JP2011155433A - Oscillation element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an oscillation element for improving directivity in the lateral direction and oscillating in the lateral direction to a substrate with high efficiency and high output by using the insulator substrate of a low dielectric constant. <P>SOLUTION: The oscillation element includes: a first electrode 4 (4a) arranged on the insulator substrate 10; an insulating layer 3 arranged on the first electrode 4a; an interlayer insulating film 9 arranged on the insulator substrate; a second electrode 2 arranged on the interlayer insulating film and arranged facing the first electrode 4 through the insulating layer 3 to the first electrode 4a; a semiconductor layer 91a arranged on the second electrode 2; an MIM reflector 50 formed between the first electrode 4a and the second electrode 2 holding the insulating layer 3 therebetween; a resonator 60 arranged on the insulator substrate 10 adjacently to the MIM reflector 50; an active element 90 arranged at the almost center part of the resonator 60; a waveguide 70 arranged on the insulator substrate adjacently to the resonator 60; and a horn opening 80 arranged on the insulator substrate 10 adjacently to the waveguide 70. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an oscillating element, and in particular, by using an insulating substrate having a low dielectric constant, electromagnetic waves can be taken out in a horizontal direction with high directivity and efficiently, and terahertz oscillation is easy to integrate. It relates to an element.

  In recent years, electronic devices such as transistors have been miniaturized, and the size has become nano-sized. Therefore, a new phenomenon called a quantum effect has been observed. And development aiming at realization of ultra-high-speed devices and new functional devices using this quantum effect is in progress.

On the other hand, in such an environment, an attempt to perform large-capacity communication, information processing, imaging, measurement, or the like using a frequency range of 1 THz (10 ¹² Hz) to 10 THz, particularly referred to as a terahertz band. Has been done. This frequency region is an undeveloped region between light and radio waves. If a device that operates in this frequency band is realized, in addition to the above-mentioned imaging, large-capacity communication / information processing, physical properties, astronomy, living things, etc. It is expected to be used for many purposes such as measurement in various fields.

  As an element that oscillates a high frequency electromagnetic wave having a frequency in the terahertz band, an element having a structure in which a fine slot antenna is integrated in an active device such as a transistor or a diode is known (for example, see Non-Patent Document 1).

  In addition, an element having a structure in which a metal and an insulating layer are added on the slot lines at both ends of the antenna and short-circuited at a high frequency is disclosed (for example, see Non-Patent Documents 1 and 2). This oscillation element is easy to manufacture and has features such as being suitable for miniaturization.

  FIG. 17 is a schematic bird's-eye view of an oscillation element manufactured by combining an RTD (Resonant Tunneling Diode) and a slot antenna. An active element 109 made of RTD is disposed near the center of the slot antenna 100, and a metal and insulator are laminated on both ends of the slot antenna 100, and the insulator is sandwiched between upper and lower electrode metals, and an MIM (Metal Insulator Metal) structure. Is formed. Here, the MIM structure includes the second electrode 104 / the insulating layer 103 / the first electrode 102, and is short-circuited in a high frequency manner.

  The second electrode 104 has two concave portions 105 and 106 formed in the central portion of the portion overlapping the first electrode 102 with the insulating layer 103 interposed between the two concave portions 105 and 106. In this state, the convex portion 107 is formed. A protrusion 108 is formed at a substantially central portion of the protrusion 107 of the second electrode 104, and an active element 109 is disposed below the protrusion 108 so as to be sandwiched between the first electrode 102. Yes. A DC power source 115 is connected to the second electrode 104 and the first electrode 102, and a parasitic oscillation suppression resistor 114 formed of a material such as bismuth (Bi) is connected to prevent parasitic oscillation. Has been.

  As a constituent material of the semiconductor substrate 101, semi-insulating (SI) InP is used. The slot antenna 100 made on both sides of the RTD serves as both a resonator and an electromagnetic wave radiation antenna. This oscillation element has a structure in which electromagnetic waves are radiated in two directions, upward and downward, with respect to the semiconductor substrate 101. For this reason, for example, as shown in FIG. 18, it is necessary to newly provide a silicon hemisphere lens 120 for condensing electromagnetic waves (hν) radiated in the vertical direction.

  In the conventional terahertz oscillation device shown in FIG. 17, an active element 109 such as a transistor or a diode disposed on the same plane as the insulating layer 103 is disposed at the center of the slot antenna 100, and both ends of the slot line are bent at right angles. This portion is covered with a metal / insulator / metal layer structure. For this reason, the portions covered with the metal / insulator / metal layer structure constitute the RF reflectors 150a and 150b, which are short-circuited in high frequency, and the slot antenna 100 is constructed. Since the slot antenna 100 is in an open state in terms of direct current, direct current can be supplied to the active element 109.

In FIG. 17 and FIG. 18, since the air above the slot antenna 100 is air, the relative permittivity ε _air = 1. Below the slot antenna 100, since an InP substrate is used as the semiconductor substrate 101, the relative dielectric constant ε _InP = 12.01. Here, the ratio of the oscillation output below the slot antenna 100 to the total oscillation output is represented by ε _InP ^3/2 / (ε _air ^3/2 + ε _InP ^3/2 ) = 0.97. That is, about 97% of the total oscillation output is radiated to the InP substrate side.

Oscillation elements having this structure realize oscillation in a terahertz band of 1.02 THz (10 ¹² Hz) at room temperature (see Non-Patent Document 3). That is, according to the prototyped element, the oscillation frequency of the fundamental wave was 342 GHz and the output was 23 μW. And it is reported that 1.02 THz electromagnetic waves were simultaneously output as the third harmonic of the fundamental wave, and the output of this third harmonic was 0.59 μW (see Non-Patent Document 3).

  However, the oscillation elements proposed in these Non-Patent Documents 1, 2, and 3 have insufficient high-frequency short-circuit structures, and therefore leak in the direction of the RF reflectors 150a and 150b perpendicular to the direction in which high-frequency electromagnetic waves oscillate. There was a problem that a high output could not be obtained due to loss of minutes.

  Further, in the terahertz oscillation device having the structure as shown in FIG. 17, the power of electromagnetic waves oscillated in the lateral direction is relatively small, so that it is not practically used for integration on a substrate.

  On the other hand, even in the case of electromagnetic waves in a frequency band with a relatively wide bandwidth that are oscillated from variable frequency oscillation elements, high efficiency and high output electromagnetic waves are oscillated without leakage from the slot line over the entire oscillation frequency. A terahertz oscillation element that can be used is also disclosed (for example, see Patent Document 1). In Patent Document 1, a multi-stage stub is provided at both ends of a fine slot antenna including an active device constituted by an RTD or the like, and a frequency band of an electromagnetic wave having a relatively wide bandwidth is reflected from the multi-stage stub, By providing this multi-stage stub circuit, leakage of electromagnetic waves oscillated from the active element is reflected and returned to the active element, so that a wide-band, high-power oscillation output can be obtained, and the active element used for the oscillation element has a variable frequency. In this case, an oscillation output can be obtained correspondingly.

