Nitride semiconductor light-emitting element

Abstract

Provided is a nitride semiconductor light-emitting element that can be driven at a low current and that can reduce a forward voltage. Comprising a first n-type semiconductor layer; a first p-type semiconductor layer disposed on the first n-type semiconductor layer and in contact with the first n-type semiconductor layer; a first superlattice layer disposed on the first p-type semiconductor layer and including a p-type impurity; an active layer disposed on the first superlattice layer; a second n-type semiconductor layer disposed on the active layer; a first electrode electrically connected to the first n-type semiconductor layer; and a second electrode electrically connected to the second n-type semiconductor layer.

Description

Technical Field

[0001] The present disclosure relates to a nitride semiconductor light emitting element. Background Art

[0002] As the use of nitride semiconductor light-emitting elements expands, there is a demand for improved light-emitting efficiency. The light-emitting element disclosed in Patent Document 1 can be driven at a low current.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application No. 2020-501345 Summary of the invention

[0006] Technical problem to be solved by the invention

[0007] However, as the use of nitride semiconductor light-emitting devices expands, they are required to be driven with a lower current and have a further reduction in forward voltage.

[0008] Therefore, an object of the present disclosure is to provide a nitride semiconductor light emitting element that can be driven with a low current and can reduce a forward voltage.

[0009] Technical solutions for solving technical problems

[0010] In order to achieve the above objectives, the nitride semiconductor light emitting device of the present invention comprises:

[0011] a first n-type semiconductor layer;

[0012] a first p-type semiconductor layer, which is disposed on the first n-type semiconductor layer and is in contact with the first n-type semiconductor layer;

[0013] A first superlattice layer, which is disposed on the first p-type semiconductor layer and contains p-type impurities;

[0014] an active layer disposed on the first superlattice layer;

[0015] A second n-type semiconductor layer, disposed on the active layer;

[0016] a first electrode electrically connected to the first n-type semiconductor layer;

[0017] A second electrode is electrically connected to the second n-type semiconductor layer.

[0018] Effects of the Invention

[0019] According to the nitride semiconductor light emitting element of the present disclosure configured as described above, it is possible to provide a nitride semiconductor light emitting element that can be driven at a low current and has a low forward voltage. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a cross-sectional view of the nitride semiconductor light-emitting element according to Embodiment 1.

[0021] Figure 2 It is a magnified representation Figure 1 FIG. 4 is a cross-sectional view of the first superlattice layer 40 .

[0022] Figure 3 This is a cross-sectional view of a nitride semiconductor light-emitting element according to Embodiment 2.

[0023] Figure 4 This is a cross-sectional view of a nitride semiconductor light-emitting element according to Embodiment 3.

[0024] Figure 5 It is a magnified representation Figure 4 A cross-sectional view of the second superlattice layer 90 .

[0025] Figure 6 It is a cross-sectional view of the nitride semiconductor light-emitting element of Embodiment 4-1.

[0026] Figure 7 It is a cross-sectional view of the nitride semiconductor light-emitting element of Embodiment 4-2. DETAILED DESCRIPTION

[0027] Hereinafter, the embodiments and examples for implementing the present disclosure will be described with reference to the accompanying drawings. It should be noted that the nitride semiconductor light emitting element and the method for manufacturing the nitride semiconductor light emitting element described below are methods for concretizing the technical ideas of the present disclosure, and unless otherwise specified, the present invention is not limited to the following methods.

[0028] In the various drawings, the same reference numerals are sometimes used to indicate components with the same functions. In consideration of the ease of explanation or understanding of the main points, the components are sometimes divided into implementation modes and examples for convenience, but partial replacement or combination of the structures shown in different implementation modes and examples is possible. In the implementation modes and examples described later, the description of matters common to the above is omitted, and only the differences are described. In particular, the same effects based on the same structure are sometimes not mentioned in order according to the implementation modes and examples. The sizes and positional relationships of the components shown in the various drawings are sometimes exaggerated for the purpose of clarifying the description.

[0029] like Figure 1As shown in the figures, the nitride semiconductor light-emitting element of the embodiment of the present disclosure includes: a first n-type semiconductor layer 20; a first p-type semiconductor layer 30, which is arranged on the first n-type semiconductor layer 20 and connected to the first n-type semiconductor layer 20; a first superlattice layer 40, which is arranged on the first p-type semiconductor layer 30 and contains p-type impurities; a first active layer 50, which is arranged on the first superlattice layer 40; a second n-type semiconductor layer 60, which is arranged on the first active layer 50; a first electrode 11, which is electrically connected to the first n-type semiconductor layer 20; and a second electrode 12, which is electrically connected to the second n-type semiconductor layer 60.

[0030] The nitride semiconductor light emitting element of the embodiment of the present disclosure configured as described above can reduce the forward voltage Vf and improve the light emission intensity with respect to the applied voltage by providing the first superlattice layer 40 containing p-type impurities between the first p-type semiconductor layer 30 and the first active layer 50 .

[0031] Here, the nitride semiconductor in this specification refers to a binary to quaternary compound semiconductor containing at least one of aluminum (Al), gallium (Ga), and indium (In) and nitrogen (N), and can be contained in a nitride semiconductor composed of In. x Al y Ga 1-x-y In the chemical formula consisting of N (0≤x≤1, 0≤y≤1, x+y≤1), semiconductors of all compositions in which the composition ratios x and y are changed within their respective ranges.

[0032] Hereinafter, the nitride semiconductor light emitting element according to the embodiment of the present disclosure will be described in detail.

[0033] [Implementation method 1]

[0034] Figure 1 is a cross-sectional view of a nitride semiconductor light emitting element according to Embodiment 1. Figure 2 yes Figure 1 A cross-sectional view of the first superlattice layer 40 in the nitride semiconductor light emitting element.

[0035] like Figure 1 As shown, the semiconductor light emitting element of Embodiment 1 includes, for example, a substrate 10 and a first light emitting portion 1 disposed on the substrate 10. The first light emitting portion 1 includes: a first n-type semiconductor layer 20, which is disposed on the substrate 10; a first p-type semiconductor layer 30, which is disposed on the first n-type semiconductor layer 20; a first superlattice layer 40, which is disposed on the first p-type semiconductor layer 30 and includes p-type impurities; a first active layer 50, which is disposed on the first superlattice layer 40; and a second n-type semiconductor layer 60, which is disposed on the first active layer 50, each of which is composed of a nitride semiconductor.

[0036] Furthermore, the nitride semiconductor light-emitting element of embodiment 1 includes: a first electrode 11, which is electrically connected to the first n-type semiconductor layer 20 by, for example, ohmic contact with the first n-type semiconductor layer 20; and a second electrode 12, which is electrically connected to the second n-type semiconductor layer 60 by, for example, ohmic contact with the second n-type semiconductor layer 60.

