JP2015109331A - Nitride semiconductor light-emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nitride semiconductor light-emitting device capable of interrupting the supply of drive current to a nitride semiconductor light-emitting element when the nitride semiconductor light-emitting element is exposed to the exterior.SOLUTION: The nitride semiconductor light-emitting device includes: a base 4; a nitride semiconductor light-emitting element 6 on the base 4; a transparent insulation plate 1 on the nitride semiconductor light-emitting element 6; a first electrode 3 and a second electrode 5 on the base 4; and a transparent conductive film 2 provided on the surface on the nitride semiconductor light-emitting element 6 side of the transparent insulation plate 1. The nitride semiconductor light-emitting element 6 has a first electrical connection part 61 and a second electrical connection part 62. The first electrode 3 is electrically connected to the first electrical connection part 61 through the transparent conductive film 2, and the second electrode 5 is electrically connected to the second electrical connection part 62.

Description

  The present invention relates to a nitride semiconductor light emitting device.

  AlN, GaN, and InN have band gap energies of about 6.0 eV, about 3.4 eV, and about 0.6 eV, respectively. Therefore, a nitride semiconductor light emitting device using such a mixed crystal as an active layer material can emit light having a wavelength from the ultraviolet region to the infrared region. Nitride semiconductor light-emitting elements are applied to various applications such as backlights for displays such as liquid crystal televisions or mobile phones or light sources for illumination.

  A light source for illumination using a nitride semiconductor light emitting device includes a nitride semiconductor light emitting device and a phosphor that uses light emitted from the nitride semiconductor light emitting device as excitation light and has a desired emission spectrum. A semiconductor light emitting device is common.

  Examples of nitride semiconductor light emitting devices used as illumination light sources include nitride semiconductor blue light emitting diode elements and YAG (yttrium, aluminum, garnet) phosphors or TAG (terbium, aluminum, garnet) phosphors. And a pseudo white light source having a combination of the above.

  The package structure of the nitride semiconductor light emitting device includes a form in which the nitride semiconductor light emitting element is encapsulated in the resin and a form in which the nitride semiconductor light emitting element is not included in the resin. When a high-luminance nitride semiconductor light-emitting diode element is used as the nitride semiconductor light-emitting element, sealing with a resin may not be possible due to restrictions such as heat dissipation or optical design. In addition, when an ultraviolet light emitting diode element is used as the nitride semiconductor light emitting element, it is difficult to use a resin as a sealing material from the viewpoint of deterioration of the resin due to ultraviolet irradiation.

  Further, for example, in Patent Document 1, an ultraviolet light-emitting diode element formed on a ceramic body is electrically connected to a first electrode and a second electrode formed on the ceramic body. An ultraviolet light emitting device package having a glass film on the top is disclosed.

JP 2012-227511 A

  In a light emitting device of a type such as the ultraviolet light emitting element package described in Patent Document 1, a type in which a first electrode and a second electrode provided on a pedestal are connected to a light emitting diode element with a metal wire is generally used. It is. There is also a type in which the first electrode and the second electrode provided on the pedestal by a flip chip method or the like and the light emitting diode element are electrically connected by solder or the like.

  Also, in the nitride semiconductor light emitting device for illumination light source, the emitted light from the nitride semiconductor light emitting element installed on the pedestal excites the phosphor in the phosphor plate, and only the fluorescence from the phosphor is used as illumination. There is a format in which not only the fluorescence from the phosphor in the phosphor plate but also a part of the emitted light from the nitride semiconductor light emitting element is used as illumination.

  The light emitted from the nitride semiconductor light-emitting element used in the nitride semiconductor light-emitting device for the illumination light source is ultraviolet light or high-intensity visible light, etc., and may cause eye damage if directly viewed by humans. Is very high and often harmful.

  Therefore, the intensity of the light emitted from the nitride semiconductor light emitting element used in the nitride semiconductor light emitting device for the illumination light source is absorbed by the phosphor while passing through the phosphor plate, and does not cause damage to human eyes. It is common to use a lens or the like that is optically designed so that it is attenuated to the extent that it does not enter human vision.

  Examples of the application of the nitride semiconductor light emitting device for illumination light source include general illumination, a light source for headlights such as automobiles, and a light source for projectors.

  However, in a conventional nitride semiconductor light emitting device for an illumination light source, the nitride semiconductor light emitting element may be exposed to the outside due to factors such as the phosphor plate being detached. Even when the nitride semiconductor light emitting device is exposed to the outside, a driving current is continuously applied to the nitride semiconductor light emitting device, and thus harmful light continues to be emitted from the nitride semiconductor light emitting device. Such a situation may occur not only during the manufacturing process of the nitride semiconductor light emitting device for the illumination light source but also during the actual use of the nitride semiconductor light emitting device for the illumination light source.

  In view of the above circumstances, in a later-described embodiment, a nitride semiconductor light-emitting device that can cut off the supply of drive current to the nitride semiconductor light-emitting element when the nitride semiconductor light-emitting element is exposed to the outside is provided. It is to provide.

  According to an embodiment of the present invention, a pedestal, a nitride semiconductor light emitting device on the pedestal, a transparent insulating plate on the nitride semiconductor light emitting device, a first electrode and a second electrode on the pedestal, and transparent insulation A transparent conductive film provided on the surface of the plate on the nitride semiconductor light emitting element side, the nitride semiconductor light emitting element having a first electrical connection portion and a second electrical connection portion, Provided is a nitride semiconductor light emitting device in which an electrode is electrically connected to a first electrical connection through a transparent conductive film, and a second electrode is electrically connected to the second electrical connection. be able to.

