JP2018189523A - Device for measurement, and measurement sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for measurement, allowing stable measurement to be performed and downsizing to be easily achieved.SOLUTION: A device 100A for measurement of the present invention includes a semiconductor substrate 5 through which light L having a specified wavelength can transmit, a metal layer 10 laminated on the surface 5b of the semiconductor substrate 5, which constitutes a Schottky barrier at an interface 8 with the semiconductor substrate 5, having an antenna part 15 which causes surface plasmon resonance S when exposed to the light L, and a reaction layer 20 formed on the surface 10b of the metal layer 10, being reactive to a specific detection substance (antigen P).SELECTED DRAWING: Figure 2

Description

  The present invention relates to a measurement device and a measurement sensor.

  Surface plasmon resonance (SPR) is known as a phenomenon in which an evanescent wave generated by totally reflecting light at an interface of a dielectric metal is coupled to resonance vibration of free electrons on the surface of the metal. The resonance condition of SPR depends on the incident angle and wavelength of light, the dielectric constant of the metal, the dielectric constant of the dielectric in contact with the metal, etc., and particularly changes sensitively due to the change of the dielectric constant of the dielectric. Therefore, the SPR can capture the density of the chemical substance on the surface of the metal film as a change in the dielectric, and is used for a chemical measurement or a biological measurement, a sensor used in the measurement, or the like.

For example, Patent Document 1 discloses the following configuration;
(1) Conductor film having a first main surface and a second main surface (2) An excitation light incident surface, a reflection surface, and an exit surface, and the excitation light incident on the incident surface is reflected by the reflection surface The incident surface, the reflecting surface, and the emitting surface are arranged so as to be emitted from the emitting surface as reflected light, and has a dielectric medium (3) bonding surface in which the reflecting surface is in close contact with the first main surface. An exposed channel is formed, and a bonding surface is provided inside the channel forming body (4) bonded to the second main surface, and is fixed to the second main surface, and the reactant reacts. Reaction field providing material for providing a reaction field (5) Irradiation mechanism for irradiating a dielectric medium with excitation light and causing the excitation light to enter the reflection surface at a resonance angle (6) Light quantity of surface plasmon excitation fluorescence emitted from the reaction field A first light amount sensor (7) that measures the amount of reflected light; a second light amount sensor (8) that measures the amount of reflected light; Get the measurement results of the quantity of light, the measuring device including a bubble detector for detecting the mixing of air bubbles into the flow path is disclosed when the quantity of reflected light increases beyond a reference.

Japanese Patent Laying-Open No. 2015-99166

As disclosed in Patent Document 1 described above, the measurement apparatus that performs desired measurement by measuring the amount of reaction light has the following configuration;
[1] A prism having a predetermined size for arranging the incident surface and the reflecting surface so as to satisfy the total reflection condition. [2] In order to detect the angle change and the light amount of the reflected light, the rotating optical system (that is, And an optical system capable of receiving light while changing the angle of the light receiver around the light reflection position) and a rotating optical system operation technique for performing stable measurement. Therefore, the conventional measuring apparatus based on SPR has a problem that stable measurement can be performed and it is difficult to reduce the size.

The present inventor selects a semiconductor as a base material, forms a metal film on the surface of the semiconductor substrate, and enters near infrared light from a surface opposite to the metal film in the semiconductor substrate (hereinafter referred to as a back surface). We focused on the fact that no prism is needed. In addition, as described below, the present inventor
-A metal film is formed on the surface of the semiconductor substrate, and free electrons in the metal film are excited by SPR to generate a surface current along the surface of the semiconductor substrate-The surface of the metal film and the back surface of the semiconductor substrate By finding out the surface current to the electrodes connected between them, a rotating optical system is no longer required, and the components of the measuring device can be easily made into one chip, and the present invention has been completed. It was.

  The present invention has been made in consideration of the above-described circumstances, and provides a measurement device and a measurement sensor that enable stable measurement and can be easily reduced in size.

  A measuring device according to the present invention is laminated on a surface of a semiconductor substrate capable of transmitting light of a predetermined wavelength, and forms a Schottky barrier at the interface with the semiconductor substrate. A metal layer having an antenna part that causes surface plasmon resonance when irradiated with light, a reaction layer formed on the surface of the antenna part and configured to be able to react with a specific detection substance, and a surface of the semiconductor substrate Comprises an opposite surface and an electrode portion electrically connected to the metal layer.

  According to the measurement device described above, when the metal layer is irradiated with light of a predetermined wavelength from the semiconductor substrate side and a reaction with a specific detection substance occurs in the reaction layer, the metal is determined according to this reaction and SPR. Since the surface current in the layer changes, the presence or absence of a specific detection substance and the amount of the detection substance in the reaction layer can be easily measured by confirming the current value taken out to the electrode part. In the configuration of the measurement device described above, the semiconductor substrate and the metal layer can be stacked on one chip, so that the relative arrangement of these configurations is easily fixed. In addition, since the metal layer is irradiated with light of a specific wavelength from the semiconductor substrate side, light having a relatively long wavelength (that is, light having a wavelength longer than visible light) such as infrared light can be used. Since the interference between the light of the wavelength and the reaction layer, the specific detection substance, and the sample can be suppressed, more stable measurement can be performed. In addition, since each of the above-described components can be stacked and mounted on a single chip, a large-sized device such as a rotating optical system is not required, and the measurement device can be easily downsized.

  A measurement sensor according to the present invention includes a light source that emits light of a predetermined wavelength, a semiconductor substrate that is stacked on the light source and is capable of transmitting light of the predetermined wavelength, and the light source in the semiconductor substrate opposite to the light source. A metal layer that is laminated on the surface, forms a Schottky barrier at the interface with the semiconductor substrate, and has an antenna part that causes surface plasmon resonance when irradiated with light of the predetermined wavelength, and a surface of the antenna part A reaction layer formed and configured to be capable of reacting with a specific detection substance; a surface opposite to the surface of the semiconductor substrate; and an electrode portion electrically connected to the metal layer. Features.

  According to the above-mentioned measurement sensor, the same operation effect as the above-mentioned measurement device can be obtained. Further, according to the above-described measurement sensor, the light source is laminated on the surface (back surface) opposite to the metal layer in the semiconductor substrate, and the electrode portion for connecting the metal layer and the back surface side of the semiconductor substrate is provided. Therefore, it is possible to obtain a measurement sensor that can realize from the irradiation of light of a specific wavelength to the measurement of a specific detection substance alone. Further, in the configuration of the measurement sensor described above, the light source, the semiconductor substrate, the metal layer, the reaction layer, and the electrode portion can be stacked and mounted on one chip, so that the relative arrangement of these configurations is easily fixed, The size of the measurement sensor can be easily reduced.

  In the measurement device and the measurement sensor according to the present invention, the metal layer includes a resonance part formed along the surface of the semiconductor substrate, and a current collection part connected to the plurality of resonance parts. Also good.

  According to the measurement device and the measurement sensor described above, when light of a predetermined wavelength is irradiated on the antenna portion of the metal layer and a reaction with a specific detection substance occurs in the reaction layer, resonance in each resonance portion is detected. Since the SPRs are combined and strengthened, the change in the surface current is increased, and highly sensitive measurement is performed.

  In the measuring device and the measuring sensor according to the present invention, the predetermined wavelength is 1 μm or more and 10 μm or less, the semiconductor substrate is made of n-type silicon, and the width of the resonance part is 0.5 μm or more and 5 μm or less. Also good.

