JP3587699B2 - Semiconductor light emitting device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a semiconductor light emitting device formed by laminating a compound semiconductor crystal on a substrate, and more particularly to a technique for reducing crystal defects on the surface of the lamination and planarizing the same.
[0002]
[Prior art]
A semiconductor light emitting device formed by laminating a compound semiconductor crystal on a substrate has been used in a range from blue to infrared since a lattice mismatched crystal having a crystal lattice length different by 0.5% or more has become available. High-brightness light emission has become possible in a wide wavelength range.
[0003]
For example, a semiconductor light emitting device that emits green light described in US Pat. No. 5,008,718 has a structure as shown in FIG. 11 (hereinafter, referred to as “conventional example 1”). The semiconductor light emitting device 1100 is manufactured by the following procedure.
[0004]
In FIG. 11, on an n-type GaAs temporary substrate (not shown), an n-type InAlGaP first cladding layer 102 lattice-matched to the temporary substrate, a non-doped InAlGaP light emitting layer 103, a p-type InAlGaP second cladding layer 104, and p-type A GaP type window layer 105 is grown. After removing the GaAs temporary substrate (not shown), a transparent substrate layer 109 is grown on the n-type first cladding layer 102 to obtain a semiconductor light emitting device wafer.
[0005]
Next, the n-side electrode 107 is provided on the transparent substrate layer 109. A circular p-side electrode 106 is provided at the center of the electrode forming surface 105a of the window layer 105. The semiconductor wafer 1100 shown in FIG. 11 is manufactured by dividing the wafer into a size of about 300 μm square. Both electrodes 106 and 107 are electrically connected to an external conductor. For example, a metal wire (not shown) having a diameter of about 30 μm connected to an external conductor (not shown) is bonded to the p-side electrode 106.
[0006]
GaP is used for the window layer 105 in order to increase the luminance of the semiconductor light emitting element. GaP has a crystal lattice value about 3.4% smaller than that of the GaAs crystal of the temporary substrate and is a lattice-mismatched crystal. However, since the band gap is sufficiently larger than the band gap of the InAlGaP crystal of the light-emitting layer 103, GaP emits light. The transmittance of the window layer 105 can be kept sufficiently high for light having a wavelength close to the band gap of the light-emitting layer 103 generated in the layer 103. As a result, absorption of light emitted from the light-emitting layer 103 by the window layer 105 can be reduced, and the luminance of the semiconductor light-emitting element can be increased.
[0007]
To increase the luminance of the semiconductor light emitting element, it is also important to reduce the resistance value of the window layer 105. When a current is injected from both electrodes 106 and 107, green light having a wavelength of 560 nm is generated in the light emitting layer 103. When the resistance value of the window layer 105 is high, the current injected from the p-side electrode 106 has a small spread in the horizontal direction, so that light emission is concentrated at a portion of the light-emitting layer 103 facing the p-side electrode 106. Of the light generated in the light-emitting layer 3, light that is substantially perpendicularly incident on the interface between the semiconductor light-emitting element and the outside is efficiently output to the outside of the semiconductor light-emitting element, but other light is reflected at the interface, It does not contribute to the luminance of the semiconductor light emitting device. Therefore, when light emission occurs at a portion of the light emitting layer 103 facing the p-side electrode 106, light that is perpendicularly incident on the boundary surface is also reflected by the p-side electrode 106, and the brightness of the semiconductor light emitting element is reduced.
[0008]
As a method of reducing the resistance value, a method of increasing the p-type impurity concentration of the window layer 105 is well known. However, typical p-type impurities such as Zn (zinc), Mg (magnesium), and Be (beryllium) are substances that easily diffuse in the crystal. The p-type impurity diffuses to this extent, and the conversion efficiency of current into light in the light emitting layer 3 itself decreases, and the luminance of the semiconductor light emitting element decreases.
[0009]
In order to solve such a problem, Japanese Patent Application Laid-Open No. Hei 5-335519 discloses that a window layer has a two-layer structure, a p-type impurity concentration of a window layer close to an active layer is low, and a p-type impurity of a window layer far from the active layer is low. A technique is disclosed in which the concentration is increased so that the current spreads over the entire light emitting layer, and the luminance of the semiconductor light emitting element is prevented from lowering by preventing the p-type impurity from diffusing into the light emitting layer. (Hereinafter, referred to as “Conventional Example 2”).
[0010]
FIG. 12 shows a schematic cross-sectional view of a semiconductor light emitting device 1200 of Conventional Example 2. In the semiconductor substrate 101, the window layer 105 has a two-layer structure, and the first window layer 111 near the active layer and the second window layer 112 far from the active layer constitute the window layer 105.
[0011]
In the semiconductor light emitting device of Conventional Example 2, GaAlAs is used for the window layer 105, but GaAlAs has a narrow band gap and a low transmittance for green light. The present inventors have confirmed that the same effect can be obtained even when the window layer is made of GaP having a large band gap (hereinafter, referred to as a “conventional semiconductor light emitting device”).
[0012]
[Problems to be solved by the invention]
However, when the p-type impurity concentration of GaP used for the window layer is increased, many crystal defects are generated on the p-side electrode formation surface, and the crystal defects cause irregularities on the p-side electrode formation surface. Since the area of the p-side electrode 106 is as small as about 100 μm in diameter, if the p-side electrode formation surface 105a has irregularities, the wafer is divided, and a wire is bonded to the p-side electrode 106 to form a semiconductor light emitting device. There is a problem that the p-side electrode 106 is easily peeled off from the window layer 105.
[0013]
Of the above-mentioned crystal defects, a crystal defect called a hillock is most important. The hillock defect is a protruding defect generated because a crystal plane having a different plane orientation from the substrate is generated. Once a hillock defect occurs, it is not flattened by the crystal grown thereon, and the crystal grows while maintaining the protruding shape. The present inventors have found that hillock defects occur at an early stage of growing a layer having a higher p-type impurity concentration than that of the base, and that the higher the p-type impurity concentration of the grown layer, the more hillock defects occur.
[0014]
Hillock defects occur because when the impurity material is rapidly increased in order to increase the impurity concentration, the movement of Ga and P, which are the main constituent elements of GaP, is temporarily hindered by the impurity material, and It is considered that the cause is that it cannot be uniformly dispersed over the entire crystal surface. In particular, group V elements such as P, As, N, and Sb are difficult to move and move in combination with group III elements. Therefore, the type of group III element used at the same time has a large relationship with the presence or absence of crystal defects. For example, when the group III element is Ga, the bonding with the group V element is weak, so that the group V element is likely to come off. As a result, it is considered that the group V element is not uniformly dispersed in the initial stage of the growth of the layer having a higher impurity concentration than the base, and hillocks are generated.
