JP6682800B2 - Semiconductor laser device - Google Patents

Description

  The present disclosure relates to a semiconductor laser device.

In recent years, semiconductor laser devices have been used for various purposes. For example, a plurality of semiconductor laser elements are connected in series and used as a light source of a projector.
In such an application of the semiconductor laser device, when one semiconductor laser device is in a non-conductive state, even if the other semiconductor laser devices can be energized, the energization of all the semiconductor laser devices connected in series is stopped. , Will not function as a light source. Therefore, in order to secure the long-term reliability of the light source by the semiconductor laser element, it is necessary to avoid the interruption state of each semiconductor laser element.

  On the other hand, in order to make the FFP in the horizontal direction of the semiconductor laser element a single peak, to suppress the concentration of the current in a specific region to make the NFP uniform, and / or to suppress the generation of leakage current, etc. Measures for maintaining and improving the characteristics of the laser element have been studied (for example, Patent Documents 1 to 3).

JP-A-2000-196181 JP-A-2004-273955 JP, 2011-258883, A

  The present disclosure has been made in view of the above problems, and it is possible to avoid a non-conducting state of a semiconductor laser device, and for example, a semiconductor that can function efficiently even for the above-described application using a plurality of serial connections. An object is to provide a laser device.

The present disclosure includes the following inventions.
(1) A semiconductor laminated body having a ridge formed on its surface,
A first electrode layer disposed on the ridge in contact with the semiconductor laminated body and extending in the longitudinal direction;
A current injection blocking layer that covers at least a part of the upper surface from the side surface of the first electrode layer;
A second electrode layer disposed on the current injection blocking layer,
The current injection blocking layer contacts the first electrode layer in 18% to 80% of the contact area between the first electrode layer and the semiconductor stacked body,
The semiconductor laser device, wherein the second electrode layer is in contact with part of the first electrode layer.

(2) A semiconductor laminated body having a ridge formed on its surface,
A first electrode layer disposed on the ridge in contact with the semiconductor laminated body and extending in the longitudinal direction;
A current injection blocking layer covering a part of the first electrode layer,
A second electrode layer disposed on the current injection blocking layer,
The current injection blocking layer has, in plan view, a protrusion extending from both edges of the first electrode layer extending in the longitudinal direction toward the central region of the ridge or an island portion arranged on the central region of the ridge. Have
The semiconductor laser device, wherein the second electrode layer is in contact with part of the first electrode layer.

  According to the present disclosure, it is possible to provide a semiconductor laser device that can avoid a non-conducting state of the semiconductor laser device and can function efficiently even for the use by a plurality of serial connections described above.

1A is a schematic plan view showing an embodiment of a semiconductor laser device of the present invention, FIG. 1B is a sectional view taken along the line AA ′, and FIG. 1C is a line BB ′. It is a line sectional view. It is a partially expanded view of FIG. FIG. 2 is a schematic plan view of a state in which a current injection blocking layer and a second electrode layer are removed from FIG. It is a schematic plan view of the principal part which shows another embodiment of the semiconductor laser element of this invention. It is a schematic plan view of the principal part which shows another embodiment of the semiconductor laser element of this invention. It is a schematic plan view of the principal part which shows another embodiment of the semiconductor laser element of this invention. It is a schematic plan view of the principal part which shows another embodiment of the semiconductor laser element of this invention. It is a schematic plan view of the principal part which shows another embodiment of the semiconductor laser element of this invention. It is a schematic plan view which shows the comparative example of a semiconductor laser element. It is a schematic plan view which shows the comparative example of a semiconductor laser element. 5 is a graph showing evaluation of the semiconductor laser devices of Embodiments 1 to 4. 9 is a graph showing evaluation of the semiconductor laser devices of Embodiments 5 and 6.

  The inventor of the present application has conducted intensive research on the phenomenon in which a plurality of semiconductor laser elements connected in series as described above become disconnected, and it is found that a stepwise phenomenon occurs before the disconnection. I found it.

First, when a plurality of semiconductor laser elements are connected in series and the semiconductor laser elements are energized, the laser oscillation of one of the semiconductor laser elements is stopped after a long time, and a non-lighting state occurs. Even in such a non-lighting state, the other plurality of semiconductor laser devices connected in series still oscillate and maintain the lighting state. At this time, in the non-lighted semiconductor laser device, the pn junction is deteriorated, and a leak current is generated in a minute current region.
Further, when the semiconductor laser element in the non-lighting state is continuously energized, a local current concentration occurs at the leak portion, and the semiconductor laminated body including the pn junction is destroyed.
Then, when these semiconductor laser elements are further energized, in the semiconductor laser element in the non-lighting state, the physical destruction of the semiconductor laminated body including the pn junction progresses, and eventually this semiconductor laser element becomes in the non-conductive state. Becomes Due to this, energization of all the semiconductor laser elements connected in series is stopped, and the semiconductor laser elements do not function as a light source.

  On the other hand, in order to avoid such a disconnected state of all the semiconductor laser elements connected in series, in each semiconductor laser element, a region where the semiconductor laminated body including the pn junction is hard to be broken or is not broken is provided. It has been found effective to secure and increase such areas as much as possible. Then, even if the semiconductor laser element is in a non-lighting state, when the other semiconductor laser elements connected in series maintain the lighting state, a portion that is easily deteriorated and easily broken in the non-lighting semiconductor laser element, It is confirmed that the parts are the central part of the optical waveguide in the semiconductor laminate and both sides thereof (regions having high light density and / or high current density, such as the active layer and its vicinity or surface), and the parts are confirmed. The inventors have found that not directly injecting a current into the semiconductor device can effectively suppress the deterioration of the semiconductor laminated body including the pn junction and suppress physical destruction, and have completed the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings as appropriate. However, the light emitting device described below is for embodying the technical idea of the present invention, and the present invention is not limited to the following unless specified otherwise. In addition, the contents described in one embodiment and example can be applied to other embodiments and examples.
The size, positional relationship, and the like of the members shown in the drawings may be exaggerated for clarity of description.

  The semiconductor laser device according to the present embodiment mainly includes a semiconductor laminated body having a ridge formed on the surface thereof, a first electrode layer disposed on the ridge, and a current injection blocking disposed in contact with the first electrode layer. A layer and a second electrode layer disposed on the current injection blocking layer. Further, the semiconductor laser element has a third electrode layer arranged thereon. The third electrode layer may be arranged, for example, on the surface of the semiconductor laminated body on the side opposite to the surface on which the ridge is arranged, or by removing a part of the semiconductor laminated body, the same as the first electrode layer. It may be arranged on the surface side. For example, the first electrode layer and the second electrode layer are p electrodes, and the third electrode layer is an n electrode.