  However, since the oscillation elements disclosed in Non-Patent Document 3 and Patent Document 1 radiate electromagnetic waves in a direction perpendicular to the substrate, as shown in FIG. 18, electromagnetic waves (hν) radiated in the vertical and vertical directions are emitted. It is necessary to newly provide a silicon hemispherical lens 120 for condensing light, and there is a problem in integrating on a substrate.

  In addition, since the conventional terahertz oscillation device uses a semiconductor substrate made of an InP substrate having a relatively high dielectric constant as a substrate, about 97% of the total oscillation output is radiated to the InP substrate side. The oscillation output in the horizontal direction was relatively small and the directivity was extremely low.

JP 2007-124250 A

N. Orihashi, S. Hattori, and M. Asada: “Millimeter and Submillimeter Oscillators Using Resonant Tunneling Diode and Slot Antenna with Stacked-Layer Slot Antenna”, Jpn.J.Appl.Phys.vol.67, L1309 (2004). N. Orihashi, S. Hattori, and M. Asada: “Millimeter and Submillimeter Oscillator Using Resonant Tunneling Diode and Slot Antenna with a novel RF short structure”, Int. Conf. Infrared and Millimeter Waves (IRMMW2004), International Conference on Waves) Karlsruhe (Germany), M5.3 (Sept. 2004) pp.121-122. N. Orihashi, S. Suzuki, and M. Asada: “Harmonic Generation of 1THz in Sub-THz Oscillating Resonant Tunneling Diode” [IRMMW2005 / THz2005 (The Joint 30th International Conference on Infrared and Millimeter Waves and 13th Infrared Conference on Terahertz Electronics) 2005.9 .19-23]

  The object of the present invention is to improve the directivity in the lateral direction by using an insulating substrate having a low dielectric constant, and can oscillate with high directivity in the lateral direction with high efficiency and high output. An object of the present invention is to provide an easily oscillating element.

  According to one aspect of the present invention for achieving the above object, an insulator substrate, a first electrode disposed on the insulator substrate, an insulating layer disposed on the first electrode, An interlayer insulating film disposed on the insulator substrate, disposed on the interlayer insulating film, and opposed to the first electrode with the insulating layer interposed therebetween with respect to the first electrode. A second electrode; a semiconductor layer disposed on the second electrode; an MIM reflector formed between the first electrode and the second electrode across the insulating layer; and adjacent to the MIM reflector A resonator disposed between the first electrode and the second electrode opposed to each other on the insulator substrate, an active element disposed at a substantially central portion of the resonator, and the resonator. Adjacent, disposed between the first electrode and the second electrode facing the insulator substrate There is provided an oscillating device comprising: a waveguide, and a horn opening disposed between the first electrode and the second electrode facing the insulator substrate, adjacent to the waveguide. .

  According to another aspect of the present invention, an insulator substrate, a first electrode disposed on the insulator substrate, an insulating layer disposed on the first electrode, and the insulator substrate An interlayer insulating film disposed; and a second electrode disposed on the interlayer insulating film and disposed opposite to the first electrode through the insulating layer with respect to the first electrode; A first slot line electrode disposed adjacent to the first electrode on the insulator substrate and opposite to the second electrode, opposite the first electrode; and on the insulator substrate A second slot line electrode disposed adjacent to the second electrode and opposite to the first electrode and opposite to the second electrode; and the first electrode sandwiching the insulating layer therebetween And an MIM reflector formed between the second electrode and the insulating layer adjacent to the MIM reflector. A resonator disposed between the first electrode and the second electrode opposed to each other on a substrate; an active element disposed at a substantially central portion of the resonator; and the insulation adjacent to the resonator. A first waveguide disposed between the first electrode and the second electrode facing the body substrate; and the first waveguide facing the insulator substrate adjacent to the first waveguide. A first horn opening disposed between an electrode and the second electrode; a second waveguide disposed between the first electrode and the first slot line electrode opposed to the insulator substrate; A second horn opening disposed between the first electrode facing the insulator substrate and the first slot line electrode adjacent to the second waveguide, and facing the insulator substrate. A third waveguide disposed between the second electrode and the second slot line electrode; and Adjacent to the waveguide, the oscillation element and a third horn aperture disposed between said second slot line electrode and the second electrode facing the insulator substrate is provided.

  According to the present invention, by using an insulating substrate having a low dielectric constant, the directivity in the lateral direction is improved, and it is possible to oscillate with high directivity in the lateral direction with respect to the substrate with high efficiency and high output. It is possible to provide an easily oscillating element.

1 is a schematic bird's-eye view of a terahertz oscillation device according to a first embodiment of the present invention. The typical top view of the pattern structure of the 1st electrode 4, the 2nd electrode 2a, and the semiconductor layer 91a corresponding to FIG. In the terahertz oscillation device according to the first embodiment of the present invention, (a) a schematic cross-sectional structure diagram taken along line II in FIG. 1, and (b) a schematic cross-sectional structure along line II-II in FIG. Figure. FIG. 3A is a schematic sectional view of a comparative example corresponding to FIG. 3A, and FIG. 3B is a schematic sectional view of a comparative example corresponding to FIG. The typical bird's-eye view which shows a mode that the insulator board | substrate was affixed on the sample surface and the semiconductor substrate was removed in the terahertz oscillation element which concerns on the 1st Embodiment of this invention. The typical bird's-eye view which shows a mode that it saw from the back surface of FIG. FIG. 2 is a schematic bird's-eye view after forming an electrode pattern on a semiconductor substrate in the terahertz oscillation device according to the first embodiment of the present invention. In the terahertz oscillation device according to the first embodiment of the present invention, (a) a schematic cross-sectional structure diagram taken along line II in FIG. 7, and (b) a schematic cross-sectional structure along line II-II in FIG. Figure. FIG. 8A is a schematic sectional view of a comparative example corresponding to FIG. 8A, and FIG. 8B is a schematic sectional view of a comparative example corresponding to FIG. FIG. 2 is a schematic cross-sectional structure diagram of a resonant tunneling diode (RTD) used in the terahertz oscillation device according to the first embodiment of the present invention. The electromagnetic field simulation result of the terahertz oscillation element which concerns on the 1st Embodiment of this invention. The simulation result of the electric field pattern on the XY plane of the terahertz oscillation element which concerns on the 1st Embodiment of this invention. 1A is a schematic circuit configuration diagram of a terahertz oscillation device according to a first embodiment of the present invention, and FIG. 1B is an equivalent circuit configuration diagram of a terahertz oscillation device according to a first embodiment of the present invention. (A) Schematic plan view of the electrode pattern structure of the terahertz oscillation device according to the first modification of the first embodiment of the present invention, (b) Terahertz according to the second modification of the first embodiment of the present invention. The typical top view of the electrode pattern structure of an oscillation element. FIG. 6 is a schematic plan view of a terahertz oscillation device according to a second embodiment of the present invention. FIG. 6 is a schematic plan view of a terahertz oscillation device according to a third embodiment of the present invention. The typical bird's-eye view which shows the structure of the conventional terahertz oscillation element. The typical bird's-eye view which shows the structure of the conventional terahertz oscillation element arrange | positioned on a silicon hemisphere lens.

