JP5948767B2 - Nitride semiconductor light emitting device - Google Patents

Description

  The present invention relates to a light emitting diode (LED), a laser diode, a solar cell, a photosensor, and a nitride semiconductor device such as a transistor.

  A semiconductor light emitting device (LED) has a resistivity as small as possible and a current flows as efficiently as possible except for a portion where it is necessary to intentionally increase the electrical resistance in the semiconductor device in order to effectively use the supplied electric energy. It is desirable to reduce the forward voltage by using a structure, which can improve the luminous efficiency of the LED. In order to reduce the electrical resistance of the semiconductor, it is possible to increase the cross-sectional area through which a current flows or to decrease the resistivity by doping a large amount of impurities.

  In general, the P-type semiconductor layer is designed so that the current flow distance is shortened because the resistivity is originally high. On the other hand, in an N-type semiconductor layer that plays a major role in current diffusion, high-concentration impurity doping or growth on an insulator substrate is performed so that the positive electrode (p electrode) and the negative electrode (n electrode) are on the same side. In an LED having a structure in which a current flows through the N-type semiconductor layer laterally, the resistance is lowered by increasing the thickness of the N-type semiconductor layer.

  In addition, in conventional GaN-based LED elements by MOCVD, for example, as shown in Patent Document 1, etc., InGaN is used for the light emitting layer (active layer), and InGaN or GaN is doped with Si in the N-type semiconductor layer. Things are used.

JP 2000-216433 A

However, if a large amount of Si is doped in order to reduce the resistance of the N-type semiconductor layer, problems such as pits and cracks are likely to occur during the growth, so there is a limit to the amount of Si doping and the film thickness is also limited. there were.
Therefore, the conventional nitride semiconductor device cannot sufficiently reduce the resistance on the n side and cannot sufficiently reduce the forward voltage.

  Therefore, an object of the present invention is to provide a nitride semiconductor device capable of lowering the forward voltage as compared with the prior art.

  In order to achieve the above object, a nitride semiconductor light emitting device according to the present invention includes an n-side nitride semiconductor layer, an active layer, and a p-side nitride semiconductor layer including an n-side contact layer made of GaN doped with Si. The n-side nitride semiconductor layer has an AlxGa1-xN (1> x> 0) layer having a higher Si impurity concentration than the n-side contact layer.

  According to the nitride semiconductor light emitting device of the present invention configured as described above, the n-side nitride semiconductor layer has an AlxGa1-xN (1> x> 0) having a higher Si impurity concentration than the n-side contact layer. Since it has a layer, it is possible to provide a nitride semiconductor device having a forward voltage lower than that of the prior art.

It is sectional drawing of the nitride semiconductor light-emitting device of embodiment which concerns on this invention. It is sectional drawing of the nitride semiconductor light-emitting device of the 1st modification concerning this invention. It is sectional drawing of the nitride semiconductor light-emitting device of the 2nd modification concerning this invention. It is the graph which evaluated the presence or absence of a pit with respect to impurity concentration and Al mixed crystal ratio. It is a graph which shows the forward voltage (Vf) with respect to forward current (If) about the nitride semiconductor element of Example 1 which concerns on this invention. It is a graph which shows the forward voltage (Vf) with respect to forward current (If) about the nitride semiconductor element of Example 2 which concerns on this invention. It is a graph which shows the forward voltage (Vf) with respect to the forward current (If) about the nitride semiconductor element of Example 3 which concerns on this invention. It is sectional drawing of the nitride semiconductor light-emitting device of a comparative example.

A nitride semiconductor light emitting device according to an embodiment of the present invention will be described below with reference to the drawings.
<Embodiment>
A nitride semiconductor light emitting device according to an embodiment of the present invention includes an n-side nitride semiconductor layer including an n-side contact layer made of Si-doped GaN, an active layer, and a p-side nitride semiconductor layer. The n-side nitride semiconductor layer has an AlxGa1-xN (1>x> 0) layer having a higher Si impurity concentration than the n-side contact layer.

