JP5987346B2 - Antenna, terahertz wave generation device, camera, imaging device, and measurement device - Google Patents

Description

  The present invention relates to an antenna, a terahertz wave generation device, a camera, an imaging device, and a measurement device.

In recent years, a terahertz wave, which is an electromagnetic wave having a frequency of 100 GHz or more and 30 THz or less, has attracted attention. The terahertz wave can be used for, for example, each measurement such as imaging and spectroscopic measurement, non-destructive inspection, and the like.
This terahertz wave generating device that generates a terahertz wave is irradiated with a light source device that generates a light pulse (pulse light) having a pulse width of about sub-p seconds (several hundreds of seconds), and a light pulse generated by the light source device. And an antenna that generates a terahertz wave.

  As the antenna, for example, Patent Document 1 discloses a pin structure photoconductive element (antenna) having an n-type semiconductor layer, an i-type semiconductor layer, and a p-type semiconductor layer. In this antenna, an n-type semiconductor layer is provided on one surface side of an i-type semiconductor layer, and a p-type semiconductor layer is provided on the other surface side. Further, the n-type semiconductor layer and the p-type semiconductor layer are arranged so as to be shifted from each other with respect to the thickness direction of the i-type semiconductor layer. The terahertz wave is emitted in a direction perpendicular to the direction of the electric field.

In the antenna described in Patent Document 1, the intensity of the generated terahertz wave is increased by about 10 times compared to a dipole photoconductive antenna (PCA) manufactured using a low-temperature grown GaAs (LT-GaAs) substrate. Can do.
However, in the antenna described in Patent Document 1, the n-type semiconductor layer is provided on one surface side of the i-type semiconductor layer, and the p-type semiconductor layer is provided on the other surface side. Depending on the thickness, the direction of the electric field changes, which causes a problem that the emission direction of the terahertz wave varies.

JP 2010-50287 A

  An object of the present invention is to provide an antenna, a terahertz wave generating device, a camera, an imaging device, and a measuring device that can generate a terahertz wave having a constant emission direction, high withstand voltage, and high strength.

  In order to solve the above-described problems, an antenna of the present invention is an antenna that generates a terahertz wave when irradiated with pulsed light, and is positioned on the substrate and on the substrate. And a first impurity-containing semiconductor layer composed of a semiconductor material containing a first conductivity type impurity, and a second impurity containing a semiconductor material containing a second conductivity type impurity different from the first conductivity type. The semiconductor layer, an i-type semiconductor layer made of an i-type semiconductor material that is located on the substrate and does not contain impurities of the first conductivity type and the second conductivity type, and the first impurity-containing semiconductor layer are electrically connected A first electrode electrically connected, and a second electrode electrically connected to the second impurity-containing semiconductor layer, and in plan view, the first impurity-containing semiconductor layer and the second impurity-containing semiconductor layer, Through a predetermined gap from each other Is location, the i-type semiconductor layer is characterized in that it is provided to fill the gap between the first impurity-containing semiconductor layer and the second impurity-containing semiconductor layer.

  According to this antenna, since an electric field is not applied to the surface of the i-type semiconductor layer having many crystal defects, the electric field is efficiently applied, whereby the withstand voltage is improved, and a larger electric field can be formed thereon. Intense terahertz waves can be generated. Furthermore, since the direction of the electric field becomes constant, the terahertz wave emission direction can be made constant.

  In the antenna of the present invention, the i-type semiconductor layer covers an end portion of the first impurity-containing semiconductor layer in contact with the gap and an end portion of the second impurity-containing semiconductor layer in contact with the gap. It is characterized by.

  According to this antenna, the leakage current flowing on the surface of the i-type semiconductor layer can be reduced, and the withstand voltage can be improved.

  In the antenna of the present invention, the substrate has a groove in a portion corresponding to the gap, and the i-type semiconductor layer is provided to fill the groove. Alternatively, the first impurity-containing semiconductor layer is provided with a concentration distribution so that the first impurity concentration increases from a lower surface in contact with the substrate toward an upper surface, and the second impurity-containing semiconductor layer is formed on the substrate. A concentration distribution is provided so that the second impurity concentration increases from the lower surface in contact with the upper surface toward the upper surface.

  According to the antenna having such a configuration, an electric field is not applied to the surface of the i-type semiconductor layer having many crystal defects and the interface between the i-type semiconductor layer and the substrate, and only inside the i-type semiconductor layer. Since an electric field can be applied to the electric field, the electric field can be applied more efficiently, thereby generating a terahertz wave having a higher intensity.

In the antenna of the present invention, the first electrode is provided on the first impurity-containing semiconductor layer, and a part of the first electrode and a part of the first impurity-containing semiconductor layer are in contact with each other. It is characterized by being.
According to such a configuration, the resistance can be reduced and the power consumption can be reduced.

In the antenna of the present invention, the second electrode is provided on the second impurity-containing semiconductor layer, and a part of the second electrode is in contact with a part of the second impurity-containing semiconductor layer. It is characterized by being.
According to such a configuration, the resistance can be reduced and the power consumption can be reduced.

The antenna according to the present invention further includes an insulating layer positioned between the i-type semiconductor layer and the substrate at at least a part of the gap.
Thereby, generation | occurrence | production of the leakage current in the gap | interval between a 1st impurity containing semiconductor layer and a 2nd impurity containing semiconductor layer can be prevented more reliably.

In the antenna of the present invention, the i-type semiconductor material is a III-V compound semiconductor.
Thereby, a terahertz wave having a higher intensity can be generated.

The terahertz wave generation device of the present invention includes a light source that generates pulsed light, and an antenna that generates terahertz waves when irradiated with the pulsed light generated by the light source, and the antenna includes a substrate; A first impurity-containing semiconductor layer located on the substrate and made of a semiconductor material containing an impurity of the first conductivity type; and a second conductivity type located on the substrate and different from the first conductivity type A second impurity-containing semiconductor layer made of a semiconductor material containing a plurality of impurities and an i-type semiconductor material located on the substrate and containing no impurities of the first and second conductivity types. A first semiconductor layer electrically connected to the first impurity-containing semiconductor layer, and a second electrode electrically connected to the second impurity-containing semiconductor layer. 1 impurity-containing semiconductor layer and the first The impurity-containing semiconductor layer is disposed with a predetermined gap therebetween, and the i-type semiconductor layer is provided to fill the gap between the first impurity-containing semiconductor layer and the second impurity-containing semiconductor layer. It is characterized by that.
With such a configuration, a terahertz wave generator having the effects of the present invention can be provided.

The camera of the present invention includes: a terahertz wave generator that generates a terahertz wave; and a terahertz wave detector that detects a terahertz wave that has been emitted from the terahertz wave generator and transmitted or reflected from an object. The generator includes a light source that generates pulsed light, and an antenna that generates terahertz waves when irradiated with the pulsed light generated by the light source. The antenna is located on the substrate and the substrate. And a semiconductor containing a first impurity-containing semiconductor layer made of a semiconductor material containing an impurity of the first conductivity type, and a second conductivity type impurity located on the substrate and different from the first conductivity type. A second impurity-containing semiconductor layer made of a material, and an i-type made of an i-type semiconductor material that is located on the substrate and does not contain impurities of the first conductivity type and the second conductivity type A conductor layer; a first electrode electrically connected to the first impurity-containing semiconductor layer; and a second electrode electrically connected to the second impurity-containing semiconductor layer. The impurity-containing semiconductor layer and the second impurity-containing semiconductor layer are disposed with a predetermined gap therebetween, and the i-type semiconductor layer is located between the first impurity-containing semiconductor layer and the second impurity-containing semiconductor layer. It is characterized by being provided by filling the gap.
With such a configuration, a camera having the effect of the present invention can be provided.

