JP2012023280A - Semiconductor light-emitting element, light-emitting device, lighting device, display device, signal light and road information device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor light-emitting element, a light-emitting device, a lighting device, a display device, a signal light and a road information device which can provide protection against static electricity and an excess voltage without providing a protection element outside.SOLUTION: A semiconductor layer for a light-emitting element layered with an n-type semiconductor layer 2, an active layer and a p-type semiconductor layer 3 is formed on a substrate 1. On a surface of the light-emitting element 100, a first bonding electrode 81 and a second bonding electrode 82 at appropriate intervals are provided. Below the first bonding electrode 81, an n-type semiconductor layer 12 for a protection element is formed isolated from the n-type semiconductor layer 2 for the light-emitting element. On the n-type semiconductor layer 12 for the protection element, an active layer and a p-type semiconductor layer 13 are layered. The n-type semiconductor layer 12, the active layer and the p-type semiconductor layer 13 form a semiconductor layer for the protection element.

Description

  The present invention relates to a semiconductor light emitting device in which a semiconductor layer in which an n-type semiconductor layer, an active layer, and a p-type semiconductor layer are stacked on a substrate, a light emitting device including the semiconductor light emitting device, a lighting device including the light emitting device, and a display The present invention relates to a device, a signal lamp, and a road information device.

  Light emitting diodes have been attracting attention as a light source because of their low power consumption and long life compared to fluorescent lamps and incandescent lamps that have been used as light sources in the past. It has come to be used in a wide range of fields, such as backlight light sources, illumination light sources, and amusement equipment decorations.

  Such light-emitting diodes can emit required single colors such as blue, blue-green, green and red according to the application, or can emit red, green and blue multicolors in one package. is there. In addition, light-emitting diodes that can emit white light in combination with phosphors have been commercialized.

  For example, a white light-emitting diode (light-emitting device) having a surrounding portion that surrounds an LED chip (semiconductor light-emitting element), including a phosphor that emits light when excited by light of a predetermined wavelength, and has good light emission efficiency and light emission intensity It is disclosed (see Patent Document 1).

JP 2004-161789 A

  However, in order to protect the light emitting diode (light emitting device) of Patent Document 1 from static electricity or overvoltage, it is necessary to connect a protective element outside the light emitting diode, which increases the number of components and increases the cost. . In particular, in devices using a large number of light emitting diodes, it is necessary to connect protective elements according to the number of light emitting diodes, and the number of protective elements also increases, reducing the number of components, saving space, or reducing costs. It was a problem from the viewpoint.

  The present invention has been made in view of such circumstances, and includes a semiconductor light-emitting element that can be protected from static electricity and overvoltage without providing a protective element outside, a light-emitting device including the semiconductor light-emitting element, and the light-emitting device. An object is to provide a lighting device, a display device, a signal lamp, and a road information device.

  According to a first aspect of the present invention, there is provided a semiconductor light emitting device in which a semiconductor layer in which an n type semiconductor layer, an active layer, and a p type semiconductor layer for a light emitting device are stacked is formed on the substrate. An n-type semiconductor layer for a protective element formed separately from the semiconductor layer, a semiconductor layer in which an active layer and a p-type semiconductor layer are stacked, and the semiconductor layer for the protective element is an n-type semiconductor layer for the light-emitting element Alternatively, it is formed below the bonding electrode connected to the p-type semiconductor layer.

  A semiconductor light emitting device according to a second invention is the semiconductor light emitting device according to the first invention, wherein a first bonding electrode connected to the p-type semiconductor layer for the light emitting device and a second bonding electrode connected to the n-type semiconductor layer for the light emitting device. An n-type semiconductor layer for the protective element is connected to the first bonding electrode, and a p-type semiconductor layer for the protective element is connected to the n-type semiconductor layer for the light-emitting element. The protective element semiconductor layer is formed below the first bonding electrode.

  A semiconductor light emitting device according to a third invention is the semiconductor light emitting device according to the first invention, wherein the first bonding electrode connected to the p-type semiconductor layer for the light emitting device and the second bonding electrode connected to the n-type semiconductor layer for the light emitting device. A p-type semiconductor layer for the protective element is connected to the second bonding electrode, and an n-type semiconductor layer for the protective element is connected to the p-type semiconductor layer for the light-emitting element. The protective element semiconductor layer is formed below the second bonding electrode.

  According to a fourth aspect of the present invention, there is provided a semiconductor light emitting device according to the first aspect, wherein the first and second protective element n-type semiconductor layers, active layers and p formed on the substrate separately from the n-type semiconductor layer. Two separated semiconductor layers having stacked type semiconductor layers, a first bonding electrode connected to the p-type semiconductor layer for the light emitting element, and a second connected to the n-type semiconductor layer for the light emitting element. A n-type semiconductor layer for the first protection element is connected to the first bonding electrode, and a p-type semiconductor layer for the first protection element is connected to the second protection element. A p-type semiconductor layer for the second protection element is connected to the second bonding electrode, and a semiconductor layer for the first protection element is connected to the second protection element. Formed on the lower side of the first bonding electrode, and the second Characterized in that the semiconductor layer of the protection element is formed on the lower side of the second bonding electrodes.

  A light-emitting device according to a fifth aspect of the present invention includes the semiconductor light-emitting element according to any one of the first to fourth aspects of the present invention and a housing portion that houses the semiconductor light-emitting element.

  A lighting device according to a sixth aspect of the invention includes the light emitting device according to the fifth aspect of the invention.

  A display device according to a seventh aspect includes the light emitting device according to the fifth aspect.

  A signal lamp device according to an eighth aspect of the invention includes the light emitting device according to the fifth aspect of the invention.

  A road information device according to a ninth aspect includes the light emitting device according to the fifth aspect.