In FIG. 1, as one example of the embodiment according to the present invention, n ⁺ Al x Ga 1-x N (1>x> 0 is in contact with the lower surface of the n-side contact layer 4 and has a higher Si impurity concentration than the n-side contact layer 4. ) Shows a nitride semiconductor light emitting device in which a layer 13 is formed.
In the present specification, the lower surface means a surface closer to the substrate, and the upper surface means a surface far from the substrate.

In the nitride semiconductor light emitting device shown in FIG. 1, the buffer layer 2 is made of AlGaN, and the n-side nitride semiconductor layer is an undoped GaN layer 3 and an n ⁺ AlxGa1-xN (1>x> 0) layer from the substrate 2 side. 13, an n-side contact layer 4 made of Si-doped GaN, an n-side GaN composite layer 6, and a superlattice buffer layer 7. The active layer 8 has, for example, a multiple quantum well structure in which well layers and barrier layers are alternately and repeatedly stacked. The p-side nitride semiconductor layer includes a p-side cladding layer 9 and a p-side contact layer 10. . Further, the n-side contact layer 4, the p-side nitride semiconductor layer, the active layer 8, the superlattice buffer layer 7, and the n-side GaN composite layer 6 are partially removed to expose the upper surface. An n-electrode 5 is formed, for example, a transparent P-contact electrode 11 is formed on the upper surface of the P-side contact layer 10, and a p-pad electrode 12 is formed on the P-contact electrode 11.

In the nitride semiconductor light emitting device of the embodiment configured as described above, in the n-side nitride semiconductor layer, n ⁺ AlxGa1-xN (1>x> 0 having a lower Si impurity concentration than the n-side contact layer 4). ) Layer 13, the resistance of the n-side nitride semiconductor layer can be lowered, and the forward voltage can be lowered.
The reason will be specifically described below.
In the present specification, the n ⁺ AlxGa1-xN (1>x> 0) layer 13 may be referred to as an n ⁺ AlGaN layer 13.

FIG. 8 is a cross-sectional view of a nitride semiconductor light emitting device of a comparative example that does not include the n ⁺ AlGaN layer 13. The nitride semiconductor light emitting device of this comparative example is configured similarly to the nitride semiconductor light emitting device of the embodiment of FIG. 1 except that the n ⁺ AlGaN layer 13 is not provided. Similar elements are denoted by the same reference numerals.

  Further, in the nitride semiconductor light emitting device of the comparative example, the n-side contact layer 4 is made of GaN doped with Si, and the Si doping amount (impurity concentration) and film thickness are the resistance values of the entire n-side contact layer 4. It is set to be smaller. That is, as explained in the background art, if a large amount of Si is doped to reduce the resistance of the N-type semiconductor layer, pits and cracks are likely to occur during the growth, so there is a limit to the amount of Si doping. The film thickness is also limited. Therefore, considering both of them, the Si doping amount and the film thickness are set so that the resistance value of the entire n-side contact layer 4 becomes small. Therefore, there has been a certain limit in reducing the resistance value of the entire n-side semiconductor layer. In general, in the case of a nitride semiconductor light-emitting device capable of emitting visible light, it is usually GaN in the n-side contact layer because the crystallinity of binary mixed crystal GaN is better than that of ternary mixed crystal AlGaN. Is used.

In contrast, the present invention focuses on the fact that an AlGaN layer in which a part of Ga is replaced with Al can be doped with a relatively large amount of Si without generating pits and cracks compared to GaN. In this structure, an n ⁺ AlGaN layer 13 is provided separately from the n-side contact layer 4 in the n-side semiconductor layer.

  FIG. 4 shows the occurrence of pits with respect to the Si impurity concentration of the GaN and AlGaN layers. The presence or absence of this pit was evaluated by surface observation when a Si-doped GaN layer and an AlGaN layer were grown on the sapphire substrate via an undoped GaN layer.

