JP5444609B2 - Semiconductor laser element - Google Patents

Description

  The present invention relates to a semiconductor laser device, and more particularly to a semiconductor laser device having a structure in which light is confined by a current blocking layer.

Conventionally, for example, in _{In x Al y Ga 1-xy} N (0 ≦ x, 0 ≦ y, 0 ≦ x + y ≦ 1) blue-violet semiconductor laser comprising a compound semiconductor, the vertical direction of the light in the active layer In order to sufficiently increase the confinement factor, methods for increasing the Al composition of the cladding layer have been studied. However, when the Al composition is increased, there is a problem that strain is inherent in the Al-containing layer due to lattice mismatch with the substrate and other compound semiconductor layers, and cracks are generated.
On the other hand, by disposing a current blocking layer having stripe-shaped grooves and a transparent electrode functioning as a cladding layer on the active layer, the growth time of the compound semiconductor layer is shortened, and the compound semiconductor layer is made thinner. A semiconductor laser device that can reduce the occurrence of cracks in the Al-containing layer has been proposed (for example, Patent Document 1).
JP 2006-41491 A

However, in this semiconductor laser device, since the transparent electrode formed on the current blocking layer extends to the cavity end face, the device has been devised to improve the cleavage and orientation. There is a problem that it becomes difficult to produce the resonator surface due to the accompanying cleavage.
When current is injected to the end face of the resonator by such a transparent electrode, heat is generated in the vicinity of the end face of the resonator, and heat generation becomes particularly significant in a high-power element, so there is a concern that the COD level may be lowered. .
In addition, if the transparent electrode is formed away from the resonator end surface for manufacturing the resonator surface and improving the COD level, the vertical optical confinement coefficient near the resonator end surface changes, so that the refractive index in the resonator direction is changed. The distribution changes, and the FFP (Far Field Pattern) in the vertical direction is disturbed.

  The present invention has been made in view of the above problems. Even in a high-power semiconductor laser element, heat generation at the cavity end face can be minimized, the COD level can be improved, and a good FFP shape can be obtained. An object of the present invention is to provide a semiconductor laser device that can be obtained, has high reliability, and has a long lifetime.

The semiconductor laser device of the present invention is
A laminate composed of a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer;
A current blocking layer having a stripe-shaped groove parallel to the resonator direction in contact with the second conductivity type semiconductor layer;
A dielectric is embedded on the resonator end face side in the groove, and a conductive oxide is embedded inside the dielectric in the groove,
The dielectric have a refractive index in the range of the refractive index ± 0.5 of the conductive oxide, and wherein the Rukoto such formed of a different material from that of the current blocking layer.
Another semiconductor laser element is
A laminate composed of a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer;
A current blocking layer having a stripe-shaped groove parallel to the resonator direction in contact with the second conductivity type semiconductor layer;
A dielectric is embedded on the resonator end face side in the groove, and a conductive oxide made of ITO is embedded inside the dielectric in the groove,
The dielectric is a material selected from the group consisting of ZrO ₂ , SiO ₂ , Al ₂ O ₃ , Nb ₂ O ₃ , TiO ₂ , Ta ₂ O ₅ , AlN and SiN, and the current blocking layer It is formed of different materials .

In this semiconductor laser device, the dielectric and the current blocking layer are preferably formed of different materials.
The dielectric preferably has a refractive index c that is greater than or equal to the refractive index a of the current blocking layer and / or smaller than the refractive index d of the active layer.
Furthermore, the conductive oxide preferably has a refractive index b that is greater than or equal to the refractive index a of the current blocking layer and / or smaller than the refractive index d of the active layer.
The dielectric is preferably formed of a material selected from the group consisting of ZrO ₂ , SiO ₂ , Al ₂ O ₃ , Nb ₂ O ₃ , TiO ₂ , Ta ₂ O ₅ , AlN and SiN.
The current blocking layer is preferably formed of a material selected from the group consisting of SiO ₂ , Ga ₂ O ₃ , Al ₂ O ₃ , ZrO ₂ , SiN, AlN, and AlGaN.
The dielectric preferably has a refractive index in the range of refractive index ± 1 of the conductive oxide layer.
The current blocking layer is preferably made of a material having a refractive index smaller than that of the active layer and the conductive oxide layer.
The oscillation wavelength is preferably 440 nm or more.
And a second current blocking layer having a striped groove parallel to the resonator direction in contact with the first conductivity type layer, and a dielectric is embedded on the resonator end face side of the groove, It is preferable that a conductive oxide layer is embedded inside.

  According to the semiconductor laser device of the present invention, even in a high-power semiconductor laser device, heat generation at the cavity end face can be minimized, the COD level can be improved, and a good FFP can be obtained. Therefore, it is possible to provide a semiconductor laser device with high reliability and long life.

  The semiconductor laser device of the present invention is constituted by a laminated body including a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer.

The first conductivity type semiconductor layer is not particularly limited, but is a compound semiconductor, further a nitride semiconductor, in particular, the general formula is In _x Al _y Ga _1-xy N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, Those represented by 0 ≦ x + y ≦ 1) are preferred. In addition to this, an element in which B is partially substituted as a group III element may be used, or an element in which a part of N is substituted with P or As may be used as a group V element. One of the first conductivity type and the second conductivity type means n-type, and the other means p-type. The n-type semiconductor layer may contain one or more group IV elements or group VI elements such as Si, Ge, Sn, S, O, Ti, Zr, and Cd as n-type impurities. The p-type semiconductor layer contains Mg, Zn, Be, Mn, Ca, Sr, etc. as p-type impurities. The impurities are preferably contained in a concentration range of, for example, about 5 × 10 ¹⁶ / cm ³ to 1 × 10 ²¹ / cm ³ . Note that all of the semiconductor layers constituting the first conductivity type semiconductor layer and the second conductivity type semiconductor layer do not necessarily contain impurities.

  The first conductive type semiconductor layer and / or the second conductive type semiconductor layer preferably have a light guide layer, and further, an SCH (Separate Confinement Heterostructure) structure in which these light guide layers sandwich an active layer. A structure is preferable. The light guide layer of the first conductivity type semiconductor layer and the light guide layer of the second conductivity type semiconductor layer may have structures having different compositions and / or film thicknesses.

  For example, a first conductive semiconductor layer (hereinafter may be referred to as “n-type semiconductor layer or n-side semiconductor layer”), an active layer, a second conductive semiconductor layer (hereinafter referred to as “p-type semiconductor layer or p-side semiconductor”). May be described as a single film structure, a multilayer film structure, or a superlattice structure composed of two layers having different composition ratios. These layers may be provided with a composition gradient layer and a concentration gradient layer.