[0037] In the nitride semiconductor light emitting element of Embodiment 1 constructed as described above, the first n-type semiconductor layer 20 is in contact with the first p-type semiconductor layer 30, and the current injected from the first electrode 11 is injected into the first active layer 50 via the first n-type semiconductor layer 20 and the first p-type semiconductor layer 30, so that the first light emitting portion 1 emits light. That is, in the nitride semiconductor light emitting element of Embodiment 1, the first electrode 11 arranged in the first n-type semiconductor layer 20 is a positive electrode, and the second electrode 12 is a negative electrode.

[0038] Furthermore, the nitride semiconductor light emitting element of the first embodiment of the present disclosure reduces the forward voltage Vf and improves the light emission intensity relative to the applied voltage by configuring the first superlattice layer 40 containing p-type impurities between the first p-type semiconductor layer 30 containing p-type impurities and the first active layer 50.

[0039] That is, the invention of the nitride semiconductor light-emitting element of embodiment 1 of the present disclosure is completed based on the insights obtained independently by the inventors, that is, in a light-emitting element in which a current injected from a positive electrode electrically connected to a first n-type semiconductor layer 20 is injected into a first active layer 50 via the first n-type semiconductor layer 20 and the first p-type semiconductor layer 30, by configuring a first superlattice layer 40 containing p-type impurities between the first p-type semiconductor layer 30 containing p-type impurities and having p-type conductivity and the first active layer 50, the supply efficiency of holes to the first active layer 50 can be improved, the forward voltage Vf can be reduced, and the luminous intensity relative to the applied voltage can be improved.

[0040] Hereinafter, specific examples and more preferred embodiments of the first superlattice layer 40 will be described based on the findings obtained by the present inventors.

[0041] <First superlattice layer>

[0042] Figure 2 This is an enlarged cross-sectional view showing the first superlattice layer 40 in the nitride semiconductor light emitting element according to the first embodiment.

[0043] like Figure 2As shown, the first superlattice layer 40 includes a first layer 41 and a second layer 42. The first layer 41 and the second layer 42 are alternately stacked. The lattice constant of the second layer 42 is different from the lattice constant of the first layer 41. By configuring the first superlattice layer 40 between the first p-type semiconductor layer 30 and the first active layer 50, the strain of the crystal of the first active layer 50 caused by the difference in the lattice constant between the first p-type semiconductor layer 30 and the first active layer 50 can be reduced. By reducing the strain of the crystal of the first active layer 50, the internal quantum efficiency of the first active layer 50 can be improved. As a result, the luminous efficiency can be improved.

[0044] The composition of the first layer 41 and the second layer 42 is preferably set in consideration of the composition or band gap of the first active layer 50, or in consideration of the composition or band gap of the well layer when the first active layer 50 has a quantum well structure. For example, when the well layer is composed of an InGaN layer, the first layer 41 and the second layer 42 are preferably set to have a composition ratio of In smaller than that of the well layer.

[0045] The first layer 41 and the second layer 42 have different In composition ratios, for example, so that the lattice constant of the first layer 41 is different from the lattice constant of the second layer 42. At least one of the first layer 41 and the second layer 42 is a layer doped with p-type impurities. By doping at least one of the first layer 41 and the second layer 42 with p-type impurities, the forward voltage Vf can be reduced as described above. The p-type impurity concentration of at least one of the first layer 41 and the second layer 42 is preferably 1×10 18 cm -3 Above and 3×10 19 cm -3 In addition, the concentration of the p-type impurity doped in at least one of the first layer 41 and the second layer 42 is preferably lower than the p-type impurity concentration of the first p-type semiconductor layer 30 .

[0046] For example, the In composition ratio of the first layer 41 can be made greater than the In composition ratio of the second layer 42. In this case, the forward voltage Vf can be easily reduced by making the p-type impurity concentration of the first layer 41 greater than the p-type impurity concentration of the second layer 42. This is considered to be because In is easily distributed near the upper surface of the first layer 41, and thus the surface roughness of the upper surface of the first layer 41 is easily reduced, and even if the first layer 41 is doped with p-type impurities, the crystallinity of the first superlattice layer 40 is not easily deteriorated.

[0047] When the In composition ratio of the first layer 41 is greater than that of the second layer 42 and the p-type impurity concentration of the first layer 41 is greater than that of the second layer 42, the p-type impurity concentration of the first layer 41 is preferably 1×10 18 cm -3 Above and 3×10 19 cm -3By setting the p-type impurity concentration of the first layer 41 to such a range, the efficiency of supplying holes to the first active layer 50 can be improved, and the degradation of the crystallinity of the first superlattice layer 40 can be reduced. In this case, the second layer 42 is preferably a non-doped layer.

[0048] In addition, when the In composition ratio of the first layer 41 is greater than the In composition ratio of the second layer 42 and the p-type impurity concentration of the first layer 41 is greater than the p-type impurity concentration of the second layer 42, the thickness of the first layer 41 is preferably thinner than the thickness of the second layer 42. By reducing the thickness of the first layer 41 having a larger p-type impurity concentration, the deterioration of the crystallinity of the first superlattice layer 40 can be reduced.

[0049] In particular, when the first n-type semiconductor layer 20 and the first p-type semiconductor layer 30 are tunnel-joined, as described later, the impurity concentration in the junction between the first n-type semiconductor layer 20 and the first p-type semiconductor layer 30 becomes high, but by configuring the first superlattice layer 40, the diffusion of impurities into the first active layer 50 can be reduced, and the reduction in luminous efficiency caused by the diffusion of impurities into the first active layer 50 can be effectively reduced.

[0050] The nitride semiconductor light-emitting element of embodiment 1 having a first superlattice layer 40 constructed as described above can reduce the forward voltage Vf and increase the luminous intensity relative to the applied voltage by configuring the first superlattice layer 40 containing p-type impurities between the first p-type semiconductor layer 30 containing p-type impurities and having p-type conductivity and the first active layer 50.

[0051] Hereinafter, each structure of the nitride semiconductor light emitting element according to Embodiment 1 will be described in detail.

[0052] <Substrate>

[0053] The material of the substrate 10 is, for example, sapphire, Si, SiC, GaN, etc. The substrate 10 can be a growth substrate for growing a nitride semiconductor layer. A buffer layer may also be arranged between the substrate 10 and the first n-type semiconductor layer 20. The substrate 10 may be removed after the semiconductor layer such as the first n-type semiconductor layer 20 is grown.

[0054] <First n-type semiconductor layer 20 >

[0055] The first n-type semiconductor layer 20 can be composed of a nitride semiconductor layer containing n-type impurities such as silicon (Si) and germanium (Ge). For example, when the first active layer 50 is composed of a nitride semiconductor layer containing In, the nitride semiconductor constituting the first n-type semiconductor layer 20 is, for example, an n-type GaN layer, which may contain In and Al. In addition, when the first active layer 50 is composed of a nitride semiconductor containing Al, for example, the nitride semiconductor constituting the first n-type semiconductor layer 20 is, for example, an n-type AlGaN layer, which may further contain In.