  According to the measurement device and the measurement sensor described above, light having a wavelength of 1 μm or more and 10 μm or less passes through the semiconductor substrate made of n-type silicon, and the surface of the metal layer on the semiconductor substrate side (that is, the surface of the metal film) Is irradiated from the opposite surface) to the metal layer and the antenna portion. In addition, when the width of the resonance part is in the range of 0.5 μm or more and 5 μm or less, the resonance in the width direction of the resonance part and the SPR in the antenna part are well coupled. Thereby, the change of the surface current of the metal film due to the presence or absence of reaction in the reaction layer is greatly measured, and the measurement accuracy is improved.

  In the measurement device and the measurement sensor according to the present invention, a diffraction grating may be formed on the surface of the semiconductor substrate, and the metal layer and the antenna unit may be provided on the surface of the diffraction grating.

  According to the above-described measurement device and measurement sensor, the antenna unit is enlarged by being provided along the surface of the diffraction grating (that is, the upper surface side and the side surface side), and the measurement speed and sensitivity are increased.

  In the measurement device and the measurement sensor according to the present invention, a diffraction grating may be formed on the surface of the metal layer, and the antenna portion may be provided on the surface side of the metal layer.

  According to the measurement device and the measurement sensor described above, the antenna unit is enlarged by being provided along the surface of the diffraction grating (that is, the upper surface side and the side surface side of the antenna unit), and the measurement speed and sensitivity are increased. Furthermore, by forming the diffraction grating directly on the metal layer 10 in direct contact with the reaction layer 20, the designed shape, desired measurement accuracy, and sensor performance can be easily achieved.

  In the measurement device and the measurement sensor according to the present invention, at least one of a fine concave portion and a convex portion may be formed on the surface of the antenna portion, and the width of the concave portion and the convex portion is 1 of the predetermined wavelength. / 1000 or more and 1/10 or less are preferable.

  According to the measurement device and the measurement sensor described above, the reaction layer can be formed on the inner wall surface of the concave portion of the antenna portion or the surface of the convex portion, so that the antenna portion is enlarged and the measurement speed and sensitivity are increased.

  In the measurement device and the measurement sensor according to the present invention, a pillar may be formed on the surface of the semiconductor substrate, and the metal layer and the antenna unit may be provided on the surface of the pillar.

According to the measurement device and the measurement sensor described above, the resonance of the electromagnetic wave in the height direction of the pillar and the SPR can be combined, and the change in the surface current of the metal film due to the presence or absence of the reaction in the reaction layer is measured. Further, since the metal layer and the reaction layer are provided on the entire surface of the pillar, the antenna portion is enlarged, and the measurement speed and sensitivity of the measurement device and the measurement sensor are increased.

  According to the present invention, it is possible to provide a measuring apparatus that can perform stable measurement and can be easily reduced in size.

It is a top view of the device for measurement of a first embodiment concerning the present invention. It is a figure of the measuring device of 1st embodiment which concerns on this invention, and is sectional drawing seen by the arrow at the X1-X1 line | wire shown in FIG. It is an energy band figure of the device for measurement of a first embodiment concerning the present invention, and is a figure showing the state before reaction in a reaction layer arises. It is an energy band figure of the device for measurement of a first embodiment concerning the present invention, and is a figure showing a state when reaction in a reaction layer has occurred. It is a figure of the measurement sensor of 1st embodiment which concerns on this invention, and is sectional drawing corresponding to the case where an arrow is seen by the X1-X1 line | wire shown in FIG. It is a figure of the measuring device of 2nd embodiment which concerns on this invention, and is sectional drawing corresponding to the case where an arrow is seen by the X1-X1 line | wire shown in FIG. It is a figure of the measuring device of the modification of 2nd embodiment which concerns on this invention, and is sectional drawing corresponding to the case where it sees by the arrow at the X1-X1 line | wire shown in FIG. It is a figure of the measuring device of 3rd embodiment which concerns on this invention, Comprising: (a) is a perspective view, (b) is an expansion perspective view of the area | region Z shown to (a). It is a perspective view of the device for measurement of a 4th embodiment concerning the present invention. It is a figure of the measuring device of 4th embodiment which concerns on this invention, and is sectional drawing seen by the arrow at the X2-X2 line | wire shown in FIG. It is a schematic diagram showing the simulation model in an Example. It is a graph which shows the light absorption characteristic of the simulation model in an Example. It is a graph showing the response of the simulation model in an Example, and the wavelength dependence of energy. It is a plot figure which shows the electric field strength in the resonance point (1.94 * 10 < ¹⁴ > Hz) of the simulation model in an Example. It is a plot figure which shows the electric field strength in the preceding model similar to the simulation model in an Example. It is a graph which shows the light absorption characteristic in the resonance point (2.6 * 10 < ¹⁴ > Hz) of the simulation model in an Example. It is a plot figure which shows the electric field strength in the resonance point (2.6 * 10 < ¹⁴ > Hz) of the simulation model in an Example. It is a graph which shows the light absorption characteristic at the time of changing the refractive index of the dielectric material (Air) of the simulation model in an Example. It is a plot figure which shows the electric field strength at the time of changing the refractive index of the dielectric material (Air) of the simulation model in an Example. It is another plot figure which shows the electric field strength at the time of changing the refractive index of the dielectric material (Air) of the simulation model in an Example. It is another plot figure which shows the electric field strength at the time of changing the refractive index of the dielectric material (Air) of the simulation model in an Example.

  Embodiments of a measurement device and a measurement sensor according to the present invention will be described below with reference to the drawings. The drawings used in the following description are schematic, and the length, width, thickness ratio, and the like are not necessarily the same as the actual ones, and can be changed as appropriate.

(First embodiment)
[Measurement device configuration]
As shown in FIGS. 1 and 2, the measurement device 100 </ b> A of the first embodiment includes at least a semiconductor substrate 5 that can transmit light L having a predetermined wavelength, and a metal layer stacked on the surface 5 b of the semiconductor substrate 5. 10 and a reaction layer 20 formed on the surface 10 b of the metal layer 10. The measurement device 100 </ b> A includes an electrode unit 30 that electrically connects the metal layer 10 and the back surface (surface on the light source side of the dielectric substrate) 5 a of the dielectric substrate 5.

The semiconductor substrate 5 is made of a semiconductor that can transmit light L having a predetermined wavelength. Specifically, the transmittance of the light L in the semiconductor substrate 5 is preferably, for example, 90% or more, more preferably 92% or more, and further preferably 95% or more. In the measurement device 100A, the semiconductor substrate 5 is
<1> constituting a propagation region of the light L <2> determining SPR resonance conditions with the metal layer 10 <3> three main functions of forming a Schottky barrier at the interface 8 with the metal layer 10 Have both. In addition, since the measurement device 100 </ b> A includes the electrode unit 30, the semiconductor substrate 5 also plays a role of configuring the electrode unit 30.

  The metal layer 10 includes an antenna unit 15 that causes SPR when light L is applied to the metal layer 10 from the back surface 10 a side through the semiconductor substrate 5. The antenna unit 15 is provided on the surface 10 b side of the metal layer 10. The antenna unit 15 functions as an antenna that captures the SPR generated between the reaction layer 20 and is formed in a portion of the metal layer 10 on the reaction layer 20 side.

  The metal layer 10 of the first embodiment includes a plurality of resonance portions 11 formed at intervals s in the D2 direction along the surface 5b of the semiconductor substrate 5, and a current collector portion 12 connected to the resonance portion 11. I have. In such a configuration, the light L is irradiated to excite electrons inside each resonance unit 11, and resonance occurs along the D2 direction (or the direction opposite to the D2 direction). Hereinafter, this is referred to as dipole resonance) and SPR generated between the antenna unit 15 and the reaction layer 20 is coupled.

  The resonance part 11 is formed to have a predetermined width d in the direction D2. That is, in the D2 direction, a plurality of metal layers 10 having a width d are formed at intervals s. The current collector 12 is formed so as to connect one end of the plurality of resonance portions 11 in the D1 direction (the upper end in FIG. 1) along the D2 direction. That is, as shown in FIG. 1, the metal layer 10 of the first embodiment is formed in a comb shape in plan view.