The n-type semiconductor layer may have a structure of two or more layers having different compositions and / or impurity concentrations.
For example, the first n-type semiconductor layer can be formed of In _x Al _y Ga _1-xy N (0 ≦ x <1, 0 ≦ y ≦ 1, 0 ≦ x + y ≦ 1), preferably Al _x Ga _1-x N (0 ≦ x ≦ 0.5), more preferably Al _x Ga _1-x N (0 <x ≦ 0.3). As specific growth conditions, it is preferable to form the growth temperature in the reactor at 900 ° C. or higher. The first n-type semiconductor layer can function as a cladding layer. A film thickness of about 0.5 to 5 μm is appropriate. As will be described later, when a conductive oxide film having a low refractive index is provided on the n-type semiconductor layer side, the first n-type semiconductor layer can be omitted.
The second n-type semiconductor layer can function as a light guide layer, and is represented by In _x Al _y Ga _1-xy N (0 ≦ x <1, 0 ≦ y <1, 0 ≦ x + y ≦ 1). Can be formed. The film thickness is suitably from 0.1 to 5 μm. The second n-type semiconductor layer can be omitted.
One or more semiconductor layers may be additionally formed between the n-type semiconductor layers.

The active layer may have either a multiple quantum well structure or a single quantum well structure. The well layer preferably has a general formula In _x Al _y Ga _1-xy N (0 ≦ x ≦ 1, 0 ≦ y <1, 0 ≦ x + y ≦ 1) containing at least In. Increasing the In content makes it possible to emit light in the long wave region, and increasing the Al content makes it possible to emit light in the ultraviolet region, and it is possible to emit light in the wavelength region of about 300 nm to 650 nm. Luminous efficiency can be improved by forming the active layer with a quantum well structure.

A p-type semiconductor layer is stacked on the active layer.
The first p-type semiconductor layer can be formed of Al _x Ga _1-x N (0 ≦ x ≦ 0.5) containing p-type impurities. The first p-type semiconductor layer functions as a p-side electron confinement layer.
The second p-type semiconductor layer can function as a light guide layer, and is represented by In _x Al _y Ga _1-xy N (0 ≦ x <1, 0 ≦ y <1, 0 ≦ x + y ≦ 1). Can be formed.

On the second p-type semiconductor layer, a super lattice layer made of Al _x Ga _1-x N (0 ≦ x ≦ 0.5) or GaN and AlGaN containing a p-type impurity functioning as a cladding layer is formed. This layer can be omitted. By omitting this layer, the growth time of the p-side semiconductor layer after the active layer growth can be omitted. In general, in order to reduce the resistance of the p-side semiconductor layer, the p-side semiconductor layer is preferably stacked at a higher temperature than the n-side semiconductor layer or the active layer. However, when the p-side semiconductor layer is grown at a high temperature, the active layer having a high In mixed crystal ratio may be decomposed. Therefore, by omitting this layer, damage to the active layer caused by growing the p-side semiconductor layer at a high temperature can be reduced. Furthermore, since the number of stacked p-side semiconductor layers having high resistance can be reduced, the operating voltage can be reduced.

The third p-type semiconductor layer can be formed of Al _x Ga _1-x N (0 ≦ x ≦ 1) containing a p-type impurity.
These semiconductor layers may be mixed with In. The first p-type semiconductor layer and the second p-type semiconductor layer can be omitted. The thickness of each layer is suitably about 3 nm to 5 μm.
Note that one or more semiconductor layers may be additionally formed between p-type semiconductor layers.

  In a semiconductor laser having a relatively long wavelength of 440 nm or more, it is necessary to increase the Al mixed crystal in the p-side and / or n-side cladding layers in order to provide a sufficient refractive index difference. In a semiconductor laser that oscillates light in the ultraviolet region of 380 nm or less, light absorption can be prevented by forming a layer with a high Al mixed crystal. However, when a layer having a high Al mixed crystal is formed, cracks are likely to occur in the semiconductor layer. Therefore, by omitting the cladding layer, a highly reliable long-wavelength semiconductor laser with reduced cracks can be realized.

  The growth method of the semiconductor layer is not particularly limited, but MOVPE (metal organic chemical vapor deposition), MOCVD (metal organic chemical vapor deposition), HVPE (hydride vapor deposition), MBE (molecular beam epitaxy), etc. All methods known as nitride semiconductor growth methods can be used. In particular, MOCVD is preferable because it can be grown with good crystallinity under reduced pressure to atmospheric pressure.

  In the semiconductor laser device of the present invention, as shown in FIG. 1, a current blocking layer is formed in contact with the p-type semiconductor layer, that is, on the p-type semiconductor layer. The current blocking layer is usually preferably formed as a layer parallel to the active layer. The current blocking layer has a stripe-shaped groove, and the groove extends in parallel to the resonator direction. The groove portion may be terminated inside the resonator end face, but preferably reaches the resonator end face and is in an open state. However, as shown in FIG. 6 (a), when the current blocking layer is formed of the same material as the dielectric described later, it is not necessarily an open end, and is on the extension line to the resonator end face of the groove. In the vicinity of the resonator end face of the current blocking layer (A in FIG. 6), a part of the current blocking layer may be disposed as a dielectric.

  The width of the groove is, for example, about 0.3 to 50 μm, and preferably about 1 to 5 μm when a single mode laser is manufactured. The end face of the current blocking layer in the resonator direction does not necessarily coincide exactly with the end face of the resonator, but is preferably coincident. The end face of the current blocking layer other than in the resonator direction may coincide with the end face of the stacked body, but is preferably disposed inside the end face of the stacked body. The bottom surface of the groove in the current blocking layer is in contact with the semiconductor layer. That is, the depth of the groove corresponds to the thickness of the current blocking layer.

The current blocking layer includes a semiconductor layer (for example, refractive index of GaN: about 2.5), in particular, an active layer (for example, refractive index of InAlGaN: about 2.1 to 3.5) and a conductive oxide layer described later. It is suitable that the refractive index a is smaller than that. By having such a refractive index, light can be reliably confined in the waveguide.
Alternatively, it is suitable to be made of a material having a barrier higher than the driving voltage of the semiconductor laser element. Here, having a barrier equal to or higher than the driving voltage means that the insulating properties of the semiconductor can be maintained. By having such a barrier, a stable and good electrical characteristic and a long-life semiconductor laser can be expected.

The current blocking layer is made of, for example, oxide and nitride, specifically, SiO ₂ (refractive index: about 1.5), Ga ₂ O ₃ , Al ₂ O ₃ , ZrO ₂ , SiN, AlN, and AlGaN. It can be formed of an insulating material selected from a group and a group including an i-type semiconductor layer. A film thickness is not specifically limited, For example, about 0.05-5 micrometers is mentioned. The current blocking layer may be a single layer or a multilayer.

The current blocking layer may be formed in the same manner as described above in contact with the n-type semiconductor layer instead of the p-type semiconductor layer, or in contact with the p-type semiconductor layer and the n-type semiconductor layer. In this case, the groove, the dielectric and conductive oxide described later are usually formed in the same manner.
In the present specification, the refractive index means a value at a wavelength of 445 nm, and the refractive index usually indicates a value measured by an ellipsometer.

  The current blocking layer can be formed by a method known in the art. For example, evaporation method, sputtering method, reactive sputtering method, ECR plasma sputtering method, magnetron sputtering method, ion beam assisted evaporation method, ion plating method, laser ablation method, CVD method, spray method, spin coating method, dip method or Various methods such as a method of combining two or more of these methods or a method of combining these methods and oxidation treatment (heat treatment) can be used.

