown in Figure 7, a semiconductor layer 71a is provided on the surface 311 of the semiconductor substrate 31. In one example, the semiconductor layer 71a is rectangular in shape when viewed from above. The semiconductor layer 71a is made of, for example, GaInAs. The semiconductor layer 71a is highly doped with n-type impurities. A GaInAs layer 72a is stacked on top of the semiconductor layer 71a. The GaInAs layer 72a is doped with n-type impurities. The n-type impurity concentration of the GaInAs layer 72a is lower than that of the semiconductor layer 71a. A GaInAs layer 73a is stacked on top of the GaInAs layer 72a. The GaInAs layer 73a is not doped with impurities.

[0044] An AlAs layer 74a is stacked on top of a GaInAs layer 73a. An InGaAs layer 75 is stacked on top of the AlAs layer 74a. The InGaAs layer 75 is not doped with impurities. An AlAs layer 74b is stacked on top of the InGaAs layer 75. These AlAs layers 74a, 75, and 74b constitute a resonant tunnel.

[0045] An undoped GaInAs layer 73b is stacked on top of the AlAs layer 74b. A GaInAs layer 72b doped with n-type impurities is stacked on top of the GaInAs layer 73b. A GaInAs layer 71b highly doped with n-type impurities is stacked on top of the GaInAs layer 72b. The n-type impurity concentration in the GaInAs layer 71b is higher than that in the GaInAs layer 72b.

[0046] The specific configuration of the second active element 70 can be arbitrarily changed as long as it is capable of generating (or detecting, or both) electromagnetic waves. In other words, the second active element 70 only needs to be configured to perform at least one of the following: oscillation and detection of electromagnetic waves in the terahertz band.

[0047] The connection portion 432 extending from the first electrode 41 is in contact with the upper surface of the GaInAs layer 71b and is electrically connected to the GaInAs layer 71b. The connection portion 442 extending from the second electrode 42 extends toward the semiconductor layer 71a and is electrically connected to the semiconductor layer 71a. In this way, the second active element 70 is connected between the first electrode 41 and the second electrode 42.

[0048] [Detailed Configuration of Resistor Elements] The detailed configurations of the first resistor element 81 and the second resistor element 82 will be described with reference to Figures 1, 4, 8, and 9. Figure 8 is a planar structure of a part of the terahertz device 10 of Figure 2, schematically showing the arrangement of the first resistor element 81. Figure 9 schematically shows the cross-sectional structure of the first resistor element 81 and its surroundings in Figure 8.

[0049] As shown in Figure 9, the second resistive element 82 is provided between the semiconductor substrate 31 and the second electrode 42. The second resistive element 82 is provided on the surface 311 of the semiconductor substrate 31. In one example, the second resistive element 82 has a rectangular shape in plan view. The second resistive element 82 is composed of a semiconductor layer doped with a high concentration of n-type impurities. In one example, the semiconductor layer may be GaInAs.

[0050] The second resistive element 82 includes a first end 821 and a second end 822 opposite to the first end 821. The first end 821 is electrically connected to the second electrode 42 by a via 83B provided on the second resistive element 82. The via 83B is made of at least one metallic material selected from the group Au, Ag, Al, Cu, Ti, TiN, and Pt. It can also be said that the via 83B includes at least one of Au, Ag, Al, Cu, Ti, and Pt. In one example, the via 83B may be made of a material containing Au.

[0051] A lower wiring 84B is electrically connected to the second end 822 of the second resistive element 82. The lower wiring 84B is located within the insulating layer 32 in the Z direction. It can be said that the lower wiring 84B is located between the insulating surface 321 and the insulating back surface 322 in the Z direction. In one example, the insulating layer 32 may include a first insulating film provided on the semiconductor substrate 31 and a second insulating film provided on the first insulating film. The first insulating film may be made of the same thickness as, for example, the second resistive element 82. The lower wiring 84B may be provided on the first insulating film. The insulating layer 32 may also include three or more insulating films. The lower wiring 84B is made of at least one metallic material selected from the group Au, Ag, Al, Cu, Ti, TiN, and Pt. It can also be said that the lower wiring 84B includes at least one of Au, Ag, Al, Cu, Ti, and Pt. In one example, the lower wiring 84B may be made of a material including Au.

[0052] As shown in Figures 4 and 8, the lower wiring 84B extends toward the first electrode 41. It can be said that the lower wiring 84B extends so as to intersect with the slot 40A between the second electrode 42 and the first electrode 41. The lower wiring 84B is electrically connected to the first electrode 41 by via 85B. The via 85B is made of at least one metallic material selected from the group Au, Ag, Al, Cu, Ti, TiN, and Pt. It can also be said that the via 85B contains at least one of Au, Ag, Al, Cu, Ti, and Pt. In one example, the via 85B may be made of a material containing Au.

[0053] As shown in Figures 1 and 4, the first resistive element 81 is electrically connected to the first electrode 41 and the second electrode 42, similar to the second resistive element 82. Although not shown, the first resistive element 81 is provided on the surface 311 of the semiconductor substrate 31, similar to the second resistive element 82. In one example, the first resistive element 81 has a rectangular shape in plan view. The first resistive element 81 is composed of a semiconductor layer doped with a high concentration of n-type impurities. In one example, the semiconductor layer may be GaInAs.

[0054] The first resistive element 81 includes a first end 811 and a second end 812 opposite to the first end 811. The first end 811 is electrically connected to the second electrode 42 by a via 83A provided on the first resistive element 81. The via 83A is made of at least one metallic material selected from the group Au, Ag, Al, Cu, Ti, TiN, and Pt. It can also be said that the via 83A includes at least one of Au, Ag, Al, Cu, Ti, and Pt. In one example, the via 83A may be made of a material containing Au.

[0055] A lower wiring 84A is electrically connected to the second end 812 of the first resistive element 81. The lower wiring 84A is located within the insulating layer 32 in the Z direction. It can be said that the lower wiring 84A is located between the insulating surface 321 and the insulating back surface 322 (both see Figure 9) in the Z direction. In one example, the first insulating film of the insulating layer 32 may be provided with the same thickness as, for example, the first resistive element 81. The lower wiring 84A may be provided on the first insulating film. The lower wiring 84A is made of at least one metallic material selected from the group Au, Ag, Al, Cu, Ti, TiN, and Pt. It can also be said that the lower wiring 84A includes at least one of Au, Ag, Al, Cu, Ti, and Pt. In one example, the lower wiring 84A may be made of a material including Au.

[0056] As shown in Figures 4 and 8, the lower wiring 84A extends toward the first electrode 41. In plan view, the lower wiring 84A can be said to extend so as to intersect with the slot 40A between the second electrode 42 and the first electrode 41. The lower wiring 84A is electrically connected to the first electrode 41 by via 85A. The via 85A is made of at least one metallic material selected from the group Au, Ag, Al, Cu, Ti, TiN, and Pt. It can also be said that the via 85A contains at least one of Au, Ag, Al, Cu, Ti, and Pt. In one example, the via 85A may be made of a material containing Au.

[0057] [Electrode Pads] As shown in Figures 1 and 2, the terahertz apparatus 10 includes a first electrode pad 51 and a second electrode pad 52 provided on the substrate surface 21 of the substrate 20. In one example, the first electrode pad 51 and the second electrode pad 52 are arranged along the substrate side surface 23 on the substrate surface 21 of the substrate 20. In the first embodiment, the first electrode pad 51 is located at a corner 21A formed by the substrate side surface 23 and the substrate side surface 26 on the substrate surface 21. The second electrode pad 52 is located at a corner 21B formed by the substrate side surface 23 and the substrate side surface 25 on the substrate surface 21. In this way, the first electrode pad 51 and the second electrode pad 52 are located at the edge of the substrate 20 in a plan view.

[0058] Furthermore, the terahertz device 10 includes a first connecting wire 53 that electrically connects the first electrode pad 51 and the first electrode 41, and a second connecting wire 54 that electrically connects the second electrode pad 52 and the second electrode 42.

[0059] The first connecting wiring 53 includes a first wiring 531, a second wiring 532, a lower wiring 533, and a via 534. The first wiring 531 extends in the X direction from the first electrode pad 51. The second wiring 532 extends in the Y direction from the tip of the first wiring 531. The via 534 is connected to the tip of the second wiring 532. The lower wiring 533 is connected to the second wiring 532 by the via 534 and is also electrically connected to the lower wiring 84A.

[0060] The second connecting wire 54 includes the first wire 541 and the second wire 542. The first wire 541 extends in the X direction from the second electrode pad 52. The second wire 542 extends in the Y direction from the tip of the first wire 541 and is electrically connected to the second electrode 42.

[0061] [Reflective Layer] As shown in Figure 3, the terahertz device 10 includes a reflective layer 33 provided on the back surface 312 of the semiconductor substrate 31. The reflective layer 33 is in contact with the back surface 312 of the semiconductor substrate 31. The reflective layer 33 is configured to reflect electromagnetic waves. The reflective layer 33 includes a reflective surface 331 and a reflective back surface 332 on the opposite side of the reflective surface 331. The reflective surface 331 faces the same side as the substrate surface 21. The reflective back surface 332 constitutes the substrate back surface 22. The reflective layer 33 has a thickness that allows it to reflect electromagnetic waves generated or detected by the first active element 60 and the second active element 70. In one example, the reflective layer 33 may be arranged to overlap with the slot 40A (see Figure 2) in a plan view. In one example, the reflective layer 33 may be provided over the entire back surface 312 of the semiconductor substrate 31.

[0062] The reflective layer 33 is composed of a metal layer provided on the back surface 312 of the semiconductor substrate 31. The reflective layer 33 is composed of at least one metallic material selected from the group Au, Ag, Al, Cu, Ti, TiN, and Pt. It can also be said that the reflective layer 33 contains at least one of Au, Ag, Al, Cu, Ti, and Pt. In one example, the reflective layer 33 may be composed of a material containing Au. The reflective layer 33 may be composed of the same material as the conductive layer 40. The reflective layer 33 is formed, for example, by sputtering. The reflective layer 33 may be composed of a laminated structure of multiple metal layers.

[0063] [Arrangement of Active and Resistive Elements] Referring to Figure 10, the arrangement of the first active element 60, the second active element 70, the first resistive element 81, and the second resistive element 82 will be described. In the following description, "circumferential direction of slot 40A" refers to the direction in which slot 40A extends in a plan view. In the first embodiment, since slot 40A is annular, the circumferential direction of slot 40A refers to the direction along the annular shape centered on the center 41C of the first electrode 41 (center of slot 40A).