  Next, embodiments of the present invention will be described with reference to the drawings. In the following, the same reference numerals are assigned to the same blocks or elements to avoid duplication of explanation and simplify the explanation. It should be noted that the drawings are schematic and different from the actual ones. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

  The following embodiments exemplify apparatuses and methods for embodying the technical idea of the present invention. In the embodiments of the present invention, the arrangement of each component is as follows. Not specific. Various modifications can be made to the embodiment of the present invention within the scope of the claims.

[First embodiment]
A schematic bird's-eye view structure of the terahertz oscillation device according to the first embodiment of the present invention is expressed as shown in FIG. 1, and the first electrode 4, the second electrode 2a, and the semiconductor corresponding to FIG. A schematic plan view of the pattern structure of the layer 91a is expressed as shown in FIG. Moreover, the schematic cross-sectional structure along the II line of FIG. 1 is represented as shown in FIG. 3A, and the schematic cross-sectional structure along the II-II line of FIG. 1 is shown in FIG. Represented as shown.

  The terahertz oscillation device according to the first embodiment includes an insulator substrate 10 and a first electrode 4 (4a, 4b, 4c) disposed on the insulator substrate 10, as shown in FIGS. An insulating layer 3 disposed on the first electrode 4a, an interlayer insulating film 9 disposed on the insulator substrate 10, and an interlayer insulating film 9 disposed on the interlayer insulating film 9 and with respect to the first electrode 4a The second electrodes 2 and 2a disposed opposite to the first electrode 4 with the insulating layer 3 interposed therebetween, the semiconductor layer 91a disposed on the second electrode 2, and the first layer sandwiching the insulating layer 3 The MIM reflector 50 formed between the electrode 4 a and the second electrode 2, and adjacent to the MIM reflector 50 and disposed between the first electrode 4 and the second electrode 2 facing on the insulator substrate 10. Resonator 60, active element 90 disposed substantially at the center of resonator 60, and adjacent to resonator 60, insulation A waveguide 70 disposed between the first electrode 4 and the second electrode 2 facing each other on the substrate 10, and the first electrode 4 and the second electrode facing each other on the insulator substrate 10 adjacent to the waveguide 70. A horn opening 80 disposed between the two electrodes 2.

  The active element 90 is typically an RTD, but can be composed of other diodes or transistors. Other active elements include, for example, a tannet (TUNNETT) diode, an impulse (Impact Ionization Avalanche Transit Time) diode, a GaAs field effect transistor (FET), a GaN FET, a high An electron mobility transistor (HEMT), a heterojunction bipolar transistor (HBT), or the like can also be applied.

  The horn opening 80 is composed of an open horn antenna. The opening angle θ of the horn opening is desirably set to about 10 degrees or less, for example, in order to provide directivity in the radiation direction of the electromagnetic wave (hν). The length L3 of the horn opening 80 is, for example, about 700 μm or less. The opening width at the tip of the horn opening 80 is, for example, about 160 μm.

  The waveguide 70 is disposed in the opening of the resonator 60. The length L2 of the waveguide 70 is, for example, about 700 μm or less. In addition, the distance between the first electrode 4 and the second electrode 2 in the waveguide 70 is, for example, about 24 μm.

  The horn shape of the horn opening 80 is a structure necessary for extracting electromagnetic waves into the air. Due to the horn shape, electromagnetic waves can be efficiently extracted into the air with good impedance matching. The shape of the horn is not limited to a linear shape, but may be a non-linear shape, a curved shape, a quadratic curved shape, a parabolic shape, a stepped shape, or the like.

  In the resonator 60, two concave portions 5 and 6 are formed, and a convex portion 7 is formed between the two concave portions 5 and 6. Then, a protrusion 8 is formed at a substantially central portion of the convex portion 7 of the second electrode 2, and an active element 90 is disposed below the protrusion 8 so as to be sandwiched between the first electrode 4 a. .

The length L1 of the resonator 60 is, for example, about 30 μm or less. The length of the protrusion 8 is, for example, about 6 μm or less. Further, the width of the recesses 5 and 6 (the distance between the first electrode 4 and the second electrode 2) is, for example, about 4 μm. The dimension of the active element 90 is, for example, about 1.4 μm ² . However, the size of the active element 90 is not limited to this value, and may be, for example, about 5.3 μm ² or less. The detailed structure of the active element 90 will be described later. The size of each part of the resonator 60 is not limited to the above dimensions, and is appropriately set in design according to the frequency of the oscillating electromagnetic wave.

  Further, as shown in FIG. 1, compared with the distance between the first electrode 4 and the second electrode 2 in the waveguide 70, the first electrode 4 and the second electrode in the portion where the resonator 60 is formed. The interval between the electrodes 2 is narrow.

  The MIM reflector 50 is disposed at the closing portion on the opposite side of the opening of the resonator 60. Due to the laminated structure of the metal / insulator / metal MIM reflector 50, the first electrode 4 and the second electrode 2 are short-circuited in high frequency. Further, the MIM reflector 50 has an effect that it can reflect a high frequency while being open in terms of direct current.

  Each of the first electrode 4 (4a, 4b, 4c) and the second electrode 2, 2a has, for example, a metal laminated structure of Au / Pd / Ti, and the Ti layer is a semi-insulating InP substrate described later. It is a buffer layer for making the contact state with the semiconductor substrate 1 which consists of favorable. The thickness of each part of the first electrodes 4a, 4b, 4c and the second electrodes 2, 2a is, for example, about several hundred nm, and as a whole, as shown in FIGS. 3 (a) and 3 (b). A flattened laminated structure is obtained. Note that both the first electrode 4 and the second electrode 2 can be formed by a vacuum evaporation method, a sputtering method, or the like.

  More specifically, the first electrode 4a and the first electrode 4c are made of, for example, Au / Pd / Ti, and the first electrode 4b is made of, for example, Au / Ti. The second electrode 2 is made of, for example, Au / Pd / Ti, and the second electrode 2a is made of, for example, Au / Ti.

  Note that the Ti layer forming the surface layer of the first electrode 4b is desirably removed in order to reduce the contact resistance when the extraction electrode is formed by the bonding wire 12b. Similarly, the Ti layer forming the surface layer of the second electrode 2a is desirably removed in order to reduce the contact resistance when the extraction electrode is formed by the bonding wire 12a.