Examples of film formation conditions for the current blocking layer include sputtering using silicon oxide or silicon as a target when forming a current blocking layer (eg, SiO ₂ ). At this time, argon gas, a mixed gas of argon gas and oxygen gas, or the like can be used as appropriate. Also, as a sputtering gas, a method of switching from a gas having a small or zero oxygen partial pressure to a gas having a large oxygen partial pressure, a method of reducing a film formation rate, a method of increasing RF power, or a change in the distance between the target and the substrate And a method of forming a film by a method of reducing the pressure. Furthermore, when forming the protective film by sputtering, a method of increasing or decreasing the temperature of the substrate may be used. Thereafter, an optional heat treatment may be performed.

  The conductive oxide layer is formed so as to fill at least the groove portion of the current blocking layer. The conductive oxide layer may be formed over the current blocking layer as shown in FIGS. 1 (a) to 1 (d), or as shown in FIGS. 5 (c) and 5 (c ′). It may be embedded only inside. In the conductive oxide layer, the end face in the resonator direction is arranged on the inner side of the resonator end face in the active layer (see 11 in FIGS. 5 (b ') to (d')). That is, the end surface in the resonator direction is separated from the resonator end surface in the active layer. As a result, the conductive oxide layer does not affect the cleavage of the stack of semiconductor layers, and it is possible to reliably cleave in the intended direction and obtain a good resonator end face. In order to obtain a good resonator end surface, it is sufficient that the conductive oxide layer is formed away from the resonator end surface on at least one of the pair of opposed end surfaces. Preferably it is. The distance is not particularly limited. For example, when the resonator length is about 400 to 1500 μm, the length is about 0.001 to 10%, specifically about 0.1 to 10 μm. It is suitable to arrange inside. The end face of the conductive oxide layer other than in the resonator direction may coincide with the end face of the stacked body, but is preferably disposed inside the end face of the stacked body.

  The conductive oxide layer is in contact with the second conductivity type semiconductor layer in the groove and functions as an ohmic electrode. The conductive oxide layer embedded in the groove of the current blocking layer functions as a cladding layer that confines light in the desired laser waveguide due to the difference in refractive index between the current blocking layer and the conductive oxide layer. .

For example, the conductive oxide layer preferably has a refractive index b that is greater than or equal to the refractive index a of the current blocking layer and / or has a refractive index b smaller than the refractive index d of the active layer. The conductive oxide layer can be formed of, for example, a layer containing at least one element selected from the group consisting of zinc (Zn), indium (In), tin (Sn), and magnesium (Mg). Specific examples include ZnO (refractive index: about 1.95), In ₂ O ₃ , SnO ₂ , ATO, ITO (a composite oxide of In and Sn), MgO, and the like. Of these, ITO (refractive index: about 2.0) is preferable.

This conductive oxide film efficiently absorbs not only visible light but also, for example, light having a wavelength of 360 nm to 650 nm, for example, a transmittance of 90% or more, 85% or more, 80% or more. It is preferable that light can be transmitted. Thereby, it can utilize as an electrode of the semiconductor laser element of the intended wavelength. Furthermore, the conductive oxide film has a specific resistance of, for example, 1 × 10 ⁻³ Ωcm or less, preferably about 1 × 10 ⁻⁴ to 1 × 10 ⁻⁶ Ωcm. Thereby, it can utilize effectively as an electrode.
The thickness of the conductive oxide layer is not particularly limited, and can be appropriately adjusted depending on the material used, the thickness of the current blocking layer, and the like. For example, about 0.1-4.0 micrometers is mentioned.

  For example, as shown in FIG. 5A, the conductive oxide layer is formed on the entire surface of the semiconductor laminate 14 (11 in FIG. 5A), and is usually used for photolithography and etching processes. It can be formed by patterning into a desired shape using the method (see FIGS. 5 (b) and (b ′), FIG. 4 (c) and (c ′) or FIG. 6 (b)). . Alternatively, a mask layer may be formed in advance on the semiconductor layer, a conductive oxide layer may be formed thereon, and the lift-off method may be used.

  The conductive oxide layer can be formed by a method known in the art. For example, various methods such as a sputtering method, an ion beam assisted deposition method, an ion implantation method, an ion plating method, a laser ablation method, or a combination of these methods and heat treatment can be used.

  Specifically, when a conductive oxide film, for example, an ITO film is formed by sputtering, the sputtering partial gas is switched from a gas having a small or zero oxygen partial pressure to a gas having a large oxygen partial pressure. In addition to the ITO deposition target, a method using a target with a large amount of In or a target with a small amount of oxygen, and a method of switching to a target with a large amount of In or a target with a small amount of oxygen on the way, For example, a method of forming a film by gradually or rapidly increasing the input power. In addition, when a conductive oxide film such as an ITO film is formed by vacuum deposition, a method of rapidly or gradually increasing or decreasing the temperature of the semiconductor layer, a method of rapidly decreasing the film formation rate, an ion gun And a method of irradiating oxygen ions from the middle of the film formation.

  Further, a dielectric is embedded in the groove portion of the current blocking layer from the end face of the conductive oxide layer to the end face of the resonator. That is, in the groove provided in the current blocking layer, the dielectric is embedded on the resonator end face side of the groove, and the conductive oxide is embedded inside. The dielectric should just be provided in at least one of the both ends of the groove. Preferably, it is provided at both ends. In that case, a dielectric, a conductive oxide, and a dielectric are formed in this order in the direction of the resonator in the groove.

  As described above, by disposing the dielectric film on the resonator end face side separately from the conductive oxide layer, the conductive oxide layer in the vicinity of the end face of the resonator may be peeled off or cleaved. In addition, the adhesion by the end face with the conductive oxide layer can be improved, and light confinement can be ensured. As a result, distortion of the laser beam emitted from the resonator end face can be prevented, and a good FFP pattern can be obtained. In addition, the flow of current to the resonator end face can be minimized, generation of heat at the resonator end face can be suppressed, and the COD level can be improved. In particular, when an attempt is made to increase the output of the laser element, the heat generation becomes large, but the heat generation at the cavity end face where the heat generation is particularly remarkable can be reduced.

  In other words, when the conductive oxide is formed up to the vicinity of the resonator end face, a minute leak occurs near the end face of the resonator, the power consumption increases, the heat generation of the laser element increases, and the deterioration rate increases. Thus, the element life is shortened. Further, when the vicinity of the cavity end face is opened and the semiconductor layer is exposed, the nitride semiconductor laser has a refractive index difference with the semiconductor layer near the cavity face, and the beam emitted from the laser faces downward. Disturbance is seen in the FFP shape. On the other hand, by embedding a dielectric in the vicinity of the resonator surface as in the present invention, a semiconductor laser with good element reliability and FFP shape can be obtained.