  The material of the metal layer 10 is not particularly limited as long as it is a metal that can generate a surface current due to SPR as described above. A suitable material for the metal film 10 is gold (Au). Gold is preferable because it has excellent conductivity and matures a technique for forming a material constituting the reaction layer 20 on the surface 10b such as the antibody 22 or the like.

  The reaction layer 20 is configured to be able to react with a specific detection substance (that is, a measurement target substance). As the materials and materials constituting the reaction layer 20, materials that can be formed on the surface 10b of the metal layer 10 according to a specific detection material are appropriately employed.

  In the first embodiment, for example, antigen P is assumed as a specific detection substance. The reaction layer 20 is composed of an antibody 22 that causes an antigen-antibody reaction with the antigen P. One end of the antibody 22 is fixed to the surface 10 b of the metal layer 10, that is, the antenna unit 15, and the other end of the antibody 22 is open. Specifically, at least one or more antibodies 22 are aligned and fixed along the surface 10b in a state where the stationary region on one end side of the antibody 22 is in contact with the surface 10b of the metal layer 10, and the other end side of the antibody 22 is The variable region (that is, the region that recognizes and binds specifically to the antigen P and generates an antigen-antibody reaction) is open.

  In the configuration as described above, when the sample Q is dropped into the reaction unit 20 and the antigen Q is included in the sample Q, the antigen-antibody reaction occurs due to the binding of the antigen P to the variable region of the antibody 22. The refractive index of the antibody 22 and the antenna unit 15 in which the antigen-antibody reaction has occurred changes, and acts on the dipole resonance and SPR in the resonance unit 11. Thus, the antenna unit 15 captures the change in the refractive index described above.

The electrode unit 30 includes a terminal 32 extending along the D2 direction from the current collecting unit 12 of the metal layer 10, a terminal 34 disposed on the back surface 5a of the semiconductor substrate 5, and a line connecting the terminals 32 and 34. 36. The surface current (I _SC ) collected in the current collector 12 of the metal layer 10 can be displayed on an ammeter 38 provided on the line 36, a monitor, or the like.

[Principle of measurement device]
In the measurement device 100A of the first embodiment, the terminal 34 of the electrode unit 30, the semiconductor substrate 5, and the terminal 32 of the electrode unit 30 are sequentially stacked along the direction of advance in the D1 direction, which is illustrated in FIG. An energy band structure is created. 3 and 4, it is assumed that the semiconductor substrate 5 is an n-type semiconductor. The energies E _V , E _F , E _C , and VL represent the energy level of the valence band, the Fermi level, the energy level of the conduction band, and the vacuum level, respectively.

  Since the Schottky barrier W1 is formed at the interface 8 formed by joining the terminal 32 of the electrode unit 30 (that is, the metal layer 10) and the semiconductor substrate 5, the free electrons e that are not excited in the metal layer 10 are The Schottky barrier 1 cannot be exceeded and remains inside the metal layer 10.

  When the antigen P binds to the antibody 22 (see FIG. 2) and SPR occurs between the reaction layer 20 and the metal layer 10 (S in FIG. 2 etc.), as shown in FIG. The free electrons e are excited, get over the Schottky barrier W1, and diffuse in a direction opposite to the D1 direction (that is, a direction from the metal layer 10 toward the semiconductor substrate 5).

  A Schottky barrier W <b> 2 is formed at an interface formed by bonding between the semiconductor substrate 5 and the terminal 34 of the electrode unit 30. Free electrons e excited by the SPR and overcoming the Schottky barrier W1 diffuse toward the Schottky barrier W2. Basically, free electrons e cannot get over Schottky barrier W2 as indicated by arrow Y1 unless excited by energy corresponding to the height of Schottky barrier W2. Therefore, an impurity is doped on the side opposite to the metal layer 10 in the semiconductor substrate 5 of the first embodiment (that is, the back surface 5a side), and the semiconductor substrate 5 and the terminal 34 are in ohmic contact. Further, since the semiconductor substrate 5 is highly doped with impurities, the width k of the Schottky barrier W2 is narrow for the free electrons e. Furthermore, since the material of the terminal 34 is selected such that the Schottky barrier W2 between the semiconductor substrate 5 and the terminal 34 is low, the free electrons e can tunnel the Schottky barrier W2 as indicated by the arrow Y2. .

  As the free electrons e diffuse, the holes h diffuse from the valence band of the semiconductor substrate 5 toward the inside of the metal layer 10. According to such a principle, a surface current is generated (or changes) in the metal layer 10 when SPR occurs. By measuring the increase / decrease in the surface current taken out to the electrode part 30, the presence / absence of the antigen-antibody reaction and the presence / absence or concentration of the antigen P in the sample Q are detected.

  The magnitude of the surface current of the metal layer 10 varies depending on the wavelength of the light L depending on the presence / absence of the antigen-antibody reaction, the presence / absence and concentration of the antigen P in the sample Q, and the resonance conditions of the SPR. Therefore, the wavelength of the light L can be adjusted by predicting the magnitude of the surface current for each wavelength in advance by numerical simulation in consideration of the above-described conditions and the like. In other words, the change of the surface current can be measured by adjusting the wavelength of the light L (predetermined wavelength) in consideration of the result of the numerical simulation described above.

  Based on the above-described components and principles, suitable conditions and the like of each component of the measurement device 100A will be described.

In the measurement device 100A, conditions such as the material and shape of each component are appropriately set according to the flow described below.
(F1); The antibody 22 is selected in accordance with the antigen P to be measured, and the metal of the antenna part 15 and the metal layer 10 capable of forming the antibody 22 and capable of causing SPR is selected (F2); Setting the wavelength (wavelength band) of the light L that causes SPR between the reaction layer 20 (antibody 22) and the antenna unit 15 (F3); a metal that can transmit the light L and constitute the metal layer 10; SPR is generated and the material of the semiconductor substrate 5 forming the Schottky barrier W1 is selected (F4); the length, width, thickness and the like of each component are set as appropriate. However, in (F2) and (F3) For flows, the order may change. In addition, the flow (F4) may be performed in the flows (F1), (F2), and (F3).

  From the viewpoint of the flow (F1), the antibody 22 constituting the reaction layer 20 can be easily formed on the surface 10b of the metal layer 10 as described above. Therefore, Au is preferable as the metal of the metal layer 10. When the metal layer 10 is made of Au, the antenna portion 15 and the metal layer 10 forming the interface 8 can be made of the same metal Au.

  For example, the width d of the resonance portion 11 of the metal layer 10 is preferably 0.5 μm or more and 5 μm or less. When the width d of the resonance portion 11 is within the above-described range, the SPR excitation condition and the degree of dipole resonance coupled with the SPR are improved. The thickness of the metal layer 10 is preferably 50 nm or more and 200 nm or less.

  From the viewpoint of the flows (F2) and (F3), the predetermined wavelength of the light L is preferably, for example, from 1 μm to 10 μm. The wavelength of the light L is not particularly limited as long as SPR can be caused between the reaction layer 20 and the antenna unit 15 as described above. A suitable material for the semiconductor substrate 5 is silicon (Si) as an n-type semiconductor that can transmit light L having a wavelength of 1 μm to 10 μm.

  As shown in FIGS. 3 and 4, the terminal 34 of the electrode unit 30 forms a Schottky barrier W <b> 2 at the interface with the semiconductor substrate 5. The terminal 34 is made of, for example, aluminum (Al) or titanium from the viewpoint of enabling free electrons e to be tunneled to the semiconductor substrate 5 made of n-type Si and allowing the surface current of the metal layer 10 to be taken out smoothly. (Ti), chromium (Cr), etc. are mentioned.

