Terahertz device

Abstract

This terahertz device includes slots formed in a conductive layer, connection slits formed in the conductive layer, and active elements provided inside the slots. The slots are formed in an annular shape. The conductive layer includes first electrodes partitioned by the slots, and a second electrode located outside the slots. The active elements are respectively provided to the first electrodes and are disposed at positions sandwiching the first electrodes with respect to the center of the slots, when viewed from a direction perpendicular to the surface.

Description

Terahertz Device

[0001] The present disclosure relates to terahertz devices.

[0002] In recent years, as electronic devices such as transistors have become increasingly miniaturized and their size has reached nanoscale, a phenomenon known as the quantum effect has become observable. Development is underway to utilize this quantum effect to realize ultrafast devices and devices with new functions.

[0003] In such an environment, attempts are being made to utilize electromagnetic waves in the frequency range known as the terahertz band, which has a frequency of 0.1 THz to 10 THz, to perform high-capacity communication, information processing, imaging, measurement, etc. This frequency range combines the properties of both light and radio waves, and if devices operating in this frequency band can be realized, they could be used for a wide range of applications, including the aforementioned imaging, high-capacity communication, and information processing, as well as measurements in various fields such as physical analysis, astronomy, and biology.

[0004] As an element for emitting or receiving electromagnetic waves in the terahertz band, for example, a terahertz device having a structure in which a resonant tunneling diode and a fine antenna are integrated is known (see, for example, Patent Document 1).

[0005] Japanese Patent Application Laid-Open No. 2020-115500

[0006] Terahertz devices are used as light sources that output electromagnetic waves with frequencies in the terahertz band or as detectors that detect electromagnetic waves with frequencies in the terahertz band, and there is a demand for higher output and improved resolution characteristics in such terahertz devices.

[0007] a plurality of connecting slits formed in the conductive layer; and a plurality of active elements disposed within the plurality of slots for generating or detecting electromagnetic waves, each of the plurality of slots being formed in a ring shape; a plurality of first electrodes respectively partitioned by the plurality of slots; a connection line disposed within the plurality of connecting slits and electrically connecting the first electrodes located inside two adjacent slots among the plurality of slots; and a second electrode located outside the plurality of slots; each of the plurality of connecting slits connecting the two slots and formed to insulate the connection line from the second electrode; and the plurality of active elements including two active elements disposed for each of the plurality of first electrodes, the two active elements being disposed at positions sandwiching the first electrode with respect to the center of each of the plurality of slots in a planar view viewed from a direction perpendicular to the surface.

[0008] According to the terahertz device according to one aspect of the present disclosure, it is possible to improve characteristics.

[0009] FIG. 1 is a schematic plan view of an exemplary terahertz device according to a first embodiment. FIG. 2 is a schematic perspective view of the terahertz device of FIG. 1. FIG. 3 is a schematic cross-sectional view taken along line F3-F3 of FIG. 1. FIG. 4 is a schematic plan view illustrating the arrangement of a ring slot, a connecting slit, and an active element of the terahertz device of FIG. 1. FIG. 5 is a schematic plan view of the active element of the terahertz device of FIG. 1 and its periphery. FIG. 6 is a schematic plan view of the active element of the terahertz device of FIG. 1 and its periphery. FIG. 7 is a schematic cross-sectional view of the active element of FIGS. 5 and 6 and its periphery. FIG. 8 is a schematic plan view of the resistive element of FIG. 1 and its periphery. FIG. 9 is a schematic cross-sectional view of the resistive element of FIG. 8 and its periphery. FIG. 10 is a schematic plan view of an exemplary terahertz device according to a second embodiment. FIG. 11 is an enlarged plan view of the terahertz device of FIG. 10. FIG. 12 is a schematic plan view of an exemplary terahertz device according to a third embodiment. FIG. 13 is a schematic plan view of an exemplary terahertz device according to a fourth embodiment. Fig. 14 is a schematic plan view of an exemplary terahertz device according to a fifth embodiment. Fig. 15 is a schematic plan view of an exemplary terahertz device according to a sixth embodiment. Fig. 16 is a schematic plan view of an exemplary terahertz device according to a seventh embodiment. Fig. 17 is a schematic plan view of an exemplary terahertz device according to an eighth embodiment. Fig. 18 is a schematic plan view showing an active element of the terahertz device of Fig. 17 and its periphery. Fig. 19 is a schematic plan view of the active element of the terahertz device of Fig. 17 and its periphery. Fig. 20 is a schematic cross-sectional view showing the active element and resistive element of Fig. 19.

[0010] Hereinafter, several embodiments of the terahertz device of the present disclosure will be described with reference to the accompanying drawings. Note that for simplicity and clarity of explanation, the components shown in the drawings are not necessarily drawn to scale. Also, for ease of understanding, hatching lines may be omitted in cross-sectional views. The accompanying drawings merely illustrate embodiments of the present disclosure and should not be considered to limit the present disclosure. Terms such as "first," "second," and "third" in the present disclosure are used merely to distinguish between objects and do not rank the objects.

[0011] The following detailed description includes devices, systems, and methods embodying exemplary embodiments of the present disclosure. This detailed description is merely illustrative in nature and is not intended to limit the embodiments of the present disclosure or the application and uses of such embodiments.

[0012] The phrase "at least one" as used herein means "one or more" of the desired options. As an example, the phrase "at least one" as used herein means "only one option" or "both of two options" when the number of options is two. As another example, the phrase "at least one" as used herein means "only one option" or "any combination of two or more options" when the number of options is three or more.

[0013] First Embodiment A terahertz device 100 according to a first embodiment will be described with reference to FIGS. 1 to 9. (Schematic Configuration of Terahertz Device) FIG. 1 is a schematic plan view of an exemplary terahertz device 100 according to a first embodiment. FIG. 2 is a schematic perspective view of the terahertz device of FIG. 1. FIG. 3 is a schematic cross-sectional view taken along line F3-F3 in FIG. 1. FIG. 4 is a schematic plan view showing some components of the terahertz device 100 of FIG. 1, illustrating the arrangement of slots 121 and 122, first electrodes 141 and 142, and active elements 171a, 171b, 172a, and 172b. Note that the term "planar view" used in this disclosure refers to viewing the terahertz device 100 in the Z-axis direction of the mutually orthogonal X, Y, and Z axes shown in FIG. 1.

[0014] 1 to 4, the terahertz device 100 includes a substrate 10. The substrate 10 is formed in a flat plate shape. As shown in Fig. 1, the substrate 10 is formed in a rectangular parallelepiped shape. In one example, the substrate 10 may be formed in a rectangular shape in which the length in the X-axis direction is longer than the length in the Y-axis direction.

[0015] The substrate 10 includes a front surface 11, a back surface 12, and multiple side surfaces 13, 14, 15, and 16. The front surface 11 and the back surface 12 of the substrate 10 face opposite each other in the Z-axis direction. Therefore, "plan view" refers to a view perpendicular to the front surface 11 of the substrate 10. Furthermore, "perpendicular" does not only refer to a strictly perpendicular view, but also includes a view that is approximately perpendicular within the scope of the effects of the first embodiment. The shape of the front surface 11 in plan view is rectangular. In the first embodiment, the side surfaces 13 to 16 of the substrate 10 face either the X-axis direction or the Y-axis direction. The side surfaces 13 and 14 extend along the XZ plane. The side surfaces 13 and 14 face opposite each other in the Y-axis direction. The side surfaces 15 and 16 extend along the YZ plane. The side surfaces 15 and 16 face opposite each other in the X-axis direction. In the first embodiment, the X-axis direction corresponds to the "first direction" and the Y-axis direction corresponds to the "second direction."

[0016] As shown in Figures 2 and 3, the substrate 10 includes a semiconductor substrate 20 and an insulating layer 30 on the semiconductor substrate 20. The semiconductor substrate 20 is formed in a flat plate shape. As shown in Figure 1, the shape of the semiconductor substrate 20 in a planar view is rectangular. In one example, the shape of the semiconductor substrate 20 in a planar view is rectangular. The shape of the semiconductor substrate 20 in a planar view may be a square shape or other shape. The shape of the semiconductor substrate 20 in a planar view is not limited to a rectangular shape, and may be a circular shape, an elliptical shape, or a polygonal shape.

[0017] The semiconductor substrate 20 is formed 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), Si (silicon), SiC (silicon carbide), GaN (gallium nitride), and single crystal AlN (aluminum nitride). In one example, the semiconductor substrate 20 is formed of a material containing InP.

[0018] The semiconductor substrate 20 includes a substrate front surface 21 and a substrate back surface 22. The substrate front surface 21 and the substrate back surface 22 face opposite each other. The substrate front surface 21 faces the same side as the front surface 11, and the substrate back surface 22 faces the same side as the back surface 12. The semiconductor substrate 20 has substrate side surfaces that form part of each of the side surfaces 13 to 16. Because the substrate front surface 21 faces the same side as the front surface 11, the Z-axis direction is perpendicular to the substrate front surface 21.

[0019] The terahertz device 100 includes an insulating layer 30 provided on a semiconductor substrate 20. A substrate surface 21 of the semiconductor substrate 20 is covered with the insulating layer 30. The insulating layer 30 is made of an insulating material. For example, the insulating layer 30 is made of silicon oxide (SiO ２ In one example, the insulating layer 30 may be formed over the entire substrate surface 21 of the semiconductor substrate 20.

[0020] The insulating layer 30 has an insulating surface 31 and an insulating back surface 32 opposite to the insulating surface 31. The insulating surface 31 faces the same side as the substrate surface 21, and the insulating back surface 32 faces the same side as the substrate back surface 22. The insulating surface 31 constitutes the front surface 11. The insulating back surface 32 is in contact with the substrate surface 21 of the semiconductor substrate 20. Note that another member such as an insulating layer may be interposed between the substrate surface 21 of the semiconductor substrate 20 and the insulating layer 30. The insulating layer 30 has insulating side surfaces that constitute a part of each of the side surfaces 13 to 16.

[0021] The terahertz device 100 includes a conductive layer 110 formed on the surface 11 of the substrate 10. The conductive layer 110 is formed on a portion of the surface 11 of the substrate 10. The conductive layer 110 is formed of at least one metal material selected from the group consisting of gold (Au), silver (Ag), aluminum (Al), copper (Cu), titanium (Ti), titanium nitride (TiN), and platinum (Pt). It can also be said that the conductive layer 110 contains at least one of Au, Ag, Al, Cu, Ti, and Pt. In one example, the conductive layer 110 is formed of a material containing Au. The conductive layer 110 is formed by, for example, sputtering. The conductive layer 110 may also be formed of a stacked structure of multiple metal layers.

[0022] (Slots, connecting slits) The terahertz device 100 of the first embodiment may include two slots 121, 122 formed in the conductive layer 110. The two slots 121, 122 are arranged spaced apart from each other along the X-axis direction. The two slots 121, 122 are arranged side by side along the side surfaces 13, 14 of the substrate 10. The arrangement direction of the two slots 121, 122 may be changed as appropriate. The two slots 121, 122 are formed in an annular shape.

[0023] It should be noted that the term "annular" as used in this disclosure refers not only to any structure that forms a continuous shape or loop without an end, but also to generally loop-shaped structures with gaps, such as, for example, a C-shape. Thus, an explicit reference to a "closed annular" refers to any structure that forms a continuous shape or loop without an end, while an explicit reference to an "open annular" refers to a generally loop-shaped structure with gaps. Such "annular" shapes can include not only circular shapes, but also any shapes that include multiple corners, such as square or rounded corners.

[0024] The slots 121 and 122 are formed in an open annular shape. The slots 121 and 122 include first ends 121a and 122a and second ends 121b and 122b, respectively. The first ends 121a and 122a and the second ends 121b and 122b may be spaced apart in the Y-axis direction, which is perpendicular to the X-axis direction. The slots 121 and 122 are formed such that the first ends 121a and 122a are positioned in the same direction as the second ends 121b and 122b in the Y-axis direction. The slot 121 is formed in an annular shape that is open toward the side surface 16 of the substrate 10 in the X-axis direction. The slot 122 is formed in an annular shape that is open toward the side surface 15 of the substrate 10 in the X-axis direction. It can be said that the slots 121 and 122 are formed in annular shapes that are open toward the adjacent slots 121 and 122. In the first embodiment, slot 121 corresponds to the "first slot" and slot 122 corresponds to the "second slot."

[0025] The terahertz device 100 may also include two connecting slits 131a and 131b formed in the conductive layer 110. The two connecting slits 131a and 131b connect the two slots 121 and 122. The two connecting slits 131a and 131b are formed to extend along the X-axis direction in which the two connected slots 121 and 122 are aligned. The connecting slit 131a is formed to connect the first ends 121a and 122a of the two slots 121 and 122. The connecting slit 131b is formed to connect the second ends 121b and 122b of the two slots 121 and 122. It can be said that the connecting slits 131a and 131b in the first embodiment are formed to connect the two adjacent slots 121 and 122.

[0026] (First Electrode, Second Electrode) The conductive layer 110 includes first electrodes 141, 142 that are partitioned by slots 121, 122. In one example, the first electrodes 141, 142 are formed in a circular shape in a plan view. The first electrodes 141, 142 are arranged spaced apart from each other in the X-axis direction. It can be said that the first electrodes 141, 142 are arranged side by side along the side surfaces 13, 14 of the substrate 10.

[0027] The conductive layer 110 includes a second electrode 150 located outside the slots 121 and 122. In one example, the second electrode 150 is formed in a substantially rectangular shape. In a plan view, the second electrode 150 includes a first side 151 and a second side 152 that extend parallel to each other, and a third side 153 and a fourth side 154 that are perpendicular to the first side 151 and the second side 152. In one example, the second electrode 150 is formed in a rectangular shape in which the lengths of the first side 151 and the second side 152 are greater than the lengths of the third side 153 and the fourth side 154. In one example, the second electrode 150 is arranged such that the first side 151 and the second side 152 extend in the X-axis direction in a plan view. Note that the second electrode 150 may be formed in a square shape in which the lengths of the first side 151 and the second side 152 are equal to the lengths of the third side 153 and the fourth side 154. The second electrode 150 may be rectangular in shape, with the lengths of the third side 153 and the fourth side 154 being greater than the lengths of the first side 151 and the second side 152 .

[0028] (Connection Line) The conductive layer 110 includes a connection line 161 disposed in the connecting slits 131a and 131b. The connection line 161 extends in the X-axis direction along the connecting slits 131a and 131b. A first end of the connection line 161 is electrically connected to the first electrode 141, and a second end of the connection line 161 is electrically connected to the first electrode 142. The connection line 161 can be said to electrically connect the first electrodes 141 and 142 located inside two slots 121 and 122 adjacent to each other in the X-axis direction. The connecting slits 131a and 131b can be said to be formed to insulate the connection line 161 from the second electrode 150. The connection line 161, insulated from the second electrode 150 by the connecting slits 131a and 131b, can be a coplanar waveguide (CPW).

[0029] (Active Elements) The terahertz device 100 includes active elements 171a and 171b provided in the slot 121 and active elements 172a and 172b provided in the slot 122. The slots 121 and 122 define the first electrodes 141 and 142 in the conductive layer 110. It can be said that the terahertz device 100 includes two active elements 171a and 171b provided for the first electrode 141 and two active elements 172a and 172b provided for the first electrode 142. The conductive layer 110 includes a second electrode 150 located outside the slots 121 and 122. It can be said that the terahertz device 100 includes active elements 171a, 171b, 172a, and 172b arranged between the first electrodes 141 and 142 and the second electrode 150.

[0030] In the present disclosure, an active element can be referred to as an element that oscillates or detects electromagnetic waves. Furthermore, an active element can be referred to as an element that converts electromagnetic waves into electrical energy. Note that electromagnetic waves include the concepts of either light or radio waves, or both. An active element can be referred to as an element that oscillates electromagnetic waves in a predetermined frequency band, for example, the terahertz band (terahertz waves). In this case, the active element can be referred to as a terahertz element that oscillates terahertz waves. Furthermore, for example, the active element can be an element that detects terahertz waves, which are electromagnetic waves in a predetermined frequency band, for example, the terahertz band. In this case, the active element can be referred to as a terahertz element that receives terahertz waves. In one example, the frequency band of terahertz waves is equal to or greater than 0.1 THz and equal to or less than 10 THz.