  According to the above-described embodiment, it is possible to provide a nitride semiconductor light emitting device capable of interrupting the supply of drive current to the nitride semiconductor light emitting element when the nitride semiconductor light emitting element is exposed to the outside.

1 is a schematic cross-sectional view of a nitride semiconductor light emitting device according to a first embodiment. 6 is a schematic cross-sectional view of a modified example of the nitride semiconductor light emitting device of the first embodiment. FIG. FIG. 5 is a schematic cross-sectional view of a nitride semiconductor light emitting device according to a second embodiment and a third embodiment. FIG. 10 is a schematic cross-sectional view of a modification of the nitride semiconductor light emitting device of the second and third embodiments. FIG. 7 is a schematic cross-sectional view of a nitride semiconductor light emitting device according to a fourth embodiment and a sixth embodiment. FIG. 10 is a schematic cross-sectional view of a nitride semiconductor light emitting device according to a fifth embodiment and a seventh embodiment. FIG. 10 is a schematic cross-sectional view of a modification of the nitride semiconductor light emitting device of the fourth embodiment and the sixth embodiment. FIG. 10 is a schematic cross-sectional view of a modification of the nitride semiconductor light emitting device of the fifth and seventh embodiments. FIG. 10 is a schematic cross-sectional view of a nitride semiconductor light emitting device according to an eighth embodiment. FIG. 29 is a schematic cross sectional view of a modification of the nitride semiconductor light emitting device of the eighth embodiment. It is typical sectional drawing of the conventional nitride semiconductor light-emitting device (nitride semiconductor light-emitting device of a comparative example).

  Hereinafter, an embodiment which is an example of the present invention will be described. Note that in the drawings used to describe the embodiments, the same reference numerals represent the same or corresponding parts.

<Embodiment 1>
[Configuration of nitride semiconductor light emitting device]
FIG. 1 is a schematic cross-sectional view of the nitride semiconductor light emitting device of the first embodiment. The nitride semiconductor light emitting device of the first embodiment includes a pedestal 4, a nitride semiconductor light emitting element 6 on the pedestal 4, a transparent insulating plate 1 on the nitride semiconductor light emitting element 6, and a nitride semiconductor of the transparent insulating plate 1. And a transparent conductive film 2 provided on the surface on the light emitting element 6 side.

  The pedestal 4 has a recess 41 in the center of the surface of the pedestal 4. The recess 41 has a square bottom surface 41a and a side surface 41b that extends obliquely upward from the periphery of the square bottom surface 41a and surrounds the bottom surface 41a. Further, the surface of the base 4 has a peripheral edge portion 42 provided so as to surround the recess 41. The first electrode 3 is provided on the surface of the peripheral portion 42 of the base 4 so as to surround the concave portion 41 of the base 4, and the second electrode 5 is provided on the bottom surface 41 a of the concave portion 41 of the base 4. It has been. In addition, the external shape of the bottom face 41a when the bottom face 41a is viewed from above is not particularly limited, but may be a square having a side of 1.5 cm, for example.

  As the pedestal 4, an insulating material can be used, and for example, an insulating ceramic, plastic, epoxy resin, or the like can be used. Moreover, as the 1st electrode 3 and the 2nd electrode 5, electroconductive members, such as a metal, can be used, for example.

  The nitride semiconductor light emitting element 6 is installed on the second electrode 5 on the bottom surface 41 a of the recess 41 of the pedestal 4. As the nitride semiconductor light emitting device 6, for example, a blue light emitting diode having a vertical structure including a stacked structure of an n-type GaN layer and a p-type GaN layer can be used.

  In the present embodiment, a case where a blue light emitting diode is used as the nitride semiconductor light emitting element 6 will be described. The blue light-emitting diode used as the nitride semiconductor light-emitting element 6 in the present embodiment has a configuration in which an n-electrode is provided on the lower surface of the n-type GaN layer, and the n-electrode is electrically connected to the second electrode 5. Connected. In addition, the p-type GaN layer that has been subjected to the p-type activation process is exposed on the upper surface, and the p-type GaN layer and the transparent conductive film 2 are electrically connected. Therefore, in the nitride semiconductor light emitting device 6 used in the present embodiment, the upper surface of the p-type GaN layer becomes the first electrical connection portion 61, and the lower surface of the n electrode becomes the second electrical connection portion 62. . The first electrical connecting portion 61 may be a member that can conduct with the first electrode 3, and the second electrical connecting portion 62 is a member that can conduct with the second electrode 5. I just need it. Further, in the present embodiment, only one blue light emitting diode is installed on the pedestal 4, but a plurality of blue light emitting diodes may be installed on the pedestal 4.

  The transparent conductive film 2 on the surface of the transparent insulating plate 1 on the side of the nitride semiconductor light emitting element 6 includes the first electrode 3 on the peripheral edge 42 of the base 4 and the first electrical connection portion 61 of the nitride semiconductor light emitting element 6. Are electrically connected to each other. Therefore, the first electrode 3 is electrically connected to the first electrical connecting portion 61 through the transparent conductive film 2.