(Semiconductor laminate)
Generally, the semiconductor laminated body is preferably formed by laminating a first conductive type semiconductor layer, an active layer and a second conductive type semiconductor layer in this order. The type of these semiconductor layers is not particularly limited, and examples thereof include various semiconductors such as III-V group compound semiconductors. Specific examples thereof include nitride-based semiconductor materials such as In _X Al _Y Ga _1-XY N (0 ≦ X, 0 ≦ Y, X + Y ≦ 1), and AlN, GaN, InGaN, AlGaN, InGaAlN, and the like. Can be used. As the composition, film thickness, layer structure and the like of each layer, those known in the art can be used.

  In particular, the semiconductor laminated body preferably has a light guide layer in the first conductive type semiconductor layer (for example, n-type layer) and / or the second conductive type semiconductor layer (for example, p-type layer). It is preferable to use SCH (Separate Confinement Heterostructure) in which these light guide layers sandwich an active layer. 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 a structure different in composition and / or film thickness from each other.

The active layer may have either a multiple quantum well structure or a single quantum well structure. Well layer preferably has at least general formula In contain the _{In x Al y Ga 1-xy} N (0 <x ≦ 1,0 ≦ y <1,0 <x + y ≦ 1). For example, it is possible to emit light in a wavelength range of about 300 nm to 650 nm.

  The method for forming the semiconductor laminated body is not particularly limited, and MOVPE (Metal Organic Chemical Vapor Deposition), MOCVD (Metal Organic Chemical Vapor Deposition), HVPE (Hydride Vapor Deposition), MBE (Molecular Beam Epitaxy) Any method known as a method for growing a semiconductor that constitutes a semiconductor laminated body such as a nitride semiconductor may be used. In particular, MOCVD is preferable because it can be grown with good crystallinity under reduced pressure or atmospheric pressure.

  The semiconductor laminated body is usually formed on a substrate. The material of the substrate used here may be sapphire, silicon carbide, silicon, ZnSe, ZnO, GaAs, diamond, nitride semiconductor (GaN, AlN, etc.) or the like.

The thickness of the substrate is, for example, about 50 μm to 1 mm.
More preferably, the substrate is, for example, a nitride semiconductor substrate having an off angle of about 0.03 to 10 ° on the first main surface and / or the second main surface. The substrate may have a grid-like, stripe-like, or island-like unevenness on its surface. As the substrate, a substrate in which dislocation density and / or polarity are distributed almost uniformly can be used, and a substrate in which dislocation density is periodically distributed in a stripe pattern and / or regions having different polarities are distributed. A thing etc. can also be used.

In addition, different crystal growth planes may be distributed on one surface of the substrate. For example, (0001) plane, (000-1) plane, (10-10) plane, (11-20) plane, (10-14) plane, (10-15) plane, (11-24) plane, etc. Two or more crystal growth planes may be distributed. When GaN is used as the substrate, the (0001) plane is typically used as the crystal growth plane.
A buffer layer, an intermediate layer (for example, Al _x Ga _{1 -x} N (0 ≦ x ≦ 1), etc.) and the like are formed on the substrate before forming a semiconductor laminated body functioning as a semiconductor laser device. May be.

  The semiconductor laminated body has an optical waveguide region therein. The optical waveguide region constitutes a resonator together with a laser light emitting surface and a reflecting surface. Therefore, the semiconductor laminated body is formed in a quadrangle, preferably a rectangular shape in plan view.

(ridge)
A ridge is formed on the surface of the semiconductor stacked body, for example, the surface of the second conductivity type semiconductor layer. The ridge has a function of defining an optical waveguide region below the ridge and in the active layer (optionally including a light guide layer). For this reason, the ridges are arranged in a stripe shape so as to extend in the cavity direction of the semiconductor laser device. Hereinafter, the resonator direction may be referred to as the longitudinal direction.

The width of the ridge is about 1 to 100 μm. In the case of a multiple transverse mode semiconductor laser device, the thickness is preferably about 10 to 100 μm, more preferably 15 to 80 μm, still more preferably 20 to 70 μm.
In general, since a semiconductor laser device of multiple transverse mode has a wide optical waveguide region (so-called wide stripe), COD can be further suppressed by lowering the current density. Further, in the wide-stripe laser element, since the contact area with the electrode is increased, the voltage is reduced, and the voltage difference in the cavity length direction is reduced, so that current concentration is less likely to occur and rapid decrease in optical output is reduced. be able to. Therefore, in the case of a multiple transverse mode semiconductor laser device, not only the COD but also a rapid decrease in optical output is suppressed.

  The height of the ridge can be appropriately adjusted depending on the film thickness, material, etc. of the layer forming the second conductivity type semiconductor layer, and is, for example, 0.1 to 2 μm. The ridge is preferably set so that the length of the semiconductor laser device in the cavity extension direction is about 100 to 2000 μm. The ridges need not all have the same width in the extension direction of the resonator. The side surface of the ridge may be vertical or may be tapered with an angle of about 60 to 90 °. In other words, the edge distance on the ridge top surface may be smaller than the edge distance on the ridge base (that is, the ridge bottom surface).

  The ridge is preferably formed so as to be arranged perpendicular to the cavity surface. Accordingly, the resonator surface can be a suitable light emitting surface and a suitable light reflecting surface.

  The ridge can be formed by a method known in the art, for example, a method of forming a mask pattern on the semiconductor laminate and etching using the mask pattern.

(First electrode layer)
The first electrode layer is disposed on the ridge and is in ohmic contact with the semiconductor stacked body forming the ridge with a sufficiently low contact resistance value. The first electrode layer has a shape extending in the extending direction of the ridge, that is, the longitudinal direction. The first electrode layer may cover the side surface of the ridge as long as it is arranged on the ridge, but it is preferably arranged only between both edges of the ridge. In other words, a part of the outer edge of the first electrode layer may be arranged on the side surface of the ridge or a region other than the ridge, but it is preferable that the entire outer edge is arranged on the ridge. With such an arrangement, carriers can be restricted below the ridge, and light can be confined below the ridge.

  The first electrode layer does not have to extend to the emission surface and the reflection surface of the semiconductor laser device. That is, the first electrode layer may be separated from the emission surface and the reflection surface in plan view. The separation distance may be the same or different on the emission surface side and the reflection surface side. For example, it is preferable that the separation distance of the first electrode layer on the emission surface side is equal to the separation distance of the reflection surface side. Further, the edges of the first electrode layer on the emitting surface side and the reflecting surface side may be parallel to the emitting surface or the reflecting surface of the semiconductor laser element, or a part thereof may project toward the emitting surface or the reflecting surface. It may have a different shape.