  For example, the dielectric preferably has a refractive index c that is greater than or equal to the refractive index a of the current blocking layer, has a refractive index c smaller than the refractive index d of the active layer, or satisfies both. In particular, the dielectric is suitable to have a refractive index close to that of the conductive oxide layer. For example, the dielectric preferably has a refractive index in the range of ± 1, preferably ± 0.5. In addition, it is preferable that the dielectric is made of a material different from that of the current blocking layer and is formed of a material having a higher refractive index than that of the current blocking layer because light scattering can be suppressed and the threshold value can be lowered. From another viewpoint, it is preferably made of a material having a barrier higher than the driving voltage of the semiconductor laser element.

Dielectrics are, for example, oxides and nitrides, specifically, ZrO ₂ , SiO ₂ (refractive index: about 1.45), Al ₂ O ₃ , Nb ₂ O ₃ , TiO ₂ , Ta ₂ O ₅ , It can be formed of a material selected from the group consisting of AlN and SiN, and among them, ZrO ₂ and SiO ₂ are preferable. In particular, when the dielectric is formed of an oxide, adhesion with the conductive oxide can be formed satisfactorily. Further, when the dielectric is an insulating material and has a refractive index close to that of a conductive oxide (for example, ITO), the optical confinement is improved and a laser beam having a desired beam shape is obtained. This is preferable. The dielectric may be a single layer, or a plurality of materials having different compositions may be laminated to obtain an appropriate refractive index.

The film thickness of the dielectric is not particularly limited and can be adjusted as appropriate depending on the composition of the material, the refractive index, and the like, and is preferably about the same as the conductive oxide layer. Specifically, about 0.1-2.0 micrometers is mentioned.
The dielectric material only needs to be embedded in at least the groove portion of the current blocking layer, and may be disposed on the current blocking layer. The end faces other than the direction of the resonator may coincide with the end faces of the laminate and / or the current blocking layer, or may be disposed inside.

The dielectric is preferably provided from the end face of the resonator to the end face of the conductive oxide in the resonator direction.
When the dielectric is provided after the conductive oxide is provided, the conductive oxide may be coated. When the resonator length is about 200 to 1500 μm, it is suitable that the length is about 0.006 to 5%, specifically about 0.1 to 10 μm.

  The dielectric is preferably formed of an oxide and provided with a region where the conductive oxide film and the dielectric are in contact with each other. Thereby, the adhesiveness between the conductive oxide and the dielectric member can be improved, and light confinement in the vicinity of the resonator surface can be ensured. This is effective when the current blocking layer is formed of an oxide.

  Such a dielectric is formed, for example, before or after forming the conductive oxide 11 as shown in FIGS. 4 (c ′) and (d ′) and FIGS. 5 (c ′) and (d ′). Formed by forming a mask (not shown) in which a region for forming dielectric 10 is opened, forming dielectric 10 thereon, peeling the mask, and leaving dielectric 10 in the groove. be able to. When the conductive oxide 11 is formed in the whole resonator direction, the conductive oxide 11 in the vicinity of the resonator end face is removed by etching or the like, and then the dielectric 10 is formed by the same method as described above. May be formed.

Further, as shown in FIGS. 4E ′ and 4E ″, the dielectric 10 is formed by wrapping the material of the end face protective film at the same time as forming the end face protective film described later on the resonator end face. Can be formed by arranging them in the groove.
4D and 4E are cross-sectional views in the direction of the resonator at the groove.
Furthermore, as shown in FIG. 6A, when this dielectric is formed of the same material as that of the current blocking layer 9, the groove near the resonator end face is covered when the current blocking layer 9 is formed. By forming the current blocking layer 9 on (see A in FIG. 6A), a part of the current blocking layer 9 can be disposed as a dielectric.
The dielectric can be formed by a method known in the art similar to the current blocking layer. The film formation conditions can be the same as the film formation conditions for the current blocking layer described above.

In the semiconductor laser device of the present invention, the above-mentioned laminated body of semiconductor layers is usually formed on a substrate. The substrate may be an insulating substrate such as sapphire or spinel (MgA1 ₂ O ₄ ), or lithium niobate or neodymium gallate that is lattice-bonded to silicon carbide, silicon, ZnS, ZnO, GaAs, diamond, or a nitride semiconductor. The substrate may be an oxide substrate such as a nitride semiconductor substrate (GaN, AlN, etc.).
More preferably, the nitride semiconductor substrate has, for example, an off angle of about 0.03 to 10 ° on the first main surface and / or the second main surface. The thickness is about 50 μm to 10 mm. The nitride semiconductor substrate can be formed by vapor phase growth methods such as MOCVD method, HVPE method, MBE method, hydrothermal synthesis method for crystal growth in a supercritical fluid, high pressure method, flux method, melting method and the like. A commercially available product may also be used.

  The nitride semiconductor substrate may be one in which dislocation density is periodically distributed in a stripe pattern in one surface. For example, a low dislocation density region (for example, a first region) and a high dislocation density region (for example, a second region) are alternately formed in stripes by using the ELO method, and a semiconductor layer is formed on a substrate by lateral growth. By forming and using this semiconductor layer as a substrate, a region in which crystal defect densities, crystal directions, and the like are arranged in a stripe shape can be used. Further, regions having different polarities may be distributed. For example, the polarity may be divided in a stripe shape in the first region and the second region.

Here, the low dislocation density region is a region where the number of dislocations per unit area is 1 × 10 ⁷ / cm ² or less, preferably 5 × 10 ⁶ / cm ² or less. As long as the region has a high dislocation density.
When the first region and the second region alternately form stripes, the width of the first region is 10 μm to 500 μm, further 100 μm to 500 μm, and the width of the second region is 2 μm to 100 μm, 10 μm to 50 μm. It is done. The stripe shape includes a stripe shape. These dislocation measurements can be performed by CL observation, TEM observation, or the like.

  The nitride semiconductor substrate may have different crystal growth surfaces distributed on one surface thereof. For example, if the first area is the (0001) plane, the second area is different from the (0001) plane (000-1) plane, (10-10) plane, (11-20) plane, (10-14) And crystal growth planes such as a plane, a (10-15) plane, and a (11-24) plane. In particular, the (000-1) plane is preferable. By using a substrate having a partially different crystal growth surface in this way, stress and strain generated in the substrate can be relaxed, and a semiconductor layer can be formed without forming a stress relaxation layer on the substrate. Lamination can be performed with a film thickness of 5 μm or more.

As the nitride semiconductor substrate, for example, those described in JP-A-2005-175056, JP-A-2004-158500, JP-A-2003-332244, etc. may be used.
Note that a buffer layer, an intermediate layer, and the like (for example, Al _x Ga _1-x N (0 ≦ x ≦ 1) and the like) are provided over the substrate before forming a stacked body that functions as a laser element. Is preferred.

  In the semiconductor laser device of the present invention, it is preferable to form a side surface protective film that covers at least both sides of the stacked body of semiconductor layers. The side protective film is preferably formed over the surface of the conductive oxide layer by opening a region connected to the outside. The side surface protective film may also serve as a current blocking layer or may serve as a dielectric. Such a side surface protective film is preferably formed after the conductive oxide is formed and before the pad electrode described later is formed.