An imaging apparatus according to the present invention includes a terahertz wave generating apparatus that generates a terahertz wave, a terahertz wave detecting apparatus that detects a terahertz wave that is emitted from the terahertz wave generating apparatus and is transmitted or reflected by an object, and the terahertz wave detecting apparatus An image forming unit that generates an image of the object based on the detection result of the detection, and the terahertz wave generation device is irradiated with a light source that generates pulsed light and pulsed light generated by the light source An antenna that generates a terahertz wave, and the antenna includes a substrate, and a first impurity-containing semiconductor layer that is located on the substrate and is made of a semiconductor material containing an impurity of a first conductivity type. A second impurity-containing semiconductor layer made of a semiconductor material located on the substrate and containing an impurity of a second conductivity type different from the first conductivity type; An i-type semiconductor layer formed on an i-type semiconductor material which is located on the substrate and does not contain impurities of the first conductivity type and the second conductivity type; and a first electrically connected to the first impurity-containing semiconductor layer. One electrode and a second electrode electrically connected to the second impurity-containing semiconductor layer, and the first impurity-containing semiconductor layer and the second impurity-containing semiconductor layer are predetermined to each other in plan view. The i-type semiconductor layer is disposed via a gap, and is provided to fill the gap between the first impurity-containing semiconductor layer and the second impurity-containing semiconductor layer.
With such a configuration, an imaging apparatus having the effects of the present invention can be provided.

The measuring device of the present invention includes a terahertz wave generating device that generates a terahertz wave, a terahertz wave detecting device that detects a terahertz wave that is emitted from the terahertz wave generating device and is transmitted or reflected by an object, and the terahertz wave detecting device. A terahertz wave generating device, wherein the terahertz wave generating device includes a light source that generates pulsed light and a pulsed light generated by the light source. An antenna that generates a wave, and the antenna includes a substrate, a first impurity-containing semiconductor layer that is located on the substrate and is made of a semiconductor material containing an impurity of a first conductivity type, and the substrate A second impurity-containing semiconductor layer made of a semiconductor material containing an impurity of a second conductivity type different from the first conductivity type, and located on the substrate; An i-type semiconductor layer made of an i-type semiconductor material not containing impurities of the first conductivity type and the second conductivity type; a first electrode electrically connected to the first impurity-containing semiconductor layer; A second electrode electrically connected to the two impurity-containing semiconductor layers, and the first impurity-containing semiconductor layer and the second impurity-containing semiconductor layer are arranged with a predetermined gap therebetween in plan view. The i-type semiconductor layer is provided to fill the gap between the first impurity-containing semiconductor layer and the second impurity-containing semiconductor layer.
With such a configuration, a measuring apparatus having the effects of the present invention can be provided.

  With the above-described configuration, there is an effect that an antenna capable of generating a terahertz wave having a constant emission direction, a high breakdown voltage, and a high intensity can be realized. Thereby, a terahertz wave generator capable of emitting a high-intensity terahertz wave is realized. Therefore, there is a great effect that it is possible to provide a highly sensitive terahertz camera or imaging device and measurement device.

It is a figure showing a 1st embodiment of a terahertz wave generating device (antenna) of the present invention. It is a top view of the antenna of the terahertz wave generator shown in FIG. It is a top view which shows the modification of the antenna of the terahertz wave generator shown in FIG. It is a cross-sectional perspective view of the light source device of the terahertz wave generator shown in FIG. It is sectional drawing in the AA line in FIG. It is sectional drawing in the BB line in FIG. It is sectional drawing for demonstrating an example of the manufacturing method of the antenna of the terahertz wave generator shown in FIG. It is sectional drawing for demonstrating an example of the manufacturing method of the antenna of the terahertz wave generator shown in FIG. It is sectional drawing which shows 2nd Embodiment of the antenna of this invention. It is sectional drawing which shows 3rd Embodiment of the antenna of this invention. It is sectional drawing for demonstrating two examples of the manufacturing method of the antenna of 2nd Embodiment shown in FIG. 1 is a block diagram illustrating an embodiment of an imaging apparatus of the present invention. It is a top view which shows the terahertz wave detection apparatus of the imaging apparatus shown in FIG. It is a graph which shows the spectrum in the terahertz band of a target object. It is a figure of the image which shows distribution of substance A, B, and C of a target object. It is a block diagram which shows embodiment of the measuring device of this invention. It is a block diagram which shows embodiment of the camera of this invention.

  Hereinafter, an antenna, a terahertz wave generation device, a camera, an imaging device, and a measurement device of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.

<First Embodiment>
1 to 3 are diagrams showing a first embodiment of a terahertz wave generator (antenna) according to the present invention. 1 is a schematic diagram of a terahertz wave generator, FIG. 2 is a plan view of an antenna, and FIG. 3 is a plan view showing a modification of the antenna.
In FIG. 1, the antenna 2 is shown by a cross-sectional view taken along line SS in FIGS. 2 and 3, and the light source device 3 is shown by a block diagram. 4 is a cross-sectional perspective view of the light source device of the terahertz wave generator shown in FIG. 1, FIG. 5 is a cross-sectional view taken along line AA in FIG. 4, and FIG. 7 and 8 are cross-sectional views for explaining an example of a method for manufacturing the antenna 2 of the terahertz wave generating device 1 shown in FIG.

  As shown in FIG. 1, a terahertz wave generator 1 generates a terahertz wave by irradiating a light source device 3 that generates a light pulse (pulse light) that is excitation light and a light pulse generated by the light source device 3. And the antenna 2 to be used. The terahertz wave means an electromagnetic wave having a frequency of 100 GHz to 30 THz, particularly an electromagnetic wave of 300 GHz to 3 THz.

As shown in FIGS. 4 to 6, in the present embodiment, the light source device 3 is configured to perform optical pulse generation on the optical pulse generator 4 that generates an optical pulse and pulse compression on the optical pulse generated on the optical pulse generator 4. 1 pulse compression unit 5, a second pulse compression unit 7 that performs pulse compression on the optical pulse that has been subjected to pulse compression by the first pulse compression unit 5, and an amplification unit 6 that amplifies the optical pulse. doing.
The amplifying unit 6 is provided before the first pulse compressing unit 5 or between the first pulse compressing unit 5 and the second pulse compressing unit 7. In the illustrated configuration, the amplifying unit 6 includes The first pulse compression unit 5 and the second pulse compression unit 7 are provided.
As a result, the optical pulse that has been pulse-compressed by the first pulse compressor 5 is amplified by the amplifier 6, and the optical pulse that has been amplified by the amplifier 6 is pulse-compressed by the second pulse compressor 7. The

  The pulse width (half width) of the light pulse emitted from the light source device 3 is not particularly limited, but is preferably 1 f second or more and 800 f second or less, more preferably 10 f second or more and 100 f second or less.

  The frequency of the light pulse emitted from the light source device 3 is set to be equal to or higher than the frequency corresponding to the band gap of the i-type semiconductor layer 26 of the antenna 2 described later.

The optical pulse generator 4 may be a so-called semiconductor laser such as a DBR laser, a DFB laser, or a mode-locked laser. The pulse width of the optical pulse generated by the optical pulse generator 4 is not particularly limited, but is preferably 1 fsec or more and 800 fsec or less.
The first pulse compression unit 5 performs pulse compression based on saturable absorption. That is, the 1st pulse compression part 5 has a saturable absorber, compresses an optical pulse with the saturable absorber, and reduces the pulse width.

The second pulse compression unit 7 performs pulse compression based on group velocity dispersion compensation. That is, the first pulse compression unit 5 has a group velocity dispersion compensation medium, which in this embodiment has a coupled waveguide structure, and compresses the optical pulse by the coupled waveguide structure and reduces the pulse width. Let
In addition, the light pulse generation unit 4, the first pulse compression unit 5, the amplification unit 6, and the second pulse compression unit 7 of the light source device 3 are integrated, that is, integrated on the same substrate.