As shown in FIG. 4, in the AlGaN layer, for example, when the Al mixed crystal ratio is 0.01, pits are generated when the Si impurity concentration is 1.5 × 10 ¹⁹ atoms / cm ³ or more in GaN. On the other hand, even if the Si impurity concentration is 4.5 × 10 ¹⁹ atoms / cm ³ , no pits are generated. Therefore, it can be understood that the AlGaN layer can have a Si impurity concentration three times or more that of the GaN layer without generating pits, and can have a low resistance.

Thus, since the AlGaN layer can have a Si impurity concentration three times or more that of the GaN layer without generating pits and can have a low resistance, the current path of the n-side contact layer 4 and the n ⁺ AlGaN layer 13 can be reduced. The resistance can be reduced as compared with the comparative example in which the current path is formed only by the n-side contact layer 4. Furthermore, by providing the n ⁺ AlGaN layer 13, the current can be easily spread in the lateral direction, and high-density current can be prevented from flowing locally. As a result, the forward voltage of the nitride semiconductor light emitting device can be lowered.

In the present invention, the low resistance n ⁺ AlGaN layer 13 is preferably ８ or more of the total thickness of the entire n-side contact layer 4. This is because the effect of lowering the resistance of the n-side semiconductor layer becomes smaller as the thickness is thinner.

As described above, the present invention uses the fact that the AlGaN layer can be doped with Si impurities at a higher concentration than the GaN layer and can have a low resistance, so that the current path combining the n-side contact layer 4 and the n ⁺ AlGaN layer 13 is used. Is to lower the resistance. Therefore, the present invention is not limited to the case where the n ⁺ AlGaN layer 13 is provided in contact with the lower surface of the n-side contact layer 4, and the AlxGa1-xN (1>x> 0) layer is at least n-side nitrided. If it exists in an oxide semiconductor layer, the resistance of an n side nitride semiconductor layer can be made low. The AlxGa1-xN (1>x> 0) layer may be on either side of the n-side contact layer, that is, between the active layer 8 and the n-side contact layer 4, or between the n-side contact layer 4 and the substrate 1. (The n-side contact layer may be between the AlGaN layer and the active layer). However, in the present invention, the AlxGa1-xN (1>x> 0) layer 13 preferably has a short distance from the n electrode. Therefore, more preferably, the AlxGa1-xN (1>x> 0) layer 13 is in contact with the upper surface or the lower surface of the n-side contact layer 4.
When the n ⁺ AlGaN layer 13 is below the n-side contact layer 4, current may not reach the n ⁺ AlGaN layer 13 if another layer is interposed therebetween. Therefore, in this case, it is preferable that the n-side contact layer 4 and the n ⁺ AlGaN layer 13 are in contact with each other.
FIG. 2 shows an example in which the n ⁺ AlGaN layer 13 is closer to the n electrode 5 as compared with FIG. 1. In FIG. 3, the n ⁺ AlGaN layer 13 is formed in contact with the upper surface of the n-side contact layer 4. An example is shown. In the example shown in FIG. 2, for example, a base layer 14 having the same composition as that of the n-side contact layer 4 is provided in contact with the substrate side of the n ⁺ AlGaN layer 13.
As described above, since the n ⁺ AlGaN layer 13 can be formed at various positions, it can be formed at an appropriate position according to the purpose.

For example, in the case of a structure in which the p-type electrode and the n-type electrode are taken from the same side while leaving the substrate, the n ⁺ AlGaN layer 13 is formed on and in contact with the n-side contact layer 4 (between the active layer). As a result, the effect of reducing the forward voltage is further increased. Further, in the case where the crystallinity of the active layer formed on the upper layer is kept high and importance is attached to the decrease in light output during high temperature operation, the position of the n ⁺ AlGaN layer 13 should be provided in contact with the lower surface of the n-side contact layer. Even in such a case, the effect of reducing the forward voltage can be obtained.