  Here, as the transparent insulating plate 1, for example, a substrate made of sapphire, SiN (silicon nitride), glass or quartz can be used. Moreover, as the transparent conductive film 2, for example, ITO (Indium Tin Oxide) can be used. It is ideal that the transparent conductive film 2 has a transmittance of 100% of light emitted from the nitride semiconductor light emitting element 6, but at least a part of the light emitted from the nitride semiconductor light emitting element 6 is It only has to pass through. Therefore, the transmittance of light emitted from the nitride semiconductor light emitting element 6 in the transparent conductive film 2 may be, for example, 1% or less.

  The pedestal 4 is provided with a through hole 43a and a through hole 43b. The metal lead wire 7 electrically connected to the first electrode 3 is led out through the through hole 43a, and the metal lead wire 8 electrically connected to the second electrode 5 is drawn outside through the through hole 43b. Has been pulled out. Further, the vertical height h from the surface of the second electrode 5 to the surface of the peripheral edge portion 42 of the base 4 can be set to 500 μm, for example.

[Method for Manufacturing Nitride Semiconductor Light-Emitting Device]
An example of the method for manufacturing the nitride semiconductor light emitting device of the first embodiment will be described below. First, a sapphire substrate having a C surface having a thickness of 430 μm and a diameter of 2 inches is prepared as the transparent insulating plate 1. Here, the sapphire substrate is preferably polished on both sides.

  Next, a transparent conductive film 2 made of ITO having a thickness of 250 nm is formed on one surface of the transparent insulating plate 1 made of the sapphire substrate by, for example, sputtering. In the present embodiment, ITO is used as the transparent conductive film 2, but is not limited to ITO. For example, a metal thin film in which a Ni film and an Au film are stacked (from several angstroms to several tens of nanometers, Further, a thickness greater than that may be used), or a metal thin film of Pt, Pd, Cu, or Ag may be used. In addition, it is preferable to adjust the thickness of the transparent conductive film 2 in the case of using a metal thin film for the transparent conductive film 2 to such a thickness that the light emitted from the nitride semiconductor light emitting element 6 is transmitted.

  Next, in order to match the transparent insulating plate 1 after the formation of the transparent conductive film 2 with the shape of the peripheral portion 42 of the pedestal 4, the transparent insulating plate 1 is formed into a square shape having a side of 1.5 cm using a dicing apparatus. The transparent insulating plate 1 is covered so that the transparent conductive film 2 on one side covers the base 4. At this time, the first electrode 3 placed on the surface of the peripheral portion 42 of the base 4 and the transparent conductive film 2 are in contact with each other, and the p-type GaN layer of the nitride semiconductor light emitting element 6 is in contact with the transparent conductive film 2. . Thereby, the p-type GaN layer on the upper side of the nitride semiconductor light emitting element 6 is electrically connected to the first electrode 3 and the metal lead wire 7 through the transparent conductive film 2. The n-type GaN layer below the nitride semiconductor light emitting element 6 is electrically connected to the second electrode 5 and the metal lead wire 8 through the n electrode. The nitride semiconductor light emitting element 6 can be manufactured by a conventionally known method such as metal organic chemical vapor deposition.

  The fixing means for the transparent insulating plate 1 is not particularly limited. For example, the transparent insulating plate 1 may be fixed to the peripheral portion 42 of the pedestal 4 with a resin or the like. For example, the transparent insulating plate 1 may be sandwiched and fixed.

[Evaluation of nitride semiconductor light emitting device]
When a forward drive current of 20 mA was applied by current control between the metal lead wire 7 and the metal lead wire 8 of the nitride semiconductor light emitting device of the first embodiment manufactured as described above, the metal lead wire 7 and The voltage between the metal lead wire 8 was 3.6 V, and the nitride semiconductor light emitting element 6 emitted blue light.

  In order to confirm the effect of the nitride semiconductor light emitting device of the first embodiment, it is assumed that the transparent insulating plate 1 of the nitride semiconductor light emitting device of the first embodiment is detached due to an accident or the like. The plate 1 was removed from the base 4. As a result, blue light is no longer observed from the nitride semiconductor light emitting element 6 that exhibited blue light emission. Further, the voltage between the metal lead wire 7 and the metal lead wire 8 was opened.

  This is because when the transparent insulating plate 1 is detached from the pedestal 4, the transparent conductive film 2 formed on the transparent insulating plate 1 is also detached from the first electrode 3 at the same time, so that the drive current is cut off. This is because the operation No. 6 has stopped.

  For comparison, a conventional nitride semiconductor light emitting device (a nitride semiconductor light emitting device of a comparative example) shown in the schematic cross-sectional view of FIG. 11 was produced. The nitride semiconductor light emitting device of the comparative example shown in FIG. 11 is different from the nitride semiconductor light emitting device of the first embodiment in that conduction is achieved using a metal wire 9 instead of the transparent conductive film 2.

  That is, in the nitride semiconductor light emitting device of the comparative example, the first electrical connection portion 61 on the top of the nitride semiconductor light emitting element 6 is electrically connected to the first electrode 3 through the metal wire 9. . The first electrode 3 is electrically connected to the metal lead wire 7 drawn out of the base 4 through the through hole 43a. That is, the first electrical connecting portion 61 of the nitride semiconductor light emitting element 6 is electrically connected to the first metal lead 7 via the metal wire 9 and the first electrode 3.

  Similarly to the nitride semiconductor light emitting device of the first embodiment, in the nitride semiconductor light emitting device of the comparative example, the second electrical connection portion 62 on the lower side of the nitride semiconductor light emitting element 6 has the second electrode. 5 is electrically connected to the metal lead wire 8 drawn to the outside of the base 4 through the through hole 43b.