  In the first invention, the semiconductor device includes a semiconductor layer in which an n-type semiconductor layer for a protective element, an active layer, and a p-type semiconductor layer, which are formed separately from an n-type semiconductor layer for a light-emitting element on a substrate, A protective element semiconductor layer is formed under the bonding electrode connected to the light emitting element n-type semiconductor layer or p-type semiconductor layer. Since a semiconductor layer for a protective element is included in one semiconductor light emitting element, it is not necessary to connect the protective element to the outside of the semiconductor light emitting element, and a semiconductor light emitting element having high reliability against static electricity or overvoltage is realized. Can do. Further, since there is no need to connect a protective element outside the semiconductor light emitting element, it is possible to reduce the number of parts, save space, or reduce the cost. Furthermore, since the semiconductor layer for the protective element is provided under the bonding electrode, the light emitting area of the semiconductor light emitting element is not affected, so that the light emitting efficiency can be maintained without affecting the light emitting efficiency of the semiconductor light emitting element.

  The second invention includes a first bonding electrode connected to the p-type semiconductor layer for the light-emitting element and a second bonding electrode connected to the n-type semiconductor layer for the light-emitting element. The protective element n-type semiconductor layer is connected to the first bonding electrode, the protective element p-type semiconductor layer is connected to the light emitting element n-type semiconductor layer, and the protective element semiconductor A layer is formed under the first bonding electrode. A p-type semiconductor layer for a light-emitting element and an n-type semiconductor layer for a protection element are connected to the first bonding electrode, and an n-type semiconductor layer for a light-emitting element is connected to the second bonding electrode to emit light. A p-type semiconductor layer for a protection element is connected to the n-type semiconductor layer for the element.

  That is, a semiconductor layer for a protective element (LED structure) connected in reverse parallel to a semiconductor layer for a light emitting element (LED structure) is incorporated in one semiconductor light emitting element, and the semiconductor layer for the protective element is first bonded. Provided under the electrode. Since the light emitting element and the protective element are included in one semiconductor light emitting element, the semiconductor light emitting element has high reliability against static electricity and the like, and the light emitting area of the semiconductor light emitting element is increased by disposing the protective element under the first bonding electrode. Since there is no influence, the light emission efficiency can be maintained without affecting the light emission efficiency of the semiconductor light emitting element.

  In the third aspect of the invention, the first bonding electrode connected to the p-type semiconductor layer for the light emitting element and the second bonding electrode connected to the n-type semiconductor layer for the light emitting element are provided. The protective element p-type semiconductor layer is connected to the second bonding electrode, the protective element n-type semiconductor layer is connected to the light-emitting element p-type semiconductor layer, and the protective element semiconductor A layer is formed below the second bonding electrode. A p-type semiconductor layer for a light-emitting element is connected to the first bonding electrode, an n-type semiconductor layer for a protective element is connected to the p-type semiconductor layer for the light-emitting element, and a second bonding electrode An n-type semiconductor layer for the light emitting element and a p-type semiconductor layer for the protection element are connected.

  That is, a semiconductor layer for a protective element (LED structure) connected in reverse parallel to a semiconductor layer for a light emitting element (LED structure) is incorporated in one semiconductor light emitting element, and the semiconductor layer for the protective element is second bonded. Provided under the electrode. Since the light emitting element and the protective element are included in one semiconductor light emitting element, the semiconductor light emitting element has high reliability against static electricity and the like, and the light emitting area of the semiconductor light emitting element is increased by disposing the protective element under the second bonding electrode. Since there is no influence, the light emission efficiency can be maintained without affecting the light emission efficiency of the semiconductor light emitting element.

  In the fourth invention, the n-type semiconductor layer, the active layer, and the p-type semiconductor layer for the first and second protective elements formed separately from the n-type semiconductor layer for the light emitting element are stacked on the substrate. The two separated semiconductor layers, a first bonding electrode connected to the p-type semiconductor layer for the light-emitting element, and a second bonding electrode connected to the n-type semiconductor layer for the light-emitting element. The n-type semiconductor layer for the first protection element is connected to the first bonding electrode, and the p-type semiconductor layer for the first protection element is connected to the n-type semiconductor layer for the second protection element. The p-type semiconductor layer for the second protection element is connected to the second bonding electrode, and the semiconductor layer for the first protection element is formed below the first bonding electrode. A semiconductor layer for the second protection element is formed below the second bonding electrode.

  That is, two semiconductor layers for protection elements (LED structure) connected in reverse parallel to the semiconductor layer for light emitting elements (LED structure) are built in one semiconductor light emitting element, and the semiconductor layer for protection element is provided. Each is provided below the first bonding electrode and the second bonding electrode. Thereby, since the light emitting element and the two protective elements connected in series are included in one semiconductor light emitting element, it is possible to have high reliability against static electricity and to increase the reverse withstand voltage. Further, by disposing the protective elements under the two bonding electrodes, respectively, the light emitting area of the semiconductor light emitting element is not affected, so that the light emitting efficiency can be maintained without affecting the light emitting efficiency of the semiconductor light emitting element.

  In the fifth invention, a light emitting device accommodates the above-described semiconductor light emitting element. Accordingly, it is possible to provide a light emitting device that can be protected from static electricity and overvoltage, and that can reduce the number of components, save space, or reduce cost.

  In the sixth invention, the seventh invention, the eighth invention, and the ninth invention, by providing the above light emitting device, it can be protected from static electricity and overvoltage, and the number of parts can be reduced, space saving or A lighting device, a display device, a signal lamp, or a road information device that can reduce costs can be provided.

  According to the present invention, since the semiconductor layer for the protective element is included in one semiconductor light emitting element, it is not necessary to connect the protective element to the outside of the semiconductor light emitting element, and the semiconductor has high reliability against static electricity or overvoltage. A light emitting element can be realized. Further, since there is no need to connect a protective element outside the semiconductor light emitting element, it is possible to reduce the number of parts, save space, or reduce the cost. Furthermore, since the semiconductor layer for the protective element is provided under the bonding electrode, the light emitting area of the semiconductor light emitting element is not affected, so that the light emitting efficiency can be maintained without affecting the light emitting efficiency of the semiconductor light emitting element.

