Light-emitting element, light detection module, method for manufacturing light-emitting element, and scanning electron microscope

Abstract

The present invention addresses the problem of providing a light-emitting element, a light detection module, a method for manufacturing a light-emitting element, and a scanning electron microscope using the light-emitting element, whereby crosstalk can be reduced and use can be expanded. This light-emitting element (1) is provided with: an optical fiber plate substrate (2) that is transparent to fluorescence; and a light emitting layer (3) made of a nitride semiconductor layer having a quantum well structure. In this light-emitting element (1), an optical fiber plate substrate (2) and a light-emitting layer (3) are directly bonded.

Description

[0001] This application is filed on November 25, 2021 、Application No. 202180078066.0 、The name of the invention is Luminescence Element, light detection module, method for manufacturing light emitting element, and scanning electron microscope Divisional application. Technical Field

[0002] The present disclosure relates to a light emitting element, a light detection module, a method for manufacturing the light emitting element, and a scanning electron microscope. Background Art

[0003] As a current light-emitting element, there is a light-emitting body described in Patent Document 1, for example. This current light-emitting body is a light-emitting body that converts incident electrons into fluorescence. The light-emitting body comprises: a substrate transparent to fluorescence; and a nitride semiconductor layer formed on one side of the substrate, having a quantum well structure and a buffer layer that generate fluorescence by the incidence of electrons. On the nitride semiconductor layer, there is provided: a cap layer composed of a material having a band gap energy greater than that of the constituent material of the nitride semiconductor layer.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent No. 4365255 Summary of the invention

[0007] Problems to be solved by the invention

[0008] In current light-emitting elements, when a nitride semiconductor layer is formed by crystal growth, a sapphire substrate or a GaN substrate is mainly used (for example, see the above-mentioned Patent Document 1). These substrates are single crystals. Therefore, there is a problem that a part of the light from the light-emitting layer diffuses using the substrate and the buffer layer as a waveguide during the period from when the light is incident on the substrate and the buffer layer to when the light is taken out into the atmosphere or vacuum, and the diffused component may become a major cause of crosstalk.

[0009] In addition, in the current light-emitting element, when a multi-channel light detection module or imaging unit is constructed by combining with a multi-channel light detector or image sensor, lens coupling must be performed. Therefore, there are the following problems: the miniaturization of the detection module or imaging unit is difficult and is easily limited by its use. In addition, in lens coupling, the efficiency of transmitting light from the light-emitting layer to the light detection module or imaging unit is sought to be improved.

[0010] The present disclosure is made to solve the above-mentioned problems, and its purpose is to provide a light-emitting element, a light detection module, a method for manufacturing a light-emitting element, and a scanning electron microscope using the same, which can reduce crosstalk and expand applications.

[0011] Means used to solve problems

[0012] A light emitting element according to one aspect of the present disclosure includes: an optical fiber sheet substrate having transparency to fluorescence; and a light emitting layer composed of a nitride semiconductor layer having a quantum well structure, wherein the optical fiber sheet substrate and the light emitting layer are directly bonded.

[0013] In this light-emitting element, the optical fiber board substrate and the light-emitting layer are directly bonded. In this light-emitting element, unlike the current structure in which the light-emitting layer is provided on the sapphire substrate with the buffer layer between them, it is possible to avoid a part of the light incident on the light-emitting element from diffusing using the sapphire substrate and the buffer layer as waveguides, thereby reducing crosstalk. By using an optical fiber board substrate instead of a sapphire substrate, the collection efficiency of the fluorescence generated in the light-emitting layer can be improved. In addition, it is possible to avoid the need for lens coupling when constructing a light detection module, thereby expanding the application.

[0014] The optical fiber sheet substrate and the light emitting layer may be bonded by thermocompression bonding. Thus, the optical fiber sheet substrate and the light emitting layer can be bonded directly and appropriately without using an adhesive.

[0015] Alternatively, the optical fiber board substrate and the light emitting layer may be bonded by bonding at room temperature. Thus, the optical fiber board substrate and the light emitting layer can be bonded directly and appropriately without using an adhesive. Furthermore, bonding at room temperature can also suppress deformation caused by heat from occurring in the optical fiber board substrate.

[0016] Alternatively, the constituent elements of the light emitting layer may be diffused into the optical fiber substrate. In this case, the diffusion of the constituent elements of the light emitting layer into the optical fiber substrate can sufficiently increase the bonding strength between the optical fiber substrate and the light emitting layer.

[0017] Alternatively, the light-emitting layer may have a stacked structure in which GaN layers and InGaN layers are alternately stacked. In this case, fluorescence can be efficiently generated in the light-emitting layer. In addition, the stacked structure is directly bonded to the optical fiber board substrate, so the generated fluorescence can be efficiently taken out to the optical fiber board substrate side.

[0018] Alternatively, a metal layer may be provided on the surface of the light-emitting layer opposite to the bonding surface between the optical fiber board substrate and the light-emitting layer. This can prevent the light-emitting layer from being charged when electrons or the like are incident on it. In addition, the generated fluorescence can be efficiently extracted to the optical fiber board substrate side by reflecting the light at the metal layer.

