Light-emitting device

Abstract

To provide a light-emitting device that reduces variation in color.SOLUTION: A light-emitting device using a group-III nitride semiconductor has first and second light-emitting regions different in emission wavelength. The first light-emitting region has a plurality of first regions. The second light-emitting region has a plurality of second regions. In plane patterns of the first and second light-emitting regions, a pattern including one or more of the first regions and one or more of the second regions is set as one unit in a prescribed direction, and the plurality of units are arranged. The plurality of first regions are electrically connected in parallel, and the plurality of second regions are electrically connected in parallel.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a light-emitting device. [Background technology]

[0002] Various light-emitting devices capable of full-color emission have been proposed. One known method for achieving full color emission is to stack three active layers, each emitting blue, green, and red light, in that order on the same substrate, with an intermediate layer inserted between the active layers.

[0003] The light-emitting device described in Patent Document 1 has an n-type layer, a first active layer, a first intermediate layer, a second active layer, a second intermediate layer, a third active layer, and a cap layer stacked on a substrate in this order from the substrate side, with a first recess extending from the surface of the cap layer to the second intermediate layer and a second recess extending from the surface of the cap layer to the first intermediate layer, a p-type layer extending continuously on the cap layer, the side and bottom surfaces of the first recess, and the side and bottom surfaces of the second recess, and a first p-electrode, a second p-electrode, and a third p-electrode are provided on the p-type layer in a region corresponding to the top of the cap layer, a region corresponding to the first recess, and a region corresponding to the second recess, respectively. The third active layer below the first p-electrode, the second active layer below the second p-electrode, and the first active layer below the third p-electrode each emit light. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 7283428 Summary of the Invention [Problem to be solved by the invention]

[0005] In the structure of Patent Document 1, the light-emitting region is divided into three in plan view, which can cause color variations depending on the viewing angle.

[0006] The present invention has been made in view of the above background, and aims to provide a light-emitting element with reduced color variation. [Means for solving the problem]

[0007] One aspect of the present invention is In a light-emitting device using a Group III nitride semiconductor, It has a first light-emitting region and a second light-emitting region that emit light at different wavelengths, the first light-emitting region has a plurality of first regions, the second light-emitting region has a plurality of second regions, the plane patterns of the first light-emitting region and the second light-emitting region are patterns in which a plurality of units, each unit including one or more of the first region and one or more of the second region, are arranged in a predetermined direction; In the light-emitting device, the plurality of first regions are electrically connected in parallel, and the plurality of second regions are electrically connected in parallel. [Effects of the Invention]

[0008] In the above embodiment, the planar pattern of the first and second light-emitting regions other than the device end portions is a pattern in which two or more of the first and second regions (at least one first region and at least one second region) are arranged in sequence in a direction parallel to a certain side of the rectangular element, and the units are periodically arranged in a direction parallel to the certain side of the rectangular element, with multiple first regions electrically connected in parallel and multiple second regions electrically connected in parallel. By configuring the planar patterns of the first and second light-emitting regions in this manner, the variation in light intensity of the first and second light-emitting regions due to angle is reduced. As a result, the variation in color due to the viewing angle of the light-emitting element can be suppressed.

[0009] As described above, according to the above aspect, it is possible to provide a light-emitting element with reduced color variation. [Brief explanation of the drawings]

[0010] [Figure 1] 2. FIG. 3 is a cross-sectional view showing the configuration of the light-emitting element according to the first embodiment, taken along line II in FIG. [Figure 2] FIG. 2 is a plan view showing an electrode pattern of the light-emitting element according to the first embodiment. [Figure 3] 2A to 2C are diagrams illustrating a manufacturing process of the light-emitting element according to the first embodiment. [Figure 4] 2A to 2C are diagrams illustrating a manufacturing process of the light-emitting element according to the first embodiment. [Figure 5] 2A to 2C are diagrams illustrating a manufacturing process of the light-emitting element according to the first embodiment. [Figure 6] 2A to 2C are diagrams illustrating a manufacturing process of the light-emitting element according to the first embodiment. [Figure 7] 2A to 2C are diagrams illustrating a manufacturing process of the light-emitting element according to the first embodiment. [Figure 8] 2A to 2C are diagrams illustrating a manufacturing process of the light-emitting element according to the first embodiment. [Figure 9] FIG. 10 is a plan view showing the configuration of a light emitting element in a first modified example of the first embodiment. [Figure 10] FIG. 10 is a plan view showing the configuration of a light-emitting element in a second modified example of the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] A light-emitting element using a Group III nitride semiconductor has a first light-emitting region and a second light-emitting region with different emission wavelengths, the first light-emitting region has a plurality of first regions, and the second light-emitting region has a plurality of second regions. The planar patterns of the first light-emitting region and the second light-emitting region are a pattern in which a plurality of units, each unit including one or more first regions and one or more second regions, are arranged in a predetermined direction, and the plurality of first regions are electrically connected in parallel, and the plurality of second regions are electrically connected in parallel.

[0012] In the light-emitting device, the planar patterns of the first and second regions may be stripes extending in a direction perpendicular to the predetermined direction, and the units may be periodically arranged in the predetermined direction. One unit may include one first region and one second region.

[0013] The light emitting element may be rectangular in plan view, and the predetermined direction may be a direction parallel to one side of the rectangular light emitting element.

