JP3780887B2 - Semiconductor light emitting device and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a semiconductor light emitting device and a method for manufacturing the same. This semiconductor light emitting element can be used as, for example, a light emitting diode or a laser diode.
[0002]
[Prior art]
As a light-emitting element in the visible light short wavelength region, one using a compound semiconductor is known. In particular, Group III nitride semiconductors are attracting particular attention recently because they are of direct transition type and have high luminous efficiency and emit blue light, which is one of the three primary colors of light.
[0003]
As one of such light emitting elements, there is one in which an AlN buffer layer, a first cladding layer, a light emitting layer, and a second cladding layer are sequentially stacked on a sapphire substrate. Here, the first and second clad layers are made of _{Al X In Y Ga 1-XY} N ( including X = 0, Y = 0, X = Y = 0). For example, the light emitting layer is formed by repeatedly laminating a barrier layer made of In _Y1 Ga _{1 -Y1} N (Y1 ≧ 0) and a quantum well layer made of In _Y2 Ga _{1 -Y2} N (Y2> Y1 and Y2> 0). It is a lattice structure.
These semiconductor layers are formed according to a conventional method by an organic metal compound vapor phase growth method (hereinafter referred to as “MOVPE method”).
[0004]
[Problems to be solved by the invention]
The light emitting layer having such a superlattice structure is formed at a relatively low growth temperature because steepness is required for the difference in composition between the barrier layer and the quantum well layer. In general, the barrier layers are formed to have the same thickness, and similarly, the quantum well layers are formed to have the same thickness. This is because if there is a difference in the thickness of each layer, the light generated from the quantum well layer may slightly change in terms of wavelength due to the quantum effect.
On the other hand, the second clad layer formed on the light emitting layer is formed at a temperature higher than that of the light emitting layer because of its thickness (thicker than the barrier layer and quantum well layer) and composition.
The present inventors have noticed the following problems when manufacturing a semiconductor light emitting device in this way.
[0005]
In the superlattice structure light-emitting layer, if the layer in contact with each cladding layer is a quantum well layer, the following problems occur. When the cladding layer is of p-conductivity type, if the quantum well layer is continuous, the energy order is different between the cladding layer and the barrier layer. Therefore, the so-called well depth of the quantum well layer is different from that of the other quantum well layers. It will be different. Therefore, the wavelength of light may shift. In addition, when the cladding layer is of the n-conduction type, if the quantum well layer is continuous therewith, the energy level of the cladding layer is lower than that of the quantum well layer, so that a so-called well is not formed in the quantum well layer. Can no longer be expected.
[0006]
[Means for Solving the Problems]
In order to solve such a problem, according to the first invention, a first semiconductor layer made of n-conducting GaN,
A barrier layer formed on the first semiconductor layer and made of In _Y1 Ga _{1 -Y1} N (Y1 ≧ 0) not doped with intentional impurities; In _Y2 Ga without intentional impurities doped A light-emitting layer having a superlattice structure formed by stacking quantum well layers made of _1-Y2 N (Y2> Y1 and Y2>0);
In the semiconductor light emitting device including the second semiconductor layer formed on the light emitting layer and made of p-conduction type AlGaN,
The layer in contact with each clad layer of the light emitting layer was determined as a barrier layer. That is, the configuration of the light emitting layer was a barrier layer-quantum well layer --- quantum well layer-barrier layer.
In this specification, the first semiconductor layer and the second semiconductor layer correspond to a clad layer or a light guide layer. Further, impurities caused by the background when growing semiconductor layers such as barrier layers and quantum well layers do not correspond to intentional impurities.
[0007]
However, as the inventors of the present application further studied, the following problems were further found.
In other words, when the second cladding layer is formed on the light emitting layer having a superlattice structure, a barrier layer (hereinafter referred to as “uppermost barrier layer”) that is the uppermost layer of the light emitting layer is thinned. This is presumably because the formation temperature of the second cladding layer is higher than the formation temperature of the uppermost barrier layer, so that the material of the uppermost barrier layer is blown from the upper surface when the second cladding layer is formed.