[0056] In addition, the first n-type semiconductor layer 20 may include one or more n-type nitride semiconductor layers. For example, it is preferable to include 8×10 19 cm -3 Above and 8×10 20 cm -3 The following nitride semiconductor layer doped with Si as an n-type impurity at a relatively high concentration forms a tunnel junction with the first p-type semiconductor layer 30. The layer forming a tunnel junction with the first p-type semiconductor layer 30 is composed of 8×10 19 cm -3 Above and 8×10 20 cm -3 The first n-type semiconductor layer 20 preferably includes a nitride semiconductor layer containing n-type impurities in addition to the above-mentioned tunnel junction layer, and the n-type impurity concentration of the nitride semiconductor layer containing n-type impurities other than the layer for tunnel junction is preferably set to, for example, 1×10 18 cm -3 Above and 1×10 19 cm -3 The following, for example, can be obtained by 18 cm -3 Above and 1×10 19 cm -3 The first n-type semiconductor layer 20 is composed of an n-type GaN layer containing Si as an n-type impurity. In addition, the first n-type semiconductor layer 20 may include a non-doped semiconductor layer in part. Here, the non-doped semiconductor layer refers to a layer to which n-type impurities and p-type impurities are not intentionally added. The overall thickness of the first n-type semiconductor layer 20 is, for example, not less than 5 μm and not more than 15 μm.

[0057] <First p-type semiconductor layer 30 >

[0058] The first p-type semiconductor layer 30 may be composed of a nitride semiconductor layer containing p-type impurities such as magnesium (Mg) and zinc (Zn). For example, when the first active layer 50 is composed of a nitride semiconductor layer containing In, the nitride semiconductor constituting the first p-type semiconductor layer 30 is, for example, a p-type GaN layer, which may contain In and Al. In addition, when the first active layer 50 is composed of a nitride semiconductor containing Al, for example, the nitride semiconductor constituting the first p-type semiconductor layer 30 is, for example, a p-type AlGaN layer, which may further contain In.

[0059] In addition, the first p-type semiconductor layer 30 may include one or more p-type nitride semiconductor layers, for example, preferably including 8×10 19 cm -3 Above and 8×10 20 cm -3 The nitride semiconductor layer doped with Mg as a p-type impurity at a relatively high concentration is used as a layer for tunnel junction with the layer included in the uppermost layer of the first n-type semiconductor layer 20. The layer for tunnel junction in the first p-type semiconductor layer is composed of 8×10 19 cm -3 Above and 8×10 20 cm -3 The first p-type semiconductor layer 30 preferably includes a nitride semiconductor layer containing p-type impurities in addition to the above-mentioned layer for tunneling. The p-type impurity concentration of the nitride semiconductor layer containing p-type impurities other than the layer for tunneling is preferably 1×10 18 cm -3 Above and 1×10 19 cm -3 Below, for example, it can be obtained by taking 1×10 18 cm -3 Above and 1×10 19 cm -3 The first p-type semiconductor layer 30 may include a p-type GaN layer containing Mg as a p-type impurity. The first p-type semiconductor layer 30 may include a non-doped semiconductor layer in part. The thickness of the first p-type semiconductor layer 30 as a whole may be set to, for example, 0.04 μm or more and 0.2 μm or less.

[0060] <First active layer 50>

[0061] The first active layer 50 is, for example, a nitride semiconductor layer that emits light with a peak wavelength in the range of 200 nm to 760 nm. The first active layer 50 may be, for example, a multi-quantum well structure having a plurality of well layers and a plurality of barrier layers, or a single quantum well structure including a well layer and barrier layers on both sides thereof. When the first active layer 50 is a single or multi-quantum well, the well layer may be, for example, GaN, InGaN or AlGaN, and the barrier layer may be, for example, AlGaN or GaN.

[0062] <Second n-type semiconductor layer 60 >

[0063] The second n-type semiconductor layer 60 includes, for example, a nitride semiconductor layer containing n-type impurities such as silicon (Si). The second n-type semiconductor layer 60 may include one or more n-type nitride semiconductor layers, or may include an undoped semiconductor layer in part. For example, in the case where the first active layer 50 is composed of a nitride semiconductor layer containing In, the nitride semiconductor constituting the second n-type semiconductor layer 60 is, for example, an n-type GaN layer, and may also contain In and Al. In addition, in the case where the first active layer 50 is composed of a nitride semiconductor containing Al, the nitride semiconductor constituting the second n-type semiconductor layer 60 is, for example, an n-type AlGaN layer, and may also contain In.

[0064] The thickness of the second n-type semiconductor layer 60 can be, for example, 0.1 μm to 15 μm, preferably 0.1 μm to 5 μm, more preferably 0.1 μm to 3 μm, and particularly preferably 0.1 μm to 1 μm. The impurity concentration of the second n-type semiconductor layer 60 can be, for example, 1×10 18 cm -3 Above and 1×10 19 cm -3 the following.

[0065] <First and second electrodes>

[0066] The first electrode 11 and the second electrode 12 are electrodes electrically connected to the first n-type semiconductor layer 20 and the second n-type semiconductor layer 60, i.e., n-type semiconductor layers, and can be composed of, for example, metals such as Au, Pt, Pd, Rh, Ni, W, Mo, Cr, Ti, Al, Cu, or alloys containing these metals. The first electrode 11 and the second electrode 12 can be either a single-layer structure or a laminated structure in which a plurality of layers are laminated. For example, the first electrode 11 and the second electrode 12 can be a laminated structure in which a Ti layer, an Al-Si-Cu alloy layer, a Ti layer, a Pt layer, an Au layer, and a Ti layer are laminated in sequence.

[0067] [Implementation method 2]

[0068] Figure 3 This is a cross-sectional view of a nitride semiconductor light-emitting element according to Embodiment 2.

[0069] like Figure 3 As shown, the nitride semiconductor light emitting element of the second embodiment includes a second light emitting portion 2 on the first light emitting portion 1 of the nitride semiconductor light emitting element of the first embodiment. The second light emitting portion 2 includes a second n-type semiconductor layer 60 shared with the first light emitting portion, a second active layer 70 disposed on the second n-type semiconductor layer 60, and a second p-type semiconductor layer 80 disposed on the second active layer 70. In addition, the nitride semiconductor light emitting element of the second embodiment includes a third electrode 13 electrically connected to the second p-type semiconductor layer 80. Here, the third electrode 13 may include a pad electrode 13a and an electrode layer 13b disposed in contact with the second p-type semiconductor layer 80. It should be noted that, in the nitride semiconductor light emitting element of the second embodiment, the second electrode 12 is, for example, disposed on the second n-type semiconductor layer 60 exposed by removing the second active layer 70 and the second p-type semiconductor layer 80. In addition, the first electrode 11 is disposed on the first n-type semiconductor layer 20 in the same manner as the nitride semiconductor light emitting element of the first embodiment.

[0070] In the nitride semiconductor light emitting element of the second embodiment configured as described above, the first electrode 11 functions as a positive electrode of the first light emitting portion 1. In addition, the third electrode 13 functions as a positive electrode of the second light emitting portion 2. In addition, the second electrode 12 functions as a negative electrode of the first light emitting portion 1 and the second light emitting portion 2.