FIG. 3 is a schematic diagram illustrating an example of a planar structure of the semiconductor light emitting element of the first embodiment. FIG. 3 is a cross-sectional view showing an example of a cross-sectional structure of the semiconductor light emitting element of the first embodiment. FIG. 3 is a circuit diagram of the semiconductor light emitting element of the first embodiment. FIG. 6 is an explanatory diagram showing a manufacturing process of the semiconductor light-emitting element of the first embodiment. FIG. 6 is an explanatory diagram showing a manufacturing process of the semiconductor light-emitting element of the first embodiment. FIG. 6 is a schematic diagram illustrating an example of a planar structure of a semiconductor light emitting element according to a second embodiment. FIG. 5 is a cross-sectional view showing an example of a cross-sectional structure of a semiconductor light emitting element in a second embodiment. FIG. 10 is an explanatory diagram showing a manufacturing process of the semiconductor light-emitting element of the second embodiment. FIG. 10 is an explanatory diagram showing a manufacturing process of the semiconductor light-emitting element of the second embodiment. FIG. 6 is a schematic diagram illustrating an example of a planar structure of a semiconductor light emitting element according to a third embodiment. FIG. 6 is a cross-sectional view showing an example of a cross-sectional structure of a semiconductor light emitting element in a third embodiment. FIG. 6 is a circuit diagram of a semiconductor light emitting element in a third embodiment. FIG. 10 is an explanatory diagram showing a manufacturing process of the semiconductor light emitting element of the third embodiment. FIG. 10 is an explanatory diagram showing a manufacturing process of the semiconductor light emitting element of the third embodiment. It is a schematic diagram which shows an example of a structure of the light-emitting device of this Embodiment.

(Embodiment 1)
Hereinafter, the present invention will be described with reference to the drawings illustrating embodiments thereof. FIG. 1 is a schematic view showing an example of a planar structure of the semiconductor light emitting device 100 of the first embodiment, and FIG. 2 is a cross sectional view showing an example of a cross sectional structure of the semiconductor light emitting device 100 of the first embodiment. FIG. 3 is a circuit diagram of the semiconductor light emitting element 100 of the first embodiment.

  The semiconductor light emitting device 100 of the present embodiment (hereinafter also referred to as “light emitting device”) is obtained by separating a light emitting device by cutting a wafer on which a plurality of light emitting devices are formed into a rectangular parallelepiped shape with a predetermined dimension. For example, an LED chip. In FIG. 2, 1 is a sapphire substrate. The sapphire substrate 1 (hereinafter referred to as “substrate”) has a rectangular shape in plan view, and the vertical and horizontal dimensions are, for example, about 0.35 mm, but the dimensions are not limited thereto.

  As shown in FIGS. 1 and 2, the light emitting element 100 includes a semiconductor layer (a semiconductor layer (a non-illustrated) n-type semiconductor layer 2, and a p-type semiconductor layer 3) stacked on a rectangular substrate 1. LED structure) is formed. A first bonding electrode 81 and a second bonding electrode 82 which are separated by an appropriate length are provided on the surface of the light emitting element 100. The bonding electrodes 81 and 82 are electrodes for bonding a wire for connecting the light emitting element 100 and an external circuit (such as an external electrode or a lead wire).

  Below the first bonding electrode 81, an n-type semiconductor layer 12 for a protective element is formed separately from the n-type semiconductor layer 2 for the light emitting element. An active layer (not shown) and a p-type semiconductor layer 13 are stacked on the n-type semiconductor layer 12 for the protection element. The n-type semiconductor layer 12, the active layer (not shown), and the p-type semiconductor layer 13 form a semiconductor layer (LED structure) for a protection element. Note that “for a light-emitting element” in this embodiment does not refer to the entire semiconductor light-emitting element but is used to indicate a light-emitting portion.

  As shown in FIG. 1, the p-type semiconductor layer 3 for the light emitting element becomes a light emitting surface of the light emitting element 100. That is, most of the area excluding the bonding electrodes 81 and 82 is a light emitting area. The shape of the bonding electrodes 81 and 82 is an example, and is not limited to the example of FIG.

  As shown in FIG. 2, an AlN buffer layer (not shown), an undoped GaN layer (not shown) having a thickness of about 2 μm, an n-type semiconductor layer 2, an active layer (not shown), and a p-type semiconductor layer are formed on a substrate 1. 3 are stacked in this order. The n-type semiconductor layer 2 includes, for example, an n-GaN (gallium nitride) layer having a thickness of about 2 μm, an n-AlGaInN cladding layer, and the like. The active layer is composed of a GaN / InGaN-MQW (Multi-quantum Well) type active layer or the like. The p-type semiconductor layer 3 includes a p-AlGaInN layer, a p-GaN layer of about 0.3 μm, a p-InGaN layer as a contact layer, and the like. Thus, a compound semiconductor layer is formed to form an LED structure as a semiconductor layer for a light emitting element. In addition, the structure which does not form an undoped GaN layer may be sufficient.

  A current diffusion layer 4 is formed on the upper surface of the p-type semiconductor layer 3. The current diffusion layer 4 is, for example, an ITO film (indium tin oxide film) that is a conductive transparent film. The p-type semiconductor layer 3 is connected to the first bonding electrode 81 through the current diffusion layer 4.

  An n ohmic electrode 6 is formed on the surface of the n-type semiconductor layer 2 exposed by removing a part of the p-type semiconductor layer 3 and the active layer of the semiconductor layer for the light emitting element by etching or the like. The n ohmic electrode 6 is electrically connected to the second bonding electrode 82. As a result, the n-type semiconductor layer 2 for the light emitting element is connected to the second bonding electrode 82.

  The n-ohmic electrode 6 is formed by, for example, forming a V / Au / Al / Ni / Au film by vacuum deposition, performing patterning by a lift-off method, and heating to about 500 ° C. in a mixed atmosphere of nitrogen and oxygen. Can do. The n ohmic electrode 6 is a portion that performs electrical junction with the n-type semiconductor layer 2.

  The bonding electrodes 81 and 82 can be formed, for example, by depositing Ti / Au by vacuum deposition. Since Ti / Au is used as the material of the bonding electrodes 81 and 82, the mechanical strength is excellent and bonding is easy, and it is difficult to peel off. Note that a metal such as Ni / Au can also be used as the material of the bonding electrodes 81 and 82.

