JP5347566B2 - Semiconductor light emitting device and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor light emitting element capable of bringing an FFP into a favorable Gaussian shape of reduced ripple, and to provide a semiconductor light emitting element capable of enhancing a close tightness between a resonator end face and a protection film, capable of increasing manufacturing efficiency, and capable of reducing a manufacturing cost. <P>SOLUTION: This semiconductor light emitting element includes a substrate, a semiconductor layer laminated on the substrate, and a protrusion formed on an end face in a resonator side of the semiconductor layer, the protrusion has a light emitting face and a side face, a top view shape of the protrusion has a continuous wave-like shape or irregular shape, and the side face of the protrusion has an area of surface roughness larger than that of the light emitting face. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a semiconductor light emitting device, and more particularly to a semiconductor light emitting device having a protrusion on an end face of a semiconductor layer on a resonator side.

  In recent years, various studies have been made on the structure of semiconductor light emitting devices, and among them, many research reports have been made on semiconductor laser devices and edge emitting LEDs which are edge emitting devices. A structure for controlling the shape of light emitted from a light emitting element, called a light emission mode, and a structure for achieving high output, long life, and improved reliability have been proposed.

  In a semiconductor laser, a stripe structure is formed for controlling the transverse mode of light, and light generated in the stripe-shaped waveguide region is resonated. At this time, if light leaks from the waveguide region including the active layer, the leaked light is emitted as stray light to the outside of the semiconductor laser. As a result, noise is added to the main laser beam, and ripples appear in the FFP (far field pattern). In particular, this phenomenon becomes more prominent as the output of the semiconductor laser is increased. Since such ripple, which is noise, causes various troubles when coupled to an optical fiber or a lens, a semiconductor light emitting element capable of realizing FFP without ripple is required.

  For example, in Patent Document 1, a nitride semiconductor laser including a nitride semiconductor layer having a ridge stripe formed on a substrate, an electrode formed thereon, and an emission end face perpendicular to the longitudinal direction of the ridge stripe. In the element, an opening (concave portion) is formed in a portion where the ridge stripe in the vicinity of the emission end face is not provided, and the surface excluding the bottom surface of the concave portion is made rougher than the top surface of the nitride semiconductor layer. .

  Patent Document 2 discloses a semiconductor element in which a group III nitride-based semiconductor layer is formed on a substrate, although the structure is not a countermeasure against ripple, and is regular or irregular on the side surface of the group III nitride-based semiconductor layer. There is a semiconductor element in which a typical uneven pattern is formed. An insulating film is formed on the side surface of the semiconductor element, and such a structure prevents peeling of the insulating film.

JP 2006-287137 A JP 2001-185802 A

  However, in the semiconductor laser element, ripple suppression is still insufficient. Therefore, the yield may be reduced.

Furthermore, the protection film peels off or deteriorates due to the heat generated at the resonator end face, and the adhesion between the resonator end face and the protection film is kept good. There is a strong demand to suppress peeling, further increase manufacturing efficiency, and reduce manufacturing costs.

  Accordingly, an object of the present invention is to provide a semiconductor light emitting device in which FFP has a good Gaussian shape with little ripple. It is another object of the present invention to provide a semiconductor light emitting device capable of improving the adhesion between the resonator end face and the protective film, increasing the production efficiency, and reducing the production cost.

  The semiconductor light-emitting device of the present invention is a semiconductor light-emitting device having a substrate, a semiconductor layer stacked on the substrate, and a protrusion formed on an end surface of the semiconductor layer on the resonator side. It has a light emission surface and a side surface, and the planar view shape of the side surface of the protruding portion has a continuous wavy shape or a concavo-convex shape, and the side surface of the protruding portion is surface rougher than the light emission surface. Has a large area.

  The semiconductor light-emitting device of the present invention is a semiconductor light-emitting device having a substrate, a semiconductor layer stacked on the substrate, and a protrusion formed on an end surface of the semiconductor layer on the resonator side. It has a light emission surface and a side surface, the planar view shape of the side surface of the protruding portion has a continuous wavy shape or an uneven shape, and the side surface of the protruding portion has a protruding portion It is characterized by.

Moreover, it is preferable that the semiconductor light emitting element described above further includes any one or more of the following.
(1) The protrusion formed on the side surface of the protrusion extends in a direction substantially parallel to the growth surface of the semiconductor layer.
(2) The shape of the protrusion in plan view is narrower in the light exit surface direction.
(3) The semiconductor light emitting device has an exposed region of a semiconductor layer or a substrate in front of the protruding portion.
(4) A protective film is formed on the light emitting surface and the side surface of the protrusion.
(5) The semiconductor light emitting device is a semiconductor laser device or an edge emitting LED.
(6) The protrusion is formed by etching.

  The method of manufacturing a semiconductor light emitting device according to the present invention includes a substrate, a semiconductor layer stacked on the substrate, and a protrusion formed on an end surface of the semiconductor layer on the resonator side. A step of laminating a semiconductor layer on a substrate; and forming a resonator-side end surface on the semiconductor layer, and forming a protrusion having a light emitting surface and a side surface on the resonator-side end surface. And a step of forming a protruding portion on the side surface of the projecting portion.

  In the method for manufacturing the semiconductor light emitting device described above, the step of making the planar shape of the side surface of the protruding portion a continuous wave shape or the uneven shape and the step of forming the protruding portion on the side surface of the protruding portion can be performed simultaneously. preferable. Thereby, manufacturing efficiency can be improved.