The insulating layer 3 can be formed of, for example, a SiO ₂ film. In addition, a Si ₃ N ₄ film, a SiON film, a HfO ₂ film, an Al ₂ O ₃ film, or the like can be applied. The thickness of the insulating layer 3 can be determined in consideration of the geometric plane size of the MIM reflector 50 and the required capacitor value in terms of circuit characteristics, and is, for example, about several tens nm to several hundreds nm. . The insulating layer 3 can be formed by a chemical vapor deposition (CVD) method, a sputtering method, or the like.

Similarly, the interlayer insulating film 9 can be formed of, for example, a SiO ₂ film. In addition, a Si ₃ N ₄ film, a SiON film, a HfO ₂ film, an Al ₂ O ₃ film, or the like can be applied. As shown in FIG. 4A, the thickness of the interlayer insulating film 9 is such that the total thickness of the second electrode 2 and the interlayer insulating film 9 is approximately the same as the thickness of the first electrode 4. Is set to The interlayer insulating film 9 can be formed by a CVD method or a sputtering method.

  The insulator substrate 10 is preferably made of a substrate having a lower dielectric constant than the semiconductor layer 91a in order to efficiently extract radio waves. As the insulating substrate 10 made of a low dielectric constant material, for example, a polyimide resin substrate, a Teflon (registered trademark) substrate, or the like can be applied. The thickness of the insulator substrate 10 is, for example, about 200 μm.

In the terahertz oscillation device according to the first embodiment, since the upper side is air, the relative dielectric constant ε _air = 1. When a polyimide resin substrate is used as the insulator substrate 10, since the relative permittivity ε _poly = 3.5 of the polyimide resin, the ratio of the oscillation output below the insulator substrate 10 to the total oscillation output is ε _poly ^3/2 / (ε _air ^3/2 + ε _poly ^3/2 ) = 0.87. That is, about 87% of the total oscillation output is radiated to the insulator substrate 10 side, and the oscillation output radiated laterally from the horn opening 80 is relatively increased.

Further, when a Teflon (registered trademark) resin substrate is used as the insulator substrate 10, since the relative permittivity ε _tef of the Teflon (registered trademark) is 2.1, the insulator substrate 10 is directed downward with respect to the entire oscillation output. The ratio of the oscillation output is represented by ε _tef ^3/2 / (ε _air ^3/2 + ε _tef ^3/2 ) = 0.75. That is, about 75% of the total oscillation output is radiated to the insulator substrate 10 side, and the oscillation output radiated laterally from the horn opening 80 is relatively increased.

As shown in FIG. 3A, the MIM reflector 50 is formed from a structure in which an insulating layer 3 is interposed between the first electrode 4 a and the second electrode 2. As is clear from FIG. 3B, the active element 90 made of RTD is disposed on the insulator substrate 10 via the first electrode 4a. The first electrode 4a is disposed in contact with the n ⁺ GaInAs layer 91b of the RTD. The second electrode 2 is disposed in contact with the n ⁺ GaInAs layer 91a of the RTD. Further, the first electrode 4 (4b, 4c) is disposed so as to extend on the insulator substrate 10.

Thus, since the 1st electrode 4 is extended and arrange | positioned on the insulator board | substrate 10, the 1st electrode 4 and the 2nd electrode 2 are not mutually short-circuited, but RTD. A predetermined DC bias voltage can be applied between the n ⁺ GaInAs layer 91a and the n ⁺ GaInAs layer 91b.

  Note that a bonding wire 12b is connected to the first electrode 4, a bonding wire 12a is connected to the second electrode 2a, and a DC power source is connected between the first electrode 4 and the second electrode 2a. 15 is connected. In addition, a resistor (not shown) for preventing parasitic oscillation is connected between the first electrode 4 and the second electrode 2a.

  In the terahertz oscillation device according to the first embodiment, a schematic bird's-eye view structure after the step of attaching the insulator substrate 10 having the thickness d to the sample surface and removing the semiconductor substrate by etching is as shown in FIG. The schematic bird's-eye view structure represented from the back surface of FIG. 5 is represented as shown in FIG. As is clear from FIG. 5, the first electrode 4 is directly attached to the insulator substrate 10. Although not shown in FIG. 5, the second electrodes 2 and 2 a are attached to the insulator substrate 10 via the interlayer insulating film 9 as shown in FIG. 3. The detailed structure of FIG. 6 corresponds to FIG.

  In the terahertz oscillation device according to the first embodiment, a schematic bird's-eye view structure after the electrode pattern is formed on the semiconductor substrate 1 is expressed as shown in FIG. 7 and schematically along the line II in FIG. The cross-sectional structure is expressed as shown in FIG. 8A, and the schematic cross-sectional structure along the line II-II in FIG. 7 is expressed as shown in FIG.

  In the terahertz oscillation device according to the first embodiment, a schematic bird's-eye view structure after the electrode pattern is formed on the semiconductor substrate 1 is formed on the semiconductor substrate 1 and the semiconductor substrate 1 as shown in FIGS. Second electrode 2, 2 a arranged, insulating layer 3 arranged on second electrode 2, arranged on insulating substrate 3 with respect to second electrode 2, and on semiconductor substrate 1 A first electrode 4 (4a, 4b, 4c) disposed opposite to the second electrode 2 and an MIM reflector 50 formed between the first electrode 4a and the second electrode 2 with the insulating layer 3 interposed therebetween. A resonator 60 disposed between the first electrode 4 and the second electrode 2 facing the semiconductor substrate 1 adjacent to the MIM reflector 50, and an active disposed at a substantially central portion of the resonator 60. Adjacent to the element 90 and the resonator 60, the first electrode 4 and the first electrode facing the semiconductor substrate 1. A waveguide 70 arranged between the two electrodes 2, a first electrode 4 facing the semiconductor substrate 1 adjacent to the waveguide 70, and a horn opening 80 arranged between the second electrodes 2. Prepare.

  The schematic cross-sectional structure of the comparative example corresponding to FIG. 8A is represented as shown in FIG. 9A, and the schematic cross-sectional structure of the comparative example corresponding to FIG. ).

  In the structure of the comparative example, the insulator substrate 10 was pasted directly on the first electrode 4 and on the second electrode 2 via the interlayer insulating film 9, and the semiconductor substrate 1 was removed by etching and then turned upside down. The structure is represented as shown in FIGS. 4 (a) and 4 (b). As shown in FIG. 4A and FIG. 4B, in the comparative example, the semiconductor layer 91a is disposed on the second electrode 2, so that the second electrode 2 is wire bonded. In order to perform the electrode extraction process such as the above, a process of patterning the semiconductor layer 91a is required. Alternatively, in the structure of FIG. 9A, after the insulator substrate 10 is directly pasted on the first electrode 4 and the semiconductor substrate 1 is removed by etching, another insulator substrate is pasted again and the previous insulation is performed. If it is going to carry out the process of removing the body substrate 10, this process becomes difficult in terms of strength due to the thin film structure of the terahertz oscillation element.