  Further, the semiconductor layer for the protective element can be formed in the same manner as the semiconductor layer for the light emitting element. That is, an AlN buffer layer (not shown), an undoped GaN layer (not shown) having a thickness of about 2 μm, an n-type semiconductor layer 12 and an active layer (not shown) are separated from the n-type semiconductor layer 2 on the substrate 1. The p-type semiconductor layer 13 is laminated in this order to form a protective element semiconductor layer (LED structure). The n-type semiconductor layer 12 includes, for example, an n-GaN (gallium nitride) layer having a thickness of about 2 μm, an n-AlGaInN cladding layer, and the like. The active layer is composed of a GaN / InGaN-MQW (Multi-quantum Well) type active layer or the like. The p-type semiconductor layer 13 includes a p-AlGaInN layer, a p-GaN layer of about 0.3 μm, a p-InGaN layer as a contact layer, and the like. Thus, a compound semiconductor layer is formed to form an LED structure as a semiconductor layer for a protection element.

  A current diffusion layer 4 is formed on the upper surface of the p-type semiconductor layer 13. The p-type semiconductor layer 13 is connected to the n-type semiconductor layer 2 by the n-ohmic electrode 6 through the current diffusion layer 4.

  An n-ohmic electrode 6 is formed on the surface of the n-type semiconductor layer 12 exposed by removing a part of the p-type semiconductor layer 13 and the active layer of the semiconductor layer for the protective element by etching or the like. The n ohmic electrode 6 is electrically connected to the first bonding electrode 81. As a result, the n-type semiconductor layer 12 for the protection element is connected to the first bonding electrode 81.

Further, the semiconductor layer for the light emitting element and the semiconductor layer for the protective element are electrically insulated by the SiO ₂ films 5 and 7. Further, for example, a SiO ₂ film 7 is formed as a protective film on the side surface and the upper surface of the n-type semiconductor layer 2, the p-type semiconductor layer 3, the current diffusion layer 4, and the like that are not electrically connected. It is.

  As described above, a semiconductor in which an n-type semiconductor layer 12 for a protection element, an active layer (not shown), and a p-type semiconductor layer 13 formed on the substrate 1 separately from the n-type semiconductor layer 2 for a light emitting element are stacked. The semiconductor layer for the protective element is formed below the bonding electrode 81 that is electrically connected to the p-type semiconductor layer 3 for the light emitting element. Since a single light emitting element 100 includes a semiconductor layer for a protective element, it is not necessary to connect a protective element to the outside of the light emitting element 100, and a light emitting element (LED chip) having high reliability against static electricity or overvoltage is provided. Can be realized. Further, since it is not necessary to connect a protective element to the outside of the light emitting element 100, it is possible to reduce the number of parts, save space, or reduce cost. Further, by providing the semiconductor layer for the protective element under the bonding electrode, the light emitting area of the light emitting element 100 is not affected, and thus the light emitting efficiency can be maintained without affecting the light emitting efficiency of the light emitting element 100.

  The light emitting element 100 includes a first bonding electrode 81 electrically connected to the p-type semiconductor layer 3 for the light emitting element, and a second bonding electrode electrically connected to the n-type semiconductor layer 2 for the light emitting element. And a bonding electrode 82. The n-type semiconductor layer 12 for the protective element is electrically connected to the first bonding electrode 81, and the p-type semiconductor layer 13 for the protective element is electrically connected to the n-type semiconductor layer 2 for the light emitting element. A semiconductor layer for protection element is formed below the first bonding electrode 81.

  The p-type semiconductor layer 3 for the light emitting element and the n-type semiconductor layer 12 for the protective element are electrically connected to the first bonding electrode 81, and the n-type for the light emitting element is connected to the second bonding electrode 82. The semiconductor layer 2 is electrically connected, and the p-type semiconductor layer 13 for the protection element is electrically connected to the n-type semiconductor layer 2 for the light emitting element.

  That is, as shown in FIG. 3, the light emitting element 100 incorporates a protection element LED structure (LED2) connected in reverse parallel to the LED structure (LED1) for the light emitting element, and protects the light emitting element 100. A semiconductor layer for the element is provided under the first bonding electrode 81. Since the light emitting element 100 includes the light emitting element and the protective element, the light emitting element 100 has high reliability against static electricity and the like, and the light emitting area of the light emitting element 100 is provided by disposing the protective element under the first bonding electrode 81. Thus, the light emission efficiency of the light emitting element 100 is not affected and the light emission efficiency can be maintained.

  Next, a method for manufacturing the semiconductor light emitting device 100 of the first embodiment will be described. 4 and 5 are explanatory views showing the manufacturing steps of the semiconductor light emitting device 100 of the first embodiment. As shown in FIG. 4A, an AlN buffer layer (not shown) is first grown on a substrate (sapphire substrate) 1 at about 400 ° C. by metal organic chemical vapor deposition (MO-CVD). Thereafter, an n-type semiconductor layer 2 including an undoped GaN layer of about 2 μm, an n-GaN layer of about 2 μm and an n-AlGaInN cladding layer, a GaN / InGaN-MQW type active layer (not shown), and p-AlGaInN An LED structure is generated in which a p-type semiconductor layer 3 composed of a layer, a p-GaN layer of about 0.3 μm, and a p-InGaN layer as a contact layer is formed in this order. While irradiating the substrate 1 taken out from the MO-CVD apparatus with ultraviolet rays, the substrate 1 is heated to about 400 ° C. to activate the p-type semiconductor layer 3.

  As shown in FIG. 4B, the p-type semiconductor layer 3 is removed and the n-type semiconductor layer 2 is exposed by photolithography and dry etching using the photoresist as a mask. At this time, a portion for electrically connecting the n-type semiconductor layer 2 and the second bonding electrode 82 is exposed. In addition, the n-type semiconductor layer 2 is exposed below the first bonding electrode 81 where the semiconductor layer for the protective element is to be formed. Thereby, the p-type semiconductor layer 13 for the protection element is formed. Note that the etching depth is, for example, 400 nm.

