JP2007243023A - Nitride semiconductor light-emitting element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nitride semiconductor light-emitting element that enables to obtain sufficient reliability under low-temperature and low-output conditions. <P>SOLUTION: The nitride semiconductor light-emitting element is composed so that a first coat film is formed on a light-emitting part and the first coat film includes an aluminum-oxide crystal. Here, it is also possible to form a second coated film made of aluminum nitride, aluminum oxynitride, silicon nitride, or silicon oxynitride between the light-emitting part and the first coat film. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a nitride semiconductor light emitting device, and more particularly to a nitride semiconductor light emitting device capable of obtaining sufficient reliability under low temperature and low output conditions.

  In general, a nitride semiconductor laser element among nitride semiconductor light emitting elements is known to have poor reliability due to deterioration of the light emitting portion on the end face on the light emitting side. It is said that the deterioration of the light emitting part is caused by excessive heat generation of the light emitting part due to the presence of the non-radiative recombination level. As a main factor for generating the non-radiative recombination level, oxidation of the light emitting portion is considered.

Therefore, for the purpose of preventing oxidation of the light emitting portion, a coat film such as alumina (Al ₂ O ₃ ) or silicon oxide (SiO ₂ ) is formed on the light emitting portion (see, for example, Patent Document 1). .
JP 2002-335053 A

  We have conducted research aiming to realize a nitride semiconductor laser device that does not cause poor reliability due to deterioration of the light emitting portion even during high-power driving.

  Conventionally, a coating film made of amorphous alumina is formed on the end face on the light emitting side to a thickness of 80 nm, and a multilayer film of silicon oxide film / titanium oxide film is formed on the end face on the light reflecting side to obtain a reflectance of 95%. The nitride semiconductor laser device was subjected to an aging test at a low output of 45 mW (pulse drive, pulse width 30 ns, duty 50%) at a low temperature of −10 ° C. As shown in FIG. It was found that the drive current fluctuated very much.

  When this conventional nitride semiconductor laser device is subjected to an aging test under the condition of a high output of 65 mW (pulse drive, pulse width 30 ns, duty 50%) at a high temperature of 60 ° C., the aging time is 1000 hours. Even in the case of exceeding the above, such drive current fluctuation did not occur.

  In general, the aging test under high temperature and high output conditions causes more damage to the light emitting part, so if reliability is ensured under high temperature and high output conditions, it can be used under low temperature and low output conditions. It has been considered that there is no problem with reliability. However, the above aging test confirmed that the idea was not necessarily correct. There are various environments in which nitride semiconductor laser elements are used, and it is necessary to ensure reliability even under conditions of low temperature and low output. This is considered to apply not only to the nitride semiconductor laser element but also to other nitride semiconductor light emitting elements such as a nitride semiconductor diode element.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a nitride semiconductor light emitting device capable of obtaining sufficient reliability under conditions of low temperature and low output.

  The present invention is characterized in that a first coat film is formed on the light emitting portion, and the first coat film is a nitride semiconductor light emitting element including an aluminum oxide crystal.

  Here, in the nitride semiconductor light emitting device of the present invention, the second coat film is formed between the light emitting portion and the first coat film, and the second coat film is made of aluminum nitride, aluminum oxynitride. , Silicon nitride or silicon oxynitride.

  In the nitride semiconductor light emitting device of the present invention, the thickness of the region where the aluminum oxide crystal is formed is preferably 10 nm or more.

  In the nitride semiconductor light emitting device of the present invention, the aluminum oxide crystal may be α-alumina.

  In the nitride semiconductor light emitting device of the present invention, the aluminum oxide crystal can be γ-alumina.

  The nitride semiconductor light emitting device of the present invention is a nitride semiconductor laser device, and the first coat film may be formed on the end surface of the nitride semiconductor laser device on the light emission side.

  The nitride semiconductor light emitting device of the present invention is a nitride semiconductor diode device, and a first coat film may be formed on the light emitting surface of the nitride semiconductor diode device.