  When a forward drive current of 20 mA is applied between the metal lead wire 7 and the metal lead wire 8 of the nitride semiconductor light emitting device of the comparative example by current control, the voltage between the metal lead wire 7 and the metal lead wire 8 is applied. Was 3.6 V, and the nitride semiconductor light emitting device 6 emitted blue light. However, although the transparent insulating plate 1 was removed from the pedestal 4 using ceramic tweezers, blue light continued to be emitted from the nitride semiconductor light emitting element 6 that exhibited blue light emission. Thereby, the effect of the nitride semiconductor light-emitting device of Embodiment 1 was confirmed.

[Function and effect]
As shown in FIG. 11, in the conventional nitride semiconductor light emitting device, a drive current is supplied to the nitride semiconductor light emitting element 6 using one or a plurality of metal wires 9. Therefore, in the conventional nitride semiconductor light-emitting device, even if the transparent insulating plate 1 is removed due to an accident or the like, the nitride semiconductor light-emitting device has no effect on the drive current supply circuit of the nitride semiconductor light-emitting element 6. Light continued to be emitted from the light emitting element 6.

  However, in the nitride semiconductor light emitting device of the first embodiment, the transparent conductive film 2 attached to the transparent insulating plate 1 is incorporated in the drive current supply circuit of the nitride semiconductor light emitting element 6, so that it may be caused by an accident or the like. When the transparent insulating plate 1 is removed, the transparent conductive film 2 together with the transparent insulating plate 1 is removed from the drive current supply circuit of the nitride semiconductor light emitting element 6. Therefore, in the nitride semiconductor light emitting device of the first embodiment, it is possible to cut off the supply of drive current to nitride semiconductor light emitting element 6 when nitride semiconductor light emitting element 6 is exposed to the outside. That is, in the nitride semiconductor light emitting device of the first embodiment, the adhesive force between the transparent insulating plate 1 and the transparent conductive film 2 is stronger than the adhesive force between the transparent conductive film 2 and the first electrode 3. I just need it.

[Other Embodiments of Nitride Semiconductor Light-Emitting Device]
In the first embodiment, the case where a blue light emitting diode having a structure in which the p-type nitride semiconductor layer is on the upper side and the n-type nitride semiconductor layer is on the lower side is used as the nitride semiconductor light emitting element 6 is described. For example, a blue light emitting diode having a structure in which the n-type nitride semiconductor layer is on the upper side and the p-type nitride semiconductor layer is on the lower side may be used.

  In the first embodiment, the case where a vertical blue light emitting diode is used as the nitride semiconductor light emitting element 6 has been described. However, the present invention is not limited to this. For example, a horizontal blue light emitting diode may be used. When a blue light emitting diode having a lateral structure is used, for example, the p electrode electrically connected to the p-type nitride semiconductor layer and the n electrode electrically connected to the n-type nitride semiconductor layer are both on the upper side, and p Either the p electrode or the n electrode is electrically connected to the transparent conductive film 2 so that the electrode and the n electrode are not short-circuited, and the other is electrically connected to the second electrode 5 using a metal wire or the like. By connecting, a drive current supply circuit to the nitride semiconductor light emitting element 6 can be formed.

<Modification of Embodiment 1>
FIG. 2 is a schematic cross-sectional view of a modification of the nitride semiconductor light emitting device of the first embodiment. In the modification shown in FIG. 2, the transparent insulating plate 1, the transparent conductive film 2, and the first electrode 3 are provided with a peripheral edge portion 42a of the base 4 protruding upward so as not to be exposed to the outside. It is said. Since the transparent conductive film 2 and the first electrode 3 can be prevented from being exposed to the outside by the peripheral edge portion 42a of the pedestal 4 protruding upward, the leakage from the transparent conductive film 2 and the first electrode 3 and the like The occurrence of electrical problems can be prevented. From the viewpoint of preventing the occurrence of electrical problems such as electric leakage, at least the transparent conductive film 2 and the first electrode 3 are prevented from being exposed to the outside by the peripheral portion 42a of the base 4 protruding upward. I can do it.

<Embodiment 2>
FIG. 3 is a schematic cross-sectional view of the nitride semiconductor light emitting device of the second embodiment. The nitride semiconductor light emitting device of the second embodiment is characterized in that a phosphor plate 10 is provided on the surface of the transparent insulating plate 1 opposite to the side where the transparent conductive film 2 is installed.

  The phosphor plate 10 is not particularly limited as long as it is a plate-like material including a phosphor produced by a conventionally known method, but in this embodiment, one side containing a YAG phosphor is 1.5 cm. A 500 μm thick resin plate having a square surface is used. Further, although the method for fixing the phosphor plate 10 is not particularly limited, in the present embodiment, an adhesive material is applied to the periphery of the phosphor plate 10 and then fixed on the transparent insulating plate 1.

  In order to drive the nitride semiconductor light emitting device of the second embodiment, a driving current of 20 mA is applied between the metal lead wire 7 and the metal lead wire 8 in the same manner as the nitride semiconductor light emitting device of the first embodiment. White light was observed from the upper surface of the nitride semiconductor light emitting device. This is because the yellow phosphor of the phosphor plate 10 is excited by a part of the light of the blue light emitting diode which is the nitride semiconductor light emitting element 6 to emit yellow light, and the remaining blue light is emitted from the blue light emitting diode. This is because the color looks white. Also in the second embodiment, only one blue light emitting diode is installed on the pedestal 4, but a plurality of blue light emitting diodes may be installed on the pedestal 4.