[0071] In the nitride semiconductor light emitting element of Embodiment 2, the first light emitting portion 1 can be lit by applying a voltage between the first electrode 11 and the second electrode 12. In addition, the second light emitting portion 2 can be lit by applying a voltage between the third electrode 13 and the second electrode 12. In this way, the first light emitting portion 1 and the second light emitting portion 2 can be lit independently.

[0072] In addition, even when the first light-emitting section 1 and the second light-emitting section 2 are lit at the same time, the luminous intensity of the first light-emitting section 1 and the second light-emitting section 2 can be individually controlled by adjusting the voltage applied between the first electrode 11 and the second electrode 12 and the voltage applied between the third electrode 13 and the second electrode 12.

[0073] Furthermore, in the nitride semiconductor light emitting element of embodiment 2, the first light emitting portion 1 has the same structure as the nitride semiconductor light emitting element of embodiment 1, and thus can reduce the forward voltage Vf and improve the light emission intensity relative to the applied voltage.

[0074] In the nitride semiconductor light emitting element of the second embodiment configured as described above, the first light emitting portion 1 and the second light emitting portion 2 may have the same peak emission wavelength or different peak emission wavelengths. In other words, the peak emission wavelength of the first active layer 50 and the peak emission wavelength of the second active layer 70 may be the same or different. In the nitride semiconductor light emitting element of the second embodiment, the second active layer 70 is located above the first active layer 50. Therefore, when the peak emission wavelength of the first active layer 50 is different from the peak emission wavelength of the second active layer 70, the color mixing property can be improved. It should be noted that since the composition of the first active layer 50 is different from that of the second active layer 70, the peak emission wavelength of the first active layer 50 is different from that of the second active layer 70. For example, by making the In composition ratio of the first active layer 50 different from that of the second active layer 70, the peak emission wavelength of the first active layer 50 is different from that of the second active layer 70.

[0075] For example, in a nitride semiconductor light-emitting element, the luminous efficiency differs depending on the peak wavelength of the luminous emission. In the nitride semiconductor light-emitting element of Embodiment 2, as described above, even when the first light-emitting portion 1 and the second light-emitting portion 2 are lit at the same time, by adjusting the voltage applied between the first electrode 11 and the second electrode 12 and the voltage applied between the third electrode 13 and the second electrode 12, the luminous intensity of the first light-emitting portion 1 and the second light-emitting portion 2 can be controlled respectively. Therefore, in the nitride semiconductor light-emitting element of Embodiment 2, even when the luminous peak wavelength of the first active layer 50 is different from the luminous peak wavelength of the second active layer 70, by adjusting the voltage applied between the first electrode 11 and the second electrode 12 and the voltage applied between the third electrode 13 and the second electrode 12, it is possible to make it easy to obtain a light-emitting element of any luminous color.

[0076] Hereinafter, each structure of the nitride semiconductor light emitting device according to Embodiment 2 will be described in detail. It should be noted that the description of the same structure as that of Embodiment 1 will be omitted.

[0077] <Second Active Layer 70>

[0078] The second active layer 70 is, for example, a nitride semiconductor layer that emits light with a peak wavelength in the range of 200 nm to 760 nm. The second active layer 70 can be, for example, a multi-quantum well structure having a plurality of well layers and a plurality of barrier layers, or a single quantum well structure including a well layer and barrier layers on both sides thereof. When the second active layer 70 is a single or multi-quantum well, the well layer is, for example, GaN, InGaN or AlGaN, and the barrier layer is, for example, AlGaN or GaN.

[0079] <Second p-type semiconductor layer 80 >

[0080] The second p-type semiconductor layer 80 can be composed of a nitride semiconductor layer containing p-type impurities such as Mg and Zn. For example, when the second active layer 70 is composed of a nitride semiconductor layer containing In, the nitride semiconductor constituting the second p-type semiconductor layer 80 is, for example, a p-type GaN layer, which may contain In and Al. In addition, when the second active layer 70 is composed of a nitride semiconductor containing Al, for example, the nitride semiconductor constituting the second p-type semiconductor layer 80 is, for example, a p-type AlGaN layer, which may further contain In.

[0081] In addition, the second p-type semiconductor layer 80 may include one or more p-type nitride semiconductor layers. The second p-type semiconductor layer 80 may include a non-doped semiconductor layer in part. The overall thickness of the second p-type semiconductor layer 80 may be set to, for example, 0.04 μm or more and 0.2 μm or less.

[0082] <Third electrode 13>

[0083] The third electrode 13 includes, for example, a pad electrode 13a and an electrode layer 13b disposed in contact with the second p-type semiconductor layer 80. The electrode layer 13b can be made of, for example, ITO, ZnO, IZO, In 2 O 3 The electrode layer 13b may be made of a light-transmitting metal oxide such as Au, Pt, Pd, Rh, Ni, W, Mo, Cr, Ti, Al, Cu, or an alloy containing these metals.

[0084] [Implementation method 3]

[0085] Figure 4 This is a cross-sectional view of a nitride semiconductor light-emitting element according to Embodiment 3.

[0086] like Figure 4 As shown, the nitride semiconductor light emitting element of embodiment 3 is constructed similarly to the nitride semiconductor light emitting element of embodiment 2 except that a second superlattice layer 90 is provided between the second n-type semiconductor layer 60 and the second active layer 70 .

[0087] That is, the second light emitting portion 2 of the nitride semiconductor light emitting element according to the third embodiment includes the second superlattice layer 90 .

[0088] Figure 5 It is a magnified representation Figure 4 A cross-sectional view of the second superlattice layer 90 .

[0089] Hereinafter, the second superlattice layer 90 will be described in detail.

[0090] <Second Superlattice Layer 90>

[0091] In the present embodiment, the second superlattice layer 90 has a third layer 91 and a fourth layer 92 having a lattice constant different from that of the third layer 91. The second superlattice layer 90 is a layer in which the third layer 91 and the fourth layer 92 are alternately stacked. The third layer 91 and the fourth layer 92 have different In composition ratios, for example. By configuring the second superlattice layer 90 between the second n-type semiconductor layer 60 and the second active layer 70, the strain of the crystal of the second active layer 70 caused by the difference between the lattice constant of the second n-type semiconductor layer 60 and the lattice constant of the second active layer 70 can be reduced. By reducing the strain of the crystal of the second active layer 70, the internal quantum efficiency can be improved, and the luminous efficiency can be improved. In addition, as described below, various effects can be obtained by appropriately selecting the impurity concentration, composition, thickness, etc. of the third layer 91 and the fourth layer 92.

[0092] (Implementation method 3-1)

[0093] In Embodiment 3-1, the third layer 91 and the fourth layer 92 are both set as undoped layers. Generally, the more the layers of different compositions of nitride semiconductors are stacked on the growth substrate, the more the crystallinity is deteriorated on the upper layer side. Therefore, in the second superlattice layer 90 stacked on the first light-emitting portion 1, by setting the third layer 91 and the fourth layer 92 as undoped layers, the deterioration of the crystallinity of the second superlattice layer 90 can be reduced.