[0015]
The present invention suppresses generation of crystal defects such as hillocks by uniformly dispersing the group III element and the group V element, which are main constituent elements of the group III-V compound semiconductor crystal, over the entire crystal surface during the crystal growth process. It is another object of the present invention to provide a semiconductor light emitting device wafer in which the surface of an electrode is reduced and flattened to reduce the possibility of peeling of electrodes in the semiconductor light emitting device manufacturing process.
[0016]
[Means for Solving the Problems]
The semiconductor light-emitting device according to claim 1 of the present invention includes a substrate, a first clad layer made of at least a group III-V compound semiconductor crystal, a light-emitting layer, a second clad layer having a conductivity type opposite to that of the first clad layer, and A window electrode, and a lower electrode is formed on the substrate, and an upper electrode is formed on the window layer.DepartsA first window layer closer to the light layer and a second window layer farther from the light emitting layer;From BecomeThe second window layer is a semiconductor layer having a higher impurity concentration than the first window layer, and has an interface between the first window layer and the second window layer, and a portion near the interface of the first window layer.Is,The portion of the first window layer adjacent to the portion is more In ( High composition ratio of indium) element,Portion of the second window layer near the interfaceIs beforeNote2 window layersAdjacent to the part inpartMore InThe composition ratio of the elementshigh,The first and second window layers are made of In. _w Ga _x4 Al _1-w-x4 P (where 0 ≦ w ≦ 1, 0 ≦ x4 ≦ 1)It is characterized by the following.
[0017]
Further, each layer of the semiconductor of the semiconductor light emitting device according to the second aspect has the following configuration.
[0018]
Semiconductor substrate: GaAs,
First cladding layer: In_0.5(Ga_x1Al_1-x1)_0.5P (however, 0 ≦ x1 ≦ 1),
Active layer: In_0.5(Ga_x2Al_1-x2)_0.5P (however, 0 ≦ x2 <1) or Ga_yAl_1-yAs (however, 0 ≦ y ≦ 1) or In_zGa_1-zAs (where 0 ≦ z <1),
Second cladding layer: In_0.5(Ga_x3Al_1-x3)_0.5P (however, 0 ≦ x3 ≦ 1).
[0019]
[0020]
Claims3The semiconductor light emitting device according to the above,There is an interface between the second cladding layer and the first window layer,Of the first window layerThe portion near the interface is closer to the portion than the portion in the first window layer.Composition ratio of In elementButHighIIt is characterized by the following.
[0021]
Claims4In the semiconductor light-emitting device described in the above, a substrate, a first clad layer made of at least a group III-V compound semiconductor crystal, a light-emitting layer, a second clad layer of the opposite conductivity type to the first clad layer, and a window layer are arranged in this order. Electrodes are formed on one side of the substrate and the window layer, respectively.DepartsA first window layer closer to the light layer and a second window layer farther from the light emitting layer;Consists ofThe second window layer is a semiconductor layer having a higher impurity concentration than the first window layer, and near the interface between the first window layer and the second window layer;As you move away from the light emitting layerGradually increasing the impurity concentration in the second window layerThe In composition ratio in the second window layer near the interface between the first window layer and the second window layer is gradually increased substantially in proportion to the increase in impurity concentration.It is characterized by having.
[0022]
Claims5In the semiconductor light emitting device described above, the impurity concentration in the first window layer near the interface between the second cladding layer and the first window layer is gradually increased.
[0023]
[0024]
Claims6In the semiconductor light emitting device described above, a current blocking layer is provided on an interface between the second cladding layer and the first window layer, and the shape of the current blocking layer is substantially similar to the shape of the upper electrode. It is characterized by the following.
[0025]
Claims7In the semiconductor light emitting device described above, the current blocking layer has the following configuration.
Current blocking layer: In_vAl_x6Ga_1-v-x6P (however, 0 ≦ v ≦ 1, 0 ≦ x6 ≦ 1).
[0026]
Claims8The described semiconductor light emitting device is characterized in that the current blocking layer is provided at a central portion or a peripheral portion of the semiconductor light emitting device.
[0027]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[Embodiment 1]
1A and 1B are diagrams illustrating a semiconductor light emitting device according to a first embodiment of the present invention. FIG. 1A is a schematic cross-sectional view of the semiconductor light emitting device, and FIG. FIG. 4 is a diagram showing a distribution of an In composition ratio in a vertical direction.
[0028]
The crystal growth of the semiconductor light emitting device 100 according to the first embodiment of the present invention is performed using a reduced pressure MOVPE method (a reduced pressure MOCVD method), and each layer of the semiconductor light emitting device 100 has the following configuration. 1 is an n-type GaAs substrate, 2 is an n-type In_0.5Al_0.5P cladding layer, the impurity is Si and the impurity concentration is 5 × 10¹⁷cm^-3, The thickness is about 1 μm, and 3 is undoped In._0.5(Ga_0.55Al_0.45)_0.5P light emitting layer, thickness about 0.5 μm, 4 is p-type In_0.5Al_0.5P clad layer, impurity is Zn and impurity concentration is 5 × 10¹⁷cm^-3The thickness is about 1 μm, 11 is a p-type GaP first window layer, the impurity is Zn and the impurity concentration is 1 × 10¹⁸cm^-3A thickness of about 1 μm, 12 is a p-type GaP second window layer, the impurity is Zn and the impurity concentration is 1 × 10¹⁹cm^-3The first window layer 11 and the second window layer 12 form the window layer 5.
[0029]
After laminating the above layers, an n-side electrode 7 is formed on one side of the n-type GaAs substrate 1 and a p-side electrode 6 is formed on one side of the electrode forming surface 5a of the p-type window layer 12, and a semiconductor light emitting device wafer (hereinafter, referred to as “ "The wafer of the first embodiment"). The n-side electrode 7 is formed on the entire surface of the substrate 1, while the p-side electrode 6 has, for example, a circular shape with a diameter of about 100 μm in order to extract light. This wafer was divided into a size of about 300 μm square to produce a semiconductor light emitting device 100.