[0064] In Figure 10, for convenience, the first resistive element 81 and the second resistive element 82 are shown as being positioned across the width of the slot 40A, in order to easily understand the electrical connection points between them. Also, in Figure 10, the connection structure between the first active element 60 and the second active element 70 and the first electrode 41 and the second electrode 42 is shown in a simplified manner for easier understanding of the drawing.

[0065] As shown in Figure 10, the first active element 60 and the second active element 70 are arranged within the slot 40A as described above. The first active element 60 and the second active element 70 are positioned at locations different from those that are point-symmetric with respect to the center 41C of the first electrode 41 (the center of the slot 40A). In detail, if the line passing through the first active element 60 and the center 41C of the first electrode 41 is defined as the first reference line LA1 in a plan view, then the second active element 70 is positioned at an asymmetric location different from its position on the first reference line LA1 within the slot 40A (position PS shown in Figure 10). In other words, if the line passing through the second active element 70 and the center 41C of the first electrode 41 is defined as the second reference line LA2 in a plan view, then the angle A1 between the first reference line LA1 and the second reference line LA2 is less than 180°. Here, the first reference line LA1 is a straight line that passes through the center of the first active element 60 in the circumferential direction of the slot 40A. The second reference line LA2 is a straight line that passes through the center of the second active element 70 in the circumferential direction of the slot 40A.

[0066] In one example, in a plan view, the first auxiliary line LB1 is defined as a line passing through the center 41C of the first electrode 41 and perpendicular to the first reference line LA1. In this case, in a plan view, the second active element 70 may be positioned closer to the first active element 60 with respect to the first auxiliary line LB1 in the direction in which the first reference line LA1 extends. Specifically, the second active element 70 may be positioned within region R1 between the first auxiliary line LB1 and the first reference line LA1 in the circumferential direction of the slot 40A. Thus, it can be said that the first active element 60 and the second active element 70 are positioned closer to the first auxiliary line LB1 in the direction in which the first reference line LA1 extends. Here, region R1 is the circumferential region of the slot 40A where the angle between the first auxiliary line LB1 and the first reference line LA1 is 90°. Since the second active element 70 is located within this region R1, the angle A1 between the first reference line LA1 and the second reference line LA2 can be said to be less than 90°. In the first embodiment, the angle A1 between the first reference line LA1 and the second reference line LA2 is 20°.

[0067] Here, in the circumferential direction of slot 40A, the clockwise direction in a plan view is defined as the first circumferential direction W1, and the counterclockwise direction as the second circumferential direction W2. In this case, the region R1 shown in Figure 10 is the region of slot 40A in the first circumferential direction W1 from the first reference line LA1 to the first auxiliary line LB1.

[0068] From the perspective of the circumferential distance of slot 40A, the distance DA between the first active element 60 and the second active element 70 in the first circumferential direction W1 is smaller than the distance DB between the first active element 60 and the second active element 70 in the second circumferential direction W2. In the example shown in Figure 10, each of the distances DA and DB can be defined as the length of the line segment connecting the center of the first active element 60 and the center of the second active element 70 in the circumferential direction of slot 40A.

[0069] Furthermore, distances DA and DB may be defined by the distance between the sides of the first active element 60 and the second active element 70 in the circumferential direction of slot 40A. That is, distance DA may be defined by the distance in the first circumferential direction W1 from the side of the first active element 60 that is closer to the second active element 70 to the side of the second active element 70 that is closer to the first active element 60. Distance DB may be defined by the distance in the second circumferential direction W2 from the side of the first active element 60 that is further from the second active element 70 to the side of the second active element 70 that is further from the first active element 60.

[0070] In a plan view, the line connecting the center 41C of the first electrode 41, the first resistive element 81, and the second resistive element 82 is defined as the second auxiliary line LB2. In Figure 10, the second auxiliary line LB2 is formed as a line that passes through the center 41C of the first electrode 41 and lies along the Y direction in a plan view. In the first embodiment, the first resistive element 81 and the second resistive element 82 are arranged on both sides of the center 41C of the first electrode 41 along the second auxiliary line LB2. That is, the first resistive element 81 and the second resistive element 82 are arranged symmetrically with respect to the first electrode 41. More specifically, the first resistive element 81 and the second resistive element 82 are arranged in a point-symmetric relationship with respect to the center 41C of the first electrode 41. Here, the second auxiliary line LB2 is a line that passes through the center of the first resistive element 81 and the center of the second resistive element 82 shown in Figure 10 in a plan view.

[0071] The first resistive element 81 is positioned in the circumferential direction of slot 40A, overlapping with region R1. On the other hand, the second resistive element 82 is positioned in a different location from region R1 in the circumferential direction of slot 40A. Furthermore, the first active element 60 and the second active element 70 are positioned on both sides of the second auxiliary line LB2 in a plan view. In the example shown in Figure 10, the first active element 60 and the second active element 70 are dispersed on both sides of the second auxiliary line LB2 in the X direction in a plan view. The first active element 60 and the second active element 70 are positioned biased towards the first resistive element 81 in the circumferential direction of slot 40A. It can also be said that the first resistive element 81 is positioned between the first active element 60 and the second active element 70 in the circumferential direction of slot 40A. In other words, the first distance D1 between the first resistive element 81 and the first active element 60 in the circumferential direction of slot 40A is smaller than the second distance D2 between the second resistive element 82 and the first active element 60 in the circumferential direction of slot 40A.

[0072] Here, the first distance D1 can be defined by the length of the line segment connecting the center of the first resistive element 81 and the center of the first active element 60 in the circumferential direction of slot 40A. More specifically, the first distance D1 can be defined by the distance between the center of the first resistive element 81 and the center of the first active element 60 in the second circumferential direction W2 of slot 40A. In other words, the first distance D1 can also be said to be the shortest distance between the center of the first resistive element 81 and the center of the first active element 60 in the circumferential direction of slot 40A. Furthermore, the second distance D2 can be defined by the length of the line segment connecting the center of the second resistive element 82 and the center of the first active element 60 in the circumferential direction of slot 40A. More specifically, the second distance D2 can be defined by the distance between the center of the second resistive element 82 and the center of the first active element 60 in the first circumferential direction W1 of slot 40A. In other words, the second distance D2 can also be said to be the shortest distance between the second resistive element 82 and the first active element 60 in the circumferential direction of the slot 40A.

[0073] The first distance D1 may be defined as the distance between the side of the first resistive element 81 closer to the first active element 60 in the circumferential direction of the slot 40A and the side of the first active element 60 closer to the first resistive element 81. The second distance D2 may be defined as the distance between the side of the second resistive element 82 closer to the first active element 60 in the circumferential direction of the slot 40A and the side of the first active element 60 closer to the second resistive element 82.

[0074] If the first angle AR1 is the angle between the first resistive element 81 and the first active element 60 with respect to the center 41C of the first electrode 41, then the first angle AR1 may be less than 90°. If the second angle AR2 is the angle between the first resistive element 81 and the second active element 70 with respect to the center 41C of the first electrode 41, then the second angle AR2 may be less than 90°. In one example, both the first angle AR1 and the second angle AR2 may be less than 90°, and the first angle AR1 and the second angle AR2 may be equal to each other. Therefore, in a plan view, the first active element 60 and the second active element 70 are arranged in a symmetrical relationship with respect to the second auxiliary line LB2. In one example, both the first angle AR1 and the second angle AR2 may be less than 45°. In the example shown in Figure 10, both the first angle AR1 and the second angle AR2 are 10°.

[0075] Here, the first angle AR1 can be defined as the minimum angle between the straight line connecting the center 41C of the first electrode 41 and the first resistive element 81 (second auxiliary line LB2) and the straight line connecting the center 41C of the first electrode 41 and the first active element 60 (first reference line LA1). The second angle AR2 can be defined as the minimum angle between the straight line connecting the center 41C of the first electrode 41 and the second resistive element 82 (second auxiliary line LB2) and the straight line connecting the center 41C of the first electrode 41 and the second active element 70 (second reference line LA2).

[0076] In Figure 10, if we consider a coordinate plane where the center 41C of the first electrode 41 is the origin, the axis passing through the origin along the X direction is the X-axis, and the axis passing through the origin along the Y direction is the Y-axis, then the first active element 60 is located in the second quadrant, and the second active element 70 is located in the first quadrant. The first resistive element 81 is located so as to straddle the boundary (Y-axis) between the first and second quadrants, and the second resistive element 82 is located so as to straddle the boundary (Y-axis) between the third and fourth quadrants.

[0077] The first active element 60 is positioned in the circumferential direction of the slot 40A, away from both the X and Y axes in the second quadrant. In one example, the first active element 60 may be positioned in the circumferential direction of the slot 40A, closer to the Y axis than to the X axis in the second quadrant.

[0078] The second active element 70 is positioned in the circumferential direction of the slot 40A, away from both the X and Y axes in the first quadrant. In one example, the second active element 70 may be positioned in the circumferential direction of the slot 40A, closer to the Y axis than to the X axis in the first quadrant.

[0079] Depending on the arrangement of the first active element 60 and the second active element 70 as described above, the slot 40A includes a first slot portion 40AP from the first active element 60 to the second active element 70 in the first circumferential direction W1, and a second slot portion 40AQ from the first active element 60 to the second active element 70 in the second circumferential direction W2. The second auxiliary line LB2 is located in the first slot portion 40AP. The first auxiliary line LB1 is located in the second slot portion 40AQ. In the circumferential direction of the slot 40A, the length LP of the first slot portion 40AP is shorter than the length LQ of the second slot portion 40AQ. As described above, the ring slot antenna 40R is constructed by the conductive layer 40 including the annular slot 40A. Therefore, it can be said that the ring slot antenna 40R includes a first slot portion 40AP and a second slot portion 40AQ with different lengths LP and LQ. Furthermore, it can be said that the lengths LP and LQ are changed according to the arrangement positions of the first active element 60 and the second active element 70.

[0080] The first resistive element 81 is located in the first slot portion 40AP, and the second resistive element 82 is located in the second slot portion 40AQ. In the example shown in Figure 10, the first resistive element 81 is located in the center of the first slot portion 40AP in the circumferential direction of slot 40A. The second resistive element 82 is located in the center of the second slot portion 40AQ in the circumferential direction of slot 40A.