[0094] (Implementation method 3-2)

[0095] In Embodiment 3-2, at least one of the third layer 91 and the fourth layer 92 is a layer containing an n-type impurity. For example, Si can be cited as an n-type impurity. The n-type impurity concentration of at least one of the third layer 91 and the fourth layer 92 is preferably 1×10 18 cm -3 Above and 1×10 19 cm -3 By doing so, the electron supply efficiency to the second active layer 70 can be improved, and the light emission efficiency can be improved.

[0096] In addition, in Embodiment 3-2, the third layer 91 is preferably a layer containing n-type impurities, and further, the third layer 91 is preferably a layer containing In, such as an InGaN layer. As a result, the efficiency of supplying electrons to the second active layer 70 based on the n-type impurities can be improved, and the deterioration of the crystallinity of the second superlattice layer 90 caused by the n-type impurities can be reduced. The reason why the deterioration of the crystallinity of the second superlattice layer 90 caused by the n-type impurities can be reduced is considered to be because In is easily distributed near the upper surface of the third layer 91, so that the surface roughness of the upper surface of the third layer 91 is easily reduced. As a result, even if the third layer 91 is doped with n-type impurities, the crystallinity of the second superlattice layer 90 is not easily deteriorated.

[0097] In addition, in Embodiment 3-2, it is more preferable to set the third layer 91 as a layer containing n-type impurities and In, and set the fourth layer 92 as a layer having a lower n-type impurity concentration than the third layer 91 and a lower In composition ratio than the third layer 91. As a result, the n-type impurity concentration of the second superlattice layer 90 becomes higher, and the crystallinity of the second superlattice layer 90 is less likely to deteriorate. It should be noted that, in this case, the fourth layer 92 may be a layer not containing In. In addition, the fourth layer 92 may be a non-doped layer.

[0098] Furthermore, in Embodiment 3-2, when the third layer 91 is a layer containing an n-type impurity and In, and the fourth layer 92 is a layer having a lower n-type impurity concentration and a lower In composition ratio than the third layer 91, the thickness of the third layer 91 is preferably thinner than the thickness of the fourth layer 92. By reducing the thickness of the third layer 91 having a higher n-type impurity concentration than the fourth layer 92, the deterioration of the crystallinity of the second superlattice layer 90 can be reduced.

[0099] [Implementation method 4]

[0100] Figure 6 and Figure 7 This is a cross-sectional view of a nitride semiconductor light-emitting element according to a fourth embodiment.

[0101] Here, Figure 6 is a cross-sectional view of a nitride semiconductor light-emitting element according to Embodiment 4-1, Figure 7 is a cross-sectional view of a nitride semiconductor light emitting element according to Embodiment 4-2. Figure 6 and Figure 7 As shown, in the nitride semiconductor light emitting element of Embodiment 4-1 and the nitride semiconductor light emitting element of Embodiment 4-2, the first n-type semiconductor layer 20 and the first p-type semiconductor layer 30 are configured similarly.

[0102] Specifically, in the nitride semiconductor light emitting device of Embodiment 4-1 and the nitride semiconductor light emitting device of Embodiment 4-2,

[0103] (a) The first n-type semiconductor layer 20 includes a third superlattice layer 22 and a first bonding layer 21 disposed on the third superlattice layer 22 and in contact with the first p-type semiconductor layer 30 .

[0104] (b) The first p-type semiconductor layer 30 includes the second bonding layer 31 that is tunnel-bonded to the first bonding layer 21 .

[0105] Moreover, if Figure 6 As shown, the nitride semiconductor light emitting device of Embodiment 4-1 is configured similarly to the nitride semiconductor light emitting device of Embodiment 2 except for the first n-type semiconductor layer 20 and the first p-type semiconductor layer 30. Figure 7 As shown, the nitride semiconductor light emitting device of Embodiment 4-2 is configured similarly to the nitride semiconductor light emitting device of Embodiment 3 except for the first n-type semiconductor layer 20 and the first p-type semiconductor layer 30 .

[0106] Hereinafter, the nitride semiconductor light-emitting element according to Embodiment 4 will be described in detail.

[0107] In the following description, when the common structure of the nitride semiconductor light emitting element of Embodiment 4-1 and the nitride semiconductor light emitting element of Embodiment 4-2 is collectively described, only the nitride semiconductor light emitting element of Embodiment 4 is described.

[0108] As described in Embodiment 1 and the like, it is preferred that the first n-type semiconductor layer 20 includes a layer that is tunnel-bonded with the first p-type semiconductor layer 30, the first p-type semiconductor layer 30 includes a layer that is tunnel-bonded with the first n-type semiconductor layer 20, and the first n-type semiconductor layer 20 is tunnel-bonded with the first p-type semiconductor layer 30. Here, when the first n-type semiconductor layer 20 is tunnel-bonded with the first p-type semiconductor layer 30, it is preferred that the forward voltage Vf is reduced without deteriorating. Therefore, the nitride semiconductor light-emitting element of Embodiment 4 includes layers that are tunnel-bonded with the first n-type semiconductor layer 20 and the first p-type semiconductor layer 30, respectively, and further, a superlattice layer is arranged on the substrate 10 side of the layer that is tunnel-bonded with the second p-type semiconductor layer in the first n-type semiconductor layer 20.

[0109] That is, refer to Figure 6 and Figure 7 As described above, in the nitride semiconductor light-emitting element of embodiment 4, (a) the first n-type semiconductor layer 20 includes a third superlattice layer 22 and a first bonding layer 21 arranged on the third superlattice layer 22 and connected to the first p-type semiconductor layer 30, and (b) the first p-type semiconductor layer 30 includes a second bonding layer 31 that is tunnel-bonded to the first bonding layer 21.

[0110] Specifically, if Figure 6 and Figure 7 As shown, in the nitride semiconductor light emitting element of the fourth embodiment, the first n-type semiconductor layer 20 includes an n-type contact layer 23, a third superlattice layer 22, and a first bonding layer 21 in order from the substrate 10 side. Here, the first bonding layer 21 is the uppermost layer on the first n-type semiconductor layer 20 on the first p-type semiconductor layer 30 side. In addition, in the nitride semiconductor light emitting element of the fourth embodiment, the first p-type semiconductor layer 30 includes a second bonding layer 31 and a third p-type semiconductor layer 32 in order from the substrate 10 side. Here, the second bonding layer 31 is a layer located on the first n-type semiconductor layer 20 side in the first p-type semiconductor layer 30 and tunnel-bonded with the first bonding layer 21.

[0111] In the nitride semiconductor light emitting element of the fourth embodiment configured as above, the first n-type semiconductor layer 20 and the first p-type semiconductor layer 30 are tunnel-joined, and the first n-type semiconductor layer 20 further includes the third superlattice layer 22. Thus, carriers generated in the layers performing the tunnel-joining can effectively contribute to light emission, thereby reducing the forward voltage Vf.

[0112] Specifically, it is considered that the forward voltage Vf can be reduced based on the following reasons.

[0113] Generally, the first bonding layer 21 and the second bonding layer 31 , which are layers that perform tunnel bonding, have impurity concentrations set higher than those of other layers as described later.