[0019] Alternatively, at the interface between the optical fiber substrate and the light-emitting layer, an intermediate layer having a refractive index with respect to fluorescence between the optical fiber substrate and the light-emitting layer may be provided on at least one of the optical fiber substrate and the light-emitting layer. In this case, by adjusting the refractive index of the intermediate layer, the intermediate layer can function as a functional layer such as an anti-reflection film at the interface between the optical fiber substrate and the light-emitting layer.

[0020] Alternatively, the intermediate layer may be formed by a SiN layer, a Ta 3 O 5 Layer, HfO 2 Layers or their combinations are formed. Thus, the intermediate layer can function as a reflection prevention film. In addition, the design of a multilayer film containing other high refractive index materials also becomes easy.

[0021] A light detection module according to one aspect of the present disclosure includes the above-described light emitting element and a light detector disposed on the optical fiber board substrate side relative to the light emitting element.

[0022] In the light-emitting element constituting this light detection module, the optical fiber board substrate and the light-emitting layer are directly bonded. Therefore, unlike the current structure in which the light-emitting layer is provided on the sapphire substrate via the buffer layer, it is possible to avoid a portion of the light incident on the light-emitting element from diffusing using the sapphire substrate and the buffer layer as waveguides, thereby reducing crosstalk. By using an optical fiber board substrate instead of a sapphire substrate, the collection efficiency of the fluorescence generated in the light-emitting layer can be improved. In addition, it is possible to avoid the need for lens coupling when constructing the light detection module, thereby expanding the application.

[0023] The photodetector may be formed by a solid detection element or an electron tube element. Thus, the photodetection module can be used for various purposes.

[0024] The manufacturing method of the light-emitting element of one aspect of the present disclosure comprises: a light-emitting layer forming step, in which a buffer layer and a light-emitting layer composed of a nitride semiconductor layer having a quantum well structure are crystal-grown on an auxiliary substrate; and a bonding step, in which a fiber optic plate substrate having transparency to fluorescence is directly bonded to the light-emitting layer on the auxiliary substrate to form a bonded body; and a removal step, in which the auxiliary substrate and the buffer layer are removed from the bonded body.

[0025] According to the manufacturing method of this light-emitting element, a light-emitting element in which a fiber plate substrate and a light-emitting layer are directly bonded can be easily obtained. In the obtained light-emitting element, unlike the current structure in which a light-emitting layer is provided on a sapphire substrate with a buffer layer therebetween, it is possible to avoid a portion of the light incident on the light-emitting element from diffusing using the sapphire substrate and the buffer layer as a waveguide, thereby reducing crosstalk. By using a fiber plate substrate instead of a sapphire substrate, the collection efficiency of the fluorescence generated in the light-emitting layer can be improved. In addition, it is possible to avoid the need for lens coupling when constructing a light detection module, thereby expanding the application.

[0026] Alternatively, the light-emitting layer may have a stacked structure in which GaN layers and InGaN layers are alternately stacked, and the buffer layer may be formed by a GaN layer. Thus, the light-emitting layer can be appropriately crystallized and grown on the auxiliary substrate. In the obtained light-emitting element, fluorescence can be efficiently generated in the light-emitting layer. In addition, the stacked structure is directly bonded to the optical fiber board substrate, so the generated fluorescence can be efficiently taken out to the optical fiber board substrate side.

[0027] Alternatively, after the removal step, there may be a metal layer forming step of forming a metal layer on the surface of the light emitting layer opposite to the bonding surface of the optical fiber board substrate and the light emitting layer. Thus, in the obtained light emitting element, it is possible to prevent the light emitting layer from being charged when electrons or the like are incident on it. In addition, by reflecting light at the metal layer, the generated fluorescence can be efficiently extracted to the optical fiber board substrate side.

[0028] Alternatively, between the light-emitting layer forming step and the bonding step, an intermediate layer forming step is provided, wherein an intermediate layer having a refractive index for fluorescence between the refractive index of the optical fiber substrate and the light-emitting layer is formed on at least one of the optical fiber substrate and the light-emitting layer. In this case, by adjusting the refractive index of the intermediate layer, the intermediate layer can function as a functional layer such as an anti-reflection film at the bonding surface between the optical fiber substrate and the light-emitting layer.

[0029] Alternatively, the intermediate layer may be formed by a SiN layer, a Ta 3 O 5 Layer, HfO 2 Layers or their combinations are formed. Thus, the intermediate layer can function as a reflection prevention film. In addition, the design of a multilayer film containing other high refractive index materials also becomes easy.

[0030] A scanning electron microscope according to one aspect of the present disclosure comprises: an electron beam source that emits primary electron beams toward a sample; the light emitting element that generates fluorescence by the incidence of secondary electron beams generated in the sample due to irradiation with the primary electron beams; and a detection optical system that detects the fluorescence generated by the light emitting element.