  On the other hand, in the structure of the terahertz oscillation device according to the first embodiment, the insulator substrate 10 is pasted directly on the first electrode 4 and on the second electrode 2 via the interlayer insulating film 9. The structure upside down after the semiconductor substrate 1 is removed by etching is expressed as shown in FIGS. 3 (a) and 3 (b). As shown in FIGS. 3A and 3B, in the first embodiment, the semiconductor layer 91a is disposed on the second electrode 2, but the second electrode 2a is also exposed. In addition, an electrode extraction process such as wire bonding can be easily performed on the second electrode 2a.

(Manufacturing process)
In the method for manufacturing the terahertz oscillation device according to the first embodiment, as shown in FIGS. 8A and 8B, after the semiconductor layer 91a is formed on the semiconductor substrate 1, the semiconductor layer 91a is patterned by patterning. The width is narrowed, and the pattern width of the second electrode 2 formed on the semiconductor layer 91a is narrowed. In the remaining portion, a second electrode 2a is formed which is connected to the second electrode 2 and has a predetermined width and is relatively thick. As a result, as shown in FIGS. 8A and 8B, a structure in which the second electrode 2a is in contact with the semiconductor substrate 1 is obtained.

  Next, as shown in FIG. 3A and FIG. 3B, the insulator substrate 10 is pasted directly on the first electrode 4 and on the second electrode 2 via the interlayer insulating film 9, A vertically inverted structure after the semiconductor substrate 1 is removed by etching is obtained.

  Next, as shown in FIG. 1, the bonding wire 12b is connected to the first electrode 4, and the bonding wire 12a is connected to the second electrode 2a, whereby the electrode is taken out.

  The semiconductor substrate 1 is formed of, for example, a semi-insulating InP substrate and has a thickness of about 600 μm, for example. As the etching solution for the InP substrate, for example, a hydrochloric acid-based etching solution can be applied.

(Resonant tunnel diode)
A schematic cross-sectional structure of the active element 90 used in the terahertz oscillation element according to the first embodiment is expressed as shown in FIG. FIG. 10 shows an example of a structure disposed on the semiconductor substrate 1. After the insulator substrate 10 is attached to the first electrode 4 a in a subsequent process, the semiconductor substrate 1 is removed by etching. Therefore, FIG. 10 corresponds to a schematic cross-sectional structure in the vicinity of the active element 90 before the step of attaching the insulator substrate 10.

  As shown in FIG. 10, a configuration example of an RTD as an active element 90 used in the terahertz oscillation element according to the first embodiment is arranged on a semiconductor substrate 1 made of a semi-insulating InP substrate, and is an n-type impurity. Heavily doped GaInAs layer 91a, GaInAs layer 92a doped with n-type impurities, undoped GaInAs layer 93b, GaInAs layer 93b disposed on GaInAs layer 92a An RTD portion composed of an AlAs layer 94a / GaInAs layer 95 / AlAs layer 94b disposed above, an undoped GaInAs layer 93b disposed on the AlAs layer 94b, and an n-type impurity disposed on the GaInAs layer 93a Doped on the GaInAs layer 92b and the GaInAs layer 92b, the n-type non- A GaInAs layer 91b doped with a pure substance at a high concentration, a first electrode 4a disposed on the GaInAs layer 91b, and a second electrode 2 disposed on the GaInAs layer 91a are provided.

As shown in FIG. 10, the RTD portion is formed by sandwiching a GaInAs layer 95 between AlAs layers 94a and 94b. The RTD portion laminated in this way is provided with the second n-type GaInAs layers 92a and 92b and the n ⁺ -type GaInAs layers 91a and 91b with the undoped GaInAs layers 93a and 93b used as spacers interposed therebetween. The electrode 2 and the first electrode 4 are ohmicly connected.

  Here, the thickness of each layer is as follows, for example.

The thicknesses of the n ⁺ -type GaInAs layers 91a and 91b are, for example, about 400 nm and about 30 nm, respectively. The n-type GaInAs layers 91a and 91b are substantially equal in thickness, for example, about 50 nm. The undoped GaInAs layers 93a and 93b are substantially equal in thickness, for example, about 5 nm. The thicknesses of the AlAs layers 94a and 94b are equal, for example, about 1.5 nm. The thickness of the GaInAs layer 95 is about 4.5 nm, for example.

Note that an insulating film made of a SiO ₂ film, a Si ₃ N ₄ film, a SiON film, a HfO ₂ film, an Al ₂ O ₃ film, or a multilayer film thereof is deposited on the side wall portion of the laminated structure shown in FIG. You can also. The insulating layer can be formed by a CVD method, a sputtering method, or the like.

The dimension of the RTD constituting the active element 90 is, for example, about 1.4 μm ² or less. For example, the oscillation frequency observed at room temperature is about 460 GHz. Further, for example, the current density Jp of the terahertz oscillation element at the time of oscillation is about 7 mA / μm ² .

(Electromagnetic field simulation results)
An example of a three-dimensional electromagnetic field simulation result in the XYZ-axis direction of the terahertz oscillation device according to the first embodiment is expressed as shown in FIG. 11, and the electric field pattern on the XY plane corresponding to FIG. The simulation result is expressed as shown in FIG. It can be seen that the Y-axis direction is the output direction of radio waves, and extremely good directivity is obtained. In the example of FIG. 11, in the terahertz oscillation device according to the first embodiment shown in FIGS. 5 and 6, the insulator substrate 10 is formed of a polyimide substrate having a thickness d = 200 nm, and the oscillation frequency f = 0. The result is 5 THz.

(Circuit configuration)
The schematic circuit configuration of the terahertz oscillation device according to the first embodiment is represented by a parallel circuit of a diode that configures the active device 90 and a capacitor CM that configures the MIM reflector 50, as shown in FIG. Is done. A diode cathode is connected to the first electrode 4, a diode anode is connected to the second electrode 2, a negative voltage is applied to the first electrode 4, and a positive voltage is applied to the second electrode 2. Is applied. In the oscillation state, the electromagnetic wave (hν) is propagated with good directivity in the Y-axis direction that is the opening direction of the horn opening.

An equivalent circuit configuration of the terahertz oscillation device according to the first embodiment corresponding to 13 (a) is expressed as shown in FIG. 13 (b). As shown in FIG. 13B, the RTD constituting the active element 90 can be represented by a parallel circuit of a capacitor C01 and an inductor L01. Since the capacitor CM of the MIM reflector 50 is further connected in parallel, the terahertz electromagnetic wave The oscillation frequency f of (hν) is represented by f = 1 / [2π (L01 (C01 + CM) ^1/2 ).

(Modification)
The electrode pattern structure of the terahertz oscillation device according to the first modification of the first embodiment is schematically represented as shown in FIG. 14A, and the electrode pattern structure of the terahertz oscillation device according to the second modification is It is schematically represented as shown in FIG.