  The first electrode layer is made of, for example, Au, Pt, Pd, Rh, Ni, W, Mo, Cr, Ti, Cu, Ag, Zn, Sn, In, Al, Ir, Rh, Ru, ITO, etc., or alloys thereof. It can be formed by a single layer film or a laminated film. Specifically, a laminated film in which Ni / Au, Ni / Au / Pt, Ni / Au / Pd, Rh / Pt / Au, Ni / Pt / Au, and the like are laminated from the semiconductor layer side is exemplified. The film thickness may be any of the film thicknesses of films used in the art. For example, the film thickness of the first electrode layer is preferably 5 nm to 2 μm, more preferably 50 to 500 nm, further preferably 100 to 300 nm.

(Current injection blocking layer)
The current injection blocking layer covers at least a part of the first electrode layer.
In one embodiment, the current injection blocking layer covers a part of the upper surface of the first electrode layer. In another embodiment, the current injection blocking layer covers at least a part of the upper surface from the side surface (for example, the side surface extending in the longitudinal direction) of the first electrode layer.
It is preferable that the current injection blocking layer further covers the side surface of the ridge from the side surface extending in the longitudinal direction of the first electrode layer, and covers the surface of the semiconductor stacked body on both sides of the ridge. By providing in this way, it is possible to insulate the semiconductor laminated body from the second electrode layer which will be formed later as a buried film filling both sides of the ridge. In this case, the current injection blocking layer is arranged on the surface of the semiconductor laminated body so that the second electrode layer described later does not come into direct contact with the surface. An insulating film that functions as a buried film may be provided as a film different from the current injection blocking layer, but it is preferable to dispose the current injection blocking layer outside the ridge so as to function as a buried film. This can reduce the number of steps. Moreover, the formation area of the current injection blocking layer is increased, and peeling can be prevented.

  In other words, the current injection blocking layer may have a shape that covers substantially the entire surface of the semiconductor laminated body including the ridge and has an opening that exposes a part of the first electrode layer on the ridge. This opening serves as a contact portion with the second electrode layer described later and serves as a current injection region.

  It is preferable that the current injection blocking layer is arranged on the ridge so as to surround the outer periphery of the first electrode layer with a predetermined width and expose the first electrode layer in other portions. The outer circumference here may be a part or the whole. In other words, the outer circumference may be in the vicinity of only a part or the whole of both longitudinal edges or only in the vicinity of both longitudinal edges and both lateral edges. The predetermined width is not particularly limited and may be about 0.1 to 5 μm, preferably about 0.5 to 3 μm. The width may be different over the entire circumference, but is preferably the same. When the current injection blocking layer has a protrusion described later, it is preferable that the portion excluding the protrusion has such a numerical range.

  In one embodiment, the current injection blocking layer is 18% to 80% of the contact area between the first electrode layer and the semiconductor stacked body (the same as the plane area of the first electrode layer in Embodiment 1 or the like described later). Is preferably contacted with. In other words, the current injection blocking layer is preferably disposed on 18% to 80% of the plane area of the first electrode layer disposed on the ridge, more preferably 18% to 60%, -50% is more preferable. The plane area of the first electrode layer refers to the area of the first electrode layer in plan view (when viewed from the upper surface side of the first electrode layer). When the first electrode layer extends to the outside of the ridge through an insulating buried film or the like, the current injection is blocked at the above ratio based on the contact area between the first electrode layer and the semiconductor laminated body. It is preferred that the layer is arranged on the first electrode layer.

  In another embodiment, the current injection blocking layer extends from both edges of the first electrode layer toward the central region of the ridge in plan view, as will be described later, regardless of the size of the contact area with the first electrode layer. It is preferable to have an extending portion and / or an island portion arranged on the central region of the ridge. Both edges of the first electrode layer are outer edges extending in the longitudinal direction on both sides of the first electrode layer. That is, the outer edge along the side surface of the ridge. The central region refers to a region inside both edges and side faces.

  The shape of the current injection blocking layer that covers the first electrode layer is not particularly limited, but is a region that is easily destroyed in the semiconductor laminated body including the pn junction as described above (hereinafter, may be referred to as a destroyed region). In order to prevent the current from being injected into the first electrode layer existing above, it is preferable to have a shape that covers the area above the destroyed area. Here, since the destroyed region is considered to be a region having a high light density, a region having a high current density, and the like, examples thereof include a central region of the optical waveguide and regions near both ends of the ridge base. Therefore, by covering the regions capable of blocking the current injection into these regions, that is, the portions of the first electrode layer arranged above these regions with the current injection blocking layer, the current flowing into these regions can be prevented. Can be reduced. As a result, it is possible to reduce the light density and / or the current density in the destroyed region and prevent the non-conducting state.

The shape of the current injection blocking layer is, for example, a plan view,
(A) A shape that covers the side surfaces extending in the longitudinal direction of the first electrode layer and covers the vicinity of both edges extending in the longitudinal direction of the first electrode layer,
(B) A shape extending from both edges extending in the longitudinal direction of the first electrode layer toward the central region of the ridge (hereinafter, may be referred to as a protrusion),
(C) A shape (hereinafter sometimes referred to as an island portion) arranged on the central region of the ridge, and the like.
The current injection blocking layer may have only one of these shapes, or may have a combination of two or more shapes.

  Here, the vicinity of both edges in (a) depends on the width of the ridge, the magnitude of the current and / or voltage applied to the semiconductor laser element, and the like, but, for example, from the edge of the first electrode layer to the first electrode. The width is about 2 to 30% of the width of the layer, and the width is preferably about 5 to 20%. When both edges are provided with the same width, the area occupied by the current injection blocking layer on the first electrode layer is doubled. The shape that covers the vicinity of both edges may be a continuous shape over the entire length of the first electrode layer in the longitudinal direction, or may be a divided shape. Therefore, the shape may cover only a part of the first electrode layer in the longitudinal direction.