[0031] In the light-emitting element constituting this scanning electron microscope, the optical fiber plate substrate and the light-emitting layer are directly bonded. Therefore, unlike the current structure in which the light-emitting layer is provided on the sapphire substrate via the buffer layer, it is possible to prevent a portion of the light incident on the light-emitting element from diffusing using the sapphire substrate and the buffer layer as waveguides, thereby reducing crosstalk. By using the optical fiber plate substrate instead of the sapphire substrate, the collection efficiency of the fluorescence generated in the light-emitting layer can be improved.

[0032] Effects of the Invention

[0033] According to the present disclosure, crosstalk can be reduced and applications can be expanded. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 Schematic cross-sectional view showing one embodiment of a light emitting element.

[0035] Figure 2 is a schematic cross-sectional view showing the structure of a light-emitting layer.

[0036] Figure 3 In the figure, (a) is an enlarged photograph of the vicinity of the bonding surface between the core glass of the optical fiber board substrate and the light-emitting layer, and (b) is an enlarged photograph of the vicinity of the bonding surface between the clad glass of the optical fiber board substrate and the light-emitting layer.

[0037] Figure 4 In the figure, (a) is the component analysis result near the joint surface between the core glass of the optical fiber board substrate and the light-emitting layer, and (b) is the component analysis result near the joint surface between the cladding glass of the optical fiber board substrate and the light-emitting layer.

[0038] Figure 5 This is a flowchart showing an example of a manufacturing process of a light emitting element.

[0039] Figure 6 In the figure, (a) is a schematic cross-sectional view showing a light emitting layer forming step, and (b) is a schematic cross-sectional view showing a bonding step.

[0040] Figure 7 In the drawings, (a) and (b) are schematic cross-sectional views showing the removal process.

[0041] Figure 8 It is a schematic cross-sectional view showing the metal layer forming process.

[0042] Fig. 9 In the figure, (a) is a diagram showing the spot shape of fluorescence in a comparative example, and (b) is a diagram showing the spot shape of fluorescence in an example.

[0043] Fig.10 It is a graph showing the brightness distribution of fluorescence in Examples and Comparative Examples.

[0044] Fig.11 In the drawings, (a) to (c) are schematic diagrams showing configuration examples of a light detection module using a light emitting element.

[0045] Fig.12 It is a schematic diagram showing a structural example of a scanning electron microscope.

[0046] Fig.13 It is a schematic cross-sectional view showing a modification example of the light emitting element.

[0047] Fig.14It is a flowchart showing an example of a manufacturing process of the light emitting element of a modification.

[0048] Fig.15 It is a schematic cross-sectional view showing the intermediate layer forming process. DETAILED DESCRIPTION

[0049] Hereinafter, preferred embodiments of a light emitting element, a light detection module, a method for manufacturing a light emitting element, and a scanning electron microscope according to one aspect of the present disclosure will be described in detail with reference to the accompanying drawings.

[0050] [Structural example of light emitting element]

[0051] Figure 1 FIG. 1 is a schematic cross-sectional view showing one embodiment of a light emitting element. The light emitting element 1 is an element that generates fluorescence by the incidence of electrons or the like. Figure 1 As shown, the light emitting element 1 is configured to include a fiber optic plate substrate 2 , a light emitting layer 3 , and a metal layer 4 .

[0052] The optical fiber board substrate 2 is a substrate having the function of transmitting light incident from the incident surface 2a to the exit surface 2b. The optical fiber board substrate 2 is transparent to the light (fluorescence) generated in the light emitting layer 3. The optical fiber board substrate 2 is, for example, configured to include a plurality of core glasses, a cladding glass covering the core glasses, and an absorber glass arranged between the plurality of core glasses. The core glass and the cladding glass are integrated. The core glass is in a fiber shape and extends from the incident surface 2a of the optical fiber board substrate 2 to the exit surface 2b. The diameter of the core glass is, for example, about 0.001 to 0.05 mm. The cross-sectional shape of the core glass is, for example, circular.

[0053] The core glass may contain a mesh-forming oxide that forms the mesh of the glass, a mesh-modifying oxide that melts with the mesh-forming oxide and affects the properties of the glass, and an intermediate oxide having properties intermediate between the mesh-forming oxide and the mesh-modifying oxide. Examples of the mesh-forming oxide include B 2 O 3 、SiO 2 、ZrO 2 As mesh-modifying oxides, WO 3 , Gd 2 O 3 ,La 2 O 3 , Nb 2 O 5 As the intermediate oxide, TiO 2 、ZrO 2 , ZnO, etc.

[0054] The cladding glass is arranged to bury the core glass and cover the respective outer peripheries of the core glass. The cladding glass extends from the incident surface 2a of the optical fiber board substrate 2 to the exit surface 2b. The cladding glass, like the core glass, may contain: a mesh-forming oxide that forms the mesh of the glass, a mesh-modifying oxide that melts with the mesh-forming oxide and affects the properties of the glass, and an intermediate oxide having properties intermediate between the mesh-forming oxide and the mesh-modifying oxide. The refractive index of the cladding glass is smaller than the refractive index of the core glass.