  As shown in FIG. 4C, a transparent current diffusion layer 4 of an ITO film (indium tin oxide film) is formed to a thickness of about 400 nm by a film forming method such as vacuum evaporation or sputtering, and patterned by a lift-off method. Thereby, the light emitting surface of the light emitting element 100 and the current diffusion layer 4 of the protection element are formed.

  As shown in FIG. 4D, in order to electrically separate the semiconductor layer for the light emitting element and the semiconductor layer for the protective element of the light emitting element 100, the semiconductor layer for the light emitting element and the protective element are formed by photolithography and dry etching. Etching is performed on the semiconductor layer between the semiconductor layers for use until the substrate 1 is exposed. Thereby, the n-type semiconductor layer 12 for the protective element separated from the semiconductor layer for the light emitting element is formed.

As shown in FIG. 5E, a SiO ₂ film 5 is formed on the entire surface by plasma CVD, and a portion other than the first bonding electrode 81 of the light emitting element 100, a semiconductor layer for a protective element, and a light emitting element for dilute hydrofluoric acid. The SiO ₂ film 5 at the connection portion between the semiconductor layer and the connection portion between the semiconductor layer for the protective element and the first bonding electrode 81 is removed. As a result, the SiO ₂ film 5 is formed on the upper surface and side surfaces of the protective element semiconductor layer except for the electrically connected portions.

  As shown in FIG. 5F, a V / Au / Al / Ni / Au film is formed by vacuum deposition, and patterning is performed by a lift-off method to form an n ohmic electrode 6. The portion where the film is left, that is, the portion where the n-ohmic electrode 6 is formed is an ohmic junction provided in the portion where the n-type semiconductor layers 2 and 12 are exposed, the n-type semiconductor layer 2 and the current diffusion layer 4 for the protection element. Wiring part. After patterning, the n ohmic electrode 6 and the current diffusion layer 4 are annealed simultaneously by heating to about 500 ° C. in a tube furnace in a mixed atmosphere of nitrogen and oxygen.

As shown in FIG. 5G, the SiO ₂ film 7 is formed on the entire surface by plasma CVD, and the portions where the bonding electrodes 81 and 82 are provided by diluted hydrofluoric acid, the ohmic electrode provided on the n-type semiconductor layer 12 for the protective element 6 and the first bonding electrode 81 and the SiO ₂ film 7 in the element isolation portion are removed.

  As shown in FIG. 5H, a Ti / Au film is formed by vacuum deposition and patterned by lift-off to form bonding electrodes 81 and 82 and a wiring metal (not shown). As a result, an LED wafer in which a plurality of LED chips in which two LED structures (LEDs 1 and 2) are connected in reverse parallel is formed in one package (LED chip) is completed.

  Thereafter, element (LED chip) separation is performed by laser scribing to complete the light emitting element 100 (LED chip).

  In Embodiment 1, the semiconductor layer for the protective element is formed below the first bonding electrode 81 electrically connected to the p-type semiconductor layer 3 for the light emitting element. However, the present invention is not limited to this. . For example, a semiconductor layer for a protective element can be formed below the second bonding electrode 82 that is electrically connected to the n-type semiconductor layer 2 for the light emitting element.

(Embodiment 2)
FIG. 6 is a schematic diagram showing an example of a planar structure of the semiconductor light emitting device 110 according to the second embodiment. FIG. 7 is a cross sectional view showing an example of a sectional structure of the semiconductor light emitting device 110 according to the second embodiment. The difference from the first embodiment is that a semiconductor layer (LED structure) for a protective element is provided below the second bonding electrode 82. The same parts as those in the first embodiment are denoted by the same reference numerals.

  As shown in FIGS. 6 and 7, an n-type semiconductor layer 12 for a protective element is formed below the second bonding electrode 82 so as to be separated from the n-type semiconductor layer 2 for a light-emitting element. An active layer (not shown) and a p-type semiconductor layer 13 are stacked on the n-type semiconductor layer 12 for the protection element. The n-type semiconductor layer 12, the active layer (not shown), and the p-type semiconductor layer 13 form a semiconductor layer (LED structure) for a protection element.

  A protective layer n-type semiconductor layer 12 formed separately from the light-emitting element n-type semiconductor layer 2 on the substrate 1, a semiconductor layer in which an active layer (not shown) and a p-type semiconductor layer 13 are stacked, A protective element semiconductor layer is formed under the bonding electrode 82 electrically connected to the light emitting element n-type semiconductor layer 2. Since a light emitting element 110 includes a semiconductor layer for a protective element, it is not necessary to connect a protective element to the outside of the light emitting element 110, and a light emitting element (LED chip) having high reliability against static electricity or overvoltage is provided. Can be realized. In addition, since it is not necessary to connect a protective element to the outside of the light emitting element 110, it is possible to reduce the number of parts, save space, or reduce cost. Furthermore, by providing the semiconductor layer for the protective element under the bonding electrode, the light emitting area of the light emitting element 110 is not affected, so that the light emitting efficiency can be maintained without affecting the light emitting efficiency of the light emitting element 110.

  The light emitting element 110 includes a first bonding electrode 81 connected to the p-type semiconductor layer 3 for the light emitting element and a second bonding electrode 82 connected to the n-type semiconductor layer 2 for the light emitting element. . The p-type semiconductor layer 13 for the protective element is connected to the second bonding electrode 82, the n-type semiconductor layer 12 for the protective element is connected to the p-type semiconductor layer 3 for the light emitting element, and protection A semiconductor layer for the element is formed below the second bonding electrode 82. The first bonding electrode 81 is connected to the p-type semiconductor layer 3 for the light-emitting element, the n-type semiconductor layer 12 for the protective element is connected to the p-type semiconductor layer 3 for the light-emitting element, and the second bonding The electrode 82 is connected to the n-type semiconductor layer 2 for the light emitting element and the p-type semiconductor layer 13 for the protective element.

  That is, as shown in FIG. 3, the light emitting element 110 incorporates a protection element LED structure (LED2) connected in reverse parallel to the light emitting element LED structure (LED1) in one light emitting element 110 and protects it. A semiconductor layer for the element is provided under the second bonding electrode 82. Since the light emitting element 110 and the protective element are included in one light emitting element 110, the light emitting element 110 has high reliability against static electricity and the like, and the light emitting area of the light emitting element 110 is provided by disposing the protective element under the second bonding electrode 82. Thus, the light emission efficiency of the light emitting element 110 is not affected and the light emission efficiency can be maintained.