  The term “extending toward the central region of the ridge” in (b) means, for example, a width of about 5 to 50% of the width of the first electrode layer from the edge of the first electrode layer, and a width of about 8 to 50%. Is preferred. When extending from both edges with the same width, the area occupied by the current injection blocking layer on the first electrode layer is double that. The projecting portion is provided in a shape extending toward the central region of the ridge rather than a portion provided in the vicinity of both edges of (a) with a substantially constant width. The protrusion may extend from one edge in the longitudinal direction to the other edge in the central region of the ridge, with the protrusions extending from both edges connected to each other. The protruding portion may have a continuous shape over the entire length of the first electrode layer in the longitudinal direction, or may have a divided shape. Therefore, the shape may cover only a part of the first electrode layer in the longitudinal direction. As for the length of the protrusion (the length along the longitudinal direction of the first electrode layer), for example, when one is extended from both sides, the length of the protrusion on one side is the length of the first electrode layer. It is preferable that the length is about 70 to 95%, and in the case of extending a plurality of pieces, the total length on one side is about 30 to 70% of the length of the first electrode layer. It is preferable. When the first electrode layer has the electrode protrusion, it is preferable not to provide the protrusion extending from the side surface of the first electrode layer, and it is preferable to provide only the protrusion extending from both edges of the first electrode layer.

Arranged on the central region of the ridge in (c) means that there is a so-called island-shaped portion that is separated from the portion of the current injection blocking layer that covers the side surface of the first electrode layer. To do. The width of the island portion is, for example, about 5 to 90% of the width of the first electrode layer, and is preferably about 40 to 80%. The number of islands may be singular or plural. In the case of a plurality of electrodes, they can be arranged linearly along the longitudinal direction of the first electrode layer. The shape may be continuous over the entire length of the first electrode layer in the longitudinal direction, or may be a divided shape. Therefore, the shape may cover only a part of the first electrode layer in the longitudinal direction. The length of the island portion (the length along the longitudinal direction of the first electrode layer) is preferably about 70 to 95% of the length of the first electrode layer in the case of a singular part, and the total length in the case of a plurality of parts. However, the length is preferably about 30 to 70% of the length of the first electrode layer.
When a plurality of protrusions and / or islands are provided, it is preferable to disperse them substantially evenly in the longitudinal direction of the first electrode layer. When the first electrode layer has the electrode protrusions as in Embodiment 1 described later, the arrangement interval may be changed only in the portion closest to the electrode protrusions. The number of protrusions and / or islands may be 10 or more, or 50 or more.

As a specific shape of the current injection blocking layer, for example,
(i) a shape in which a plurality of protruding portions of the current injection blocking layer are divided and arranged in the longitudinal direction,
(ii) A shape in which the island portion of the current injection blocking layer is arranged to extend in the longitudinal direction in the central region of the ridge in plan view.
(iii) A plurality of protruding portions of the current injection blocking layer are arranged in the longitudinal direction so as to be divided, and the island portion is divided in the longitudinal direction between the central region of the ridge and the protruding portion at one edge of the first electrode layer. And a plurality of shapes arranged,
(iv) A shape in which the protruding portion of the current injection blocking layer extends from one edge to the other edge of the first electrode layer in a plan view and is divided into a plurality in the longitudinal direction, and the like, may be mentioned.

  The current injection blocking layer is preferably made of an insulating material. Further, the current injection blocking layer is preferably formed of a material having a refractive index lower than that of the semiconductor laminated body in order to easily confine light in the ridge. The current injection blocking layer can be formed by, for example, a single layer or a multilayer including an oxide, a nitride, or an oxynitride of Si, Zr, Al, or Ta. The thickness is not particularly limited as long as it is a thickness that can reduce or prevent current injection into the semiconductor laminated body, and examples thereof include about 0.01 to 1 μm.

  The current injection blocking layer can be formed by forming a film on a desired portion and patterning it into a desired shape by a method known in the art.

(Second electrode layer)
The second electrode layer is what is ultimately connected to the outside as a so-called pad electrode, and is arranged on the first electrode layer via the current injection blocking layer. The second electrode layer is in contact with the first electrode layer in the opening of the current injection blocking layer. That is, the current injection blocking layer partially exists between the first electrode layer and the second electrode layer. The second electrode layer has an area of 20 to 82% of the contact area between the first electrode layer and the first electrode layer and the semiconductor laminated body (the same as the plane area of the first electrode layer in Embodiment 1 described later). More preferably, it is arranged in direct contact with an area of 40 to 82%, particularly an area of 50 to 82%. With such an arrangement, as described above, when the current is injected through the second electrode layer by the partial contact with the first electrode layer, the current injection density of the first electrode layer is blocked. It can be relaxed where the layer is present. As a result, it is possible to reduce the light density and the current density in the semiconductor laminated body corresponding to the above-mentioned destruction target region, alleviate the physical destruction of these, and avoid the interruption state. On the other hand, the presence of the first electrode layer below the current injection blocking layer makes it possible to suppress an extreme decrease in power conversion efficiency due to the limitation of the current injection region.

  The second electrode layer may be arranged only on the first electrode layer, or a current injection blocking layer or another insulating film may be formed on the semiconductor laminated body arranged on both sides of the ridge from the first electrode layer. It may be arranged through. The second electrode layer may be separated from the emission surface and the reflection surface in plan view. The separation distance may be the same or different on the emission surface side and the reflection surface side. For example, the edges on the emission surface side and the reflection surface side of the second electrode layer are arranged inside (the side far from the emission surface and the reflection surface) with respect to the edges on the emission surface side and the reflection surface side of the first electrode layer. Although it may be provided, it is preferably arranged on the outside (the side close to the emission surface and the reflection surface). The edges on the emission surface side and the reflection surface side of the second electrode layer may have a shape projecting toward the emission surface or the reflection surface of the semiconductor laser element, but the edges should be parallel to the emission surface or the reflection surface. Is preferred.

  The second electrode layer can be formed, for example, by selecting the same material as the material forming the first electrode layer. For example, a laminated film made of a metal such as Ni, Ti, Au, Pt, Pd, W or Rh is preferable. Specifically, a film formed in the order of W / Pd / Au, Ni / Ti / Au, Ni / Pd / Au, and Ni / Pd / Au / Pt / Au from the semiconductor laminated body side can be mentioned. The outermost surface of the second electrode layer preferably contains Au. The thickness of the second electrode layer as the pad electrode is not particularly limited, but the thickness of the final layer of Au is preferably about 100 nm or more. For example, the total thickness of the second electrode layer is more preferably 0.3 to 3 μm, further preferably 0.5 to 2 μm.

(Third electrode layer)
The third electrode layer may be arranged on the surface of the semiconductor laminated body opposite to the surface on which the ridge is arranged in the semiconductor laser element, or a part of the semiconductor laminated body may be removed to form the first electrode. It may be arranged on the same surface side as. When a conductive material is used for the substrate, the third electrode layer can be provided on the lower surface of the substrate (the surface opposite to the surface provided with the semiconductor laminate).
The third electrode layer can be formed by selecting from the same material as the first electrode layer or the second electrode layer.