A thinner uppermost barrier layer is not preferable because the wavelength of light shifts to the short wavelength side due to the quantum effect.
Further, when the barrier layer is designed to be thin (for example, several nm in thickness), the uppermost barrier layer may be substantially absent.
[0008]
In order to solve such a problem, according to the second invention, the first semiconductor layer made of Al _X In _Y Ga _1-XY N (including X = 0, Y = 0, X = Y = 0) Forming a step;
A barrier layer made of In _Y1 Ga _{1 -Y1} N (Y1 ≧ 0) and a quantum well layer made of In _Y2 Ga _{1 -Y2} N (Y2> Y1 and Y2> 0) are stacked on the first semiconductor layer. And forming a superlattice structure light emitting layer,
Semiconductor comprising the steps of forming a second semiconductor layer made of _{Al A In B Ga 1-AB} N on the light emitting layer (including A = 0, B = 0, A = B = 0), the In the method for manufacturing a light emitting device,
The uppermost barrier layer that is the uppermost layer of the light emitting layer is formed thicker than the other barrier layers.
[0009]
According to a third invention, in the second invention, when forming the second semiconductor layer, the upper surface of the uppermost barrier layer is eliminated, and the thickness of the uppermost barrier layer is set to the thickness of another barrier layer. And substantially the same.
[0010]
A further object of the present invention is to provide a semiconductor light emitting device in which the peak wavelength of emitted light does not substantially change even when the applied current changes.
This object is achieved by the inventions described in claims 1-7.
[0011]
Another object of the present invention is to provide a semiconductor light emitting device that emits light having a narrow wavelength distribution, that is, close to ideal monochromatic light.
This object is achieved by the inventions described in claims 2 to 7.
[0012]
Another object of the present invention is to provide a semiconductor light emitting device having an active layer with a superlattice structure that has high luminous efficiency and exhibits strong light emission.
This object is achieved by the inventions according to claims 7-9.
[0013]
[Operation and effect of the invention]
According to the first invention, since the layer in contact with the first semiconductor layer and the second semiconductor layer in the light emitting layer serves as a barrier layer, the quantum well layer closest to each semiconductor layer also has a so-called quantum well shape, The potential depression is substantially the same as the other quantum well layers. Thus, the wavelengths of light emitted from each quantum well are substantially equal.
According to the first invention, the barrier layer made of In _Y1 Ga _{1 -Y1} N as the light emitting layer is grown on the first semiconductor layer made of n-conducting GaN. Since the composition ratio of In in the barrier layer is 0 or relatively small as compared with the quantum well layer, the composition is close to that of the first semiconductor layer made of GaN, and thus the crystal of the light emitting layer is hardly strained.
[0014]
According to the second invention, since the uppermost barrier layer is formed thicker than the other barrier layers, even when the material of the surface of the uppermost barrier layer disappears when forming the second semiconductor layer, It does not substantially disappear. For this purpose, of course, the thickness of the uppermost barrier layer is designed in anticipation of the thickness that disappears when the second semiconductor layer is formed.
[0015]
According to the third invention, after the second semiconductor layer is formed, the thickness that disappears during the formation of the second semiconductor layer is anticipated so that the thickness of the uppermost barrier layer is the same as the thickness of the other barrier layers. The thickness of the uppermost barrier layer is designed. Thereby, the thickness of each barrier layer becomes substantially the same in the light emitting layer having a superlattice structure, and wavelength shift due to the quantum effect can be prevented in advance.
[0016]
According to the first to seventh aspects of the present invention, the peak wavelength of light emitted from the semiconductor light emitting device does not substantially change even when the applied current changes.
[0017]
According to the second to seventh aspects of the invention, the wavelength distribution is narrowed in the light emitted from the semiconductor light emitting device. That is, light close to ideal monochromatic light is emitted from the semiconductor light emitting element.