[0031] For example, the active elements 171a, 171b, 172a, and 172b may be resonant tunneling diodes (RTDs). The active elements 171a, 171b, 172a, and 172b may be diodes or transistors other than RTDs. Examples of other active elements include tunnel injection transit time (TUNNETT) diodes, impact ionization avalanche transit time (IMPATT) diodes, GaAs-based field effect transistors (FETs), GaN-based FETs, high electron mobility transistors (HEMTs), heterojunction bipolar transistors (HBTs), and complementary metal-oxide-semiconductor (CMOS) FETs.

[0032] The active elements 171a, 171b, 172a, and 172b are rectangular in plan view. However, the shape of the active elements 171a, 171b, 172a, and 172b in plan view is not limited to a rectangular shape and may be a circular shape, an elliptical shape, or a polygonal shape.

[0033] The sizes of the slots 121 and 122 may be set according to the wavelengths of the electromagnetic waves generated or detected by the active elements 171a, 171b, 172a, and 172b arranged in the slots 121 and 122. In one example, the size of the slots 121 (122) may be set so that the distance between the active elements 171a and 171b (172a and 172b) in the circumferential direction of the slots 121 (122) is equal to or close to half the effective wavelength λg. The effective wavelength λg may be the wavelength of the terahertz waves propagating inside the terahertz device 100.

[0034] The active elements 171a, 171b, 172a, and 172b convert the supplied electrical energy into electromagnetic waves by oscillation. As a result, the active elements 171a, 171b, 172a, and 172b oscillate electromagnetic waves in a desired frequency band. Also, the active elements 171a, 171b, 172a, and 172b receive electromagnetic waves and convert the electromagnetic waves into electrical energy. As a result, the active elements 171a, 171b, 172a, and 172b detect electromagnetic waves in a desired frequency band.

[0035] As shown in FIGS. 1 and 4 , the active elements 171a and 171b are arranged in positions sandwiching the first electrode 141 with respect to the center O1 of the slot 121 in a plan view. In one example, the active element 171a is arranged at the first end 121a of the slot 121. The active element 171b is arranged in a position within the slot 121 opposite the first end 121a with respect to the center O1 of the slot 121. It can be said that the active elements 171a and 171b are arranged in positions point-symmetric with respect to the center O1 of the slot 121. It can also be said that the active elements 171a and 171b are arranged in positions sandwiching the first electrode 141 with respect to a reference line LM1 passing through the center O1 of the slot 121. The center O1 of the slot 121 coincides with the center of the first electrode 141 surrounded by the slot 121. It can be said that the reference line LM1 passes through the center of the first electrode 141. The active elements 171a and 171b can be said to be arranged in the slot 121 on a reference line LM1 that passes through the center of the first electrode 141. The reference line LM1 is inclined with respect to the X-axis in a planar view. The reference line LM1 can be said to be inclined with respect to the connection line 161 in a planar view. In the first embodiment, the active element 171a corresponds to the "first active element," and the active element 171b corresponds to the "second active element."

[0036] The active elements 172a and 172b are arranged in positions sandwiching the first electrode 142 with respect to the center O2 of the slot 122 in a plan view. In one example, the active element 172b is arranged at the second end 122b of the slot 122. The active element 172a is arranged in a position within the slot 122 opposite the second end 122b with respect to the center O2 of the slot 122. It can be said that the active elements 172a and 172b are arranged in positions point-symmetric with respect to the center O2 of the slot 122 within the slot 122. It can also be said that the active elements 172a and 172b are arranged in positions sandwiching the first electrode 142 within the slot 122 on a reference line LM2 passing through the center O2 of the slot 122. The center O2 of the slot 122 coincides with the center of the first electrode 142 surrounded by the slot 122. It can be said that the reference line LM2 passes through the center of the first electrode 142. The active elements 172a and 172b can be said to be arranged in the slot 122 on a reference line LM2 that passes through the center of the first electrode 142. The reference line LM2 is inclined with respect to the X-axis in a plan view. The reference line LM2 can be said to be inclined with respect to the connection line 161 in a plan view. In the first embodiment, the active element 172b corresponds to the "third active element," and the active element 172a corresponds to the "fourth active element."

[0037] In one example, the reference line LM1 of the slot 121 is parallel to the reference line LM2 of the slot 122. The angles between the connection line 161 and the reference lines LM1 and LM2, which are the inclinations of the reference lines LM1 and LM2 with respect to the connection line 161, are equal to each other.

[0038] The active elements 171a and 171b are connected to the first electrode 141 and the second electrode 150 so as to oscillate in a state where the phases are reversed (antiphase) to each other. The active elements 171a and 171b are connected between the first electrode 141 and the second electrode 150 so as to be in parallel to each other.

[0039] The active elements 172a and 172b are connected to the first electrode 142 and the second electrode 150 so as to oscillate in a state where the phases are reversed (anti-phase) to each other. The active elements 172a and 172b are connected between the first electrode 142 and the second electrode 150 so as to be in parallel to each other.

[0040] The end face of the conductive layer 110 facing the slot 121 in which the active elements 171a and 171b are arranged, i.e., the first electrode 141, and the portion of the second electrode 150 surrounding the first electrode 141, constitutes the slot antenna 121R. The end face of the conductive layer 110 facing the slot 122 in which the active elements 172a and 172b are arranged, i.e., the first electrode 142, and the portion of the second electrode 150 surrounding the first electrode 142, constitutes the slot antenna 122R.

[0041] The terahertz device 100 of the first embodiment can be said to include two slot antennas 121R and 122R arranged in the X-axis direction. The first electrodes 141 and 142 constituting the two slot antennas 121R and 122R are electrically connected by a connection line 161. Therefore, the terahertz device 100 of the first embodiment can operate the two slot antennas 121R and 122R in synchronization. The terahertz device 100 of the first embodiment can radiate higher output electromagnetic waves than, for example, a terahertz device including one active element or a terahertz device including one slot antenna. In other words, the terahertz device 100 of the first embodiment can achieve improved characteristics.

[0042] In the terahertz device 100 according to the first embodiment, in order to improve the efficiency of electromagnetic wave radiation or detection at the two slot antennas 121R and 122R, it is preferable that the directions of currents flowing between the two slot antennas 121R and 122R are aligned. In Fig. 4, dashed arrows indicate an example of a current I1 flowing between the active elements 171a and 171b connected to the first electrode 141 and a current I2 flowing between the active elements 172a and 172b connected to the first electrode 141. The directions of the currents I1 and I2 change depending on the drive signals supplied to the active elements 171a, 171b, 172a, and 172b.

[0043] To align the directions of these currents I1 and I2, it is preferable to operate the active elements 171a and 172a in phase and operate the active elements 171b and 172b in antiphase relative to the active elements 171a and 172a. In other words, the terahertz device 100 is preferably configured to operate the active element 171a arranged at the first end 121a of the slot 121 and the active element 172b arranged at the second end 122b of the slot 122 in antiphase. The length of the connection line 161 may be adjusted so that the active elements 171a and 172b are in antiphase. The length of the connection line 161 may be (2n-1) / 2 (n is an integer greater than or equal to 1) of the effective wavelength λg of the terahertz device 100 or a value close to that. In one example, the length of the connection line 161 may be ½ (=λg / 2) of the effective wavelength λg of the terahertz device 100. It can be said that the connection line 161 is set so that the currents flowing in the same direction through the two connected first electrodes 141, 142. It can also be said that the length of the connection line 161 is set so that the active elements 171a and 172b located at both ends operate in opposite phases.

[0044] 1 , the terahertz device 100 may include resistive elements R1 and R2 connected to the first electrodes 141 and 142, respectively. The resistive elements R1 and R2 are arranged outside the slots 121 and 122. The resistive elements R1 and R2 are arranged at positions overlapping with the second electrode 150.

[0045] The resistor elements R1 and R2 are arranged on either side of the first electrodes 141 and 142. The resistor elements R1 and R2 are arranged symmetrically with respect to the centers O1 and O2 of the slots 121 and 122. The resistor elements R1 and R2 are connected in parallel to the active elements 171a, 171b, 172a, and 172b arranged in the slots 121 and 122. The resistor elements R1 and R2 suppress parasitic oscillation. The resistor elements R1 and R2 stabilize the oscillation in the active elements 171a, 171b, 172a, and 172b.

[0046] The resistive elements R1 and R2 may be connected to virtual short-circuit points with respect to the first electrodes 141 and 142. The virtual short-circuit points are portions where the electric field strength of the terahertz waves generated by the active elements 171a, 171b, 172a, and 172b that oscillate in opposite phases is relatively low, and can be referred to as pseudo short-circuit points. The electric fields generated by the active elements 171a, 171b, 172a, and 172b that oscillate in opposite phases are added together in opposite phases.

[0047] 4, the locations where the electric field strength is relatively low are located between the two active elements 171a, 171b, 172a, 172b, and along auxiliary lines LS1, LS2 that are perpendicular to reference lines LM1, LM2 connecting the active elements 171a, 171b, 172a, 172b, and that pass through centers O1, O2 of the slots 121, 122. The resistive elements R1, R2 may be connected to the first electrodes 141, 142 in accordance with the auxiliary lines LS1, LS2.

[0048] (First Electrode Pad, Second Electrode Pad) As shown in FIGS. 1 and 2 , the conductive layer 110 includes two first electrode pads 181 and 182. The two first electrode pads 181 and 182 are provided corresponding to the two first electrodes 141 and 142. The number of first electrode pads 181 and 182 may be changed as appropriate. In one example, the terahertz device 100 may be provided with one first electrode pad 181. The one first electrode pad 181 may be connected to either the first electrode 141 or the first electrode 142, or to both the first electrode 141 and the first electrode 142.

[0049] The first electrode pads 181 and 182 are disposed apart from the second electrode 150. The second electrode 150 includes recesses 1551 and 1552 recessed from the second side 152 toward the first electrodes 141 and 142. The first electrode pads 181 and 182 are disposed in the recesses 1551 and 1552, respectively.

[0050] The first electrode pads 181, 182 are electrically connected to the first electrodes 141, 142 by connection wirings 51, 52. The connection wirings 51, 52 may include lower wirings 61 and vias 62, 63. The lower wirings 61 are disposed in the insulating layer 30. The lower wirings 61 may be disposed between the semiconductor substrate 20 and the conductive layer 110. The vias 62 electrically connect the lower wirings 61 to the first electrode pads 181, 182. The vias 63 electrically connect the lower wirings 61 to the first electrodes 141, 142. The connection wirings 51, 52 may be connected to virtual short-circuit points with respect to the first electrodes 141, 142. In one example, the vias 63 are connected to virtual short-circuit points of the first electrodes 141, 142 with respect to the slots 121, 122. This makes it possible to suppress leakage of electromagnetic waves to the connection wirings 51, 52.

[0051] The lower wiring 61 and the vias 62 and 63 are formed of at least one metal material selected from the group consisting of Au, Ag, Al, Cu, Ti, TiN, and Pt. It can also be said that the lower wiring 61 and the vias 62 and 63 contain at least one of Au, Ag, Al, Cu, Ti, and Pt. In one example, the lower wiring 61 and the vias 62 and 63 are formed of a material containing Au.

[0052] The second electrode pads 181b and 182b are located on the opposite side of the first electrodes 141 and 142 from the first electrode pads 181 and 182, and are set as part of the second electrode 150. The second electrode pads 181b and 182b are set apart from each other in the X-axis direction along the first side 151 of the second electrode 150.

[0053] (Reflective Layer) The terahertz device 100 includes a reflective layer 40 provided on the rear surface 12 of the substrate 10. The reflective layer 40 is in contact with the rear surface 12 of the substrate 10. The reflective layer 40 includes a reflective surface 41 and a reflective rear surface 42 opposite the reflective surface 41. The reflective surface 41 faces the same direction as the substrate front surface 21. The reflective rear surface 42 faces the same direction as the substrate rear surface 22. The reflective layer 40 has a thickness that allows it to reflect electromagnetic waves generated or detected by the second active elements 171b, 172b and the first active elements 171a, 172a. The reflective layer 40 may be arranged to overlap the slots 121, 122 in a plan view. In one example, the reflective layer 40 is formed to cover the entire rear surface 12 of the substrate 10.

[0054] The reflective layer 40 is composed of a metal layer provided on the rear surface 12 of the substrate 10. The reflective layer 40 is formed of at least one metal material selected from the group consisting of Au, Ag, Al, Cu, Ti, TiN, and Pt. It can also be said that the reflective layer 40 contains at least one of Au, Ag, Al, Cu, Ti, and Pt. In one example, the reflective layer 40 is formed of a material containing Au. The reflective layer 40 may be formed of the same material as the conductive layer 110. The reflective layer 40 may be formed by, for example, sputtering. The reflective layer 40 may be formed of a laminate structure of multiple metal layers.

[0055] (Details of the first active element and the second active element) Fig. 5 is a schematic plan view enlarging a portion of the terahertz device 100 in Fig. 1, showing the arrangement of the second active element 171b. Fig. 6 is a schematic plan view enlarging a portion of the terahertz device 100 in Fig. 1, showing the arrangement of the first active element 171a. Fig. 7 is a schematic cross-sectional view showing the second active element 171b, the first active element 171a, and their surroundings.

[0056] An example of a configuration for realizing the first active element 171 a and the second active element 171 b will be described. As shown in Fig. 7, the first active element 171 a and the second active element 171 b are provided between the first electrode 141 and the semiconductor substrate 20 in the Z-axis direction.

[0057] A semiconductor layer 71a is provided on the substrate surface 21 of the semiconductor substrate 20. In one example, the semiconductor layer 71a has a rectangular shape in a plan view. The semiconductor layer 71a is formed of, for example, GaInAs. The semiconductor layer 71a is heavily doped with n-type impurities. A GaInAs layer 72a is stacked on 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 the n-type impurity concentration of the semiconductor layer 71a. A GaInAs layer 73a is stacked on the GaInAs layer 72a. The GaInAs layer 73a is not doped with impurities.

[0058] An AlAs layer 74a is stacked on the GaInAs layer 73a. An InGaAs layer 75 is stacked on the AlAs layer 74a. The InGaAs layer 75 is not doped with impurities. An AlAs layer 74b is stacked on the InGaAs layer 75. The AlAs layer 74a, the InGaAs layer 75, and the AlAs layer 74b form a resonant tunneling section.

[0059] An undoped GaInAs layer 73b is stacked on the AlAs layer 74b. An n-type impurity-doped GaInAs layer 72b is stacked on the GaInAs layer 73b. A highly doped GaInAs layer 71b is stacked on the GaInAs layer 72b. Therefore, the n-type impurity concentration of the GaInAs layer 71b is higher than that of the GaInAs layer 72b.

[0060] The specific configuration of the first active element 171 a and the second active element 171 b can be changed as desired as long as they are capable of generating (or detecting, or both) electromagnetic waves. In other words, the first active element 171 a and the second active element 171 b may be any element that performs at least one of oscillation and detection of electromagnetic waves in the terahertz band.

[0061] For the second active element 171b, the connection portion 150b extending from the second electrode 150 extends toward the semiconductor layer 71a and is electrically connected to the semiconductor layer 71a. The connection portion 141b extending from the first electrode 141 contacts the upper surface of the GaInAs layer 71b and is electrically connected to the GaInAs layer 71b. In this manner, the second active element 171b is connected between the second electrode 150 and the first electrode 141.

[0062] For the first active element 171a, the connection portion 141a extending from the first electrode 141 contacts the upper surface of the GaInAs layer 71b and is electrically connected to the GaInAs layer 71b. The connection portion 150a extending from the second electrode 150 extends toward the semiconductor layer 71a and is electrically connected to the semiconductor layer 71a. In this way, the first active element 171a is connected between the first electrode 141 and the second electrode 150.

[0063] 1, 3, and 4 is configured similarly to the first active element 171a shown in Figures 6 and 7, and is connected to the first electrode 142 and the second electrode 150. The second active element 172b is configured similarly to the second active element 171b shown in Figures 5 and 7, and is connected to the first electrode 141 and the second electrode 150. For this reason, drawings and descriptions relating to the configurations of the first active element 172a and the second active element 172b will be omitted.

[0064] (Details of Resistance Element) Fig. 8 is a schematic plan view enlarging a part of the terahertz device 100 of Fig. 1, showing the arrangement and connection of the resistance element R2. Fig. 9 is a schematic cross-sectional view showing the resistance element R2 of Fig. 8 and its periphery.