  Next, a method for manufacturing the semiconductor light emitting device 110 of the second embodiment will be described. 8 and 9 are explanatory views showing manufacturing steps of the semiconductor light emitting device 110 of the second embodiment. As shown in FIG. 8A, an AlN buffer layer (not shown) is first grown at about 400 ° C. on a substrate (sapphire substrate) 1 by metal organic chemical vapor deposition (MO-CVD). Thereafter, an n-type semiconductor layer 2 including an undoped GaN layer of about 2 μm, an n-GaN layer of about 2 μm and an n-AlGaInN cladding layer, a GaN / InGaN-MQW type active layer (not shown), and p-AlGaInN An LED structure is generated in which a p-type semiconductor layer 3 composed of a layer, a p-GaN layer of about 0.3 μm, and a p-InGaN layer as a contact layer is formed in this order. While irradiating the substrate 1 taken out from the MO-CVD apparatus with ultraviolet rays, the substrate 1 is heated to about 400 ° C. to activate the p-type semiconductor layer 3.

  As shown in FIG. 8B, the p-type semiconductor layer 3 is removed and the n-type semiconductor layer 2 is exposed by photolithography and dry etching using the photoresist as a mask. At this time, a portion for electrically connecting the n-type semiconductor layer 2 and the second bonding electrode 82 is exposed. In addition, the n-type semiconductor layer 2 is exposed below the second bonding electrode 82 where the semiconductor layer for the protective element is to be formed. Thereby, the p-type semiconductor layer 13 for the protection element is formed. Note that the etching depth is, for example, 400 nm.

  As shown in FIG. 8C, a transparent current diffusion layer 4 of an ITO film (indium tin oxide film) is formed to a thickness of about 400 nm by a film forming method such as vacuum evaporation or sputtering, and patterned by a lift-off method. Thereby, the light emitting surface of the light emitting element 110 and the current diffusion layer 4 of the protection element are formed.

  As shown in FIG. 8D, in order to electrically isolate the semiconductor layer for the light emitting element and the semiconductor layer for the protective element of the light emitting element 110, the semiconductor layer for the light emitting element and the protective element are formed by photolithography and dry etching. Etching is performed on the semiconductor layer between the semiconductor layers for use until the substrate 1 is exposed. Thereby, the n-type semiconductor layer 12 for the protective element separated from the semiconductor layer for the light emitting element is formed.

As shown in FIG. 9E, a SiO ₂ film 5 is formed on the entire surface by plasma CVD, and a portion other than the second bonding electrode 82 of the light emitting element 110, a semiconductor layer for a protective element, and a light emitting element for dilute hydrofluoric acid. The SiO ₂ film 5 at the connection portion between the semiconductor layer and the connection portion between the protective element semiconductor layer and the second bonding electrode 82 is removed. As a result, the SiO ₂ film 5 is formed on the upper surface and side surfaces of the protective element semiconductor layer except for the electrically connected portions.

  As shown in FIG. 9F, a V / Au / Al / Ni / Au film is formed by vacuum deposition, and patterning is performed by a lift-off method to form an n ohmic electrode 6. The part where the film is left, that is, the part where the n-ohmic electrode 6 is formed is an ohmic junction provided in the part where the n-type semiconductor layers 2 and 12 are exposed, the n-type semiconductor layer 12 for the protection element, and the current diffusion for the light-emitting element. This is a wiring portion with the layer 4. After patterning, the n ohmic electrode 6 and the current diffusion layer 4 are annealed simultaneously by heating to about 500 ° C. in a tube furnace in a mixed atmosphere of nitrogen and oxygen.

As shown in FIG. 9G, the SiO ₂ film 7 is formed on the entire surface by plasma CVD, and the portions where the bonding electrodes 81 and 82 are provided and the SiO ₂ film 7 in the element isolation portion are removed by diluted hydrofluoric acid.

  As shown in FIG. 9H, a Ti / Au film is formed by vacuum deposition and patterned by lift-off to form bonding electrodes 81 and 82 and a wiring metal (not shown). As a result, an LED wafer in which a plurality of LED chips in which two LED structures (LEDs 1 and 2) are connected in reverse parallel is formed in one package (LED chip) is completed.

  Thereafter, element (LED chip) separation is performed by laser scribing to complete the light emitting element 110 (LED chip).

  In the first and second embodiments, one semiconductor layer (LED structure) for a protective element is formed and provided below the bonding electrode. However, the present invention is not limited to this. For example, two semiconductor layers (LED structures) for protective elements can be formed and disposed below each bonding electrode.

(Embodiment 3)
FIG. 10 is a schematic view showing an example of a planar structure of the semiconductor light emitting device 120 of the third embodiment, and FIG. 11 is a cross sectional view showing an example of a sectional structure of the semiconductor light emitting device 120 of the third embodiment. These are the circuit diagrams of the semiconductor light-emitting device 120 of Embodiment 3. FIG. The difference from the first and second embodiments is that a protective element semiconductor layer (LED structure) is provided below the first and second bonding electrodes 81 and 82. The same parts as those in the first embodiment are denoted by the same reference numerals.

  As shown in FIGS. 10 and 11, below the first bonding electrode 81, an n-type semiconductor layer 12 for a protection element is formed separately from the n-type semiconductor layer 2 for the light-emitting element. An active layer (not shown) and a p-type semiconductor layer 13 are stacked on the n-type semiconductor layer 12 for the protection element. The n-type semiconductor layer 12, the active layer (not shown), and the p-type semiconductor layer 13 form a semiconductor layer (LED structure) for a protection element.

  In addition, below the second bonding electrode 82, an n-type semiconductor layer 22 for a protective element is formed separately from the n-type semiconductor layer 2 for the light-emitting element. An active layer (not shown) and a p-type semiconductor layer 23 are stacked on the n-type semiconductor layer 22 for the protection element. The n-type semiconductor layer 22, the active layer (not shown), and the p-type semiconductor layer 23 form a semiconductor layer (LED structure) for a protection element.