  In the nitride semiconductor light emitting device of the second embodiment, the transparent insulating plate 1 was removed from the pedestal 4 using ceramic tweezers as in the nitride semiconductor light emitting device of the first embodiment. As a result, blue light from the blue light emitting diode was not observed. Thereby, the same effect as the nitride semiconductor light-emitting device of Embodiment 1 was confirmed for the nitride semiconductor light-emitting device of Embodiment 2.

  Since the description other than the above in the second embodiment is the same as that in the first embodiment, the description thereof is omitted here.

<Embodiment 3>
In the nitride semiconductor light emitting device of the third embodiment, a near ultraviolet light emitting diode having an emission wavelength of 365 nm is used as the nitride semiconductor light emitting element 6, and an RGB phosphor (ultraviolet light) is used as the phosphor contained in the phosphor plate 10. It has the same structure as the nitride semiconductor light emitting device of the second embodiment except that a phosphor that is excited by light and exhibits blue, green, and red fluorescence is used. In the phosphor plate 10 according to the third embodiment, the phosphor concentration in the phosphor plate 10 is adjusted so that the near-ultraviolet light is attenuated to an intensity of 1/1000 while passing through the phosphor plate 10. .

  When a drive current of 60 mA was applied between the metal lead wire 7 and the metal lead wire 8 in order to drive the nitride semiconductor light emitting device of the third embodiment, white light was observed from the upper surface of the nitride semiconductor light emitting device. It was. This is because the RGB phosphors are excited by the light of the near-ultraviolet light-emitting diode, which is the nitride semiconductor light-emitting element 6, and light exhibiting blue, green, and red is emitted. In Embodiment 3, only one near ultraviolet light emitting diode is installed on the pedestal 4, but a plurality of near ultraviolet light emitting diodes may be installed on the pedestal 4.

  Also, in the nitride semiconductor light emitting device of the third embodiment, the transparent insulating plate 1 was removed from the pedestal 4 using ceramic tweezers as in the first embodiment. As a result, near ultraviolet light from the near ultraviolet light emitting diode was not observed. Thereby, the same effect as the nitride semiconductor light-emitting device of Embodiment 1 was confirmed for the nitride semiconductor light-emitting device of Embodiment 3. For safety, observation of near-ultraviolet light from near-ultraviolet light-emitting diodes is performed using a spectroscope and a multi-channel CCD (Charge Coupled Device) wearing protective goggles in a booth covered with a black screen. It was.

  Since the description other than the above in the third embodiment is the same as that in the first and second embodiments, the description thereof is omitted here.

<Modifications of Embodiment 2 and Embodiment 3>
FIG. 4 is a schematic cross-sectional view of a modification of the nitride semiconductor light emitting device of the second and third embodiments. In the modification shown in FIG. 4, the transparent insulating plate 1, the transparent conductive film 2, the first electrode 3, and the phosphor plate 10 have a peripheral portion 42 a of the pedestal 4 protruding upward so as not to be exposed to the outside. It is characterized by having. Since the transparent conductive film 2 and the first electrode 3 can be prevented from being exposed to the outside by the peripheral edge portion 42a of the pedestal 4 protruding upward, the leakage from the transparent conductive film 2 and the first electrode 3 and the like The occurrence of electrical problems can be prevented. From the viewpoint of preventing the occurrence of electrical problems such as electric leakage, at least the transparent conductive film 2 and the first electrode 3 are prevented from being exposed to the outside by the peripheral portion 42a of the base 4 protruding upward. I can do it.

<Embodiment 4>
FIG. 5 is a schematic cross-sectional view of the nitride semiconductor light emitting device of the fourth embodiment. The nitride semiconductor light emitting device of the fourth embodiment has the same structure as the nitride semiconductor light emitting device of the third embodiment except that the phosphor plate 10 is provided between the transparent insulating plate 1 and the transparent conductive film 2. have. That is, also in Embodiment 4, only one near ultraviolet light emitting diode may be installed on the pedestal 4, or a plurality of near ultraviolet light emitting diodes may be installed.

  In the nitride semiconductor light emitting device of the fourth embodiment, for example, a phosphor plate 10 having a thickness of 500 μm is formed in advance on the lower surface of the transparent insulating plate 1, and then the phosphor plate is formed in the same manner as in the first embodiment. It can be produced by forming the transparent conductive film 2 on 10.

  The effect of the nitride semiconductor light emitting device of the fourth embodiment was also confirmed in the same manner as the nitride semiconductor light emitting device of the third embodiment. As a result, the same effect as the nitride semiconductor light emitting device of the third embodiment was obtained. confirmed. That is, in the nitride semiconductor light emitting device of the fourth embodiment, the adhesive force between the transparent conductive film 2 and the phosphor plate 10 is stronger than the adhesive force between the transparent conductive film 2 and the first electrode 3. I just need it.

  Since the description other than the above in the fourth embodiment is the same as that in the first to third embodiments, the description thereof is omitted here.

<Embodiment 5>
FIG. 6 is a schematic cross-sectional view of the nitride semiconductor light emitting device of the fifth embodiment. The nitride semiconductor light-emitting device of the fifth embodiment is the same as the nitride semiconductor light-emitting device of the third embodiment except that the RGB phosphor 11 is dispersed in the transparent insulating plate 1 instead of the phosphor plate 10. It has the structure of. That is, also in Embodiment 5, only one near ultraviolet light emitting diode may be installed on the pedestal 4 or a plurality of near ultraviolet light emitting diodes may be installed.