[0055] The light absorbing glass is in the form of a fiber thinner than the core glass, and extends from the incident surface 2a to the exit surface 2b of the optical fiber board substrate 2. The light absorbing glass has the property of absorbing light (stray light) leaking from the core glass and the cladding glass. The light absorbing glass can also be composed of a glass composition. The glass composition is SiO 2 Main component, may also contain Fe 2 O 3 wait.

[0056] The light emitting layer 3 is a layer composed of a nitride semiconductor layer having a quantum well structure. The light emitting layer 3 has a surface 3a facing the optical fiber board substrate 2 and another surface 3b located on the opposite side of the surface 3a. The quantum well structure here includes a quantum wire structure and a quantum dot structure in addition to a general quantum well structure. In addition, the nitride semiconductor is a compound containing at least one of Ga, In, and Al as a group III element, and mainly containing N as a group V element.

[0057] In this embodiment, if Figure 2 As shown, the light emitting layer 3 has a stacked structure in which GaN layers 6 and InGaN layers 7 are alternately stacked. The light emitting layer 3 does not have an InGaN layer as a buffer layer. x Ga 1-x N (0≦x≦1) layer or GaN layer, the GaN layer 6 constituting the outermost layer of the quantum well structure constitutes one side 3a and the other side 3b. If electrons etc. are incident on the light-emitting layer 3, pairs of electrons and holes are formed in the quantum well structure, and the pairs of electrons and holes generate fluorescence in the process of recombination in the quantum well structure. At least a part of the fluorescence generated in the light-emitting layer 3 is incident on the incident surface 2a of the optical fiber board substrate 2, guided by the core glass and emitted from the exit surface 2b.

[0058] The metal layer 4 is a layer having a function of preventing the light emitting layer 3 from being charged when electrons or the like are incident on it. In addition, the metal layer 4 has a function of reflecting the fluorescence generated in the light emitting layer 3 and transmitting the fluorescence to the optical fiber board substrate 2 side with good efficiency. The metal layer 4 is provided on the surface opposite to the bonding surface R between the optical fiber board substrate 2 and the light emitting layer 3, that is, the other surface 3b of the light emitting layer 3. The metal layer 4 is provided over the entire other surface 3b of the light emitting layer 3 by vapor deposition of a metal such as Al, for example, with a thickness sufficiently smaller than that of the light emitting layer 3.

[0059] In the light emitting element 1, the optical fiber substrate 2 and the light emitting layer 3 are directly bonded to form a bonding surface R. In this embodiment, the incident surface 2a of the optical fiber substrate 2 and the surface 3a of the light emitting layer 3 are bonded by thermocompression bonding or room temperature bonding without the intermediary of adhesives. Figure 3 (a) and Figure 3 (b) is an enlarged photograph of the vicinity of the bonding surface of the optical fiber sheet substrate and the light emitting layer bonded by thermocompression bonding. Figure 3 (a) is a scanning transmission electron microscope analysis of the joint surface between the core glass and the light-emitting layer of the optical fiber board substrate. Figure 3 (b) is a scanning transmission electron microscope analysis of the junction surface between the cladding glass and the light-emitting layer of the optical fiber board substrate. Figure 3 (a) and Figure 3 The results shown in (b) confirm that both the core glass and the cladding glass of the optical fiber sheet substrate are integrated with the light emitting layer by thermocompression bonding and are firmly bonded without the intermediary of an adhesive or the like.

[0060] In the light emitting element 1, the incident surface 2a of the optical fiber substrate 2 and the one surface 3a of the light emitting layer 3 are thermally pressed together, so that the constituent elements of the light emitting layer 3 are diffused into the optical fiber substrate 2. Alternatively, the constituent elements of the optical fiber substrate 2 are diffused into the light emitting layer 3. Figure 4 (a) is the component analysis result near the joint surface between the core glass and the light-emitting layer of the optical fiber board substrate. Figure 4 (b) is the component analysis result near the joint surface of the cladding glass and the light-emitting layer of the optical fiber board substrate. In these figures, the horizontal axis represents distance and the vertical axis represents intensity. The distance of 50nm is equivalent to the joint surface of the core glass and the light-emitting layer of the optical fiber board substrate. The light-emitting layer is on the left side and the optical fiber board substrate is on the right side. The focused ion beam method was used to process the sample. As a component analysis device, an atomic resolution analysis electron microscope (product name: JEM-ARM200F DUAL-X) manufactured by JEOL Ltd. was used, and the acceleration voltage was set to 200kV.