  As described above, according to the nitride semiconductor light emitting device according to the present invention, the forward voltage can be reduced, and the light emission efficiency of the semiconductor light emitting device can be improved. In particular, in a high current operation in which the power loss in the n-side layer increases, the power loss in the n-side layer increases in proportion to the square of the input current, so that the forward voltage reduction effect and the light emission efficiency reduction effect are large. .

  Hereinafter, each layer in the nitride semiconductor light emitting device of the embodiment will be described.

<Buffer layer>
The buffer layer 2 is a layer that relieves stress due to strain caused by a difference in lattice constant between the substrate 1 and the nitride semiconductor layer, and is made of, for example, AlxGa1-xN (0 <x ≦ 1).
In addition to AlxGa1-xN, for example, AlN can also be used.

<Undoped GaN layer 3>
The undoped GaN layer 3 is a pit buried layer for reducing pits generated in the buffer layer, and is formed to a thickness of 3 μm, for example.

<N ⁺ AlxGa1-xN (1>x> 0) Layer 13>
As described above, the n ⁺ AlGaN layer 13 forms a current path that diffuses current in the lateral direction on the n side together with the n-side contact layer 4, and reduces the resistance of the entire current path. The Al mixed crystal ratio is preferably set to 0.03 ≧ x> 0, more preferably 0.02 ≧ x ≧ 0.005. When the Al mixed crystal ratio becomes too high, the crystallinity is lowered and the in-plane composition distribution of Al deteriorates to generate a portion where Al is insufficient. When the Al mixed crystal ratio is too low, the effect of suppressing the generation of pits is generated. Decreases. Considering these, the most preferable Al mixed crystal ratio is about 0.01. The film thickness of the n ⁺ AlGaN layer 13 is thinner and the effect of lowering the overall resistance n-side semiconductor layer is reduced, in order to warp of the wafer in the reaction there is a problem such as large as thick, n ⁺ AlGaN layer The film thickness t is set in the range of 3.0 μm ≧ t ≧ 0.05 μm, more preferably 2 μm ≧ t ≧ 1 μm.
The Si impurity concentration is higher than that of the n-side contact layer 4 and is preferably in the range of 1.18 × 10 ¹⁹ atoms / cm ^{3 to} 5.6 × 10 ¹⁹ atoms / cm ³ , more preferably 2 It is set in the range of × 10 ¹⁹ atoms / cm ³ to 4 × 10 ¹⁹ atoms / cm ³ .

The n ⁺ AlGaN layer 13 is formed by MOCVD (metal organic vapor phase epitaxy), but in order to make the film thickness uniform, the carrier gas H ₂ is about twice as large as when GaN is grown. It is desirable to flow. The Al source gas is, for example, TMA, and the Al mixed crystal ratio can be adjusted by the flow rate. Furthermore, in order to improve the Al in-plane composition distribution, it is desirable that the growth rate of the n ⁺ AlGaN layer 13 be about 30 nm / min. The Si impurity concentration is adjusted by the flow rate ratio of the Si source gas.

<N-side contact layer 4>
The n-side contact layer 4 is a layer where the n-electrode 5 is formed. The n-side contact layer 4 is preferably made of GaN doped with Si in order to achieve good ohmic contact with the n-electrode, and the Si impurity concentration is preferably higher, but it is relatively thick to suppress the generation of pits. In order to form, it is preferably set in the range of 8 × 10 ¹⁸ atoms / cm ^{3 to} 1.32 × 10 ¹⁹ atoms / cm ³ . The film thickness of the n-side contact layer 4 is preferably 1 μm or more.

<N-side GaN composite layer 6>
The n-side GaN composite layer 6 is a layer formed in order to obtain a low forward voltage and a high breakdown voltage characteristic. For example, a composite film in which an undoped GaN layer, a Si-doped GaN layer, and an undoped GaN layer are sequentially stacked can be formed. Although the individual film thickness constituting the composite film is not limited, 5 to 500 nm is suitable, and preferably 5 to 300 nm.