[0014] The light-emitting element may further have a third light-emitting region having an emission wavelength different from that of the first light-emitting region and the second light-emitting region, and the third light-emitting region may have a plurality of third regions. The planar patterns of the first light-emitting region, the second light-emitting region, and the third light-emitting region may be a pattern in which a plurality of units, each unit including one or more first regions, one or more second regions, and one or more third regions, are arranged in a predetermined direction, and the plurality of third regions may be electrically connected in parallel.

[0015] In the light-emitting element, the planar patterns of the first region, the second region, and the third region may be stripes extending in a direction perpendicular to the predetermined direction, and the units may be periodically arranged in the predetermined direction. One unit may include one first region, one second region, and one third region. The light-emitting element may be rectangular in plan view, and the predetermined direction may be a direction parallel to one side of the rectangle of the light-emitting element.

[0016] In the light-emitting element, the first light-emitting region may emit red light, the second light-emitting region may emit green light, and the third light-emitting region may emit blue light, and the area of ​​the first light-emitting region may be larger than the areas of the second light-emitting region and the third light-emitting region, making it easier to adjust the color balance.

[0017] In the light emitting device, the first light emitting region may emit red light, the second light emitting region may emit green light, and the third light emitting region may emit blue light, and the width of the stripes in the first region may be 2 to 10 times the width of the stripes in the second region.

[0018] a first intermediate layer provided on the first active layer and including a group III nitride semiconductor; a second active layer provided on the first intermediate layer and having a bandgap energy different from that of the first active layer; a first trench having a depth reaching from the second active layer side to the first intermediate layer; a p-type layer provided on the second active layer and on a bottom surface of the first trench and including a p-type group III nitride semiconductor; a first p-side contact electrode provided on the p-type layer; and a second p-side contact electrode provided on the bottom surface of the first trench, wherein a region of the second active layer below the first p-side contact electrode is a first light-emitting region, and a region of the first active layer below the second p-side contact electrode is a second light-emitting region.

[0019] A light-emitting device comprising: a substrate; an n-type layer provided on the substrate and containing an n-type Group III nitride semiconductor; a first active layer provided on the n-type layer and having a predetermined band gap energy; a first intermediate layer provided on the first active layer and containing a Group III nitride semiconductor; a second active layer provided on the first intermediate layer and having a band gap energy different from that of the first active layer; a second intermediate layer provided on the second active layer and containing a Group III nitride semiconductor; a third active layer provided on the second intermediate layer and having a band gap energy different from that of the first active layer and the second active layer; a first groove having a depth reaching from the third active layer side to the second intermediate layer; The semiconductor device may have a second groove having a depth reaching from the active layer side to the first intermediate layer, a p-type layer including a p-type Group III nitride semiconductor provided on the third active layer, on a bottom surface of the first groove, and on a bottom surface of the second groove, a first p-side contact electrode provided on the p-type layer, a second p-side contact electrode provided on the bottom surface of the first groove, and a third p-side contact electrode provided on the bottom surface of the second groove, wherein a region of the third active layer below the first p-side contact electrode is a first light-emitting region, a region of the second active layer below the second p-side contact electrode is a second light-emitting region, and a region of the first active layer below the third p-side contact electrode is a third light-emitting region.

[0020] The light-emitting element may have a third groove having a depth reaching from the third active layer side to the n-type layer, and an n-side contact electrode provided on the bottom surface of the third groove, and the planar pattern of the third groove and the n-side contact electrode may be a rectangular ring-shaped pattern along the outer periphery of the element.

[0021] (Embodiment 1) 1. Overview of the Light-Emitting Device in Embodiment 1 FIG. 1 is a cross-sectional view showing the configuration of a light-emitting element in embodiment 1, taken perpendicular to the main surface of the substrate. FIG. 2 is a plan view showing the electrode pattern of the light-emitting element in embodiment 1. FIG. 1 is a cross-sectional view taken along line II in FIG. 2. The light-emitting element in embodiment 1 is a flip-chip type, and has red, green, and blue light-emitting regions in plan view. The light emissions of these light-emitting regions can be controlled independently. This makes it possible to achieve full color with a single chip. The red, green, and blue light-emitting regions are arranged periodically, and FIG. 1 shows a structure for two periods.

[0022] 2. Light-emitting element configuration As shown in FIG. 1, the light-emitting element in embodiment 1 has a substrate 10, an n-type layer 11, a first active layer 12, a first intermediate layer 13, a second active layer 14, a second intermediate layer 15, a third active layer 16, an electron blocking layer 17, a p-type layer 18, p-side contact electrodes 20A to 20C, p-side electrodes 21A to 21C, an n-side contact electrode 22, an n-side electrode 23, and an insulating film 24.

[0023] The substrate 10 is a growth substrate for growing a group III nitride semiconductor, such as sapphire, Si, GaN, or ScAlMgO4 (SAM).

[0024] The n-type layer 11 is an n-type semiconductor provided on the substrate 10 via a low-temperature buffer layer or a high-temperature buffer layer (not shown). However, the buffer layer may be provided as needed, and if the substrate is GaN, the buffer layer may not be provided. The n-type layer 11 is, for example, n-GaN, n-AlGaN, or n-InGaN. The Si concentration is, for example, 1×10 18~100×10 18 cm -3 is.