  Specifically, the light source device 3 is provided on a substrate 31 that is a semiconductor substrate, a cladding layer 32 provided on the substrate 31, an active layer 33 provided on the cladding layer 32, and the active layer 33. An etching stop layer 34 for the waveguide configuration process, a cladding layer 35 provided on the etching stop layer 34 for the waveguide configuration process, a contact layer 36 provided on the cladding layer 35, and an etching for the waveguide configuration process. The insulating layer 37 provided on the stop layer 34, the electrode 38 on the cladding layer 32 side provided on the surface of the substrate 31, and the cladding layer 35 side provided on the surfaces of the contact layer 36 and the insulating layer 37. Electrodes 391, 392, 393, 394, and 395. A diffraction grating 30 is provided between the waveguide stop process etching stop layer 34 of the optical pulse generator 4 and the cladding layer 35. Note that the waveguide structure process etching stop layer 34 is not limited to being directly above the active layer 33, and may be provided in the cladding layer 35, for example.

In addition, the constituent material of each part is not specifically limited. As an example of the constituent material, the substrate 31 and the contact layer 36 include GaAs or the like. Further, examples of the cladding layers 32 and 35, the waveguide stop process etching stop layer 34, and the diffraction grating 30 include AlGaAs.
Moreover, as the active layer 33, the structure using the quantum effect called a multiple quantum well is mentioned, for example. Specifically, as the active layer 33, a distributed refractive index type multiple quantum well composed of multiple quantum wells or the like in which a plurality of well layers (GaAs well layers) and barrier layers (AlGaAs barrier layers) are alternately provided. The thing of the structure called is mentioned.

  In the illustrated configuration, the waveguide in the light source device 3 includes a cladding layer 32, an active layer 33, a waveguide configuration process etching stop layer 34, and a cladding layer 35. The clad layer 35 is provided in a shape corresponding to the waveguide only on the waveguide. The clad layer 35 is formed by removing unnecessary portions by etching. Depending on the manufacturing method, the waveguide stop process etching stop layer 34 may be omitted.

  Two clad layers 35 and two contact layers 36 are provided. One clad layer 35 and contact layer 36 constitute a part of the optical pulse generator 4, the first pulse compressor 5, the amplifier 6, and the second pulse compressor 7, and are provided continuously. The other cladding layer 35 and contact layer 36 constitute a part of the second pulse compression unit 7. That is, the second pulse compression unit 7 is provided with a pair of cladding layers 35 and a pair of contact layers 36.

In addition, the electrode 391 is provided so as to correspond to the cladding layer 35 of the optical pulse generation unit 4, and the electrode 392 is provided so as to correspond to the cladding layer 35 of the first pulse compression unit 5, The electrode 393 is provided so as to correspond to the cladding layer 35 of the amplifying unit 6, and both the electrode 394 and the electrode 395 are provided so as to correspond to the two cladding layers 35 of the second pulse compression unit 7. ing. The electrode 38 is a common electrode for the optical pulse generator 4, the first pulse compressor 5, the amplifier 6, and the second pulse compressor 7. The electrode 38 and the electrode 391 constitute a pair of electrodes of the optical pulse generation unit 4, the electrode 38 and the electrode 392 constitute a pair of electrodes of the first pulse compression unit 5, The electrode 38 and the electrode 393 constitute a pair of electrodes of the amplifying unit 6, and the electrode 38 and the electrode 394, and the electrode 38 and the electrode 395 constitute two pairs of electrodes of the second pulse compression unit 7. .
In addition, although the whole shape of the light source device 3 has comprised the rectangular parallelepiped in the structure of illustration, it cannot be overemphasized that it is not limited to this.

  Moreover, although the dimension of the light source device 3 is not specifically limited, For example, it is 1 mm or more and 10 mm or less x0.5 mm or more and 5 mm or less x0.1 mm or more and 1 mm or less.

  In the present invention, it goes without saying that the configuration of the light source device is not limited to the configuration described above.

Next, the antenna 2 will be described.
FIG. 1 is a cross-sectional view of an antenna 2 according to the first embodiment. The antenna 2 includes an n-type semiconductor layer (first impurity-containing semiconductor layer) 22, an i-type semiconductor layer (semiconductor layer) 26 that generates terahertz waves, and a p-type semiconductor layer formed on the high-resistance substrate 24. (Second impurity-containing semiconductor layer) 23, an electrode 28 (first electrode) and an electrode (second electrode) 29 constituting a pair of electrodes.

The high-resistance substrate 24 is not particularly limited as long as it has high insulating properties, and examples thereof include a high-resistance i-type III-V compound semiconductor substrate, GaAs, InP, InAs, and InSb. Further, a Si substrate may be used.
The carrier concentration of the high resistance substrate 24, is preferably 1 × 10 ¹⁸ / cm ³ or less, more preferably 1 × 10 ¹² / cm ³ or more 1 × 10 ¹⁸ / cm ³ or less, 1 × 10 More preferably, it is ¹² / cm ³ or more and 1 × 10 ¹⁶ / cm ³ or less.

  As shown in FIG. 2, the i-type semiconductor layer 26 has a quadrangular shape when viewed from the direction in which the light pulse is incident (in plan view). Note that the shape of the i-type semiconductor layer 26 is not limited to a quadrangle, and other examples include a circle, an ellipse, and other polygons such as a triangle, a pentagon, and a hexagon. Hereinafter, “when viewed from the direction in which the light pulse is incident” is also referred to as “plan view”.

The i-type semiconductor layer 26 is made of a semiconductor material. The semiconductor material constituting the i-type semiconductor layer 26 is preferably an intrinsic semiconductor, but may contain a small amount of n-type impurities or n-type impurities. Specifically, the carrier concentration of the i-type semiconductor layer 26, 1 × preferably 10 ¹⁸ / cm ³ or less, more not more 1 × 10 ¹² / cm ³ or more 1 × 10 ¹⁸ / cm ³ or less Preferably, it is 1 × 10 ¹² / cm ³ or more and 1 × 10 ¹⁶ / cm ³ or less.

  Further, the n-type semiconductor layer 22 and the p-type semiconductor layer 23 are arranged via a predetermined gap (gap) 25 in a plan view, and the i-type semiconductor layer 26 includes the n-type semiconductor layer 22 and the p-type semiconductor. It is formed so as to straddle the gap 25 between the layer 23. Thereby, in plan view, at least a part of the i-type semiconductor layer 26 is arranged in the gap 25 between the n-type semiconductor layer 22 and the p-type semiconductor layer 23, and the n-type semiconductor layer 22 and the p-type semiconductor layer 26 are arranged. The semiconductor layer 23 is connected via an i-type semiconductor layer 26.

  In the present embodiment, as shown in FIG. 1, a part of the i-type semiconductor layer 26 is disposed in the gap 25, and the gap 25 is filled with a part of the i-type semiconductor layer 26. Thereby, a terahertz wave having a higher intensity can be generated.

Furthermore, in this antenna 2, a part of the upper surface 221 of the n-type semiconductor layer 22 and a part of the upper surface 231 of the p-type semiconductor layer 23 are connected to a part of the lower surface 262 of the i-type semiconductor layer 26. . That is, it can be said that the upper surface of the end portion in contact with the gap 25 of the p-type semiconductor layer 23 and the upper surface of the end portion in contact with the gap 25 of the n-type semiconductor layer 22 are covered with the i-type semiconductor layer 26.
In other words, the i-type semiconductor layer 26 is provided on the n-type semiconductor layer 22 and the p-type semiconductor layer 23.

  As described above, since the i-type semiconductor layer 26 is formed on the n-type semiconductor layer 22 and the p-type semiconductor layer 23, the upper surface 261 of the i-type semiconductor layer 26 includes the n-type semiconductor layer 22 and the p-type semiconductor layer 26. It is not in contact with the type semiconductor layer 23. More specifically, one side surface 227 of the n-type semiconductor layer 22 and one side surface 237 of the p-type semiconductor layer 23 face each other with the i-type semiconductor layer 26 interposed therebetween.

  With such a configuration, as shown in FIG. 1, when a voltage is applied between the n-type semiconductor layer 22 and the p-type semiconductor layer 23, the electric field 263 between the gaps 25 becomes a film of the i-type semiconductor layer 26. Formed in the interior 264. As described above, since no voltage is applied to the upper surface 261 of the i-type semiconductor layer 26 having many defects such as surface states, the leakage current can be reduced, the withstand voltage can be improved, and a terahertz wave with higher intensity can be generated.