[0065] 9, the resistor R2 is provided between the semiconductor substrate 20 and the second electrode 150. The resistor R2 is provided on the substrate surface 21 of the semiconductor substrate 20. In one example, the resistor R2 has a rectangular shape in a plan view. The resistor R2 is made of a semiconductor layer doped with a high concentration of n-type impurities. In one example, the semiconductor layer may be GaInAs.

[0066] The resistor R2 includes a first end R2a and a second end R2b opposite the first end. The first end R2a is electrically connected to the second electrode 150 through a via 64b formed on the resistor R2. The via 64b is formed of at least one metal material selected from the group consisting of Au, Ag, Al, Cu, Ti, TiN, and Pt. It can also be said that the via 64b includes at least one of Au, Ag, Al, Cu, Ti, and Pt. In one example, the via 64b is formed of a material including Au.

[0067] The second end R2b of the resistor R2 is connected to the lower wiring 61b. The lower wiring 61b is disposed within the insulating layer 30 in the Z-axis direction. The lower wiring 61b can be said to be disposed between the insulating front surface 31 and the insulating back surface 32 in the Z-axis direction. In one example, the insulating layer 30 may include a first insulating film formed on the semiconductor substrate 20 and a second insulating film formed on the first insulating film. The first insulating film may have the same thickness as the resistor R2, for example. The lower wiring 61b can be formed on the first insulating film. The insulating layer 30 may include three or more insulating films. The lower wiring 61b is formed of at least one metal material selected from the group consisting of Au, Ag, Al, Cu, Ti, TiN, and Pt. The lower wiring 61b can also be said to include at least one of Au, Ag, Al, Cu, Ti, and Pt. In one example, the lower wiring 61b is formed of a material containing Au.

[0068] 8, the lower wiring 61b is electrically connected to the first electrode 141 by the via 64. In this manner, the resistive element R2 is connected between the first electrode 141 and the second electrode 150.

[0069] 1 , the resistor element R1 is electrically connected to the first electrode 141 by the lower wiring 61 and the via 63. The resistor element R1 is also electrically connected to the second electrode 150 by the via 63b. In this manner, the resistor element R1 is connected between the first electrode 141 and the second electrode 150. The resistor elements R1 and R2 for the first electrode 142 are connected in the same way as the resistor elements R1 and R2 for the first electrode 141.

[0070] (Operation) Next, the operation of the terahertz device 100 of the first embodiment will be described. The slots 121 and 122 are formed in an annular shape. The conductive layer 110 includes first electrodes 141 and 142 defined by the slots 121 and 122, a connection line 161 disposed within the connecting slits 131 a and 131 b and electrically connecting the first electrodes 141 and 142 located on the inside of two adjacent slots 121 and 122, and a second electrode 150 located outside the slots 121 and 122. The connecting slits 131 a and 131 b connect the slots 121 and 122 and are formed to insulate the connection line 161 from the second electrode 150. The active elements 171a, 171b, 172a, and 172b are provided for the first electrodes 141 and 142, respectively, and are arranged at positions sandwiching the first electrodes 141 and 142 with respect to the centers O1 and O2 of the slots 121 and 122 in a plan view seen from a direction perpendicular to the surface 11.

[0071] The terahertz device 100 of the first embodiment can be said to include two slot antennas 121R and 122R arranged in the X-axis direction. Therefore, the terahertz device 100 of the first embodiment can radiate higher output electromagnetic waves than, for example, a terahertz device including one active element or a terahertz device including one slot antenna. The terahertz device 100 of the first embodiment can achieve improved characteristics.

[0072] The first electrodes 141 and 142 constituting the two slot antennas 121R and 122R are electrically connected by a connection line 161. Therefore, the terahertz device 100 of the first embodiment can operate the two slot antennas 121R and 122R in synchronization. The terahertz device 100 of the first embodiment can radiate higher output electromagnetic waves than, for example, a terahertz device including one active element or a terahertz device including one slot antenna.

[0073] The first electrodes 141 and 142 separated by the slots 121 and 122 are electrically connected by the connection line 161. Therefore, the terahertz device 100 according to the first embodiment can align the directions of currents flowing through the first electrodes 141 and 142 separated by the two slots 121 and 122.

[0074] The length of the connection line 161 is adjusted so that the active element 171a in the slot 121 and the active element 172b in the slot 122 are in opposite phase. This allows the directions of the currents flowing through the first electrodes 141 and 142 to be aligned.

[0075] The resistive elements R1 and R2 are arranged on either side of the first electrodes 141 and 142. The resistive elements R1 and R2 are arranged symmetrically with respect to the centers O1 and O2 of the slots 121 and 122. The resistive elements R1 and R2 are connected in parallel to the active elements 171a, 171b, 172a, and 172b arranged in the slots 121 and 122. The resistive elements R1 and R2 suppress parasitic oscillation.

[0076] The resistive elements R1 and R2 may be connected to a virtual short point with respect to the first electrodes 141 and 142. Leakage of electromagnetic waves to the resistive elements R1 and R2, the lower wiring 61b connecting the resistive elements R1 and R2 to the first electrodes 141 and 142, and the via 64 can be suppressed.

[0077] The connection wirings 51 and 52 connecting the first electrode pads 181 and 182 to the first electrodes 141 and 142 may be connected to virtual short points with respect to the first electrodes 141 and 142. This makes it possible to suppress leakage of electromagnetic waves to the connection wirings 51 and 52.

[0078] (Effects) As described above, the first embodiment provides the following effects: (1-1) The terahertz device 100 includes a substrate 10 including a front surface 11 and a back surface 12, a conductive layer 110 formed on the front surface 11, slots 121 and 122 formed in the conductive layer 110, connecting slits 131 a and 131 b formed in the conductive layer 110, and active elements 171 a, 171 b, 172 a, and 172 b provided in the slots 121 and 122.

[0079] The slots 121 and 122 are formed in an annular shape. The conductive layer 110 includes first electrodes 141 and 142 defined by the slots 121 and 122, connection lines 161 disposed in the connecting slits 131 a and 131 b and electrically connecting the first electrodes 141 and 142 located on the inside of two adjacent slots 121 and 122, and a second electrode 150 located outside the slots 121 and 122.

[0080] The connecting slits 131a and 131b connect the slots 121 and 122 and are formed to insulate the connection line 161 from the second electrode 150. The active elements 171a, 171b, 172a, and 172b are provided for the first electrodes 141 and 142, respectively, and are arranged at positions sandwiching the first electrodes 141 and 142 with respect to the centers O1 and O2 of the slots 121 and 122 in a plan view seen from a direction perpendicular to the surface 11.

[0081] The terahertz device 100 of the first embodiment can radiate electromagnetic waves with a higher output power than, for example, a terahertz device including one active element or a terahertz device including one slot antenna. The terahertz device 100 of the first embodiment can achieve improved characteristics.

[0082] (1-2) The first electrodes 141, 142 separated by the slots 121, 122 are electrically connected by the connection line 161. Therefore, the terahertz device 100 of the first embodiment can align the direction of the current flowing through the first electrodes 141, 142 separated by the two slots 121, 122. Therefore, the terahertz device 100 of the first embodiment can increase the output of the radiated electromagnetic waves.

[0083] (1-3) The length of the connection line 161 is adjusted so that the active element 171a in the slot 121 and the active element 172b in the slot 122 are in opposite phase. This prevents the electromagnetic waves from canceling each other out due to a phase shift. Therefore, the terahertz device 100 of the first embodiment can radiate high-power electromagnetic waves.

[0084] (1-4) The resistor elements R1 and R2 are arranged on either side of the first electrodes 141 and 142. The resistor elements R1 and R2 are arranged symmetrically with respect to the centers O1 and O2 of the slots 121 and 122. The resistor elements R1 and R2 are connected in parallel to the active elements 171a, 171b, 172a, and 172b arranged in the slots 121 and 122. The resistor elements R1 and R2 suppress parasitic oscillation. The resistor elements R1 and R2 can stabilize the oscillation in the active elements 171a, 171b, 172a, and 172b.

[0085] (1-5) The resistive elements R1 and R2 may be connected to a virtual short point with respect to the first electrodes 141 and 142. This can suppress leakage of electromagnetic waves to the resistive elements R1 and R2, the lower wiring 61b connecting the resistive elements R1 and R2 to the first electrodes 141 and 142, and the via 64. This allows the terahertz device 100 to efficiently radiate electromagnetic waves.

[0086] (1-6) The connection wirings 51 and 52 connecting the first electrode pads 181 and 182 to the first electrodes 141 and 142 may be connected to virtual short points with respect to the first electrodes 141 and 142. This can suppress leakage of electromagnetic waves to the connection wirings 51 and 52. This allows the terahertz device 100 to efficiently radiate electromagnetic waves.

[0087] Second Embodiment A terahertz device 200 according to a second embodiment will be described with reference to Fig. 10 and Fig. 11. In the second embodiment, parts common to those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and description thereof will be omitted.

[0088] The terahertz device 200 of the second embodiment differs from the terahertz device 100 of the first embodiment mainly in that it includes three slots 121, 122, and 123, and connecting slits 131 a, 131 b, 132 a, and 132 b that connect the slots 121, 122, and 123. Therefore, the differences will be mainly described for the second embodiment.

[0089] Fig. 10 is a schematic plan view of an exemplary terahertz device 200 according to the second embodiment. Fig. 11 is a schematic plan view showing an enlarged view of a portion relating to slots 121, 122, and 123 in Fig. 10.

[0090] (Slots, Connecting Slits) The terahertz device 200 of the second embodiment may include three slots 121, 122, and 123 formed in the conductive layer 210. The three slots 121, 122, and 123 are arranged spaced apart from one another along the X-axis direction. The three slots 121, 122, and 123 are arranged side by side along the side surfaces 13 and 14 of the substrate 10. The arrangement direction of the three slots 121, 122, and 123 may be changed as appropriate. The three slots 121, 122, and 123 are formed in an annular shape. Each of the slots 121, 122, and 123 is formed in an open annular shape and includes a first end 121 a, 122 a, or 123 a and a second end 121 b, 122 b, or 123 b. The slots 121, 122, and 123 are formed such that the first ends 121a, 122a, and 123a and the second ends 121b, 122b, and 123b are aligned in the Y-axis direction.

[0091] (First Slot) The slot 121 is formed in an open annular shape. The slot 121 includes a first end 121a and a second end 121b. The first end 121a and the second end 121b may be spaced apart in the Y-axis direction, which is perpendicular to the X-axis direction. It can be said that the slot 121 is formed in an open annular shape with the first end 121a and the second end 121b spaced apart in the Y-axis direction.

[0092] (Third Slot) The slot 122 is formed in an open annular shape. The slot 122 includes a first end 122a and a second end 122b. The first end 122a and the second end 122b may be spaced apart in the Y-axis direction, which is perpendicular to the X-axis direction. It can be said that the slot 122 is formed in an open annular shape with the first end 122a and the second end 122b spaced apart in the Y-axis direction.

[0093] (Second Slot) The slot 123 includes a first part 221 and a second part 222 formed in a semicircular shape. The first part 221 and the second part 222 are arranged to be spaced apart in the Y axis direction. The first part 221 is formed in a semicircular shape that opens toward the second part 222. The second part 222 is formed in a semicircular shape that opens toward the first part 221. It can be said that the slot 123 is formed in an annular shape that is open on both sides in the X axis direction by the first part 221 and the second part 222.

[0094] The first part 221 includes a first end 123a of the slot 123 and a third end 123c opposite the first end 123a. The first end 123a of the first part 221 is spaced apart in the X-axis direction from the first end 121a of the slot 121. It can be said that the first part 221 includes the first end 123a spaced apart in the X-axis direction from the first end 121a of the slot 121. The third end 123c of the first part 221 is spaced apart in the X-axis direction from the first end 122a of the slot 122. It can be said that the first part 221 includes the third end 123c spaced apart in the X-axis direction from the first end 122a of the slot 122.

[0095] The second part 222 includes a second end 123b of the slot 123 and a fourth end 123d opposite the second end 123b. The second end 123b of the second part 222 is spaced apart in the X-axis direction from the second end 121b of the slot 121. It can be said that the second part 222 includes the second end 123b spaced apart in the X-axis direction from the second end 121b of the slot 121. The fourth end 123d of the second part 222 is spaced apart in the X-axis direction from the second end 122b of the slot 122. It can be said that the second part 222 includes the fourth end 123d spaced apart in the X-axis direction from the second end 122b of the slot 122.

[0096] The first part 221 and the second part 222 may have the same shape. The lengths of the first part 221 and the second part 222 in the circumferential direction of the slot 123 are equal. The first part 221 and the second part 222 may be positioned symmetrically with respect to the center O3 of the slot 123. Therefore, the first end 123a of the first part 221 and the fourth end 123d of the second part 222 can be said to be located on opposite sides of the center O3 of the slot 123. The first end 123a of the first part 221 and the fourth end 123d of the second part 222 can be said to be located on a straight line passing through the center O3 of the slot 123. Furthermore, the third end 123c of the first part 221 and the second end 123b of the second part 222 can be said to be located on opposite sides of the center O3 of the slot 123. It can be said that the third end 123c of the first part 221 and the second end 123b of the second part 222 are disposed on a straight line passing through the center O3 of the slot 123. It can also be said that the slot 123 includes two ends aligned in the Y-axis direction, one on each side in the X-axis direction.

[0097] It can be said that slot 123, which is located in the center in the X-axis direction, is formed into a ring shape that is open on both sides in the X-axis direction by first part 221 and second part 222. It can be said that this slot 123 includes, in the X-axis direction, first end 123a and second end 123b facing slot 121, and third end 123c and fourth end 123d facing slot 122.

[0098] (Connecting Slits) The terahertz device 200 includes four connecting slits 131a, 131b, 132a, and 132b formed in the conductive layer 210. Each of the connecting slits 131a, 131b, 132a, and 132b is formed to extend in the X-axis direction in which the slots 121, 123, and 122 are aligned. The connecting slit 131a connects the first end 121a of the slot 121 to the first end 123a of the slot 123. The connecting slit 131b connects the second end 121b of the slot 121 to the second end 123b of the slot 123. The connecting slit 132a connects the third end 123c of the slot 123 to the first end 122a of the slot 122. The connecting slit 132b connects the fourth end 123d of the slot 123 to the second end 122b of the slot 122.

[0099] In the second embodiment, when focusing on the two slots 121 and 123, the slot 121 corresponds to the "first slot," and the slot 123 corresponds to the "second slot." Furthermore, when focusing on the two slots 123 and 122, the third end 123c of the slot 123, which is connected to the first end 122a of the slot 122, can be seen as the first end of the slot 123 relative to the slot 122. Furthermore, the fourth end 123d of the slot 123, which is connected to the second end 122b of the slot 122, can be seen as the second end of the slot 123 relative to the slot 122. Therefore, it can be said that the slot 123 corresponds to the "first slot," and the slot 122 corresponds to the "second slot."

[0100] (First Electrode, Second Electrode) The conductive layer 210 includes first electrodes 141, 143, and 142 defined by slots 121, 123, and 122. In one example, the first electrodes 141, 143, and 142 are formed in a circular shape in a plan view. The first electrodes 141, 143, and 142 are arranged spaced apart from each other in the X-axis direction. The first electrodes 141, 143, and 142 can be said to be arranged side by side along the side surfaces 13 and 14 of the substrate 10.

[0101] (Connection Lines) The conductive layer 210 includes connection lines 161 arranged in the connection slits 131a and 131b, and connection lines 162 arranged in the connection slits 132a and 132b.

[0102] The connection line 161 extends in the X-axis direction along the connecting slits 131a and 131b. A first end of the connection line 161 is electrically connected to the first electrode 141, and a second end of the connection line 161 is electrically connected to the first electrode 143. It can be said that the connection line 161 electrically connects the first electrodes 141 and 143 located inside two slots 121 and 123 adjacent to each other in the X-axis direction. It can be said that the connecting slits 131a and 131b are formed to insulate the connection line 161 from the second electrode 150. The connection line 161, which is insulated from the second electrode 150 by the connecting slits 131a and 131b, may be a coplanar waveguide (CPW).

[0103] The connection line 162 extends in the X-axis direction along the connecting slits 132a and 132b. A first end of the connection line 162 is electrically connected to the first electrode 143, and a second end of the connection line 162 is electrically connected to the first electrode 142. It can be said that the connection line 162 electrically connects the first electrodes 143 and 142 located inside two slots 123 and 122 adjacent to each other in the X-axis direction. It can be said that the connecting slits 132a and 132b are formed to insulate the connection line 162 from the second electrode 150. The connection line 162, which is insulated from the second electrode 150 by the connecting slits 132a and 132b, may be a coplanar waveguide (CPW).