[0081] The first slot portion 40AP has a first width WS1. The second slot portion 40AQ has a second width WS2. In the first embodiment, the first width WS1 and the second width WS2 are equal to each other. That is, the slot 40A has a constant width WS around its entire circumference. In the first embodiment, each of the first width WS1 and the second width WS2 can be 5 μm.

[0082] [Operation of the First Embodiment] The operation of the terahertz device 10 of the first embodiment will be described with reference to Figures 10 to 14. Figure 11 shows a partial planar structure of the comparative example terahertz device 10X. Figure 12 is a graph showing the relationship between the area of ​​each active element 60, 70 in a plan view and the frequency of the electromagnetic wave emitted by the terahertz device 10 when the arrangement positions of the first active element 60 and the second active element 70 are changed. Figure 13 is a graph showing the relationship between the area of ​​each active element 60, 70 in a plan view and the output power of the terahertz device 10 when the arrangement positions of the first active element 60 and the second active element 70 are changed. Figure 14 is a graph showing the relationship between the frequency of the electromagnetic wave emitted by the terahertz device 10 and the output power when the arrangement positions of the first active element 60 and the second active element 70 are changed. In Figures 12 to 14, the areas of the first active element 60 and the second active element 70 are equal in plan view. Also, in Figures 12 to 14, the diameter of the first electrode 41 is 80 μm.

[0083] As shown in Figure 11, the comparative example terahertz device 10X differs from the terahertz device 10 of the first embodiment mainly in the arrangement of the first active element 60 and the second active element 70. For this reason, the same reference numerals are used for components common to the terahertz device 10 of the first embodiment in the comparative example terahertz device 10X. In the following, the first active element 60 in the comparative example terahertz device 10X will be referred to as "first active element 60X," and the second active element 70 in the comparative example terahertz device 10X will be referred to as "second active element 70X."

[0084] In the comparative example terahertz device 10X, the first active element 60X and the second active element 70X are arranged in a point-symmetric relationship with respect to the center 41C of the first electrode 41. That is, the first active element 60X and the second active element 70X are located on a comparison line LX passing through the center 41C of the first electrode 41, and are positioned on either side of the first electrode 41. In the example shown in Figure 11, the comparison line LX is perpendicular to the second auxiliary line LB2 in a plan view. Therefore, the angle AX1 between the first active element 60X and the first resistive element 81 with respect to the center 41C of the first electrode 41, and the angle AX2 between the second active element 70X and the first resistive element 81 with respect to the center 41C of the first electrode 41, are both 90°.

[0085] As shown in Figure 10, the first active element 60 and the second active element 70 of the terahertz device 10 of the first embodiment are moved in the circumferential direction of the slot 40A relative to the first active element 60X and the second active element 70X (see Figure 11 for both). In other words, the first active element 60 and the second active element 70 are offset in the circumferential direction of the slot 40A with the position of the first active element 60X and the second active element 70X as the reference position. Hereafter, the first offset angle A is defined as the angle at which the first active element 60 is offset in the circumferential direction of the slot 40A relative to the first active element 60X. ｏｆｆ Let it be 1. The second offset angle A is the angle offset in the circumferential direction of the slot 40A of the second active element 70 relative to the second active element 70X. ｏｆｆ Let's assume it's 2. First offset angle A ｏｆｆ 1 can be defined by the angle between the comparison line LX and the first reference line LA1. Second offset angle Aｏｆｆ 2 can be defined by the angle formed between the comparison straight line LX and the second reference straight line LA2. In the example shown in FIG. 10, the first offset angle A ｏｆｆ 1 is 80°, and the second offset angle A ｏｆｆ 2 is 80°.

[0086] In the terahertz device 10 of the first embodiment, the first offset angle A ｏｆｆ 1 and the second offset angle A ｏｆｆ 2 correspond to the length LP of the first slot portion 40AP and the length LQ of the second slot portion 40AQ (both refer to FIG. 4) between the first active element 60 and the second active element 70. That is, changing the first offset angle A ｏｆｆ 1 and the second offset angle A ｏｆｆ 2 is equivalent to changing the length LP of the first slot portion 40AP and the length LQ of the second slot portion 40AQ. Therefore, the first offset angle A ｏｆｆ 1 and the second offset angle A ｏｆｆ 2, that is, the length LP of the first slot portion 40AP and the length LQ of the second slot portion 40AQ, can affect the impedance of the ring slot antenna 40R. Therefore, by adjusting the first offset angle A ｏｆｆ 1 and the second offset angle A ｏｆｆ 2, it is possible to adjust the impedance of the ring slot antenna 40R.

[0087] In the terahertz device 10X of the comparative example shown in FIG. 11, the first active element 60X and the second active element 70X are arranged on the comparison straight line LX. Therefore, it can also be said that the terahertz device 10X of the comparative example shown in FIG. 11 shows the case where the first offset angle A ｏｆｆ 1 and the second offset angle A ｏｆｆ 2 are 0°. Also, it can be said that the terahertz device 10X of the comparative example shown in FIG. 11 is in a state where the length LP of the first slot portion 40AP between the first active element 60X and the second active element 70X is equal to the length LQ of the second slot portion 40AQ.

[0088] FIG. 12 shows the first offset angle A ｏｆｆ1st and 2nd offset angle A ｏｆｆ This shows the relationship between the frequency of the electromagnetic waves emitted by the terahertz device 10 and the area of ​​each active element 60, 70 in a plan view, when 2 is 80°, 60°, 40°, 20°, and 0°. First offset angle A ｏｆｆ 1st and 2nd offset angle A ｏｆｆ When 2 is 0°, it corresponds to the case of the comparative example terahertz device 10X. Note that in Figures 12 to 14, the first offset angle A ｏｆｆ 1st and 2nd offset angle A ｏｆｆ When 2 is 80°, the graph is shown with black circles. First offset angle A ｏｆｆ 1st and 2nd offset angle A ｏｆｆ When 2 is 60°, the graph is shown with a triangular plot. First offset angle A ｏｆｆ 1st and 2nd offset angle A ｏｆｆ When 2 is 40°, the graph is shown with diamond-shaped plots. First offset angle A ｏｆｆ 1st and 2nd offset angle A ｏｆｆ When 2 is 20°, the graph is shown with an X mark. First offset angle A ｏｆｆ 1st and 2nd offset angle A ｏｆｆ When 2 is 0°, the graph is shown with a square plot.

[0089] As shown in Figure 12, the area of ​​each active element 60, 70 in a plan view depends on the frequency of the electromagnetic wave. In other words, the larger the area of ​​each active element 60, 70 in a plan view, the lower the frequency of the electromagnetic wave. Conversely, the smaller the area of ​​each active element 60, 70 in a plan view, the higher the frequency of the electromagnetic wave.

[0090] Also, the first offset angle A ｏｆｆ 1st and 2nd offset angle A ｏｆｆ It can be seen that the frequency of electromagnetic waves increases as 2 increases. In other words, if the area of ​​each active element 60, 70 in a plan view is the same, then the first offset angle A ｏｆｆ 1st and 2nd offset angle A ｏｆｆ The frequency of electromagnetic waves is highest when the angle is 80°.

[0091] Figure 13 shows the first offset angle A. ｏｆｆ 1st and 2nd offset angle A ｏｆｆ This shows the relationship between the output power of the terahertz device 10 and the area of ​​each active element 60, 70 in a plan view when 2 is 80°, 60°, 40°, 20°, and 0°.

[0092] As shown in Figure 13, the output power of the terahertz device 10 changes by changing the area of ​​each active element 60, 70 in a plan view, that is, by changing the frequency of the electromagnetic wave. Also, the first offset angle A ｏｆｆ 1st and 2nd offset angle A ｏｆｆ By changing 2, the output power of the terahertz device 10 changes. In this way, the first offset angle A ｏｆｆ 1st and 2nd offset angle A ｏｆｆ It is thought that changing parameter 2 changes the impedance of the ring slot antenna 40R.

[0093] First offset angle A ｏｆｆ 1st and 2nd offset angle A ｏｆｆ When 2 is 80°, the peak output power of the terahertz device 10 is the first offset angle A ｏｆｆ 1st and 2nd offset angle A ｏｆｆ The value of 2 is greater than when it is 60°, 40°, 20°, and 0°.

[0094] Figure 14 shows the first offset angle A ｏｆｆ 1st and 2nd offset angle A ｏｆｆ Figure 14 shows the relationship between the frequency of the electromagnetic waves emitted by the terahertz device 10 and the output power of the terahertz device 10 when 2 is 80°, 60°, 40°, 20°, and 0°. In Figure 14, the area of ​​each active element 60, 70 in a plan view is set to a preset value (for example, the area of ​​each active element 60, 70 in a plan view is 2 μm). ２ ) Here, the set value is the first offset angle A in Figure 13. ｏｆｆ 1st and 2nd offset angle A ｏｆｆ This is the value that represents the peak output power of the terahertz device 10 when 2 is 80°.

[0095] As shown in Figure 14, the first offset angle A ｏｆｆ 1st and 2nd offset angle A ｏｆｆ By changing 2, the relationship between the electromagnetic wave frequency and the output power of the terahertz device 10 is changed. First offset angle A ｏｆｆ 1st and 2nd offset angle A ｏｆｆ When 2 is 80°, the peak output power of the terahertz device 10 is the first offset angle A ｏｆｆ 1st and 2nd offset angle A ｏｆｆ The first offset angle A is greater than when 2 is 60°, 40°, 20°, and 0°. ｏｆｆ 1st and 2nd offset angle A ｏｆｆ When 2 is 80°, the frequency of the electromagnetic wave that results in the peak output power of the terahertz device 10 is the first offset angle A ｏｆｆ 1st and 2nd offset angle A ｏｆｆ 2 is higher than when it is 60°, 40°, 20°, and 0°.

[0096] Thus, in the first embodiment, the first offset angle A ｏｆｆ 1st and 2nd offset angle A ｏｆｆ Increasing 2 allows the frequency of the electromagnetic waves emitted by the terahertz device 10 to be increased, and the output power to be increased. First offset angle A ｏｆｆ 1st and 2nd offset angle A ｏｆｆ It can also be said that the impedance of the ring slot antenna 40R can be adjusted by changing 2. In the first embodiment, the first offset angle A ｏｆｆ 1st and 2nd offset angle A ｏｆｆ When 2 is 80°, the impedance between the ring slot antenna 40R and the first active element 60 and the second active element 70 is matched, so the peak output power of the terahertz device 10 increases.