The n-type semiconductor layer 22 is made of a semiconductor material containing n-type (first conductivity type) impurities. The carrier concentration (impurity concentration) of the n-type semiconductor layer 22 is preferably 1 × 10 ¹⁷ / cm ³ or more, more preferably 1 × 10 ²⁰ / cm ³ or more, and 1 × 10 ²⁰ / cm ^3. More preferably, it is 1 × 10 ²² / cm ³ or less. In addition, it does not specifically limit as an n-type impurity, For example, Si, Ge, S, Se etc. are mentioned.

The p-type semiconductor layer 23 is made of a semiconductor material containing p-type (second conductivity type) impurities. The carrier concentration of the p-type semiconductor layer 23 is preferably 1 × 10 ¹⁷ / cm ³ or more, more preferably 1 × 10 ²⁰ / cm ³ or more, and 1 × 10 ²⁰ / cm ³ or more to 1 × 10. More preferably, it is ²² / cm ³ or less. In addition, it does not specifically limit as a p-type impurity, For example, Zn, Mg, C etc. are mentioned.

  The n-type semiconductor layer 22 and the p-type semiconductor layer 23 are formed, for example, by forming a semiconductor layer that is not doped with impurities and doping the n-type or p-type impurities with an ion implantation method or a diffusion method. Can be formed. On the other hand, there is a method of forming the n-type semiconductor layer 22 and the p-type semiconductor layer 23 by a selective epitaxial method.

  The semiconductor material of the n-type semiconductor layer 22, the p-type semiconductor layer 23, and the i-type semiconductor layer 26 is not particularly limited, and various materials can be used. However, the higher the mobility, the higher the intensity of terahertz radiation. Therefore, a III-V group compound semiconductor is preferable. The III-V group compound semiconductor is not particularly limited, and examples thereof include GaAs, InP, InAs, InSb, and the like.

With such a pin structure including the n-type semiconductor layer 22, the i-type semiconductor layer 26, and the p-type semiconductor layer 23, the withstand voltage can be improved and a larger electric field can be formed on the pin structure. Intense terahertz waves can be generated.
Further, since the positional relationship between the n-type semiconductor layer 22 and the p-type semiconductor layer 23 is constant regardless of the thickness of the i-type semiconductor layer 26, the direction of the electric field can be made constant. Thus, the emission direction of the terahertz wave can be made constant.

The shapes of the n-type semiconductor layer 22 and the p-type semiconductor layer 23 are not particularly limited.
In this embodiment, an example is shown in FIG. The n-type semiconductor layer 22 is provided in a strip-shaped portion 224 having a strip shape, a projecting portion 223 provided in the middle of the strip-shaped portion 224, that is, in an intermediate portion, and projecting toward the p-type semiconductor layer 23, and both ends of the strip-shaped portion 224 And a pad portion 225. In the illustrated configuration, the shape of the protruding portion 223 is a quadrangle in plan view. In addition, the shape of the protrusion part 223 is not limited to a quadrangle, For example, other polygons, such as a circle, an ellipse, a triangle, a pentagon, a hexagon, etc. are mentioned.

  In the present embodiment, the p-type semiconductor layer 23 has a shape obtained by inverting the n-type semiconductor layer 22. That is, the p-type semiconductor layer 23 includes a strip-shaped portion 234 having a strip shape, a protrusion 233 that is provided in the middle of the strip-shaped portion 234, that is, in the middle portion, and protrudes toward the n-type semiconductor layer 22, and both end portions of the strip-shaped portion 234 And a pad portion 235 provided on the surface. In the illustrated configuration, the shape of the protruding portion 233 is a quadrangle in plan view. In addition, the shape of the protrusion part 233 is not limited to a quadrangle, For example, other polygons, such as circular, an ellipse, a triangle, a pentagon, a hexagon, etc. are mentioned.

  The n-type semiconductor layer 22 and the p-type semiconductor layer 23 are arranged so that the strip-shaped portion 224 of the n-type semiconductor layer 22 and the strip-shaped portion 234 of the p-type semiconductor layer 23 are parallel to each other.

  Further, as shown in FIG. 1, the thickness d1 of the n-type semiconductor layer 22 and the thickness d2 of the p-type semiconductor layer 23 are not particularly limited, and are appropriately set according to various conditions. It is preferably 10 nm or more and 1 μm or less. The thickness d1 of the n-type semiconductor layer 22 and the thickness d2 of the p-type semiconductor layer 23 may be the same or different, but are set to be the same in this embodiment.

  Further, the distance (gap distance) d of the gap 25 between the n-type semiconductor layer 22 and the p-type semiconductor layer 23 is not particularly limited and is appropriately set according to various conditions. It is preferably 10 μm or less.

  Further, the width W1 of the protruding portion 223 of the n-type semiconductor layer 22 and the width W2 of the protruding portion 233 of the p-type semiconductor layer 23 are not particularly limited and are appropriately set according to various conditions. It is preferably 10 μm or less. Note that the width W1 of the protrusion 223 of the n-type semiconductor layer 22 and the width W2 of the protrusion 233 of the p-type semiconductor layer 23 may be the same or different, but in the present embodiment, they are the same. Is set.

The electrode 28 is provided on the n-type semiconductor layer 22. That is, the electrode 28 is in contact with the n-type semiconductor layer 22 so as to cover the pad portion 225 of the n-type semiconductor layer 22 and is electrically connected to the n-type semiconductor layer 22.
The electrode 29 is provided on the p-type semiconductor layer 23. That is, the electrode 29 is in contact with the p-type semiconductor layer 23 so as to cover the pad portion 235 of the p-type semiconductor layer 23 and is electrically connected to the p-type semiconductor layer 23.

The shape of the n-type semiconductor layer 22 and the p-type semiconductor layer 23 may be the shape shown in FIG. 3 as well as the shape shown in FIG.
In FIG. 3A, the protruding portion 223 of the n-type semiconductor layer 22 is provided at one end portion of the strip-shaped portion 224, and the pad portion 225 is provided at the other end portion of the strip-shaped portion 224. Further, the protruding portion 233 of the p-type semiconductor layer 23 is provided at one end portion of the strip-shaped portion 234, and the pad portion 235 is provided at the other end portion of the strip-shaped portion 234. With this structure, the belt-like portion 224 and the belt-like portion 234 can be shortened, so that the leakage current can be reduced, the withstand voltage can be improved, and a terahertz wave with higher intensity can be generated.

  In FIG. 3B, the band-shaped portion 224 and the band-shaped portion 234 are eliminated, and the n-type semiconductor layer 22 includes a protruding portion 223 and a pad portion 225, and the p-type semiconductor layer 23 includes a protruding portion 233 and a pad. The portion 235 is formed into a shape. According to this shape, compared with the shape shown in FIG. 3A, the leakage current can be further reduced, the withstand voltage can be improved, and a terahertz wave having a higher intensity can be generated.

  In FIG. 1 to FIG. 3, the power supply device 18 is electrically connected to the electrode 28 and the electrode 29 via pads, conductors, connectors, etc. (not shown), and between the electrode 28 and the electrode 29, A DC voltage is applied so that the electrode 28 side is positive.

Next, an example of a method for manufacturing the antenna 2 of the terahertz wave generator 1 will be described.
First, as shown in FIG. 7A, an insulating film 71 is formed on the upper surface of the high resistance substrate 24, and a resist layer 81 is further formed on the upper surface of the insulating film 71. After removing the resist layer 81 where the p-type semiconductor layer 23 is to be formed on the upper surface of the high-resistance substrate 24, the insulating film 71 is selectively removed by etching using the resist layer 81 as a mask.
In the present embodiment, a case where a high-resistance GaAs substrate is used as the high-resistance substrate 24 will be described. As the insulating film 71, a SiO ₂ film or a SiN film can be used.