[0104] In the terahertz device 200 of the second embodiment, it is preferable that the directions of currents flowing through the first electrodes 141, 143, and 142 partitioned by the three slots 121, 123, and 122 are the same. The length of the connection line 161 may be adjusted so that the active element 171a in the slot 121 and the active element 173b in the slot 123 are in opposite phase. The length of the connection line 162 may be adjusted so that the active element 173a in the slot 123 and the active element 172b in the slot 122 are in opposite phase. The lengths of the connection lines 161 and 162 may be (2n-1) / 2 (n: an integer greater than or equal to 1) of the effective wavelength λg of the terahertz device 200 or a value close to that. In one example, the length may be 1 / 2 (=λg / 2) of the effective wavelength λg of the terahertz device 200. It can be said that the connection line 161 is set so that the currents flowing in the same direction through the two connected first electrodes 141 and 143. It can be said that the connection line 162 is set so that the currents flowing in the same direction through the two connected first electrodes 143 and 142.

[0105] (Active Elements) The terahertz device 200 includes active elements 171a, 171b, 173a, 173b, 172a, and 172b.

[0106] Active elements 171a and 171b are disposed in slot 121. Active elements 172a and 172b are disposed in slot 122. Active elements 173a and 173b are disposed in slot 123. Active elements 173a and 173b are disposed within slot 123 at positions sandwiching first electrode 143 with respect to center O3 of slot 123. Active element 173a is disposed at third end 123c of first part 221. Active element 173b is disposed at second end 123b of second part 222. Second end 123b of second part 222 can be considered the second end of slot 123. Therefore, active element 173b can be considered to be disposed at the second end of slot 123. Active element 173b can be considered to correspond to a "third active element" disposed at the second end of slot 123, which is the second slot with respect to slot 121. The active element 173a can be said to correspond to a "fourth active element" that is arranged at a position opposite to the second end with respect to the center O3 of the slot 123.

[0107] Furthermore, it can be said that active element 173a is disposed at the first end of slot 123, which is the first slot, relative to slot 122, which is the second slot. Therefore, it can be said that active element 173a corresponds to the "first active element" in relation to slot 122. And active element 173b corresponds to the "second active element" in relation to slot 122. And active elements 172a and 172b of slot 122 correspond to the "fourth active element" and "third active element" in relation to slot 123.

[0108] Like the active elements 171a and 171b, the active elements 173a and 173b may be, for example, RTDs. The active elements 173a and 173b may be diodes or transistors other than RTDs. Examples of other active elements include TUNNETT diodes, IMPATT diodes, GaAs-based FETs, GaN-based FETs, HEMTs, HBTs, and CMOSFETs.

[0109] The end face of the conductive layer 210 facing the slot 121 in which the active elements 171a and 171b are arranged, i.e., the first electrode 141, and the portion of the second electrode 150 surrounding the first electrode 141, constitutes the slot antenna 121R. The end face of the conductive layer 210 facing the slot 122 in which the active elements 172a and 172b are arranged, i.e., the first electrode 142, and the portion of the second electrode 150 surrounding the first electrode 142, constitutes the slot antenna 122R. The end face of the conductive layer 210 facing the slot 123 in which the active elements 173a and 173b are arranged, i.e., the first electrode 141, and the portion of the second electrode 150 surrounding the first electrode 141, constitutes the slot antenna 123R.

[0110] The terahertz device 200 of the second embodiment can be said to include three slot antennas 121R, 123R, and 122R arranged in the X-axis direction. The first electrodes 141, 143, and 142 constituting the three slot antennas 121R, 123R, and 122R are electrically connected by connection lines 161 and 162. Therefore, the terahertz device 200 of the second embodiment can operate the three slot antennas 121R, 123R, and 122R in synchronization. The terahertz device 200 of the second embodiment can radiate higher output electromagnetic waves than, for example, a terahertz device including one active element or a terahertz device including one slot antenna.

[0111] 10 and 11 , the conductive layer 210 includes three first electrode pads 181, 183, and 182. The three first electrode pads 181, 183, and 182 are provided corresponding to the three first electrodes 141, 143, and 142. The number of first electrode pads may be changed as appropriate.

[0112] The first electrodes 141, 143, and 142 are disposed apart from the second electrode 150. The second electrode 150 includes recesses 1551, 1553, and 1552 recessed from the second side 152 toward the first electrodes 141, 143, and 142. The first electrode pads 181, 183, and 182 are disposed in the recesses 1551, 1553, and 1552, respectively.

[0113] 11 , the first electrode pads 181, 183, and 182 are electrically connected to the first electrodes 141, 143, and 142 via connection wirings 51, 53, and 52. The connection wiring 53 has a configuration similar to the connection wirings 51 and 52, and may include a lower wiring 61 and vias 62 and 63. The lower wiring 61 of the connection wiring 53 is electrically connected to the first electrode pad 183 via the via 62. In addition, the lower wiring 61 of the connection wiring 53 is electrically connected to the first electrode 143 via the via 63.

[0114] The second electrode pads 181b, 183b, and 182b are set as regions on the opposite side of the first electrodes 141, 143, and 142 from the first electrode pads 181, 183, and 182. The second electrode pads 181b, 183b, and 182b are set along the first side 151 of the second electrode 150 and spaced apart in the X-axis direction.

[0115] (Resistance Element) The terahertz device 200 may include resistance elements R1 and R2 connected to the first electrodes 141, 143, and 142, respectively. The first electrode 143 is connected to a first end of the resistance element R1 by the lower wiring 61 of the connection wiring 53, and a second end of the resistance element R1 is electrically connected to the second electrode 150 by a via 63b. Furthermore, the first electrode 143 is connected to a first end of the resistance element R2 by the via 64 and the lower wiring 61b, and a second end of the resistance element R2 is electrically connected to the second electrode 150 by a via 64b.

[0116] (Effects) As described above, the second embodiment provides the following effects: (2-1) The terahertz device 200 of the second embodiment can provide the same effects as the terahertz device 100 of the first embodiment.

[0117] (2-2) The terahertz device 200 of the second embodiment includes three slots 121, 123, and 122, and active elements 171a, 171b, 173a, 173b, 172a, and 172b arranged in the slots 121, 123, and 122. Therefore, the terahertz device 200 of the second embodiment can achieve higher output power than the terahertz device 100 of the first embodiment.

[0118] (2-2) The first electrodes 141 and 143 separated by the slots 121 and 123 are electrically connected by the connection line 161. The first electrodes 143 and 142 separated by the slots 123 and 122 are electrically connected by the connection line 162. Therefore, the terahertz device 200 of the second embodiment can align the directions of currents flowing through the first electrodes 141, 143, and 142 separated by the three slots 121, 123, and 122. Therefore, the terahertz device 200 of the second embodiment can radiate high-power electromagnetic waves.

[0119] (2-3) The length of the connection line 161 is adjusted so that the active element 171a in the slot 121 and the active element 173b in the slot 123 operate in opposite phases. The length of the connection line 162 is adjusted so that the active element 173a in the slot 123 and the active element 172b in the slot 122 operate in opposite phases. This makes it possible to prevent electromagnetic waves from canceling each other out due to a phase shift. Therefore, the terahertz device 200 of the second embodiment can radiate electromagnetic waves with a high output.

[0120] Third Embodiment A terahertz device 300 according to a third embodiment will be described with reference to Fig. 12. In the third embodiment, parts common to those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and description thereof will be omitted.

[0121] The terahertz device 300 of the third embodiment differs from the terahertz device 100 of the first embodiment mainly in the arrangement of the two slots 321 and 322 and the connecting slits 341 a, 341 b, 342 a, and 342 b that connect the slots 321 and 322. Therefore, the third embodiment will mainly be described with respect to the differences.

[0122] (Schematic configuration of terahertz device) Fig. 12 is a schematic plan view of an exemplary terahertz device 300 according to the third embodiment. As shown in Fig. 12, the terahertz device 300 includes a substrate 10. The substrate 10 may be formed in a rectangular shape in which the length in the Y-axis direction is longer than the length in the X-axis direction.

[0123] (Slots, Connecting Slits) The terahertz device 300 of the third embodiment may include two slots 321, 322 formed in the conductive layer 301. The two slots 321, 322 are arranged spaced apart from each other along the Y-axis direction. The two slots 321, 322 are arranged side by side along the side surfaces 15, 16 of the substrate 10. The arrangement direction of the two slots 321, 322 may be changed as appropriate. The two slots 321, 322 are formed in an annular shape. Each slot 321, 322 is formed in an open annular shape and includes first ends 321 a, 322 a and second ends 321 b, 322 b. Each slot 321, 322 is formed such that the first ends 321 a, 322 a and the second ends 321 b, 322 b are aligned in the Y-axis direction.

[0124] (First Slot) The slot 321 includes a first part 331a and a second part 331b formed in a semicircular shape. The first part 331a and the second part 331b are arranged to be spaced apart in the Y axis direction. The first part 331a is arranged on the opposite side of the slot 322 from the second part 331b. The first part 331a is formed in a semicircular shape that opens toward the second part 331b. The second part 331b is formed in a semicircular shape that opens toward the first part 331a. It can be said that the slot 321 is formed in a ring shape that is open on both sides in the X axis direction by the first part 331a and the second part 331b.

[0125] The first part 331a includes a first end 321a of the slot 321 and a third end 321c opposite the first end 321a. The second part 331b includes a second end 321b on the slot 321 side and a fourth end 321d opposite the second end 321b. The first part 331a and the second part 331b may have the same shape. The lengths of the first part 331a and the second part 331b in the circumferential direction of the slot 321 are equal. The first part 331a and the second part 331b may be positioned symmetrically with respect to the center O1 of the slot 321. Therefore, the first end 321a of the first part 331a and the fourth end 321d of the second part 331b are positioned opposite each other with respect to the center O1 of the slot 321. It can be said that the first end 321a of the first part 331a and the fourth end 321d of the second part 331b are arranged on a straight line passing through the center O1 of the slot 321. It can also be said that the third end 321c of the first part 331a and the second end 321b of the second part 331b are located on opposite sides of the center O1 of the slot 321. It can also be said that the third end 321c of the first part 331a and the second end 321b of the second part 331b are arranged on a straight line passing through the center O1 of the slot 321. It can also be said that the slot 321 includes two ends, one on each side in the X-axis direction and the other aligned in the Y-axis direction.

[0126] (Second Slot) The slot 322 includes a third part 332a and a fourth part 332b formed in a semicircular shape. The third part 332a and the fourth part 332b are spaced apart in the Y axis direction. The third part 332a is located on the opposite side of the fourth part 332b from the second part 331b of the slot 321. The third part 332a is formed in a semicircular shape that opens toward the fourth part 332b. The fourth part 332b is formed in a semicircular shape that opens toward the third part 332a. It can be said that the slot 322 is formed in a ring shape that is open on both sides in the X axis direction by the third part 332a and the fourth part 332b.

[0127] The third part 332a includes a first end 322a of the slot 322 and a third end 322c opposite the first end 322a. The fourth part 332b includes a second end 322b of the slot 322 and a fourth end 322d opposite the second end 322b. The third part 332a and the fourth part 332b may have the same shape. The lengths of the third part 332a and the fourth part 332b in the circumferential direction of the slot 322 are equal. The third part 332a and the fourth part 332b may be positioned symmetrically with respect to the center O2 of the slot 322. Therefore, the first end 322a of the third part 332a and the fourth end 322d of the fourth part 332b are positioned opposite each other with respect to the center O2 of the slot 322. The first end 322a of the third part 332a and the fourth end 322d of the fourth part 332b can be said to be disposed on a straight line passing through the center O2 of the slot 322. The third end 322c of the third part 332a and the second end 322b of the fourth part 332b can be said to be located on opposite sides of the center O2 of the slot 322. The third end 322c of the third part 332a and the second end 322b of the fourth part 332b can be said to be disposed on a straight line passing through the center O2 of the slot 322. The slot 322 can be said to include two ends aligned in the Y-axis direction, one on each side of the X-axis direction.

[0128] The slots 321 and 322 are formed in an annular shape that is open on both sides in the X-axis direction. The slots 321 and 322 can be said to be arranged spaced apart in the Y-axis direction that is perpendicular to the X-axis direction in which the open portions face.

[0129] (Connecting Slits) The terahertz device 300 includes four connecting slits 341 a , 341 b , 342 a , and 342 b formed in the conductive layer 301 .

[0130] When viewed from the Y-axis direction, the connecting slits 341a, 341b, 342a, and 342b are arranged so as to protrude in the X-axis direction from the slots 321 and 322. The connecting slits 341a, 341b, 342a, and 342b connect the slots 321 and 322 to each other.

[0131] The first connecting slit 341a connects the first end 321a of the first part 331a to the first end 322a of the third part 332a. It can be said that the first connecting slit 341a connects the first end 321a of the slot 321 to the first end 322a of the slot 322. The second connecting slit 341b connects the second end 321b of the second part 331b to the second end 322b of the fourth part 332b. It can be said that the second connecting slit 341b connects the second end 321b of the slot 321 to the second end 322b of the slot 322. The connecting slits 341a and 341b are formed in a semicircular shape.

[0132] The third connecting slit 342a connects the third end 321c of the first part 331a to the third end 322c of the third part 332a. It can be said that the third connecting slit 342a connects the third end 321c of the slot 321 to the third end 322c of the slot 322. The fourth connecting slit 342b connects the fourth end 321d of the second part 331b to the fourth end 322d of the fourth part 332b. It can be said that the fourth connecting slit 342b connects the fourth end 321d of the slot 321 to the fourth end 322d of the slot 322. The connecting slits 342a and 342b are formed in a semicircular shape.

[0133] (First Electrode, Second Electrode) The conductive layer 301 includes first electrodes 141, 142 that are partitioned by slots 321, 322. In one example, the first electrodes 141, 142 are formed in a circular shape in a plan view. The first electrodes 141, 142 are disposed spaced apart from each other in the Y-axis direction.

[0134] The second connecting slit 341b connects the second end 321b of the second part 331b to the second end 322b of the fourth part 332b. The fourth connecting slit 342b connects the fourth end 321d of the second part 331b to the fourth end 322d of the fourth part 332b. Therefore, the second part 331b, the fourth part 332b, and the connecting slits 341b and 342b define an electrode portion 302b in the conductive layer 301. The second electrode 150 includes a frame-shaped portion 302a that surrounds the slots 321 and 322 and the connecting slits 341a and 342a. The electrode portion 302b is electrically connected to the frame-shaped portion 302a by connection wirings 303a and 303b. The electrode portion 302b and the frame-shaped portion 302a constitute the second electrode 150.

[0135] The connection wirings 303a and 303b may, for example, include lower wiring, vias, etc. The lower wiring of the connection wiring 303a is formed so as to intersect with the connecting slits 341a and 341b and the connection line 361. The lower wiring of the connection wiring 303b is formed so as to intersect with the connecting slits 342a and 342b and the connection line 362. The connection wirings 303a and 303b may be formed so as to straddle the connecting slits 341a, 341b, 342a, 342b and the connection lines 361 and 362. For example, an insulating layer may be formed so as to partially cover the connecting slits 341a, 341b, 342a, 342b and the connection lines 361 and 362, and the connection wirings 303a and 303b that electrically connect the electrode portion 302b and the frame-shaped portion 302a that constitute the second electrode 150 may be formed on this insulating layer.

[0136] (Connection Line) The conductive layer 301 includes a connection line 361 arranged in the coupling slits 341 a and 341 b, and a connection line 362 arranged in the coupling slits 342 a and 342 b. In one example, the connection line 361 is formed in an arc shape along the coupling slits 341 a and 341 b. In one example, the connection line 362 is formed in an arc shape along the coupling slits 342 a and 342 b.

[0137] (Active Elements) The terahertz device 300 includes active elements 371a, 371b, 372a, and 372b. The active elements 371a and 371b are disposed in the slot 321. The active elements 371a and 371b are disposed in the slot 321 at positions sandwiching the first electrode 141 with respect to the center O1 of the slot 321. The active element 371a is disposed at the first end 321a of the first part 331a. The active element 371b is disposed at the fourth end 321d of the second part 331b. The first end 321a of the first part 331a and the fourth end 321d of the second part 331b are located on opposite sides of the center O1 of the slot 321. Therefore, it can be said that the active elements 371a and 371b are disposed in the slots 321 and 322 on a reference line passing through the center O1 of the slot 321.