  The transparent insulating plate 1 in which the RGB phosphors 11 are dispersed can be produced, for example, in the same manner as the phosphor plate 10 of the second to fourth embodiments.

  With respect to the nitride semiconductor light emitting device of the fifth embodiment, the effects were confirmed in the same manner as the nitride semiconductor light emitting device of the third embodiment. As a result, the same effects as the nitride semiconductor light emitting device of the third embodiment were obtained. confirmed.

  Since the description other than the above in the fifth embodiment is the same as that in the first to fourth embodiments, the description thereof is omitted here.

<Embodiment 6>
The nitride semiconductor light emitting device of the sixth embodiment is the same as that of the fourth embodiment except that a blue light emitting diode element is used as the nitride semiconductor light emitting element 6 and a phosphor plate containing a yellow phosphor is used as the phosphor plate 10. It has the same structure as the nitride semiconductor light emitting device. That is, also in Embodiment 6, only one near ultraviolet light emitting diode may be installed on the pedestal 4, or a plurality of near ultraviolet light emitting diodes may be installed.

  The effect of the nitride semiconductor light emitting device of the sixth embodiment was also confirmed in the same manner as the nitride semiconductor light emitting device of the third embodiment. As a result, the same effect as the nitride semiconductor light emitting device of the third embodiment was obtained. confirmed.

  Since the description other than the above in the sixth embodiment is the same as that in the first to fifth embodiments, the description thereof is omitted here.

<Embodiment 7>
The nitride semiconductor light emitting device of the seventh embodiment uses a blue light emitting diode element as the nitride semiconductor light emitting element 6, and the transparent insulating plate 1 includes the yellow phosphor instead of the RGB phosphor. It has the same structure as the nitride semiconductor light emitting device. That is, also in Embodiment 7, only one near ultraviolet light emitting diode may be installed on the pedestal 4, or a plurality of near ultraviolet light emitting diodes may be installed.

  As for the nitride semiconductor light emitting device of the seventh embodiment, the operational effects were confirmed in the same manner as the nitride semiconductor light emitting device of the third embodiment, and the same operational effects as the nitride semiconductor light emitting device of the third embodiment were obtained. confirmed.

  Since the description other than the above in the seventh embodiment is the same as that in the first to sixth embodiments, the description thereof is omitted here.

<Modification of Embodiment 4 and Embodiment 6>
FIG. 7 is a schematic cross-sectional view of a modification of the nitride semiconductor light emitting device of the fourth and sixth embodiments. In the modification shown in FIG. 7, the transparent insulating plate 1, the transparent conductive film 2, the first electrode 3, and the phosphor plate 10 have a peripheral portion 42a of the base 4 protruding upward so as not to be exposed to the outside. It is characterized by having. Since the transparent conductive film 2 and the first electrode 3 can be prevented from being exposed to the outside by the peripheral edge portion 42a of the pedestal 4 protruding upward, the leakage from the transparent conductive film 2 and the first electrode 3 and the like The occurrence of electrical problems can be prevented. From the viewpoint of preventing the occurrence of electrical problems such as electric leakage, at least the transparent conductive film 2 and the first electrode 3 are prevented from being exposed to the outside by the peripheral portion 42a of the base 4 protruding upward. I can do it.

<Modification of Embodiment 5 and Embodiment 7>
FIG. 8 is a schematic cross-sectional view of a modification of the nitride semiconductor light emitting device of the fifth and seventh embodiments. In the modification shown in FIG. 8, the transparent insulating plate 1, the transparent conductive film 2 and the first electrode 3 are provided with a peripheral portion 42a of the base 4 protruding upward so as not to be exposed to the outside. It is said. Since the transparent conductive film 2 and the first electrode 3 can be prevented from being exposed to the outside by the peripheral edge portion 42a of the pedestal 4 protruding upward, the leakage from the transparent conductive film 2 and the first electrode 3 and the like The occurrence of electrical problems can be prevented. From the viewpoint of preventing the occurrence of electrical problems such as electric leakage, at least the transparent conductive film 2 and the first electrode 3 are prevented from being exposed to the outside by the peripheral portion 42a of the base 4 protruding upward. I can do it.

<Eighth embodiment>
FIG. 9 is a schematic cross-sectional view of the nitride semiconductor light emitting device of the eighth embodiment. In the nitride semiconductor light emitting device of the eighth embodiment, a connection electrode 71 is provided on the p-type GaN layer on the upper side of the blue light emitting diode as the nitride semiconductor light emitting element 6, and the connection electrode 71, the transparent conductive film 2, and the like. The structure is the same as that of the nitride semiconductor light-emitting device of the first embodiment except that they are in contact with each other. In this case, the first electrical connection portion 61 of the nitride semiconductor light emitting element 6 becomes the surface of the p-type GaN layer connected to the connection electrode 71.

  As for the nitride semiconductor light emitting device of the eighth embodiment, the effects were confirmed in the same manner as the nitride semiconductor light emitting device of the first embodiment. As a result, the same effects as the nitride semiconductor light emitting device of the first embodiment were obtained. confirmed.