Next, as shown in FIG. 7B, after removing the resist layer 81, the p-type semiconductor layer 23 containing a p-type impurity is formed by epitaxial growth on the high-resistance substrate 24 that is selectively opened and exposed. Selectively form. Examples of the epitaxial growth method include a vapor phase epitaxial growth method, a metal organic vapor phase growth method, and a molecular beam epitaxial growth method.
Alternatively, after the i-type semiconductor is selectively epitaxially grown, a p-type impurity may be doped into the i-type semiconductor by, for example, an ion implantation method or a diffusion method. Thereby, the p-type semiconductor layer 23 is formed.

  Next, as shown in FIG. 7C, a resist layer 82 is formed on the upper surfaces of the p-type semiconductor layer 23 and the insulating film 71, and a resist at a site where the n-type semiconductor layer 22 is formed on the upper surface of the insulating film 71. After the layer 82 is removed, the insulating film 71 is selectively removed by etching using the resist layer 82 as a mask.

Next, as shown in FIG. 7D, after removing the resist layer 82, the n-type semiconductor layer 22 containing an n-type impurity is formed on the high-resistance substrate 24 selectively opened and exposed by an epitaxial growth method. Selectively form. Examples of the epitaxial growth method include a vapor phase epitaxial growth method, a metal organic vapor phase growth method, and a molecular beam epitaxial growth method.
Alternatively, after selectively epitaxially growing an i-type semiconductor, an n-type impurity may be doped into the i-type semiconductor by, for example, an ion implantation method or a diffusion method. Thereby, the n-type semiconductor layer 22 is formed.

  Next, as illustrated in FIG. 8A, an i-type semiconductor layer 26 is formed on the upper surfaces of the high-resistance substrate 24, the p-type semiconductor layer 23, and the n-type semiconductor layer 22. As a formation method, an epitaxial growth method or the like is used. Next, a resist layer is formed, the resist layer other than the part where the i-type semiconductor layer 26 is formed is removed, and the resist layer is left on the upper surface of the i-type semiconductor layer 26.

Next, as shown in FIG. 8B, the i-type semiconductor layer 26 is etched using the resist layer on the upper surface of the i-type semiconductor layer 26 as a mask, and straddles the p-type semiconductor layer 23 and the n-type semiconductor layer 22. The i-type semiconductor layer 26 is formed to have such a shape.
As a result, the i-type semiconductor layer 26 is formed so as to fill the gap 25 between the p-type semiconductor layer 23 and the n-type semiconductor layer 22, and a part of the lower surface 262 of the i-type semiconductor layer 26 and p A part of the upper surface 231 of the n-type semiconductor layer 23 and a part of the upper surface 221 of the n-type semiconductor layer 22 are connected, and the upper surface 261 of the i-type semiconductor layer 26 is connected to the p-type semiconductor layer 23 and the n-type semiconductor layer 22. A structure that does not contact is formed.

Next, after forming a metal layer, a mask is formed with a resist layer, and the metal layer is etched to form electrodes 28 and 29 as shown in FIG. 8C.
The antenna 2 is manufactured as described above. As the electrode, any low-resistance material can be used without limitation. For example, gold, silver, copper, platinum, aluminum and titanium can be used.

Next, the operation of the terahertz wave generator 1 will be described.
In the terahertz wave generator 1, first, an optical pulse is generated by the optical pulse generator 4 of the light source device 3. The pulse width of the optical pulse generated by the optical pulse generator 4 is larger than the target pulse width. The optical pulse generated by the optical pulse generation unit 4 passes through the waveguide, and sequentially passes through the first pulse compression unit 5, the amplification unit 6, and the second pulse compression unit 7 in this order.

  First, in the first pulse compression unit 5, pulse compression based on saturable absorption is performed on the optical pulse, and the pulse width of the optical pulse is reduced. Next, the optical pulse is amplified by the amplification unit 6. Finally, in the second pulse compression unit 7, pulse compression based on group velocity dispersion compensation is performed on the optical pulse, and the pulse width of the optical pulse is further reduced. In this way, an optical pulse having a target pulse width is generated and emitted from the second pulse compression unit 7.

The power supply device 18 is connected to the electrode 28 and the electrode 29 of the antenna 2, a positive potential is applied to the p-type semiconductor layer 23, and a negative potential is applied to the n-type semiconductor layer 22.
The light pulse emitted from the light source device 3 is applied to the i-type semiconductor layer 26 in the gap 25 of the antenna 2, and a terahertz wave is generated in the i-type semiconductor layer 26. The terahertz wave is emitted from the lower surface 262 of the i-type semiconductor layer 26, that is, the emission surface.

  As described above, according to the terahertz wave generator 1, the withstand voltage is improved by the pin structure, and a larger electric field can be formed on the pin structure, thereby generating a high-intensity terahertz wave. it can.

  In the antenna 2 of the present embodiment, as shown in FIG. 1, the i-type semiconductor layer 26 is in contact with the p-type semiconductor layer 23 and the n-type semiconductor layer 22 by the lower surface 262 of the i-type semiconductor layer 26. An electric field 263 of the gap 25 can be formed in the film interior 264 of the i-type semiconductor layer 26. With such a structure, a leak current that conducts the upper surface 261 of the i-type semiconductor layer 26 in which many defects such as surface states exist is not generated. Accordingly, the withstand voltage is improved, and a larger electric field can be formed on the withstand voltage, whereby a high-intensity terahertz wave can be generated.

  Further, since the positional relationship between the n-type semiconductor layer 22 and the p-type semiconductor layer 23 is constant regardless of the thickness of the i-type semiconductor layer 26, the direction of the electric field can be made constant. Thus, the emission direction of the terahertz wave can be made constant.

  Further, since the light source device 3 includes the first pulse compression unit 5, the amplification unit 6, and the second pulse compression unit 7, the light source device 3 can be downsized, and the terahertz wave generator 1 can be downsized. As shown, an optical pulse having a desired wave height and a desired pulse width can be generated, whereby a desired terahertz wave can be reliably generated.

  In this embodiment, the i-type semiconductor layer 26 has a shape that largely covers the protruding portion 233 of the p-type semiconductor layer 23 and the protruding portion 223 of the n-type semiconductor layer 22 in plan view. The shape is not limited. For example, the i-type semiconductor layer 26 may be formed so as to cover at least the gap 25 between the protruding portion 233 of the p-type semiconductor layer 23 and the protruding portion 223 of the n-type semiconductor layer 22.

Second Embodiment
FIG. 9 is a cross-sectional view showing a second embodiment of the antenna of the present invention.
Hereinafter, the second embodiment will be described with a focus on the differences from the first embodiment described above, and the description of the same matters will be omitted.

  As shown in FIG. 9, in the antenna 2 of the second embodiment, at least a region of the gap 25 between the protrusion 233 of the p-type semiconductor layer 23 and the protrusion 223 of the n-type semiconductor layer 22 of the high resistance substrate 24. A groove 265 of the high resistance substrate is formed, the i-type semiconductor layer 26 fills the groove 265 of the high resistance substrate, and the lower surface 262 of the i-type semiconductor layer 26 is in contact with the bottom surface of the groove 265 in the region of the gap 25. Yes. Further, one side surface 227 of the n-type semiconductor layer 22 and one side surface 237 of the p-type semiconductor layer 23 are opposed to each other with the i-type semiconductor layer 26 interposed therebetween.

  Accordingly, an electric field 263 applied between the protrusion 233 of the p-type semiconductor layer 23 and the protrusion 223 of the n-type semiconductor layer 22 is further increased from the lower surface 262 of the i-type semiconductor layer 26 having many defect levels. It is further away and is located inside the i-type semiconductor layer 26 more. Accordingly, it is possible to more reliably prevent the occurrence of a leakage current in the gap 25 between the n-type semiconductor layer 22 and the p-type semiconductor layer 23.

  Next, regarding the method for manufacturing the antenna 2 of the terahertz wave generating device 1, the difference from the first embodiment is only the portion where the groove 265 of the high resistance substrate is formed. A process example will be described.