(Production method)
The above-mentioned semiconductor laser device can be formed by using a method known in the art. Further, an additional protective film and / or an insulating film, an electrode layer, etc. may be optionally formed.
The semiconductor laser device may be a resonator surface formed by a plane selected from the group consisting of M plane (1-100), A plane (11-20), C plane (0001) or R plane (1-102). Are preferably formed. In the case of a hexagonal nitride semiconductor laser device, the M plane is typically used as the cavity facet.

(Embodiment 1)
As shown in FIGS. 1 and 3, in the semiconductor laser device 10 of the first embodiment, a semiconductor laminated body 12 is laminated on a substrate 11, and a ridge 13 is formed on the surface of the semiconductor laminated body 12. ,It is configured. FIG. 3 is a schematic plan view showing a state where only the first electrode layer 14 is formed on the ridge 13, that is, a state where the current injection blocking layer 15 and the second electrode layer 16 are removed from FIG. By forming the current injection blocking layer 15 and the second electrode layer 16 thereon, the semiconductor laser device 10 shown in FIG. 1A is obtained.
The semiconductor laser device 10 has a rectangular shape of 1200 μm × 150 μm in a plan view, and the surface obtained by cleaving at the M surface is a resonator surface.
As described above, in the first embodiment, specific examples of dimensions and materials will be described, but this is an example and the present invention is not limited thereto. The same applies to the following embodiments.

The substrate 11 is made of n-type GaN.
The semiconductor stacked body 12 is formed on the substrate 11.
Si-doped GaN layer (film thickness 10 nm),
Si-doped Al _0.02 Ga _0.98 N layer (film thickness 1.6 μm),
Si-doped GaN layer (film thickness 10 nm),
Si-doped In _0.05 Ga _0.95 N layer (film thickness 0.15 μm),
Si-doped GaN layer (film thickness 10 nm),
A lower clad layer made of Si-doped Al _0.07 Ga _0.93 N (film thickness 0.9 μm),
A lower guide layer made of Si-doped GaN (film thickness 0.3 μm),
MQW active layer,
Mg-doped Al _0.12 Ga _0.88 N layer (film thickness 1.5 nm),
Mg-doped Al _0.16 Ga _0.84 N layer (film thickness 8.5 nm),
An upper guide layer made of undoped Al _0.04 Ga _0.96 N (film thickness 0.15 μm) and Mg-doped Al _0.04 Ga _0.96 N (film thickness 0.15 μm),
An upper contact layer made of Mg-doped GaN (film thickness 15 nm) is laminated in this order.

The MQW active layer includes a barrier layer and a well layer, and sequentially from the substrate 11 side,
An undoped In _0.03 Ga _0.97 N layer (film thickness 250 nm),
A Si-doped GaN layer (film thickness 10 nm),
Undoped In _0.15 Ga _0.85 N layer (thickness 3 nm) and undoped GaN (thickness 3 nm),
An undoped In _0.15 Ga _0.85 N layer (thickness 3 nm),
And a composition gradient layer (film thickness 250 nm) that changes from undoped In _0.05 Ga _0.95 N to GaN.

The ridge 13 has a width of 50 μm and is formed in a stripe shape. The depth was the depth at which the upper guide layer was exposed. The ridge 13 can be formed by, for example, photolithography and RIE etching.
The side surface of the semiconductor laser device 10 is provided with a step reaching the semiconductor stacked body 12 (for example, an n-type semiconductor layer) (see FIG. 1C). However, a step reaching the substrate 11 may be provided, or no step may be provided.

  As shown in FIG. 2, a first electrode layer 14 (p electrode) made of ITO is formed on the ridge 13 with an electrode width g (for example, 47 μm) slightly smaller than the width h of the ridge 13 and a film thickness of 200 nm. Has been formed. The first electrode layer 14 is formed to extend in the longitudinal direction. The first electrode layer 14 has an electrode projecting portion 14a extending toward the emission surface and the reflection surface at the center of the ends on the emission surface side and the reflection surface side, and is arranged separately from the emission surface and the reflection surface, respectively. ing. The width f of the electrode protrusion 14a is 25 μm, the length i is 30 μm, and the total length of the first electrode layer is 1166 μm.

A current injection blocking layer 15 made of SiO ₂ is arranged on the first electrode layer 14. The current injection blocking layer 15 has a thickness of 200 nm. In other words, the current injection blocking layer 15 is formed on substantially the entire surface of the semiconductor laminated body 12 including the ridge 13, has an opening on the first electrode layer 14, and the inside is the current injection region 18. .

The current injection blocking layer 15 is a top surface near the edge of the first electrode layer 14 from the side surface of the first electrode layer 14 (the distance e from the edge of the first electrode layer 14 is 1.5 μm, the edge of the ridge 13 is The distance d from 3 to 3 μm) is further covered, and further, the entire upper surface of the semiconductor laminated body 12 and the side surface of the ridge 13 are continuously covered. The outer edge of the current injection blocking layer 15 coincides with the outer edge of the semiconductor stacked body 12.
The current injection blocking layer 15 has a projecting portion 15 a extending from both edges extending in the longitudinal direction of the first electrode layer toward the central region of the ridge 13 in a plan view. A plurality of protrusions are divided and arranged in the longitudinal direction. The protrusion 15 a protrudes from the end of the upper surface of the current injection blocking layer 15 that covers the vicinity of the edge of the first electrode layer 14 with a protrusion width c (6 μm). Therefore, in the protruding portion 15 a, the current injection blocking layer 15 covers the ridge 13 and the first electrode layer 14 with a width of 9 μm from the edge of the ridge 13.

The protrusions 15a of the current injection blocking layer 15 have a length b of about 10 μm with an interval a of about 10 μm. However, at the end in the longitudinal direction, the distance a ′ is 8 μm and the length b ′ is 8.5 μm.
The current injection blocking layer 15 is in contact with the first electrode layer 14 in 19.1% of the plane area of the first electrode layer 14.

The second electrode layer 16 is disposed on the current injection blocking layer 15. The second electrode layer 16 is formed so as to cover the upper surface of the semiconductor stacked body 12, the side surface of the ridge 13, and the upper surface of the ridge 13, and is in contact with part of the first electrode layer 14. Therefore, the first electrode layer 14 and the second electrode layer 16 are in contact with each other in the current injection region 18, so that a current is injected from the second electrode layer 16 to the semiconductor stacked body 12 via the first electrode layer 14. can do.
The second electrode layer 16 is, for example, from the semiconductor laminated body 12 side, Ni (film thickness 8 nm) / Pd (film thickness 200 nm) / Au (film thickness 400 nm) / Pt (film thickness 200 nm) / Au (film thickness 700 nm). It is formed of a laminated film of. The second electrode layer 16 is disposed on the ridge 13 up to the vicinity of the short-side end (resonator surface) of the semiconductor laminated body 12, and slightly inside the long-side edge of the semiconductor laminated body 12. The edge portion of the second electrode layer 16 is disposed at. Further, the four edges of the semiconductor laser device 10 are arranged so that their edges are recessed inward.