  ADVANTAGE OF THE INVENTION According to this invention, the nitride semiconductor light-emitting device which can acquire sufficient reliability on the conditions of low temperature and low output can be provided.

  Embodiments of the present invention will be described below. In the drawings of the present invention, the same reference numerals represent the same or corresponding parts.

  As a result of intensive studies by the present inventors, it is possible to obtain sufficient reliability even under low temperature and low output conditions by forming the first coat film containing the aluminum oxide crystal on the light emitting portion of the nitride semiconductor light emitting device. The inventors have found what can be done and have completed the present invention.

  In addition, the inventor of the present invention provides an aluminum nitride, an aluminum oxynitride, a silicon nitride, or a silicon acid between the light emitting portion of the nitride semiconductor light emitting element and the first coat film containing an aluminum oxide crystal. It has been found that a nitride semiconductor light emitting device having sufficient reliability can be obtained even under the conditions of low temperature and low output even by forming the second coat film made of nitride.

  Here, the thickness of the region where the aluminum oxide crystal is formed in the first coat film is preferably 10 nm or more. In this case, the reliability of the nitride semiconductor light emitting element tends to be further improved under conditions of low temperature and low output. Of course, from the viewpoint of improving the reliability, it is preferable that the region where the aluminum oxide crystal is formed in the first coat film is located on the light emitting portion.

  In the present invention, the aluminum oxide crystal in the first coat film may be, for example, α-alumina that is a stable phase or γ-alumina, θ-alumina, δ-alumina, κ-alumina, χ that is a metastable phase. -Alumina, η-alumina or ρ-alumina may be mentioned, among which α-alumina or β-alumina is preferable from the viewpoint of improving the reliability of the nitride semiconductor light emitting device.

  Examples of the nitride semiconductor light emitting device of the present invention include a nitride semiconductor laser device and a nitride semiconductor light emitting diode device. In the nitride semiconductor light emitting device of the present invention, the active layer and the cladding layer formed on the substrate are at least one group 3 element and group 5 element selected from the group consisting of aluminum, indium and gallium. It means a light emitting device composed of a material containing 50% by mass or more of a compound with nitrogen.

  When the nitride semiconductor light emitting device of the present invention is a nitride semiconductor laser device, the light emitting portion is on the light emitting side end face of the nitride semiconductor laser device, and the first coat film is the nitride semiconductor laser device. It can be formed on the end surface of the light emission side. In the case where the nitride semiconductor light emitting device of the present invention is a nitride semiconductor diode device, the light emitting portion serves as the light emitting surface of the nitride semiconductor diode device, so that the first coat film emits light from the nitride semiconductor laser device. It can be formed on the surface. Here, the light emitting surface refers to a surface from which light is extracted from the nitride semiconductor diode element, and may be any of an upper surface, a lower surface, or a side surface of the nitride semiconductor diode element.

(Embodiment 1)
FIG. 1 shows a schematic cross-sectional view of a preferred example of the nitride semiconductor laser element of the present embodiment. Here, the nitride semiconductor laser device 100 according to the present embodiment includes a buffer layer 102 made of n-type GaN having a thickness of 0.2 μm and an n-type Al _0.06 Ga _0.94 N on a semiconductor substrate 101 made of n-type GaN. An n-type cladding layer 103 having a thickness of 2.3 μm, an n-type guide layer 104 having a thickness of 0.02 μm made of n-type GaN, a multiple quantum well active layer 105 made of InGaN having a thickness of 4 nm and GaN having a thickness of 8 nm, A p-type current blocking layer 106 having a thickness of 20 nm made of p-type Al _0.3 Ga _0.7 N, a p-type cladding layer 107 having a thickness of 0.5 μm made of p-type Al _0.05 Ga _0.95 N, and a thickness of 0.1 μm made of p-type GaN. A 1 μm p-type contact layer 108 is stacked by epitaxial growth in this order from the semiconductor substrate 101 side. In addition, the mixed crystal ratio of each said layer is adjusted suitably, and is not related to the essence of this invention. Further, the wavelength of the laser light oscillated from the nitride semiconductor laser element of the present embodiment is adjusted within the range of, for example, 370 nm to 470 nm by adjusting the mixed crystal ratio of the nitride semiconductor constituting the multiple quantum well active layer 105. It can be adjusted as appropriate. In the present embodiment, the wavelength of the laser light is 405 nm.