Further, as described above, impurities are doped on the back surface 5a side of the semiconductor substrate 5 from the viewpoint that the free electrons e can be tunneled and the surface current of the metal layer 10 can be taken out smoothly. As the impurities, those known as dopants for n-type semiconductors can be used, and examples include phosphorus (P), arsenic (As), and antimony (Sb). The doping concentration can be set to about 10 ²⁰ atoms / cm ³ , for example, but can be appropriately adjusted in consideration of the height of the Schottky barrier W 2 and the like. When the thickness of the semiconductor substrate 5 is about several hundred μm, the depth that the impurity penetrates from the back surface 5a (that is, the thickness of the doped region 5d shown in FIGS. 2 to 4) may be about 100 nm, for example.

[Configuration of measurement sensor]
Next, the measurement sensor according to the first embodiment will be described. In the measurement sensor according to the first embodiment, the description common to the measurement device 100A according to the first embodiment is omitted, and different contents are described below. Moreover, the same code | symbol is attached | subjected about the component which is common in the component of the measurement device 100A of 1st embodiment among the components of the measurement sensor of 1st embodiment.

  As shown in FIG. 5, the measurement sensor 102 according to the first embodiment includes a light source 3 stacked on the back surface 5 a of the semiconductor substrate 5 in addition to the components of the measurement device 100 </ b> A.

  The light source 3 emits light L having a predetermined wavelength along the direction D1 from the light emitting surface 3m. The light emitting surface 3m of the light source 3 and the central portion 5m of the back surface 5a of the semiconductor substrate 5 are in contact with each other without a gap. The light source 3 is not particularly limited as long as it emits light L having a predetermined wavelength. As the light source 3, for example, a vertical cavity surface emitting laser (VCSEL) is suitable. By using a VCSEL for the light source 3, it is easy to stack on the dielectric substrate 5, and since the light emitting surface 3m is along the D2 direction and the light emitting direction of the light L is along the D1 direction, the thickness of the light source 3 in the D1 direction is reduced. Can do.

  In the measurement sensor 102 illustrated in FIG. 5, the width of the light L emitted from the light source 3 in the direction D2 (that is, the direction orthogonal to the direction D1 and along each of the bottom surface 5a and the surface 5b of the semiconductor substrate 5) is a light emitting surface. It is assumed that the distance increases from 3 m toward D1. Therefore, the width of the light emitting surface 3m of the light source 3 in the direction D2 is set to be narrower than the width of the bottom surface 5a of the semiconductor substrate 5.

[Principle of measurement sensor]
The principle of the measurement sensor 102 is the same as that of the measurement device 100A except that the light L is emitted from the light source 3 and directly enters the semiconductor substrate 5 from the back surface 5a.
Further, suitable conditions and the like of each component in the measurement sensor 102 are the same as those of the measurement device 100A.

[Effects of measuring device and measuring sensor]
According to the measurement device 100A and the measurement sensor 102 of the first embodiment described above, when the antenna unit 15 is irradiated with the light L, the dipole resonance and the SPR in the resonance unit 11 are combined to strengthen each other, and the metal The surface current generated in the resonance part 11 of the layer 10 is efficiently collected in the current collecting part 12. By confirming the current value taken out to the electrode unit 30, the presence or absence of the antigen P reacted in the reaction layer 20 and the concentration of the antigen P can be easily measured.

  Further, according to the measurement device 100A and the measurement sensor 102, the semiconductor substrate 5, the metal layer 10, and the reaction layer 20 can be stacked on one chip, and the relative arrangement of these components can be easily fixed. In addition, since the light L is applied to the metal layer 10 from the back surface 10b side, more stable measurement can be performed without causing almost any interference between the light L and the reaction layer 20, the antigen P, the sample Q, and the like. . Further, by laminating and mounting the semiconductor substrate 5, the metal layer 10, and the reaction layer 20 on one chip, it is not necessary to attach a large device such as a rotating optical system, and the measurement device 100A and the measurement sensor 102 can be downsized. Can be easily achieved.

  In the measuring device 100A, by providing the electrode portion 30, the surface current generated in the metal layer 10 is taken out to the line 36 via the terminals 32 and 34, and an ammeter 38 or a monitor device provided on the line 36 is used. Can be measured.

  According to the measurement sensor 102, the light source 3 is stacked on the back surface 5 b of the semiconductor substrate 5, and the electrode portion 30 that connects the metal layer 10 and the back surface 5 a of the semiconductor substrate 5 is provided, so Measurement up to P can be realized by itself. Further, according to the measurement sensor 102, in addition to the components common to the measurement device 100A, the light source 3 and the electrode unit 30 are stacked and mounted on one chip, so that the relative arrangement of these components can be easily fixed. In addition, the measurement sensor 102 can be easily reduced in size.

  Further, according to the measurement device 100A and the measurement sensor 102, since the metal layer 10 includes the plurality of resonance portions 11 and the current collecting portion 12, when an antigen-antibody reaction between the antibody 22 and the antigen P occurs. The dipole resonance in each resonance portion 11 and the SPR in the reaction layer 20 can be combined. Thereby, since the resonance phenomenon strengthens each other, the change in the surface current can be increased and highly sensitive measurement can be performed.

  In particular, according to the measurement device 100A and the measurement sensor 102, the wavelength of the light L is in the range of 1 μm or more and 10 μm or less, and the semiconductor substrate 5 is made of n-type Si, so that the light L can be satisfactorily received by the semiconductor substrate 5 The light L can be applied to the metal layer 10 and the antenna unit 15 from the back surface 10a. Further, by setting the width d of the resonance part 11 within the range of 0.5 μm or more and 5 μm or less, the resonance in the D2 direction of the resonance part 11 and the SPR in the antenna part 15 can be coupled well. Thereby, the change of the surface current with and without the antigen-antibody reaction in the reaction layer 20 can be increased, and the measurement accuracy can be improved.

  Therefore, according to the measurement device 100A and the measurement sensor 102, stable measurement can be performed and downsizing can be easily achieved.

[Modification]
Although the first embodiment to which the present invention is applied has been described in detail, the measurement device 100A and the measurement sensor 102 according to the first embodiment are within the scope of the gist of the present invention described in the claims. Various modifications and changes are possible. In addition, the modification of 1st embodiment is not limited to the following content.

  For example, in the measurement device and the measurement sensor according to the present invention, the reaction layer 20 has been described as having a large number of antibodies 22 arranged. However, depending on the change of a specific detection substance, the reaction layer 20 may be a Nafion or the like. It may be changed to an ion recognition substance, lipid, self-assembled monolayer (SAM), or the like. As described above, as the material constituting the reaction layer 20, a material that can be formed on the surface 10b of the metal layer 10 according to a specific detection material is appropriately adopted.

  Further, the type of metal constituting the antenna part 15 and the metal constituting the Schottky barrier W1 at the interface 8 with the semiconductor substrate 5 (part of the metal layer 10 other than the antenna part 15, hereinafter referred to as a Schottky barrier constituting metal) May be different. As an example, Cr or Ti may be adopted as the Schottky barrier constituent metal, Au may be adopted as the metal constituting the antenna unit 15, and the metal layer 10 may be composed of a laminate of Cr, Ti and Au. As a result, the energy level of the Schottky barrier W1 at the interface 8 can be lowered, and a small SPR can be measured.

  Further, the resonance part 11 may be formed alone along the surface 5 b of the semiconductor substrate 5.

  Further, the terminal 34 of the electrode unit 30 can be omitted, and the end of the line 36 on the semiconductor substrate 5 side may be directly connected to the semiconductor substrate 5. Moreover, the structure of the electrode part 30 can be changed suitably, and the surface current of the metal layer 10 should just be detected. For example, the line 36 may be connected to a line such as a device other than the measurement device or the measurement sensor, or a power receiving unit.