  The substrate 11 has a thickness of about 80 μm. A third electrode layer 17 made of Ti (film thickness 6 nm) / Pt (film thickness 200 nm) / Au (film thickness 300 nm) is formed on the back surface of the substrate 11 from the substrate 11 side.

In the semiconductor laser device 10, Al ₂ O ₃ is formed on the emitting surface of the resonator as the emitting side mirror with a film thickness of 137 nm, and as the reflecting surface mirror, Al ₂ O ₃ (film is formed on the reflecting surface of the resonator. Thickness 137 nm) / Ta ₂ O ₅ (film thickness 52 nm) is formed, and SiO ₂ (film thickness 76 nm) / Ta ₂ O ₅ (film thickness 52 nm) in total of 6 pairs is formed on top of this, and SiO 2 is further formed thereon. ₂ (film thickness 153 nm) is formed.

  Such a semiconductor laser device 10 is usually mounted facedown on a supporting member using a connecting member (AuSn eutectic or the like). The support member has a base made of SiC and a conductive layer made of Ti / Pt / Au / Pt (Ti is on the base side) formed thereon.

As described above, in the semiconductor laser device of this embodiment, current is injected into the semiconductor laminated body by the current injection region 18 having a peculiar shape. It is possible to effectively reduce the occurrence of leakage current in the minute current region by reducing As a result, even when the semiconductor laser element is further energized, the local current concentration generated at the leak location can be mitigated, and the destruction of the semiconductor laminated body including the pn junction can be suppressed. As a result, it is possible to prevent or avoid physical destruction of the semiconductor laminated body including the pn junction portion, and avoid interruption of the semiconductor laser device. In particular, when a plurality of semiconductor laser elements are connected in series, it is possible to avoid the non-conducting state of each semiconductor laser element, so that all the semiconductor laser elements are prevented from being non-conducting.
Further, the above-described structure for avoiding the non-conducting state can supply sufficient electric power without adversely affecting the oscillation of the semiconductor laser element, and as shown in the evaluation described later, a decrease in power conversion efficiency can be prevented. Suppression can be realized.

(Embodiment 2)
The semiconductor laser device according to the second embodiment has a structure in which a semiconductor laminated body 12 is laminated on a substrate 11, and a ridge 13 is formed on the surface of the semiconductor laminated body 12 as shown in FIG. ing. A first electrode layer 24 having an electrode protrusion 24 a is formed on the ridge 13.

A current injection blocking layer 25 is arranged on the first electrode layer 24.
The current injection blocking layer 25 covers the side surface of the first electrode layer 24 from the side surface of the first electrode layer 24 to the upper surface in the vicinity of the edge, and further connects the entire upper surface of the semiconductor stacked body 12 and the side surface of the ridge 13 continuously. Then covered. The outer edge of the current injection blocking layer 25 coincides with the outer edge of the semiconductor laminated body 12 as in the semiconductor laser device 10 of the first embodiment.
The current injection blocking layer 25 further has an island portion 25b arranged on the central region of the ridge 13 in plan view.

As shown in FIG. 4, the island portion 25b of the current injection blocking layer 25 has a width j of 10 μm and a longitudinal length of 1087 μm.
The current injection blocking layer 25 is separated from the both ends that cover the upper surface near the edge extending in the longitudinal direction of the first electrode layer 24 by a distance jj of 17 μm.
The current injection blocking layer 25 is in contact with the first electrode layer 24 in 27.1% of the plane area of the first electrode layer 24.

  Except for the shape of the current injection blocking layer 25 described above, it has substantially the same configuration as the semiconductor laser device 10 of the first embodiment.

(Embodiment 3)
In the semiconductor laser device of the third embodiment, as shown in FIG. 5, the first electrode layer 34 having the electrode protrusions 34a is formed on the ridge 13. Further, the current injection blocking layer 35 is arranged on the first electrode layer 34.
The current injection blocking layer 35 covers the upper surface near the edge of the first electrode layer 34 from the side surface of the first electrode layer 34, and further, the entire upper surface of the semiconductor stacked body 12 and the side surface of the ridge 13 are continuous. Then covered. The outer edge of the current injection blocking layer 35 coincides with the outer edge of the semiconductor stacked body 12 as in the semiconductor laser device 10 of the first embodiment.
The current injection blocking layer 35 further has an island portion 35b arranged on the central region of the ridge 13 in plan view.

As shown in FIG. 5, the island portion 35b of the current injection blocking layer 35 has a width k of 18 μm and a length in the longitudinal direction of 1087 μm.
The current injection blocking layer 35 is separated from the both ends covering the upper surface near the edge extending in the longitudinal direction of the first electrode layer 34 by a distance kk of 13 μm, respectively.
The current injection blocking layer 35 is in contact with the first electrode layer 34 in 47.4% of the plane area of the first electrode layer 34.

  Except for the shape of the current injection blocking layer 35 described above, it has substantially the same configuration as the semiconductor laser device 10 of the first embodiment.

(Embodiment 4)
In the semiconductor laser device according to the fourth embodiment, as shown in FIG. 6, the first electrode layer 44 having the electrode protruding portion 44a is formed on the ridge 13. Further, the current injection blocking layer 45 is arranged on the first electrode layer 44.
The current injection blocking layer 45 covers the upper surface near the edge of the first electrode layer 44 from the side surface extending in the longitudinal direction of the first electrode layer 44, and further covers the entire upper surface of the semiconductor stacked body 12 and the ridge 13. The side surfaces are continuously covered.
The current injection blocking layer 45 has a projecting portion 45 a extending from both edges extending in the longitudinal direction of the first electrode layer 44 toward the central region of the ridge 13 in a plan view. A plurality of protrusions 45a are arranged in the longitudinal direction so as to be divided.