  Further, in the nitride semiconductor laser device 100 of the present embodiment, the p-type cladding layer 107 and the p-type contact layer 108 are partially removed so that the striped ridge stripe portion 111 extends in the cavity length direction. Is formed. Here, the width of the stripe of the ridge stripe portion 111 is, for example, about 1.2 to 2.4 μm, and typically about 1.5 μm.

Further, a p-electrode 110 made of a laminate of a Pd layer, a Mo layer, and an Au layer is provided on the surface of the p-type contact layer 108, and a SiO ₂ layer is formed below the p-electrode 110 except for a portion where the ridge stripe portion 111 is formed. An insulating film 109 made of a laminate of a layer and a TiO ₂ layer is provided. In addition, an n-electrode 112 made of a laminate of an Hf layer and an Al layer is formed on the surface of the semiconductor substrate 101 opposite to the layer on the layer side.

  FIG. 2 is a schematic side view of the nitride semiconductor laser element of the present embodiment shown in FIG. 1 in the cavity length direction. Here, a first coat film 114 containing γ-alumina is formed to a thickness of 80 nm on the end surface 113 on the light emission side of the nitride semiconductor laser device 100 of the present embodiment.

  Further, on the light reflecting side end face 115 of the nitride semiconductor laser device 100 of the present embodiment, an amorphous aluminum oxide film 116 having a thickness of 80 nm, a silicon oxide film having a thickness of 71 nm, and a titanium oxide film having a thickness of 46 nm are provided. 4 pairs are stacked (starting from the silicon oxide film), and a highly reflective film 117 in which a silicon oxide film having a thickness of 142 nm is stacked on the outermost surface is formed in this order.

  The first coat film 114, the aluminum oxide film 116, and the highly reflective film 117 are formed by sequentially stacking the nitride semiconductor layer such as a buffer layer on the semiconductor substrate and forming a ridge stripe portion. By cleaving the wafer on which the insulating film, the p-electrode, and the n-electrode are respectively formed, a sample with the end face 113 and the end face 115 that are cleavage faces exposed is produced, and formed on the end face 113 and the end face 115 of the sample, respectively. . Here, in the present embodiment, the first coat film 114 is formed by forming an amorphous aluminum oxide film (hereinafter referred to as “amorphous film”) on the end face 113 and then crystallizing a part of the amorphous film. Thus, the first coat film 114 containing γ-alumina is formed.

  Here, before the amorphous film is formed, the end surface 113 is heated at a temperature of, for example, 100 ° C. or higher in the film forming apparatus, thereby removing the oxide film or impurities attached to the end surface 113 and cleaning. Although it is preferable, it is not particularly necessary in the present invention. Further, the end face 113 may be cleaned by irradiating the end face 113 with, for example, argon or nitrogen plasma, but this is not particularly necessary in the present invention. It is also possible to irradiate plasma while heating the end face 113. As for the above-described plasma irradiation, for example, it is possible to irradiate nitrogen plasma after irradiating argon plasma, and the plasma may be irradiated in the reverse order. In addition to argon and nitrogen, for example, a rare gas such as helium, neon, xenon, or krypton can be used.

  The amorphous film can be formed by, for example, an ECR (Electron Cyclotron Resonance) sputtering method described below, but various other sputtering methods, a CVD (Chemical Vapor Deposition) method, an EB (Electron Beam) deposition method, or the like. Can also be formed.