[0025] The first active layer 12 is a light emitting layer of SQW or MQW structure provided on the n-type layer 11. The emitted light wavelength is blue, 430 to 480 nm. The first active layer 12 has a structure in which barrier layers made of AlGaN and well layers made of InGaN are alternately stacked in 1 to 9 pairs, more preferably 1 to 7 pairs, and even more preferably 1 to 5 pairs.

[0026] An underlayer may be provided between the n-type layer 11 and the first active layer 12, if necessary. The underlayer is a semiconductor layer with a superlattice structure provided on the n-type layer 11, and serves to alleviate lattice distortion of the semiconductor layer formed on the underlayer. The underlayer is formed by alternately laminating III nitride semiconductor thin films with different compositions (for example, two of GaN, InGaN, and AlGaN), and the number of pairs is, for example, 3 to 30. The underlayer may be undoped or may contain 1×10 Si. 17 ~100×10 17 cm -3 Also, as long as the strain can be relaxed, the superlattice structure is not necessary.

[0027] An ESD layer may be provided between the n-type layer 11 and the underlayer. The ESD layer is a layer provided to improve electrostatic breakdown voltage. The ESD layer may be made of, for example, undoped or lightly Si-doped GaN, InGaN, or AlGaN.

[0028] The first intermediate layer 13 is a semiconductor layer provided on the first active layer 12. The first intermediate layer 13 is a layer provided to enable separate control of light emission from the first active layer 12 and light emission from the second active layer 14. The first intermediate layer 13 also serves to protect the first active layer 12 from etching damage when forming second grooves 31, which will be described later.

[0029] The first intermediate layer 13 has a structure in which an undoped intermediate layer and an n-type intermediate layer are laminated in this order from the first active layer 12 side. The undoped intermediate layer and the n-type intermediate layer may be made of the same material except for impurities. The reason for making the first intermediate layer 13 have such a two-layer structure will be explained later.

[0030] The material of the first intermediate layer 13 is a group III nitride semiconductor containing In, such as InGaN. The surfactant effect of In can suppress roughness on the surface of the first intermediate layer 13, improving surface flatness. It can also alleviate lattice distortion.

[0031] The In composition of the first intermediate layer 13 (the molar ratio of In to the total Group III metals of the Group III nitride semiconductor) may be set to have a band gap that does not absorb light emitted from the first active layer 12 and the second active layer 14. A preferred In composition is 10% or less, more preferably 5% or less, and even more preferably 2% or less. If the In composition is greater than 10%, it will cause the surface of the first intermediate layer 13 to become rough. The In content may be any value greater than 0%, and may be at a doping level (a level that does not form a mixed crystal). For example, if the In concentration is 1×10 14 cm -3 More than 1×10 22 cm -3 The following is GaN.

[0032] The non-doped intermediate layer of the first intermediate layer 13 is non-doped, and the n-type intermediate layer 13B is Si-doped. The Si concentration of the n-type intermediate layer is 1×10 17 ~1000×10 17 cm -3 It is preferable to set it to 10×10 17 ~100×10 17 cm -3 , and more preferably 20×10 17 ~80×10 17 cm -3 The n-type intermediate layer may be modulation doped with Si, or a part of the n-type intermediate layer may be an undoped region.

[0033] The thickness of the first intermediate layer 13 is preferably 20 to 150 nm. If it is thicker than 150 nm, the surface of the first intermediate layer 13 may become rough. If it is thinner than 20 nm, it may be difficult to control the depth of the second grooves 31 (described later) so that they are within the non-doped intermediate layer when they are formed. The thickness is more preferably 30 to 100 nm, and even more preferably 50 to 80 nm.

[0034] The thickness of the non-doped intermediate layer of first intermediate layer 13 is preferably 10 nm or more, in order to control the etching depth and avoid etching damage to first active layer 12. The thickness of the n-type intermediate layer of first intermediate layer 13 is preferably 10 nm or more, in order to independently control the light-emitting characteristics of each active layer.

[0035] The second active layer 14 is a layer provided on the first intermediate layer 13 and has a quantum well structure of SQW or MQW. The emission wavelength is green and is 510 to 570 nm. The quantum well structure is formed by alternately stacking 1 to 7 pairs of barrier layers made of GaN or AlGaN and well layers made of InGaN.

[0036] A strain relaxation layer may be provided between the first intermediate layer 13 and the second active layer 14. By providing the strain relaxation layer, the strain in the second active layer 14 stacked thereon can be relaxed, improving the crystal quality. The strain relaxation layer has an SQW structure or MQW structure in which a barrier layer and a well layer are stacked in order, and is a quantum well structure in which the thickness of the well layer is adjusted to be thin so as not to emit light. For example, light emission can be prevented by setting the thickness of the well layer to 1 nm or less. The barrier layer is made of AlGaN, and the well layer is made of InGaN. The wavelength corresponding to the band edge energy of the well layer of the strain relaxation layer needs to be shorter than the emission wavelength of the second active layer 14; for example, if the emission wavelength is 500 to 560 nm, it is 400 to 460 nm.

[0037] The second intermediate layer 15 is a semiconductor layer provided on the second active layer 14. The second intermediate layer 15 is provided for the same reason as the first intermediate layer 13, and is a layer provided to enable separate control of the light emission from the second active layer 14 and the light emission from the third active layer 16. The second intermediate layer 15 also serves to protect the second active layer 14 from etching damage when forming the first grooves 30 described below.