[0061] Depend on Figure 4 The result shown in (a) shows that Ga contained in the light-emitting layer 3 diffuses into the core glass of the optical fiber board substrate 2. In addition, it can be seen that La contained in the core glass of the optical fiber board substrate 2 diffuses into the light-emitting layer 3. Figure 4The result shown in (b) shows that In or Ga contained in the light-emitting layer 3 diffuses into the cladding glass of the optical fiber substrate 2. In addition, it can be seen that Si contained in the cladding glass of the optical fiber substrate 2 diffuses into the light-emitting layer 3. By diffusing the constituent elements of the light-emitting layer 3 into the optical fiber substrate 2, or diffusing the constituent elements of the optical fiber substrate 2 into the light-emitting layer 3, the bonding strength between the optical fiber substrate 2 and the light-emitting layer 3 is sufficiently improved.

[0062] [Production Example of Light-Emitting Element]

[0063] Figure 5 As shown in the figure, the manufacturing process of the light emitting element 1 includes: a light emitting layer forming process (step S01), a bonding process (step S02), a removal process (step S03), and a metal layer forming process (step S04).

[0064] The light emitting layer forming process, such as Figure 6 As shown in (a), it is a process for crystallizing and growing a buffer layer 12 and a light-emitting layer 3 composed of a nitride semiconductor layer having a quantum well structure on an auxiliary substrate 11. The buffer layer 12 and the light-emitting layer 3 can be formed, for example, using a metal organic chemical vapor deposition (MOCVD) method. Here, the auxiliary substrate 11 is a sapphire substrate 13. The sapphire substrate 13 is introduced into the growth chamber of the MOCVD device, and heat-treated in a hydrogen atmosphere to purify the surface. Next, the substrate temperature is raised to about 1075°C and a GaN buffer layer 12 is formed on the sapphire substrate 13. After the buffer layer 12 is formed, the substrate temperature is lowered to about 800°C, and the GaN layer 6 and the InGaN layer 7 are alternately grown to obtain the light-emitting layer 3.

[0065] The bonding step is a step of directly bonding the optical fiber plate substrate 2 and the light emitting layer 3 on the auxiliary substrate 11 to form a bonded body K. Figure 6 As shown in (b), one side 3a of the light emitting layer 3 on the auxiliary substrate 11 and the incident surface 2a of the optical fiber board substrate 2 are made to face each other, and one side 3a of the light emitting layer 3 and the incident surface 2a of the optical fiber board substrate 2 are thermally pressed. The conditions for thermal pressing are, for example, a temperature of 100°C to 800°C and a pressure of 2kg / cm 2 ~40kg / cm 2 In the obtained bonded body K, the constituent elements of the light emitting layer 3 diffuse into the optical fiber board substrate 2, and the constituent elements of the optical fiber board substrate 2 diffuse into the light emitting layer 3, thereby achieving a strong bond between the optical fiber board substrate 2 and the light emitting layer 3.

[0066] The removal step is a step of removing the auxiliary substrate 11 and the buffer layer 12 from the bonded body K. The auxiliary substrate 11, that is, the sapphire substrate 13 can be removed by, for example, laser lift-off. Figure 7 As shown in (a), for example, a pulsed high-density UV laser is irradiated toward the sapphire substrate 13 to reach the GaN buffer layer 12. As a result, GaN is decomposed into Ga and N near the interface of the buffer layer 12, and the sapphire substrate 13 can be peeled off from the buffer layer 12.

[0067] After peeling off the sapphire substrate 13, Figure 7 As shown in (b), the buffer layer 12 is removed by etching. The buffer layer 12 of GaN is chemically stable, so from the viewpoint of ensuring the etching speed, dry etching is preferably used. As a method of dry etching, for example, reactive ion etching (RIE), reactive ion beam etching (RIBE), chemically assisted ion beam etching (CAIBE), electron cyclotron resonance etching (ECRE), etc. can be cited. In addition, as with the removal of the buffer layer 12, the removal of the sapphire substrate 13 can also be implemented by etching. Sapphire and GaN are chemically stable and are very hard materials, but they can also be processed by grinding and polishing. Therefore, as a method for removing the sapphire substrate 13 and the buffer layer 12 of GaN, processing by grinding and polishing can also be adopted.

[0068] The metal layer forming step is a step of forming the metal layer 4 on the other side 3b of the light emitting layer 3. Figure 8 As shown, Al is evaporated on the other side 3b of the light emitting layer 3 to form a metal layer 4. Thus, Figure 1 The light-emitting element 1 is shown.

[0069] [Effects]

[0070] As described above, in the light emitting element 1, the optical fiber board substrate 2 and the light emitting layer 3 are directly bonded. In this light emitting element 1, unlike the existing structure in which the light emitting layer 3 is provided on the sapphire substrate 13 via the buffer layer, it is possible to avoid a part of the light incident on the light emitting element 1 from diffusing using the sapphire substrate and the buffer layer as waveguides, thereby reducing crosstalk. By using the optical fiber board substrate 2 instead of the sapphire substrate, the collection efficiency of the fluorescence generated in the light emitting layer 3 can be improved. In addition, it is possible to avoid the need for lens coupling when constructing a light detection module, thereby expanding the application.