  First, as shown in FIG. 11A, the first process example is a method of forming the groove 265 of the high resistance substrate 24 at the beginning of the process. A resist layer 83 for masking is formed at a position where the p-type semiconductor layer 23 and the n-type semiconductor layer 22 are to be formed on the high-resistance substrate 24, and the high-resistance substrate 24 is etched using the resist layer 83 as a mask. Thus, the groove 265 is formed. After removing the resist layer 83, the process continues to FIG. The p-type semiconductor layer 23 and the n-type semiconductor layer 22 are formed at the position where the resist layer 83 is removed in the subsequent steps. The subsequent description is omitted.

In the second process example, the processes from FIG. 7A to FIG. 7D are the same as those in the first embodiment. In the second process example of the second embodiment, after removing the insulating film 71 in FIG. 7D, a groove 265 of the high resistance substrate is formed as shown in FIG. 11B.
The groove may be formed by etching using the p-type semiconductor layer 23 and the n-type semiconductor layer 22 as a mask, or a resist layer is formed on the p-type semiconductor layer 23 and the n-type semiconductor layer 22 as a mask. Then, etching may be formed using the resist layer as a mask. Thereafter, the process continues to the step of FIG.
According to this antenna 2, the same effect as the first embodiment described above can be obtained.
This second embodiment can also be applied to a third embodiment described later.

<Third Embodiment>
FIG. 10 is a cross-sectional view showing a third embodiment of the antenna of the present invention.
Hereinafter, the third embodiment will be described with a focus on differences from the first embodiment described above, and descriptions of the same matters will be omitted.

  As shown in FIG. 10, in the antenna 2 of the third embodiment, the n-type semiconductor layer 22 has an impurity concentration distribution in the film thickness direction, and the n-type semiconductor layer is on the lower surface 222 side of the n-type semiconductor layer 22. The low concentration region 226a is provided, and the n type semiconductor layer high concentration region 226b is provided on the upper surface 221 side of the n type semiconductor layer 22.

  The impurity concentration is omitted because it has been described in the section of the first embodiment, but the impurity concentration in the high concentration region 226b may be higher than the impurity concentration in the low concentration region 226a region, but it is preferably one digit or more. Concerning the impurity concentration distribution, the high concentration region and the low concentration region may be constituted by two layers or multiple layers, or the concentration may change continuously with a concentration gradient (concentration distribution). .

Further, the p-type semiconductor layer 23 has an impurity concentration distribution in the film thickness direction, and a low-concentration region 236 a of the p-type semiconductor layer is provided on the lower surface 232 side of the p-type semiconductor layer 23. A high-concentration region 236b of a p-type semiconductor layer is provided on the upper surface 231 side.
The impurity concentration in the high-concentration region 236b may be higher than the impurity concentration in the low-concentration region 236a, but it is preferably one digit or more.

  Regarding the impurity concentration distribution, a region having a high concentration and a region having a low concentration may be constituted by two layers or multiple layers, or the concentration may continuously change with a concentration gradient. Further, one side surface 227 of the n-type semiconductor layer 22 and one side surface 237 of the p-type semiconductor layer 23 are opposed to each other with the i-type semiconductor layer 26 interposed therebetween.

  Thus, as in the second embodiment, the electric field 263 applied between the protruding portion 233 of the p-type semiconductor layer 23 and the protruding portion 223 of the n-type semiconductor layer 22 is an i-type semiconductor layer having many defect levels. It is further away from the lower surface 262 of the I-type semiconductor layer 26 and is located more inside the i-type semiconductor layer 26. Accordingly, it is possible to more reliably prevent the occurrence of a leakage current in the gap 25 between the n-type semiconductor layer 22 and the p-type semiconductor layer 23.

  Regarding the manufacturing process, the impurity addition conditions are controlled so that the p-type semiconductor layer 23 and the n-type semiconductor layer 22 are epitaxially grown, and the impurity concentration is controlled to be low at the initial stage of growth. It can produce by controlling so that it may increase. Accordingly, since the step of forming the groove 265 of the high resistance substrate 24 as in the second embodiment can be omitted, the same effect can be obtained in a shorter step.

  According to this antenna 2, the same effect as the first embodiment and the second embodiment described above can be obtained. Furthermore, there exists an effect that it can manufacture simply by a process shorter than 2nd Embodiment.

<Embodiment of Imaging Apparatus>
12 is a block diagram showing an embodiment of the imaging apparatus of the present invention, FIG. 13 is a plan view showing a terahertz wave detecting apparatus of the imaging apparatus shown in FIG. 12, and FIG. 14 is a spectrum of the target in the terahertz band. The graph shown in FIG. 15 is an image of the distribution of the substances A, B and C of the object.

  As illustrated in FIG. 12, the imaging apparatus 100 includes a terahertz wave generation apparatus 1 that generates a terahertz wave, and a terahertz wave detection apparatus that detects a terahertz wave that is emitted from the terahertz wave generation apparatus 1 and transmitted or reflected by the object 150. 11 and an image forming unit 12 that generates an image of the object 150, that is, image data, based on the detection result of the terahertz wave detection device 11. Description of the terahertz wave generator 1 is omitted.

As shown in FIG. 13, as the terahertz wave detection device 11, for example, a filter 15 that transmits a terahertz wave having a target wavelength and a terahertz wave having a target wavelength that has passed through the filter 15 are converted into heat and detected. What is provided with the detection part 17 which performs is used. For example, a detector that converts terahertz waves into heat and detects them, that is, a detector that converts terahertz waves into heat and can detect the energy (intensity) of the terahertz waves is used.
Examples of such a detection unit include a pyroelectric sensor and a bolometer. Needless to say, the terahertz wave detection device 11 is not limited to the above-described configuration.

  The filter 15 includes a plurality of pixels (unit filter units) 16 that are two-dimensionally arranged. That is, the pixels 16 are arranged in a matrix.

  Each pixel 16 has a plurality of regions that transmit terahertz waves having different wavelengths, that is, a plurality of regions that have different wavelengths of terahertz waves that pass (hereinafter also referred to as “passing wavelengths”). In the illustrated configuration, each pixel 16 includes a first region 161, a second region 162, a third region 163, and a fourth region 164.

  The detection unit 17 also includes a first unit detection provided corresponding to the first region 161, the second region 162, the third region 163, and the fourth region 164 of each pixel 16 of the filter 15. A unit 171, a second unit detector 172, a third unit detector 173, and a fourth unit detector 174. Each first unit detector 171, each second unit detector 172, each third unit detector 173, and each fourth unit detector 174 are respectively the first region 161 of each pixel 16, The terahertz wave that has passed through the second region 162, the third region 163, and the fourth region 164 is converted into heat and detected. Thereby, each of the pixels 16 can reliably detect terahertz waves having four target wavelengths.

Next, a usage example of the imaging apparatus 100 will be described.
First, as shown in FIG. 15, an object 150 to be subjected to spectral imaging is composed of three substances A, B, and C. The imaging apparatus 100 performs spectral imaging of the object 150. Here, as an example, the terahertz wave detection device 1 detects a terahertz wave reflected from the object 150.

Next, in each pixel 16 of the filter 15 of the terahertz wave detection device 1 illustrated in FIG. 13, the first region 161 and the second region 162 are used.
Further, the transmission wavelength of the first region 161 is λ1, the transmission wavelength of the second region 162 is λ2, the intensity of the component of wavelength λ1 of the terahertz wave reflected by the object 150 is α1, and the intensity of the component of wavelength λ2 is When α2 is set, the difference (α2−α1) between the intensity α2 and the intensity α1 can be distinguished from each other among the substance A, the substance B, and the substance C so that they can be distinguished from each other. The pass wavelength λ2 of the second region 162 is set.

As shown in FIG. 14, in the substance A, the difference (α2−α1) between the intensity α2 of the component of wavelength λ2 and the intensity α1 of the component of wavelength λ1 reflected by the target 150 is a positive value.
In the substance B, the difference (α2−α1) between the intensity α2 and the intensity α1 is zero.
Further, in the substance C, the difference (α2−α1) between the intensity α2 and the intensity α1 is a negative value.