  The electrode pattern structure of the terahertz oscillation element according to the modification 1 is an example in which the second electrode 2 constituting the MIM reflector 50 is provided with a stub structure, and the electrode pattern structure of the terahertz oscillation element according to the modification 2 is an MIM reflector. This is an example in which the first electrode 4 constituting 50 is provided with a stub structure. As apparent from FIG. 3A, since the semiconductor layer 91a is disposed on the second electrode 2, in FIG. 14A and FIG. 14B, the semiconductor layer 91a is displayed. However, the pattern of the second electrode 2 is arranged in the same pattern shape under the semiconductor layer 91a.

  That is, as shown in FIG. 14A, the second electrode 2 includes a plurality of stubs 13 </ b> A in a portion constituting the MIM reflector 50.

  Further, as shown in FIG. 14B, the first electrode 4 includes a plurality of stubs 13 </ b> B in a portion constituting the MIM reflector 50.

  The plurality of stubs 13A or 13B may be arranged at equal intervals facing the resonator 60, or may be arranged so that the intervals thereof change.

  A combination of Modification 1 and Modification 2 may include a plurality of stubs on both the second electrode 2 and the first electrode 4.

  A resonant circuit is formed by providing a stub with a quarter of the wavelength of the electromagnetic wave in a part of the transmission line of the electromagnetic wave, drawing the electromagnetic wave into the stub, reflecting it, and returning it to the transmission line. I know. This is because only the electromagnetic wave having a wavelength four times the length of the stub out of the electromagnetic wave incident on the transmission line is equivalently short-circuited at the position of the stub, and this electromagnetic wave is reflected thereby. This is a phenomenon that leakage from the transmission line is reduced. According to this method, since the length of the stub is determined to be a quarter wavelength with respect to the wavelength of the input electromagnetic wave, for the electromagnetic wave in which the wavelength of the electromagnetic wave is four times the length of the stub. Although it can be strongly resonated and reflected, an electromagnetic wave having a wide bandwidth has little reflection effect.

  The length of the stub 13A of the first modification of the first embodiment is not a quarter wavelength of the electromagnetic wave at the center of the incident electromagnetic wave having a band, but is shifted from the quarter. . For example, when there is a frequency width to be reflected, it is desired to reflect by providing many stubs 13A having a length of 2 to 3 wavelengths for partially reflecting electromagnetic waves having a median frequency of the frequency width. It is possible to reflect electromagnetic waves having a frequency range in a wide range.

  Naturally, the reflectivity of the electromagnetic wave is smaller than that of the quarter wavelength, but still a considerable amount of reflection occurs compared to the case where there is no stub. And, there is an effect of uniformly reflecting a frequency having a certain band (electromagnetic wave having a certain wavelength width) as much as the resonance condition is loose. In addition, the multi-stage stub spacing is about half the wavelength of electromagnetic waves having a median frequency of the frequency width of the electromagnetic waves to be reflected. Reflection) occurs, the reflected waves are superimposed, and the reflectance becomes a large value of almost 100%. Depending on the length, number, and interval of the stubs, the reflected frequency width and the center frequency are comprehensively determined.

₀ the center wavelength of the electromagnetic wave lambda having a predetermined bandwidth, and the distance of the stub and lambda _0/2, the reflectivity can be obtained a wavelength range Δλ of electromagnetic waves close to 100%. At this time, the length of the stub, it is preferable to design the 2～3Ramuda ₀ or more. Further, when the width of the stub is half of the stub interval, a large reflectance close to 100% is obtained with a small number of about 5 to 10 stubs. When the stub width is other than that, it is necessary to increase the number of stubs in order to obtain a large reflectance, and the frequency width is also narrowed. However, these lengths are not limited and are defined in terms of design in relation to the reflected bandwidth.

  In the first modification of the first embodiment, the leaked electromagnetic wave transmitted to the closing portion side is reflected by the stub 13A and the MIM reflector and returned to the opening side. And since the reflected electromagnetic waves are radiated | emitted as an output, the electromagnetic waves oscillated from the active element 90 become a high output.

  Also in the second modification of the first embodiment, the operation of the stub 13B is the same as that of the stub 13A, and thus a duplicate description is omitted.

  By providing multistage stubs on both the second electrode 2 and the first electrode 4, it is possible to obtain the same large reflectivity with about half the number of stubs as compared with the case of only one. In addition, the degree of freedom in design when determining the frequency width and center frequency can be increased, which is extremely effective in design. Note that the length, number, and interval of the stubs attached to both the second electrode 2 and the first electrode 4 are not necessarily equal, and can be freely changed in design.

  According to the terahertz oscillation device according to the first embodiment, the directivity in the lateral direction is improved by using the low dielectric constant insulator substrate, and the directivity is directed in the lateral direction with respect to the substrate with high efficiency and high output. It can oscillate with high performance and can be easily integrated.

  According to the terahertz oscillation device according to the modification of the first embodiment, the directivity in the lateral direction is improved by using the low dielectric constant insulating substrate, and the stub structure is combined with the electrodes constituting the MIM reflector. Thus, it becomes possible to extract electromagnetic waves more efficiently in the direction horizontal to the substrate and with higher directivity.

(Second Embodiment)
A schematic planar configuration of the electrode pattern structure of the terahertz oscillation device according to the second embodiment is expressed as shown in FIG.

  Also in the terahertz oscillation device according to the second embodiment, the configurations of the first electrode 4 (4a, 4b, 4c), the second electrode 2, 2a, the MIM reflector 50, the resonator 60, and the active element 90 are as follows. Since this is the same as that of the first embodiment, the redundant description will be omitted below.

  As shown in FIG. 15, the terahertz oscillation device according to the second embodiment includes an insulator substrate 10, a first electrode 4 (4 a, 4 b, 4 c) disposed on the insulator substrate 10, An insulating layer 3 (FIG. 3) disposed on one electrode 4a (FIG. 3), an interlayer insulating film 9 (FIG. 3) disposed on the insulator substrate 10, and an interlayer insulating film 9. In addition, the second electrodes 2 and 2a disposed opposite the first electrode 4 with respect to the first electrode 4a through the insulating layer 3, and the semiconductor layer 91a disposed on the second electrode 2; A first slot line electrode 41 disposed on the insulator substrate 10 adjacent to the first electrode 4 and opposite the first electrode 4 on the opposite side of the second electrode 2a; 10 and a second slot disposed adjacent to the second electrode 2a and opposite the first electrode 4 on the opposite side of the second electrode 2a. The line electrode 21, the MIM reflector 50 formed between the first electrode 4 a and the second electrode 2 with the insulating layer 3 interposed therebetween, and the first electrode which is adjacent to the MIM reflector 50 and faces the insulator substrate 10. The resonator 60 disposed between the electrode 4 and the second electrode 2, the active element 90 disposed substantially at the center of the resonator 60, and the resonator 60 are adjacent to each other on the insulator substrate 10. A first waveguide 70 disposed between the first electrode 4 and the second electrode 2, and the first electrode 4 and the second electrode adjacent to the first waveguide 70 and opposed to the insulator substrate 10. A first horn opening 80 disposed between the electrodes 2, a second waveguide 71 disposed between the first electrode 4 and the first slot line electrode 41 opposed to each other on the insulator substrate 10, and a second conductor. Adjacent to the waveguide 71, the first electrode 4 and the first slot line electrode facing the insulator substrate 10 are opposed to each other. 41, a second horn opening 81, a second waveguide 2a facing the insulator substrate 10, and a third waveguide 72 disposed between the second slot line electrodes 21, and a third waveguide. 72, the second electrode 2 a facing the insulator substrate 10 and the third horn opening 82 disposed between the second slot line electrodes 21 are provided.