[0071] In the light emitting element 1, the optical fiber substrate 2 and the light emitting layer 3 are bonded by thermocompression bonding. Thus, the optical fiber substrate 2 and the light emitting layer 3 can be bonded directly and appropriately without using an adhesive. In addition, in the light emitting element 1, the constituent elements of the light emitting layer 3 diffuse into the optical fiber substrate 2, and the constituent elements of the optical fiber substrate 2 diffuse into the light emitting layer 3. By such diffusion of constituent elements, the bonding strength between the optical fiber substrate 2 and the light emitting layer 3 can be sufficiently improved.

[0072] In the light emitting element 1, the light emitting layer 3 has a stacked structure in which GaN layers 6 and InGaN layers 7 are alternately stacked. By having such a stacked structure, fluorescence can be efficiently generated in the light emitting layer 3. In addition, the stacked structure is directly bonded to the optical fiber board substrate 2, so the generated fluorescence can be efficiently taken out to the optical fiber board substrate 2 side. In the light emitting element 1, a metal layer 4 is provided on the other surface 3b of the light emitting layer 3. This metal layer 4 can prevent the electrons and the like from being charged when incident on the light emitting layer 3. In addition, by reflecting the light at the metal layer 4, the generated fluorescence can be efficiently taken out to the optical fiber board substrate 2 side.

[0073] Fig. 9 (a) is a diagram showing the spot shape of fluorescence in a comparative example, Fig. 9 (b) is a diagram showing the spot shape of fluorescence in the embodiment. Fig.10 Graph showing the brightness distribution of fluorescence in the examples and comparative examples. Figure 1 Similarly, the light emitting element 1 used a sample in which an optical fiber plate substrate and a light emitting layer were directly bonded, and the comparative example used a sample in which a light emitting layer was provided on a sapphire substrate via an InGan buffer layer and a GaN layer.

[0074] In the comparative sample, Fig. 9 (a) and Fig.10 As shown in FIG. 1 , the full width at half maximum of the fluorescence that penetrates the sapphire substrate and is taken out to the outside is about 50 μm. Fig. 9 (b) and Fig.10 As shown in FIG. 1 , the full width at half maximum of the fluorescence extracted from the optical fiber sheet substrate to the outside is about 42 μm. Therefore, it can be confirmed that in the example, the diffusion of the fluorescence generated in the light emitting layer is reduced, and the crosstalk suppression effect is exerted.

[0075] [Application examples of light-emitting elements]

[0076] The above-mentioned light emitting element 1 can construct various light detection modules 21 by configuring a light detector 22 on the side of the optical fiber board substrate 2, for example. The light detector 22 is formed by a solid detection element or an electron tube device. As solid detection elements, image sensors such as CCD or CMOS, photodiode arrays, avalanche photodiode arrays, avalanche photodiode arrays operating in Geiger mode, image intensifiers, etc. can be cited. As electron tube devices, photomultiplier tubes, streak tubes, etc. can be cited.

[0077] From the perspective of fully utilizing the performance of the light emitting element 1, the light detector 22 may be a multi-channel detector that can simultaneously detect the position of a large amount of light, or may be a detector having time resolution performance. Examples of detectors that can perform both position detection and time resolution include multi-anode photomultiplier tubes, streak cameras, gated ICCD cameras, gated ICMOS cameras, and the like.

[0078] Fig.11 In the light detection module 21A shown in (a), a light detector 22 is arranged on the rear side of the light emitting element 1. The light detector 22 has an optical fiber plate 23 as an input window. The light detection module 21A is arranged in a vacuum container M such as a vacuum chamber or a vacuum tube. The light detection module 21A can be applied to the detection optical system of a scanning electron microscope, for example. In the vacuum container M, a microchannel plate (not shown) can also be arranged on the front side of the light emitting element 1. In this case, the charged particles can be converted into electrons and multiplied by the microchannel plate, so that the image and time characteristics of the tiny charged particles can be obtained.

[0079] Fig.11 In the light detection module 21B shown in (b), a light detector 22 is arranged on the rear side of the light emitting element 1. The light detector 22 has an optical fiber plate 23 as an input window. In the light detection module 21B, the light emitting element 1 is arranged in a vacuum container M such as a vacuum chamber or a vacuum tube, and the light detector 22 is arranged outside the vacuum container M. An optical fiber plate 24 is also arranged between the light emitting element 1 and the light detector 22. The optical fiber plate 24 is optically coupled to the light emitting element 1 and the optical fiber plate 23 of the light detector 22, and is configured as a window material of the vacuum container M to maintain the vacuum airtightness of the vacuum container M. The light detection module 21B can be used, for example, in a time-of-flight mass spectrometer (TOF-MS) device to replace the current camera device. Fig.11 Similarly to the case (a), a microchannel plate (not shown) may be arranged in the vacuum container M at the front stage side of the light emitting element 1 .