<Superlattice buffer layer 7>
The superlattice buffer layer 7 is a buffer layer between the active layer and the GaN layer formed below the superlattice buffer layer 7. For example, a multilayer film composed of a GaN layer and an InGaN layer can be used. The entire multilayer film may be undoped, or only GaN may be doped with Si. The individual film thicknesses constituting the multilayer film are not limited, but 1 to 5 nm is suitable.

<Active layer 8>
The active layer 8 has, for example, a multiple quantum well structure in which well layers and barrier layers are alternately and repeatedly stacked. For example, the In layer has a mixed crystal ratio of In depending on light having a desired emission wavelength. Made of InGaN. The barrier layer is made of InGaN, GaN, or a composition containing Al in them, which has a smaller In mixed crystal ratio than the well layer.

<P-side cladding layer 9>
The p-side cladding layer 9 is a p-side barrier layer that blocks electrons. For example, the p-side cladding layer 9 is made of Mg-doped AlyGa1-yN (1 ≧ y ≧ 0) with a thickness of 10 to 30 nm.

<P-side contact layer 10>
The p-side contact layer 10 is a layer on which the p-contact electrode 11 is provided, and is made of, for example, an Mg-doped GaN layer.

<N electrode 5>
The n electrode 5 is an electrode that makes ohmic contact with the n-side contact layer 4. The material of the n-electrode is not limited. For example, it can be a three-layer structure of Ti / Rh / Au from the n-side contact layer 4 side.

<P contact electrode 11>
The p contact electrode 11 is made of, for example, a transparent electrode such as ITO, and light is emitted through the P contact electrode 11.

<P pad electrode 12>
The p-pad electrode 12 is not limited, but can be made of the same material as the n-electrode, that is, a three-layer structure of Ti / Rh / Au from the n-side contact layer 4 side, from the viewpoint of shortening the electrode formation process.
Each of the nitride semiconductor light emitting devices shown in FIGS. 1 to 3 is an example in which a p-type electrode and an n-type electrode are formed on the same surface side, and both electrodes are connected from the same direction. Although shown, the present invention is not limited to this, and can be applied to a nitride semiconductor light emitting device in which a p-type electrode is formed on the upper surface of the device and an n-type electrode is formed on the lower surface of the device. be able to.

Next, examples according to the present invention will be described.
Example 1.
In Example 1, for example, a 1 mm square nitride semiconductor light emitting device used for a headlight was manufactured as follows.

In Example 1, first, an AlGaN buffer layer 2 having a thickness of 20 μm and an undoped GaN layer 3 having a thickness of 3 μm were formed on a substrate 1 made of sapphire.
Next, the following layers constituting the n-side nitride semiconductor layer were grown in order on the undoped GaN layer 3.
(1) n ⁺ AlGaN layer 13:
In Example 1, the Al mixed crystal ratio x of the n ⁺ AlGaN layer 13 was set to 0.01, and the Si impurity concentration was set to 3.4 × 10 ¹⁹ atoms / cm ³ .
Here, the growth rate of the n ⁺ AlGaN layer 13 was set to a relatively low 30 nm / min and was grown to a thickness of 1 μm.
(2) n-side contact layer 4:
The n-side contact layer 4 was made of Si-doped GaN having a film thickness of 3 μm, and the Si impurity concentration was adjusted to be 1.0 × 10 ¹⁹ atoms / cm ³ .
(3) n-side GaN composite layer 6:
The n-side GaN composite layer 6 has a three-layer structure in which a 0.3 μm undoped GaN layer, a 0.03 μm trace amount Si-doped GaN layer, 0.005 μm and undoped GaN are grown in this order.
(4) Superlattice buffer layer 7:
The superlattice buffer layer 7 is the last layer of the n-side nitride semiconductor layer, and repeats a 5 nm GaN layer, a 4 nm undoped GaN layer, and a 2 nm undoped In _0.1 Ga _0.9 N layer in that order so that each becomes 20 layers. Laminated.