[0030]
The impurity concentration of Zn in the p-type GaP first window layer 11 and the p-type GaP second window layer 12 is 1 × 10¹⁸cm^-3And 1 × 10¹⁹cm^-3It has been found that a large drop in the impurity concentration distribution at the interface causes a rise in the hillock defect density of the second window layer 12, and as shown in FIG. Near the interface between the GaP first window layer 11 and the p-type GaP second window layer 12Is, Group III element InButAdditionIs, InGaPFromHas become.
[0031]
In the first embodiment, near the interface between the first window layer 11 and the p-type GaP second window layer 12, the thickness of about 0.1 μm_0.01Ga_0.99P layer (Zn impurity concentration 1 × 10¹⁸cm^-3) And about 0.1 μm thick In_0.01Ga_0.99P layer (Zn impurity concentration 1 × 10¹⁹cm^-3)WhenIt has a structure with.
[0032]
This is because In moves easily on the crystal surface like Ga, and the bond between In and the group V element is stronger than the bond between Ga and the group V element. Since the bond with the group V element (for example, P, As, N, Sb, etc.) is hard to be dissociated, the impurity Zn is uniformly dispersed on the crystal surface by the movement of the group V element by bonding with In. It is thought that it is possible.
[0033]
The ratio of the specific Group III element to the entire Group III element in the crystal is referred to as the composition ratio of the Group III element, and the thickness in the first window layer 11 and the second window layer 12 near the interface between the window layers 11 and 12 is defined. When the In composition ratio in the region having a thickness of 0.1 μm was set to about 0.01, uniform dispersion of the group V element could be realized.
[0034]
In summary, in the semiconductor light emitting device of the first embodiment, each layer of the semiconductor has the following configuration.
Semiconductor substrate: GaAs,
First cladding layer: In_0.5(Ga_x1Al_1-x1)_0.5P (however, 0 ≦ x1 ≦ 1),
Active layer: In_0.5(Ga_x2Al_1-x2)_0.5P (however, 0 ≦ x2 <1) or Ga_yAl_1-yAs (however, 0 ≦ y ≦ 1) or In_zGa_1-zAs (where 0 ≦ z <1),
Second cladding layer: In_0.5(Ga_x3Al_1-x3)_0.5P (however, 0 ≦ x3 ≦ 1),
Window layer: In_w Ga _x4 Al _1-w-x4P (however, 0 ≦ w ≦ 1, 0 ≦ x4 ≦ 1).
[0035]
FIG. 2 shows the hillock defect density on the vertical axis and the In composition ratio on the horizontal axis.of Near the interface1 shows an example of the measurement results of the hillock defect density with respect to the In composition ratio of the sample.
[0036]
In FIG. 2, the In composition ratio is approximately 5 × 10^-Four, 9 × 10^-Four, 4 × 10^-3, 4 × 10^-2And the hillock defect densities are about 1000, 100, 10, and 5 (number / cm, respectively).^Two) And that the hillock defect density is greatly reduced only by slightly increasing the In composition ratio from 0. FIG. 2 shows a measurement of a GaP single layer. In the case of a semiconductor light emitting device wafer, the decrease in the hillock defect density when the In composition ratio was increased was more moderate. When the In composition ratio is further increased, the hillock defect density also decreases, but does not decrease as sharply as when a small amount is added.
[0037]
On the other hand, when the In composition ratio of the window layer 5 is increased, the semiconductor is an indirect transition semiconductor up to the In composition ratio of 0.23, which is almost the same as the band gap value of the GaP semiconductor. As a result, current diffusion increases, and luminance improves. However, when the In composition ratio of the window layer 5 is further increased, the transmittance of the window layer 5 for green light is reduced, and the luminance of the semiconductor light emitting device is reduced. This is because the band gap of the window layer 5 becomes small.
[0038]
In a wafer for fabricating a semiconductor light emitting device of a conventional example (hereinafter, referred to as a “wafer of a conventional example”), a defect density is about 1000 defects / cm.^TwoHowever, in the wafer of the first embodiment, about 100 wafers / cm^TwoAnd decreased to 1/5. The yield when semiconductor light emitting devices are manufactured using the wafer of Embodiment 1 is improved by about 30% as compared with the case where a conventional wafer is used. The emission wavelength was green at 560 nm, and the luminance was able to be increased by about 20% as compared with the conventional semiconductor light emitting device.
[0039]
[Embodiment 2]
3A and 3B are diagrams illustrating a semiconductor light emitting device according to a second embodiment of the present invention. FIG. 3A is a schematic cross-sectional view of the semiconductor light emitting device, and FIG. FIG. 4 is a diagram showing a distribution of an In composition ratio in a vertical direction.
[0040]
The crystal growth of the semiconductor light emitting device 200 according to the second embodiment of the present invention is performed by using the low-pressure MOVPE method (low-pressure MOCVD method) as in the first embodiment.
[0041]
In the semiconductor light emitting device 200 according to the second embodiment, the entirety of the window layer 5 is In._0.01Ga_0.99P and p-type In_0.01Ga_0.99P first window layer (impurity is Zn and impurity concentration is 1 × 10¹⁸cm^-3, Thickness of about 1 μm) 21, p-type In_0.01Ga_0.99P second window layer (impurity is Zn and impurity concentration is 1 × 10¹⁹cm^-3, A thickness of about 5 μm) 22 to form the window layer 5.
[0042]
Then, near the interface between the first window layer 21 and the p-type GaP second window layer 22, a thickness of about 0.1 μm_0.05Ga_0.95P layer (Zn impurity concentration 1 × 10¹⁸cm^-3) And about 0.1 μm thick In_0.05Ga_0.95P layer (Zn impurity concentration 1 × 10¹⁹cm^-3)WhenThe other layers are the same as those of the semiconductor light emitting device of the first embodiment. Thus, it can be seen that the defect density is reduced even when the entire window layer 5 is made of InGaP.
[0043]
In the wafer having the semiconductor light emitting device configuration of the second embodiment (hereinafter, referred to as “wafer of the second embodiment”), the defect density is about 10 / cm.^TwoAnd 1/100 of that of the conventional wafer. The yield when a semiconductor light emitting device is manufactured using the wafer of the second embodiment is improved by about 40% as compared with the case where the semiconductor light emitting device is manufactured using the conventional wafer, and the luminance is about 20% higher than that of the conventional semiconductor light emitting device. % Increased.
[0044]
[Embodiment 3]
4A and 4B are diagrams illustrating a semiconductor light emitting device according to a third embodiment of the present invention. FIG. 4A is a schematic cross-sectional view of the semiconductor light emitting device, and FIG. FIG. 4 is a diagram showing a distribution of an In composition ratio in a vertical direction.