[0018]
According to the seventh to ninth aspects of the present invention, the light emission efficiency in the light emitting layer having a superlattice structure is high and the light emission intensity is increased.
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in more detail based on examples.
[0019]
First Embodiment The semiconductor light emitting device of this embodiment is a blue light emitting diode. FIG. 1 shows a cross-sectional view of a light emitting diode 20 of the embodiment.
[0020]
A buffer layer 2 made of AlN having a thickness of 20 nm is formed on the surface a of a sapphire substrate 1 having a thickness of 100 μm. The buffer layer 2 can have a thickness of 20 to 50 nm, and the growth temperature of the film is 400.degree.
[0021]
On the buffer layer 2, an n-conductivity type semiconductor layer 3 is formed in two layers. The n layer 3 includes, from below, an n ⁺ -GaN layer 3a (carrier density: 2 ^× 10 ¹⁸ / cm ³ ) doped with 2.5 μm thick silicon and silicon having a thickness of 0.5 μm. Is doped with an n-GaN layer 3b (first cladding layer (first semiconductor layer), carrier density: 2 × 10 ¹⁷ / cm ³ ).
[0022]
The n layer 3 may be formed of _{Al X In Y Ga 1-XY} N consisting (X = 0, Y = 0 , X = Y = 0 and including) compound semiconductor. The n layer 3 can be composed of one layer.
[0023]
A light emitting layer 5 having a superlattice structure is formed on the n layer 3. The light emitting layer 5 is composed of a barrier layer 5a made of GaN not doped with an intentional impurity having a thickness of 3.5 nm and In _0.16 Ga _0.84 N not doped with an intentional impurity having a thickness of 3.5 nm. The quantum well layer 5b is repeatedly stacked. In this example, the number of repetitions was 5. The uppermost barrier layer 5c is made of GaN having a thickness of 3.5 nm and not doped with intentional impurities.
[0024]
In the above, the number of repetitions of the barrier layer 5a and the quantum well layer 5b is not particularly limited. The barrier layers 5a and 5c are compound semiconductors made of In _Y1 Ga _{1 -Y1} N (Y1 ≧ 0), and the quantum well layers 5b are compound semiconductors made of In _Y2 Ga _{1 -Y2} N (Y2> Y1 and Y2> 0). Can be formed. It is preferable to make the thickness of the uppermost barrier layer 5c substantially equal to the thickness of the other barrier layer 5a because the influence of the quantum effect is eliminated.
The barrier layers 5a and 5c and the quantum well layer 5b can be doped with impurities.
[0025]
According to the study by the present inventors, it was found that when the film thickness of the quantum well layer 5b is 3 to 5 nm, strong light emission can be obtained from the light emitting layer. The examination will be described below.
In the device of the example, the thickness of the quantum well layer is changed to 10 nm, 7 nm, 5 nm, and 3 nm, and the light emission intensity is measured. Note that the thickness of the barrier layer is also changed to be the same as the thickness of the quantum well layer. The emission intensity is the intensity of electroluminescence (unit: au). According to the study by the present inventors, when the film thickness of the quantum well layer is 7 nm, the light emission intensity is about 10 times the light emission intensity when the film thickness of the quantum well layer is 10 nm. When the thickness was 5 nm, the emission intensity was about 60 times, and when the film thickness was 3 nm, the emission intensity was about 150 times.
From the above results, it is understood that when the barrier layer is made of non-doped GaN and the quantum well layer is made of non-doped InGaN, the thickness of the quantum well layer is preferably 3 to 5 nm. The thickness of the barrier layer is preferably 3 nm or more.
[0026]
In this embodiment, the layer in contact with the first cladding layer 3b in the light emitting layer 5 is the barrier layer 5a, and the layer in contact with the second clad layer 7 of p-conduction type is the uppermost barrier layer 5c. Therefore, also in the quantum well layer 5b closest to each cladding layer, a so-called quantum well shape, that is, a potential depression is substantially the same as the other quantum well layers. Therefore, the wavelengths of light generated from each quantum well layer are substantially equal.