  Further, instead of the electrode unit 30, a circuit or a power receiving unit such as a device other than the measurement device or the measurement sensor is directly connected to the semiconductor substrate 5 and the terminal 32 (that is, the metal layer 10) of the measurement device 100 </ b> A or the measurement sensor 102. It may be connected to each of.

  The semiconductor substrate 5 may be made of a p-type semiconductor. When the semiconductor substrate 5 is composed of a p-type semiconductor, the majority carriers in FIGS. 3 and 4 become holes h instead of free electrons e.

  Further, an optical laminated structure having a desired function is formed on the back surface 5a of the semiconductor substrate 5 (between the light emitting surface 3m of the light source 3 and the central portion 5m of the back surface 5a of the semiconductor substrate 5). It may be provided. Examples of such an optical laminated structure include those having functions of a band pass filter, an amplification filter, and a wavelength conversion filter, but are not particularly limited thereto. As an example, when the light emission mechanism of the light source that emits the light L covers a wide band including a predetermined wavelength, the light is irradiated on the back surface 5 a of the semiconductor substrate 5. A dielectric multilayer film having a function of transmitting only the light L having a predetermined wavelength from the light emitted from the light source is provided in the region (and the region excluding the end portion 5f where the terminal 34 of the electrode portion 30 is disposed). Can do.

  In the configuration of the measuring device 100 illustrated in FIGS. 1 and 2, the back surface 5a of the semiconductor substrate 5 is parallel to the front surface 5b, and the light L propagates inside the semiconductor substrate 5 from the back surface 5a side. It is assumed that it reaches the 5b side. However, the back surface 5a of the semiconductor substrate 5 is inclined with respect to the front surface 5b in the same sectional view as in FIG. 2, and is formed so as to be separated from the front surface 5b as it proceeds from one side of the back surface 5a toward the other along the direction D2. May be. Then, the light L is incident on the semiconductor substrate 5 from the side surface on the side where the front surface 5b and the back surface 5a are largely separated in the above-described cross-sectional view, and propagates through the semiconductor substrate 5 and is reflected by the inclined back surface 5a. After that, it is also possible to reach the surface 5b side. In such a configuration, from the viewpoint of reflecting the light L with high reflectance on the back surface 5a, a mirror made of a metal film such as Al or a dielectric multilayer film may be provided on the back surface 5a.

  Further, in the configuration of the measurement sensor 102 illustrated in FIG. 5, the width in the D2 direction of the central portion 5m of the bottom surface 5a of the semiconductor substrate 5 (that is, the width in contact with the light emitting surface 3m of the light source 3) is as follows. It is set appropriately in consideration of the light emission distribution and the like. When the width of the light L in the D2 direction hardly changes as it proceeds from the light emitting surface 3m to the D1 direction, the light emitting surface 3m of the light source 3 is substantially the entire back surface 5a (excluding the end portion 5f) of the dielectric substrate 5. It is preferable that they are in contact with each other.

(Second embodiment)
Next, the measurement device and measurement sensor of the second embodiment will be described. Note that, in the components of the measurement device and the measurement sensor of the second embodiment, the same components as those of the measurement device 100A and the measurement sensor 102 of the first embodiment are denoted by the same reference numerals, and description thereof is omitted. To do.

[Measurement device configuration]
As illustrated in FIG. 6, the measurement device 100 </ b> B of the second embodiment includes the same components as the measurement device 100 </ b> A of the first embodiment. However, the surface 5b of the semiconductor substrate 5 is not a smooth surface, and the diffraction grating 14 is provided on the surface 5b along the direction D2.

  In the second embodiment, the metal layer 10 is provided over the entire surface 5b of the semiconductor substrate 5 with a substantially uniform thickness without including a plurality of resonance portions. The antenna unit 15 substantially overlaps the metal layer 10 and is provided over the entire surface 5 b of the semiconductor substrate 5. The reaction layer 20 is formed over the entire surface 10 b of the metal layer 10. Thus, the antibody 22 constituting the reaction layer 20 is provided on the side surface in addition to the upper surface of the metal layer 10.

[Principle of measurement device]
The principle of the measuring device 100B is the same in that the energy band structure shown in FIG. 3 is formed as described in the first embodiment. However, since the metal layer 10 of the measuring device 100B shown in FIG. 6 does not include the resonance part 11, no dipole resonance occurs. Instead, since the diffraction grating 14 is formed on the surface 5b side of the semiconductor substrate 5, SPR generated between the antenna unit 15 and the reaction layer 20 is excited by the satisfaction of conditions described later.

Here, the wave number k _S of SPR is determined by the dielectric constant ε (ω) of the metal (for example, Au) constituting the metal layer 10, and is expressed by the following equation (1).

In the equation (1), ω represents the angular frequency of the light L, and ε _m represents the dielectric constant of the antibody 22 constituting the reaction layer 20.

D2 direction of light L (that is, parallel to the surface of the diffraction grating 14) incident on the diffraction grating 14 at an incident angle θ _S (θ = 0 ° when parallel to the D1 direction as indicated by the arrow of the light L shown in FIG. 6). The wave number k _{0 in the} right direction is expressed by the following equation (2).

  In equation (2), c represents the speed of light. Since the wave number of the incident light is increased / decreased by the diffraction order n upon receiving the diffraction, the order of the diffracted light involved in the SPR is expressed by the following equation (3).

  In the equation (3), t represents the pitch of the diffraction grating 14.

  Since SPR occurs when the wave numbers of the diffracted light by the diffraction grating 14 and the SPR coincide at the same frequency, the coupling condition of the diffracted light and the SPR is expressed by the following equation (4).

  When the above-described binding condition is satisfied, SPR occurs, and a difference in dielectric constant of a specific detection substance, that is, antigen P appears as a change in the incident angle of the SPR antenna unit 15 and the wavelength of the SPR. Reflected in the surface current.

  Accordingly, when the antigen P binds to the antibody 22 and SPR occurs between the reaction layer 20 and the metal layer 10, the free electrons e inside the metal layer 10 are excited as shown in FIG. It overcomes the barrier W1 and diffuses in the direction opposite to the direction D1 (that is, the direction from the metal layer 10 toward the semiconductor substrate 5). According to such a principle, a surface current is generated (or changes) in the metal layer 10 when SPR occurs. Similar to the first embodiment, the presence or absence of an antigen-antibody reaction and the presence or absence or concentration of the antigen P in the sample Q are detected by measuring the increase or decrease in the surface current extracted to the electrode unit 30.

  Suitable conditions and the like for each component in the measurement device 100B are basically the same as those for each component common to the measurement device 100A. However, the pitch t of the diffraction grating 14 is preferably 0.5 μm or more and 5 μm or less if the wavelength of the light L is in the range of 1 μm or more and 10 μm or less. When the pitch t of the diffraction grating 14 is within the above-described range, the diffracted light by the diffraction grating 14 and the SPR are well coupled. The height (thickness) of the diffraction grating 14 is preferably 50 nm or more and 200 nm or less.

  The thickness of the metal layer 10 is preferably 50 nm or more and 200 nm or less.

[Configuration of measurement sensor]
Although not shown, the measurement sensor of the second embodiment includes the same light source as the light source 3 of the measurement sensor 102 of the first embodiment on the back surface 5a of the semiconductor substrate 5 of the measurement device 100B shown in FIG. Is.

[Principle of measurement sensor]
The principle of the measurement sensor of the second embodiment is the same as that of the measurement device 100B except that the light L is emitted from a light source provided on the back surface 5a of the semiconductor substrate 5 and directly enters the semiconductor substrate 5 from the back surface 5a. It is.