  When spectral imaging of the object 150 is performed by the imaging apparatus 100, first, a terahertz wave is generated by the terahertz wave generator 1, and the object 150 is irradiated with the terahertz wave. Then, the terahertz wave reflected by the object 150 is detected by the terahertz wave detection device 11 as the intensity α1 and the intensity α2. This detection result is sent to the image forming unit 12. Note that the irradiation of the terahertz wave to the object 150 and the detection of the terahertz wave reflected by the object 150 are performed on the entire object 150.

  In the image forming unit 12, the intensity α2 of the component of the wavelength λ2 of the terahertz wave that has passed through the second region 162 of the filter 15 and the wavelength of the terahertz wave that has passed through the first region 161 based on the detection result described above. The difference (α2−α1) from the intensity α1 of the component of λ1 is obtained. Then, in the object 150, the part where the calculated difference is a positive value is determined as the substance A, the part where the calculated difference is zero is determined as the substance B, and the part where the calculated difference is a negative value is determined as the substance C. To do.

  Further, the image forming unit 12 creates image data of an image indicating the distribution of the substances A, B, and C of the object 150 as shown in FIG. The image data is sent from the image forming unit 12 to a monitor (not shown), and an image showing the distribution of the substances A, B, and C of the object 150 is displayed on the monitor. In this case, for example, the region where the substance A of the object 150 is distributed is displayed in black, the region where the substance B is distributed is gray, and the region where the substance C is distributed is displayed in white. As described above, the imaging apparatus 100 can simultaneously identify each substance constituting the object 150 and measure the distribution of each property.

  The application of the imaging apparatus 100 is not limited to the above, and for example, a terahertz wave is irradiated on a person, a terahertz wave transmitted or reflected by the person is detected, and the image forming unit 12 performs processing. Thus, it is possible to determine whether or not the person has a handgun, a knife, an illegal drug, or the like.

<Embodiment of measuring device>
FIG. 16 is a block diagram showing an embodiment of the measuring apparatus of the present invention.
Hereinafter, the embodiment of the measurement apparatus will be described with a focus on the differences from the above-described embodiment of the imaging apparatus, the same matters are denoted by the same reference numerals as those of the above-described embodiment, and the detailed description thereof will be omitted.

  As illustrated in FIG. 16, the measurement device 200 includes a terahertz wave generation device 1 that generates a terahertz wave, and a terahertz wave detection device that detects the terahertz wave that is emitted from the terahertz wave generation device 1 and transmitted or reflected by the object 160. 11 and a measurement unit 13 that measures the object 160 based on the detection result of the terahertz wave detection device 11.

Next, a usage example of the measuring device 200 will be described.
When performing spectroscopic measurement of the object 160 with the measuring device 200, first, a terahertz wave is generated by the terahertz wave generator 1, and the object 160 is irradiated with the terahertz wave. Then, the terahertz wave transmitted or reflected by the object 160 is detected by the terahertz wave detection device 11. This detection result is sent to the measurement unit 13. Note that the irradiation of the terahertz wave to the object 160 and the detection of the terahertz wave transmitted or reflected by the object 160 are performed on the entire object 160.

  In the measurement unit 13, the intensities of the terahertz waves that have passed through the first region 161, the second region 162, the third region 163, and the fourth region 164 of the filter 15 are grasped from the detection result described above. The analysis of the components of the object 160 and the distribution thereof is performed.

<Embodiment of Camera>
FIG. 17 is a block diagram showing an embodiment of the camera of the present invention.
Hereinafter, the embodiment of the camera will be described focusing on the differences from the above-described embodiment of the imaging apparatus, the same matters will be denoted by the same reference numerals as those of the above-described embodiment, and detailed description thereof will be omitted.
As illustrated in FIG. 17, the camera 300 includes a terahertz wave generation device 1 that generates a terahertz wave, and a terahertz wave detection device 11 that detects the terahertz wave that is emitted from the terahertz wave generation device 1 and transmitted or reflected by the object 170. And.

Next, a usage example of the camera 300 will be described.
When the object 170 is imaged by the camera 300, first, the terahertz wave is generated by the terahertz wave generator 1, and the object 170 is irradiated with the terahertz wave. Then, the terahertz wave transmitted or reflected by the object 170 is detected by the terahertz wave detection device 11. This detection result is sent to and stored in the storage unit 14. The irradiation of the terahertz wave to the object 170 and the detection of the terahertz wave transmitted or reflected by the object 170 are performed on the entire object 170.
Moreover, the detection result mentioned above can also be transmitted to external apparatuses, such as a personal computer, for example. In the personal computer, each process can be performed based on the detection result.

  As described above, the antenna, the terahertz wave generation device, the camera, the imaging device, and the measurement device of the present invention have been described based on the illustrated embodiment, but the present invention is not limited thereto, and the configuration of each unit is as follows. Any structure having a similar function can be substituted. In addition, any other component may be added to the present invention.

  In addition, the present invention may be a combination of any two or more configurations (features) of the embodiments.

  In the above embodiment, the first impurity-containing semiconductor layer is an n-type semiconductor layer and the second impurity-containing semiconductor layer is a p-type semiconductor layer. However, the present invention is not limited to this, and the first impurity-containing semiconductor layer is used. The layer may be a p-type semiconductor layer, and the second impurity-containing semiconductor layer may be an n-type semiconductor layer.

  In the present invention, in the light source device, the light pulse generator may be a separate body.

  If the high-performance antenna, terahertz wave generator, camera, imaging device, and measuring device realized in the present invention are used, it can be applied to a highly sensitive analyzer, for example, used for an inspection device for quality inspection in pharmaceutical manufacture. it can. In addition, because of the terahertz wave characteristic that the molecular bonding state can be detected with high sensitivity, it can be used for analysis of polymer substances, for example, high-sensitivity imaging devices such as proteins and analytical measurement devices. Therefore, it is expected to be applied to the medical field and greatly contributes to its development.

  DESCRIPTION OF SYMBOLS 1 ... Terahertz wave generator 2 ... Antenna 3 ... Light source device 4 ... Optical pulse generator 5 ... 1st pulse compression part 6 ... Amplification part 7 ... 2nd pulse compression part 11 ... Terahertz wave detection apparatus 12 ... Image formation part DESCRIPTION OF SYMBOLS 13 ... Measurement part 14 ... Memory | storage part 15 ... Filter 16 ... Pixel 17 ... Detection part 18 ... Power supply device 20 ... Antenna main body 22 ... N-type semiconductor layer 23 ... P-type semiconductor layer 24 ... High resistance substrate 25 ... Gap 26 ... i-type Semiconductor layer 28, 29 ... Electrode 30 ... Diffraction grating 31 ... Substrate 32, 35 ... Cladding layer 33 ... Active layer 34 ... Etching stop layer for waveguide construction process 36 ... Contact layer 37 ... Insulating layer 38, 391-395 ... Electrode 81 , 82, 83, 85 ... resist layer 84 ... metal layer 100 ... imaging device 150, 160, 170 ... object 161 ... 1 area 162 ... 2nd area 163 ... 3rd area 164 ... 4th area 171 ... 1st unit detection part 172 ... 2nd unit detection part 173 ... 3rd unit detection part 174 ... 4th Unit detection unit 200 ... Measuring device 221 ... Upper surface of n-type semiconductor layer 222 ... Lower surface of n-type semiconductor layer 223 ... Projection part of n-type semiconductor layer 224 ... Band-like part of n-type semiconductor layer 225 ... Pad part 226a ... n-type semiconductor Low-concentration region 226b High concentration region of n-type semiconductor layer 227 One side surface of n-type semiconductor layer 231 Upper surface of p-type semiconductor layer 232 Lower surface of p-type semiconductor layer 233 Projecting portion of p-type semiconductor layer 234... P-type semiconductor layer strip 235... Pad portion 236 a... P-type semiconductor layer low-concentration region 236 b... P-type semiconductor layer high-concentration region 237. Upper surface of semiconductor layer 262 ... Lower surface of i-type semiconductor layer 263 ... Electric field in gap 264 ... Inside film of i-type semiconductor layer 265 ... Groove in high-resistance substrate 300 ... Camera.