[0080] Fig.11 In the light detection module 21C shown in (c), a light detector 22 is arranged on the rear side of the light emitting element 1. The light detector 22 has an optical fiber plate 23 as an input window. The light detection module 21C is arranged in the atmosphere, for example. The light detection module 21C, for example, can use the light detector 22 as a streak tube, and combine an X-ray source or a pinhole lens on the front side of the light emitting element 1, so as to be suitable for an X-ray streak camera. The light emitting element 1 can also emit light for other radiations, and can implement time-resolved observation of radiations.

[0081] Fig.12Schematic diagram showing a structural example of a scanning electron microscope. The scanning electron microscope 31 shown in the same figure is a multi-beam scanning electron microscope, which is configured to include an electron beam source 32 that can emit multiple primary electron beams e1, the above-mentioned light-emitting element 1, and a detection optical system 33. The electron beam source 32, the sample S, and the light-emitting element 1 are arranged in a vacuum chamber 34. The detection optical system 33 is composed of an optical fiber plate 35 that serves as a window material of the vacuum chamber 34 to keep the vacuum chamber 34 airtight, and a photodetector 36. The photodetector 36 is a multi-channel detector having an optical fiber plate 37 as an input window, and is arranged in the atmosphere.

[0082] The electron beam source 32 emits a plurality of primary electron beams e1 toward the sample S. The plurality of primary electron beams e1 are irradiated to the sample S in a state where the trajectories are changed from the emission axis via the beam splitter 38. The sample S is arranged on a platform 39, and the platform 39 is movable in a surface direction orthogonal to the incident axis of the plurality of primary electron beams e1. If the plurality of primary electron beams e1 emitted from the electron beam source 32 are irradiated to the sample S, a plurality of secondary electron beams e2 are emitted from the surface of the sample S. The plurality of secondary electron beams e2 emitted from the surface of the sample S change their trajectories toward the opposite side of the emission axis of the plurality of primary electron beams e1 via the beam splitter 38, and are incident on the light emitting element 1. In the light emitting element 1, fluorescence corresponding to the incident secondary electron beam e2 is generated. The fluorescence generated in the light emitting element 1 is guided to the optical fiber plate 37 and guided into the atmosphere, and is incident on the photodetector 36. In the photodetector 36, a detection signal corresponding to the received fluorescence is output. By synchronizing the position of the primary electron beam e1 on the surface of the sample S with the detection signal from the photodetector 36 , an image of the sample S can be obtained.

[0083] [Modifications]

[0084] The present disclosure is not limited to the above-mentioned embodiments. In the above-mentioned embodiments, as a means for achieving direct bonding between the optical fiber board substrate 2 and the light-emitting layer 3, thermal compression bonding is exemplified, but the optical fiber board substrate 2 and the light-emitting layer 3 can also be directly bonded by normal temperature bonding. In normal temperature bonding, the incident surface 2a of the optical fiber board substrate 2 and one surface 3a of the light-emitting layer 3 are polished, and the polished surfaces are brought into contact with each other. Even by such normal temperature bonding, the optical fiber board substrate 2 and the light-emitting layer 3 can be properly directly bonded without using an adhesive. In addition, by normal temperature bonding, deformation caused by heat can also be suppressed from occurring in the optical fiber board substrate 2. In addition, when performing normal temperature bonding, a GaN substrate is preferably used as the auxiliary substrate 11. By using a GaN substrate as the auxiliary substrate 11, warping of the substrate can be relatively suppressed, and the yield of normal temperature bonding can be improved.

[0085] like Fig.13As shown, at the joint surface R between the optical fiber substrate 2 and the light emitting layer 3, an intermediate layer 41 having a refractive index for fluorescence between the optical fiber substrate 2 and the light emitting layer 3 may be provided on at least one of the optical fiber substrate 2 and the light emitting layer 3. The intermediate layer 41 may be formed by, for example, a SiN layer, a Ta 3 O 5 Layer, HfO 2 In this case, by adjusting the refractive index of the intermediate layer 41, the intermediate layer 41 can function as a functional layer such as an anti-reflection film at the bonding surface R between the optical fiber board substrate 2 and the light-emitting layer 3. In addition, the design of a multilayer film containing other high refractive index materials also becomes easy.

[0086] The intermediate layer 41 may be a component of the optical fiber board substrate 2, a component of the light emitting layer 3, or a component of both the optical fiber board substrate 2 and the light emitting layer 3. When the intermediate layer 41 is a component of the optical fiber board substrate 2, the incident surface 2a of the optical fiber board substrate 2 is constituted by the intermediate layer 41. When the intermediate layer 41 is a component of the light emitting layer 3, one surface 3a of the optical fiber board substrate 2 is constituted by the intermediate layer 41. Fig.13 In this example, the intermediate layer 41 is shown as a constituent element of the light-emitting layer 3 .