  A semiconductor layer in which an n-type semiconductor layer 12 for a first protective element, an active layer, and a p-type semiconductor layer 13 formed on the substrate 1 separately from the n-type semiconductor layer 2 for a light emitting element are stacked; Two separated semiconductor layers of a semiconductor layer in which an n-type semiconductor layer 22 for a protective element, an active layer and a p-type semiconductor layer 23 are stacked, and a first bonding connected to the p-type semiconductor layer 3 for a light-emitting element The electrode 81 and the 2nd bonding electrode 82 connected to the n-type semiconductor layer 2 for light emitting elements are provided. The n-type semiconductor layer 12 for the first protection element is connected to the first bonding electrode 81, and the p-type semiconductor layer 13 for the first protection element is connected to the n-type semiconductor for the second protection element. The p-type semiconductor layer 22 for the second protection element is connected to the second bonding electrode 82, and the semiconductor layer for the first protection element is connected to the first bonding electrode 81. A semiconductor layer for the second protection element is formed on the lower side of the second bonding electrode 82.

  That is, as shown in FIG. 12, the light emitting element 120 includes two LED structures for protection elements (LED2, LED3) connected in reverse parallel to the LED structure for light emitting elements (LED1). And a protective element semiconductor layer is provided under the first bonding electrode 81 and the second bonding electrode 82, respectively.

  Accordingly, since one light emitting element 120 includes the light emitting element and two protective elements connected in series, it has high reliability against static electricity and the like, and can increase the reverse withstand voltage. For example, when the number of protective elements is one, the reverse withstand voltage is about 2.5 V to 3 V, but by providing two protective elements in series, the withstand voltage can be increased to about 5 V to 6 V. Further, by disposing the protective elements under the two bonding electrodes 81 and 82, respectively, the light emitting area of the light emitting element 120 is not affected, so that the light emitting efficiency of the light emitting element 120 is not affected and the light emitting efficiency is maintained. Can do.

  In Embodiment 3 described above, two protection elements are provided in series. However, the present invention is not limited to this, and each of the two protection elements is provided in reverse parallel to the LED structure for the light emitting element. A configuration connected in parallel may be employed. In this case, even when one of the protection elements fails to open, the other protection element can perform the protection function, so that the reliability of the light emitting element is further improved.

  Next, a method for manufacturing the semiconductor light emitting device 120 of the third embodiment will be described. 13 and 14 are explanatory views showing the manufacturing process of the semiconductor light emitting device 120 of the third embodiment. As shown in FIG. 13A, an AlN buffer layer (not shown) is first grown at about 400 ° C. on a substrate (sapphire substrate) 1 by metal organic chemical vapor deposition (MO-CVD). Thereafter, an n-type semiconductor layer 2 including an undoped GaN layer of about 2 μm, an n-GaN layer of about 2 μm and an n-AlGaInN cladding layer, a GaN / InGaN-MQW type active layer (not shown), and p-AlGaInN An LED structure is generated in which a p-type semiconductor layer 3 composed of a layer, a p-GaN layer of about 0.3 μm, and a p-InGaN layer as a contact layer is formed in this order. While irradiating the substrate 1 taken out from the MO-CVD apparatus with ultraviolet rays, the substrate 1 is heated to about 400 ° C. to activate the p-type semiconductor layer 3.

  As shown in FIG. 13B, the p-type semiconductor layer 3 is removed and the n-type semiconductor layer 2 is exposed by photolithography and dry etching using the photoresist as a mask. At this time, the n-type semiconductor layer 2 is exposed below the first bonding electrode 81 and where the semiconductor layer for the protective element is to be formed. In addition, the n-type semiconductor layer 2 is exposed below the second bonding electrode 82 where the semiconductor layer for the protective element is to be formed. Thereby, the p-type semiconductor layers 13 and 23 for the protection elements are formed. Note that the etching depth is, for example, 400 nm.

  As shown in FIG. 13C, a transparent current diffusion layer 4 of an ITO film (indium tin oxide film) is formed to a thickness of about 400 nm by a film forming method such as vacuum evaporation or sputtering, and patterned by a lift-off method. Thereby, the light emission surface of the light emitting element 120 and the current diffusion layer 4 of the protection element are formed.

  As shown in FIG. 13D, in order to electrically separate the semiconductor layer for the light emitting element and the semiconductor layer for the protective element of the light emitting element 120, the semiconductor layer for the light emitting element and the protective element are formed by photolithography and dry etching. Etching is performed on the semiconductor layer between the semiconductor layers for use until the substrate 1 is exposed. Thereby, the n-type semiconductor layers 12 and 22 for the protection element separated from the semiconductor layer for the light emitting element are formed.

As shown in FIG. 14E, the SiO ₂ film 5 is formed on the entire surface by plasma CVD, and the connection between the protective element semiconductor layer of the light emitting element 120 and the semiconductor layer for the light emitting element, and protection by diluted hydrofluoric acid. The SiO ₂ film 5 at the connecting portion between the element semiconductor layer and the first and second bonding electrodes 81 and 82 is removed. Thereby, the part except the part electrically connected among the upper surface and side surface of the semiconductor layer for protection elements, and the connection part of the semiconductor layer for light emitting elements, and the 1st and 2nd bonding electrodes 81 and 82 The SiO ₂ film 5 is formed in the portion excluding.

  As shown in FIG. 14F, a V / Au / Al / Ni / Au film is formed by vacuum deposition, and patterning is performed by a lift-off method to form an n ohmic electrode 6. The portion where the film is left, that is, the portion where the n-ohmic electrode 6 is formed is an ohmic junction provided in the portion where the n-type semiconductor layers 2, 12 and 22 are exposed, the n-type semiconductor layer 22 for the second protection element, and the second 1 is a wiring portion with the current diffusion layer 4 for one protection element. After patterning, the n ohmic electrode 6 and the current diffusion layer 4 are annealed simultaneously by heating to about 500 ° C. in a tube furnace in a mixed atmosphere of nitrogen and oxygen.