[0038] The second intermediate layer 15 has a structure in which an undoped intermediate layer and an n-type intermediate layer are stacked in this order from the second active layer 14 side. The undoped intermediate layer and the n-type intermediate layer have the same structures as the undoped intermediate layer and the n-type intermediate layer of the first intermediate layer 13. In other words, the undoped intermediate layer and the n-type intermediate layer of the second intermediate layer 15 are made of the same materials as the undoped intermediate layer and the n-type intermediate layer of the first intermediate layer 13 except for impurities, and the thickness ranges are also the same. The undoped intermediate layer of the second intermediate layer 15 is undoped, and the n-type intermediate layer is Si-doped. The Si concentration of the n-type intermediate layer of the second intermediate layer 15 is in the same range as the Si concentration of the n-type intermediate layer of the first intermediate layer 13, and may be the same concentration.

[0039] The third active layer 16 is a layer provided on the second intermediate layer 15, and has a quantum well structure of SQW or MQW. The emission wavelength is red, 590 to 700 nm. The quantum well structure is formed by alternately stacking 1 to 7 pairs of barrier layers made of InGaN and well layers made of InGaN. The number of pairs is more preferably 1 to 5, and even more preferably 1 to 3.

[0040] A strain relaxation layer may be provided between the second intermediate layer 15 and the third active layer 16. By providing the strain relaxation layer, it is possible to relieve the strain in the third active layer 16 laminated thereon, thereby improving the crystal quality. The strain relaxation layer has a structure in which, for example, a first strain relaxation layer and a second strain relaxation layer are laminated in this order from the second intermediate layer 15 side.

[0041] The first and second strain relaxation layers have the same structure as the strain relaxation layer between the first intermediate layer 13 and the second active layer 14. The wavelength corresponding to the band edge energy of the well layer of the first strain relaxation layer is, for example, 400 to 460 nm. The wavelength corresponding to the band edge energy of the well layer of the second strain relaxation layer is, for example, 510 to 570 nm.

[0042] The electron blocking layer 17 is a semiconductor layer provided on the third active layer 16. The electron blocking layer 17 is a layer that blocks electrons injected from the n-type layer 11 in order to confine them efficiently in the third active layer 16. The electron blocking layer 17 not only functions as an electron blocking layer but also as a protective layer that protects the active layer. The electron blocking layer 17 may be made of a material that has a wider band gap than the well layer of the third active layer 16, such as AlGaN, GaN, or InGaN. The thickness of the electron blocking layer 17 is preferably 2.5 to 50 nm, and more preferably 5 to 25 nm. The electron blocking layer 17 may be doped with an impurity, or may be doped with Mg. In this case, the Mg concentration should be 1×10 18 ~1000×10 18 cm -3 It is best to do so.

[0043] A portion of the surface of the electron blocking layer 17 is etched to form grooves, including a first groove 30 that extends from the electron blocking layer 17 to the second intermediate layer 15, a second groove 31 that extends to the first intermediate layer 13, and a third groove 32 that extends to the n-type layer 11. The planar pattern of the first groove 30 and the second groove 31 is striped, and is a pattern that matches the p-side contact electrodes 20A to 20C, which will be described later. The planar pattern of the third groove 32 is a square ring pattern that follows the outer periphery of the device.

[0044] The first groove 30 has a depth that reaches the undoped intermediate layer 15A of the second intermediate layer 15. By removing the n-type intermediate layer 15B of the second intermediate layer 15 below the p-side electrode 21B in this way, an n-type layer is prevented from being positioned above the second active layer 14, allowing the second active layer 14 to emit light. The second groove 31 also has a depth that reaches the undoped intermediate layer 13A of the first intermediate layer 13. For the same reason, by removing the n-type intermediate layer 13B of the first intermediate layer 13 below the p-side electrode 21C, an n-type layer is prevented from being positioned above the first active layer 12, allowing the first active layer 12 to emit light.

[0045] The p-type layer 18 is a semiconductor layer provided continuously in a film shape on the electron blocking layer 17, the side surfaces and bottom surfaces of the first groove 30, and the side surfaces and bottom surfaces of the second groove 31. Of the p-type layer 18, the region on the electron blocking layer 17 is referred to as region 18A, the region on the bottom surface of the first groove 30 (on the second intermediate layer 15) is referred to as region 18B, and the region on the bottom surface of the second groove 31 (on the first intermediate layer 13) is referred to as region 18C. Of the p-type layer 18, the region connecting the regions 18A and 18B is referred to as region 18D, the region connecting the regions 18B and 18C is referred to as region 18E, and the region connecting the regions 18C and 18A is referred to as region 18F. The p-type layer 18 is composed of, in order from the electron blocking layer 17 side, the second electron blocking layer, the first layer, and the second layer. It is also possible to physically separate the regions 18A to 18C by not forming the regions 18D to 18F or by removing them by etching.

[0046] The second electron blocking layer is provided on the electron blocking layer 17, on the non-doped intermediate layer 15A exposed at the bottom of the first groove 30, and on the non-doped intermediate layer 13A exposed at the bottom of the second groove 31, and is a layer that blocks electrons injected from the n-type layer 11 to efficiently confine them in the first active layer 12, the second active layer 14, and the third active layer 16.