[0045]
In the semiconductor light emitting device 300 of the third embodiment, the entirety of the window layer 5 is In._0.01(Ga_0.8Al_0.2)_0.99It is the same as the semiconductor light emitting device of the second embodiment except that a P layer and a compound semiconductor layer containing Al are used.
[0046]
That is, p-type In_0.01Al_0.2Ga_0.79P first window layer (impurity is Zn and impurity concentration is 1 × 10¹⁸cm^-3, Thickness about 1 μm) 31, p-type In_0.01Al_0.2Ga_0.79P second window layer (impurity is Zn and impurity concentration is 1 × 10¹⁹cm^-3, A thickness of about 5 μm) 32 to form the window layer 5.
[0047]
Then, near the interface between the first window layer 31 and the p-type GaP second window layer 32, an In layer having a thickness of about 0.1 μm is formed._0.01Al_0.2Ga_0.79P layer (Zn impurity concentration 1 × 10¹⁸cm^-3) And about 0.1 μm thick In_0.01Al_0.2Ga_0.79P layer (Zn impurity concentration 1 × 10¹⁹cm^-3)WhenIt has a structure with. Thus, it can be seen that the defect density is reduced even when the entire window layer 5 is made of InAlGaP. By adding Al to the group III element constituting the window layer 5, the band gap of the window layer 5 can be prevented from being reduced.
[0048]
Although the group III element Al has an effect of widening the band gap of the window layer, it has a weak bonding force with a group V element (for example, P, As, N, Sb, etc.) like Ga, so that the effect of reducing crystal defects is low. There is no. Further, since the speed of moving the crystal surface is low, the effect of suppressing crystal defects due to In tends to be lost. For this reason, in a semiconductor light emitting device that emits green light, the In composition ratio in the first window layer 31 and the second window layer 32 near the interface between the first window layer 31 and the second window layer 32 is set to 0.2. It was difficult to do so.
[0049]
The defect density of the wafer having the semiconductor light emitting element configuration of the third embodiment (hereinafter, referred to as “wafer of the third embodiment”) is 30 defects / cm.^TwoAnd the defect density was about three times that of the wafer of the second embodiment. However, the defect density is about 1/30 as compared with the conventional wafer. The brightness of the semiconductor light emitting device of the third embodiment is the same as that of the conventional semiconductor light emitting device.ToIn comparison, it increased by about 30%.
[0050]
In summary, in the semiconductor light emitting device of the third embodiment, each layer of the semiconductor has the following configuration.
Semiconductor substrate: GaAs,
First cladding layer: In_0.5(Ga_x1Al_1-x1)_0.5P (however, 0 ≦ x1 ≦ 1),
Active layer: In_0.5(Ga_x2Al_1-x2)_0.5P (however, 0 ≦ x2 <1) or Ga_yAl_1-yAs (however, 0 ≦ y ≦ 1) or In_zGa_1-zAs (where 0 ≦ z <1),
Second cladding layer: In_0.5(Ga_x3Al_1-x3)_0.5P (however, 0 ≦ x3 ≦ 1),
Window layer: In_w Ga _x4 Al _1-x4P (however, 0 ≦ w ≦ 1, 0 ≦ x4 ≦ 1).
[0051]
[Embodiment 4]
5A and 5B are diagrams illustrating a semiconductor light emitting device according to a fourth embodiment of the present invention. FIG. 5A is a schematic cross-sectional view of the semiconductor light emitting device, and FIG. FIG. 4 is a diagram showing a distribution of an In composition ratio in a vertical direction.
[0052]
The crystal growth of the semiconductor light emitting device 400 according to the fourth embodiment of the present invention is performed by using a reduced pressure MOVPE method (a reduced pressure MOCVD method), and the second cladding layer 4 and the first window layer 41 are formed as shown in FIG. Is also added in the first window layer 41 near the interface with_0.01Ga_0.99P layerPointExcept for this, it is the same as the semiconductor light emitting device 100 of the first embodiment. The first window layer 41 and the second window layer 12 constitute the window layer 5.
[0053]
The wafer having the semiconductor light emitting device configuration of the fourth embodiment (hereinafter referred to as “wafer of the fourth embodiment”) has a defect density of about 80 defects / cm.^TwoThus, the yield in the case where a semiconductor light emitting device is manufactured using the wafer of the fourth embodiment is improved by about 40% as compared with the case where a conventional wafer is used.
[0054]
[Embodiment 5]
6A and 6B are diagrams illustrating a semiconductor light emitting device according to a fifth embodiment of the present invention. FIG. 6A is a schematic cross-sectional view of the semiconductor light emitting device, and FIG. FIG. 5 is a diagram showing a distribution of a p-type impurity concentration in a vertical direction.
[0055]
The semiconductor light emitting device 500 according to the fifth embodiment has a p-type (Zn) impurity concentration of 1 × in a 1 μm thick region in the second window layer 52 near the interface between the first window layer 11 and the second window layer 52. 10¹⁸cm^-3From 1 × 10¹⁹cm^-3It is the same as the semiconductor light emitting device of the first embodiment except that it is gradually increased by one digit.
[0056]
In the wafer having the semiconductor light emitting element configuration of the fifth embodiment (hereinafter, referred to as “wafer of the fifth embodiment”), the defect density of a conventional wafer is about 1000 / cm.^TwoWas about 500 pieces / cm^TwoAnd could be halved. The yield in the case where a semiconductor light emitting device is manufactured using the wafer of the fifth embodiment is improved by about 7% as compared with the case where a conventional wafer is used.
[0057]
Embodiment 6
7A and 7B are diagrams illustrating a semiconductor light emitting device according to a sixth embodiment of the present invention. FIG. 7A is a schematic cross-sectional view of the semiconductor light emitting device, and FIG. FIG. 9 is a diagram showing a distribution of an In composition ratio in a vertical direction and a distribution of a p-type impurity concentration of a first window layer 61 and a second window layer 62.
[0058]
The semiconductor light emitting device 600 of the sixth embodiment has a p-type impurity concentration of 5 μm in a 0.2 μm thick region in the first window layer 61 near the interface between the first window layer 61 and the second cladding layer 4. × 10¹⁷cm^-3From 1 × 10¹⁸cm^-3It is the same as the semiconductor light emitting device of the fifth embodiment except that it is gradually increased up to half a digit.