  As in the first embodiment, the active element 90 is typically an RTD, but other diodes or transistors may be used. As other active elements, for example, TUNETTT diodes, IMPATT diodes, GaAsFETs, GaN-based FETs, HEMTs, HBTs, and the like can be applied.

  The horn openings 80 to 82 constitute an open horn antenna.

  In the terahertz oscillation device according to the second embodiment, as shown in FIG. 15, the width W4 of the slot line electrodes 21 and 41 at the output end is, for example, about 160 μm. As shown in FIG. 15, the width D20 of the horn opening 80, the width D10 of the horn openings 81 and 82, and the width W4 of the slot line electrodes 21 and 41 at the output end can be changed as appropriate.

  The waveguide 70 is disposed in the opening of the resonator 60.

  The MIM reflector 50 is disposed in a closed portion opposite to the opening of the resonator 60.

  In the portion constituting the MIM reflector 50, the second electrode 2 may include a plurality of stubs similar to those of the first modification of the first embodiment shown in FIG.

  Similarly, in the portion constituting the MIM reflector 50, the second electrode 2 may include a plurality of stubs similar to those of the second modification of the first embodiment shown in FIG. .

  In the above description, the plurality of stubs may be arranged at equal intervals facing the resonator 60, or may be arranged so that the intervals change.

  The insulator substrate 10 is preferably made of a substrate having a lower dielectric constant than that of the semiconductor layer 91a in order to extract radio waves efficiently in the lateral direction and with high directivity. As the insulator substrate 10 made of a low dielectric constant material, for example, a polyimide resin substrate, a Teflon (registered trademark) substrate, or the like can be applied as in the first embodiment.

  When a polyimide resin substrate is used as the insulator substrate 10, about 87% of the total oscillation output is radiated to the insulator substrate 10 side, and the oscillation output radiated laterally from the horn opening 80 is relative. The point which increases automatically is the same as that of the first embodiment.

  Further, when a Teflon (registered trademark) resin substrate is used as the insulator substrate 10, about 75% of the entire oscillation output is radiated to the insulator substrate 10 side as in the first embodiment, The oscillation output radiated from the horn opening 80 in the lateral direction is the same as that of the first embodiment in that the oscillation output is relatively increased.

  In the terahertz oscillation device according to the second embodiment, the taper-shaped 1 having the same shape is formed on both sides of the taper slot antenna including the first electrode 4 and the second electrode 2 connected to the active device 90. By arranging the pair of slot line electrodes 41 and 21, the directivity is further improved as compared with the first embodiment.

  According to the terahertz oscillation device according to the second embodiment, a pair of tapered slot line electrodes 41 and 21 are arranged in parallel on both sides of the tapered slot antenna including the first electrode 4 and the second electrode 2. By arranging them in a uniform manner, even if the tapered slot antenna is integrated on the insulator substrate 10, the influence of the insulator substrate 10 can be suppressed and sufficient directivity can be obtained.

  The electric field spread from the tapered slot antenna composed of the first electrode 4 and the second electrode 2 in the center is drawn into a pair of slot line electrodes 41, 21 provided on both sides, and the slot line electrodes 41, 21 And is returned to the first electrode 4 and the second electrode 2 at the center. At this time, a standing wave is formed in the first electrode 4 and the second electrode 2 and the slot line electrodes 41 and 21 in the central portion, and electromagnetic waves are radiated to the outside by the reflected electric field. Directivity is improved by the interference of the electromagnetic fields radiated from the center first electrode 4 and second electrode 2 and the pair of slot line electrodes 41 and 21.

  According to the terahertz oscillation device according to the second embodiment, the directivity in the lateral direction is improved by using an insulating substrate having a low dielectric constant, and the standing wave is effectively arranged by arranging the slot line electrodes in parallel. Therefore, it is possible to oscillate with high directivity in the lateral direction with respect to the substrate with high efficiency and high output, and integration is easy.

(Third embodiment)
A schematic planar configuration of the electrode pattern structure of the terahertz oscillation device according to the third embodiment is expressed as shown in FIG.

  Also in the terahertz oscillation device according to the third embodiment, the first electrode 4, the second electrode 2, the MIM reflector 50, the resonator 60, the active device 90, the first slot line electrode 41, the second slot line Since the configuration of the electrode 21 is the same as that of the second embodiment, a redundant description is omitted below.

  As shown in FIG. 16, the terahertz oscillating device according to the third embodiment has a pair of slot line electrodes 22, 42 in addition to the electrode pattern configuration of the second embodiment shown in FIG. Is characterized by the fact that these are arranged in parallel. That is, the third slot line electrode 42 disposed on the insulator substrate 10 adjacent to the first slot line electrode 41 and opposite to the first electrode 4 and facing the first slot line electrode 41; A fourth slot line electrode 22 disposed adjacent to the second slot line electrode 21 on the insulator substrate 10 and opposite to the second slot line electrode 21 on the opposite side of the second electrode 2a; A fourth waveguide 74 disposed between the first slot line electrode 41 and the third slot line electrode 42 facing on the substrate 10, and a first waveguide facing the insulator substrate 10 adjacent to the fourth waveguide 74. A fourth horn opening 84 disposed between the first slot line electrode 41 and the third slot line electrode 42, and between the second slot line electrode 21 and the fourth slot line electrode 22 facing on the insulator substrate 10. The fifth waveguide 73 disposed and the fifth horn opening disposed between the second slot line electrode 21 and the fourth slot line electrode 22 facing the insulator substrate 10 adjacent to the fifth waveguide 73. Part 83.

  The insulator substrate 10 is preferably made of a substrate having a lower dielectric constant than that of the semiconductor layer 91a in order to extract radio waves efficiently in the lateral direction and with high directivity. As the insulator substrate 10 made of a low dielectric constant material, for example, a polyimide resin substrate, a Teflon (registered trademark) substrate, or the like can be applied as in the first embodiment.

  In the configuration of FIG. 16, the oscillation frequency is 0.64 THz, and the directivity is further improved by arranging a pair of slot line electrodes 22 and 42 in parallel outside the slot line electrodes 21 and 41. To do.