[0138] The active elements 372a and 372b are disposed within the slot 322. The active elements 372a and 372b are disposed within the slot 322 at positions sandwiching the first electrode 142 with respect to the center O2 of the slot 322. The active element 372a is disposed at the second end 322b of the fourth part 332b. The active element 372b is disposed at the third end 322c of the third part 332a. The second end 322b of the fourth part 332b and the third end 322c of the third part 332a are located on opposite sides of the center O2 of the slot 322. Therefore, it can be said that the active elements 372a and 372b are disposed within the slots 321 and 322 on a reference line passing through the center O2 of the slot 322.

[0139] For example, the active elements 371 a, 371 b, 372 a, and 372 b may be RTDs. The active elements 371 a, 371 b, 372 a, and 372 b may be diodes or transistors other than RTDs. Examples of other active elements include TUNNETT diodes, IMPATT diodes, GaAs-based FETs, GaN-based FETs, HEMTs, HBTs, and CMOSFETs.

[0140] The active elements 371a and 371b are connected in parallel to the first electrode 141 and the second electrode 150. The active elements 372a and 372b are connected in parallel to the first electrode 142 and the second electrode 150. The connection lines 361 and 362 may be formed so that the active elements 371a and 372a, and the active elements 371b and 372b operate in phase with each other.

[0141] The end face of the conductive layer 301 facing the slot 321 in which the active elements 371a and 371b are arranged, i.e., the first electrode 141, and the portion of the second electrode 150 surrounding the first electrode 141, constitutes a slot antenna 321R. The end face of the conductive layer 301 facing the slot 322 in which the active elements 372a and 372b are arranged, i.e., the first electrode 142, and the portion of the second electrode 150 surrounding the first electrode 142, constitutes a slot antenna 322R.

[0142] The terahertz device 300 of the third embodiment can be said to include two slot antennas 321R, 322R arranged in the Y-axis direction. The first electrodes 141, 142 constituting the two slot antennas 321R, 322R are electrically connected by connection lines 361, 362. Therefore, the terahertz device 300 of the third embodiment can operate the two slot antennas 321R, 322R in synchronization. The terahertz device 300 of the third embodiment can radiate higher output electromagnetic waves than, for example, a terahertz device including one active element or a terahertz device including one slot antenna.

[0143] (First Electrode Pads, Second Electrode Pads) The conductive layer 301 includes two first electrode pads 181 and 182. The two first electrode pads 181 and 182 are provided corresponding to the two first electrodes 141 and 142. The number of first electrode pads 181 and 182 may be changed as appropriate.

[0144] The first electrode pads 181 and 182 are disposed apart from the second electrode 150. The second electrode 150 includes a recess 1551 recessed from the second side 152 toward the first electrode 141, and a recess 1552 recessed from the first side 151 toward the first electrode 142. The first electrode pads 181 and 182 are disposed in the recesses 1551 and 1552, respectively.

[0145] The second electrode pads 181b, 182b are set as regions aligned in the X-axis direction with respect to the first electrode pads 181, 182. The second electrode pad 181b is set alongside the first electrode pad 181 on the second side 152 of the second electrode 150. The second electrode pad 182b is set alongside the first electrode pad 182 on the first side 151 of the second electrode 150. The number of second electrode pads 181b, 182b may be changed as appropriate.

[0146] (Operation) Next, the operation of the terahertz device 300 of the third embodiment will be described. The lengths of the connection lines 361 and 362 may be adjusted so that the active element 371a in the slot 321 and the active element 372a in the slot 322, and the active element 171b in the slot 321 and the active element 372b in the slot 322, operate in phase. The lengths of the connection lines 361 and 362 may be an integer multiple (=n×λg: n is an integer greater than or equal to 1) of the effective wavelength λg in the terahertz device 300, or a value close to that integer multiple. In one example, the lengths of the connection lines 361 and 362 may be equal to the effective wavelength λg in the terahertz device 300. It can be said that the connection lines 361 and 362 are set so that the currents flowing through the two first electrodes 141 and 142 they connect are in the same direction. Furthermore, the lengths of the connection lines 361 and 362 can be said to be set so that the active elements 371a and 371b and the active elements 372a and 372b located at both ends of the lines operate in phase.

[0147] (Effects) As described above, the third embodiment provides the following effects. (3-1) In the terahertz device 300 of the third embodiment, the annular slots 321, 322 that are open in the X-axis direction are arranged to be spaced apart from each other in the Y-axis direction. The first electrodes 141, 142 that are partitioned by the slots 321, 322 arranged in this manner are connected to each other by the connection lines 361, 362. The terahertz device 300 in which the slots 321, 322 and the first electrodes 141, 142 are arranged in this manner can achieve high output.

[0148] (3-2) The first electrodes 141, 142 are connected to each other by connection lines 361, 362. By connecting the first electrodes 141, 142 to each other in this manner, the active elements 371a, 371b, 372a, 372b arranged in the slots 321, 322 can be operated in synchronization, thereby achieving high output.

[0149] (3-3) The lengths of the connection lines 361 and 362 are adjusted so that the active elements 371a and 372a, and the active elements 371b and 372b are in phase with each other. This allows the directions of the currents flowing through the first electrodes 141 and 142 to be aligned. This allows the terahertz device 300 of the third embodiment to radiate high-power electromagnetic waves.

[0150] Fourth Embodiment A terahertz device 400 according to a fourth embodiment will be described with reference to Fig. 13. In the fourth embodiment, parts common to those in the third embodiment will be assigned the same reference numerals as those in the third embodiment, and descriptions thereof will be omitted.

[0151] The terahertz device 400 of the fourth embodiment differs from the terahertz device 300 of the third embodiment in the shapes of the coupling slits 441a, 441b, 442a, 442b and the connection lines 461, 462. Therefore, the fourth embodiment will be mainly described with respect to the differences from the third embodiment.

[0152] 13 is a schematic plan view of an exemplary terahertz device 400 according to the fourth embodiment. The terahertz device 400 of the fourth embodiment may include two slots 321 and 322 formed in a conductive layer 401, and connecting slits 441a, 441b, 442a, and 442b connecting the two slots 321 and 322. The connecting slits 441a, 441b, 442a, and 442b are formed in a substantially U-shape when viewed from the Z-axis direction. The connecting lines 461 and 462 are also formed in a substantially U-shape when viewed from the Z-axis direction.

[0153] The connecting slit 441a includes a first linear portion 441a1 and a second linear portion 441a2 extending along the X-axis direction, a third linear portion 441a3 extending along the Y-axis direction, a first connecting portion 441a4 connecting the first linear portion 441a1 and the third linear portion 441a3, and a second connecting portion 441a5 connecting the second linear portion 441a2 and the third linear portion 441a3. The first linear portion 441a1 is connected to the first end 321a of the first part 331a, and the second linear portion 441a2 is connected to the first end 322a of the third part 332a.

[0154] The connecting slit 441b includes a first linear portion 441b1 and a second linear portion 441b2 extending along the X-axis direction, a third linear portion 442b3 extending along the Y-axis direction, a first connecting portion 441b4 connecting the first linear portion 441b1 and the third linear portion 441b3, and a second connecting portion 441b5 connecting the second linear portion 441b2 and the third linear portion 441b3. The first linear portion 441b1 is connected to the second end 321b of the second part 331b, and the second linear portion 441b2 is connected to the second end 322b of the fourth part 332b.

[0155] The connecting slit 442a includes a first linear portion 442a1 and a second linear portion 442a2 extending along the X-axis direction, a third linear portion 442a3 extending along the Y-axis direction, a first connecting portion 442a4 connecting the first linear portion 442a1 and the third linear portion 442a3, and a second connecting portion 442a5 connecting the second linear portion 442a2 and the third linear portion 442a3. The first linear portion 442a1 is connected to the third end portion 321c of the first part 331a, and the second linear portion 442a2 is connected to the third end portion 322c of the third part 332a.

[0156] The connecting slit 442b includes a first linear portion 442b1 and a second linear portion 442b2 extending along the X-axis direction, a third linear portion 442b3 extending along the Y-axis direction, a first connecting portion 442b4 connecting the first linear portion 442b1 and the third linear portion 442b3, and a second connecting portion 442b5 connecting the second linear portion 442b2 and the third linear portion 442b3. The first linear portion 442b1 is connected to the fourth end 321d of the second part 331b, and the second linear portion 442b2 is connected to the fourth end 322d of the fourth part 332b.

[0157] The connection line 461 includes a first line 4611 and a second line 4612 extending along the X-axis direction, a third line 4613 extending along the Y-axis direction, a first connection portion 4614 connecting the first line 4611 and the third line 4613, and a second connection portion 4615 connecting the second line 4612 and the third line 4613.

[0158] The connection line 462 includes a first line 4621 and a second line 4622 extending along the X-axis direction, a third line 4623 extending along the Y-axis direction, a first connection portion 4624 connecting the first line 4621 and the third line 4623, and a second connection portion 4625 connecting the second line 4622 and the third line 4623.

[0159] (Effects) As described above, the fourth embodiment provides the following effects: (4-1) The terahertz device 400 of the fourth embodiment can provide the same effects as the terahertz device 300 of the third embodiment.

[0160] Fifth Embodiment A terahertz device 500 according to a fifth embodiment will be described with reference to Fig. 14. In the fifth embodiment, parts common to those in the third embodiment will be assigned the same reference numerals as those in the third embodiment, and descriptions thereof will be omitted.

[0161] The terahertz device 500 of the fifth embodiment differs from the terahertz device 300 of the third embodiment in the first electrode pad 181 and its connection. Therefore, the fifth embodiment will be mainly described with respect to the differences from the third embodiment.

[0162] 14 is a schematic plan view of an exemplary terahertz device 500 according to the fifth embodiment. As shown in FIG. 14 , the conductive layer 501 includes one first electrode pad 181 and one second electrode pad 181b for the two first electrodes 141 and 142.

[0163] The first electrode pad 181 is arranged alongside the first electrodes 141 and 142. The first electrode pad 181 is electrically connected to the first electrodes 141 and 142 by a connection wiring 510.

[0164] The connection wiring 510 may include a lower wiring 511 and vias 521, 522, 523, 524, and 525. The lower wiring 511 extends along the Y-axis direction. In one example, the lower wiring 511 extends from the first electrode pad 181 to the resistor element R1 connected to the first electrode 142.

[0165] The via 521 connects the lower wiring 511 and the first electrode pad 181. The vias 522 and 523 connect the lower wiring 511 and the first electrode 141. The vias 522 and 523 are arranged on either side of the center O1 of the slot 321. The vias 522 and 523 are connected to both ends of the first electrode 141 in the Y-axis direction.

[0166] The vias 524 and 525 connect the lower wiring 511 and the first electrode 142. The vias 524 and 525 are arranged on either side of the center O2 of the slot 322. The vias 524 and 525 are connected to both ends of the first electrode 142 in the Y-axis direction.

[0167] The lower wiring 511 may be used as wiring that connects the resistor elements R1 and R2 to the first electrodes 141 and 142. In the lower wiring 511, the wiring portion between the via 522 and the via 523 may be omitted. Also, in the lower wiring 511, the wiring portion between the via 524 and the via 525 may be omitted.

[0168] The second electrode pad 181b is set as a region aligned in the X-axis direction with respect to the first electrode pad 181. The second electrode pad 181b may be set along the first side 151 of the second electrode 150. The second electrode pad 181b may be set at the same position as the first electrode pad 181 in the X-axis direction on the first side 151 of the second electrode 150.

[0169] (Effects) As described above, the fifth embodiment provides the following effects: (5-1) The terahertz device 500 of the fifth embodiment can provide the same effects as the terahertz device 300 of the third embodiment.

[0170] (5-2) The terahertz device 500 of the fifth embodiment can simplify the connections for feeding power to the first electrode 141 and the second electrode 150. (Sixth Embodiment) A terahertz device 600 of a sixth embodiment will be described with reference to FIG.

[0171] In the sixth embodiment, parts common to the first to fifth embodiments are assigned the same reference numerals as those in the first to fifth embodiments, and descriptions thereof will be omitted. The terahertz device 600 of the sixth embodiment differs from the terahertz devices 100, 200, 300, 400, and 500 of the above embodiments mainly in that a plurality of slots are arranged in an array. Therefore, the sixth embodiment will be mainly described with respect to the differences from the first to fifth embodiments.

[0172] 15 is a schematic plan view of an exemplary terahertz device 600 according to the sixth embodiment. The terahertz device 600 of the sixth embodiment may include nine slots 611 to 613, 621 to 623, and 631 to 633 formed in a conductive layer 601. The slots 611 to 613, 621 to 623, and 631 to 633 are arranged at a distance from each other in the X-axis direction and the Y-axis direction. The slots 611 to 613, 621 to 623, and 631 to 633 are arranged in a so-called 3×3 array in the X-axis direction and the Y-axis direction.

[0173] (Slots) Each of the slots 611 to 613, 621 to 623, and 631 to 633 includes a first part 651 and a second part 652. The first part 651 and the second part 652 are formed in a semicircular shape. The first part 651 and the second part 652 are disposed spaced apart from each other in the Y-axis direction. The first part 651 is formed in a semicircular shape that opens toward the second part 652. The second part 652 is formed in a semicircular shape that opens toward the first part 651. It can be said that the slots 611 to 613, 621 to 623, and 631 to 633 are formed by the first part 651 and the second part 652 in the shape of an annulus that is open on both sides in the X-axis direction.

[0174] The first part 651 includes a first end 610a and a third end 610c opposite the first end 610a. The second part 652 includes a second end 610b and a fourth end 610d opposite the second end 610b. The first end 610a of the first part 651 and the second end 610b of the second part 652 are aligned in the Y axis direction and spaced apart from each other. The third end 610c of the first part 651 and the fourth end 610d of the second part 652 are aligned in the Y axis direction and spaced apart from each other.

[0175] (Connecting Slits) Adjacent slots 611 to 613, 621 to 623, and 631 to 633 in the X-axis direction are connected by connecting slits 661a and 661b. Connecting slit 661a connects two adjacent first parts 651 in the X-axis direction in slots 611 to 613, 621 to 623, and 631 to 633. Connecting slit 661b connects two adjacent second parts 652 in the X-axis direction in slots 611 to 613, 621 to 623, and 631 to 633. For example, the slots 611 and 612 adjacent in the X-axis direction will be described. Connecting slit 661a connects a first end 610a of the first part 651 in slot 611 to a third end 610c of the first part 651 in slot 612. Connecting slit 661b connects second end 610b of second part 652 of slot 611 to fourth end 610d of second part 652 of slot 612. Although slots 611 and 612 have been described above, the same applies to the other slots 612 and 613, slots 621 and 622, slots 622 and 623, slots 631 and 632, and slots 632 and 633.

[0176] Of the multiple slots 611 to 613, 621 to 623, and 631 to 633, the slots 613, 623, and 633 are slots located at one end in the X-axis direction and are spaced apart from one another in the Y-axis direction. These slots 613, 623, and 633 are also arranged along the side surface 16 of the substrate 10. Of these slots 613, 623, and 633 arranged in the Y-axis direction, the slots 613 and 633 located at both ends in the Y-axis direction are referred to as the first end slot 613 and the second end slot 633. In the Y-axis direction, the slot 623 between the first end slot 613 and the second end slot 633 is referred to as the intermediate slot 623. The terahertz device 600 of the sixth embodiment includes one intermediate slot 623 located between the first end slot 613 and the second end slot 633. The number of intermediate slots 623 may be changed as appropriate.

[0177] The first end slot 613, the second end slot 633, and the intermediate slot 623 are connected by connecting slits 671, 672, and 673. The connecting slit 671 connects the first end 610a of the first part 651 of the first end slot 613 to the second end 610b of the second part 652 of the second end slot 633. The connecting slit 671 has a shape in which two semicircular connecting portions 671a, 671b are connected in the Y-axis direction. The number of connecting portions varies depending on the number of slots arranged in the Y-axis direction.

[0178] The connecting slit 672 connects the second end 610b of the second part 652 of the first end slot 613 to the first end 610a of the first part 651 of the intermediate slot 623. The connecting slit 672 corresponds to a "first intermediate connecting slit." The connecting slit 673 connects the second end 610b of the second part 652 of the intermediate slot 623 to the first end 610a of the first part 651 of the second end slot 633. The connecting slit 673 corresponds to a "second intermediate connecting slit." The connecting slits 672 and 673 are formed in an arc shape.