[0027]
On the light emitting layer 5, a second cladding layer (second semiconductor layer) 7 having a wider band gap than the barrier layer 5a is formed in two layers. The second cladding layer 7 has a thickness of 30.0 nm of magnesium doped p-Al _0.15 Ga _0.85 N layer 7a (carrier density: 1 to 2 × 10 ¹⁷ / cm ³ ) from below. The p-GaN layer 7b doped with 75.5 nm magnesium (carrier density: 2 × 10 ¹⁷ / cm ³ ) is used.
The thickness of the clad layer 7a containing Al is preferably 20 nm or more. If it is less than 20 nm, the effect of confining electrons by the hetero barrier is weakened. The cladding layer 7a need not be thicker than 100 nm.
[0028]
The second cladding layer 7 may be formed of _{Al A In B Ga 1-AB} N consisting (X = 0, Y = 0 , X = Y = 0 and including) compound semiconductor. The second cladding layer 7 can also be composed of one layer.
[0029]
A GaN layer 8 (carrier concentration: 1 × 10 ¹⁷ / cm ³ ) in which magnesium having a thickness of 25.0 nm is doped at a higher concentration than the p-GaN layer 7 b is formed on the second cladding layer 7. Yes. This layer is provided to reduce the contact resistance to the electrode. The film thickness of the GaN layer 8 is preferably 20 to 50 nm. If the film thickness is less than 20 nm, the effect of the contact layer is weakened and the resistance is increased. Further, it is not necessary to increase the film thickness beyond 50 nm.
[0030]
The electrode pad 9 is made of Al, Ti, or an alloy containing these.
Reference numeral 10 denotes a transparent electrode, which is formed on the GaN layer 8 over almost the entire surface. An electrode pad 11 is formed on the transparent electrode 10. Examples of the material for forming the transparent electrode 10 and the electrode pad 11 include Au, Pt, Pd, Ni, and alloys containing these.
[0031]
Next, the manufacturing method of the light emitting diode 20 of an Example is demonstrated.
Each semiconductor layer of the light emitting diode is formed by the MOVPE method. In this growth method, ammonia gas and a group III element alkyl compound gas such as trimethylgallium (TMG), trimethylaluminum (TMA) or trimethylindium (TMI) are supplied onto a substrate heated to an appropriate temperature. A desired crystal is grown on the substrate by a thermal decomposition reaction.
Note that the flow rate and reaction time of the carrier gas, ammonia gas, and group III element alkyl compound gas are appropriately adjusted according to the target crystal.
[0032]
First, the single crystal sapphire substrate 1 whose main surface is the surface a cleaned by organic cleaning and heat treatment is mounted on a susceptor in a gas phase reactor (not shown). Next, the sapphire substrate 1 is vapor-phase etched at a temperature of 1100 ° C. while N ₂ is allowed to flow through the reactor at normal pressure.
[0033]
Next, the temperature is lowered to 400 ° C., and N ₂ , NH ₃ and TMA are supplied to form the AlN buffer layer 2 on the substrate to a thickness of about 20 nm.
[0034]
Next, the temperature is raised, N ₂ , silane, TMG, and NH ₃ are introduced to form the lower layer 3a in the n-conducting semiconductor layer, and the upper layer 3b is formed by further reducing the flow rate of silane. .
[0035]
Subsequently, the temperature is maintained at 900 ° C., and N ₂ , TMG, and NH ₃ are introduced to form a barrier layer 5a made of GaN having a thickness of 3.5 nm. Next, the temperature is maintained at 750 ° C., and N ₂ , NH ₃ , TMG and TMI are introduced to form a quantum well layer 5b made of In _0.16 Ga _0.84 N having a thickness of 3.5 nm.