[0114] Therefore, by using the first bonding layer 21 and the second bonding layer 31 having a higher impurity concentration than other layers, more carriers can be generated than in other layers, thereby reducing the forward voltage Vf.

[0115] However, by using the first bonding layer 21 and the second bonding layer 31 having a higher impurity concentration than other layers, more generated carriers may not effectively contribute to light emission, but instead the forward voltage Vf may increase.

[0116] The present inventors speculate that the reason why a large amount of generated carriers cannot effectively contribute to light emission may be due to defects existing in the first bonding layer 21 and the second bonding layer 31 .

[0117] Specifically, it is considered that carriers generated by defects existing in the first bonding layer 21 and the second bonding layer 31 are trapped, and thus the carriers cannot effectively contribute to light emission.

[0118] Therefore, in order to reduce defects generated in the first bonding layer 21 and the second bonding layer 31, when the third superlattice layer 22 is arranged in the first n-type semiconductor layer 20, the forward voltage Vf can be reduced, thereby completing the invention of the nitride semiconductor light emitting element of the fourth embodiment.

[0119] Hereinafter, the structures of the first n-type semiconductor layer 20 and the first p-type semiconductor layer 30 in the nitride semiconductor light emitting element according to the fourth embodiment will be described in more detail.

[0120] <First n-type semiconductor layer 20 >

[0121] In the nitride semiconductor light emitting element of the fourth embodiment, as described above, the first n-type semiconductor layer 20 includes the n-type contact layer 23 , the third superlattice layer 22 , and the first bonding layer 21 in this order from the substrate 10 side.

[0122] (n-type contact layer 23)

[0123] The n-type contact layer 23 is a layer in which the first electrode 11 is formed, and can be composed of a nitride semiconductor layer containing n-type impurities such as silicon (Si) and germanium (Ge). For example, when the first active layer 50 is composed of a nitride semiconductor layer containing In, the nitride semiconductor constituting the n-type contact layer 23 is, for example, an n-type GaN layer, which can contain In and Al. In addition, when the first active layer 50 is composed of a nitride semiconductor containing Al, the nitride semiconductor constituting the n-type contact layer 23 is, for example, an n-type AlGaN layer, which can further contain In.

[0124] The n-type impurity concentration of the n-type contact layer 23 is preferably 1×10 18 cm -3 Above and 1×10 19 cm -3 The following, for example, can be obtained by 18 cm -3 Above and 1×10 19 cm -3 The following is a composition of an n-type GaN layer containing Si as an n-type impurity.

[0125] (Third Superlattice Layer 22)

[0126] The third superlattice layer 22 is a layer for reducing defects in the first bonding layer 21 and the second bonding layer 31 that are tunnel-bonded, and is disposed between the n-type contact layer 23 and the first bonding layer 21 .

[0127] The third superlattice layer 22 has a fifth layer and a sixth layer. The fifth layer and the sixth layer are alternately stacked, and the lattice constant of the fifth layer is different from the lattice constant of the sixth layer. By configuring the third superlattice layer 22 between the n-type contact layer 23 and the first bonding layer 21, the lattice defects in the first bonding layer 21 can be reduced compared with the case where the first bonding layer 21 is configured in contact with the n-type contact layer 23. The composition of the fifth layer and the sixth layer can be set, for example, in consideration of the composition or band gap of the n-type contact layer 23, the first bonding layer 21, and the second bonding layer 31. For example, in the case where the n-type contact layer 23, the first bonding layer 21, and the second bonding layer 31 are composed of GaN layers, the fifth layer can be composed of a GaN layer, and the sixth layer can be composed of an InGaN layer. In addition, in the case where the n-type contact layer 23, the first bonding layer 21, and the second bonding layer 31 are composed of GaN layers, the fifth layer and the sixth layer can also be composed of an InGaN layer, so that the In composition ratio of the fifth layer and the sixth layer is different.

[0128] The third superlattice layer 22 may contain n-type impurities. By making the third superlattice layer 22 contain n-type impurities, electrons can be effectively supplied from the n-type contact layer 23 to the first bonding layer 21. When the third superlattice layer 22 contains n-type impurities, either or both of the fifth and sixth layers may contain n-type impurities. When the third superlattice layer 22 contains n-type impurities, the n-type impurity concentration of the third superlattice layer 22 is preferably 1×10 19 cm -3 For example, in the nitride semiconductor device of Embodiment 4-2, the n-type impurity concentration of the third superlattice layer 22 is preferably lower than the n-type impurity concentration of the second superlattice layer. Here, the n-type impurity concentration of the third superlattice layer 22 refers to the average value of the n-type impurity concentration of the entire third superlattice layer 22 .

[0129] The thickness of the third superlattice layer 22 is preferably as thin as possible relative to the first bonding layer 21 and the second bonding layer 31 as long as the desired defect reduction effect can be obtained. For example, the thickness of the third superlattice layer 22 is preferably thinner than the thickness of the first superlattice layer 40. By reducing the thickness of the third superlattice layer 22, it is possible to perform well the injection of carriers into the first p-type semiconductor layer 30 via the tunnel junction without reducing the thickness.

[0130] That is, when the third superlattice layer 22 is configured, it is possible to form a V-shaped pit starting from the superlattice layer. Even if the V-shaped pit is formed, the reduction in carrier injection into the first p-type semiconductor layer 30 due to the formation of the V-shaped pit can be suppressed by thinning the third superlattice layer 22.

[0131] Specifically, when the third superlattice layer 22 is configured thicker and a V-shaped pit is formed starting from the third superlattice layer 22, the influence of the V-shaped pit formed in the third superlattice layer 22 becomes larger, the flatness of the tunnel bonding interface is reduced, and it is difficult to efficiently obtain the tunnel effect. That is, in order to efficiently obtain the tunnel effect, a certain level of flatness is required at the tunnel bonding interface. If the tunnel bonding interface does not have this certain level of flatness, the tunnel effect is reduced. Therefore, in order to efficiently obtain the tunnel effect, even if a V-shaped pit is formed starting from the third superlattice layer 22, it is necessary to suppress the influence of the V-shaped pit so as to ensure a certain level of flatness at the tunnel bonding interface. For this reason, it is preferred to make the thickness of the third superlattice layer 22 thinner.

[0132] As described above, for example, the thickness of the third superlattice layer 22 is preferably thinner than the thickness of the first superlattice layer 40. For example, the thickness of the third superlattice layer 22 can be changed by adjusting the thickness of the fifth layer and the thickness of the sixth layer, respectively, and adjusting the number of pairs including the fifth layer and the sixth layer.