[0087] Fig.14 1 is a flowchart showing an example of a manufacturing process of a light emitting element in which an intermediate layer is formed. As shown in the figure, the manufacturing process of the light emitting element 1 in this case includes an intermediate layer forming process (step S05) between the light emitting layer forming process and the bonding process. The intermediate layer forming process is a process of forming an intermediate layer 41 on at least one of the optical fiber board substrate 2 and the light emitting layer 3. Fig.15 In the example of , in the intermediate layer forming step, the intermediate layer 41 is formed on the light emitting layer 3 side, and then one side 3a of the light emitting layer 3 composed of the intermediate layer 41 is thermally pressed to the incident surface 2a of the optical fiber board substrate 2. In the intermediate layer forming step, the intermediate layer 41 may be formed on the optical fiber board substrate 2 side. In the case where the intermediate layer 41 is composed of multiple layers, a part of the layers may be formed on the light emitting layer 3 side, and the remaining layers may be formed on the optical fiber board substrate 2 side.

[0088] Explanation of symbols

[0089] 1…light emitting element, 2…optical fiber board substrate, 3…light emitting layer, 4…metal layer, 6…GaN layer (nitride semiconductor layer), 7…InGaN layer (nitride semiconductor layer), 11…auxiliary substrate, 12…buffer layer, 13…sapphire substrate (auxiliary substrate), 21 (21A to 21C)…light detection module, 22…light detector, 31…scanning electron microscope, 32…electron beam source, e1…primary electron beam, e2…secondary electron beam, 33…detection optical system, 41…intermediate layer, R…joining surface.

Claims

1. A light emitting element, comprising: A fiber optic sheet substrate that is transparent to fluorescence; and A light-emitting layer composed of a nitride semiconductor layer having a quantum well structure, The optical fiber sheet substrate and the light emitting layer are directly bonded by thermocompression bonding.

2. The light-emitting element according to claim 1, wherein The light emitting layer is formed by crystal growth.

3. The light-emitting element according to claim 1 or 2, wherein: The conditions for thermal compression bonding are temperature 100℃~800℃, pressure 2kg / cm 2 ~40kg / cm 2 .

4. The light-emitting element according to any one of claims 1 to 3, wherein The constituent elements of the light emitting layer are diffused into the optical fiber board substrate.

5. The light-emitting element according to any one of claims 1 to 4, wherein The light emitting layer has a stacked structure in which GaN layers and InGaN layers are alternately stacked.

6. The light-emitting element according to any one of claims 1 to 5, wherein The light emitting layer is provided with a metal layer on a surface opposite to a bonding surface between the optical fiber sheet substrate and the light emitting layer.

7. The light-emitting element according to any one of claims 1 to 6, wherein An intermediate layer having a refractive index for the fluorescence between that of the optical fiber substrate and the light emitting layer is provided on at least one of the optical fiber substrate and the light emitting layer.

8. The light-emitting element according to claim 7, wherein The intermediate layer is formed by a SiN layer, a Ta3O5 layer, a HfO2 layer or a combination thereof.

9. A light detection module, comprising: The light emitting element according to any one of claims 1 to 8; and The photodetector is arranged on the optical fiber board substrate side relative to the light emitting element.

10. The optical detection module according to claim 9, wherein: The photodetector is formed by a solid detection element or an electron tube element.

11. A method for manufacturing a light emitting element, comprising: a light-emitting layer forming step of crystal-growing a buffer layer and a light-emitting layer composed of a nitride semiconductor layer having a quantum well structure on an auxiliary substrate; a bonding step of directly bonding the optical fiber plate substrate having transparency to fluorescence and the light-emitting layer on the auxiliary substrate by thermocompression bonding to form a bonded body; and The removing step is to remove the auxiliary substrate and the buffer layer from the bonded body.

12. The method for manufacturing a light emitting element according to claim 11, wherein: The light emitting layer has a stacked structure in which GaN layers and InGaN layers are alternately stacked. The buffer layer is formed of a GaN layer.

13. The method for manufacturing a light emitting element according to claim 11 or 12, wherein: In the bonding process, the conditions for the thermal compression bonding are a temperature of 100°C to 800°C and a pressure of 2 kg / cm 2 ~40kg / cm 2 .

14. The method for manufacturing a light-emitting element according to any one of claims 11 to 13, wherein: After the removing step, a metal layer forming step is provided to form a metal layer on a surface of the light emitting layer opposite to a bonding surface between the optical fiber sheet substrate and the light emitting layer.

15. The method for manufacturing a light emitting element according to any one of claims 11 to 14, wherein: Between the light emitting layer forming step and the bonding step, there is provided an intermediate layer forming step of forming an intermediate layer having a refractive index for the fluorescence between that of the light emitting layer and that of the optical fiber substrate.

16. The method for manufacturing a light emitting element according to claim 15, wherein: The intermediate layer is formed by a SiN layer, a Ta3O5 layer, a HfO2 layer or a combination thereof.

17. A scanning electron microscope comprising: An electron beam source emits a primary electron beam toward the sample; The light emitting element according to any one of claims 1 to 8, wherein fluorescence is generated by the incidence of secondary electron beams generated by irradiation of the primary electron beams on the sample; and The detection optical system detects the fluorescence generated by the light emitting element.

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