  Examples of the material of the side surface protective film include oxides and nitrides such as Ti, Al, Zr, V, Nb, Hf, Ta, Ga, and Si. The method for forming the side surface protective film is known in the art, and can be formed in a single layer or a laminated structure by various methods such as CVD, vapor deposition, ECR (electron cyclotron resonance plasma) sputtering, and magnetron sputtering. . A single-layer film may be formed as a film having the same composition but different film quality by changing the manufacturing method or conditions once or twice or more, or a laminated film of these materials It is good.

  A pad electrode is usually formed on the surface of the conductive oxide layer. The pad electrode is preferably a laminated film made of a metal such as Ni, Ti, Au, Pt, Pd, or W. Specifically, a film formed in the order of W—Pd—Au or Ni—Ti—Au and Ni—Pd—Au from the conductive oxide layer side can be given. The film thickness of the pad electrode is not particularly limited, but the film thickness of the final layer of Au is preferably about 100 nm or more.

  When the substrate is a conductive substrate, for example, an n electrode is preferably formed on the back surface of the substrate. The n electrode can be formed by, for example, sputtering, CVD, vapor deposition, or the like. As the n electrode, for example, the total film thickness is about 1 μm or less, and from the substrate side, V (film thickness 100 mm) -Pt (film thickness 2000 mm) -Au (film thickness 3000 mm), Ti (100 mm) -Al (5000 mm) Ti (60 （)-Pt (1000Å) -Au (3000Å), Ti (60Å) -Mo (500Å) -Pt (1000Å) -Au (2100Å), Ti (60Å) -Hf (60Å) -Pt (1000Å) -Au (3000?), Ti (60?)-Mo (500?)-Ti (500?)-Pt (1000?)-Au (2100?), W-Pt-Au, W-Al-W-Au, or Hf-Al Ti-W-Pt-Au, Ti-Pd-Pt-Au, Pd-Pt-Au, Ti-W-Ti-Pt-Au, Mo-Pt-Au, Mo-Ti-Pt-Au, W-Pt -A , V-Pt-Au, V-Mo-Pt-Au, V-W-Pt-Au, Cr-Pt-Au, Cr-Mo-Pt-Au, Cr-W-Pt-Au, etc. The

  Further, a metallized electrode may be optionally formed on the n electrode. The metallized electrodes are, for example, Ti—Pt—Au— (Au / Sn), Ti—Pt—Au— (Au / Si), Ti—Pt—Au— (Au / Ge), Ti—Pt—Au—In, It can be formed of Au—Sn, In, Au—Si, Au—Ge, or the like. The film thickness of the metallized electrode is not particularly limited.

In the semiconductor laser device of the present invention, the resonator end face is usually formed by cleaving the substrate and the laminate.
Optionally, an end face protective film made of a dielectric film is preferably formed on the resonator end face, that is, on the light reflection side and / or the light exit face of the resonator face. The dielectric film is preferably a single layer film or a multilayer film made of oxides and nitrides such as SiO ₂ , ZrO ₂ , TiO ₂ , Al ₂ O ₃ , Nb ₂ O ₅ , AlN, and AlGaN. When the resonance surface is formed by cleavage, the dielectric film can be formed with good reproducibility.
This end face protective film can be formed as a dielectric by wrapping around from the end face of the resonator to the groove on the end face side of the resonator.

Furthermore, the semiconductor laser device of the present invention may have a structure in which the above-described current blocking layer and conductive oxide layer are arranged in a pair with an active layer interposed therebetween.
The laser element having such a structure is formed on the above-described substrate, for example, by removing the substrate from the stacked body of the semiconductor layer in which the current blocking layer, the conductive oxide layer, and the dielectric are formed, or n-type. A part of the semiconductor layer (for example, up to the cladding layer or the light guide layer) is removed, and a current blocking layer, a conductive oxide layer, and a dielectric are formed on the removed side in the same manner as described above. be able to.

Hereinafter, embodiments of the semiconductor laser device of the present invention will be described in detail based on the drawings.
Example 1
In the semiconductor laser device of this embodiment, as shown in FIGS. 1A to 1D, an n-type semiconductor layer, an active layer 5, and a p-type semiconductor layer are stacked on a substrate 1, and a p-type semiconductor is formed. On the layer, a current blocking layer 9 having a stripe-shaped groove near the center is formed. In addition, a conductive oxide layer 11 is formed in the groove portion of the current blocking layer 9 and in contact with the p-type semiconductor layer and extending over the current blocking layer 9. In the conductive oxide layer 11, both end faces in the resonator direction are spaced inward from the resonator end faces. Dielectric layers 10 are disposed on both ends of the groove portion in the groove portion of the current blocking layer 9 from the resonator end surface to the end surface of the conductive oxide 11. A p-pad electrode 12 is formed on the conductive oxide 11, and an n-electrode 13 is formed on the back surface of the substrate 1.

A method for manufacturing this semiconductor laser element will be described below.
First, a substrate 1 made of n-type GaN is set in a MOVPE reaction vessel, and trimethylaluminum (TMA), trimethylgallium (TMG), ammonia (NH ₃ ), silane gas (SiH ₄ ) is used as impurity gas, and Si is doped. The n-type cladding layer 3 made of Al _0.33 Ga _0.67 N was grown.
Subsequently, an n-side light guide layer 4 made of undoped GaN was grown at the same temperature using TMG and ammonia.

At a temperature of 950 ° C., a barrier layer made of In _0.02 Ga _0.98 N doped with Si was grown using trimethylindium (TMI), TMG, and ammonia. The well layer made of undoped In _0.06 Ga _0.94 N is grown by stopping the silane gas and using TMI, TMG and ammonia. After repeating this twice, a barrier layer made of In _0.02 Ga _0.98 N is grown using TMI, TMG and ammonia at the same temperature, and an active layer made of two pairs of multiple quantum wells (MQW) 5 (refractive index: about 2.5) was grown.

Stop TMI, use TMA, TMG and ammonia, flow biscyclopentadienylmagnesium (Cp ₂ Mg), grow p-type cap layer 6 made of Mg-doped p-type Al _0.30 Ga _0.70 N I let you.
Subsequently, Cp ₂ Mg and TMA were stopped, and a p-side light guide layer 7 made of undoped GaN was grown at 1050 ° C.
Finally, a p-type contact layer 8 made of p-type GaN doped with Mg was grown on this by flowing Cp ₂ Mg using TMG and ammonia.

Next, a current blocking layer 9 (refractive index: about 1.5) made of SiO _{2 having a} thickness of about 500 nm was formed by CVD on the wafer on which the semiconductor laminate 14 was formed (see FIG. 4A). .
Subsequently, a photoresist having a stripe-shaped opening (stripe width of about 5 μm) is formed on the current blocking layer 9, and the current blocking layer is formed by wet etching using, for example, BHF using the photoresist as a mask. 9 was selectively removed to form a groove 15 whose bottom reaches the semiconductor layer. The groove 15 is formed so as to be open in the resonator direction (see FIGS. 4B and 4B). Thereafter, the photoresist was removed.