[Effects of measuring device and measuring sensor]
According to the measurement device 100B and the measurement sensor of the second embodiment described above, substantially the same effect as that of the measurement device 100A and the measurement sensor 102 of the first embodiment can be obtained. However, in the configuration of the measurement device 100B and the measurement sensor of the second embodiment as described above, the measurement device 100A and the measurement sensor 102 excite free electrons e by combining dipole resonance and SPR, and shot In contrast to exceeding the key barrier W1, the free electron e is excited by coupling the diffracted light by the diffraction grating 14 and the SPR to exceed the Schottky barrier W1.

  In the measurement device and the measurement sensor to which the present invention is applied, basically, the rate at which the antigen P (specific detection substance) is adsorbed on the reaction film 20 is large in the surface area where the reaction film 20 and the antigen P are in contact with each other. That is, it depends on the width of the antenna unit 15. According to the measurement device 100B and the measurement sensor of the second embodiment, since the metal layer 10 and the reaction layer 20 are provided on the entire surface of the diffraction grating 14, the antenna unit 15 is compared with the measurement device 100A and the measurement sensor 102. Is expanded. Thereby, the speed at which the antigen P is adsorbed to the reaction film 20 can be increased, and the measurement speed and sensitivity of the measurement device 100B and the measurement sensor of the second embodiment can be increased.

[Modification]
As described above, the second embodiment to which the present invention is applied has been described in detail, but the measurement device 100B and the measurement sensor of the second embodiment are within the scope of the gist of the present invention described in the claims. Various modifications and changes similar to those of the measurement device 100A and the measurement sensor 102 of the first embodiment are possible.

  Further, from the same viewpoint of increasing the surface area where the reaction film 20 and the antigen P are in contact with each other, as shown in FIG. 7, the surface 5b of the semiconductor substrate 5 is a smooth surface and the surface 10b of the metal layer 10 is uneven. A diffraction grating 14 may be provided. In the measurement device 100 </ b> C and the measurement sensor (not shown) configured as described above, the upper surface side and the side surface side of the metal layer 10 are antenna portions 15. Therefore, according to the measurement device 100C and the measurement sensor according to the modification of the second embodiment, the antenna unit 15 is provided in accordance with the concavo-convex shape of the diffraction grating 14 as in the measurement device 100B and the measurement sensor of the second embodiment. Since it can be enlarged, the measurement speed and sensitivity can be increased.

  Furthermore, in terms of manufacturing, the measurement device 100C and the measurement sensor of the modified example of the second embodiment have an advantage that it is easy to realize the shape as designed, compared to the measurement device 100B and the measurement sensor of the second embodiment. Have. For example, it is possible to easily achieve the desired measurement accuracy and sensor performance by adjusting the material, shape, dimensions, etc. of each component according to the purpose of measurement using optical simulation and processing as designed. it can.

(Third embodiment)
Next, the measurement device and measurement sensor of the third embodiment will be described. Note that, in the constituent elements of the measurement device and the measurement sensor of the third embodiment, the same reference numerals are given to the same constituent elements as those of the measurement devices 100A and 100B and the measurement sensor 102 of the first embodiment and the second embodiment. A description thereof will be omitted.

[Measurement device configuration]
As shown in FIGS. 8A and 8B, the measurement device 100D of the third embodiment includes the same components as the measurement device 100B of the second embodiment. However, a plurality of fine concave portions 40 are provided on the surface 5 b of the semiconductor substrate 5. Specifically, a fine recess 40 is formed on the surface 5 b of the semiconductor substrate 5, and the metal layer 10 and the antenna portion 15 have a substantially uniform thickness over the entire surface 5 b including the inner wall surface 42 of the recess 40. Is provided. As a result, a fine recess 40 is formed on the surface of the antenna unit 15.

  In the third embodiment, as shown in FIG. 8 (b), the antibody 22 constituting the reaction layer 20 has an inner wall surface 42 of the recess 40 (that is, the surface of the antenna unit 15) in addition to the upper surface and side surfaces of the metal layer 10. The whole). In FIG. 8A, illustration of individual antibodies 22 constituting the reaction layer 20 is omitted. Further, in FIG. 8B, illustration of the antigen P and the sample Q adsorbed to at least some of the antibodies 22 among the plurality is omitted.

  The concave portion 40 has a circular opening, and is narrowed so that the opening diameter of the concave portion 40 decreases as it proceeds in the direction opposite to the direction D1 (that is, toward the bottom of the concave portion 40). The concave portion 40 is a fine structure formed for the purpose of enlarging the antenna portion 15 without greatly affecting the diffraction of the light L by the diffraction grating 14. For the above-described purpose, the opening diameter r40 of the recess 40 is preferably 1/1000 or more of the wavelength of the light L due to manufacturing restrictions, and 1/10 of the wavelength of the light L in order to prevent scattering and diffraction of the light L. The following is preferable. If the wavelength of the light L is in the range of 1 μm or more and 10 μm or less as described above, the opening diameter r40 is preferably 1 nm or more and 1 μm or less. In plan view, the distance (interval) g40 between the centers of the adjacent recesses 40 is preferably 2 nm or more and 20 μm or less. The depth of the recess 40 is appropriately set in consideration of the minimum dimension at which the antibody 22 can be deposited, the deposition method, and the like.

[Principle of measurement device]
The principle of the measuring device 100D is the same as that of the measuring device 100B described in the second embodiment. As described above, since the fine concave portion 40 is very small compared to the wavelength of the light L, there is no influence of the diffraction of the light L by the concave portion 40, and the coupling condition of the above-described formula (4) is satisfied. Occasionally, SPR occurs, and a difference in dielectric constant of a specific detection substance appears as a change in the incident angle of the SPR antenna 15 and the wavelength of the SPR, and is reflected in the surface current of the metal layer 10.

  Suitable conditions and the like for each component in the measurement device 100D are basically the same as those for each component common to the measurement device 100B. Suitable dimensions and the like of the fine recess 40 are also as described above.

[Configuration of measurement sensor]
Although not shown, the measurement sensor of the third embodiment uses a light source similar to the light source 3 of the measurement sensor 102 of the first embodiment on the back surface 5a of the semiconductor substrate 5 of the measurement device 100D shown in FIG. It is what it has.

[Principle of measurement sensor]
Regarding the principle of the measurement sensor of the third embodiment, the light L is irradiated from a light source provided on the back surface 5a of the semiconductor substrate 5 and directly incident on the semiconductor substrate 5 from the back surface 5a. This is the same as the device 100B for use.

[Effects of measuring device and measuring sensor]
According to the measurement device 100D and the measurement sensor of the third embodiment described above, substantially the same effect as that of the measurement device 100A and the measurement sensor 102 of the second embodiment can be obtained.

  Moreover, according to the measurement device 100D and the measurement sensor of the third embodiment, a plurality of fine recesses 40 are formed on the surface 5b of the semiconductor substrate 5, and the metal layer 10 and the reaction layer 20 are formed on the surface 5b of the semiconductor substrate 5. In addition, since it is also provided on the inner wall surface of the recess 40, the antenna unit 15 is further enlarged compared to the measurement device 100B and the measurement sensor of the second embodiment. Thereby, the speed at which the antigen P is adsorbed to the reaction film 20 is increased as compared with the measurement device 100B and the measurement sensor of the second embodiment, and the measurement speed and sensitivity of the measurement device 100D and the measurement sensor of the third embodiment are further increased. be able to.

[Modification]
As described above, the third embodiment to which the present invention is applied has been described in detail, but the measurement device 100D and the measurement sensor of the third embodiment are within the scope of the gist of the present invention described in the claims. Various modifications and changes similar to those of the measurement device 100A and the measurement sensor 102 of the first embodiment and the measurement device 100B and the measurement sensor of the second embodiment are possible.