[0047] The second electron blocking layer may be a single layer of GaN or AlGaN, or may have a structure in which two or more of AlGaN, GaN, and InGaN are stacked, or a structure in which only the composition ratios are changed. It may also have a superlattice structure. A superlattice structure can more efficiently block electrons. Examples of superlattice structures include a structure in which p-AlGaN and p-InGaN are stacked alternately, or a structure in which p-AlGaN and p-GaN are stacked alternately.

[0048] The thickness of the second electron blocking layer is preferably 5 to 50 nm, more preferably 5 to 25 nm. The second electron blocking layer is Mg-doped p-type. By making it p-type, holes can be efficiently injected into the active layer. It also provides a larger barrier against electrons, enhancing the electron blocking function. The second electron blocking layer may be undoped, but for the above reasons, it is preferably p-type by doping with Mg. The Mg concentration of the second electron blocking layer is 1×10 19 ~100×10 19 cm -3 It is best to do so.

[0049] The first layer is preferably p-GaN or p-InGaN. The thickness of the first layer is preferably 10 to 500 nm, more preferably 10 to 200 nm, and further preferably 10 to 100 nm. The Mg concentration of the first layer is 1×10 19 ~100×10 19 cm -3 The second layer is preferably p-GaN or p-InGaN. The thickness of the second layer is preferably 2 to 50 nm, more preferably 4 to 20 nm, and further preferably 6 to 10 nm. The Mg concentration of the second layer is 1×10 20 ~100×10 20 cm -3 It is best to do so.

[0050] P-side contact electrodes 20A to 20C are electrodes provided on regions 18A, 18B, and 18C, respectively. The p-side contact electrodes 20A to 20C are made of a transparent electrode such as ITO or IZO. They may be stacked in order from the p-type layer 18 side, with a transparent electrode and a reflective electrode, or with a transparent electrode and a DBR.

[0051] The n-side contact electrode 22 is an electrode provided on the n-type layer 11 exposed at the bottom surface of the third groove 32. When the substrate 10 is made of a conductive material, the n-side contact electrode 22 may be provided on the back surface of the substrate 10 without providing the third groove 32. The material of the n-side contact electrode 22 is, for example, Ti / Al or V / Al.

[0052] The insulating film 24 is provided so as to cover the p-side contact electrodes 20A-20C, the p-type layer 18, the n-side contact electrode 22, and the side and bottom surfaces of the third groove 32. The insulating film 24 is made of, for example, SiO2. Holes 40A-40D penetrating the insulating film 24 are provided at predetermined positions of the insulating film 24. The holes 40A-40D are circular in shape. Alternatively, they may be polygonal, such as square or rectangular. The number of holes 40A-40C is the same as the number of p-side contact electrodes 20A-20C, and the holes 40A-40C are arranged in a direction perpendicular to the strip direction.

[0053] The p-side electrodes 21A to 21C are electrodes provided on the insulating film 24. The p-side electrodes 21A to 21C are connected to the p-side contact electrodes 20A to 20C, respectively, via holes 40A to 40C formed in the insulating film 24. The p-side electrodes 21A to 21C are made of a material such as Ti / Au. Alternatively, a metal with high reflectivity may be provided at the interface between the p-side electrodes 21A to 21C and the p-side contact electrodes 20A to 20C. For example, Ag, Al, Rh, or Ru may be used.

[0054] The n-side electrode 23 is an electrode provided on the insulating film 24. It is connected to the n-side contact electrode 22 via a hole 40D formed in the insulating film 24. The material of the n-side electrode 23 is, for example, Ti / Au. In the first embodiment, a plurality of holes 40D are provided and the holes 40D are arranged in the stripe direction, but there may be only one hole 40D.

[0055] In the light-emitting device of Embodiment 1, applying a forward voltage between the p-side electrode 21A and the n-side electrode 23 causes the third active layer 16 below the p-side contact electrode 20A to emit light, applying a forward voltage between the p-side electrode 21B and the n-side electrode 23 causes the second active layer 14 below the p-side contact electrode 20B to emit light, and applying a forward voltage between the p-side electrode 21C and the n-side electrode 23 causes the first active layer 12 below the p-side contact electrode 20C to emit light. The planar patterns of the light emissions from the first active layer 12, second active layer 14, and third active layer 16 are substantially the same as the planar patterns of the p-side contact electrodes 20A to 20C. These light-emitting regions correspond to the first to third light-emitting regions of the present invention.

[0056] 3. Planar pattern of light-emitting element The planar pattern of the light-emitting element in embodiment 1 will be described with reference to Fig. 2. Note that first groove 30, second groove 31, and third groove 32 are not shown in Fig. 2(a). Fig. 2(b) shows only the planar patterns of p-side contact electrodes 20A to 20C, where the planar pattern of p-side contact electrode 20A substantially matches the planar pattern of the red light-emitting region, the planar pattern of p-side contact electrode 20B substantially matches the planar pattern of the green light-emitting region, and the planar pattern of p-side contact electrode 20C substantially matches the planar pattern of the blue light-emitting region.

[0057] 2, the light-emitting element in embodiment 1 is square. The length of one side of the square is, for example, 50 μm to 1 mm. The third groove 32 is provided in a square ring shape along the outer periphery of the element, and the n-side contact electrode 22 is also square ring shape.