  FIG. 3 shows a schematic configuration diagram of an example of an ECR sputtering film forming apparatus. Here, the ECR sputtering film forming apparatus includes a film forming chamber 200, a magnetic coil 203, and a microwave introduction window 202. A gas introduction port 201 and a gas exhaust port 209 are installed in the film forming chamber 200, and an Al target 204 and a heater 205 connected to an RF power source 208 are installed in the film forming chamber 200. A sample stage 207 is installed in the film forming chamber 200, and the sample 206 is installed on the sample stage 207. The magnetic coil 203 is provided for generating a magnetic field necessary for generating plasma, and the RF power source 208 is used for sputtering the Al target 204. Further, the microwave 210 is introduced into the film forming chamber 200 through the microwave introduction window 202.

  Then, oxygen gas is introduced into the film formation chamber 200 from the gas introduction port 201 at a flow rate of 6.5 sccm, and further, argon gas is supplied at 40.0 sccm in order to efficiently generate plasma and increase the film formation rate. Introduce at flow rate. Then, to sputter the Al target 204, 500 W of RF power is applied to the Al target 204, and 500 W of microwave power necessary for plasma generation is applied, the film formation temperature is set to 200 ° C., and the thickness on the end face 113 is 80 nm. An amorphous film was formed. Here, the amorphous film means that a part of the sample in which the amorphous film is formed on the end face 113 in the above is cut out, and the electron beam diffraction pattern by TEM is observed for the cut out amorphous film of the sample. This was confirmed from the fact that the diffraction pattern was a halo pattern.

  Further, the aluminum oxide film 116 and the high reflection film 117 on the light reflection side can also be formed by ECR sputtering or the like, similarly to the amorphous film. Also, it is preferable to perform cleaning by heating and / or cleaning by plasma irradiation before forming these films. However, the deterioration of the light emitting portion is a problem on the light emitting side where the light density is large, and the light reflecting side has a light density lower than that on the light emitting side, so that deterioration is not a problem in many cases. Therefore, in the present invention, it is not necessary to provide a film on the light reflecting side.

  Further, after the above film is formed on the end face, heat treatment may be performed. As a result, it is possible to expect an improvement in film quality due to the removal of moisture contained in the film and the heat treatment.

  As described above, an amorphous film is formed on the end face 113 of the sample, and an aluminum oxide film 116 and a highly reflective film 117 are formed on the end face 115 in this order, and then divided into a plurality of chips.

  Subsequently, the divided chips are aged for about 20 hours by CW driving under the condition of an optical output of 100 mW in a temperature environment of 70 ° C. When laser light is emitted under such high temperature and high output conditions, for example, as shown in the schematic diagram of FIG. 4, the amorphous film region 114 a on the light emitting portion 113 a in the end face 113 is crystallized, and γ-alumina Thus, the first coat film 114 is formed, and the nitride semiconductor laser device of the present embodiment is completed. At this time, since the amorphous film is formed with a thickness of 80 nm, the thickness of the region 114a in which the aluminum oxide crystal is formed in the first coat film 114 is 10 nm or more.

  FIG. 5 shows a schematic diagram of the electron diffraction pattern of the region 114a shown in FIG. 4 by TEM. From the electron beam diffraction pattern shown in FIG. 5, it was confirmed that the region 114a shown in FIG. 4 was composed of γ-alumina.

  The nitride semiconductor laser device of the present embodiment was subjected to an aging test under a low output condition of a light output of 45 mW (pulse drive, pulse width 30 ns, duty 50%) at a low temperature of −10 ° C. FIG. 6 shows drive current fluctuations in the aging test. As shown in FIG. 6, it was confirmed that the drive current hardly fluctuated until the aging time reached 300 hours. The reason why such a result was obtained is unknown, but when a coat film made of amorphous alumina is formed on the light emitting portion as in the conventional nitride semiconductor laser element, the thermal cycle is strongly applied, and the light It is considered that the reliability was lowered because the adhesion between the emitting portion and the coating film was lowered. On the other hand, in the nitride semiconductor laser device of the present embodiment, the first coat film in contact with the light emitting portion is crystallized, thereby improving the adhesion between the light emitting portion and the first coat film. It is thought that the reliability at low temperature and low output was improved.