Further, the current injection blocking layer 45 has an island portion 45b in the central region of the ridge 13 in a plan view, and the plurality of island portions 45b are arranged in the longitudinal direction.
The island portion 45b is arranged between the protrusions 45a in the longitudinal direction, and is arranged in the central portion of the current injection blocking layer in the lateral direction. Thus, when both the island portion 45b and the protruding portion 45a are provided, the island portion 45b can be arranged between the protruding portions 45a.
The spacing 1 between the island portions 45b is 10 μm, the length n of the island portion 45b is 10 μm, and the width m of the island portion 45b is 20 μm.
The current injection blocking layer 45 is in contact with the first electrode layer 44 in 39.3% of the plane area of the first electrode layer 44.

  Except for the shape of the current injection blocking layer 45 described above, it has substantially the same configuration as the semiconductor laser device 10 of the first embodiment.

(Embodiment 5)
The semiconductor laser device of the fifth embodiment has a structure in which a semiconductor laminated body 12 is laminated on a substrate 11, and a ridge 53 is formed on the surface of the semiconductor laminated body 12 as shown in FIG. ing. A first electrode layer 54 is formed on the ridge 53.
The ridge 53 has a width of 35 μm and is formed in a stripe shape.

  The first electrode layer 54 (p electrode) is formed on the ridge 53 with a width slightly narrower than that of the ridge 53. The first electrode layer 54 has an electrode protrusion 54a that protrudes in the longitudinal direction. The electrode protrusion 54a has a length of 30 μm and a width of 15 μm.

A current injection blocking layer 55 is arranged on the first electrode layer 54.
The current injection blocking layer 55 covers the side surface of the first electrode layer 54 from the side surface of the first electrode layer 54 to the upper surface in the vicinity of the edge, and further connects the entire upper surface of the semiconductor stacked body 12 and the side surface of the ridge 53 to each other. Then covered.
The current injection blocking layer 55 has, in a plan view, a protruding portion 55a having a shape that extends from one edge extending in the longitudinal direction of the first electrode layer 54 to the other edge and is connected. The plurality of protrusions 55a are arranged in the longitudinal direction so as to be divided.
The width of the protrusion 55a is 29 μm from one edge extending in the longitudinal direction of the first electrode layer 54 to the other edge. The width u ′ of the current injection region here is 17 μm. The interval t in the longitudinal direction between the protrusions 55a is 16 μm, and the length s thereof is 16 μm. However, the interval r of the portion closest to the electrode protrusion 54a is 15.5 μm.
In the portion of the first electrode layer 54 corresponding to the electrode protrusion 54a, the interval p between the protrusions 55a is 15 μm, the length q thereof is 15 μm, and the width u of the current injection region 58 is 12 μm. The projecting portion 55a on the most end side is arranged at the connecting portion with the internal region of the electrode projecting portion 54a.
Such a current injection blocking layer 55 is in contact with the first electrode layer 54 in 72.7% of the plane area of the first electrode layer 54.

  Except for the configuration described above, it has substantially the same configuration as the semiconductor laser device 10 of the first embodiment.

(Embodiment 6)
In the semiconductor laser device of this embodiment, as shown in FIG. 8, the current injection blocking layer 65 covers a part of the upper surface of the first electrode layer 64 from the side surface of the first electrode layer 64, and further, the semiconductor lamination is performed. The entire upper surface of the body 12 and the side surfaces of the ridge 53 are continuously covered.
The current injection blocking layer 65 has, in a plan view, a protruding portion 65a having a shape that extends from one edge extending in the longitudinal direction of the first electrode layer 64 to the other edge and is connected. The plurality of protruding portions 65a are arranged in a divided manner in the longitudinal direction.
The width of the protrusion 65a is 29 μm from one edge extending in the longitudinal direction of the first electrode layer 64 to the other edge. The width v ′ of the current injection region 68 here is 29 μm.
The width v of the current injection region 68 is 12 μm in the portion of the first electrode layer 64 corresponding to the electrode protrusion 64 a.
The current injection blocking layer 65 is in contact with the first electrode layer 64 at 54.1% of the plane area of the first electrode layer 64.

  Except for the configuration described above, it has substantially the same configuration as the semiconductor laser device of the first and fifth embodiments.

(Evaluation)
In order to evaluate the performance of the semiconductor laser devices of Embodiments 1 to 6, first, as comparative examples, the semiconductor laser devices of Comparative Example 1 and Comparative Example 2 shown in FIGS. 9A and 9B were prepared.
In the semiconductor laser device of Comparative Example 1, as shown in FIG. 9A, the protrusion in the current injection blocking layer was not provided on the first electrode layer 14 on the ridge 13 (width 50 μm), and the longitudinal direction thereof was straight. The semiconductor laser device 10 has the same configuration as the semiconductor laser device 10 of the first embodiment except that the current injection region 8a having a width of 44 μm is used. The width of the current injection region 8a in the electrode protrusion is 22 μm. The current injection region 8a occupies 6.8% of the plane area of the first electrode layer 14.
In the semiconductor laser device of Comparative Example 2, as shown in FIG. 9B, the protrusion in the current injection blocking layer was not provided on the first electrode layer 14 on the ridge 13a (width 35 μm), and the longitudinal direction thereof was straight. The semiconductor laser device 10 has the same configuration as the semiconductor laser device 10 of the fifth embodiment except that the current injection region 8a having a width of 29 μm is used. The width of the current injection region 8a in the electrode protrusion is 12 μm. The current injection region 8a occupies 9.4% of the plane area of the first electrode layer 14.

The power conversion efficiency when a current of 3.0 A is applied to each semiconductor laser element by CW drive (continuous drive) is shown in FIGS. 10 (b), (e), (h), (k), and FIG. Shown in (b) and (e). These figures are graphs showing the normal probability distributions of the power conversion efficiencies of a plurality of semiconductor laser devices obtained from one wafer. In these figures, each data is plotted with the horizontal axis as cumulative probability. The gray circles are the results of the semiconductor laser devices of Comparative Examples 1 and 2, and the black triangles are the results of the semiconductor laser devices of Embodiments 1 to 6.
10 (a), (d), (g), (j), FIG. 11 (a), and (d) schematically show the current injection regions of the first to sixth embodiments. 10 (b), (e), (h), (k), and FIG. 11 (b), (e).

  10 (b), (e), (h), (k), and FIGS. 11 (b), (e), the values at the cumulative probability of 50%, that is, the median values are compared, the first to fourth embodiments are compared. The reduction rates of the power conversion efficiency of the semiconductor laser device of Example 1 with respect to the semiconductor laser device of Comparative Example 1 were 0.2%, 0.2%, 0.8%, and 0.4%, respectively. It was confirmed that the rate of decrease in each case was within 1%. In particular, the semiconductor laser devices of Embodiments 1, 2, and 4 in which the current injection blocking layer is arranged on the first electrode layer in a proper position ensure substantially the same power conversion efficiency as in the case where the current injection blocking layer is not arranged. It was confirmed that it was done.