[0058] The patterns of the third groove 32 and the n-side contact electrode 22 are not limited to being circular, and may be linear, L-shaped, or other patterns. However, when the device area is large, a circular pattern like that of embodiment 1 is preferable. This allows current to be sufficiently diffused within the surface, resulting in uniform light emission. For example, when the long side of the rectangular light-emitting device is 200 μm or more, a circular pattern like that of embodiment 1 is preferable.

[0059] The planar patterns of the p-side contact electrodes 20A to 20C are each elongated rectangular (striped). The stripe direction is parallel to one side of the square element. In addition, in a direction perpendicular to the stripe direction, a pattern in which p-side contact electrode 20A, p-side contact electrode 20B, and p-side contact electrode 20C are arranged in this order constitutes one unit, and these units are periodically arranged in a direction perpendicular to the stripe direction.

[0060] Because the planar pattern of the p-side contact electrodes 20A-20C is as described above, color variation depending on the viewing angle of the light emitted from the light-emitting element can be suppressed. That is, in the stripe direction, the light-emitting regions of each color are continuous, so the light emitted by each color is uniform, and in the direction perpendicular to the stripes, the colors are alternately and periodically arranged, so the light emitted by each color is nearly uniform. As a result, color variation is suppressed regardless of the viewing angle.

[0061] The stripe width W1 of the p-side contact electrodes 20A to 20C is uniform, for example, 5 to 50 μm. This range can further suppress color variation due to viewing angle. It is more preferable that it be 5 to 30 μm, and even more preferably 5 to 10 μm. For the same reason, W1 is preferably 0.01 to 0.2 times the length of the short side of the light-emitting element, more preferably 0.01 to 0.1 times, and even more preferably 0.01 to 0.05 times.

[0062] The spacing W2 between the stripes of the p-side contact electrodes 20A to 20C is equal, and W2 is, for example, 1 to 10 μm. Within this range, color variation due to viewing angles can be further reduced.

[0063] When the arrangement of three stripes in the order of p-side contact electrode 20A, p-side contact electrode 20B, and p-side contact electrode 20C is defined as one unit, the number of units is preferably 2 to 20. FIG. 2 shows a case where the number of units is 6. However, in FIG. 1, this is abbreviated to two units. By setting the number of units within this range, color variation due to viewing angle can be further suppressed. A more preferred range is 5 to 20, and even more preferred is 10 to 20.

[0064] The stripe length of the p-side contact electrodes 20A to 20C is preferably 0.5 to 0.95 times the length of one side of the square element. By ensuring a sufficient stripe length, the uniformity of light emission in the stripe direction can be improved and color variation due to viewing angle can be further suppressed. The stripe length is more preferably 0.8 to 0.95 times, and even more preferably 0.9 to 0.95 times.

[0065] 2, the planar patterns of the p-side electrodes 21A to 21C and the n-side electrode 23 are rectangular, and are arranged so that the long sides are perpendicular to the stripe direction of the p-side contact electrodes 20A to 20C. The n-side electrode 23, p-side electrode 21A, p-side electrode 21B, and p-side electrode 21C are arranged in this order at equal intervals. Because the p-side contact electrodes 20A to 20C are striped, the p-side contact electrodes 20A, p-side contact electrodes 20B, and p-side contact electrodes 20C can be connected to each other by a simple rectangular pattern perpendicular to the stripes.

[0066] As described above, in the light-emitting element of Embodiment 1, the planar pattern of p-side contact electrodes 20A-20C is striped, and the p-side contact electrodes 20A, 20B, and 20C are arranged periodically, with the p-side contact electrodes 20A, 20B, and 20C arranged in that order as one unit. Furthermore, the p-side contact electrodes 20A, 20B, and 20C are electrically connected in parallel by p-side electrodes 21A-21C. This reduces color variation depending on the angle at which the light-emitting element is viewed.

[0067] 4. Light-emitting device manufacturing process Next, the manufacturing process of the light emitting device in embodiment 1 will be described with reference to the drawings.

[0068] First, the substrate 10 is prepared, and hydrogen, nitrogen, and, if necessary, ammonia are added to perform a heat treatment on the substrate.

[0069] Next, a buffer layer is formed on the substrate 10, and then an n-type layer 11, a first active layer 12, a first intermediate layer 13, a second active layer 14, a second intermediate layer 15, a third active layer 16, an electron blocking layer 17, and a p-type layer 18 are formed in this order on the buffer layer (see FIG. 3). Each layer is formed using the MOCVD method.

[0070] Next, a portion of the surface of the p-type layer 18 is dry-etched until it reaches the undoped intermediate layer 15A of the second intermediate layer 15, thereby forming a first groove 30, and then dry-etched until it reaches the undoped intermediate layer 13A of the first intermediate layer 13, thereby forming a second groove 31 (see FIG. 4). The planar pattern of the first groove 30 and the second groove 31 is striped.

[0071] Next, a p-type layer 18 is formed continuously on the electron blocking layer 17, on the undoped intermediate layer 15A of the second intermediate layer 15 exposed by the first groove 30, and on the undoped intermediate layer 13A of the first intermediate layer 13 exposed by the second groove 31 (see Figure 5).