  In addition, the concave portion 40 is not limited to the one that becomes narrower as it goes to the circular opening and the bottom as described above, but may be capable of expanding the area where the antenna portion 15 and the reaction layer 20, that is, the antibody 22 are formed. There is no particular limitation. For example, the planar view shape of the opening of the recess 40 may be a rectangle, a polygon, a star, or the like. The opening width of the recessed portion 40 may be substantially constant from the upper end to the bottom end of the recessed portion 40 along the direction D1, and may increase as it goes to the bottom, contrary to the example of the third embodiment described above.

  In addition, a convex portion that protrudes in the D1 direction may be formed on the surface 15b of the antenna portion 15 in place of the concave portion 40. However, the width of the convex portion is preferably 1/1000 or more of the wavelength of the light L due to manufacturing restrictions, and is preferably 1/10 or less of the wavelength of the light L in order to prevent scattering and diffraction of the light L. . Furthermore, the concave portion 40 and the convex portion may be mixed on the surface 15 b of the antenna portion 15.

  Further, the concave portion 40 or the convex portion is used for the measurement device 100A according to the first embodiment and the surface of the antenna portion 15 of the measurement sensor 102 (that is, the surface 10b of the metal layer 10) or the measurement according to the fourth embodiment described below. You may form in the surface of the antenna part 15 of the device 100E and a measurement sensor. That is, if the number of deposited antibodies 22 per unit area is substantially the same, the antenna portion 15 is more formed when the recesses 40 and the protrusions are formed than when the recess 40 and the protrusions are not formed. In addition, since the surface area of the reaction layer 20 is enlarged, the effect of increasing the measurement speed and sensitivity can be obtained. The presence or absence of the concave and convex portions of the metal layer 10 where the concave portions 40 and the convex portions are formed, the shape of the metal layer 10 and the like are as follows. There is no particular limitation. Even if the metal layer 10 includes the resonance part 11 as in the first embodiment, it is preferable that the concave part 40 and the convex part do not affect the light L by diffraction or the like. The preferable shape and the preferable range of the dimensions of the convex portion are the same as those described in the third embodiment and the modification described above.

(Fourth embodiment)
Next, a measurement device and a measurement sensor according to the fourth embodiment will be described. Note that, in the components of the measurement device and the measurement sensor of the fourth embodiment, the same components as those of the measurement device 100A and the measurement sensor 102 of the first embodiment are denoted by the same reference numerals, and description thereof is omitted. To do.

[Measurement device configuration]
As shown in FIGS. 9 and 10, the measurement device 100E of the fourth embodiment includes the same components as the measurement device 100A of the first embodiment. However, a plurality of pillars 18 are provided on the surface 5 b of the semiconductor substrate 5. Specifically, a plurality of pillars 18 are formed on the surface 5 b of the semiconductor substrate 5, and the metal layer 10 and the antenna unit 15 are provided with a substantially uniform thickness over the entire surface 5 b including the surface of the pillar 18. It has been. Thereby, a plurality of pillars 48 are formed on the upper part of the measuring device 100E.

  The pillar 48 is formed in a substantially cylindrical shape. The height of the pillar 48 is set as appropriate, and can be set to, for example, 1/6 or more and 2/3 or less of the value of (the predetermined wavelength of the light L / the refractive index of the material constituting the pillar 48).

[Principle of measurement device]
The principle of the measuring device 100E is the same in that the energy band structure shown in FIG. 3 is formed as described in the first embodiment. However, in the fourth embodiment, SPR generated between the antenna unit 15 and the reaction layer 20 is excited by resonance of electromagnetic waves in the height direction (that is, D1 direction) in the pillar 48 instead of dipole resonance. .

  Resonance of electromagnetic waves in the height direction in the pillar 48 occurs, and the surface current of the metal layer 10 changes when SPR occurs.

  Therefore, when the light L is irradiated to the pillar 48, the antigen P binds to the antibody 22, and SPR occurs between the reaction layer 20 and the metal layer 10, as shown in FIG. The free electrons e are excited, get over the Schottky barrier W1, and diffuse in a direction opposite to the D1 direction (that is, a direction from the metal layer 10 toward the semiconductor substrate 5). According to such a principle, a surface current is generated (or changes) in the metal layer 10 when SPR occurs. Similar to the first embodiment, the presence or absence of an antigen-antibody reaction and the presence or absence or concentration of the antigen P in the sample Q are detected by measuring the increase or decrease in the surface current extracted to the electrode unit 30.

[Effects of measuring device and measuring sensor]
According to the measurement device 100E and the measurement sensor of the fourth embodiment described above, substantially the same effects as those of the measurement device 100A and the measurement sensor 102 of the first embodiment can be obtained. However, as described above, in the configuration of the measurement device 100E and the measurement sensor of the fourth embodiment, the free electron e is excited by coupling the resonance of the electromagnetic wave in the pillar 48 and the SPR, and exceeds the Schottky barrier W1. .

  Further, according to the measurement device 100E and the measurement sensor of the fourth embodiment, since the metal layer 10 and the reaction layer 20 are provided on the entire surface of the pillar 48, the antenna unit 15 is, for example, the measurement device 100A and the measurement sensor. It is enlarged compared with 102. Thereby, the speed at which the antigen P is adsorbed to the reaction film 20 can be increased, and the measurement speed and sensitivity of the measurement device 100E and the measurement sensor of the fourth embodiment can be increased.

[Configuration of measurement sensor]
Although not shown, the measurement sensor of the fourth embodiment uses a light source similar to the light source 3 of the measurement sensor 102 of the first embodiment on the back surface 5a of the semiconductor substrate 5 of the measurement device 100E shown in FIGS. It is what it has.

[Principle of measurement sensor]
Regarding the principle of the measurement sensor of the fourth embodiment, the light L is irradiated from the light source provided on the back surface 5a of the semiconductor substrate 5 and directly incident on the semiconductor substrate 5 from the back surface 5a. This is the same as the device 100E.

[Modification]
Although the fourth embodiment to which the present invention is applied has been described in detail above, the measurement device 100E and the measurement sensor according to the fourth embodiment are within the scope of the present invention described in the claims. Various modifications and changes similar to those of the measurement device 100A and the measurement sensor 102 of the first embodiment and the measurement device 100B and the measurement sensor of the second embodiment are possible.

  For example, the pillar 48 is not limited to a cylindrical shape as long as it can resonate electromagnetic waves along the height direction, and may be a polygonal column or other shapes. Further, as illustrated in FIGS. 9 and 10, a plurality of pillars 48 need not be regularly arranged in a plan view, and a single pillar 48 may be provided, and a plurality of pillars 48 may be irregularly arranged in a plan view. May be.

  The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific embodiments, and various modifications are possible within the scope of the gist of the present invention described in the claims. Deformation / change is possible.

  Next, an example for confirming the effectiveness of the measurement device according to the present invention will be described. In addition, the structure and effect of the measurement device according to the present invention are not limited to the following examples.

First, an Au diffraction grating was prototyped, and it was experimentally confirmed that SPR resonance actually occurred in the Au diffraction grating. The pitch of the Au diffraction grating used is 3.4 μm, near infrared light having a wavelength of 1100 nm is irradiated from the laser source, and the Au diffraction grating is irradiated through the polarizer into a TM wave. The rotation angle was measured from 0 ° to 30 °, with the angle perpendicular to the surface of the Au diffraction grating being 0 °. The Au diffraction grating was provided with a current extraction wiring, and the generated current was measured by light irradiation therefrom. As a result, a large current flowed in the negative direction at an incident angle of 22.0 °. This angle substantially coincides with the angle θ _S = 21.4 ° obtained from the above-described equation (4) and the like. From this, it can be interpreted that the quantum efficiency of the internal photoelectric effect is increased and a large current is generated because light absorption is promoted by SPR. From the above, it was concluded that SPR was generated by the prototyped Au diffraction grating, and that SPR could be measured as a current by the Schottky barrier.