[0097] [Effects of the First Embodiment] The terahertz device 10 of the first embodiment provides the following effects. (1-1) The terahertz device 10 includes a substrate 20 including a substrate surface 21, a conductive layer 40 provided on the substrate surface 21, an annular slot 40A provided in the conductive layer 40, and a first active element 60 and a second active element 70 arranged in the slot 40A for oscillating or detecting electromagnetic waves. The conductive layer 40 includes, in a plan view, a first electrode 41 arranged inside the slot 40A, and a second electrode 42 arranged outside the slot 40A in a plan view, surrounding the first electrode 41 via the slot 40A. In a plan view, if the straight line passing through the first active element 60 and the center 41C of the first electrode 41 is defined as the first reference line LA1, the second active element 70 is arranged in an asymmetrical position that is different from its position on the first reference line LA1 within the slot 40A.

[0098] In this configuration, the first active element 60 and the second active element 70 are positioned at locations different from those that are point-symmetrical with respect to the center 41C of the first electrode 41. By changing the positions of the first active element 60 and the second active element 70 in this way, the impedance of the ring slot antenna 40R can be adjusted. In other words, by changing the positions of the first active element 60 and the second active element 70, the impedance of the ring slot antenna 40R can be adjusted. And by adjusting the impedance, the output power of the terahertz device 10 can be improved.

[0099] (1-2) The frequency of the terahertz waves oscillated by the terahertz device 10 can be changed by changing the arrangement positions of the first active element 60 and the second active element 70. Therefore, by changing the arrangement positions of the first active element 60 and the second active element 70, the terahertz device 10 can oscillate terahertz waves of a desired frequency.

[0100] (1-3) In a plan view, the first auxiliary line LB1 is defined as a line passing through the center 41C of the first electrode 41 and perpendicular to the first reference line LA1. In a plan view, the second active element 70 is positioned closer to the first active element 60 with respect to the first auxiliary line LB1 in the direction in which the first reference line LA1 extends.

[0101] With this configuration, compared to a configuration in which the second active element 70 is positioned on the opposite side of the first active element 60 from the first auxiliary line LB1 in the direction in which the first reference line LA1 extends, the impedance is adjusted to approach impedance matching between the ring slot antenna 40R and the first active element 60 and the second active element 70, thereby improving the output power of the terahertz device 10.

[0102] (1-4) In the circumferential direction of slot 40A, the clockwise direction in a plan view is defined as the first circumferential direction W1, and the counterclockwise direction as the second circumferential direction W2. The distance DA from the first active element 60 to the second active element 70 in the first circumferential direction W1 is smaller than the distance DB from the first active element 60 to the second active element 70 in the second circumferential direction W2.

[0103] With this configuration, compared to a configuration where distances DA and DB are equal, the impedance is adjusted to approach impedance matching between the ring slot antenna 40R and the first active element 60 and the second active element 70, thereby improving the output power of the terahertz device 10.

[0104] (1-5) In a plan view, the line passing through the second active element 70 and the center 41C of the first electrode 41 is defined as the second reference line LA2. The angle A1 between the first reference line LA1 and the second reference line LA2 is less than 180°. With this configuration, the same effect as in (1-1) above can be obtained.

[0105] (1-6) The angle A1 between the first reference line LA1 and the second reference line LA2 is less than 90°. With this configuration, the impedance is adjusted to approach impedance matching between the ring slot antenna 40R and the first active element 60 and the second active element 70, compared to the case where the angle A1 between the first reference line LA1 and the second reference line LA2 is 90°, thereby improving the output power of the terahertz device 10.

[0106] (1-7) The angle A1 between the first reference line LA1 and the second reference line LA2 is 20°. With this configuration, compared to the case where the angle A1 between the first reference line LA1 and the second reference line LA2 is greater than 20° and less than 160°, the impedance is adjusted to approach impedance matching between the ring slot antenna 40R and the first active element 60 and the second active element 70, thereby improving the output power of the terahertz device 10.

[0107] (1-8) The terahertz device 10 further comprises a first resistive element 81 and a second resistive element 82 electrically connected to the first electrode 41 and the second electrode 42. With this configuration, parasitic oscillations are suppressed by the first resistive element 81 and the second resistive element 82, thereby stabilizing the oscillation of the terahertz device 10.

[0108] (1-9) In a plan view, the line connecting the center 41C of the first electrode 41, the first resistive element 81, and the second resistive element 82 is defined as the second auxiliary line LB2. In a plan view, the first active element 60 and the second active element 70 are arranged on both sides of the second auxiliary line LB2. With this configuration, the effects described in (1-1) above can be obtained.

[0109] (1-10) The terahertz device 10 includes a substrate 20 including a substrate surface 21, a conductive layer 40 provided on the substrate surface 21, an annular slot 40A provided in the conductive layer 40, and a first active element 60 and a second active element 70 arranged in the slot 40A for oscillating or detecting electromagnetic waves. The conductive layer 40 includes, in a plan view, a first electrode 41 located inside the slot 40A, and, in a plan view, a second electrode 42 located outside the slot 40A and surrounding the first electrode 41 via the slot 40A. The terahertz device 10 includes a first resistive element 81 and a second resistive element 82 electrically connected to the first electrode 41 and the second electrode 42. The first resistive element 81 and the second resistive element 82 are positioned point-symmetric with respect to the center 41C of the first electrode 41. The first active element 60 and the second active element 70 are positioned biased toward the first resistive element 81 in the circumferential direction of the slot 40A.

[0110] In this configuration, the first active element 60 and the second active element 70 are positioned biased toward the first resistive element 81 in the circumferential direction of the slot 40A. As a result, the first active element 60 and the second active element 70 are positioned in a location different from a point-symmetric position around the center 41C of the first electrode 41. By changing the position of the first active element 60 and the second active element 70 in this way, the impedance of the ring slot antenna 40R is adjusted. The output power of the terahertz device 10 can then be changed by adjusting the impedance. In other words, by changing the position of the first active element 60 and the second active element 70, the impedance can be adjusted to approach impedance matching between the ring slot antenna 40R and the first active element 60 and the second active element 70, thereby improving the output power of the terahertz device 10. In addition, parasitic oscillations are suppressed by the first resistive element 81 and the second resistive element 82, thus stabilizing the oscillation of the terahertz device 10.

[0111] (1-11) Let the first angle AR1 be the angle between the first resistive element 81 and the first active element 60 with respect to the center 41C of the first electrode 41. The first angle AR1 is less than 90°. Let the second angle AR2 be the angle between the first resistive element 81 and the second active element 70 with respect to the center 41C of the first electrode 41. The second angle AR2 is less than 90°.

[0112] With this configuration, the impedance is adjusted to approach impedance matching between the ring slot antenna 40R and the first active element 60 and the second active element 70, compared to the case where both the first angle AR1 and the second angle AR2 are 90°, thereby improving the output power of the terahertz device 10.

[0113] (1-12) Both the first angle AR1 and the second angle AR2 are less than 45°. With this configuration, the impedance is adjusted to approach impedance matching between the ring slot antenna 40R and the first active element 60 and the second active element 70, compared to the case where both the first angle AR1 and the second angle AR2 are between 45° and 135°, thus improving the output power of the terahertz device 10.

[0114] (1-13) Both the first angle AR1 and the second angle AR2 are 10°. With this configuration, the impedance is adjusted to approach impedance matching between the ring slot antenna 40R and the first active element 60 and the second active element 70, compared to the case where both the first angle AR1 and the second angle AR2 are greater than 10° and less than 170°, thereby improving the output power of the terahertz device 10.

[0115] (1-14) The substrate 20 includes a substrate back surface 22 opposite to the substrate surface 21. The terahertz device 10 includes a reflective layer 33 configured to reflect electromagnetic waves. The reflective layer 33 is provided on the substrate back surface 22. The reflective layer 33 is positioned to overlap with the slot 40A in a plan view. With this configuration, the terahertz device 10 can radiate electromagnetic waves in the direction that the substrate surface 21 of the substrate 20 faces.

[0116] (1-15) The first electrode pad 51 and the second electrode pad 52 are positioned at the corners 21A and 21B of the substrate 20. With this configuration, it is possible to suppress the first electrode pad 51 and the second electrode pad 52 from blocking electromagnetic waves that are reflected by the reflective layer 33 and directed toward the substrate surface 21.

[0117] <Second Embodiment> The terahertz device 10 of the second embodiment will be described with reference to Figures 15 and 16. In the terahertz device 10 of the second embodiment, the shape of the slot 40A is mainly different from that of the terahertz device 10 of the first embodiment. In the following, components common to the terahertz device 10 of the first embodiment will be denoted by the same reference numerals, and their descriptions will be omitted.

[0118] Figure 15 schematically shows an enlarged planar structure of slot 40A and its surroundings in the terahertz device 10 of the second embodiment. As shown in Figure 15, slot 40A, similar to the first embodiment, includes a first slot portion 40AP from the first active element 60 to the second active element 70 in the first circumferential direction W1, and a second slot portion 40AQ from the first active element 60 to the second active element 70 in the second circumferential direction W2. The second auxiliary line LB2 is located in the first slot portion 40AP. The first auxiliary line LB1 is located in the second slot portion 40AQ. In the circumferential direction of slot 40A, the length LP of the first slot portion 40AP is shorter than the length LQ of the second slot portion 40AQ.

[0119] Similar to the first embodiment, the first slot portion 40AP has a first width WS1. The second slot portion 40AQ has a second width WS2. In the second embodiment, the first width WS1 is different from the second width WS2. In one example, the second width WS2 is smaller than the first width WS1. In another example, the second width WS2 may be smaller than the longer side of the rectangular first active element 60 and second active element 70 in a plan view. In the second embodiment, the first width WS1 can be 5 μm. The second width WS2 can be 4 μm.

[0120] Figure 16 is a graph showing the relationship between the second width WS2 of the second slot portion 40AQ and the output power of the terahertz device 10. In Figure 16, the second width WS2 is changed by modifying the portion of the outer edge 40AB of the slot 40A that corresponds to the second slot portion 40AQ. On the other hand, in Figure 16, the inner edge 40AA of the slot 40A is not changed. In Figure 16, the diameter of the first electrode 41 and the area of ​​each active element 60, 70 in a plan view are the same as in the first embodiment.