[0179] Of the multiple slots 611 to 613, 621 to 623, and 631 to 633, the slots 611, 621, and 631 are slots arranged at the end opposite the slots 613, 623, and 633 in the X-axis direction, and are arranged spaced apart from each other in the Y-axis direction. Furthermore, these slots 611, 621, and 631 are arranged along the side surface 15 of the substrate 10. Of the slots 611, 621, and 631 arranged in the Y-axis direction, the slots 611 and 631 arranged at both ends in the Y-axis direction are referred to as first end slots 611 and second end slots 631. In the Y-axis direction, the slot 621 between the first end slot 611 and the second end slot 631 is referred to as an intermediate slot 621. The terahertz device 600 of the sixth embodiment includes one intermediate slot 621 arranged between the first end slot 611 and the second end slot 631. The number of intermediate slots 621 may be changed as appropriate.

[0180] The first end slot 611, the second end slot 631, and the intermediate slot 621 are connected by connecting slits 674, 675, and 676. The connecting slit 674 connects the third end 610c of the first part 651 of the first end slot 611 to the fourth end 610d of the second part 652 of the second end slot 631. The connecting slit 674 has a shape in which two arc-shaped connecting portions 674a, 674b are connected in the Y-axis direction. The number of connecting portions varies depending on the number of slots arranged in the Y direction.

[0181] The connecting slit 675 connects the fourth end 610d of the second part 652 of the first end slot 611 to the third end 610c of the first part 651 of the intermediate slot 621. The connecting slit 675 corresponds to the "third intermediate connecting slit." The connecting slit 676 connects the fourth end 610d of the second part 652 of the intermediate slot 621 to the third end 610c of the first part 651 of the second end slot 631. The connecting slit 676 corresponds to the "fourth intermediate connecting slit." The connecting slits 675, 676 are formed in an arc shape.

[0182] (First Electrode, Second Electrode) The conductive layer 601 includes first electrodes 141 defined by slots 611 to 613, 621 to 623, and 631 to 633. In one example, the first electrodes 141 are formed in a circular shape in a plan view. The first electrodes 141 are disposed spaced apart from each other in the X-axis direction and the Y-axis direction.

[0183] The second part 652 of the slots 611 to 613, the first part 651 of the slots 621 to 623, the connecting slit 661b between the slots 611 to 613, the connecting slit 661a between the slots 621 to 623, the connecting slit 672, and the connecting slit 675 define the first electrode portion 602b.

[0184] The second part 652 of the slots 621 to 623, the first part 651 of the slots 631 to 633, the connecting slit 661b between the slots 621 to 623, the connecting slit 661a between the slots 631 to 633, the connecting slit 673, and the connecting slit 676 define the second electrode portion 602c.

[0185] The second electrode 150 includes a frame-shaped portion 602a that surrounds the slots 611 to 613, 621 to 623, and 631 to 633. The first electrode portion 602b is electrically connected to the frame-shaped portion 602a by first connection wirings 603a and 603b. The second electrode portion 602c is electrically connected to the frame-shaped portion 602a by second connection wirings 604a and 604b. The first electrode portion 602b, the second electrode portion 602c, and the frame-shaped portion 602a constitute the second electrode 150.

[0186] The first connection wirings 603a and 603b may, for example, include lower wirings, vias, etc. The lower wiring of the first connection wiring 603a is formed to intersect with the connecting portion 671a of the connecting slit 671, the connecting slit 672, and the connecting line 682. The lower wiring of the first connection wiring 603b is formed to intersect with the connecting portion 674a of the connecting slit 674, the connecting slit 675, and the connecting line 684. The second connection wirings 604a and 604b may, for example, include lower wirings, vias, etc. The lower wiring of the second connection wiring 604a is formed to intersect with the connecting portion 671b of the connecting slit 671, the connecting slit 673, and the connecting line 683. The lower wiring of the second connection wiring 604b is formed to intersect with the connecting portion 674b of the connecting slit 674, the connecting slit 676, and the connecting line 685. The first connection wirings 603a and 603b may be formed so as to straddle the connection slits 671 (671a), 672, 674 (674a), and 675 and the connection lines 682 and 684. The second connection wirings 604a and 604b may be formed so as to straddle the connection slits 671 (671b), 673, 674 (674b), and 676 and the connection lines 683 and 685.

[0187] (Connection Line) The conductive layer 601 includes a connection line 681 that connects the first electrodes 141 of the slots 611 to 613, 621 to 623, and 631 to 633 that are arranged in the X-axis direction. The conductive layer 601 includes connection lines 682 and 683 that connect the slots 613, 623, and 633 that are arranged in the Y-axis direction, and connection lines 684 and 685 that connect the slots 611, 621, and 631.

[0188] (Active Element) The terahertz device 600 includes a first active element 691 and a second active element 692 disposed in the slots 611-613, 621-623, and 631-633.

[0189] The first active element 691 is disposed at the first end 610a of the first part 651 of each of the slots 611-613, 621-623, and 631-633. The second active element 692 is disposed at the fourth end 610d of the second part 652. The first end 610a of the first part 651 and the fourth end 610d of the second part 652 are located on opposite sides of the centers of the slots 611-613, 621-623, and 631-633. Therefore, it can be said that the first active element 691 and the second active element 692 are disposed within the slots 611-613, 621-623, and 631-633 on a reference line passing through the centers of the slots 611-613, 621-623, and 631-633.

[0190] For example, the first active element 691 and the second active element 692 may be an RTD. The first active element 691 and the second active element 692 may be a diode or a transistor other than an RTD. Examples of other active elements include a TUNNETT diode, an IMPATT diode, a GaAs-based FET, a GaN-based FET, a HEMT, an HBT, or a CMOSFET.

[0191] The first active element 691 and the second active element 692 are connected to the first electrode 141 and the second electrode 150 so as to be parallel to each other. (First Electrode Pad, Second Electrode Pad) The first electrode pad 181 is arranged alongside the first electrodes 141 of the slots 611, 621, and 631. The first electrode pad 181 is electrically connected to the first electrodes 141 by the connection wiring 51.

[0192] The first electrode pads 182 are arranged alongside the first electrodes 141 in the slots 612, 622, and 632. The first electrode pads 182 are electrically connected to the first electrodes 141 by the connection wiring 52.

[0193] The first electrode pads 183 are arranged alongside the first electrodes 141 in the slots 613, 623, and 633. The first electrode pads 183 are electrically connected to the first electrodes 141 by the connection wiring 53.

[0194] The second electrode pad 181b is set as a region aligned in the X-axis direction with respect to the first electrode pad 181. The second electrode pad 181b may be set along the first side 151 of the second electrode 150. The second electrode pad 181b may be set at the same position in the X-axis direction as any one of the first electrode pads 181, 182, and 183 on the first side 151 of the second electrode 150.

[0195] (Effects) As described above, the sixth embodiment provides the following effects: (6-1) The terahertz device 600 of the sixth embodiment can provide the same effects as the above-described embodiments.

[0196] (6-2) The terahertz device 600 of the sixth embodiment includes a first electrode 141 partitioned by array-arranged slots 611 to 613, 621 to 623, and 631 to 633, and a first active element 691 and a second active element 692 arranged in the slots 611 to 613, 621 to 623, and 631 to 633. This enables the terahertz device 600 to achieve a high output of electromagnetic waves.

[0197] Seventh Embodiment A terahertz device 700 according to a seventh embodiment will be described with reference to Fig. 16. In the seventh embodiment, parts common to those in the sixth embodiment will be assigned the same reference numerals as those in the sixth embodiment, and descriptions thereof will be omitted.

[0198] The terahertz device 700 of the seventh embodiment differs from the terahertz device 600 of the sixth embodiment mainly in the connecting slits corresponding to the arrangement of the slots 711 to 713, 721 to 723, 731 to 733, and 741 to 743. Therefore, the seventh embodiment will be mainly described with respect to the differences from the sixth embodiment.

[0199] (General Configuration of Terahertz Device) A terahertz device 700 according to the seventh embodiment includes slots 711 to 713, 721 to 723, 731 to 733, and 741 to 743. The slots 711 to 713, 721 to 723, 731 to 733, and 741 to 743 are arranged in a so-called 3×4 array in the X-axis direction and the Y-axis direction.

[0200] Each of the slots 711 to 713, 721 to 723, 731 to 733, and 741 to 743 includes a first part 751 and a second part 752. The first part 751 and the second part 752 are formed in the same manner as the first part 651 and the second part 652 of the sixth embodiment. Similarly to the first part 651 and the second part 652 of the sixth embodiment, the first part 751 and the second part 752 include a first end 710a, a second end 710b, a third end 710c, and a fourth end 710d.

[0201] The first parts 751 and second parts 752 of slots 711 to 713 in the seventh embodiment are connected by connecting slits 761a and 761b, as in the sixth embodiment. The first parts 751 and second parts 752 of slots 721 to 723 are connected by connecting slits 761a and 761b, as in the sixth embodiment. The first part 751 of slot 721 corresponds to the "fifth part," and the second part 752 of slot 721 corresponds to the "sixth part." The first parts 751 and second parts 752 of slots 731 to 733 are connected by connecting slits 761a and 761b, as in the sixth embodiment. The first part 751 of slot 731 corresponds to the "fifth part," and the second part 752 of slot 731 corresponds to the "sixth part." The first part 751 and the second part 752 of the slots 741 to 743 are connected by connecting slits 761a and 761b, as in the sixth embodiment. The first part 751 of the slot 741 corresponds to the "third part," and the second part 752 of the slot 741 corresponds to the "fourth part."

[0202] The first electrodes 141 in the slots 711 to 713 are connected by a connecting line 781. The first electrodes 141 in the slots 721 to 723 are connected by a connecting line 781. The first electrodes 141 in the slots 731 to 733 are connected by a connecting line 781. The first electrodes 141 in the slots 741 to 743 are connected by a connecting line 781.

[0203] Of the slots 713, 723, 733, and 743 arranged in the Y-axis direction, the slots 713 and 743 located at both ends in the Y-axis direction are referred to as first end slots 713 and second end slots 743. In the Y-axis direction, the slots 723 and 733 between the first end slot 713 and the second end slot 743 are referred to as intermediate slots 723 and 733. The terahertz device 700 of the seventh embodiment includes two intermediate slots 723 and 733 located between the first end slot 713 and the second end slot 743.

[0204] The first end slot 713, the second end slot 743, and the intermediate slots 723 and 733 are connected by connecting slits 771, 772, 773, and 774. The connecting slit 771 connects the first end 710a of the first part 751 of the first end slot 713 to the second end 710b of the second part 752 of the second end slot 743. The connecting slit 771 has a shape in which three semicircular connecting portions 771a, 771b, and 771c are connected in the Y-axis direction, corresponding to the number of slots arranged in the Y-axis direction.

[0205] The connecting slit 772 connects the second end 710b of the second part 752 of the first end slot 713 to the first end 710a of the first part 751 of the intermediate slot 723. The connecting slit 772 corresponds to the "first intermediate connecting slit." The connecting slit 773 connects the second end 710b of the second part 752 of the intermediate slot 723 to the first end 710a of the first part 751 of the intermediate slot 733. The connecting slit 773 corresponds to the "fifth intermediate connecting slit." The connecting slit 774 connects the second end 710b of the second part 752 of the intermediate slot 733 to the first end 710a of the first part 751 of the second end slot 743. The connecting slit 774 corresponds to the "second intermediate connecting slit." The connecting slits 772, 773, and 774 are formed in an arc shape.

[0206] Of the slots 711, 721, 731, and 741 arranged in the Y-axis direction, the slots 711 and 741 located at both ends in the Y-axis direction are referred to as first end slots 711 and second end slots 741. In the Y-axis direction, the slots 721 and 731 between the first end slot 711 and the second end slot 741 are referred to as intermediate slots 721 and 731. The terahertz device 700 of the seventh embodiment includes two intermediate slots 721 and 731 located between the first end slot 711 and the second end slot 741.

[0207] The first end slot 711, the second end slot 741, and the intermediate slots 721 and 731 are connected by connecting slits 775, 776, 777, and 778. The connecting slit 775 connects the third end 710c of the first part 751 of the first end slot 711 to the fourth end 710d of the second part 752 of the second end slot 741. The connecting slit 775 has a shape in which three semicircular connecting portions 775a, 775b, and 775c are connected in the Y-axis direction, corresponding to the number of slots arranged in the Y-axis direction.

[0208] The connecting slit 776 connects the fourth end 710d of the second part 752 of the first end slot 711 to the third end 710c of the first part 751 of the intermediate slot 721. The connecting slit 776 corresponds to the "third intermediate connecting slit." The connecting slit 777 connects the fourth end 710d of the second part 752 of the intermediate slot 721 to the third end 710c of the first part 751 of the intermediate slot 731. The connecting slit 777 corresponds to the "sixth intermediate connecting slit." The connecting slit 778 connects the fourth end 710d of the second part 752 of the intermediate slot 731 to the third end 710c of the first part 751 of the second end slot 741. The connecting slit 778 corresponds to the "second intermediate connecting slit." The connecting slits 776, 777, and 778 are formed in an arc shape.

[0209] (First Electrode, Second Electrode) The conductive layer 601 includes first electrodes 141 defined by slots 711 to 713, 721 to 723, 731 to 733, and 741 to 743. In one example, the first electrodes 141 are formed in a circular shape in a plan view. The first electrodes 141 are disposed spaced apart from each other in the X-axis direction and the Y-axis direction.

[0210] The second parts 752 of the slots 711 to 713, the first parts 751 of the slots 721 to 723, the connecting slits 761b between the slots 711 to 713, the connecting slits 761a, 772, and 776 between the slots 721 to 723 define a first electrode portion 702b. The second parts 752 of the slots 721 to 723, the first parts 751 of the slots 731 to 733, the connecting slits 761b between the slots 721 to 723, the connecting slits 761a, 773, and 777 between the slots 731 to 733 define a second electrode portion 702c. The second part 752 of the slots 731 to 733, the first part 751 of the slots 741 to 743, the connecting slit 761b between the slots 731 to 733, the connecting slit 761a between the slots 741 to 743, the connecting slit 774, and the connecting slit 778 define the third electrode portion 702d.

[0211] The second electrode 150 includes a frame-shaped portion 702a surrounding the slots 711-713, 721-723, 731-733, and 741-743. The first electrode portion 702b is electrically connected to the frame-shaped portion 702a by first connection wirings 703a and 703b. The second electrode portion 702c is electrically connected to the frame-shaped portion 702a by second connection wirings 704a and 704b. The third electrode portion 702d is electrically connected to the frame-shaped portion 702a by third connection wirings 705a and 705b. The first electrode portion 702b, the second electrode portion 702c, the third electrode portion 702d, and the frame-shaped portion 702a constitute the second electrode 150.

[0212] The first connection wirings 703a and 703b may, for example, include lower wiring, vias, etc. The lower wiring of the first connection wiring 703a is formed to intersect with the connecting portion 771a of the connecting slit 771, the connecting slit 772, and the connecting line 782. The lower wiring of the first connection wiring 703a is formed to intersect with the connecting portion 775a of the connecting slit 775, the connecting slit 776, and the connecting line 785. The second connection wirings 704a and 704b may, for example, include lower wiring, vias, etc. The lower wiring of the second connection wiring 704a is formed to intersect with the connecting portion 771b of the connecting slit 771, the connecting slit 773, and the connecting line 783. The lower wiring of the second connection wiring 704b is formed to intersect with the connecting portion 775b of the connecting slit 775, the connecting slit 777, and the connecting line 786. The third connection wirings 705a and 705b may, for example, include lower wirings, vias, etc. The lower wirings of the third connection wirings 705a are formed so as to intersect with the connecting portion 771c of the connecting slit 771, the connecting slit 774, and the connecting line 784. The lower wirings of the third connection wirings 705b are formed so as to intersect with the connecting portion 775c of the connecting slit 775, the connecting slit 778, and the connecting line 787. The first connection wirings 703a and 703b may be formed so as to straddle the connecting slits 771 (771a), 773, 775 (775a), 776, and the connecting lines 782 and 785. The second connection wirings 704a and 704b may be formed so as to straddle the connecting slits 771 (771b), 773, 774 (774b), 777, and the connecting lines 783 and 786. The third connection wirings 705 a and 705 b may be formed so as to straddle the coupling slits 771 ( 771 c ), 773 , 774 ( 774 c ), 778 and the connection lines 784 and 787 .