[0059]
The defect density of the wafer of the fifth embodiment is about 500 defects / cm.^TwoHowever, the defect density of the wafer having the semiconductor light emitting device configuration of the sixth embodiment (hereinafter referred to as “wafer of the sixth embodiment”) is about 300 defects / cm.^TwoAnd could be further reduced. The yield in the case where a semiconductor light emitting device was manufactured using the wafer of the sixth embodiment was improved by about 10% as compared with the yield in the case where a conventional wafer was used.
[0060]
Embodiment 7
8A and 8B are diagrams illustrating a semiconductor light emitting device according to a seventh embodiment of the present invention. FIG. 8A is a schematic cross-sectional view of the semiconductor light emitting device, and FIG. FIG. 8C is a diagram showing the distribution of the In composition ratio in the vertical direction, and FIG. 8C is a diagram showing the distribution of the p-type impurity concentration of the first window layer 61, the second window layer 62, and the second cladding layer.
[0061]
In the semiconductor light emitting device 700 according to the seventh embodiment, the composition of the first window layer 71 is In._0.01Ga_0.99In the P layer, the In composition ratio is gradually increased from 0.01 to 0.05 in a region having a thickness of about 1 μm in the first window layer 71 near the interface between the first window layer 71 and the second window layer 72. Let In_0.05Ga_0.95A p-type impurity concentration of 1 × 10¹⁸cm^-3From 1 × 10¹⁹cm^-3It is the same as the semiconductor light emitting device of the first embodiment except that it is gradually increased almost in proportion to the increase of the In composition ratio up to.
[0062]
In the wafer having the semiconductor light emitting device configuration of the seventh embodiment (hereinafter referred to as “wafer of the seventh embodiment”), the defect density is about 0 to 5 defects / cm.^TwoAnd almost no defect. The yield when semiconductor light emitting devices are manufactured using the wafer of the seventh embodiment is improved by about 50% as compared with the case where a conventional wafer is used.
[0063]
Embodiment 8
FIG. 9 is a schematic cross-sectional view illustrating a semiconductor light emitting device 800 according to Embodiment 8 of the present invention. The difference from the semiconductor light emitting device 100 of the first embodiment is that n is provided on the second cladding layer 4 between the second cladding layer 4 and the first window layer 11 and at a position facing the p-side electrode 6. This is the point that the mold current blocking layer 8 is provided.
[0064]
Light generated in the portion of the light emitting layer 3 located below the p-side electrode 6 is reflected by the p-side electrode 6 and is hardly radiated to the outside. That is, the light emitting current flowing through the region of the light emitting layer 3 located below the p-side electrode 6 is a reactive current that does not significantly contribute to the external light emitting output. The n-type current blocking layer 8 forms an n-p junction at the interface with the p-type second cladding layer 4. When a forward bias voltage is applied to both electrodes 6 and 7 in order to cause a current to flow through the semiconductor light emitting element, the junction becomes reverse biased and blocks the flow of current. Therefore, all the current injected into the semiconductor light emitting element flows to a portion of the light emitting layer 3 that is not opposed to the p-side electrode 6, and almost no reactive current is generated. In this case, the shape of the current blocking layer 8 is substantially similar to the shape of the upper p-type electrode 6.
[0065]
The composition of the n-type current blocking layer 8 is generally In_vAl_x6Ga_1-v-x6P (however, 0 ≦ v ≦ 1, 0 ≦ x6 ≦ 1) is used, and as an example of a desirable composition, In_0.01Al_0.01Ga_0.98There is P.
[0066]
In the semiconductor light emitting device according to the eighth embodiment, the p-side electrode 6 and the n-type current blocking layer 8 have a circular shape with a diameter of about 100 μm. This is because the area of the p-side electrode 6 is set to the minimum necessary size capable of bonding a wire to be applied for flowing a current, and the reduction in luminance due to the p-side electrode 6 is minimized. The p-side electrode 6 and the n-type current blocking layer 8 are provided at the center of the device. Therefore, a current can be uniformly applied to the entire surface of the light emitting layer 3, and the luminance of the semiconductor light emitting device can be increased by about 40% as compared with the conventional example. This semiconductor light emitting device can be used for applications such as outdoor display panels.
[0067]
Embodiment 9
FIG. 10 is a schematic sectional view of a semiconductor light emitting device 900 according to the ninth embodiment of the present invention. Similarly to the semiconductor light emitting device 800 of the eighth embodiment, an n-type current blocking layer 8 is provided between the second cladding layer 4 and the first window layer at a position facing the p-side electrode 6 on the second cladding layer 4. . In the semiconductor light emitting device 900 according to the ninth embodiment, the p-side electrode 6 and the n-type current blocking layer 8 are provided in the peripheral portion of the device except for a circular portion having a diameter of about 100 μm in the central portion of the device. Since the current is concentrated in a narrow portion having a diameter of about 100 μm at the center of the element, the response speed of ON / OFF of light with respect to ON / OFF of the current can be increased, and therefore, it can be used as a light source for optical communication.
[0068]
The area S of the portion where the p-side electrode 6 and the n-type current blocking layer 8 are not formed is determined by the required brightness and the value of the response speed. In other words, when the response speed may be slow but high luminance is required, S is increased. Conversely, when the luminance may be low but the response speed needs to be increased, S is decreased.
[0069]
Regarding the relationship between the area S and the luminance B, even if the area S is increased, the luminance B does not change much. This is because, when the area S is increased, the current density decreases, and the luminance B is proportional to the current amount.
[0070]
On the other hand, regarding the relationship between the area S and the response speed τ, when the area S is reduced, the response speed τ is improved. However, if it is too small, the adverse effect of increasing the resistance occurs. As an example, when the area S = 100 μmφ, the current I = 20 mA and the forward voltage V_F= 1.95 V, S = 50 μmφ, I = 20 mA, and forward voltage V_F= 2.2 V, and the response speed τ is improved by about 20%. However, the forward voltage V_FIncreases by 0.25 V, and therefore, in the present invention, the area S = 100 μmφ is often used. As an example of a specific numerical value of the response speed τ, by setting the area S = 100 μmφ, the response speed τ17.1 μs could be improved to 4.4 μs.
[0071]
The light emitting layer is In_0.1Ga_0.9By using As, a semiconductor light emitting element having an emission wavelength of 950 nm can be obtained, which is effective as a light source for wireless communication using infrared light. On the other hand, the light-emitting layer is Ga_0.9Al_0.1By using As, a semiconductor light emitting device having an emission wavelength of 850 nm can be obtained. By using two semiconductor light emitting elements having different emission wavelengths as light sources, wavelength multiplex wireless communication using infrared light can be performed. Further, by changing the emission wavelength between the upstream signal and the downstream signal, full-duplex wireless communication using infrared light can be performed.