  Also in the nitride semiconductor light emitting devices of the second to seventh embodiments, similarly to the nitride semiconductor light emitting device of the eighth embodiment, the p-type above the blue light emitting diode as the nitride semiconductor light emitting element 6 is used. When the connection electrode 71 is installed on the GaN layer and the effects are confirmed in the same manner as the nitride semiconductor light emitting device of the eighth embodiment, the same effects as the nitride semiconductor light emitting device of the eighth embodiment are confirmed. Was confirmed.

  The connection electrode 71 may be, for example, a transparent electrode made of the same material as the transparent conductive film 2. Also in the eighth embodiment, only one blue light emitting diode may be installed on the pedestal 4 or a plurality of blue light emitting diodes may be installed.

  Since the description other than the above in the eighth embodiment is the same as that in the first to seventh embodiments, the description thereof is omitted here.

<Modification of Embodiment 8>
FIG. 10 is a schematic cross-sectional view of a modification of the nitride semiconductor light emitting device of the eighth embodiment. In the modification shown in FIG. 10, the peripheral part 42a of the base 4 protruded upward is provided so that the transparent insulating plate 1, the transparent conductive film 2, and the first electrode 3 are not exposed to the outside. It is said. Since the transparent conductive film 2 and the first electrode 3 can be prevented from being exposed to the outside by the peripheral edge portion 42a of the pedestal 4 protruding upward, the leakage from the transparent conductive film 2 and the first electrode 3 and the like The occurrence of electrical problems can be prevented. From the viewpoint of preventing the occurrence of electrical problems such as electric leakage, at least the transparent conductive film 2 and the first electrode 3 are prevented from being exposed to the outside by the peripheral portion 42a of the base 4 protruding upward. I can do it.

<Embodiment 9>
The nitride semiconductor light emitting device of the ninth embodiment is characterized in that graphene is used for the transparent conductive film 2 of the nitride semiconductor light emitting device of the first to eighth embodiments. The effects of the nitride semiconductor light emitting device of the ninth embodiment were also confirmed in the same manner as the nitride semiconductor light emitting device of the first to eighth embodiments, and the nitride of the first to eighth embodiments was confirmed. The same effect as the semiconductor light emitting device was confirmed. Also in the ninth embodiment, only one light emitting diode may be installed on the pedestal 4 or a plurality of light emitting diodes may be installed.

  Graphene is a two-dimensional (xy plane) arrangement of carbon atoms with σ bonds by sp2 hybrid orbitals, and the remaining π electrons by pz orbitals have a degree of freedom in the plane. The layer made of graphene constituting the transparent conductive film 2 may be either a single layer or a plurality of layers.

  As the material of the transparent conductive film 2, it is preferable to use a material having a high transmittance with respect to the light emitted from the nitride semiconductor light emitting element 6, so that the transmittance and thermal characteristics of graphene, ITO and other metals will be described below. explain.

Graphene is a single layer, and the relationship between energy and wave number k is linear and has no band gap. Due to this unique band structure, in-plane carrier mobility is said to be 10,000 to 200,000 cm ² / Vs in graphene. This means that the carrier mobility in the surface of graphene is high, the saturation current density is larger than that of other semiconductors, and the current flows easily. Therefore, it is considered that one to several layers of graphene are sufficient.

[Transmissivity]
The absorption rate of light per layer of graphene has a constant value of 2.3% regardless of the wavelength of light in the infrared, visible, and ultraviolet wavelength ranges, and the remaining light is transmitted. On the other hand, since ITO has a band gap of 3.75 eV (corresponding to the energy of light having a wavelength of 330 nm), although it depends on the film thickness, it is generally a practical thickness and approximately 80% or more in the visible region. Although it is designed to have transmittance, absorption becomes remarkable in a wavelength region called deep ultraviolet having a wavelength of about 200 nm, and the transmittance becomes extremely low. In addition, other metals generally have a high reflectance from the visible to the near ultraviolet due to a high plasma frequency of free electrons, and an absorptivity in the deep ultraviolet. Therefore, since graphene can express a high transmittance regardless of the wavelength of light, it is considered that the graphene has preferable characteristics as a material of the transparent conductive film 2 compared with ITO and other metals. .

[Thermal characteristics]
The thermal conductivity of graphene is 5000 W / m / K or more, the thermal conductivity of ITO is about 80 W / m / K, and the thermal conductivity of Au is about 320 W / m / K. The thermal conductivity of sapphire used for the transparent insulating plate 1 is about 40 W / m / K, and the thermal conductivity of glass is 1 W / m / K.

  Therefore, the nitride semiconductor light emitting element 6 emits not a little heat, but by using graphene for the transparent conductive film 2, the heat can be discharged, and the reliability of the nitride semiconductor light emitting device can be improved. .

  Examples of the method for producing graphene include exfoliation from graphite (Scotch tape method), vacuum pyrolysis of a SiC epitaxial growth layer, or chemical vapor deposition using a metal catalyst, but the method for producing graphene is not particularly limited.

  In addition to graphene, when the transparent conductive film 2 is also used as graphite carbon nanotubes having a structure in which a plurality of graphenes are laminated, or two or more composites selected from the group consisting of graphene, graphite, and carbon nanotubes In addition, the same operational effects as those of the nitride semiconductor light emitting devices of the first to ninth embodiments can be confirmed.

  Further, as the transparent conductive film 2 of the nitride semiconductor light emitting device of the first to ninth embodiments, AlN (aluminum nitride), AlGaN (aluminum gallium nitride), AlInGaN (aluminum indium gallium nitride), InGaN (indium gallium nitride) ), GaN (gallium nitride), InN (indium nitride), ITO, ZnO (zinc oxide), MgZnO (magnesium zinc oxide), and a material containing at least one selected from the group consisting of IGZO (indium gallium zinc oxide) Even when used, the same operational effects as those of the nitride semiconductor light emitting devices of the first to ninth embodiments can be confirmed.