[0213] (Connection Line) The conductive layer 701 includes a connection line 781 that connects the first electrodes 141 of the slots 711 to 713, 721 to 723, 731 to 733, and 741 to 743 that are arranged in the X-axis direction. The conductive layer 701 includes connection lines 782, 783, and 784 that connect the first electrodes 141 of the slots 713, 723, 733, and 743 that are arranged in the Y-axis direction. The conductive layer 701 also includes connection lines 785, 786, and 787 that connect the first electrodes 141 of the slots 711, 721, 731, and 741.

[0214] (Active Elements) The terahertz device 700 includes a first active element 791 and a second active element 792 disposed in the slots 711 to 713, 721 to 723, 731 to 733, and 741 to 743.

[0215] The first active element 791 is disposed at the first end 710a of the first part 751 of each of the slots 711-713, 721-723, and 731-733. The second active element 792 is disposed at the fourth end 710d of the second part 752. The first end 710a of the first part 751 and the fourth end 710d of the second part 752 are located on opposite sides of the centers of the slots 711-713, 721-723, and 731-733. Therefore, it can be said that the first active element 791 and the second active element 792 are disposed within the slots 711-713, 721-723, and 731-733 on a reference line passing through the centers of the slots 711-713, 721-723, and 731-733.

[0216] For example, the first active element 791 and the second active element 792 may be RTDs. The first active element 791 and the second active element 792 may be diodes or transistors other than RTDs. Examples of other active elements include TUNNETT diodes, IMPATT diodes, GaAs-based FETs, GaN-based FETs, HEMTs, HBTs, and CMOSFETs.

[0217] The first active element 791 and the second active element 792 are connected in parallel to the first electrode 141 and the second electrode 150. (Effects) As described above, the seventh embodiment provides the following effects.

[0218] (7-1) The terahertz device 700 of the seventh embodiment can achieve the same effects as the terahertz device 600 of the sixth embodiment. The terahertz device 700 of the seventh embodiment includes a first electrode 141 partitioned by array-arranged slots 711 to 713, 721 to 723, 731 to 733, and 741 to 743, and a first active element 791 and a second active element 792 arranged in the slots 711 to 713, 721 to 723, 731 to 733, and 741 to 743. This allows the terahertz device 700 to achieve higher output.

[0219] Eighth Embodiment A terahertz device 800 according to an eighth embodiment will be described with reference to FIGS.

[0220] In the eighth embodiment, parts common to the first embodiment are denoted by the same reference numerals as in the first embodiment, and descriptions thereof will be omitted. The terahertz device 800 of the eighth embodiment differs from the terahertz device 100 of the first embodiment mainly in the arrangement of the resistance elements R1 and R2. Therefore, the eighth embodiment will be mainly described with respect to the differences from the first embodiment.

[0221] (Schematic Configuration of Terahertz Device) Fig. 17 is a schematic plan view of an exemplary terahertz device 800 according to the eighth embodiment. Fig. 18 is a schematic plan view showing some components of the terahertz device 800 of Fig. 17, illustrating the active element 171b and the resistive element R2. Fig. 18 is a schematic plan view showing some components of the terahertz device 800 of Fig. 17, illustrating the active element 171a and the resistive element R1. Fig. 20 is a schematic cross-sectional view showing the active element 171a and the resistive element R1 of Fig. 19.

[0222] 17 , a terahertz device 800 according to the eighth embodiment includes a resistive element R1 arranged to overlap with active elements 171 a and 172 a in a planar view, and a resistive element R2 arranged to overlap with active elements 171 b and 172 b in a planar view. The resistive element R1 is connected in parallel to the active elements 171 a and 172 a. The resistive element R2 is connected in parallel to the active elements 171 b and 172 b.

[0223] 18 , the resistor R2 is disposed so as to overlap the active element 171b in a plan view. The resistor R2 includes a first end R2a and a second end R2b. The second end R2b of the resistor R2 is electrically connected to the active element 171b. The first end R2a of the resistor R2 is disposed so as to overlap the first electrode 141. The first end R2a of the resistor R2 is electrically connected to the first electrode 141 by a via 883b.

[0224] 19 , the resistor R1 is disposed so as to overlap the active element 171a in a plan view. The resistor R1 includes a first end R1a and a second end R1b. The second end R1b of the resistor R1 is electrically connected to the active element 171a. The first end R1a of the resistor R1 is disposed so as to overlap the first electrode 141. The first end R1a of the resistor R1 is electrically connected to the first electrode 141 by a via 883a.

[0225] 20, the resistor element R1 is formed on the substrate surface 21 of the semiconductor substrate 20. The resistor element R1 is disposed adjacent to the semiconductor layer 71a of the active element 171a. The GaInAs layer 72a of the active element 171a is disposed so as to overlap both the semiconductor layer 71a and the resistor element R1.

[0226] The semiconductor layer 71a and the resistor R1 may be made of the same material. In one example, the semiconductor layer 71a and the resistor R1 are made of GaInAs. The semiconductor layer 71a and the resistor R1 may be heavily doped with n-type impurities. The resistor R1 may be formed integrally with the semiconductor layer 71a. In FIG. 20, the boundary between the semiconductor layer 71a and the resistor R1 is indicated by a dashed line, but this dashed line does not necessarily mean that there is an actually observable boundary. Although not shown, the resistor R2 is made in the same manner as the resistor R1.

[0227] The terahertz device 800 of the eighth embodiment functions as a detector for detecting terahertz waves. As shown in FIGS. 17 to 19 , the resistive element R2 is electrically connected in parallel with the active elements 171b and 172b. The resistive element R1 is electrically connected in parallel with the active elements 171a and 172a. The resistive elements R2 and R1 of the eighth embodiment can suppress oscillation of the active elements 171b and 172b and the active elements 171a and 172a.

[0228] As described above, the eighth embodiment provides the following advantages in addition to the advantages of the first embodiment. (8-1) Like the terahertz device 100 of the first embodiment, the terahertz device 800 of the eighth embodiment includes active elements 171a and 172a and active elements 171b and 172b arranged on either side of the first electrodes 141 and 142. The terahertz device 800 of the eighth embodiment detects terahertz waves using the active elements 171b and 172b and the active elements 171a and 172a. Therefore, the terahertz device 800 of the eighth embodiment can improve resolution.

[0229] (8-2) The terahertz device 800 of the eighth embodiment includes a resistive element R2 arranged to overlap the active elements 171b and 172b, and a resistive element R1 arranged to overlap the active elements 171a and 172a. The resistive elements R2 and R1 suppress oscillation of the active elements 171b and 172b and the active elements 171a and 172a. Therefore, the terahertz device 800 of the eighth embodiment can suppress oscillation of the active elements 171b and 172b and the active elements 171a and 172a.

[0230] (Modifications) The above embodiment can be modified, for example, as follows. The above embodiment and each of the following modifications can be combined with each other as long as no technical contradiction occurs. In the following modifications, parts that are common to the above embodiment will be assigned the same reference numerals as in the above embodiment, and their description will be omitted.

[0231] The reflective layer 40 may be omitted. The semiconductor substrate 20 may be composed of multiple stacked substrates. The term "on" as used in this disclosure includes both the meanings of "on" and "above," unless the context clearly indicates otherwise. Thus, the expression "a first layer is formed on a second layer" is intended to mean that in some embodiments, the first layer may be in contact with the second layer and disposed directly on the second layer, while in other embodiments, the first layer may be disposed above the second layer without contacting the second layer. In other words, the term "on" does not exclude a structure in which another layer is formed between the first layer and the second layer.

[0232] The Z-axis direction used in this disclosure does not necessarily have to be the vertical direction, nor does it have to completely coincide with the vertical direction. Therefore, various structures according to this disclosure (for example, the structure shown in FIG. 1 ) are not limited to the "up" and "down" in the Z-axis direction described herein being "up" and "down" in the vertical direction. For example, the X-axis direction may be the vertical direction, or the Y-axis direction may be the vertical direction.

[0233] (Supplementary Notes) The technical ideas that can be understood from the present disclosure are described below. Note that, for the purpose of aiding understanding and not intending to be limiting, the components described in the Supplementary Notes are given the reference symbols of the corresponding components in the embodiments. The reference symbols are shown as examples to aid understanding, and the components described in each Supplementary Note should not be limited to the components indicated by the reference symbols.

[0234] (Supplementary Note 1) A substrate (10) including a front surface (11) and a back surface (12), a conductive layer (110) formed on the front surface (11), a plurality of slots (121, 122) formed in the conductive layer (110), a plurality of connecting slits (131a, 131b) formed in the conductive layer (110), and a plurality of active elements (171a, 171b, 172a, 172b) provided in the plurality of slots for oscillating or detecting electromagnetic waves, each of the plurality of slots being formed in an annular shape, the conductive layer (110) including a plurality of first electrodes (141, 142) respectively partitioned by the plurality of slots, connection lines (161) arranged in the plurality of connecting slits and electrically connecting the first electrodes on the inside of two adjacent slots of the plurality of slots, and a second electrode (150) located outside the plurality of slots, A terahertz device, wherein each of the plurality of connecting slits (131a, 131b) connects the two slots and is formed so as to insulate the connection line from the second electrode, the plurality of active elements include two active elements provided for each of the plurality of first electrodes, and the two active elements are arranged at positions sandwiching the first electrode with respect to the center of each of the plurality of slots in a planar view seen from a direction perpendicular to the surface (11).

[0235] (Supplementary Note 2) The plurality of slots include: a first slot (121) formed in an open annular shape and having a first end (121a) and a second end (121b); and a second slot (122) formed in an open annular shape and having a first end (122a) and a second end (122b); the plurality of connecting slits include: a first connecting slit (131a) connecting the first end (121a) of the first slot (121) to the first end (122a) of the second slot (122); and a second connecting slit (131b) connecting the second end (121b) of the first slot (121) to the second end (122b) of the second slot (122); and the plurality of active elements include: A terahertz device as described in Appendix 1, comprising: a first active element (171a) arranged at the first end (121a) in the first slot (121); a second active element (171b) arranged in the first slot (121) on a position opposite the first end with respect to a center (O1) of the first slot; a third active element (172b) arranged in the second slot (122) on a second end (122b); and a fourth active element (172a) arranged in the second slot (122) on a position opposite the second end with respect to a center (O2) of the second slot.

[0236] (Supplementary Note 3) The first slot (121) and the second slot (122) are arranged spaced apart in a first direction (X), the first slot (121) is formed in an open annular shape with the first end and the second end spaced apart in a second direction (Y) perpendicular to the first direction, the second slot (122) is formed in an open annular shape with the first end and the second end spaced apart in the second direction, the first slot and the second slot are arranged such that the first ends (121a, 122a) of the first slot and the second slot are positioned in the same direction in the second direction with respect to the second ends (121b, 122b) of the first slot and the second slot, and the first connecting slit (131a) extends in the first direction to connect the first ends (121a, 122a) to each other, The terahertz device described in Appendix 2, wherein the second connecting slit (131b) extends in the first direction and connects the second ends (121b, 122b) to each other, the first connecting slit and the second connecting slit are arranged parallel to and spaced apart in the second direction, and the connection line (161) extends in the first direction.

[0237] (Supplementary Note 4) The first slot (121) and the second slot (123) are arranged spaced apart in a first direction, the first slot (121) is formed in an open annular shape with the first end (121a) and the second end (121b) spaced apart in a second direction (Y) perpendicular to the first direction, the second slot (123) includes a first part (221) and a second part (222) formed in a semicircular shape and spaced apart from each other in the second direction, and the first part and the second part form an annular shape that is open on both sides in the first direction, and the first part (221) includes: the first end (123a) spaced apart from the first end (121a) of the first slot (121) in the first direction; and a third end (123c) provided on the opposite side of the first end (123a) of the second slot (123), The terahertz device described in Appendix 2, wherein the second part (222) includes: a second end (123b) arranged spaced apart in the first direction from the second end (121b) of the first slot; and a fourth end (123d) provided on the opposite side of the second end (123b) of the second slot (123) and spaced apart in the second direction from the third end; and the fourth active element (173a) is arranged at the third end (123c).

[0238] (Supplementary Note 5) The terahertz device according to Supplementary Note 2, wherein the first slot (321) and the second slot (322) are arranged at a distance from each other in a second direction (Y), the first slot is formed in an annular shape with the first and second ends (321a, 321b) of the first slot arranged at a distance from each other in the second direction, the second slot is formed in an annular shape with the first and second ends (322a, 322b) of the second slot arranged at a distance from each other in the second direction, the first end (321a) of the first slot (321) is arranged on the opposite side to the second slot (322) with respect to the second end (321b) of the first slot, and the first end (322a) of the second slot (322) is arranged on the opposite side to the first slot (321) with respect to the second end (322b) of the second slot.

[0239] (Supplementary Note 6) The first slot (321) includes a first part (331a) and a second part (331b) formed in a semicircular shape and spaced apart from each other in the second direction, and is formed into an annular shape that is open on both sides by the first part and the second part; the second slot (322) includes a third part (332a) and a fourth part (332b) formed in a semicircular shape and spaced apart from each other in the second direction, and is formed into an annular shape that is open on both sides by the third part and the fourth part; the first part has the first end (321a) of the first slot and a third end (321c) arranged opposite to the first end; and the second part has the second end (321b) of the first slot and a fourth end (321d) arranged opposite to the second end. The third part has the first end (322a) of the second slot and a third end (322c) located on the opposite side to the first end, the fourth part has the second end (322b) of the second slot and a fourth end (322d) located on the opposite side to the second end, the first connecting slit (341a) connects the first end (321a) of the first part (331a) to the first end (322a) of the third part (332a), the second connecting slit (341b) connects the second end (321b) of the second part (331a) to the second end (322b) of the fourth part (332b), and the multiple connecting slits are The terahertz device according to Supplementary Note 5, further comprising: a third connecting slit (342a) that connects the third end (321c) of the first part (331a) and the third end (322c) of the third part (332a); and a fourth connecting slit (342b) that connects the fourth end (321d) of the second part (331b) and the fourth end (322d) of the fourth part (332b).

[0240] (Supplementary Note 7) The plurality of slots are arranged in a second direction and include first end slots (613, 713) and second end slots (633, 743) disposed at both ends in the second direction, and at least one intermediate slot (623, 723, 733) disposed between the first end slots and the second end slots, the first end slots (613, 713) being formed in an open annular shape and including first ends (610a, 710a) and second ends (610b, 710b) spaced apart in the second direction, and the second end slots (633, 743) being formed in an annular shape that is open in the same direction as the first end slots and including first ends (610a, 710a) and second ends (610b, 710b) spaced apart in the second direction. The intermediate slots (623, 723, 733) are formed in an annular shape that opens in the same direction as the first end slots and include first ends (610a, 710a) and second ends (610b, 710b) that are spaced apart in the second direction, the first ends of the first end slots being located on the opposite side of the intermediate slots with respect to the second ends of the first end slots, the second ends of the second end slots being located on the opposite side of the intermediate slots with respect to the first ends of the second end slots, and the first ends of the intermediate slots being located on the first end slot side with respect to the second ends of the intermediate slots, and the multiple connecting slits include: first connecting slits (671, 771) that connect the first ends (610a, 710a) of the first end slots (613, 713) and the second ends (610b, 710b) of the second end slots (633, 743); a first intermediate connecting slit (672, 772) connecting the second end (610b, 710b) of the first end slot (613, 713) and the first end (610a, 710a) of the intermediate slot (623, 723); and a second intermediate connecting slit (673, 773) connecting the second end (610b, 710b) of the intermediate slot (623, 733) and the first end (610a, 710a) of the second end slot.774), and the plurality of active elements include: a first active element (791) disposed at the first end (610a, 710a) of each of the first end slot, the second end slot, and the intermediate slot; and a second active element (792) disposed at a position opposite the first end with respect to the center of each of the first end slot, the second end slot, and the intermediate slot.

[0241] (Supplementary Note 8) The terahertz device described in Supplementary Note 7, wherein the at least one intermediate slot (623, 723, 733) is a plurality of intermediate slots, the plurality of intermediate slots are arranged in the second direction, and the plurality of connecting slits include a fifth intermediate connecting slit (773) that connects the second end (710b) of one (723) of two adjacent intermediate slots (723, 733) among the plurality of intermediate slots in the second direction to the first end (710a) of the other (733) of the two adjacent intermediate slots.