[0121] As shown in Figure 16, the output power of the terahertz device 10 increases as the second width WS2 increases from 1 μm to 4 μm. When the second width WS2 is 4 μm or greater, the output power of the terahertz device 10 decreases as the second width WS2 increases. In the range where the second width WS2 is between 4 μm and 5 μm, the rate of decrease in the output power of the terahertz device 10 with respect to the change in the second width WS2 is smaller than the rate of decrease in the output power of the terahertz device 10 with respect to the change in the second width WS2 in the range where the second width WS2 is greater than 5 μm. As can be seen from Figure 16, the output power of the terahertz device 10 increases in the range where the second width WS2 is between 3 μm and 6 μm. In particular, the output power of the terahertz device 10 increases in the range where the second width WS2 is between 4 μm and 5 μm. When the second width WS2 is 4 μm, the output power of the terahertz device 10 is at its maximum. In this way, the impedance of the ring slot antenna 40R can be adjusted by changing the second width WS2. In the second embodiment, as shown in Figure 16, when the second width WS2 is 4 μm, the impedance is adjusted to be as close as possible to impedance matching between the ring slot antenna 40R and the first active element 60 and the second active element 70.

[0122] [Effects of the Second Embodiment] In addition to the effects of the terahertz device 10 of the first embodiment, the following effects can be obtained with the terahertz device 10 of the second embodiment.

[0123] (2-1) Slot 40A includes a first slot portion 40AP from the first active element 60 to the second active element 70 in the first circumferential direction W1, and a second slot portion 40AQ from the first active element 60 to the second active element 70 in the second circumferential direction W2. The first slot portion 40AP has a first width WS1. The second slot portion 40AQ has a second width WS2. The second width WS2 is different from the first width WS1.

[0124] With this configuration, the output power of the terahertz device 10 can be changed by changing the second width WS2 of the second slot portion 40AQ relative to the first width WS1 of the first slot portion 40AP. Therefore, the impedance of the ring slot antenna 40R can be adjusted by changing the second width WS2 of the second slot portion 40AQ relative to the first width WS1 of the first slot portion 40AP. By adjusting the impedance of the ring slot antenna 40R using such adjustments to the first width WS1 and second width WS2 of slot 40A, the output power of the terahertz device 10 can be improved.

[0125] (2-2) The second width WS2 is smaller than the first width WS1. With this configuration, the impedance is adjusted to approach impedance matching between the ring slot antenna 40R and the first active element 60 and the second active element 70, compared to the case where the second width WS2 is larger than the first width WS1, and thus the output power of the terahertz device 10 can be improved.

[0126] (2-3) The second width WS2 is 4 μm. With this configuration, the impedance is adjusted to approach impedance matching between the ring slot antenna 40R and the first active element 60 and the second active element 70, compared to the case where the second width WS2 is less than 4 μm or greater than 4 μm, so that the output power of the terahertz device 10 can be improved.

[0127] <Examples of Modifications> Each of the above embodiments can be modified and implemented as follows. Furthermore, each of the above embodiments and the following examples of modifications can be combined with each other to the extent that they do not contradict each other technically.

[0128] In the second embodiment, the relationship between the first width WS1 of the first slot portion 40AP and the second width WS2 of the second slot portion 40AQ in slot 40A can be arbitrarily changed. For example, as shown in Figure 17, the second width WS2 may be greater than the first width WS1. Also, the second width WS2 of the second slot portion 40AQ of slot 40A is not limited to 4 μm. The second width WS2 may be less than 4 μm or greater than 4 μm.

[0129] In the second embodiment, the second width WS2 of the second slot portion 40AQ of the slot 40A may be greater than or equal to the longer side of the first active element 60 and the second active element 70, which are rectangular in plan view.

[0130] In each embodiment, the positions of the first resistive element 81 and the second resistive element 82 can be arbitrarily changed. In one example, as shown in Figure 18, the first resistive element 81 may be positioned in the center between the first active element 60 and the second active element 70 in the circumferential direction of the slot 40A. In other words, the first distance D1 between the first active element 60 and the first resistive element 81 in the circumferential direction of the slot 40A and the third distance D3 between the second active element 70 and the first resistive element 81 in the circumferential direction of the slot 40A may be equal to each other.

[0131] Furthermore, in the example shown in Figure 18, the first resistive element 81 and the second resistive element 82 are arranged symmetrically with respect to the first electrode 41. Therefore, the second distance D2 between the first active element 60 and the second resistive element 82 in the circumferential direction of the slot 40A and the fourth distance D4 between the second active element 70 and the second resistive element 82 in the circumferential direction of the slot 40A may be equal to each other. As a result, the third distance D3 is smaller than the fourth distance D4.

[0132] Here, the third distance D3 can be defined by the length of the line segment connecting the center of the first resistive element 81 and the center of the second active element 70 in the circumferential direction of slot 40A. More specifically, the third distance D3 can be defined by the distance from the center of the first resistive element 81 to the center of the second active element 70 in the first circumferential direction W1 of slot 40A. In other words, the third distance D3 can also be said to be the shortest distance between the center of the first resistive element 81 and the center of the second active element 70 in the circumferential direction of slot 40A. Furthermore, the fourth distance D4 can be defined by the length of the line segment connecting the center of the second resistive element 82 and the center of the second active element 70 in the circumferential direction of slot 40A. More specifically, the fourth distance D4 can be defined by the distance from the center of the second resistive element 82 to the center of the second active element 70 in the second circumferential direction W2 of slot 40A. In other words, the fourth distance D4 can also be said to be the shortest distance between the second resistive element 82 and the second active element 70 in the circumferential direction of slot 40A.

[0133] The third distance D3 may be defined as the distance between the side of the first resistive element 81 closer to the second active element 70 in the circumferential direction of slot 40A and the side of the second active element 70 closer to the first resistive element 81. The fourth distance D4 may be defined as the distance between the side of the second resistive element 82 closer to the second active element 70 in the circumferential direction of slot 40A and the side of the second active element 70 closer to the second resistive element 82.

[0134] The first angle AR1, which is the angle between the first resistive element 81 and the first active element 60 with respect to the center 41C of the first electrode 41, and the second angle AR2, which is the angle between the first resistive element 81 and the second active element 70 with respect to the center 41C of the first electrode 41, are equal to each other. In one example, the first angle AR1 and the second angle AR2 are less than 90°. In another example, the first angle AR1 and the second angle AR2 are less than 45°. In the example shown in Figure 18, both the first angle AR1 and the second angle AR2 are 10°. When the first angle AR1 and the second angle AR2 are equal to each other, it can also be said that the first active element 60 and the second active element 70 are arranged in a symmetrical relationship with respect to the second auxiliary line LB2.

[0135] The first resistive element 81 and the second resistive element 82 may extend radially through the slot 40A in a plan view. In the example shown in Figure 18, the first resistive element 81 and the second resistive element 82 penetrate the slot 40A in its radial direction.

[0136] - In each embodiment, the first resistive element 81 and the second resistive element 82 may be positioned at locations other than symmetrical positions on either side of the first electrode 41. - In each embodiment, as shown in Figure 19, the first resistive element 81 and the second resistive element 82 may be omitted.

[0137] In each embodiment, the distance DA from the first active element 60 to the second active element 70 in the first circumferential direction W1 may be greater than the distance DB from the first active element 60 to the second active element 70 in the second circumferential direction W2.

[0138] In each embodiment, the sizes of the first active element 60 and the second active element 70 can be arbitrarily changed. In one example, the first active element 60 and the second active element 70 may penetrate the slot 40A in their radial direction. That is, the long side of the first active element 60 may be larger than the width WS of the slot 40A. The long side of the second active element 70 may be larger than the width WS of the slot 40A.

[0139] In each embodiment, the first offset angle A with respect to the first active element 60 ｏｆｆ Second offset angle A with respect to 1 and the second active element 70 ｏｆｆ 2 were equal to each other, but are not limited to this. In one example, as shown in Figure 20, the first offset angle A ｏｆｆ 1st and 2nd offset angle A ｏｆｆ The two values ​​may be different from each other. In the example shown in Figure 20, the first offset angle A ｏｆｆ 1 is the second offset angle A ｏｆｆ It is less than 2.

[0140] - In each embodiment, as shown in Figure 21, the first active element 60 and the second active element 70 may be arranged on one side with respect to the second auxiliary line LB2. - In each embodiment, the first distance D1 between the first resistive element 81 and the first active element 60 in the circumferential direction of the slot 40A in a plan view may be greater than or equal to the second distance D2 between the second resistive element 82 and the first active element 60 in the circumferential direction of the slot 40A.

[0141] In each embodiment, the second active element 70 may be positioned on the opposite side of the first auxiliary line LB1 from the first active element 60 in the direction in which the first reference line LA1 extends.

[0142] In each embodiment, the positions of the first active element 60 and the second active element 70 can be arbitrarily changed within the range where the angle A1 between the first reference line LA1 and the second reference line LA2 is less than 180°. The angle A1 between the first reference line LA1 and the second reference line LA2 may be 90° or more and less than 180°.

[0143] In each embodiment, the relative positions of the first active element 60, the second active element 70, the first resistive element 81, and the second resistive element 82 can be arbitrarily changed. In one example, the first angle AR1, which is the angle between the first resistive element 81 and the first active element 60 with respect to the center 41C of the first electrode 41, may be 45° or more and less than 90°. In one example, the second angle AR2, which is the angle between the first resistive element 81 and the second active element 70 with respect to the center 41C of the first electrode 41, may be 45° or more and less than 90°. In one example, the first angle AR1 may be greater than 90°. In one example, the second angle AR2 may be greater than 90°. In one example, the first angle AR1 and the second angle AR2 may be equal to each other or different.

[0144] - In each embodiment, the shapes of the first active element 60 and the second active element 70 in plan view are not limited to a rectangular shape including a long side and a short side, but can be arbitrarily changed. - In each embodiment, the arrangement positions of the first resistive element 81 and the second resistive element 82 can be arbitrarily changed. In one example, the first resistive element 81 and the second resistive element 82 may be arranged in positions different from symmetrical positions with respect to the first electrode 41.

[0145] - In each embodiment, the reflective layer 33 may be omitted. - In each embodiment, the placement positions of the first electrode pad 51 and the second electrode pad 52 are not limited to the edges of the substrate 20 in a plan view, but can be arbitrarily changed.