  According to the terahertz oscillating device according to the third embodiment, the lateral directivity is improved by using an insulating substrate having a low dielectric constant, and two pairs of slot line electrodes are arranged in parallel. By effectively generating the wave, it is possible to oscillate with high directivity in the lateral direction with respect to the substrate with higher efficiency and higher output, and integration is easy.

[Other embodiments]
As described above, the present invention has been described according to the first embodiment and its modifications, and the second and third embodiments. However, the description and the drawings that form a part of this disclosure are exemplary. It should not be understood as limiting the invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  In the second embodiment and the third embodiment, there is disclosed an example in which a standing wave is effectively generated by arranging one or two pairs of slot line electrodes in parallel. Further, a plurality of pairs of three or more pairs may be arranged.

  As described above, the present invention includes various embodiments not described herein.

  The terahertz oscillation device of the present invention is an oscillation / amplification device that operates in the frequency region of the THz band. In addition to THz imaging, large-capacity communication / information processing, measurement in various fields such as physical properties, astronomy, and organisms, security field, etc. Can be applied to a wide range of fields.

DESCRIPTION OF SYMBOLS 1 ... Semiconductor substrate 2, 2a ... 2nd electrode 3 ... Insulating layer 4, 4a, 4b, 4c ... 1st electrode 5, 6 ... Concave part 7 ... Convex part 8 ... Protrusion part 9 ... Interlayer insulating film 10 ... Insulator Substrate 13A, 13B ... Stub 15 ... DC power supply 21, 22, 41, 42 ... Slot line electrode 50 ... MIM reflector 60 ... Resonator 70, 71, 72, 73, 74 ... Waveguide 80, 81, 82, 83, 84 ... Horn opening 90 ... Active element 91a ... Semiconductor layer

Claims (20)

An insulator substrate;
A first electrode disposed on the insulator substrate;
An insulating layer disposed on the first electrode;
An interlayer insulating film disposed on the insulator substrate;
A second electrode disposed on the interlayer insulating film and disposed opposite to the first electrode via the insulating layer with respect to the first electrode;
A semiconductor layer disposed on the second electrode;
An MIM reflector formed between the first electrode and the second electrode across the insulating layer;
A resonator disposed between the first electrode and the second electrode facing the insulator substrate adjacent to the MIM reflector;
An active element disposed substantially in the center of the resonator;
A waveguide disposed between the first electrode and the second electrode facing the insulator substrate adjacent to the resonator;
An oscillating device comprising: a horn opening disposed between the first electrode and the second electrode facing the insulator substrate adjacent to the waveguide.   2. The oscillation element according to claim 1, wherein the active element is a resonant tunneling diode.   The oscillating device according to claim 1, wherein the horn opening constitutes an open horn antenna.   The oscillation element according to claim 1, wherein the waveguide is disposed in an opening of the resonator.   The oscillating device according to claim 1, wherein the MIM reflector is disposed in a closed portion opposite to the opening of the resonator.   6. The oscillation element according to claim 1, wherein the second electrode includes a plurality of stubs in a portion constituting the MIM reflector.   The oscillation element according to claim 1, wherein the first electrode includes a plurality of stubs in a portion constituting the MIM reflector.   The oscillating device according to claim 6, wherein the plurality of stubs are arranged at equal intervals facing the resonator. 8. The oscillation element according to claim 6, wherein the plurality of stubs are arranged so as to face the resonator and the distance between the stubs changes. 9.   The distance between the first electrode and the second electrode in the part where the resonator is formed is narrower than the distance between the first electrode and the second electrode in the waveguide. The oscillating device according to claim 1, wherein the oscillating device is an oscillating device.   11. The oscillation element according to claim 1, wherein the insulator substrate is made of a substrate having a dielectric constant lower than that of the semiconductor layer. An insulator substrate;
A first electrode disposed on the insulator substrate;
An insulating layer disposed on the first electrode;
An interlayer insulating film disposed on the insulator substrate;
A second electrode disposed on the interlayer insulating film and disposed opposite to the first electrode via the insulating layer with respect to the first electrode;
A semiconductor layer disposed on the second electrode;
A first slot line electrode disposed on the insulator substrate adjacent to the first electrode and opposite to the second electrode and facing the first electrode;
A second slot line electrode disposed on the insulator substrate adjacent to the second electrode and opposite to the first electrode and facing the second electrode;
An MIM reflector formed between the first electrode and the second electrode across the insulating layer;
A resonator disposed between the first electrode and the second electrode facing the insulator substrate adjacent to the MIM reflector;
An active element disposed substantially in the center of the resonator;
A first waveguide disposed between the first electrode and the second electrode facing the insulator substrate adjacent to the resonator;
A first horn opening disposed between the first electrode and the second electrode facing the insulator substrate adjacent to the first waveguide;
A second waveguide disposed between the first electrode and the first slot line electrode facing each other on the insulator substrate;
A second horn opening disposed between the first electrode and the first slot line electrode facing the insulator substrate adjacent to the second waveguide;
A third waveguide disposed between the second electrode and the second slot line electrode facing each other on the insulator substrate;
An oscillation element comprising: the second electrode facing the insulator substrate, and a third horn opening disposed between the second slot line electrodes, adjacent to the third waveguide. .   The oscillation element according to claim 12, wherein the active element is a resonant tunneling diode.   The oscillating device according to claim 12 or 13, wherein the first horn opening, the second horn opening, and the third horn opening constitute an opening horn antenna.   The oscillation element according to claim 12, wherein the first waveguide is disposed in an opening of the resonator.   The oscillating device according to claim 12, wherein the MIM reflector is disposed in a closed portion opposite to the opening of the resonator.   17. The oscillation element according to claim 12, wherein the second electrode includes a plurality of stubs in a portion constituting the MIM reflector.   18. The oscillation element according to claim 12, wherein the first electrode includes a plurality of stubs in a portion constituting the MIM reflector. A third slot line electrode disposed on the insulator substrate adjacent to the first slot line electrode and opposite the first slot line electrode to face the first slot line electrode;
A fourth slot line electrode disposed adjacent to the second slot line electrode on the insulator substrate and opposite to the second slot line electrode on the opposite side of the second electrode;
A fourth waveguide disposed between the first slot line electrode and the third slot line electrode facing each other on the insulator substrate;
A fourth horn opening disposed between the first slot line electrode and the third slot line electrode facing the insulator substrate adjacent to the fourth waveguide;
A fifth waveguide disposed between the second slot line electrode and the fourth slot line electrode facing each other on the insulator substrate;
The fifth horn opening disposed between the second slot line electrode and the fourth slot line electrode facing the insulator substrate adjacent to the fifth waveguide. Item 13. The oscillation element according to Item 12.   20. The oscillation element according to claim 12, wherein the insulator substrate is made of a substrate having a dielectric constant lower than that of the semiconductor layer.