Comparing the median values in these figures, the reduction rates of the power conversion efficiencies of the semiconductor laser devices of Embodiments 5 and 6 with respect to the semiconductor laser device of Comparative Example 2 are 1.7% and 0.5%, respectively. It was Although the rate of decrease is slightly higher than in the first, second, and fourth embodiments, it was confirmed that the decrease in power conversion efficiency due to the provision of the current injection blocking layers 55 and 65 was suppressed in all cases.
The values of Comparative Example 1 are slightly different between FIG. 10B and FIGS. 10E, 10H, and 10K, which are different from those of Comparative Example 1 of FIG. 10 (e), (h), and (k) of Comparative Example 1 and Examples 2 to 4 were manufactured in different lots. The materials and the dimensions are the same in all Comparative Examples 1.

Voltages are continuously applied until each semiconductor laser element becomes unlit, and the result of continuously applying the voltage after unlit is shown in FIGS. 10 (c), (f), (i) for each elapsed time from unlit. ), (L) and FIGS. 11 (c) and 11 (f). The time of no lighting is 0 hours, and the vertical axis is a value obtained by dividing the voltage value at each time by the voltage value of 0 hours and standardizing. The broken line is the result of the semiconductor laser device of Comparative Example 1, and the solid line is the result of the semiconductor laser devices of Embodiments 1 to 6.
10 (a), (d), (g), (j), FIG. 11 (a), and (d) schematically show the current injection regions of the first to sixth embodiments. 10 (c), (f), (i), (l), and FIG. 11 (c), (f). In these graphs, only the semiconductor laser device of Comparative Example 1 was compared.

As shown in FIGS. 10 (c), (f), (i), (l), and FIGS. 11 (c) and (f), one of the semiconductor laser devices of Comparative Example 1 first had a voltage after 180 hours had elapsed. The value became zero, and by 750 hours, all four had a voltage value of zero. The state in which the voltage value is zero here indicates a state in which stable voltage characteristics cannot be maintained and energization is stopped. If a voltage is continuously applied to such a semiconductor laser device, a physical breakage occurs, and a current is not flowed into the semiconductor laser device. On the other hand, when a voltage was continuously applied to a plurality of semiconductor laser devices of Embodiments 1 to 6, the voltage did not become zero even after 800 hours, and the voltage could be continuously applied. The semiconductor laser devices of Embodiments 1 to 4 continued to apply the voltage up to 1000 hours, and the semiconductor laser devices of Embodiments 5 and 6 continued to apply the voltage up to 900 hours, but the voltage did not reach zero in either case.
From these results, unlike the semiconductor laser device of Comparative Example 1, none of the semiconductor laser devices of the present embodiment has a voltage value of zero over 800 hours or longer, and the voltage is continuously applied to the laser device itself. It was confirmed that it was done. That is, it was confirmed that the semiconductor laser device of the present embodiment does not become in a non-conductive state even after 800 hours.

  The semiconductor laser device of the present invention can be applied not only to the light source of the projector but also to laser devices used in various light sources.

10 semiconductor laser element 11 substrate 12 semiconductor laminated body 13, 53 ridge 14, 24, 34, 44, 54, 64 first electrode layer 14a, 24a, 34a, 44a, 54a, 64a electrode protruding portion 15, 25, 35, 45 , 55, 65 Current injection blocking layer 15a, 55a, 65a Projection portions 25b, 35b, 45b Island portion 16 Second electrode layer 17 Third electrode layer 18 Current injection region a, a ', t, r, p Current injection blocking layer B, b ′, s, q Length of protrusion of current injection blocking layer c Width of protrusion of current injection blocking layer d Distance from edge of ridge to edge of current injection blocking layer e Distance from edge of first electrode layer to edge of current injection blocking layer f Width of protrusion of first electrode layer g Electrode width of first electrode layer h Width of ridge i of protrusion of first electrode layer Length j, k, u, u'v, v'island Width Length of n island interval m islands of l island portion

Claims (10)

A semiconductor laminated body having a ridge formed on the surface;
A first electrode layer disposed on the ridge in contact with the semiconductor laminated body and extending in the longitudinal direction;
A current injection blocking layer that covers at least a part of the upper surface from the side surface of the first electrode layer;
A second electrode layer disposed on the current injection blocking layer,
The second electrode layer contacts a portion of the first electrode layer,
The current injection blocking layer extends from both edges of the first electrode layer extending in the longitudinal direction toward the central region of the ridge and is not connected from one edge to the other edge of the first electrode layer. Has a protrusion,
The semiconductor laser device according to claim 1, wherein the plurality of protrusions are arranged so as to be divided in a longitudinal direction of the first electrode layer in a plan view.   The semiconductor laser device according to claim 1, wherein the current injection blocking layer has an island portion arranged on a central region of the ridge in a plan view.   The semiconductor laser device according to claim 2, wherein the island portion of the current injection blocking layer is arranged in a shape extending in the longitudinal direction in the central region of the ridge in a plan view.   4. The semiconductor laser device according to claim 2, wherein a plurality of island portions of the current injection blocking layer are arranged in the longitudinal direction so as to be divided in a plan view.   The semiconductor laser device according to claim 4, wherein the total length of the island portion along the longitudinal direction is 30% to 70% of the length of the first electrode layer.   The semiconductor laser device according to claim 2, wherein a width of the island portion is 40% to 80% of a width of the first electrode layer. A semiconductor laminated body having a ridge formed on the surface;
A first electrode layer disposed on the ridge in contact with the semiconductor laminated body and extending in the longitudinal direction;
A current injection blocking layer that covers at least a part of the upper surface from the side surface of the first electrode layer;
A second electrode layer disposed on the current injection blocking layer,
The second electrode layer contacts a portion of the first electrode layer,
The current injection blocking layer has a plurality of protrusions connected from one edge of both edges of the first electrode layer extending in the longitudinal direction to the other edge.
The semiconductor laser device according to claim 1, wherein the plurality of protrusions are evenly distributed in the longitudinal direction of the first electrode layer in a plan view.   The semiconductor according to claim 1, wherein the current injection blocking layer contacts the first electrode layer in 18% to 80% of a contact area between the first electrode layer and the semiconductor stacked body. Laser device.   The semiconductor according to any one of claims 1 to 8, wherein the second electrode layer contacts the first electrode layer at 30% to 82% of a contact area between the first electrode layer and the semiconductor stacked body. Laser device. The semiconductor laser device according to claim 1, wherein the current injection blocking layer is made of an insulating material.