Claims (13)

An antenna that generates terahertz waves when irradiated with pulsed light,
A substrate,
A first impurity-containing semiconductor layer located on the substrate and made of a semiconductor material containing an impurity of a first conductivity type;
A second impurity-containing semiconductor layer made of a semiconductor material located on the substrate and containing an impurity of a second conductivity type different from the first conductivity type;
An i-type semiconductor layer formed on an i-type semiconductor material that is located on the substrate and does not contain impurities of a first conductivity type and a second conductivity type;
A first electrode electrically connected to the first impurity-containing semiconductor layer;
A second electrode electrically connected to the second impurity-containing semiconductor layer,
In plan view, the first impurity-containing semiconductor layer and the second impurity-containing semiconductor layer are arranged with a predetermined gap therebetween,
The i-type semiconductor layer is provided to fill the gap between the first impurity-containing semiconductor layer and the second impurity-containing semiconductor layer ,
The i-type semiconductor layer is disposed on a side of the first impurity-containing semiconductor layer irradiated with the pulse wave and on a side of the second impurity-containing semiconductor layer irradiated with the pulse wave. antenna.   The i-type semiconductor layer covers an end portion of the first impurity-containing semiconductor layer in contact with the gap and an end portion of the second impurity-containing semiconductor layer in contact with the gap. The described antenna. The substrate has a groove in a portion corresponding to the gap,
The antenna according to claim 1, wherein the i-type semiconductor layer is provided so as to fill the groove.   The first impurity-containing semiconductor layer is provided with a concentration distribution so that the first impurity concentration increases from a lower surface in contact with the substrate toward an upper surface. The antenna according to item.   5. The concentration distribution of the second impurity-containing semiconductor layer is provided such that the second impurity concentration increases from a lower surface in contact with the substrate toward an upper surface. The antenna according to item. The first electrode is provided on the first impurity-containing semiconductor layer,
The antenna according to any one of claims 1 to 5, wherein a part of the first electrode is in contact with a part of the first impurity-containing semiconductor layer. The second electrode is provided on the second impurity-containing semiconductor layer,
The antenna according to any one of claims 1 to 6, wherein a part of the second electrode is in contact with a part of the second impurity-containing semiconductor layer.   The antenna according to claim 1, further comprising an insulating layer located between the i-type semiconductor layer and the substrate at a position of at least a part of the gap. .   The antenna according to any one of claims 1 to 8, wherein the i-type semiconductor material is a III-V compound semiconductor. A light source that generates pulsed light;
An antenna that generates terahertz waves by being irradiated with pulsed light generated by the light source,
The antenna is
A substrate,
A first impurity-containing semiconductor layer located on the substrate and made of a semiconductor material containing an impurity of a first conductivity type;
A second impurity-containing semiconductor layer made of a semiconductor material located on the substrate and containing an impurity of a second conductivity type different from the first conductivity type;
An i-type semiconductor layer formed on an i-type semiconductor material that is located on the substrate and does not contain impurities of the first conductivity type and the second conductivity type;
A first electrode electrically connected to the first impurity-containing semiconductor layer;
A second electrode electrically connected to the second impurity-containing semiconductor layer,
In plan view, the first impurity-containing semiconductor layer and the second impurity-containing semiconductor layer are arranged with a predetermined gap therebetween,
The i-type semiconductor layer is provided to fill the gap between the first impurity-containing semiconductor layer and the second impurity-containing semiconductor layer ,
The i-type semiconductor layer is disposed on a side of the first impurity-containing semiconductor layer irradiated with the pulse wave and on a side of the second impurity-containing semiconductor layer irradiated with the pulse wave. Terahertz wave generator. A terahertz wave generator for generating terahertz waves;
A terahertz wave detection device that detects a terahertz wave that is emitted from the terahertz wave generation device and is transmitted or reflected by an object, and
The terahertz wave generator includes a light source that generates pulsed light,
An antenna that generates terahertz waves by being irradiated with pulsed light generated by the light source,
The antenna is
A substrate,
A first impurity-containing semiconductor layer located on the substrate and made of a semiconductor material containing an impurity of a first conductivity type;
A second impurity-containing semiconductor layer made of a semiconductor material located on the substrate and containing an impurity of a second conductivity type different from the first conductivity type;
An i-type semiconductor layer formed on an i-type semiconductor material that is located on the substrate and does not contain impurities of the first conductivity type and the second conductivity type;
A first electrode electrically connected to the first impurity-containing semiconductor layer;
A second electrode electrically connected to the second impurity-containing semiconductor layer,
In plan view, the first impurity-containing semiconductor layer and the second impurity-containing semiconductor layer are arranged with a predetermined gap therebetween,
The i-type semiconductor layer is provided to fill the gap between the first impurity-containing semiconductor layer and the second impurity-containing semiconductor layer ,
The i-type semiconductor layer is disposed on a side of the first impurity-containing semiconductor layer irradiated with the pulse wave and on a side of the second impurity-containing semiconductor layer irradiated with the pulse wave. camera. A terahertz wave generator for generating terahertz waves;
A terahertz wave detection device that detects a terahertz wave that is emitted from the terahertz wave generation device and is transmitted or reflected by an object;
An image forming unit that generates an image of the object based on a detection result of the terahertz wave detection device;
The terahertz wave generator includes a light source that generates pulsed light,
An antenna that generates terahertz waves by being irradiated with pulsed light generated by the light source,
The antenna is
A substrate,
A first impurity-containing semiconductor layer located on the substrate and made of a semiconductor material containing an impurity of a first conductivity type;
A second impurity-containing semiconductor layer made of a semiconductor material located on the substrate and containing an impurity of a second conductivity type different from the first conductivity type;
An i-type semiconductor layer formed on an i-type semiconductor material that is located on the substrate and does not contain impurities of the first conductivity type and the second conductivity type;
A first electrode electrically connected to the first impurity-containing semiconductor layer;
A second electrode electrically connected to the second impurity-containing semiconductor layer,
In plan view, the first impurity-containing semiconductor layer and the second impurity-containing semiconductor layer are arranged with a predetermined gap therebetween,
The i-type semiconductor layer is provided to fill the gap between the first impurity-containing semiconductor layer and the second impurity-containing semiconductor layer ,
The i-type semiconductor layer is disposed on a side of the first impurity-containing semiconductor layer irradiated with the pulse wave and on a side of the second impurity-containing semiconductor layer irradiated with the pulse wave. Imaging device. A terahertz wave generator for generating terahertz waves;
A terahertz wave detection device that detects a terahertz wave that is emitted from the terahertz wave generation device and is transmitted or reflected by an object;
Based on the detection result of the terahertz wave detection device, comprising a measurement unit that measures the object,
The terahertz wave generator includes a light source that generates pulsed light,
An antenna that generates terahertz waves by being irradiated with pulsed light generated by the light source,
The antenna is
A substrate,
A first impurity-containing semiconductor layer located on the substrate and made of a semiconductor material containing an impurity of a first conductivity type;
A second impurity-containing semiconductor layer made of a semiconductor material located on the substrate and containing an impurity of a second conductivity type different from the first conductivity type;
An i-type semiconductor layer formed on an i-type semiconductor material that is located on the substrate and does not contain impurities of the first conductivity type and the second conductivity type;
A first electrode electrically connected to the first impurity-containing semiconductor layer;
A second electrode electrically connected to the second impurity-containing semiconductor layer,
In plan view, the first impurity-containing semiconductor layer and the second impurity-containing semiconductor layer are arranged with a predetermined gap therebetween,
The i-type semiconductor layer is provided to fill the gap between the first impurity-containing semiconductor layer and the second impurity-containing semiconductor layer ,
The i-type semiconductor layer is disposed on a side of the first impurity-containing semiconductor layer irradiated with the pulse wave and on a side of the second impurity-containing semiconductor layer irradiated with the pulse wave. Measuring device.

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