[0072]
Further, since the light emitting area is small, it is easy to make the light emitted from the semiconductor light emitting element enter the optical fiber. In particular, when a plastic optical fiber (APF) having a core is used as the optical fiber, the light emitting layer 3 is made of In._0.5(Ga_xAl_1-x)_0.5By setting P and adjusting the composition ratio x of Al between 0 and 1, a semiconductor light emitting device having an emission wavelength of 550 nm to 680 nm with a small APF transmission loss can be obtained. This semiconductor light emitting device is effective as a light source for optical fiber communication using an APF.
[0073]
In the above description, the case where the crystal thin film lattice-matched to the substrate is used for the first cladding layer, the light-emitting layer, and the second cladding layer, but it is clear that the effect is not changed even if the lattice mismatch crystal thin film is used. is there.
[0074]
Also, although the case of GaAs has been described as the substrate, insulating substrates such as sapphire, group IV semiconductors such as Si (silicon) and SiC (silicon carbide), and group II-VI compound semiconductors such as ZnSe may be used. good.
[0075]
Further, the case where P is used as the group V element has been described, but the same effect can be obtained by using other group V elements such as As, N, and Sb.
[0076]
In summary, when a plurality of window layers having different impurity concentrations are stacked, the main constituent elements constituting the window layers move rapidly on the crystal surface during the crystal growth process as a group III element, and have a strong bond with the group V element. It is important to add In. However, since In reduces the band gap of the semiconductor, the amount of addition needs to be in a range that keeps the transmittance of light generated in the light emitting layer high.
[0077]
【The invention's effect】
According to the semiconductor light emitting device of claim 1 of the present invention, a substrate, a first cladding layer made of at least a group III-V compound semiconductor crystal, a light emitting layer, and a second cladding layer of a conductivity type opposite to the first cladding layer. , And a window layer are laminated in this order, a lower electrode is formed on the substrate, and an upper electrode is formed on the window layer.DepartsA first window layer closer to the light layer and a second window layer farther from the light emitting layer;Consists ofThe second window layer is a semiconductor layer having a higher impurity concentration than the first window layer, and has an interface between the first window layer and the second window layer, and a portion near the interface of the first window layer.Is,In the first window layer From the part adjacent to the part ( High composition ratio of indium) element,Portion of the second window layer near the interfaceIs beforeNote2 window layersAdjacent to the part inpartMore InThe composition ratio of the elementshigh,The first and second window layers are made of In. _w Ga _x4 Al _1-w-x4 P (where 0 ≦ w ≦ 1, 0 ≦ x4 ≦ 1)It is characterized by the following.
[0078]
Therefore, crystal defects (crystal defects called hillocks) on the electrode forming surface of the window layer of the wafer having the semiconductor light emitting element configuration can be greatly reduced, and as a result, semiconductor light emission using this wafer can be achieved. It is possible to reduce the occurrence of defective products due to electrode peeling during device fabrication, and to increase the production yield of semiconductor light emitting devices.
[0079]
According to the semiconductor light emitting device of the second aspect, each layer of the semiconductor has the following configuration.
Semiconductor substrate: GaAs,
First cladding layer: In_0.5(Ga_x1Al_1-x1)_0.5P (however, 0 ≦ x1 ≦ 1),
Active layer: In_0.5(Ga_x2Al_1-x2)_0.5P (however, 0 ≦ x2 <1) or Ga_yAl_1-yAs (however, 0 ≦ y ≦ 1) or In_zGa_1-zAs (where 0 ≦ z <1),
Second cladding layer: In_0.5(Ga_x3Al_1-x3)_0.5P (however, 0 ≦ x3 ≦ 1).
[0080]
Therefore, compared to the conventional GaP, by adding In or Al, it is possible to provide a wafer configuration capable of reducing crystal defects on the electrode forming surface of the window layer of the wafer having the semiconductor light emitting element configuration.
[0081]
Claims1Semiconductor light emitting device as describedToAccording to, HalfIt is possible to provide a wafer manufacturing means capable of reducing crystal defects on an electrode forming surface of a window layer of a wafer having a conductive light emitting element configuration. If In is excessively added to the window layer, the resistivity increases as compared with the conventional GaP, and the operating voltage (forward voltage V_F) Increases, but by increasing the composition ratio of the In element only in the second window layer, crystal defects are reduced and the composition ratio of the In element in the first window layer is low, so that the operating voltage is lowered. be able to.
[0082]
Furthermore, from claim 12Wherein the substrate, a first cladding layer made of a III-V compound semiconductor crystal, a light emitting layer, a second cladding layer of the opposite conductivity type, and a window layer are crystal-grown in this order, An electrode is formed on each of the substrate and the window layer. The window layer has at least a first window layer near the light emitting layer and a second window layer far from the light emitting layer, and the second window layer is the first window layer. A semiconductor light emitting device having a higher impurity concentration, wherein a composition ratio of a main constituent element of the group III-V compound semiconductor crystal in the first window layer and the second window layer or an impurity concentration in the second window layer is By changing the density near the interface between the first window layer and the second window layer to uniformly disperse the main constituent elements in the crystal growth process, crystal defects on the electrode forming surface of the window layer can be reduced. In particular, as a means for uniformly dispersing the main constituent elements in the crystal growth process, the In composition ratio in the first window layer and the second window layer in the vicinity of the interface between the first window layer and the second window layer is determined by the interface. It is characterized in that it is higher than the In composition ratio in each layer away from the vicinity.
[0083]
Claims3According to the semiconductor light emitting device according to the above,There is an interface between the second cladding layer and the first window layer,Of the first window layerThe portion near the interface is closer to the portion than the portion in the first window layer.Composition ratio of In elementButHighIIt is characterized by the following.
[0084]
Therefore, a crystal defect on the electrode forming surface of the window layer of the wafer having the semiconductor light emitting device configuration is claimed.1With respect to the above means, it is possible to provide a wafer manufacturing means that can be further reduced. Further, since there are many crystal defects near the interface between the second cladding layer and the first window layer (about 0.1 μm thick), the operating voltage is significantly increased by increasing the In composition ratio only near this interface. And crystal defects can be reduced.