[0146] In each embodiment, the shape of the slot 40A in plan view can be arbitrarily changed. In one example, as shown in Figures 22 to 24, the slot 40A may be a rectangular ring in plan view. The slot 40A includes a first portion 401 and a second portion 402 extending along the X direction, and a third portion 403 and a fourth portion 404 extending along the Y direction. The center 41C of the first electrode 41 can be defined by the center of the rectangle in plan view that forms the first electrode 41.

[0147] In the example shown in Figure 22, the slot 40A may be a rectangular ring shape with the Y direction being the longitudinal direction and the X direction being the short direction in a plan view. That is, the X-direction dimension of the first portion 401 and the second portion 402 is shorter than the Y-direction dimension of the third portion 403 and the fourth portion 404. The outer shape of the first electrode 41 (the shape of the outer edge of the first electrode 41) may be a rectangle with the Y direction being the long side and the X direction being the short side in a plan view. The arrangement of the first active element 60 and the second active element 70 may be the same as in each of the embodiments described above. In the example shown in Figure 22, the first active element 60 and the second active element 70 may be arranged at both ends in the X-direction of the first portion 401 that extends in the short direction (X-direction) of the slot 40A. The first active element 60 and the second active element 70 may be in the same position relative to each other in the Y-direction.

[0148] The first slot portion 40AP of slot 40A is composed of the portion of the first portion 401 of slot 40A between the first active element 60 and the second active element 70 in the X direction. The second slot portion 40AQ is composed of the second portion 402, the third portion 403, and the fourth portion 404. Therefore, the distance DA from the first active element 60 to the second active element 70 in the clockwise direction of the circumferential direction of slot 40A is smaller than the distance DB from the first active element 60 to the second active element 70 in the counterclockwise direction of the circumferential direction of slot 40A. In other words, the length of the first slot portion 40AP is shorter than the length of the second slot portion 40AQ. Also, in one example, the first width WS1 of the first slot portion 40AP is equal to the second width WS2 of the second slot portion 40AQ. Note that the first width WS1 and the second width WS2 can be arbitrarily changed.

[0149] In the example shown in Figure 23, the slot 40A may be a rectangular ring shape with the X direction being the longitudinal direction and the Y direction being the short direction in a plan view. That is, the X-direction dimensions of the first portion 401 and the second portion 402 are longer than the Y-direction dimensions of the third portion 403 and the fourth portion 404. The outer shape of the first electrode 41 may be a rectangle with the X direction being the long side and the Y direction being the short side in a plan view. The arrangement of the first active element 60 and the second active element 70 may be the same as in the first embodiment. In the example shown in Figure 23, the first active element 60 and the second active element 70 may be spaced apart from each other in the X direction in the central portion of the first portion 401 of the slot 40A in the X direction. The first active element 60 and the second active element 70 may be in the same position in the Y direction.

[0150] The first slot portion 40AP of slot 40A is composed of the portion of the central part of the first portion 401 of slot 40A between the first active element 60 and the second active element 70 in the X direction. The second slot portion 40AQ is composed of the second portion 402, the third portion 403, and the fourth portion 404 of slot 40A, and the portion of the first portion 401 other than the first slot portion 40AP. Therefore, the distance DA from the first active element 60 to the second active element 70 in the clockwise direction of the circumferential direction of slot 40A is smaller than the distance DB from the first active element 60 to the second active element 70 in the counterclockwise direction of the circumferential direction of slot 40A. In other words, the length of the first slot portion 40AP is shorter than the length of the second slot portion 40AQ. Also, in one example, the first width WS1 of the first slot portion 40AP is equal to the second width WS2 of the second slot portion 40AQ. Note that the first width WS1 and the second width WS2 can be changed as desired.

[0151] As shown in Figure 24, the slot 40A may be a rectangular ring with equal dimensions in the X and Y directions in a plan view. That is, the X-direction dimensions of the first portion 401 and the second portion 402 are equal to the Y-direction dimensions of the third portion 403 and the fourth portion 404. The outer shape of the first electrode 41 may be square in a plan view. The arrangement of the first active element 60 and the second active element 70 may be the same as in the first embodiment. In the example shown in Figure 24, the first active element 60 and the second active element 70 may be spaced apart from each other in the X direction in the central portion of the first portion 401 of the slot 40A in the X direction. The first active element 60 and the second active element 70 may be in the same position in the Y direction.

[0152] The first slot portion 40AP of slot 40A is composed of the portion of the central part of the first portion 401 of slot 40A between the first active element 60 and the second active element 70 in the X direction. The second slot portion 40AQ is composed of the second portion 402, the third portion 403, and the fourth portion 404 of slot 40A, and the portion of the first portion 401 other than the first slot portion 40AP. Therefore, the distance DA from the first active element 60 to the second active element 70 in the clockwise direction of the circumferential direction of slot 40A is smaller than the distance DB from the first active element 60 to the second active element 70 in the counterclockwise direction of the circumferential direction of slot 40A. In other words, the length of the first slot portion 40AP is shorter than the length of the second slot portion 40AQ. Also, in one example, the first width WS1 of the first slot portion 40AP is equal to the second width WS2 of the second slot portion 40AQ. Note that the first width WS1 and the second width WS2 can be changed as desired.

[0153] Figure 25 shows the relationship between the frequency of electromagnetic waves emitted by the terahertz device 10, which includes the slot 40A shown in Figures 22 to 24, and the output power of the terahertz device 10. In Figure 25, the triangular plots correspond to the slot 40A shown in Figure 22, the circular plots correspond to the slot 40A shown in Figure 23, and the square plots correspond to the slot 40A shown in Figure 24.

[0154] As can be seen from Figure 25, by changing the dimensions of the rectangular annular slot 40A in the X and Y directions, the frequency of the electromagnetic wave at which the output power peaks and the output power can be changed, respectively. Specifically, as the ratio of the dimension in the X direction to the dimension in the Y direction increases, the peak output power increases. Also, the frequency of the electromagnetic wave emitted by the terahertz device 10 including the square annular slot 40A shown in Figure 24 is higher than the frequency of the electromagnetic wave emitted by the terahertz device 10 including the rectangular annular slot 40A shown in Figures 22 and 23. The frequency of the electromagnetic wave emitted by the terahertz device 10 including the rectangular annular slot 40A shown in Figure 23 is higher than the frequency of the electromagnetic wave emitted by the terahertz device 10 including the rectangular annular slot 40A shown in Figure 22. In this way, the impedance of the ring slot antenna 40R can be changed by changing the shape of the slot 40A in a plan view.

[0155] Furthermore, the rectangular annular slot 40A shown in Figures 22 to 24 may have its first to fourth portions 401 to 404 extending in directions that intersect both the X and Y directions in a plan view. In other words, it is not limited to the first portion 401 and the second portion 402 extending along the X direction, nor is it limited to the third portion 403 and the fourth portion 404 extending along the Y direction.

[0156] Furthermore, the rectangular ring-shaped slot 40A is not limited to the examples shown in Figures 22 to 24, but can be arbitrarily changed. For example, the slot 40A may be an unequal-sided rectangular ring in plan view.

[0157] In one example, as shown in Figures 26 and 27, the slot 40A may be an elliptic ring in plan view. In this case, the outer shape of the first electrode 41 (the shape of the outer edge of the first electrode 41) may be elliptical in plan view. More specifically, as shown in Figure 26, the slot 40A may be an elliptic ring with the X direction as the major axis and the Y direction as the minor axis in plan view. In this case, the outer shape of the first electrode 41 may be elliptical with the X direction as the major axis and the Y direction as the minor axis in plan view. The arrangement of the first active element 60 and the second active element 70 may be the same as in the first embodiment.

[0158] As shown in Figure 27, the slot 40A may be an elliptical ring shape with the major axis in the Y direction and the minor axis in the X direction in a plan view. In this case, the outer shape of the first electrode 41 may be an ellipse with the major axis in the Y direction and the minor axis in the X direction in a plan view. The arrangement of the first active element 60 and the second active element 70 may be the same as in the first embodiment.

[0159] In one example, as shown in Figures 28 to 30, the slot 40A may be a triangular ring in plan view. The slot 40A includes a first part 405, a second part 406, and a third part 407, corresponding to each side of the triangle. The center 41C of the first electrode 41 can be defined by the center of the triangle in plan view that forms the first electrode 41.

[0160] In the example shown in Figure 28, the slot 40A may be an isosceles triangular ring in plan view. In this case, the outer shape of the first electrode 41 (the outer edge of the first electrode 41) may be an isosceles triangle in plan view. The first portion 405 of the slot 40A corresponds to the base of the isosceles triangle, and the second portion 406 and the third portion 407 correspond to the equal sides of the isosceles triangle. The first portion 405 may be provided so as to extend along the X direction. The arrangement of the first active element 60 and the second active element 70 may be the same as in the first embodiment. In the example shown in Figure 28, the first active element 60 and the second active element 70 may be arranged in the first portion 405 of the slot 40A in plan view. The first active element 60 and the second active element 70 may be in the same position relative to each other in the Y direction.

[0161] The first slot portion 40AP of slot 40A is composed of the portion of the central part of the first portion 405 of slot 40A between the first active element 60 and the second active element 70 in the X direction. The second slot portion 40AQ is composed of the second portion 406 and the third portion 407 of slot 40A, and the portion of the first portion 405 other than the first slot portion 40AP. Therefore, the distance DA from the first active element 60 to the second active element 70 in the clockwise direction of the circumferential direction of slot 40A is smaller than the distance DB from the first active element 60 to the second active element 70 in the counterclockwise direction of the circumferential direction of slot 40A. In other words, the length of the first slot portion 40AP is shorter than the length of the second slot portion 40AQ. Also, in one example, the first width WS1 of the first slot portion 40AP is equal to the second width WS2 of the second slot portion 40AQ. Note that the first width WS1 and the second width WS2 can be changed as desired.

[0162] In the example shown in Figure 29, the slot 40A may be an equilateral triangular ring in plan view. In this case, the outer shape of the first electrode 41 may be an equilateral triangle in plan view. The slot 40A may be provided such that the first portion 405 extends along the X direction in plan view. The arrangement of the first active element 60 and the second active element 70 may be the same as in the first embodiment. In the example shown in Figure 29, the first active element 60 and the second active element 70 may be arranged in the first portion 405 of the slot 40A in plan view. The first active element 60 and the second active element 70 may be in the same position relative to each other in the Y direction.