[0133] For example, the first superlattice layer 40 includes n pairs including the first layer 41 and the second layer 42, and the third superlattice layer 22 includes m pairs including the fifth layer and the sixth layer. Here, n and m are integers greater than 1. For example, the thickness of the first layer 41 of the first superlattice layer 40 and the thickness of the fifth layer of the third superlattice layer 22 can be greater than 1 nm and less than 3 nm. The thickness of the second layer 42 of the first superlattice layer 40 and the thickness of the sixth layer of the third superlattice layer 22 can be greater than 0.5 nm and less than 1.5 nm. For example, the number of pairs n in the first superlattice layer 40 can be set to greater than 16 and less than 60, and the number of pairs m in the third superlattice layer 22 can be set to greater than 3 and less than 15. Within the above-mentioned range of thickness and range of pairs, the thickness of the first superlattice layer 40 and the third superlattice layer 22 can be adjusted respectively, so that the thickness of the third superlattice layer 22 is thinner than the thickness of the first superlattice layer 40.

[0134] For example, the first layer 41 and the fifth layer are made to have the same thickness, the second layer 42 and the sixth layer are made to have the same thickness, and the number of logarithms m of the third superlattice layer 22 is made smaller than the number of logarithms n of the first superlattice layer 40. Thus, the thickness of the third superlattice layer 22 can be made thinner than the thickness of the first superlattice layer 40.

[0135] In addition, when the first layer 41 of the first superlattice layer 40 and the fifth layer of the third superlattice layer 22 are set as GaN layers, and the second layer 42 of the first superlattice layer 40 and the sixth layer of the third superlattice layer 22 are set as InGaN layers, for example, the thickness of the first layer 41 and the fifth layer composed of GaN layers is made thicker than the thickness of the second layer 42 and the sixth layer.

[0136] (First bonding layer 21)

[0137] The first bonding layer 21 is, for example, 8×10 19 cm -3 Above and 8×10 20 cm -3 The nitride semiconductor layer doped with the n-type impurity at a relatively high concentration is a layer that forms a tunnel junction with the second bonding layer 31. The n-type impurity concentration of the first bonding layer 21 is higher than the n-type impurity concentration of the n-type contact layer 23.

[0138] The thickness of the first bonding layer 21 is, for example, not less than 1 nm and not more than 10 nm. The first bonding layer 21 may contain In. When the first bonding layer 21 contains In, the band gap of the first bonding layer 21 can be reduced, and the tunnel effect can be easily obtained.

[0139] In addition, the first bonding layer 21 may include more than two layers, for example, a GaN layer and an InGaN layer. For example, it may include a GaN layer disposed on the n-type contact layer 23 side and having a thickness of 1 nm or more and 10 nm or less, and an InGaN layer having a thickness of 0.5 nm or more and 5 nm or less. The In composition ratio of the InGaN layer is, for example, 1% or more and 6% or less.

[0140] <First p-type semiconductor layer 30 >

[0141] In the nitride semiconductor light emitting element of the fourth embodiment, the first p-type semiconductor layer 30 includes the second bonding layer 31 and the third p-type semiconductor layer 32 in this order from the substrate 10 side.

[0142] (Second Bonding Layer 31)

[0143] The second bonding layer 31 is, for example, 8×10 19 cm -3 Above and 8×10 20 cm -3 The following nitride semiconductor layer doped with p-type impurities at a relatively high concentration is a layer that forms a tunnel junction with the first bonding layer 21. The p-type impurity concentration of the second bonding layer 31 is higher than the p-type impurity concentration of the third p-type semiconductor layer 32 described later.

[0144] The thickness of the second bonding layer 31 is, for example, not less than 1 nm and not more than 30 nm. In addition, the second bonding layer 31 may include two or more layers each containing p-type impurities at a higher concentration than the third p-type semiconductor layer 32. The second bonding layer 31 may include, for example, 8×10 19 cm -3 Above and 8×10 20 cm -3A p-type GaN layer with a thickness of 1 nm to 10 nm and doped with Mg at a concentration lower than that of the p-type GaN layer (wherein 8×10 19 cm -3 Above and 3×10 20 cm -3 A p-type GaN layer doped with Mg (within a concentration range of 10 to 20 nm) and having a thickness of not less than 10 nm and not more than 20 nm.

[0145] (Third p-type semiconductor layer 32)

[0146] The third p-type semiconductor layer 32 is a nitride semiconductor layer including p-type impurities disposed on the second bonding layer 31. The p-type impurity concentration of the third p-type semiconductor layer 32 is preferably 1×10 18 cm -3 Above and 1×10 19 cm -3 The following, for example, can be obtained by taking 1×10 18 cm -3 Above and 1×10 19 cm -3 The following is a p-type GaN layer composition containing Mg as a p-type impurity.

[0147] The nitride semiconductor light emitting device according to the embodiment of the present disclosure includes the following aspects, for example.

[0148] [Method 1]

[0149] A nitride semiconductor light-emitting element, comprising:

[0150] a first n-type semiconductor layer;

[0151] a first p-type semiconductor layer, which is disposed on the first n-type semiconductor layer and is in contact with the first n-type semiconductor layer;

[0152] A first superlattice layer, which is disposed on the first p-type semiconductor layer and contains p-type impurities;

[0153] an active layer disposed on the first superlattice layer;

[0154] A second n-type semiconductor layer, disposed on the active layer;

[0155] a first electrode electrically connected to the first n-type semiconductor layer;

[0156] A second electrode is electrically connected to the second n-type semiconductor layer.

[0157] [Method 2]

[0158] The nitride semiconductor light emitting device according to embodiment 1, wherein

[0159] The first superlattice layer is formed by alternately stacking a first layer and a second layer having a lattice constant different from that of the first layer.

[0160] The first layer contains In and p-type impurities.

[0161] [Method 3]

[0162] A nitride semiconductor light emitting device according to embodiment 2, wherein:

[0163] The second layer contains In and p-type impurities,

[0164] The p-type impurity concentration of the second layer is lower than the p-type impurity concentration of the first layer,

[0165] The In composition ratio of the second layer is smaller than the In composition ratio of the first layer.

[0166] [Method 4]

[0167] A nitride semiconductor light emitting device according to Embodiment 3, wherein:

[0168] The p-type impurity concentration of the first layer is lower than the p-type impurity concentration of the first p-type semiconductor layer.

[0169] [Method 5]

[0170] The nitride semiconductor light-emitting device according to any one of aspects 2 to 4, wherein

[0171] The p-type impurity concentration of the first layer is 1×10 18 cm -3 Above and 3×10 19 cm -3 the following.

[0172] [Method 6]

[0173] The nitride semiconductor light-emitting device according to any one of aspects 2 to 5, wherein

[0174] The thickness of the first layer is thinner than that of the second layer.

[0175] [Method 7]

[0176] The nitride semiconductor light emitting device according to any one of aspects 1 to 6, further comprising:

[0177] a second active layer, disposed on the second n-type semiconductor layer;

[0178] a second p-type semiconductor layer, disposed on the second active layer;

[0179] A third electrode is electrically connected to the second p-type semiconductor layer.

[0180] [Method 8]

[0181] A nitride semiconductor light emitting device according to embodiment 7, wherein:

[0182] The invention further includes a second superlattice layer disposed between the second n-type semiconductor layer and the second active layer.

[0183] [Method 9]

[0184] A nitride semiconductor light emitting device according to Embodiment 8, wherein:

[0185] The second superlattice layer is formed by alternately stacking a third layer and a fourth layer having a lattice constant different from that of the third layer.