Next, the active layer 8 was formed on the n-side nitride semiconductor layer (superlattice buffer layer 7).
The active layer 8 has a multi-quantum well structure in which an undoped GaN barrier layer with a thickness of 4 nm and an In _0.3 Ga _0.7 N well layer with a thickness of 3 nm are alternately and repeatedly stacked in layers of nine layers, and finally the barrier layer is stacked. did.

Next, the following layers constituting the p-side nitride semiconductor layer were grown in order on the active layer 8.
(5) p-side cladding layer (p-side barrier layer) 9:
As the p-side cladding layer, an Mg-doped Al _0.1 Ga _0.9 N layer having a thickness of 12 nm was formed. The Mg impurity concentration of the p-side cladding layer was 1 × 10 ²⁰ atoms / cm ³ .
(6) p-side contact layer 10:
As a p-side contact layer, an undoped GaN layer with a film thickness of 32 nm, a GaN layer with a film thickness of 32 nm and an Mg impurity concentration of 1 × 10 ²⁰ atoms / cm ³ and an Mg impurity concentration of 15 nm with an impurity concentration of 5 × 10 ²⁰ atoms / cm ³ A GaN layer was formed in order.
After forming this p-side contact layer, the p-side nitride semiconductor layer was reduced in resistance by heat treatment (600 ° C.) in an N ₂ and O ₂ atmosphere.

Next, in order to make an electrical connection from the upper surface to the n-side nitride semiconductor layer, the p-side nitride semiconductor layer and a part of the active layer are removed by etching, and the exposed surface of the n-side contact layer 4 is exposed. An n-electrode 5 was formed.
The n-electrode 5 has a three-layer structure of Ti (1.5 nm) / Rh (200 nm) / Au (500 nm).

Furthermore, ITO having a thickness of 170 nm was formed on the p-side contact layer 10 as a p-contact electrode 11, and a p-pad electrode 12 was formed on the p-contact electrode 11.
The p-pad electrode 12 has a three-layer structure of Ti (1.5 nm) / Rh (200 nm) / Au (500 nm) like the n-electrode 5.

  As described above, the nitride semiconductor light emitting device of Example 1 which is a blue LED having an emission wavelength of about 460 nm was manufactured.

Example 2
In Example 2, a nitride semiconductor light emitting device was fabricated in the same manner as in Example 1 except that the growth rate of the n ⁺ AlGaN layer 13 was set to 75 nm / min.

Comparative Example 1
In Comparative Example 1, Si doped GaN having a Si impurity concentration of 1.0 × 10 ¹⁹ atoms / cm ³ was formed as the n-side contact layer 4 to a thickness of 4 μm without forming the n ⁺ AlGaN layer 13. A 1 mm square nitride semiconductor light emitting device was fabricated in the same manner as in Example 1 except for the above.

The forward voltage (Vf) and power efficiency wall-plug efficiency (WPE) of Examples 1 and 2 and Comparative Example 1 produced as described above were evaluated.
The results are shown in the graphs of FIGS.

Table 1

From the above results, (a) the forward voltage can be lowered by forming the n ⁺ AlGaN layer 13, and (b) the effect of lowering the forward voltage is greater as the growth rate of the n ⁺ AlGaN layer 13 is lower. (C) It can be seen that the larger the forward current, the greater the effect of reducing the forward voltage.

Example 3
In Example 3, a 500 μm × 290 μm nitride semiconductor light emitting device was fabricated as follows.
The semiconductor laminated structure of the nitride semiconductor light emitting device of Example 3 was the same as that of Example 1 except that the film thicknesses of the n ⁺ AlGaN layer 13 and the n-side contact layer 4 were different from those of Example 1. .
In particular,
The n ⁺ AlGaN layer 13 was formed to a thickness of 2 μm so that the Al mixed crystal ratio x was 0.01 and the Si impurity concentration was 3.4 × 10 ¹⁹ atoms / cm ³ .
The n-side contact layer 4 was made of Si-doped GaN having a thickness of 2 μm, and the Si impurity concentration was adjusted to be 1.0 × 10 ¹⁹ atoms / cm ³ .