  Next, a simulation was performed to verify whether the prototype Au diffraction grating can excite SPR by backside illumination. For the simulation, COMSOL, which is a Finite Element Method (FEM) software, was used. In this simulation, the arrangement of irradiating light from the Si side is “back arrangement” so that the incident optical path does not interfere with the sample.

  An outline of the created simulation is shown in FIG. In this simulation, a structure in which an Au diffraction lattice exists on Si is assumed. As shown in FIG. 11, the pitch of the diffraction grating was 1200 nm, and the width of the Au diffraction grating was 950 nm. Unlike the above-mentioned trial manufacture and experiment, the diffraction grating was not connected with Au, and Si was exposed between adjacent Au (resonance part in 1st embodiment). This structure was set to irradiate light from the Si side. The polarized light was TM polarized light. Further, assuming that the SPR is excited by a change in the wavelength of the incident light, the wavelength of the light incident on the model shown in FIG. 11 was also changed in the simulation. Then, in order to verify the effectiveness as an SPR sensor, the refractive index of the dielectric that is in contact with the Au diffraction grating was calculated under two conditions of 1.0 and 1.1.

  When the width of the Au diffraction grating is 950 nm as described above (the solid line of “W950 nm” in FIG. 12) and the case where it is 900 nm as another pattern (the dashed line of “W900 nm” in FIG. 12), As shown in FIG. 12, when the width (W) is reduced, the light absorption peak is shifted to the short wavelength side.

  FIG. 13 shows the correlation between the change in response to the change in the wavelength of incident light on the model shown in FIG. 11 and the model size. The case where the width of the Au diffraction grating is 950 nm corresponds to the case where the width D of the Au diffraction grating in the graph shown in FIG. 13 (corresponding to the width d shown in FIG. 1) = 950 nm. On the other hand, the case where the width of the Au diffraction grating is 900 nm corresponds to the case where the width of the Au diffraction grating D in the graph shown in FIG. 13 is 900 nm.

FIG. 14 shows a plot of the electric field strength at 1.94 × 10 ¹⁴ Hz, which is the resonance point of the model shown in FIG. Similar to the result of a similar previous example shown in FIG. 15 (Ali Sobhani, et al., “Narrowband photodetection in the near-infrared with a plasmon-induced hot electron device,” Nature Communications, vol. 4, 1643, 2013.) However, there is a difference in the field state of the Air part.

FIG. 16 shows the light absorption characteristics of the model shown in FIG. 11, and FIG. 17 shows a plot of the electric field strength at 2.6 × 10 ¹⁴ Hz, which is a resonance point different from the resonance point plotted in FIG. Since the peak (P1) shown in FIG. 16 is not sharp, it is estimated that a plurality of peaks appear adjacent to each other. If various dimensions of the model shown in FIG. 11 are changed, it is assumed that the peak shape and position change. In addition, the arrangement in which light is incident from the lower port in FIG. 17 is a rear arrangement, which is similar to the configuration of the measurement device according to the present invention. In FIG. 17, the spectra are different because the frequency of incident light is the same, but the light is incident on the interface through a high refractive index, so the momentum is high.

Furthermore, a simulation was performed on the behavior when the refractive index of the dielectric (Air) was changed. FIG. 19 shows a plot of the electric field strength at a resonance point of 2.6 × 10 ¹⁴ Hz when the refractive index of the dielectric (Air) is 1.0. FIG. 20 shows a plot of the electric field strength at a resonance point of 2.6 × 10 ¹⁴ Hz when the refractive index of the dielectric (Air) is 1.1. FIG. 21 shows a plot of the electric field strength at the resonance point: 1.95 × 10 ¹⁴ Hz when the refractive index of the dielectric (Air) is 1.1. FIG. 18 shows the light absorption characteristics of the model of FIG. 11 under these conditions. As shown in FIG. 18, it is presumed that the change is large in the mode resonance strongly localized at the Air / Au interface.

  Comprehensively considering the above simulation results, it was confirmed that the structure similar to the model shown in FIG. 11 can be used as a back-illuminated SPR sensor.

100A, 100B, 100C, 100D, 100E Measuring device 102 Measuring sensor

Claims (15)

A semiconductor substrate capable of transmitting light of a predetermined wavelength;
A metal layer that is laminated on the surface of the semiconductor substrate, forms a Schottky barrier at the interface with the semiconductor substrate, and has an antenna portion that causes surface plasmon resonance when irradiated with light of the predetermined wavelength;
A reaction layer formed on the surface of the metal layer and configured to be capable of reacting with a specific detection substance;
A measuring device characterized by comprising:   The measuring device according to claim 1, comprising a surface opposite to the surface of the semiconductor substrate and an electrode portion electrically connected to the metal layer.   The said metal layer is provided with the resonance part formed along the surface of the said semiconductor substrate, and the current collection part connected to the said some resonance part, The Claim 1 or 2 characterized by the above-mentioned. Measuring device. The predetermined wavelength is not less than 1 μm and not more than 10 μm,
The semiconductor substrate is made of n-type silicon;
The measuring device according to claim 3, wherein the resonance portion has a width of 0.5 μm or more and 5 μm or less. A diffraction grating is formed on the surface of the semiconductor substrate,
The measurement device according to claim 1, wherein the metal layer and the antenna unit are provided on a surface of the diffraction grating. A diffraction grating is formed on the surface of the metal layer,
The measurement device according to claim 1, wherein the antenna unit is provided on a surface side of the metal layer. At least one of a fine concave portion and a convex portion is formed on the surface of the antenna portion,
The width of the said recessed part and the said convex part is 1/1000 or more and 1/10 or less of the said predetermined wavelength, The measuring device as described in any one of Claim 1 to 6 characterized by the above-mentioned. Pillars are formed on the surface of the semiconductor substrate,
The measuring device according to claim 1, wherein the metal layer and the antenna unit are provided on a surface of the pillar. A light source that emits light of a predetermined wavelength;
A semiconductor substrate stacked on the light source and capable of transmitting light of the predetermined wavelength;
An antenna unit that is stacked on a surface of the semiconductor substrate opposite to the light source, forms a Schottky barrier at the interface with the semiconductor substrate, and causes surface plasmon resonance when irradiated with light emitted from the light source A metal layer having
A reaction layer formed on the surface of the metal layer and configured to be capable of reacting with a specific detection substance;
An electrode portion electrically connected to the light source side surface of the semiconductor substrate and the metal layer;
A measurement sensor comprising:   The measurement according to claim 9, wherein the metal layer includes a resonance part formed along a surface of the semiconductor substrate, and a current collecting part connected to the plurality of resonance parts. Sensor. The predetermined wavelength is not less than 1 μm and not more than 10 μm,
The semiconductor substrate is made of n-type silicon;
The measurement sensor according to claim 10, wherein a width of the resonance part is 0.5 μm or more and 5 μm or less. A diffraction grating is formed on the surface of the semiconductor substrate,
The sensor for measurement according to claim 9, wherein the metal layer and the antenna unit are provided on a surface of the diffraction grating. A diffraction grating is formed on the surface of the metal layer,
The measurement sensor according to claim 9, wherein the antenna unit is provided on a surface side of the metal layer. At least one of a fine concave portion and a convex portion is formed on the surface of the antenna portion,
The width of the said recessed part and the said convex part is 1/1000 or more and 1/10 or less of the said predetermined wavelength, The measurement sensor as described in any one of Claims 9-13 characterized by the above-mentioned. Pillars are formed on the surface of the semiconductor substrate,
The measurement sensor according to claim 9, wherein the metal layer and the antenna unit are provided on a surface of the pillar.