  Thereafter, a conductive oxide layer 11 (refractive index: about 2.0) made of ITO was formed on the entire surface of the current blocking layer 9 including the groove 15. A photoresist is formed thereon so that about 5 μm is exposed from the end face of the resonator. RIE was performed using this photoresist as a mask, and a part of the conductive oxide layer was selectively removed so that the semiconductor layer was exposed in the trench 15. As a result, the semiconductor layer was exposed in the range of 5 μm from the cavity end face side of the groove 15 (see FIGS. 4C and 4C).

Next, a dielectric (thickness: about 400 nm) made of ZrO ₂ was formed on the exposed semiconductor layer and photoresist. Thereafter, by removing the photoresist, the dielectric 10 made of ZrO ₂ was embedded in the groove 15 (see FIGS. 4D ′ and 4D ″). Thereby, the groove provided in the current blocking layer. Inside, a dielectric can be embedded in the cavity end face side of the groove, and a conductive oxide can be embedded inside.
At this time, by forming the photoresist formed on the conductive oxide layer 11 made of ITO so as to be separated from the side surface of the nitride semiconductor laser element, the side surface protective film made of ZrO ₂ can be simultaneously formed. it can.
Thereafter, in order to reduce the contact resistance of the p-type semiconductor layer, for example, annealing was performed at 600 ° C. in an oxygen atmosphere.

A p-pad electrode 12 was formed on the conductive oxide layer 11.
Further, the back surface of the substrate 1 was polished, and an n-electrode 13 was formed on the polished back surface of the n-type GaN substrate 1.
Thereafter, the GaN substrate 1 was cleaved along, for example, a direction perpendicular to the direction of the resonator to make the wafer into a bar shape, and a resonator surface was produced on the cleavage surface of the bar.
Subsequently, a dielectric film is formed as an end face protective film on the resonator surface. On the light emitting side, Al ₂ O ₃ was formed with a film thickness of 70 nm. On the opposite side, a multilayer dielectric film was formed of a laminated film of ZrO ₂ and SiO ₂ (total film thickness 700 nm).
Finally, it was divided in a direction parallel to the resonator surface, and a bar-shaped wafer was chipped to obtain a semiconductor laser device.

Example 2
As in Example 1, a conductive oxide layer 11 made of ITO was formed to a thickness of 0.4 μm on the wafer on which the semiconductor laminate 14 was formed by using a sputtering method (see FIG. 5A). ).
Thereafter, a striped photoresist (stripe width is about 5 μm and length is about 10 μm shorter than the resonator length of the semiconductor laminate 14) is formed on the conductive oxide layer 11. Using this photoresist as a mask, the conductive oxide layer 11 exposed from the photoresist is removed by, for example, reactive ion etching (RIE) using HI gas. As a result, a stripe-shaped conductive oxide layer 11 was formed (see FIGS. 5B and 5B). Here, the conductive oxide layer 11 was formed so that the end face opposed to the resonator direction was disposed about 5 μm inside the resonator end face of the stacked body of semiconductor layers.

Next, a current blocking layer 9 (refractive index: about 1.5) made of SiO ₂ having a thickness of about 400 nm was formed on the exposed semiconductor layer and photoresist by sputtering. At the same time, a side surface protective film can be formed. Next, the photoresist and the current blocking layer 9 formed thereon were removed. Thereby, the conductive oxide layer 11 is embedded only in the groove portion of the current blocking layer 9.
Subsequently, a photoresist was formed so as to expose a region where a dielectric was to be formed. Then, the exposed current blocking layer was removed by wet etching to expose the semiconductor layer (see FIGS. 5C and 5C).
A dielectric was formed on the exposed semiconductor layer and photoresist by sputtering. Thereafter, the photoresist was removed. As a result, the dielectric 10 was buried in the groove 15 on the resonator surface side facing the dielectric 10 (see FIG. 5 (d ′)).

Further, when the region for forming the dielectric is exposed, the photoresist may be temporarily removed, and the photoresist may be formed separately from the region for forming the dielectric and the side surface of the nitride semiconductor laser element. Thereby, the side surface protective film made of ZrO ₂ can be formed on the side surface protective film made of SiO ₂ formed at the same time as the dielectric. At this time, the dielectric is formed on the semiconductor layer, the photoresist, and the current blocking layer.
Thereafter, a semiconductor laser element was formed in the same manner as in Example 1.

Comparative Example 1
As shown in FIG. 3A, this laser element does not form a dielectric oxide film layer but substantially embeds a conductive oxide layer 11 in a groove provided in the current blocking layer 9. A laser element having the same configuration as in Example 1 was formed by the same method as in Example 1.

Comparative Example 2
As shown in FIG. 3B, this laser element does not form a dielectric oxide film layer, and is in a groove provided in the current blocking layer 9 so as to coincide with the end face of the resonator. A laser element having substantially the same configuration as that of Example 2 was formed by the same method as that of Example 2 except that the conductive oxide layer 11 was embedded.

For each of the laser elements obtained in Examples 1 and 2 and Comparative Examples 1 and 2, the FFP intensity distribution, COD level, and life test in the vertical direction were performed.
As a result, as shown in FIGS. 7A to 7C, the FFP intensity distribution in the vertical direction is the laser of Example 1 and Comparative Example 2 as shown in the order of Example 1 and Comparative Examples 1 and 2, respectively. With the device, good results of about the same degree were obtained, but it was confirmed that the laser device of Comparative Example 1 was distorted in the vertical confinement and a stable FFP could not be obtained.
Further, at the COD level, as shown in Table 1, the laser element of Example 2 was the highest, and the laser elements of Example 1 and Comparative Example 1 were almost as high. On the other hand, in the laser element of Comparative Example 2, a low result was obtained. The COD level was measured for 20 laser elements of each example and comparative example, and the average value of 18 samples excluding the maximum and minimum values was shown.

Furthermore, in the life test, as shown in FIG. 8 (Example 2) and FIG. 9 (Comparative Example 2), it was confirmed that the laser element of Example 2 operates stably.
On the other hand, in Comparative Example 2, it was confirmed that sudden oscillation stopped.
In the life test, a semiconductor laser element having an oscillation wavelength of 408 nm was driven under the conditions of an operating temperature of 25 ° C., an output of 500 mW, and APC driving, and a change with time in the driving current value (driving current value / initial driving current value) was measured. .

As described above, in the semiconductor laser elements of Examples 1 and 2, the dielectric oxide film is reliably disposed near the resonator end face separately from the conductive oxide layer, so that the conduction in the vicinity of the resonator end face is achieved. The confinement of light can be ensured without causing troubles such as peeling and cleavage of the conductive oxide layer and with good adhesion by the end face with the conductive oxide layer. Therefore, distortion of the laser beam emitted from the cavity end face can be prevented, and a good FFP pattern can be obtained.
In addition, the flow of current to the resonator end face can be minimized, generation of heat at the resonator end face can be suppressed, and the COD level can be improved.
In particular, in the semiconductor laser device of Example 2, as shown in FIG. 5, since the conductive oxide layer is formed by RIE, the shape controllability is improved, and the conductive oxide layer is placed at a desired position. It can be formed with high accuracy, and the COD level can be improved.
Further, it is possible to extend the life.