[0072] Next, a partial region of the surface of the p-type layer 18 is dry-etched until it reaches the n-type layer 11, thereby forming a third groove 32 (see FIG. 6). The planar pattern of the third groove 32 is a ring-shaped pattern that follows the outer periphery of the device. Then, an n-side contact electrode 22 is formed on the n-type layer 11 exposed at the bottom of the third groove 32, and p-side contact electrodes 20A to 20C are formed at predetermined positions (on regions 18A to 18C) on the p-type layer 18, respectively (see FIG. 7). The n-side contact electrode 22 may be formed before or after the p-side contact electrodes 20A to 20C.

[0073] Next, the insulating film 24 is formed so as to cover the entire upper surface. That is, the insulating film 24 is formed so as to cover the p-side contact electrodes 20A-20C, the p-type layer 18, the n-side contact electrode 22, and the side and bottom surfaces of the third groove 32. Then, holes 40A-40D are formed at predetermined positions in the insulating film 24 (see FIG. 8). The holes 40A-40C have a depth that reaches the p-side contact electrodes 20A-20C, respectively, and the hole 40D has a depth that reaches the n-side contact electrode 22.

[0074] Next, p-side electrodes 21A to 21C and n-side electrode 23 are formed at predetermined positions on insulating film 24, and p-side contact electrodes 20A to 20C are connected to p-side electrodes 23A to 23C via holes 40A to 40C, respectively, and n-side contact electrode 22 is connected to n-side electrode 23 via hole 40D. In this manner, the light-emitting device of embodiment 1 shown in FIGS.

[0075] (Modification 1 of Embodiment 1) Currently, in light-emitting devices using group III nitride semiconductors, the luminous efficiency of red light is lower than that of green and blue light. Therefore, the area of ​​p-side contact electrode 20A may be made larger than the areas of p-side contact electrode 20B and p-side contact electrode 20C. Increasing the area for red light emission more than the areas for green and blue light emission makes it easier to adjust the color balance.

[0076] For example, in the first embodiment, the p-side contact electrodes 20A to 20C have the same width, but as shown in Fig. 9, a pattern may be used in which the width of p-side contact electrode 120A is wider than p-side contact electrodes 120B and 120C. Fig. 9(b) shows only p-side contact electrodes 120A to 120C. The width of p-side contact electrode 120A is preferably 2 to 10 times the width of p-side contact electrode 120B.

[0077] Furthermore, the luminous efficiency of green is higher than that of red, but lower than that of blue. Therefore, the width of p-side contact electrode 120B may be narrower than that of p-side contact electrode 120A and wider than that of p-side contact electrode 120C.

[0078] (Modification 2 of Embodiment 1) In embodiment 1, the p-side contact electrodes 20A to 20C are arranged in a stripe pattern, but in the present invention, a pattern including one or more p-side contact electrodes 20A, one or more p-side contact electrodes 20B, and one or more p-side contact electrodes 20C in a predetermined direction is acceptable as long as the pattern includes multiple units arranged in the predetermined direction.

[0079] The number of p-side contact electrodes 20A to 20C per unit is preferably two or less. This is because if the number of p-side contact electrodes 20A to 20C per unit is too large, there is a risk of significant variation in color depending on the angle. The number of units may be two or more, and is preferably 3 to 20. The arrangement of the units does not necessarily have to be periodic, but is preferably periodic from the perspective of suppressing color variation. The predetermined direction may be any direction passing through the element in a planar view. However, from the perspective of ease of element fabrication and suppression of color variation, it is preferably a direction parallel to one side of the rectangular element.

[0080] For example, the first to third regions may be arranged in a stripe pattern, with the first regions, second regions, or third regions connected at their ends in the stripe direction. In this case, the p-side contact electrodes 20A to 20C may have a comb-like or zigzag pattern. The portions of the comb-like pattern other than the comb teeth and the zigzag pattern other than the bent portions correspond to the first to third regions of the present invention.

[0081] As an example, a planar pattern is shown in FIG. 10. In FIG. 10, p-side contact electrodes 220B and 220C are formed in a comb-like shape with the teeth interlocking, and p-side contact electrode 220A is formed in a zigzag pattern between the teeth of p-side contact electrode 220B and the teeth of p-side contact electrode 220C. FIG. 10(b) shows only the pattern of p-side contact electrodes 220A to 220C. Even with such a pattern, it is possible to suppress variation in the color of the light-emitting element depending on the viewing angle. Furthermore, it is easy to make the area of ​​p-side contact electrode 220A larger than that of p-side contact electrodes 220B and 220C, which makes it easy to balance the light intensity.

[0082] (Other variations) The light-emitting element in embodiment 1 is square in plan view, but may be rectangular. The present invention is particularly effective when the length of the short side of the element in plan view is 200 μm or more. As the element size increases, the color variation due to angle increases, but this can be effectively suppressed according to the present invention. Preferably, the length of the short side is 200 to 1000 μm, and the length of the long side is 400 to 1000 μm.

[0083] Although the light-emitting element in embodiment 1 emits light of three colors with different emission wavelengths, the present invention can be applied to light of two or more colors with different emission wavelengths. Furthermore, the structure of the light-emitting element is not limited to the structure shown in embodiment 1, and any structure having light-emitting regions of two or more colors may be used.

[0084] Although the light emitting element in the first embodiment is of the flip chip type, the present invention can also be applied to face-up type and vertical type elements.