  In this embodiment, in order to partially crystallize the amorphous film, the heat of the laser light generated by itself is used. For example, the above-described amorphous film is irradiated with excimer laser light or YAG laser light. By doing so, crystallization is possible.

(Embodiment 2)
FIG. 7 shows a schematic diagram of the nitride semiconductor laser device of the present embodiment. Here, the nitride semiconductor laser device of the present embodiment is characterized in that it is manufactured by directly forming the first coat film 114 made of γ-alumina on the end face 113.

  The method for fabricating the nitride semiconductor laser device of the present embodiment is the same as that of the first embodiment, but the first coat film 114 made of γ-alumina is formed on the end face 113 by the method described below.

  Here, an oxygen gas is introduced into the film formation chamber 200 from the gas inlet 201 shown in FIG. 3 at a flow rate of 6.5 sccm, and an argon gas is used to increase the film formation rate by efficiently generating plasma. At a flow rate of 40.0 sccm. Then, to sputter the Al target 204, 500 W of RF power is applied to the Al target 204 and 500 W of microwave power necessary for generating plasma is applied, the film forming temperature is set to 400 ° C., and γ-alumina is formed on the end face 113. A first coat film 114 made of was formed to a thickness of 80 nm. Here, the amorphous film means that a part of the sample in which the amorphous film is formed on the end face 113 in the above is cut out, and the electron beam diffraction pattern by TEM is observed for the cut out amorphous film of the sample. This was confirmed from the fact that the diffraction pattern was a halo pattern. The deposition rate of the first coat film 114 was 1.7 Å / second. In order to form the first coat film 114 made of γ-alumina, the deposition temperature is preferably 300 ° C. or higher, and more preferably 400 ° C. or higher.

  The nitride semiconductor laser device of the present embodiment was subjected to an aging test under a low output condition of a light output of 45 mW (pulse drive, pulse width 30 ns, duty 50%) at a low temperature of −10 ° C. Also in the nitride semiconductor laser element of the present embodiment, the drive current hardly fluctuated until the aging time reached 300 hours, as in the nitride semiconductor laser element of the first embodiment.

  In the present embodiment, the first coat film 114 made of γ-alumina is formed with a thickness of 80 nm. However, in the present invention, γ-alumina has a thickness of, for example, 30 nm on the side in contact with the end face 113. Alternatively, the first coat film 114 may be formed by forming a film made of amorphous aluminum oxide with a thickness of 50 nm thereon.

  Further, in the present embodiment, the first coating film 114 made of γ-alumina is formed by adjusting the film formation temperature. However, after forming an amorphous film on the end face 113, the first coating film 114 is also annealed at 400 ° C. or higher. The first coat film 114 made of alumina can also be formed. When the annealing temperature is increased, the first coat film 114 made of α-alumina as a stable phase, θ-alumina as a metastable phase, or δ-alumina can be formed. In the present specification, the first coat film containing γ-alumina in at least a part thereof is mainly described. However, a stable phase α-alumina, a metastable phase θ-alumina or δ is included in at least a part thereof. A first coat film containing alumina can also be used. In this case, since an annealing temperature of 800 ° C. or higher is required, it can be realized by annealing the amorphous film at 800 ° C. or higher and crystallizing it, and then manufacturing the p electrode and the n electrode. It is. Further, in addition to the above, the first coat film 114 may include a metastable phase of κ-alumina, χ-alumina, η-alumina, or ρ-alumina in at least a part thereof.

(Embodiment 3)
FIG. 8 shows a schematic diagram of the nitride semiconductor laser device of the present embodiment. Here, the nitride semiconductor laser element according to the present embodiment is an aluminum compound represented by a composition formula of Al _x O _y N _z (x + y + z = 1, 0 ≦ y ≦ 0.35) (aluminum when y = 0). A second coating film 118 made of nitride of aluminum, and an oxynitride of aluminum when 0 <y ≦ 0.35) is sandwiched between the end face 113 and the first coating film 114 made of γ-alumina. The third coat film 119 made of amorphous aluminum oxide is formed on the first coat film 114. Here, the thickness of the second coat film 118 can be set to, for example, 20 nm, the thickness of the first coat film 114 can be set to, for example, 20 nm, and the thickness of the third coat film 119 can be set to, for example, 160 nm. be able to.