[0085]
Claims3The semiconductor light emitting device according to the invention described in (1), as means for uniformly dispersing the main constituent elements in the crystal growth process, in addition to the vicinity of the interface between the first window layer and the second window layer, the light emitting layer and the first The In composition ratio in the first window layer near the interface of the window layer is higher than the In composition ratio in the first window layer far from the vicinity of the interface.
[0086]
Claims4According to the described semiconductor light emitting device, the substrate, the first cladding layer made of at least a group III-V compound semiconductor crystal, the light emitting layer, the second cladding layer of the opposite conductivity type to the first cladding layer, and the window layer are provided. Electrodes are formed on one side of the substrate and the window layer, respectively.DepartsA first window layer closer to the light layer and a second window layer farther from the light emitting layer;Consists ofThe second window layer is a semiconductor layer having a higher impurity concentration than the first window layer, and near the interface between the first window layer and the second window layer;As you move away from the light emitting layerGradually increasing the impurity concentration in the second window layerThe In composition ratio in the second window layer near the interface between the first window layer and the second window layer is gradually increased substantially in proportion to the increase in impurity concentration.It is characterized by having.
[0087]
Therefore, it is possible to provide a wafer manufacturing means for reducing crystal defects on the electrode forming surface of the window layer without reducing the transmittance of the window layer of the wafer having the semiconductor light emitting element structure with respect to the emission wavelength. In the conventional example, crystal defects were easily generated in the vicinity of the interface where the impurity concentration was sharply changed.However, by gradually increasing the impurity concentration, the transmittance and the resistivity were not different from those of the conventional example, so the operating voltage was also low. The effect was slightly smaller than that in the case where In was added, but the crystal defects could be reduced to about 1/2 and the yield could be improved by about 7%.
[0088]
Claims5According to the above described semiconductor light emitting device, the impurity concentration in the first window layer near the interface between the second cladding layer and the first window layer is gradually increased.
[0089]
Therefore, crystal defects on the electrode forming surface of the window layer can be determined without reducing the transmittance of the window layer of the wafer having the semiconductor light emitting element configuration with respect to the emission wavelength.4It is possible to provide a wafer manufacturing means for further reducing the number of wafers as compared with the means. In the vicinity of the interface between the cladding layer and the window layer, crystal defects are likely to occur, but the effect is slightly smaller than that in the case where In is increased by increasing the impurity concentration near the interface to increase the transmittance and the operating voltage. The crystal defects could be reduced to about 3/10.
[0090]
Further, in the semiconductor light emitting device according to claim 4, the In composition ratio in the second window layer near the interface between the first window layer and the second window layer is gradually increased almost in proportion to the increase in the impurity concentration.AndYou.
[0091]
Therefore, a crystal defect on the electrode forming surface of the window layer of the wafer having the semiconductor light emitting device configuration is claimed.3,5With respect to the means described above, a wafer manufacturing means that can be further reduced can be provided. As a result, the yield could be improved by about 50%.
[0092]
Claims6According to the semiconductor light emitting device described above, a current blocking layer is provided on the interface between the second cladding layer and the first window layer, and the shape of the current blocking layer is substantially similar to the shape of the upper electrode. It is characterized by being.
[0093]
Therefore, it is possible to provide a semiconductor light emitting device having few crystal defects on the electrode forming surface of the window layer of the wafer having the semiconductor light emitting device configuration, good yield, and low reactive current. As a result, the brightness of the semiconductor light emitting device could be increased by about 40%.
[0094]
Claims7Semiconductor light emitting device as describedToAccording to this, the current blocking layer has the following configuration.
Current blocking layer: In_vAl_x6Ga_1-v-x6P (however, 0 ≦ v ≦ 1, 0 ≦ x6 ≦ 1).
[0095]
Therefore, it is possible to provide a semiconductor light emitting device having few crystal defects on the electrode forming surface of the window layer of the wafer having the semiconductor light emitting device structure, good yield, and low reactive current. Since the InAlGaP current blocking layer containing In and Al is provided between the cladding layer and the window layer, crystal defects can be further reduced.^TwoIt could be reduced to the extent.
[0096]
Claims8Semiconductor light emitting device as describedToAccording to the present invention, the current blocking layer is provided at a central portion or a peripheral portion of the semiconductor light emitting device.
[0097]
Accordingly, a semiconductor light emitting device having few crystal defects on the electrode forming surface of the window layer, a high yield, and high luminance, or a semiconductor light emitting device having a fast response of light ON / OFF to current ON / OFF (fast modulation speed). Can be provided. Further, when the current blocking layer is provided in the peripheral portion of the semiconductor light emitting element, the current is concentrated in the central portion, and the current density of the light emitting portion increases, so that it is possible to select a small operating current. The response speed is determined by setting the area S = 100 μmφ, which makes it possible to obtain7The light emitting response speed τ of the semiconductor light emitting device described above is 17.1 μs.8The emission response speed τ of the described semiconductor light emitting device could be improved to 4.4 μs.
[Brief description of the drawings]
1A and 1B are diagrams illustrating a semiconductor light emitting device according to a first embodiment of the present invention, wherein FIG. 1A is a schematic cross-sectional view of the semiconductor light emitting device, and FIG. 1B is an In composition ratio in a thickness direction of a window layer. FIG.
FIG. 2 is a diagram illustrating the dependency of the hillock density on the In composition ratio in a GaP single layer on a GaAs substrate according to the present invention.
3A and 3B are diagrams illustrating a semiconductor light emitting device according to a second embodiment of the present invention, wherein FIG. 3A is a schematic sectional view of the semiconductor light emitting device, and FIG. 3B is an In composition ratio in a thickness direction of a window layer. FIG.
4A and 4B are diagrams illustrating a semiconductor light emitting device according to a third embodiment of the present invention, wherein FIG. 4A is a schematic cross-sectional view of the semiconductor light emitting device, and FIG. 4B is an In composition ratio in a thickness direction of a window layer. FIG.
5A and 5B are diagrams illustrating a semiconductor light emitting device according to a fourth embodiment of the present invention, wherein FIG. 5A is a schematic cross-sectional view of the semiconductor light emitting device, and FIG. 5B is an In composition ratio in the thickness direction of the window layer. FIG.
6A and 6B are diagrams illustrating a semiconductor light emitting device according to a fifth embodiment of the present invention. FIG. 6A is a schematic cross-sectional view of the semiconductor light emitting device, and FIG. 6B is a diagram illustrating a p-type impurity in a thickness direction of a window layer. It is a figure showing distribution of density.