[0242] (Supplementary Note 9) The first end slot (611, 711) includes a first part (651, 751) and a second part (652, 752) formed in a semicircular shape and spaced apart from each other in the second direction, and is formed into an annular shape that is open on both sides in the first direction by the first part and the second part; the second end slot (631, 741) includes a third part and a fourth part formed in a semicircular shape and spaced apart from each other in the second direction, and is formed into an annular shape that is open on both sides in the first direction by the third part and the fourth part; and the intermediate slot (621, 721, 731) includes a fifth part and a sixth part formed in a semicircular shape and spaced apart from each other in the second direction, and is formed into an annular shape that is open on both sides in the first direction by the fifth part and the sixth part. The first part includes the first end (610a, 710a) of the first end slot and a third end (610c, 710c) opposite the first end, the second part includes the second end (610b, 710b) of the first end slot and a fourth end (610d, 710d) opposite the second end, the third part includes the first end of the second end slot and a third end opposite the first end, the fourth part includes the second end of the second end slot and a fourth end opposite the second end, the fifth part includes the first end of the intermediate slot and a third end opposite the first end, the sixth part includes the second end of the intermediate slot and a fourth end opposite the second end, and the multiple connecting slits are a second connecting slit (674, 775) connecting the third end (610c, 710c) of the first part of the first end slot (611, 711) and the fourth end (610d, 710d) of the second part of the second end slot (631, 741); a third intermediate connecting slit (675, 776) connecting the fourth end (710d) of the second part of the first end slot (611, 711) and the third end (610c, 710c) of the fifth part of the intermediate slot (621, 721);The terahertz device according to claim 7 or 8, further comprising a fourth intermediate connecting slit (676, 778) connecting the first end (610c, 710d) of the first part of the second end slot (631, 741) with the third end (610c, 710c) of the first part of the second end slot (631, 741).

[0243] (Supplementary Note 10) The terahertz device described in Supplementary Note 9, wherein the at least one intermediate slot (623, 723, 733) is a plurality of intermediate slots, and the plurality of connecting slits include a sixth intermediate connecting slit (777) that connects the fourth end (710d) of the sixth part and the third end (710c) of the fifth part in two intermediate slots (721, 731) adjacent to each other in the second direction among the plurality of intermediate slots.

[0244] (Supplementary Note 11) The terahertz device according to any one of Supplementary Note 1 to Supplementary Note 10, wherein the two active elements (171a, 171b, 172a, 172b) are arranged on a reference line (LM1, LM2) passing through the centers (O1, O2) of the plurality of slots (121, 122) and at positions sandwiching the first electrode (141, 142) when viewed from a direction perpendicular to the surface, and the reference line (LM1, LM2) is inclined with respect to the connection line (161) when viewed from a direction perpendicular to the surface.

[0245] (Supplementary Note 12) The terahertz device according to any one of Supplementary Note 1 to Supplementary Note 11, wherein the length of the connection line (161) is 1 / 2 of the effective wavelength λg.

[0246] (Supplementary Note 13) The terahertz device according to any one of Supplementary Notes 1 to 12, wherein the length of the connection line (161) is equal to an effective wavelength λg.

[0247] (Supplementary Note 14) The terahertz device according to any one of Supplementary Note 1 to Supplementary Note 13, further comprising a plurality of resistive elements (R1, R2) electrically connected in parallel with the plurality of active elements (171a, 171b, 172a, 172b).

[0248] (Supplementary Note 15) The terahertz device according to Supplementary Note 14, wherein the plurality of resistive elements (R1, R2) are connected to a virtual short-circuit point of the plurality of first electrodes (141, 142).

[0249] (Supplementary Note 16) The terahertz device according to Supplementary Note 14, wherein the plurality of resistive elements (R1, R2) are arranged to overlap the plurality of active elements (171a, 171b, 172a, 172b) in the plan view.

[0250] (Supplementary Note 17) The terahertz device according to any one of Supplementary Notes 1 to 16, further comprising a plurality of first electrode pads (181, 182) connected to the plurality of first electrodes (141, 142), respectively.

[0251] (Supplementary Note 18) The terahertz device according to Supplementary Note 7 or Supplementary Note 8, further comprising one first electrode pad (181) connected to the plurality of first electrodes (141, 142) arranged in the second direction.

[0252] (Supplementary Note 19) The terahertz device according to Supplementary Note 17, further comprising a plurality of second electrode pads (181b, 182b) formed on the second electrode for the plurality of first electrodes, respectively.

[0253] (Supplementary Note 20) The terahertz device according to any one of Supplementary Notes 1 to 18, further comprising one second electrode pad (181b) formed on the second electrode.

[0254] (Supplementary Note 21) The terahertz device according to any one of Supplementary Note 1 to Supplementary Note 18, further comprising a reflective layer (40) provided on the rear surface of the substrate (10) and reflecting the electromagnetic waves, the reflective layer being arranged to overlap with the plurality of slots in the planar view.

[0255] (Supplementary Note 22) The terahertz device according to any one of Supplementary Note 1 to Supplementary Note 21, wherein the plurality of active elements are any of resonant tunneling diodes, Tannett diodes, IMPATT diodes, GaAs-based field effect transistors, GaN-based FETs, high electron mobility transistors, heterojunction bipolar transistors, and CMOSFETs.

[0256] The above description is merely illustrative. Those skilled in the art will recognize that many more possible combinations and permutations are possible other than the components and methods (manufacturing processes) listed for the purpose of illustrating the technology of the present disclosure. The present disclosure is intended to embrace all alternatives, modifications, and variations that fall within the scope of the present disclosure, including the claims.

[0257] 100, 200, 300, 400, 500, 600, 700, 800 Terahertz device 10 Substrate 11 Front surface 12 Back surface 13-16 Side surface 20 Semiconductor substrate 21 Substrate front surface 22 Substrate back surface 30 Insulating layer 31 Insulating front surface 32 Insulating back surface 40 Reflecting layer 51-53 Connection wiring 110 Conductive layer 121 Slot 121a First end 121b Second end 121R Slot antenna 122 Slot 122a First end 122b Second end 122R Slot antenna 123 Slot 123a-123d First to fourth end portions 131a, 131b Connecting slits 132a, 132b Connecting slits 141-143 First electrode 150 Second electrode 161, 162 Connection lines 171a, 171b Active elements 172a, 172b Active elements 173a, 173b Active elements 181, 182, 183 First electrode pads 181b, 182b, 183b Second electrode pads 210 Conductive layer 221, 222 First and second parts 301 Conductive layer 321 Slots 321a to 321d First to fourth ends 322 Slots 322a to 322d First to fourth ends 331a, 331b First and second parts 332a, 332b Third and fourth parts 341a First connecting slit 341a, 341b Connecting slit 342a, 342b Connecting slit 361, 362 Connection lines 371a, 371b Active elements 372a, 372b Active elements 401 Conductive layer 441a, 441b Connecting slits 442a, 442b Connecting slits 461, 462 Connecting lines 501 Conductive layer 601 Conductive layer 611 to 613 Slots 621 to 623 Slots 631 to 633 Slots 651 First part 652 Second part 661a, 661b Connecting slits 671 to 676 Connecting slits 671a, 671b Connecting portions 674a, 674b Connecting portions 681 to 685 Connecting lines 691, 692 First,Second active element 701 Conductive layer 711 to 713 Slots 721 to 723 Slots 731 to 733 Slots 741 to 743 Slots 751 First part 752 Second part 761a, 761b Connecting slits 771 to 778 Connecting slits 781 to 787 Connecting lines 791, 792 First and second active elements λg Effective wavelength O1 to O3 Center R1, R2 Resistive elements

Claims

1. A substrate including the front and back surfaces, A conductive layer formed on the surface, Multiple slots formed in the conductive layer, Multiple connecting slits formed in the conductive layer, Multiple active elements for oscillating or detecting electromagnetic waves are provided within the aforementioned multiple slots, Includes, Each of the aforementioned plurality of slots is formed in an annular shape, The conductive layer is A plurality of first electrodes, each partitioned by the plurality of slots, A connecting line is arranged within the plurality of connecting slits and electrically connects the first electrodes inside two adjacent slots among the plurality of slots, A second electrode located outside the aforementioned plurality of slots, Includes, Each of the plurality of connecting slits connects the two slots and is formed to insulate the connecting line from the second electrode. The plurality of active elements include two active elements provided for each of the plurality of first electrodes, The two active elements are positioned in a plan view taken from a direction perpendicular to the surface, with respect to the center of each of the plurality of slots, with respect to the first electrode. Terahertz device.

2. The aforementioned multiple slots are, A first slot formed in an open ring shape, having a first end and a second end, A second slot formed in an open ring shape, having a first end and a second end, Includes, The aforementioned multiple connecting slits are A first connecting slit that connects the first end of the first slot and the first end of the second slot, A second connecting slit that connects the second end of the first slot and the second end of the second slot, Includes, The aforementioned plurality of active elements are, A first active element positioned at the first end within the first slot, A second active element is positioned within the first slot at a location opposite to the first end relative to the center of the first slot, A third active element positioned at the second end within the second slot, A fourth active element is positioned within the second slot, on the opposite side of the second end from the center of the second slot, including, The terahertz device according to claim 1.

3. The first slot and the second slot are arranged to be spaced apart in the first direction. The first slot is formed in an open annular shape, with the first end and the second end spaced apart in a second direction perpendicular to the first direction. The second slot is formed in an open annular shape with the first end and the second end spaced apart in the second direction. The first slot and the second slot are arranged such that the first ends of the first slot and the second slot are located in the same direction in the second direction relative to the second ends of the first slot and the second slot. The first connecting slit extends in the first direction and connects the first ends together. The second connecting slit extends in the first direction and connects the second ends together. The first connecting slit and the second connecting slit are arranged parallel to each other and spaced apart in the second direction, and the connecting line extends in the first direction. The terahertz device according to claim 2.

4. The first slot and the second slot are arranged to be spaced apart in the first direction. The first slot is formed in an open annular shape, with the first end and the second end spaced apart in a second direction perpendicular to the first direction. The second slot includes a first part and a second part that are formed in a semicircular shape and are spaced apart from each other in the second direction, and the first part and the second part form an annular structure that opens to both sides in the first direction. The first part is, The first end of the first slot and the first end positioned at a distance from each other in the first direction, A third end provided on the side of the second slot opposite to the first end, Includes, The aforementioned second part is, The second end of the first slot and the second end positioned at a distance from each other in the first direction, A fourth end is provided on the side of the second slot opposite to the second end, and is spaced apart from the third end in the second direction, Includes, The fourth active element is located at the third end, The terahertz device according to claim 2.

5. The first slot and the second slot are arranged to be spaced apart in the second direction. The first slot is formed in an annular shape with its first and second ends spaced apart in the second direction. The second slot is formed in an annular shape with the first and second ends of the second slot spaced apart in the second direction. The first end of the first slot is positioned on the opposite side of the second slot from the second end of the first slot, The first end of the second slot is positioned on the opposite side of the first slot from the second end of the second slot. The terahertz device according to claim 2.

6. The first slot includes a first part and a second part that are formed in a semicircular shape and are spaced apart from each other in the second direction, and is formed in an annular shape that opens to both sides by the first part and the second part. The second slot includes a third part and a fourth part that are formed in a semicircular shape and are spaced apart from each other in the second direction, and is formed in an annular shape that opens to both sides by the third part and the fourth part. The first part has a first end of the first slot and a third end located on the opposite side of the first end. The second part has the second end of the first slot and the fourth end located on the opposite side of the second end. The third part has a first end of the second slot and a third end located on the opposite side of the first end. The fourth part has the second end of the second slot and the fourth end located on the opposite side of the second end. The first connecting slit connects the first end of the first part and the first end of the third part. The second connecting slit connects the second end of the second part to the second end of the fourth part. The aforementioned multiple connecting slits are A third connecting slit that connects the third end of the first part and the third end of the third part, A fourth connecting slit that connects the fourth end of the second part and the fourth end of the fourth part, including, The terahertz device according to claim 5.

7. The plurality of slots are arranged in a second direction and include first end slots and second end slots located at both ends in the second direction, and at least one intermediate slot located between the first end slots and the second end slots. The first end slot is formed in an open annular shape and includes a first end and a second end that are spaced apart in the second direction. The second end slot is formed in an annular shape opening in the same direction as the first end slot and includes a first end and a second end arranged spaced apart in the second direction. The intermediate slot is formed in an annular shape opening in the same direction as the first end slot and includes a first end and a second end arranged spaced apart in the second direction. The first end of the first end slot is positioned on the opposite side of the intermediate slot from the second end of the first end slot, The second end of the second end slot is positioned on the opposite side of the intermediate slot from the first end of the second end slot, The first end of the intermediate slot is positioned on the side of the first end slot relative to the second end of the intermediate slot. The aforementioned multiple connecting slits are A first connecting slit that connects the first end of the first end slot and the second end of the second end slot, A first intermediate connecting slit that connects the second end of the first end slot and the first end of the intermediate slot, A second intermediate connecting slit connects the second end of the intermediate slot and the first end of the second end slot, Includes, The aforementioned plurality of active elements are, A first active element is disposed at the first end of each of the first end slot, the second end slot, and the intermediate slot, A second active element is positioned opposite to the first end with respect to the center of each of the first end slot, the second end slot, and the intermediate slot, including, The terahertz device according to claim 1.

8. The aforementioned at least one intermediate slot is a plurality of intermediate slots, The plurality of intermediate slots are arranged in the second direction, The plurality of connecting slits include a fifth intermediate connecting slit that connects the second end of one of two adjacent intermediate slots in the second direction among the plurality of intermediate slots to the first end of the other of the two adjacent intermediate slots. The terahertz device according to claim 7.

9. The first end slot includes a first part and a second part that are formed in a semicircular shape and are spaced apart from each other in the second direction, and the first part and the second part form an annular shape that opens to both sides in the first direction. The second end slot includes a third and a fourth part that are formed in a semicircular shape and are spaced apart from each other in the second direction, and the third and fourth parts form an annular shape that opens to both sides in the first direction. The intermediate slot includes a fifth part and a sixth part that are formed in a semicircular shape and are spaced apart from each other in the second direction, and the fifth part and the sixth part form an annular shape that opens to both sides in the first direction. The first part includes the first end of the first end slot and the third end opposite to the first end, The second part includes the second end of the first end slot and the fourth end opposite to the second end, The third part includes the first end of the second end slot and the third end opposite to the first end, The fourth part includes the second end of the second end slot and the fourth end opposite to the second end, The fifth part includes the first end of the intermediate slot and the third end opposite to the first end, The sixth part includes the second end of the intermediate slot and the fourth end opposite to the second end, The aforementioned multiple connecting slits are A second connecting slit connects the third end of the first part of the first end slot and the fourth end of the second part of the second end slot, A third intermediate connecting slit connects the fourth end of the second part of the first end slot and the third end of the fifth part of the intermediate slot, A fourth intermediate connecting slit connects the fourth end of the sixth part of the intermediate slot and the third end of the first part of the second end slot, including, The terahertz device according to claim 7.

10. The aforementioned at least one intermediate slot is a plurality of intermediate slots, The plurality of connecting slits include a sixth intermediate connecting slit that connects the fourth end of the sixth part and the third end of the fifth part to each other in two adjacent intermediate slots in the second direction among the plurality of intermediate slots. The terahertz device according to claim 9.

11. The two active elements are positioned on a reference line passing through the center of each of the plurality of slots, with the first electrode in between, when viewed from a direction perpendicular to the surface. The aforementioned reference line is inclined with respect to the connecting line when viewed from a direction perpendicular to the surface. The terahertz device according to claim 1.

12. The length of the connecting line is half the effective wavelength λg. The terahertz device according to claim 1.

13. The length of the connecting line is equal to the effective wavelength λg. The terahertz device according to claim 1.

14. The plurality of active elements include a plurality of resistive elements electrically connected in parallel, The terahertz device according to claim 1.

15. The plurality of resistive elements are connected to the virtual short-circuit point of the plurality of first electrodes. The terahertz device according to claim 14.

16. In the plan view, the plurality of resistive elements are arranged to overlap with the plurality of active elements. The terahertz device according to claim 14.

17. The aforementioned multiple active elements are any of the following: resonant tunnel diodes, tannet diodes, INPAT diodes, GaAs-based field-effect transistors, GaN-based FETs, high electron-mobility transistors, heterojunction bipolar transistors, or CMOSFETs. A terahertz device according to any one of claims 1 to 16.