  In the above composition formula, Al represents aluminum, O represents oxygen, and N represents nitrogen. In the above composition formula, x represents the composition ratio of aluminum, y represents the composition ratio of oxygen, and z represents the composition ratio of nitrogen.

  For example, when the second coat film 118 made of aluminum oxynitride or aluminum nitride and the third coat film 119 made of amorphous aluminum oxide are formed in this order on the end face 113, a low temperature of −10 ° C. It was found that the drive current greatly fluctuated in the aging test under the low output condition where the light output was 45 mW (pulse drive, pulse width 30 ns, duty 50%). This is presumably because the adhesion between the second coat film 118 made of oxynitride or nitride and the third coat film 119 made of oxide is low.

  Therefore, as a result of intensive studies by the present inventors, the first coating film 114 made of amorphous aluminum oxide is interposed on the second coating film 118 made of aluminum oxynitride or aluminum nitride via the first coating film 114 made of γ-alumina. By forming the 3-coat film 119, it is possible to reduce fluctuations in the drive current in the aging test under the low output condition of 45 mW (pulse drive, pulse width 30 ns, duty 50%) at a low temperature of −10 ° C. all right. This is because the first coat film 114 made of γ-alumina is formed between the second coat film 118 made of oxynitride or nitride and the third coat film 119 made of oxide. It is considered that the adhesion can be improved.

  In the present embodiment, the oxygen composition ratio y of the second coat film 118 is 0 ≦ y ≦ 0.35, but the present invention is not limited to this. However, when y> 0.35, the adhesion between the first coat film 114 and the third coat film 119 tends to improve, but the first coat film 114 and the second coat film 118 Therefore, the oxygen composition ratio y of the second coat film 118 is preferably in the range of 0 ≦ y ≦ 0.35.

Further, in this embodiment, as the second coat film 118 an aluminum compound represented by the composition formula of _{Al x O y N z (x} + y + z = 1,0 ≦ y ≦ 0.35), Al x instead of _{O y N z (x + y} + z = 1,0 ≦ y ≦ 0.35) of the composition aluminum compound represented by the formula, the composition of _{Si a O b N c (a} + b + c = 1,0 ≦ b ≦ 0.35) A silicon compound represented by the formula (silicon nitride when b = 0, silicon oxynitride when 0 <b ≦ 0.35) can also be used. Here, the composition ratio b of oxygen in the second coat film 118 is not limited to the range of 0 ≦ y ≦ 0.35, but for the same reason as above, the range of 0 ≦ y ≦ 0.35. It is preferable that it exists in. In the above composition formula, Si represents silicon, O represents oxygen, and N represents nitrogen. In the above composition formula, a represents the composition ratio of silicon, b represents the composition ratio of oxygen, and c represents the composition ratio of nitrogen.

(Embodiment 4)
The nitride semiconductor laser element of the present embodiment has the same configuration as that of the nitride semiconductor laser element of the first embodiment except that the wavelength of the oscillated laser beam is 460 nm. In the nitride semiconductor laser device of the present embodiment, the wavelength of the oscillated laser beam was adjusted by changing the mixed crystal ratio of the nitride semiconductor constituting the multiple quantum well active layer 105.

  The nitride semiconductor laser device of the present embodiment was subjected to an aging test under a low output condition of a light output of 45 mW (pulse drive, pulse width 30 ns, duty 50%) at a low temperature of −10 ° C. As a result, also in the nitride semiconductor laser element of the present embodiment, the drive current hardly changed until the aging time reached 300 hours, as in the nitride semiconductor laser element of the first embodiment. Therefore, it has been found that the present invention can also be applied to a nitride semiconductor laser element in which the wavelength of the oscillated laser beam is 460 nm. Such a nitride semiconductor laser element that oscillates laser light having a wavelength of 460 nm can be used as an excitation light source for an illumination device.