Comparative Example 2
As Comparative Example 2, the n-side contact layer 4 was formed by growing Si-doped GaN having a Si impurity concentration of 1.0 × 10 ¹⁹ atoms / cm ³ to a thickness of 4 μm without forming the n ⁺ AlGaN layer 13. A nitride semiconductor light emitting device was fabricated in the same manner as in Example 3 except for the above.

The forward voltage (Vf) and power efficiency (WPE) of Example 3 and Comparative Example 2 produced as described above were evaluated.
The results are shown in the graph of FIG.

Table 2

From the above results, also for the medium-sized nitride semiconductor light emitting device, (a) the forward voltage can be lowered by forming the n ⁺ AlGaN layer 13, and (b) the forward voltage is increased as the forward current is increased. It turns out that the effect to reduce is large.

  As described above, according to the nitride semiconductor light emitting device according to the present invention, the forward voltage can be reduced, and the higher the current density, the greater the effect of reducing Vf and increasing the efficiency, so that the power loss can be reduced. . Thereby, since heat generation can be reduced, it is particularly suitable for high-efficiency solid-state lighting applications.

DESCRIPTION OF SYMBOLS 1 Substrate 2 Buffer layer 3 Undoped GaN layer 13 n ⁺ AlGaN layer 4 n side contact layer 5 n electrode 6 n side GaN composite layer 7 superlattice buffer layer 8 active layer 9 p side cladding layer 10 p side contact layer 11 p contact electrode 12 p pad electrode

Claims (6)

An n-side contact layer made of GaN doped with Si and having an Si impurity concentration of 8.0 × 10 ¹⁸ atoms / cm ^{3 to} 1.32 × 10 ¹⁹ atoms / cm ³ , and an Si impurity concentration of 1.18 × 10 6 ^An Al _x Ga _1-x N (1>x> 0) layer that is ¹⁹ atoms / cm ^{3 to} 5.6 × 10 ¹⁹ atoms / cm ³ and is higher than the Si impurity concentration in the n-side contact layer. an n-side nitride semiconductor layer;
An active layer,
a p-side nitride semiconductor layer,
The film thickness t of the Al _x Ga _1-x N (1>x> 0) layer is set in a range of 2.0 μm ≧ t ≧ 1 μm ,
The nitride semiconductor light emitting element in which the Al _x Ga _1-x N (1>x> 0) layer is in contact with the n-side contact layer . The nitride semiconductor light emitting element according to claim 1 , wherein the n-side contact layer is located between the Al _x Ga _1-x N (1>x> 0) layer and the active layer. The nitride semiconductor light emitting device according to claim 1 , wherein the Al _x Ga _1-x N (1>x> 0) layer is located between the n-side contact layer and the active layer. An n-side contact layer made of GaN doped with Si and having an Si impurity concentration of 8.0 × 10 ¹⁸ atoms / cm ^{3 to} 1.32 × 10 ¹⁹ atoms / cm ³ , and an Si impurity concentration of 1.18 × 10 6 ^An Al _x Ga _1-x N (1>x> 0) layer that is ¹⁹ atoms / cm ^{3 to} 5.6 × 10 ¹⁹ atoms / cm ³ and is higher than the Si impurity concentration in the n-side contact layer. an n-side nitride semiconductor layer;
An active layer,
a p-side nitride semiconductor layer,
The film thickness t of the Al _x Ga _1-x N (1>x> 0) layer is set in a range of 2.0 μm ≧ t ≧ 1 μm,
The _{Al x Ga 1-x N (} 1>x> 0) layer, nitride compound semiconductor light-emitting element located between the n-side contact layer and the active layer. The nitride semiconductor according to claim 1, wherein an Al mixed crystal ratio x in the Al _x Ga _1-x N (1>x> 0) layer is set to 0.03 or less. Light emitting element. The Al mixed crystal ratio x in the Al _x Ga _1-x N (1>x> 0) layer is set to a range of 0.02 ≧ x ≧ 0.005, 5. The nitride semiconductor light-emitting device according to one.

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