[0085] The light emitting device according to the embodiment can be used in display devices, wavelength division multiplexing communications, and the like. [Explanation of symbols]

[0086] 10: Circuit board 11:N-type layer 12: 1st active layer 13: First middle class 14:Second active layer 15: Second middle class 16: 3rd active layer 17: Electron blocking layer 18:p-type layer 18A~18C: Area 20A-20C: p-side contact electrode 21A~21C:p side electrode 22: n-side contact electrode 23:n side electrode 24: insulating film 30: 1st groove 31:Second groove 32: Third groove

Claims

1. In a light-emitting device using a Group III nitride semiconductor, The light emitting device has a first light emitting region and a second light emitting region that emit light at different wavelengths, the first light-emitting region has a plurality of first regions, the second light-emitting region has a plurality of second regions, the plane patterns of the first light-emitting region and the second light-emitting region are patterns in which a plurality of units, each unit including one or more of the first region and one or more of the second region, are arranged in a predetermined direction; The light-emitting element, wherein the plurality of first regions are electrically connected in parallel, and the plurality of second regions are electrically connected in parallel.

2. The light-emitting device according to claim 1 , wherein the planar patterns of the first region and the second region are stripes extending in a direction perpendicular to the predetermined direction, and the units are periodically arranged in the predetermined direction.

3. The light-emitting element according to claim 1 , wherein the one unit includes one of the first region and one of the second region.

4. The light-emitting element is rectangular in plan view, 3. The light-emitting element according to claim 1, wherein the predetermined direction is a direction parallel to one side of the rectangular light-emitting element.

5. The light-emitting device further includes a third light-emitting region having an emission wavelength different from that of the first light-emitting region and the second light-emitting region, the third light-emitting region has a plurality of third regions, the plane patterns of the first light-emitting region, the second light-emitting region, and the third light-emitting region are patterns in which a plurality of units are arranged in the predetermined direction, each unit being a pattern including one or more of the first region, the second region, and the third region; The light-emitting element according to claim 1 , wherein the third regions are electrically connected in parallel.

6. 6. The light-emitting element according to claim 5, wherein the planar patterns of the first region, the second region, and the third region are stripes extending in a direction perpendicular to the predetermined direction, and the units are periodically arranged in the predetermined direction.

7. The light-emitting element according to claim 5 , wherein the one unit includes one of the first region, one of the second region, and one of the third region.

8. The light-emitting element is rectangular in plan view, 7. The light-emitting element according to claim 5, wherein the predetermined direction is a direction parallel to one side of the rectangular light-emitting element.

9. the first light-emitting region emits red light, the second light-emitting region emits green light, and the third light-emitting region emits blue light; 7. The light-emitting element according to claim 5, wherein an area of ​​the first light-emitting region is larger than an area of ​​the second light-emitting region and an area of ​​the third light-emitting region.

10. the first light-emitting region emits red light, the second light-emitting region emits green light, and the third light-emitting region emits blue light; 7. The light-emitting device according to claim 6, wherein the width of the stripes in the first region is 2 to 10 times the width of the stripes in the second region.

11. A substrate; an n-type layer provided on the substrate and including an n-type Group III nitride semiconductor; a first active layer having a predetermined bandgap energy and disposed on the n-type layer; a first intermediate layer provided on the first active layer and including a Group III nitride semiconductor; a second active layer provided on the first intermediate layer and having a band gap energy different from that of the first active layer; a first groove having a depth reaching the first intermediate layer from the second active layer side; a p-type layer provided on the second active layer and on a bottom surface of the first groove, the p-type layer including a p-type Group III nitride semiconductor; a first p-side contact electrode provided on the p-type layer; a second p-side contact electrode provided on a bottom surface of the first trench, a region of the second active layer under the first p-side contact electrode is the first light-emitting region, The light-emitting device according to claim 1 , wherein a region of the first active layer under the second p-side contact electrode is the second light-emitting region.

12. A substrate; an n-type layer provided on the substrate and including an n-type Group III nitride semiconductor; a first active layer having a predetermined bandgap energy and disposed on the n-type layer; a first intermediate layer provided on the first active layer and including a Group III nitride semiconductor; a second active layer provided on the first intermediate layer and having a band gap energy different from that of the first active layer; a second intermediate layer provided on the second active layer and including a Group III nitride semiconductor; a third active layer provided on the second intermediate layer and having a band gap energy different from that of the first active layer and the second active layer; a first groove having a depth reaching the second intermediate layer from the third active layer side; a second groove having a depth reaching the first intermediate layer from the third active layer side; a p-type layer provided on the third active layer, on a bottom surface of the first groove, and on a bottom surface of the second groove, the p-type layer including a p-type Group III nitride semiconductor; a first p-side contact electrode provided on the p-type layer; a second p-side contact electrode provided on a bottom surface of the first trench; a third p-side contact electrode provided on a bottom surface of the second trench, a region of the third active layer under the first p-side contact electrode is the first light emitting region, a region of the second active layer under the second p-side contact electrode is the second light-emitting region, The light-emitting device according to claim 5 , wherein a region of the first active layer below the third p-side contact electrode is the third light-emitting region.

13. a third groove having a depth reaching the n-type layer from the third active layer side; an n-side contact electrode provided on a bottom surface of the third trench, The light-emitting element according to claim 12 , wherein the third groove and the n-side contact electrode have a planar pattern in the shape of a rectangular ring along the outer periphery of the element.

Images