By repeating this, as shown in the figure, five barrier layers 5a and quantum well layers 5b are obtained.
The film thicknesses of the barrier layer 5a and the quantum well layer 5b are adjusted by adjusting the reaction time.
[0036]
The temperature is maintained at 900 ° C., and N _{2 ,} TMG, and NH ₃ are introduced to form an uppermost barrier layer 5c made of GaN having a thickness of 14.0 nm on the fifth-stage quantum well layer 5b. As described above, the upper surface of the uppermost barrier layer 5c disappears when the second cladding layer 7 is formed. In this example, the uppermost barrier layer 5c, which was initially 14.0 nm, became 3.5 nm after the formation of the second cladding layer.
The uppermost barrier layer 5c is preferably formed to have the same thickness as the other barrier layers 5a, that is, 3.5 nm after the formation of the second cladding layer.
[0037]
Next, the temperature is maintained at 1000 ° C., N ₂ , NH ₃ , TMG, TMA, CP ₂ Mg are introduced, and a layer 7 a made of p-Al _0.15 Ga _0.85 N doped with magnesium having a thickness of 30 nm is formed. Form. Next, the temperature is maintained at 1000 ° C., and N ₂ , NH ₃ , TMG, and CP ₂ Mg are introduced to form a p-GaN layer 7b doped with magnesium having a thickness of 75.0 nm. The clad layer 7 is formed.
[0038]
Following the formation of the layer 7b, the uppermost layer 8 is formed by changing the flow rate of CP ₂ Mg while maintaining the temperature at 1000 ° C.
[0039]
In this state, the second cladding layer 7 and the uppermost layer 8 are semi-insulating. Therefore, an electron beam is uniformly irradiated to the second cladding layer 7 and the uppermost layer 8 using an electron beam irradiation apparatus. The electron beam irradiation conditions are, for example, an acceleration voltage of about 10 kV, a sample current of 1 μA, a beam moving speed of 0.2 mm / sec, a beam diameter of 60 μmΦ, and a degree of vacuum of 5.0 × 10 ⁻⁵ Torr. By such electron beam irradiation, the second cladding layer 7 and the uppermost layer 8 become a desired p-conductivity type.
[0040]
The semiconductor wafer thus formed is etched by a known method to obtain the semiconductor layer structure shown in FIG. Then, the electrode pad 9 is formed on the semiconductor layer 3a by vapor deposition, then the gold transparent electrode 10 is vapor-deposited on the uppermost layer 8, and further the gold electrode pad 11 is vapor-deposited.
[0041]
The semiconductor wafer thus formed is cut into elements to obtain a desired blue light emitting diode 20.
[0042]
According to the study by the present inventors, the following characteristics were recognized in the device of the above-described embodiment.
FIG. 2 shows the change in the emission spectrum when the forward current applied to the device is changed. FIG. 3 is an analysis of the emission spectrum of FIG. 2 and shows changes in the peak wavelength and the half-value width when the forward current applied to the device is changed.
[0043]
As can be seen from these figures, the peak wavelength does not substantially change even when the current applied to the element is changed. That is, even if the current is changed in the range of 5 to 100 mA, the peak wavelength is approximately in the range of 445 to 450 nm. Considering a practical applied current to the device, the current applied in the forward direction is in the range of 5 to 50 mA, and when the current is changed in this range, the change in peak wavelength is 10 nm or less. 5 nm or less. In particular, the peak wavelength hardly changes in the current range of 20 to 50 mA.
[0044]
On the other hand, in a general light emitting device, when the applied current increases, that is, when the applied voltage increases, the peak wavelength shifts to the short wavelength side. The reason is considered as follows.
The semiconductor layer constituting the heterostructure light-emitting layer contains impurities. In such a semiconductor element, when the applied voltage is increased, carriers at the lowest energy level of the semiconductor layer are raised to the energy level formed by impurities contained in the light emitting layer. Since the level formed by this impurity is higher than the lowest energy level of the semiconductor layer, the wavelength of the light emitted by the recombination of the carriers is shifted to the short wavelength side.