7A and 7B are diagrams illustrating a semiconductor light emitting device according to a sixth embodiment of the present invention, in which FIG. 7A is a schematic cross-sectional view of the semiconductor light emitting device, and FIG. 7B is an In composition ratio in a thickness direction of a window layer. FIG. 6 is a diagram showing a distribution of the p-type impurity concentration of the first window layer 61 and the second window layer 62.
8A and 8B are diagrams illustrating a semiconductor light emitting device according to Embodiment 7 of the present invention, wherein FIG. 8A is a schematic cross-sectional view of the semiconductor light emitting device, and FIG. 8B is an In composition ratio in the thickness direction of the window layer. FIG. 4C is a diagram showing the distribution of the p-type impurity concentration in the first window layer, the second window layer, and the second cladding layer.
FIG. 9 is a schematic sectional view illustrating a semiconductor light emitting device according to an eighth embodiment of the present invention.
FIG. 10 is a schematic sectional view illustrating a semiconductor light emitting device according to a ninth embodiment of the present invention.
FIG. 11 is a schematic sectional view of a semiconductor light emitting device of Conventional Example 1.
FIG. 12 is a schematic sectional view of a semiconductor light emitting device of Conventional Example 2.
[Explanation of symbols]
100 Semiconductor light-emitting device according to Embodiment 1 of the present invention
200 Semiconductor Light Emitting Element of Second Embodiment of Present Invention
300 Semiconductor Light-Emitting Element of Third Embodiment of Present Invention
400 Semiconductor Light-Emitting Element of Fourth Embodiment of Present Invention
500 Semiconductor Light-Emitting Element of Embodiment 5 of the Present Invention
600 Semiconductor Light-Emitting Element of Sixth Embodiment of Present Invention
700 Semiconductor Light Emitting Element of Embodiment 7 of the Present Invention
800 Semiconductor light emitting device of embodiment 8 of the present invention
900 Semiconductor light emitting device according to embodiment 9 of present invention
1 n-type GaAs substrate
2 n-type In_0.5Al_0.5P clad layer
3 Undoped In_0.5(Ga_0.55Al_0.45)_0.5P light emitting layer
4 p-type In_0.5Al_0.5P clad layer
5 Window layer
5a Electrode formation surface
6 p-side electrode (upper electrode)
7 n-side electrode (lower electrode)
8 n-type current blocking layer
11 p-type GaP first window layer
12 p-type GaP second window layer
21 p-type In_0.01Ga_0.99P first window layer
22 p-type In_0.01Ga_0.99P second window layer
31 p-type In_0.01Al_0.2Ga_0.79P first window layer
32 p-type In_0.01Al_0.2Ga_0.79P second window layer
41 First window layer
61 1st window layer
62 Second window layer
71 p-type In_0.01Ga_0.99P first window layer
72 Second window layer

Claims (8)

A substrate, a first cladding layer made of at least a group III-V compound semiconductor crystal, a light-emitting layer, a second cladding layer having a conductivity type opposite to that of the first cladding layer, and a window layer are laminated in this order;
A lower electrode on the substrate, and an upper electrode on the window layer;
The window layer is composed of a first window layer closer to the light emission layer and the light emitting layer farther the second window layer, said second window layer is a semiconductor layer having high impurity concentration than the first window layer,
There is an interface between the first window layer and the second window layer,
A portion of the first window layer near the interface has a higher composition ratio of In ( indium) element than a portion of the first window layer adjacent to the portion ,
The vicinity of the interface portion of the second window layer has a high composition ratio of In element than the portion and the adjacent portion of the previous SL second window layer,
The first, the second window layer _{In w Ga x4 Al 1-w} -x4 P ( where, 0 ≦ w ≦ 1,0 ≦ x4 ≦ 1) semiconductor light emitting device characterized by comprising a. The semiconductor light emitting device according to claim 1,
Each of the semiconductor layers has the following configuration.
Semiconductor substrate: GaAs,
First cladding layer: In _0.5 (Ga _x1 Al _1-x1 ) _0.5 P (0 ≦ x1 ≦ 1),
Active _{layer: In 0.5 (Ga x2 Al 1} -x2) 0.5 P ( where, 0 ≦ x2 <1), _{or, Ga y Al 1-y As} ( where, 0 ≦ y ≦ 1), or, an In _z Ga _{1 -z} As (where 0 ≦ z <1),
Second cladding layer: In _0.5 (Ga _x3 Al _1-x3 ) _0.5 P (where 0 ≦ x3 ≦ 1 ). The semiconductor light emitting device according to claim 1,
There is an interface between the second cladding layer and the first window layer,
Wherein the vicinity of the interface portion of the first window layer, the semiconductor light emitting element according to the part and have a composition ratio of In element higher than adjacent portions This and wherein in the first window layer. A substrate, a first cladding layer made of at least a group III-V compound semiconductor crystal, a light-emitting layer, a second cladding layer having a conductivity type opposite to that of the first cladding layer, and a window layer are laminated in this order;
Electrodes are formed on one surface of the substrate and the window layer, respectively.
The window layer is composed of a first window layer closer to the light emission layer and farther from the light-emitting layer and the second window layer,
The second window layer is a semiconductor layer having a higher impurity concentration than the first window layer,
Near the interface between the first window layer and the second window layer, gradually increasing the impurity concentration in the second window layer as the distance from the light emitting layer increases ;
A semiconductor light emitting device wherein an In composition ratio in the second window layer near an interface between the first window layer and the second window layer is gradually increased almost in proportion to an increase in impurity concentration . The semiconductor light emitting device according to claim 4,
A semiconductor light emitting device wherein an impurity concentration in the first window layer near an interface between the second cladding layer and the first window layer is gradually increased. The semiconductor light emitting device according to claim 1,
A semiconductor light emitting device, wherein a current blocking layer is provided on an interface between the second cladding layer and the first window layer, and the shape of the current blocking layer is substantially similar to the shape of the upper electrode. element. The semiconductor light emitting device according to claim 6,
A semiconductor light emitting device, wherein the current blocking layer has the following configuration.
Current blocking layer: In _v Al _x6 Ga _1-v-x6 P (where 0 ≦ v ≦ 1, 0 ≦ x6 ≦ 1). The semiconductor light emitting device according to claim 6,
The semiconductor light emitting device, wherein the current blocking layer is provided at a central portion or a peripheral portion of the semiconductor light emitting device.

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