As shown in FIG. 14G, the SiO ₂ film 7 is formed on the entire surface by plasma CVD, the bonding electrodes 81 and 82 are provided by diluted hydrofluoric acid, and the ohmic electrode provided on the n-type semiconductor layer 12 for the protective element. 6 and the first bonding electrode 81 and the SiO ₂ film 7 in the element isolation portion are removed.

  As shown in FIG. 14H, a Ti / Au film is formed by vacuum deposition, and patterning is performed by lift-off to form bonding electrodes 81 and 82 and a wiring metal (not shown). As a result, a plurality of LED chips in which LED structures (LED2, 3) for protective elements connected in series are connected in reverse parallel to an LED structure (LED1) for one light emitting element in one package (LED chip) are formed. The completed LED wafer is completed.

  Thereafter, the element (LED chip) is separated by laser scribing to complete the light emitting element 120 (LED chip).

  FIG. 15 is a schematic diagram illustrating an example of the configuration of the light-emitting device 200 of the present embodiment. The light-emitting device 200 is a light-emitting diode, and includes a housing portion that houses any one of the above-described semiconductor light-emitting elements 100, 110, and 120 and any one of the semiconductor light-emitting elements 100, 110, and 120.

  As shown in FIG. 15, the light emitting device (light emitting diode) 200 includes lead frames 201 and 202, and a recess 201 a as an accommodating portion is provided at one end of the lead frame 201. A semiconductor light emitting element (LED chip) 100 is bonded and fixed to the bottom of the recess 201a by die bonding.

  One bonding electrode of the LED chip 100 is wire-bonded to the lead frame 201 by a wire 204, and the other bonding electrode is wire-bonded to the lead frame 202 by a wire 204. The recess 201a is filled with a translucent resin to form a cover 203 that covers the LED chip 100. In addition, the fluorescent substance 205 according to the emission color of the LED chip 100 can also be contained in the coating | coated part 203. FIG.

  The end portions of the lead frames 201 and 202 on which the covering portion 203 is formed are housed in a lens 206 having a convex end portion. The lens 206 is formed of a translucent resin such as an epoxy resin.

  The light emitting device (light emitting diode) 200 accommodates the semiconductor light emitting element 100 described above. Accordingly, it is possible to provide a light-emitting device that can protect against static electricity and overvoltage, and can reduce the number of components, save space, or reduce costs because an external resistor or protection element is unnecessary. it can. Further, there is almost no influence of a decrease in luminous efficiency due to the built-in protective element.

  In addition, a circuit board on which a large number of the above-described light emitting diodes 200 are mounted, and a power supply unit that drives a predetermined voltage to the light emitting diodes 200 in order to obtain a required brightness include a lighting device, a display device, a signal lamp, or a road information device. It can also be incorporated into such devices. For example, a lighting device, a display device, a signal lamp, or a road information device includes the light emitting device (light emitting diode) 200 of the present embodiment as a light source. Thus, it is possible to provide a lighting device, a display device, a signal lamp, or a road information device that can be protected from static electricity and overvoltage, and that can reduce the number of components, save space, downsize, or reduce cost. be able to.

1 substrate 2 n-type semiconductor layer (n-type semiconductor layer for light-emitting element)
3 p-type semiconductor layer (p-type semiconductor layer for light-emitting element)
12, 22 n-type semiconductor layer (n-type semiconductor layer for protection element)
13, 23 p-type semiconductor layer (p-type semiconductor layer for protective element)
81 Bonding electrode (first bonding electrode)
82 Bonding electrode (second bonding electrode)

Claims (9)

In a semiconductor light emitting device in which a semiconductor layer in which an n-type semiconductor layer, an active layer, and a p-type semiconductor layer for a light emitting device are stacked on a substrate is formed.
A semiconductor layer formed by laminating an n-type semiconductor layer, an active layer, and a p-type semiconductor layer for a protection element formed separately on the substrate from the n-type semiconductor layer;
A semiconductor light emitting element, wherein the protective element semiconductor layer is formed under a bonding electrode connected to the light emitting element n-type semiconductor layer or p-type semiconductor layer. A first bonding electrode connected to the p-type semiconductor layer for the light emitting element;
A second bonding electrode connected to the n-type semiconductor layer for the light emitting element,
An n-type semiconductor layer for the protective element is connected to the first bonding electrode;
A p-type semiconductor layer for the protective element is connected to an n-type semiconductor layer for the light-emitting element;
The semiconductor light emitting element according to claim 1, wherein a semiconductor layer for the protection element is formed below the first bonding electrode. A first bonding electrode connected to the p-type semiconductor layer for the light emitting element;
A second bonding electrode connected to the n-type semiconductor layer for the light emitting element,
A p-type semiconductor layer for the protective element is connected to the second bonding electrode;
An n-type semiconductor layer for the protective element is connected to a p-type semiconductor layer for the light-emitting element;
The semiconductor light emitting element according to claim 1, wherein a semiconductor layer for the protection element is formed below the second bonding electrode. Two separated semiconductor layers in which an n-type semiconductor layer for the first and second protection elements formed separately from the n-type semiconductor layer on the substrate, an active layer, and a p-type semiconductor layer are stacked;
A first bonding electrode connected to the p-type semiconductor layer for the light emitting element;
A second bonding electrode connected to the n-type semiconductor layer for the light emitting element,
An n-type semiconductor layer for the first protection element is connected to the first bonding electrode;
A p-type semiconductor layer for the first protection element is connected to an n-type semiconductor layer for the second protection element;
A p-type semiconductor layer for the second protection element is connected to the second bonding electrode;
A semiconductor layer for the first protection element is formed below the first bonding electrode;
2. The semiconductor light emitting element according to claim 1, wherein a semiconductor layer for the second protection element is formed below the second bonding electrode.   5. A light emitting device comprising: the semiconductor light emitting element according to claim 1; and a housing portion that houses the semiconductor light emitting element.   An illumination device comprising the light-emitting device according to claim 5.   A display device comprising the light-emitting device according to claim 5.   A signal lamp comprising the light emitting device according to claim 5.   A road information device comprising the light-emitting device according to claim 5.

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