Similarly, in a light-emitting layer having a single quantum well layer, when the applied voltage is increased, carriers that are at the lowest energy level of the quantum well are raised to a higher energy level in the quantum well. Therefore, the wavelength of light emitted by recombination of the carriers is shifted to the short wavelength side.
[0045]
On the other hand, according to the semiconductor light emitting device of this example, the light emitting layer is not doped with impurities. Furthermore, since there are a plurality of quantum well layers (5 layers in the embodiment), carriers at the lowest level of the quantum well are raised to a higher energy level within the quantum well when a high voltage is applied. In addition, tunneling is preferentially tunneled to the lowest energy level or the relatively low energy level that is vacant in other quantum wells that are continuous in the front and back (up and down in the figure). It is estimated that this prevents the wavelength shift to the short wavelength side.
From the viewpoint of preventing wavelength shift, the number of quantum well layers is preferably 3-7.
[0046]
Thus, it is preferable in terms of the characteristics of the light-emitting element that the peak wavelength is substantially constant even when the magnitude of the current is changed.
[0047]
The full width at half maximum of the emission spectrum is substantially constant irrespective of the applied current (5 to 100 mA), and is 60 nm or less. In the range of practical applied current (5 to 50 mA), the change in the full width at half maximum is further smaller. When the applied current is in the range of 20 to 50 mA, the change in the full width at half maximum is further reduced.
Since the half width is constant, it is considered that recombination of carriers at the same energy level contributes to light emission in each quantum well layer.
[0048]
As described above, the fact that the half width of the emission spectrum is maintained at 60 nm or less regardless of the change in the applied current means that the wavelength distribution of the emitted light is narrow and the emission is closer to the ideal monochromatic light. Means. As a result, a light emitting element with high color purity is obtained.
[0049]
Second Embodiment The semiconductor light emitting device of this embodiment is a green light emitting diode.
In the light emitting diode of this embodiment, the composition of the quantum well layer is In _0.23 Ga _0.77 N in the light emitting diode of the first embodiment. That is, the composition of In is made larger than that in the first embodiment. Such a quantum well layer is formed in the same manner as in the first embodiment, for example, by increasing the flow rate of TMI.
[0050]
According to the study by the present inventors, the following characteristics were recognized in the device of the above-described embodiment.
FIG. 4 shows the change in the emission spectrum when the forward current applied to the device is changed. FIG. 5 is an analysis of the emission spectrum of FIG. 4 and shows changes in peak wavelength and half-value width when the forward current applied to the device is changed.
[0051]
As can be seen from these figures, the peak wavelength does not substantially change even when the current applied to the element is changed. That is, even if the current is changed in the range of 5 to 100 mA, the peak wavelength is approximately in the range of 515 to 520 nm. Considering a practical applied current to the device, the current applied in the forward direction is in the range of 5 to 50 mA, and when the current is changed in this range, the change in peak wavelength is 10 nm or less. 5 nm or less. When the current range is 20 to 50 mA, and further 20 to 100 mA, the peak wavelength is almost 515 nm and hardly changes.
[0052]
The full width at half maximum of the emission spectrum is 60 nm or less, more specifically 35 nm or less, regardless of the applied current (5 to 100 mA). In the practical range of applied current (5 to 50 mA), the full width at half maximum hardly changes, and when the applied current range is set to 20 to 50 mA, the change in full width at half maximum becomes even smaller.
[0053]
The present invention is not limited to the description of the embodiments and examples of the invention described above, and includes various modifications that can be conceived by those skilled in the art without departing from the scope of the claims.
Of course, the present invention can also be applied to laser diodes.
[0054]
The following matters are disclosed below.