[0163] The first slot portion 40AP of slot 40A is composed of the portion of the central part of the first portion 405 of slot 40A between the first active element 60 and the second active element 70 in the X direction. The second slot portion 40AQ is composed of the second portion 406 and the third portion 407 of slot 40A, and the portion of the first portion 405 other than the first slot portion 40AP. Therefore, the distance DA from the first active element 60 to the second active element 70 in the clockwise direction of the circumferential direction of slot 40A is smaller than the distance DB from the first active element 60 to the second active element 70 in the counterclockwise direction of the circumferential direction of slot 40A. In other words, the length of the first slot portion 40AP is shorter than the length of the second slot portion 40AQ. Also, in one example, the first width WS1 of the first slot portion 40AP is equal to the second width WS2 of the second slot portion 40AQ. Note that the first width WS1 and the second width WS2 can be changed as desired.

[0164] In the example shown in Figure 30, the slot 40A may be a right-angled triangular ring in plan view. In this case, the outer shape of the first electrode 41 may be a right-angled triangle in plan view. The first portion 405 of the slot 40A corresponds to an adjacent side of the right-angled triangle. The second portion 406 corresponds to an opposite side of the right-angled triangle. The third portion 407 corresponds to the hypotenuse of the right-angled triangle. The first portion 405 of the slot 40A extends along the X direction. The arrangement of the first active element 60 and the second active element 70 may be the same as in the first embodiment. In the example shown in Figure 30, the first active element 60 and the second active element 70 may be arranged in the first portion 405 of the slot 40A in plan view. The first active element 60 and the second active element 70 may be in the same position relative to each other in the Y direction.

[0165] The first slot portion 40AP of slot 40A is composed of the portion of the first portion 405 of slot 40A between the first active element 60 and the second active element 70 in the X direction. The second slot portion 40AQ is composed of the second portion 406 and the third portion 407 of slot 40A, and the portion of the first portion 405 other than the first slot portion 40AP. Therefore, the distance DA from the first active element 60 to the second active element 70 in the clockwise direction of the circumferential direction of slot 40A is smaller than the distance DB from the first active element 60 to the second active element 70 in the counterclockwise direction of the circumferential direction of slot 40A. In other words, the length of the first slot portion 40AP is shorter than the length of the second slot portion 40AQ. Also, in one example, the first width WS1 of the first slot portion 40AP is equal to the second width WS2 of the second slot portion 40AQ. Note that the first width WS1 and the second width WS2 can be changed as desired.

[0166] The arrangement of the first active element 60 and the second active element 70 shown in Figures 28 to 30 can be arbitrarily changed. In one example, the first active element 60 and the second active element 70 may be arranged in either the second portion 406 or the third portion 407 of the slot 40A.

[0167] Furthermore, the triangular ring-shaped slot 40A is not limited to the examples shown in Figures 28 to 30, but can be arbitrarily changed. For example, the slot 40A may be an unequal-sided triangular ring in plan view.

[0168] Furthermore, although not shown in the diagram, the slot 40A may be a polygonal ring with five or more sides in plan view. In this case, the outer shape of the first electrode 41 may be a polygon with five or more sides in plan view. In other words, if the slot 40A is a polygonal ring in plan view, the outer shape of the first electrode 41 may be a polygon with five or more sides in plan view. Also, the polygonal ring slot 40A may be a polygonal ring in which the length of the part corresponding to one side of the outer shape of the first electrode 41 is different from the length of the part corresponding to the other side of the first electrode 41.

[0169] In each embodiment, the external shape of the second electrode 42 in plan view can be arbitrarily changed. In one example, the external shape of the second electrode 42 may be rectangular, circular, or elliptical in plan view. Alternatively, the external shape of the second electrode 42 may be a polygon with five or more sides in plan view.

[0170] One or more of the various examples described in this disclosure may be combined to the extent that they do not contradict the technical context. As used in this disclosure, the term “on” includes the meanings of “on” and “above” unless the context clearly indicates otherwise. Therefore, for example, the expression “the first element is positioned on the second element” is intended to mean that in one embodiment the first element may be in contact with the second element and positioned directly on the second element, while in other embodiments the first element may be positioned above the second element without contact with it. In other words, the term “on” does not preclude structures in which other elements are formed between the first and second elements.

[0171] The Z-direction used in this disclosure does not necessarily have to be vertical, nor does it have to perfectly coincide with the vertical. Therefore, the various structures described herein are not limited to the "up" and "down" in the Z-axis direction being the same as the "up" and "down" in the vertical direction. For example, the X-direction may be vertical, or the Y-direction may be vertical.

[0172] <Note> The technical concepts that can be grasped from this disclosure are described below. Not intended to be limiting, but to aid understanding, the components described in this note are denoted by the corresponding reference numerals of the components in the embodiments described above. The reference numerals are provided as examples to aid understanding, and the components described in each note should not be limited to those indicated by the reference numerals.

[0173] [Note 1] The device comprises: a substrate (20) including a substrate surface (21); a conductive layer (40) provided on the substrate surface (21); an annular slot (40A) provided in the conductive layer (40); and a first active element (60) and a second active element (70) disposed within the slot (40A) for oscillating or detecting electromagnetic waves, wherein the conductive layer (40) includes: a first electrode (41) disposed inside the slot (40A) in a plan view taken from a direction perpendicular to the substrate surface (21); and a second electrode (42) disposed outside the slot (40A) in the plan view, surrounding the first electrode (41) via the slot (40A), In the plan view, if the line passing through the first active element (60) and the center (41C) of the first electrode (41) is defined as the first reference line (LA1), then the second active element (70) is positioned in an asymmetric position within the slot (40A) that is different from its position on the first reference line (LA1).

[0174] [Note 2] In the plan view, the first auxiliary line (LB1) is defined as a line passing through the center (41C) of the first electrode (41) and perpendicular to the first reference line (LA1), and in the plan view, the second active element (70) is positioned closer to the first active element (60) with respect to the first auxiliary line (LB1) in the direction in which the first reference line (LA1) extends. The terahertz device according to Note 1.

[0175] [Note 3] In the circumferential direction of the slot (40A), the clockwise direction in the plan view is defined as the first circumferential direction (W1) and the counterclockwise direction as the second circumferential direction (W2), and the distance (DA) from the first active element (60) to the second active element (70) in the first circumferential direction (W1) is smaller than the distance (DB) from the first active element (60) to the second active element (70) in the second circumferential direction (W2), as described in Note 1.

[0176] [Note 4] In the plan view, if the line passing through the second active element (70) and the center (41C) of the first electrode (41) is defined as the second reference line (LA2), then the angle (A1) between the first reference line (LA1) and the second reference line (LA2) is less than 180°, as described in Note 1.

[0177] [Note 5] The terahertz device as described in Note 4, wherein the angle (A1) between the first reference line (LA1) and the second reference line (LA2) is less than 90°.

[0178] [Note 6] The terahertz device as described in Note 4, wherein the angle (A1) between the first reference line (LA1) and the second reference line (LA2) is 20°.

[0179] [Note 7] The terahertz device according to any one of Notes 1 to 6, wherein the slot (40A) is annular in plan view.

[0180] [Note 8] The slot (40A) includes a first slot portion (40AP) from the first active element (60) to the second active element (70) in the first circumferential direction (W1), and a second slot portion (40AQ) from the first active element (60) to the second active element (70) in the second circumferential direction (W2), wherein the first slot portion (40AP) has a first width (WS1), and the second slot portion (40AQ) has a second width (WS2), and the second width (WS2) is different from the first width (WS1), as described in Note 3.

[0181] [Note 9] The terahertz device described in Note 8, wherein the second width (WS2) is smaller than the first width (WS1).

[0182] [Note 10] The terahertz device according to Note 8 or 9, wherein the first active element (60) and the second active element (70) are rectangular in shape in the plan view, including a long side and a short side, and the second width (WS2) is smaller than the long side of the first active element (60) and the second active element (70).

[0183] [Note 11] The terahertz apparatus according to any one of Notes 8 to 10, wherein the second width (WS2) is 4 μm.

[0184] [Note 12] The terahertz device according to any one of Notes 1 to 7, wherein the slot (40A) has a constant width around its entire circumference.

[0185] [Note 13] A terahertz device according to any one of Notes 1 to 12, comprising a first resistive element (81) and a second resistive element (82) electrically connected in parallel to the first active element (60) and the second active element (70).

[0186] [Note 14] The terahertz device according to Note 13, wherein the first resistive element (81) and the second resistive element (82) are arranged symmetrically with respect to the first electrode (41).

[0187] [Note 15] The terahertz device according to Note 13 or 14, wherein in the plan view, the first distance (D1) between the first resistive element (81) and the first active element (60) in the circumferential direction of the slot (40A) is smaller than the second distance (D2) between the second resistive element (82) and the first active element (60) in the circumferential direction of the slot (40A).

[0188] [Note 16] In the plan view, the line connecting the center (41C) of the first electrode (41), the first resistive element (81), and the second resistive element (82) is defined as the second auxiliary line (LB2), and in the plan view, the first active element (60) and the second active element (70) are arranged on both sides of the second auxiliary line (LB2), as described in any one of Notes 13 to 15.

[0189] [Note 17] In the plan view, the first active element (60) and the second active element (70) are arranged symmetrically with respect to the second auxiliary line (LB2) as described in Note 16, the terahertz device.

[0190] [Note 18] The terahertz device according to any one of Notes 1 to 17, wherein the external shape of the second electrode (42) is rectangular in the plan view.

[0191] [Note 19] The terahertz device according to any one of Notes 1 to 18, wherein the first active element (60) and the second active element (70) are any of the following: resonant tunnel diode, tannet diode, INPAT diode, GaAs field-effect transistor, GaN FET, high electron mobility transistor, heterojunction bipolar transistor, Schottky barrier diode, or CMOSFET.

[0192] [Note 20] The terahertz device according to any one of Notes 13 to 17, wherein the third distance (D3) between the first resistive element (81) and the second active element (70) in the circumferential direction of the slot (40A) is smaller than the fourth distance (D4) between the second resistive element (82) and the second active element (70) in the circumferential direction of the slot (40A).

[0193] [Note 21] The terahertz device according to any one of Notes 13 to 17, wherein the first resistive element (81) and the second resistive element (82) penetrate the slot (40A) in its radial direction.

[0194] [Note 22] The terahertz device according to any one of Notes 1 to 21, wherein the first active element (60) and the second active element (70) penetrate the slot (40A) in its radial direction.