  On the other hand, in the semiconductor laser device of Comparative Example 1, the FFP intensity distribution in the vertical direction is disturbed due to a sudden change in the confinement factor near the resonator surface, and it is difficult to drive the laser device for a long time. Was confirmed. Further, the semiconductor laser element of Comparative Example 2 induces end face deterioration due to energization in the vicinity of the end face, and the result that the COD level is low compared with the other is obtained, and it is difficult to drive the laser element for a long time. It was confirmed.

Example 3
Similar to Example 1, a current blocking layer 9 having a groove and a conductive oxide layer 11 are formed on a wafer on which a semiconductor laminate is formed.
Thereafter, similarly to Example 1, a p-pad electrode 12 and an n-electrode 13 are formed, and the GaN substrate 1 is cleaved to produce a resonator surface.
Subsequently, a dielectric film is formed on the resonator surface. On the light emitting side, Al ₂ O ₃ is formed with a film thickness of 70 nm. On the opposite side, a multilayer dielectric film is formed of a laminated film of ZrO ₂ and SiO ₂ (total film thickness 700 nm). At this time, by forming a dielectric film so that the Al ₂ O ₃ film wraps around the upper surface of the element, the dielectric layer 10 is embedded in the groove 15 in the vicinity of the resonator end face (FIG. 4 (e ′) and ( e ")).
Thereafter, a semiconductor laser element is formed in the same manner as in Example 1.
Thereby, the same effect as Example 1 can be acquired.

Example 4
As in Example 1, the current blocking layer 9 is formed on the wafer on which the semiconductor laminate is formed, and a photoresist having a stripe-shaped opening (stripe width is about 5 μm) is formed. At this time, the opening of the photoresist is opened from a position about 5 μm away from both resonator end faces. Using this photoresist as a mask, for example, by wet etching using BHF, a part of the current blocking layer 9 is selectively removed, and a groove portion whose bottom reaches the semiconductor layer is formed (FIG. 6A). Middle, see A). As a result, the vicinity of the resonator end face of the groove is buried by the current blocking layer and can function as the dielectric layer 10.
Thereafter, the conductive oxide layer 11 is formed in the same manner as in Example 1 (see FIG. 6B).
Thereafter, a semiconductor laser element is formed in the same manner as in Example 1.

In the semiconductor laser device of this example, as in Example 1, the conductive oxide layer in the vicinity of the cavity end face does not peel off, causes cleavage, and other problems, and depends on the end face with the conductive oxide layer. Adhesion can be improved and light confinement can be ensured. As a result, distortion of the laser beam emitted from the cavity end face can be prevented, a good FFP pattern can be obtained, and a longer life can be achieved.
In addition, the flow of current to the resonator end face can be minimized, generation of heat at the resonator end face can be suppressed, and the COD level can be improved.

Example 5
In the semiconductor laser device of this embodiment, a conductive oxide film is formed at a distance of about 10 μm from both end faces of the resonator, and a dielectric is applied to the exposed semiconductor layer from the end face of the conductive oxide layer to the end face of the resonator. Embed. Other than that, a semiconductor laser element is formed in the same manner as in the first embodiment.
In the semiconductor laser device of this embodiment, the same effect as that of Embodiment 1 can be obtained.

Example 6
In the semiconductor laser device of this embodiment, a conductive oxide film is formed with a distance of about 15 μm from both end faces of the resonator, and a dielectric is applied to the exposed semiconductor layer from the end face of the conductive oxide layer to the end face of the resonator. Embed. Other than that, a semiconductor laser element is formed in the same manner as in the first embodiment.
In the semiconductor laser device of this embodiment, the same effect as that of Embodiment 1 can be obtained.

Example 7
In the semiconductor laser device of this embodiment, a conductive oxide film is formed only on the light emitting side resonator end face with a spacing of about 5 μm, and a dielectric is formed on the exposed semiconductor layer from the end face of the conductive oxide layer to the end face of the resonator. Embed the body. Other than that, a semiconductor laser element is formed in the same manner as in the first embodiment.
Even in the semiconductor laser device of this embodiment, the same effect as that of Embodiment 1 can be obtained.

Example 8
In the semiconductor laser device of this embodiment, the conductive oxide film is formed so as to be separated from the light emitting side resonator end face by about 5 μm and from the reflecting side resonator end face by about 10 μm. A dielectric is embedded in the exposed semiconductor layer from the end face of the conductive oxide layer to the end face of the resonator. Other than that, a semiconductor laser element is formed in the same manner as in the first embodiment.
Even in the semiconductor laser device of this embodiment, the same effect as that of Embodiment 1 can be obtained.

Example 9
In the semiconductor laser device of this example, the semiconductor laser device is formed in the same manner as in Example 1 except that the width of the groove is set to 10 μm.
In the semiconductor laser device of this embodiment, in addition to the same effects as those of Embodiment 1, it is possible to increase the output by widening the groove.
In other words, when the output of the laser element is increased, heat generation generally increases.However, by widening the groove portion in this way, it is possible to reduce heat generation particularly at the cavity end face where heat generation is remarkable, The COD level can be obtained.

Example 10
In the semiconductor laser device of this example, the semiconductor laser device is formed in the same manner as in Example 1 except that the dielectric is AlN.
In the semiconductor laser device of this example, the same effect as that of Example 1 can be obtained.

なお、本願表中、「ｎ−」は、ｎ型不純物のドープを示し、「ｐ−」は、ｐ型不純物のドープを示す。
この実施例の半導体レーザ素子では、実施例１と同様の効果を得ることができる。 Example 11
In the semiconductor laser device of this example, each semiconductor layer is configured as shown in Table 2, and a laminated body is formed according to Example 1 except that the laser element has an oscillation wavelength of about 440 to 450 nm. Similarly, a semiconductor laser element is formed.

In the table of the present application, “n−” indicates doping of n-type impurities, and “p−” indicates doping of p-type impurities.
In the semiconductor laser device of this embodiment, the same effect as that of Embodiment 1 can be obtained.

この実施例の半導体レーザ素子では、実施例１と同様の効果を得ることができる。 Example 12
In the semiconductor laser device of this example, each semiconductor layer is configured as shown in Table 3 below, and a laminated body is formed in accordance with Example 1 except that the laser element has an oscillation wavelength of about 370 to 380 nm. A semiconductor laser element is formed in the same manner as in 1.

In the semiconductor laser device of this embodiment, the same effect as that of Embodiment 1 can be obtained.