  In the first to fourth embodiments described above, the case where the nitride semiconductor light emitting device of the present invention is a nitride semiconductor laser device has been described. However, the nitride semiconductor light emitting device of the present invention is a nitride semiconductor diode device. In some cases, by forming the first coat film 114 on the light emitting surface of the nitride semiconductor diode element, the reliability under low temperature and low output conditions can be improved as in the case of the nitride semiconductor laser element. It is thought that you can.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  ADVANTAGE OF THE INVENTION According to this invention, the nitride semiconductor light-emitting device which can acquire sufficient reliability on the conditions of low temperature and low output can be provided.

2 is a schematic cross-sectional view of a preferred example of the nitride semiconductor laser element according to the first embodiment. FIG. FIG. 2 is a schematic side view of the nitride semiconductor laser element according to the first embodiment shown in FIG. 1 in the cavity length direction. It is a typical block diagram of an example of an ECR sputtering film-forming apparatus. 4 is a schematic diagram of the nitride semiconductor laser element of the first embodiment in the cavity length direction. FIG. FIG. 3 is a schematic diagram of an electron diffraction pattern of a crystallized region of a first coat film of the nitride semiconductor laser element according to the first embodiment. For the nitride semiconductor laser device of the first embodiment, the drive current when the aging test was performed under the low output condition of 45 mW (pulse drive, pulse width 30 ns, duty 50%) at a low temperature of −10 ° C. It is a figure which shows fluctuation | variation. FIG. 6 is a schematic diagram of the nitride semiconductor laser element of the second embodiment in the cavity length direction. 6 is a schematic diagram of a cavity length direction of a nitride semiconductor laser element according to a third embodiment. FIG. FIG. 5 shows fluctuations in drive current when a conventional nitride semiconductor laser device is subjected to an aging test at a low output of 45 mW (pulse drive, pulse width 30 ns, duty 50%) at a low temperature of −10 ° C. FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100 Nitride semiconductor laser element, 101 Semiconductor substrate, 102 Buffer layer, 103 n-type clad layer, 104 n-type guide layer, 105 Multiple quantum well active layer, 106 p-type current block layer, 107 p-type clad layer, 108 p-type Contact layer, 109 insulating film, 110 p electrode, 111 ridge stripe part, 112 n electrode, 113, 115 end face, 113a light emitting part, 114 first coat film, 116 aluminum oxide film, 117 highly reflective film, 118 second coat Film, 119 Third coat film, 200 Deposition chamber, 201 Gas introduction port, 202 Microwave introduction window, 203 Magnetic coil, 204 Al target, 205 Heater, 206 Sample, 207 Sample stage, 208 RF power supply, 209 Gas exhaust port 210 microwave.

Claims (7)

  A nitride semiconductor light emitting device, wherein a first coat film is formed on a light emitting portion, and the first coat film contains an aluminum oxide crystal.   A second coat film is formed between the light emitting portion and the first coat film, and the second coat film is made of aluminum nitride, aluminum oxynitride, silicon nitride, or silicon oxynitride. The nitride semiconductor light emitting device according to claim 1, wherein the nitride semiconductor light emitting device is made of a material.   The nitride semiconductor light-emitting element according to claim 1 or 2, wherein a thickness of the region where the aluminum oxide crystal is formed is 10 nm or more.   The nitride semiconductor light-emitting element according to claim 1, wherein the aluminum oxide crystal is α-alumina.   The nitride semiconductor light-emitting element according to claim 1, wherein the aluminum oxide crystal is γ-alumina.   2. The nitride semiconductor light emitting element is a nitride semiconductor laser element, and the first coat film is formed on an end surface of the nitride semiconductor laser element on a light emitting side. 6. The nitride semiconductor light emitting device according to any one of 5 above.   6. The nitride semiconductor light emitting device according to claim 1, wherein the nitride semiconductor light emitting device is a nitride semiconductor diode device, and the first coat film is formed on a light emitting surface of the nitride semiconductor diode device. A nitride semiconductor light emitting device according to claim 1.

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