[0195] [Note 23] In the plan view, the first distance (D1) between the first resistive element (81) and the first active element (60) in the circumferential direction of the slot (40A) is equal to the third distance (D3) between the first resistive element (81) and the second active element (70) in the circumferential direction of the slot (40A), as described in any one of Notes 13 to 17.

[0196] [Note 24] A substrate (20) including a substrate surface (21), a conductive layer (40) provided on the substrate surface (21), an annular slot (40A) provided in the conductive layer (40), and a first active element (60) and a second active element (70) disposed within the slot (40A) for oscillating or detecting electromagnetic waves, wherein the conductive layer (40) includes a first electrode (41) located inside the slot (40A) in a plan view from a direction perpendicular to the substrate surface (21), and a second electrode (42) located outside the slot (40A) in the plan view, surrounding the first electrode (41) via the slot (40A), and further comprising a first resistive element (81) and a second resistive element (82) electrically connected to the first electrode (41) and the second electrode (42), The first resistive element (81) and the second resistive element (82) are arranged in a point-symmetric position with respect to the center (41C) of the first electrode (41), and the first active element (60) and the second active element (70) are arranged biased toward the first resistive element (81) in the circumferential direction of the slot (40A) in the terahertz device (10).

[0197] [Note 25] The terahertz device described in Note 24, wherein the first angle (AR1) is less than 90°, and the angle between the first resistive element (81) and the first active element (60) with respect to the center (41C) of the first electrode (41).

[0198] [Note 26] The terahertz device according to Note 24 or 25, wherein the second angle (AR2) is less than 90°, and the angle between the first resistive element (81) and the second active element (70) with respect to the center (41C) of the first electrode (41).

[0199] [Note 27] The terahertz device as described in Note 24, wherein the angle between the first resistive element (81) and the first active element (60) with respect to the center (41C) of the first electrode (41) is defined as the first angle (AR1), and the angle between the first resistive element (81) and the second active element (70) with respect to the center (41C) of the first electrode (41) is defined as the second angle (AR2), then both the first angle (AR1) and the second angle (AR2) are less than 90°, and the first angle (AR1) and the second angle (AR2) are equal to each other.

[0200] [Note 28] The terahertz device described in Note 27, wherein both the first angle (AR1) and the second angle (AR2) are less than 45°.

[0201] [Note 29] The terahertz device according to Note 27, wherein both the first angle (AR1) and the second angle (AR2) are 10°.

[0202] [Note 30] The terahertz apparatus according to any one of Notes 1 to 29, wherein the substrate (20) includes a substrate back surface (22) opposite to the substrate surface (21), and includes a reflective layer (33) provided on the substrate back surface (22) and configured to reflect electromagnetic waves, and the reflective layer (33) is arranged to overlap with the slot (40A) in the plan view.

[0203] [Note 31] A terahertz device according to any one of Notes 1 to 30, comprising: a first electrode pad (51) and a second electrode pad (52) provided on the substrate surface (21); a first connecting wire (53) connecting the first electrode pad (51) and the first electrode (41); and a second connecting wire (54) connecting the second electrode pad (52) and the second electrode (42).

[0204] [Note 32] The terahertz apparatus according to Note 31, wherein the first electrode pad (51) and the second electrode pad (52) are arranged at the corners (21A, 21B) of the substrate (20) in the plan view.

[0205] [Note 33] The terahertz device according to any one of Notes 1 to 32, wherein the second electrode (42) is square, rectangular, circular, or elliptical in plan view.

[0206] [Note 34] The terahertz device according to any one of Notes 1 to 6, wherein the slot (40A) is a quadrangular ring, a polygonal ring, or an elliptical ring in the plan view, and the outer shape of the first electrode (41) is a square, a rectangle, a polygon with pentagons or more, or an ellipse in the plan view.

[0207] The above description is illustrative only. Those skilled in the art will recognize that many more possible combinations and substitutions are possible beyond the components and methods (manufacturing processes) enumerated for the purpose of illustrating the technology of this disclosure. This disclosure is intended to encompass all alternatives, variations, and modifications that fall within the scope of this disclosure, including the claims.

[0208] 10...Terahertz device, 20...Substrate, 21...Substrate surface, 21A, 21B...Corner, 22...Substrate back, 23-26...Substrate side, 31...Semiconductor substrate, 311...Surface, 312...Back, 32...Insulating layer, 321...Insulating surface, 322...Insulating back, 33...Reflective layer, 331...Reflective surface, 332...Reflective back, 40...Conductive layer, 40A...Slot, 40AA...Inner edge, 40AB...Outer edge, 40AP...First slot portion, 40AQ...Second slot portion, 40 1-404...First to fourth parts, 405-407...First to third parts, 41...First electrode, 41C...Center of the first electrode, 42...Second electrode, 421...First side, 422...Second side, 423...Third side, 424...Fourth side, 431, 432...Connection part, 441, 442...Connection part, 51...First electrode pad, 52...Second electrode pad, 53...First connection wiring, 531...First wiring, 532...Second wiring, 533...Lower wiring, 534...Via, 54...Second connection wiring, 5 41...First wiring, 542...Second wiring, 60...First active element, 61a...Semiconductor layer, 61b...GaInAs layer, 62a, 62b...GaInAs layer, 63a, 63b...GaInAs layer, 64a, 64b...AlAs layer, 6 5... InGaAs layer, 70... Second active element, 71a... Semiconductor layer, 71b... GaInAs layer, 72a, 72b... GaInAs layer, 73a, 73b... GaInAs layer, 74a, 74b... AlAs layer, 75... InGaA s layer, 81...first resistive element, 811...first end, 812...second end, 82...second resistive element, 821...first end, 822...second end, 83A, 83B...via, 84A, 84B...strap wiring, 85A, 85B...via, A1...angle between the first reference line and the second reference line, AR1...first angle between the first active element and the first resistive element with respect to the center of the first electrode, AR2...second angle between the second active element and the first resistive element with respect to the center of the first electrode, A ｏｆｆ 1...First offset angle, A ｏｆｆ2...Second offset angle, WS...Slot width, WS1...First width (width of the first slot portion), WS2...Second width (width of the second slot portion), LA1...First reference line, LA2...Second reference line, LB1...First auxiliary line, LB2...Second auxiliary line, R1...Region, W1...First circumferential direction, W2...Second circumferential direction, DA...Distance between the first active element and the second active element in the first circumferential direction, DB...Distance between the first active element and the second active element in the second circumferential direction D1...the distance between the child, D2...the first distance between the first resistive element and the first active element in the circumferential direction of the slot, D3...the third distance between the first resistive element and the second active element in the circumferential direction of the slot, D4...the fourth distance between the second resistive element and the second active element in the circumferential direction of the slot, LP...length of the first slot portion, LQ...length of the second slot portion.

Claims

1. A terahertz device comprising: a substrate including a substrate surface; a conductive layer provided on the substrate surface; an annular slot provided in the conductive layer; and a first active element and a second active element disposed in the slot for oscillating or detecting electromagnetic waves, wherein the conductive layer includes: a first electrode disposed inside the slot in a plan view viewed from a direction perpendicular to the substrate surface; and a second electrode disposed outside the slot in a plan view, surrounding the first electrode through the slot, wherein, in a plan view, if a straight line passing through the center of the first active element and the center of the first electrode is defined as a first reference line, the second active element is disposed in an asymmetric position within the slot that is different from its position on the first reference line.

2. In the plan view, a line passing through the center of the first electrode and perpendicular to the first reference line is defined as the first auxiliary line, and in the plan view, the second active element is positioned closer to the first active element with respect to the first auxiliary line in the direction in which the first reference line extends.

3. In the circumferential direction of the slot, the clockwise direction in the plan view is defined as the first circumferential direction and the counterclockwise direction as the second circumferential direction, wherein the distance from the first active element to the second active element in the first circumferential direction is smaller than the distance from the first active element to the second active element in the second circumferential direction, according to claim 1.

4. In the plan view, if the line passing through the center of the second active element and the center of the first electrode is defined as the second reference line, the angle between the first reference line and the second reference line is less than 180°, as described in claim 1.

5. The terahertz device according to claim 4, wherein the angle between the first reference line and the second reference line is less than 90°.

6. The terahertz apparatus according to claim 4, wherein the angle between the first reference line and the second reference line is 20°.

7. The terahertz apparatus according to any one of claims 1 to 6, wherein the slot is annular in plan view.

8. The terahertz device according to claim 3, wherein the slot includes a first slot portion in the first circumferential direction from the first active element to the second active element, and a second slot portion in the second circumferential direction from the first active element to the second active element, the first slot portion having a first width, and the second slot portion having a second width, the second width being different from the first width.

9. The terahertz device according to claim 8, wherein the second width is smaller than the first width.

10. The terahertz device according to claim 8 or 9, wherein the first active element and the second active element are rectangular in shape, including a long side and a short side in the plan view, and the second width is smaller than the long side of the first active element and the second active element.

11. The terahertz apparatus according to any one of claims 8 to 10, wherein the second width is 4 μm.

12. The terahertz apparatus according to any one of claims 1 to 7, wherein the slot has a constant width around its entire circumference.

13. A terahertz device according to any one of claims 1 to 12, comprising a first resistive element and a second resistive element electrically connected in parallel to the first active element and the second active element.

14. The terahertz device according to claim 13, wherein the first resistive element and the second resistive element are arranged symmetrically with respect to the first electrode.

15. The terahertz device according to claim 13 or 14, wherein in the plan view, the first distance between the first resistive element and the first active element in the circumferential direction of the slot is smaller than the second distance between the second resistive element and the first active element in the circumferential direction of the slot.

16. In the plan view, the first active element and the second active element are arranged on both sides of the second auxiliary line, with the line connecting the center of the first electrode, the first resistive element, and the second resistive element being a second auxiliary line.

17. The terahertz device according to claim 16, wherein, in the plan view, the first active element and the second active element are arranged symmetrically with respect to the second auxiliary line.

18. The terahertz apparatus according to any one of claims 1 to 17, wherein the external shape of the second electrode is rectangular in the plan view.

19. The terahertz device according to any one of claims 1 to 18, wherein the first active element and the second active element are any of a resonant tunnel diode, a tannet diode, an INPAT diode, a GaAs field-effect transistor, a GaN FET, a high electron-mobility transistor, a heterojunction bipolar transistor, a Schottky barrier diode, or a CMOSFET.

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