[0186] The third layer and the fourth layer are undoped layers.

[0187] [Method 10]

[0188] The nitride semiconductor light emitting device according to embodiment 8 or 9, wherein

[0189] The second superlattice layer is formed by alternately stacking a third layer and a fourth layer having a lattice constant different from that of the third layer.

[0190] The third layer includes n-type impurities.

[0191] [Method 11]

[0192] The nitride semiconductor light-emitting device according to any one of aspects 8 to 10, wherein

[0193] The third layer contains In.

[0194] [Method 12]

[0195] A nitride semiconductor light emitting device according to embodiment 11, wherein:

[0196] The n-type impurity concentration of the fourth layer is lower than the n-type impurity concentration of the third layer,

[0197] The In composition ratio of the fourth layer is smaller than the In composition ratio of the third layer.

[0198] [Method 13]

[0199] The nitride semiconductor light-emitting device according to any one of aspects 9 to 12, wherein

[0200] The thickness of the third layer is thinner than that of the fourth layer.

[0201] [Method 14]

[0202] The nitride semiconductor light-emitting device according to any one of aspects 1 to 4, wherein

[0203] The first n-type semiconductor layer includes a third superlattice layer and a first bonding layer disposed on the third superlattice layer and connected to the first p-type semiconductor layer.

[0204] The first p-type semiconductor layer includes a second bonding layer that is tunnel-bonded to the first bonding layer.

[0205] [Method 15]

[0206] A nitride semiconductor light emitting device according to embodiment 14, wherein:

[0207] The thickness of the third superlattice layer is thinner than that of the first superlattice layer.

[0208] [Method 16]

[0209] The nitride semiconductor light emitting device according to embodiment 14 or 15, wherein

[0210] The third superlattice layer includes n-type impurities.

[0211] [Method 17]

[0212] The nitride semiconductor light emitting device according to any one of aspects 14 to 16, further comprising:

[0213] A second superlattice layer, which is disposed on the second n-type semiconductor layer and includes n-type impurities;

[0214] a second active layer disposed on the second superlattice layer;

[0215] a second p-type semiconductor layer, disposed on the second active layer;

[0216] a third electrode electrically connected to the second p-type semiconductor layer,

[0217] The n-type impurity concentration of the third superlattice layer is lower than the n-type impurity concentration of the second superlattice layer.

[0218] Description of Reference Numerals

[0219] 1: The first light-emitting part

[0220] 2: Second light-emitting part

[0221] 10: Substrate

[0222] 11: First electrode

[0223] 12: Second electrode

[0224] 13: The third electrode

[0225] 13a: Pad electrode

[0226] 13b: Electrode layer

[0227] 20: First n-type semiconductor layer

[0228] 21: First bonding layer

[0229] 22: The third superlattice layer

[0230] 23: n-type contact layer

[0231] 30: First p-type semiconductor layer

[0232] 31: Second bonding layer

[0233] 32: The third p-type semiconductor layer

[0234] 40: First superlattice layer

[0235] 50: First active layer

[0236] 60: Second n-type semiconductor layer

[0237] 70: Second active layer

[0238] 80: Second p-type semiconductor layer

[0239] 90: Second superlattice layer.

Claims

1. A nitride semiconductor light emitting element, characterized in that: include: a first n-type semiconductor layer; a first p-type semiconductor layer, which is disposed on the first n-type semiconductor layer and is in contact with the first n-type semiconductor layer; A first superlattice layer, which is disposed on the first p-type semiconductor layer and contains p-type impurities; an active layer disposed on the first superlattice layer; A second n-type semiconductor layer, disposed on the active layer; a first electrode electrically connected to the first n-type semiconductor layer; A second electrode is electrically connected to the second n-type semiconductor layer.

2. The nitride semiconductor light emitting element according to claim 1, wherein: The first superlattice layer is formed by alternately stacking a first layer and a second layer having a lattice constant different from that of the first layer. The first layer includes In and p-type impurities.

3. The nitride semiconductor light emitting element according to claim 2, wherein: The second layer contains In and p-type impurities, The p-type impurity concentration of the second layer is lower than the p-type impurity concentration of the first layer, The In composition ratio of the second layer is smaller than the In composition ratio of the first layer.

4. The nitride semiconductor light emitting element according to claim 3, wherein: The p-type impurity concentration of the first layer is lower than the p-type impurity concentration of the first p-type semiconductor layer.

5. The nitride semiconductor light emitting device according to any one of claims 2 to 4, wherein The p-type impurity concentration of the first layer is 1×10 18 cm -3 Above and 3×10 19 cm -3 the following.

6. The nitride semiconductor light emitting device according to any one of claims 2 to 4, wherein The thickness of the first layer is thinner than that of the second layer.

7. The nitride semiconductor light emitting device according to any one of claims 1 to 4, wherein Also includes: a second active layer, disposed on the second n-type semiconductor layer; a second p-type semiconductor layer, disposed on the second active layer; A third electrode is electrically connected to the second p-type semiconductor layer.

8. The nitride semiconductor light emitting element according to claim 7, wherein: The invention further includes a second superlattice layer disposed between the second n-type semiconductor layer and the second active layer.

9. The nitride semiconductor light emitting element according to claim 8, wherein: The second superlattice layer is formed by alternately stacking a third layer and a fourth layer having a lattice constant different from that of the third layer. The third layer and the fourth layer are undoped layers.

10. The nitride semiconductor light emitting element according to claim 8, wherein: The second superlattice layer is formed by alternately stacking a third layer and a fourth layer having a lattice constant different from that of the third layer. The third layer includes n-type impurities.

11. The nitride semiconductor light emitting element according to claim 10, wherein: The third layer contains In.

12. The nitride semiconductor light emitting element according to claim 11, wherein: The n-type impurity concentration of the fourth layer is lower than the n-type impurity concentration of the third layer, The In composition ratio of the fourth layer is smaller than the In composition ratio of the third layer.

13. The nitride semiconductor light emitting element according to claim 10, wherein: The thickness of the third layer is thinner than that of the fourth layer.

14. The nitride semiconductor light emitting device according to any one of claims 1 to 4, wherein The first n-type semiconductor layer includes a third superlattice layer and a first bonding layer disposed on the third superlattice layer and connected to the first p-type semiconductor layer. The first p-type semiconductor layer includes a second bonding layer that is tunnel-bonded to the first bonding layer.

15. The nitride semiconductor light emitting element according to claim 14, wherein: The thickness of the third superlattice layer is thinner than that of the first superlattice layer.

16. The nitride semiconductor light emitting element according to claim 14, wherein: The third superlattice layer includes n-type impurities.

17. The nitride semiconductor light emitting element according to claim 16, wherein: Also includes: A second superlattice layer, which is disposed on the second n-type semiconductor layer and includes n-type impurities; a second active layer disposed on the second superlattice layer; a second p-type semiconductor layer, disposed on the second active layer; a third electrode electrically connected to the second p-type semiconductor layer, The n-type impurity concentration of the third superlattice layer is lower than the n-type impurity concentration of the second superlattice layer.

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