(1) A first semiconductor layer made of Al _X In _Y Ga _1-XY N (including X = 0, Y = 0, X = Y = 0), and an In _Y1 layer on the first semiconductor layer A light emitting layer having a superlattice structure formed by stacking a barrier layer made of Ga _{1 -Y1} N (Y1 ≧ 0), a quantum well layer made of In _Y2 Ga _{1 -Y2} N (Y2> Y1 and Y2> 0),
Keep the semiconductor light emitting device that includes a _{Al X In Y Ga 1-XY} N consisting (X = 0, Y = 0 , X = Y = 0 and including) the second semiconductor layer on the light emitting layer ,
In the light emitting layer, the layer in contact with the first semiconductor layer and the second semiconductor layer is the barrier layer.
[0055]
The semiconductor light emitting element according to (1), wherein the barrier layer in contact with the second semiconductor layer is thicker than other barrier layers.
[0056]
(11) a first semiconductor layer made of n-conducting GaN;
A barrier layer formed on the first semiconductor layer and made of In _Y1 Ga _{1 -Y1} N (Y1 ≧ 0) not doped with intentional impurities; In _Y2 Ga without intentional impurities doped A light-emitting layer having a superlattice structure formed by stacking quantum well layers made of _1-Y2 N (Y2> Y1 and Y2>0);
A second semiconductor layer formed on the light emitting layer and made of p-conductivity type AlGaN,
In the light emitting layer, the layer in contact with the first semiconductor layer and the second semiconductor layer is the barrier layer.
[0057]
(12) forming a _{Al X In Y Ga 1-XY} N first semiconductor layer made of (X = 0, Y = 0 , including X = Y = 0),
A barrier layer made of In _Y1 Ga _{1 -Y1} N (Y1 ≧ 0) and a quantum well layer made of In _Y2 Ga _{1 -Y2} N (Y2> Y1 and Y2> 0) are stacked on the first semiconductor layer. And forming a superlattice structure light emitting layer,
Semiconductor comprising the steps of forming a second semiconductor layer made of _{Al A In B Ga 1-AB} N on the light emitting layer (including A = 0, B = 0, A = B = 0), the In the method for manufacturing a light emitting device,
A method of manufacturing a semiconductor light emitting element, comprising forming an uppermost barrier layer, which is an uppermost layer of the light emitting layer, to be thicker than other barrier layers.
[0058]
(13) When forming the second semiconductor layer, the upper surface of the uppermost barrier layer is eliminated, and the thickness of the uppermost barrier layer is substantially the same as the thicknesses of the other barrier layers. (12) The method for producing a semiconductor light-emitting device according to (12).
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a light emitting diode according to an embodiment of the present invention.
FIG. 2 is a diagram showing a change in emission spectrum when a current is changed in a light emitting diode according to one embodiment of the present invention.
FIG. 3 is a diagram showing a change in peak wavelength and a change in half-value width when the current is similarly changed.
FIG. 4 is a diagram showing a change in emission spectrum when a current is changed in a light emitting diode according to another embodiment of the present invention.
FIG. 5 is a diagram showing a change in peak wavelength and a change in half-value width when the current is similarly changed.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Sapphire substrate 2 Buffer layer 3b 1st clad layer (1st semiconductor layer)
5 Light emitting layer 7 Second clad layer (second semiconductor layer)
20 Light emitting diode

Claims (1)

A method of manufacturing a semiconductor light emitting device by a MOVPE method,
Forming a first semiconductor layer made of _{Al X In Y Ga 1-XY} N ( including X = 0, Y = 0, X = Y = 0),
A step of laminating a barrier layer made of GaN and a quantum well layer made of InGaN on the first semiconductor layer to form a light emitting layer having a superlattice structure;
Forming a second semiconductor layer made of AlGaN on the light emitting layer, and a method for manufacturing a semiconductor light emitting device, comprising:
The method of manufacturing a semiconductor light emitting device characterized by the uppermost barrier layer serving as the uppermost layer formed thicker than the other barrier layers of the light-emitting layer.

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