Example 13
In the semiconductor laser device of this embodiment, as shown in FIGS. 2A to 2D, an n-type semiconductor layer, an active layer 5, and a p-type semiconductor layer are stacked, and on the p-type semiconductor layer, Near the center, a current blocking layer 9 having a stripe-shaped groove is formed. In addition, a conductive oxide layer 11 is formed in the groove portion of the current blocking layer 9 and in contact with the p-type semiconductor layer and extending over the current blocking layer 9. The conductive oxide layer 11 has an end face in the resonator direction that is spaced inward from the end face of the resonator. The dielectric layer 10 is disposed in the groove portion of the current blocking layer 9 from the end face of the resonator to the end face of the conductive oxide 11. A p-pad electrode 12 is formed on the conductive oxide 11.
In addition, a current blocking layer 9 having a stripe-shaped groove is formed near the center of the n-type semiconductor layer. Similarly to the above, in the groove of the current blocking layer 9, the n-type semiconductor A conductive oxide layer 11 is formed which contacts the layer and extends over the current blocking layer 9. The conductive oxide layer 11 has an end face in the resonator direction that is spaced inward from the end face of the resonator. The dielectric layer 10 is disposed in the groove portion of the current blocking layer 9 from the end face of the resonator to the end face of the conductive oxide 11. An n pad electrode 13 is formed on the conductive oxide 11.

A method for manufacturing this semiconductor laser element will be described below.
Similar to the first embodiment, after the semiconductor layer stack, the current blocking layer 9, the conductive oxide layer 11, and the dielectric 10 are formed, the substrate to the n-type cladding layer 3 are removed by polishing.
A current blocking layer 9, a conductive oxide layer 11, and a dielectric 10 are formed on the surface of the obtained n-clad layer 3 in the same manner as in Example 1.
Thereafter, the p pad electrode 12, the n electrode 13 and the like are formed in the same manner as in the first embodiment.

  As in Example 1, the obtained semiconductor laser device has good adhesion between the conductive oxide layer and the end face, can ensure light confinement, and can generate heat at the end face of the resonator. In addition, the COD level can be suppressed, a good FFP pattern can be obtained, and the life can be extended.

  The present invention can be used not only for a laser element but also for a method for manufacturing a light emitting element such as a light emitting diode (LED).

It is (a) perspective view, (b) front view, (c) plan view, and (d) side view showing the structure of the semiconductor laser device of the present invention. It is (a) perspective view, (b) front view, (c) top view, (d) side view showing the structure of another semiconductor laser device of the present invention. It is a top view which shows the structure of the semiconductor laser element for a comparison. It is a schematic manufacturing process figure of the principal part for demonstrating the manufacturing method of the semiconductor laser element of this invention. It is a schematic manufacturing-process figure of the principal part for demonstrating another manufacturing method of the semiconductor laser element of this invention. It is a schematic manufacturing-process figure of the principal part for demonstrating another manufacturing method of the semiconductor laser element of this invention. It is a graph which shows the FFP intensity | strength of the semiconductor laser element of this invention, and the laser element for a comparison. It is a graph which shows the life characteristic of the semiconductor laser element of this invention. It is a graph which shows the life characteristic of the semiconductor laser element for a comparison.

Explanation of symbols

1 substrate 3 n-type cladding layer 4 n-side light guide layer 5 active layer 6 cap layer 7 p-side light guide layer 8 p-type contact layer 9 current blocking layer 10 dielectric layer 11 conductive oxide layer 12 p-pad electrode 13 n Electrode 14 Laminate 15 Groove

Claims (11)

A laminate composed of a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer;
A current blocking layer having a stripe-shaped groove parallel to the resonator direction in contact with the second conductivity type semiconductor layer;
A dielectric is embedded on the resonator end face side in the groove, and a conductive oxide is embedded inside the dielectric in the groove,
Said dielectric is a semiconductor laser device characterized Rukoto such is formed of a different material than the have a refractive index in the range of the refractive index ± 0.5 of the conductive oxide, and said current blocking layer. A laminate composed of a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer;
A current blocking layer having a stripe-shaped groove parallel to the resonator direction in contact with the second conductivity type semiconductor layer;
A dielectric is embedded on the resonator end face side in the groove, and a conductive oxide made of ITO is embedded inside the dielectric in the groove,
The dielectric is a material selected from the group consisting of ZrO ₂ , SiO ₂ , Al ₂ O ₃ , Nb ₂ O ₃ , TiO ₂ , Ta ₂ O ₅ , AlN and SiN, and the current blocking layer A semiconductor laser element formed of different materials .   3. The semiconductor laser device according to claim 1, wherein the dielectric has a refractive index c that is greater than or equal to the refractive index a of the current blocking layer and / or smaller than the refractive index d of the active layer.   The semiconductor laser device according to claim 1, wherein the conductive oxide has a refractive index b that is greater than or equal to the refractive index a of the current blocking layer and / or smaller than the refractive index d of the active layer. 2. The dielectric according to claim 1, wherein the dielectric is formed of a material selected from the group consisting of ZrO ₂ , SiO ₂ , Al ₂ O ₃ , Nb ₂ O ₃ , TiO ₂ , Ta ₂ O ₅ , AlN and SiN. Semiconductor laser device. Said current blocking _layer, any one of the preceding claims comprising formed of a material selected from _{SiO 2, Ga 2 O 3,} Al 2 O 3, ZrO 2, SiN, the group consisting of AlN and AlGaN The semiconductor laser device described in 1. Said current blocking layer, a semiconductor laser device according to any one of claims 1-6 having a refractive index than the active layer and the conductive oxide layer is made of material having low. The semiconductor laser device according to the oscillation wavelength of any one of claims 1 to 7 is more than 440 nm. And a second current blocking layer having a striped second groove parallel to the resonator direction in contact with the first conductivity type layer, the second current blocking layer being located on the resonator end face side in the second groove. second dielectric is embedded, any one of claims 1-8 in which the second conductive oxide layer is buried inside the second dielectric of said second groove portion The semiconductor laser device described in 1. A laminate composed of a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer;
A current blocking layer having a stripe-shaped groove parallel to the resonator direction in contact with the second conductivity type semiconductor layer;
A dielectric is embedded on the resonator end face side in the groove, and a conductive oxide is embedded inside the dielectric in the groove,
The dielectric has a refractive index in the range of refractive index ± 0.5 of the conductive oxide,
And a second current blocking layer having a striped second groove parallel to the resonator direction in contact with the first conductivity type layer, the second current blocking layer being located on the resonator end face side in the second groove. 2. A semiconductor laser device, wherein a second dielectric oxide is embedded, and a second conductive oxide layer is embedded inside the second dielectric in the second groove. A laminate composed of a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer;
  A current blocking layer having a stripe-shaped groove parallel to the resonator direction in contact with the second conductivity type semiconductor layer;
  A dielectric is embedded on the resonator end face side in the groove, and a conductive oxide made of ITO is embedded inside the dielectric in the groove,
  The dielectric is ZrO. ₂ , SiO ₂ , Al ₂ O ₃ , Nb ₂ O ₃ TiO ₂ , Ta ₂ O ₅ Formed of a material selected from the group consisting of AlN and SiN,
  And a second current blocking layer having a striped second groove parallel to the resonator direction in contact with the first conductivity type layer, the second current blocking layer being located on the resonator end face side in the second groove. 2. A semiconductor laser device, wherein a second dielectric oxide is embedded, and a second conductive oxide layer is embedded inside the second dielectric in the second groove.

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