<Appendix>
(1) According to an embodiment of the present invention, a base, a nitride semiconductor light emitting element on the base, a transparent insulating plate on the nitride semiconductor light emitting element, a first electrode and a second electrode on the base, A transparent conductive film provided on the surface of the transparent insulating plate on the nitride semiconductor light emitting element side, the nitride semiconductor light emitting element having a first electrical connection portion and a second electrical connection portion, One electrode is electrically connected to the first electrical connection portion through a transparent conductive film, and the second electrode is a nitride semiconductor light emitting device electrically connected to the second electrical connection portion. Can be provided. By adopting such a configuration, the transparent conductive film provided on the transparent insulating plate is incorporated in the drive current supply circuit of the nitride semiconductor light-emitting element, so when the transparent insulating plate is removed due to an accident or the like. The transparent conductive film together with the transparent insulating plate can be removed from the drive current supply circuit of the nitride semiconductor light emitting device. Therefore, it is possible to cut off the supply of drive current to the nitride semiconductor light emitting device when the nitride semiconductor light emitting device is exposed to the outside.

  (2) A nitride semiconductor light emitting device according to an embodiment of the present invention includes a transparent insulating plate on a surface opposite to the nitride semiconductor light emitting element side surface, between the transparent insulating plate and the transparent conductive film, and transparent insulation. A phosphor that emits visible light when excited by light emitted from the nitride semiconductor light emitting element may be provided at at least one location selected from the group consisting of the inside of the plate. In this case, light of various types can be emitted from the nitride semiconductor light emitting device according to the embodiment of the present invention.

  (3) In the nitride semiconductor light emitting device according to the embodiment of the present invention, the nitride semiconductor light emitting element may be provided with a connection electrode, and the transparent conductive film and the connection electrode may be electrically connected. . Also in this case, it is possible to exhibit an effect that the supply of drive current to the nitride semiconductor light emitting device when the nitride semiconductor light emitting device is exposed to the outside can be cut off.

  (4) In the nitride semiconductor light emitting device of the embodiment of the present invention, the transparent conductive film may contain at least one selected from the group consisting of graphite, graphene, and carbon nanotubes. Also in this case, it is possible to exhibit an effect that the supply of drive current to the nitride semiconductor light emitting device when the nitride semiconductor light emitting device is exposed to the outside can be cut off.

  (5) In the nitride semiconductor light emitting device of the embodiment of the present invention, the transparent conductive film is at least one selected from the group consisting of AlN, AlGaN, AlInGaN, InGaN, GaN, InN, ITO, ZnO, MgZnO, and IGZO. May be included. Also in this case, it is possible to exhibit an effect that the supply of drive current to the nitride semiconductor light emitting device when the nitride semiconductor light emitting device is exposed to the outside can be cut off.

  As described above, the embodiments of the present invention have been described, but it is also planned from the beginning to appropriately combine the configurations of the above-described embodiments.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The present invention can be used for a nitride semiconductor light-emitting device, and can be particularly suitably used for a nitride semiconductor light-emitting device as an illumination light source.

  DESCRIPTION OF SYMBOLS 1 Transparent insulating board, 2 Transparent electrically conductive film, 3 1st electrode, 4 base, 5 2nd electrode, 6 Nitride semiconductor light-emitting device, 7, 8 Metal lead wire, 9 Metal wire, 10 Phosphor plate, 11 Fluorescence Body, 41 concave portion, 41a bottom surface of concave portion, 41b side surface of concave portion, 42, 42a peripheral edge portion, 43a, 43b through-hole, 61 first electric connecting portion, 62 second electric connecting portion.

Claims (5)

A pedestal,
A nitride semiconductor light emitting device on the pedestal;
A transparent insulating plate on the nitride semiconductor light emitting device;
A first electrode and a second electrode on the pedestal;
A transparent conductive film provided on the surface of the transparent insulating plate on the nitride semiconductor light emitting element side, and
The nitride semiconductor light emitting device has a first electrical connection portion and a second electrical connection portion,
The first electrode is electrically connected to the first electrical connection portion via the transparent conductive film,
The nitride semiconductor light emitting device, wherein the second electrode is electrically connected to the second electrical connection portion.   At least selected from the group consisting of the transparent insulating plate on the surface opposite to the nitride semiconductor light emitting element side surface, between the transparent insulating plate and the transparent conductive film, and the inside of the transparent insulating plate The nitride semiconductor light-emitting device according to claim 1, further comprising a phosphor that emits visible light when excited by light emitted from the nitride semiconductor light-emitting element. A connection electrode is provided on the nitride semiconductor light emitting device,
The nitride semiconductor light-emitting device according to claim 1, wherein the transparent conductive film and the connection electrode are electrically connected.   The nitride semiconductor light-emitting device according to any one of claims 1 to 3, wherein the transparent conductive film includes at least one selected from the group consisting of graphite, graphene, and carbon nanotubes.   5. The transparent conductive film according to claim 1, wherein the transparent conductive film includes at least one selected from the group consisting of AlN, AlGaN, AlInGaN, InGaN, GaN, InN, ITO, ZnO, MgZnO, and IGZO. The nitride semiconductor light-emitting device described in 1.

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