According to the semiconductor light emitting device of the present invention, a desired light emission mode can be provided. Further, according to the semiconductor laser device of the present invention, it is possible to suppress the FFP ripple of the laser light.

  Moreover, according to the semiconductor light emitting device of the present invention, it is possible to improve the adhesion between the end face on the resonator side and the protective film formed on the end face. This can improve the reliability and life characteristics of the semiconductor light emitting device.

  Further, for example, the resonator end faces of a plurality of semiconductor light emitting elements in wafer units can be formed by one etching step, and the manufacturing efficiency can be improved. The resonator end face in the vicinity of the active layer of the semiconductor layer has a very good surface shape, and it becomes possible to manufacture a semiconductor light emitting device having characteristics equivalent to those obtained by cleaving the resonator end face. .

It is a schematic perspective view for demonstrating the structure of the semiconductor light-emitting device concerning one embodiment of this invention. It is a schematic top view of the principal part for demonstrating the structure of the semiconductor light-emitting device which concerns on one embodiment of this invention. It is a schematic sectional drawing for demonstrating the structure of the semiconductor light-emitting device concerning one embodiment of this invention. It is the schematic perspective view which expanded the principal part for demonstrating the structure of the semiconductor light-emitting device concerning one embodiment of this invention. 4 is an enlarged photograph of a protrusion of the nitride semiconductor laser device of the present invention. It is a graph which shows FFP-X of the nitride semiconductor laser element of this invention. It is a graph which shows FFP-X of the nitride semiconductor laser element of a comparative example.

FIG. 1 is a perspective view showing a semiconductor laser device according to an embodiment of the present invention. A substrate 10 and a semiconductor layer 20 are stacked on the substrate, and a protrusion 31 is provided on an end surface of the semiconductor layer on the resonator side. The protruding portion 31 has a light emitting surface 32 and a side surface 33. When the protrusion is viewed in plan, the shape of the side surface 33 has a continuous wave shape. Further, the side surface 33 of the protruding portion 31 has a region 33 a having a surface roughness larger than that of the light emitting surface 32.

Here, the continuous wavy shape is the shape of the side surface 33 when viewed in plan as shown in FIG. 2, and this shape extends in a meandering manner rather than a straight line. Also, there are those that connect U-shaped patterns and those that connect reverse dome-shaped patterns. Here, the width of one U-shaped or inverted dome-shaped pattern is in the range of about 2 μm to 15 μm. Further, the height of the U-shaped or inverted dome-shaped pattern in plan view is in the range of about 0.5 μm to 20 μm.

Further, the region 33a having a surface roughness larger than that of the light emitting surface 32 on the side surface 33 of the projecting portion 31 is confirmed by the magnitude relation of the surface roughness when the surface state is evaluated using a known observation method. It can be done. For example, a region 33a where the surface roughness is large with respect to the arithmetic average roughness of the light exit surface 32 when evaluated by arithmetic average roughness, maximum height, ten-point average roughness, etc. according to JISB0601 (1994). The arithmetic average roughness of is 1.5 times or more.
In addition, in the region 33a where the surface roughness is large, the height difference of the surface unevenness is larger than the height difference of the surface unevenness on the light emitting surface of the protruding portion 31.

  FIG. 3 is a sectional view showing the semiconductor laser device according to the embodiment of the present invention. A substrate 10 and a semiconductor layer 20 are stacked on the substrate, and a protrusion 31 is provided on an end surface of the semiconductor layer on the resonator side. The protruding portion has a light emitting surface 32 and a side surface 33.

  Further, in the semiconductor laser device according to the embodiment of the present invention, when the protrusion is viewed in plan, the shape of the side surface 33 may have a continuous uneven shape. Further, the side surface 33 of the protruding portion 31 has a region 33 a having a surface roughness larger than that of the light emitting surface 32.

  Here, the continuous concavo-convex shape is a shape of the side surface 33 when the protruding portion 31 is viewed in plan, and this shape has a corner portion and extends stepwise. The concavo-convex shape is a shape that is meandering from side to side instead of a straight line, and one of the patterns has corners. Moreover, the side surface of the protrusion part of this invention may be provided with this uneven | corrugated shape and the waveform pattern mentioned above. The side surface of the protruding portion of the present invention preferably has a high proportion of the wavy shape when it has an uneven shape and a wavy pattern.

  In other words, the side surface 33 of the projecting portion 31 has a protrusion on the side surface 33 of the side surface 33 of the light emitting surface 32. (FIG. 1). The protrusion is formed on the side surface 33 of the protrusion 31 in parallel with the direction in which the wavy shape or the uneven shape extends, and the width and height are irregularly connected like a mountain range. Is.

The protrusion formed on the side surface of the protrusion preferably extends in a direction substantially parallel to the growth surface of the semiconductor layer. The width of this protrusion is 0.1 μm to 5.0 μm, and the length is 2 μm to 30 μm. The protrusion may be partially disconnected both in the width direction and in the length direction, but preferably has no disconnection and extends continuously in a direction substantially parallel to the growth surface of the semiconductor layer. Is. Moreover, as shown in FIG. 3, it is preferable that the protrusion is formed in a plurality of streaks in the stacking direction of the semiconductor layer on the side surface of the protrusion. Such a configuration can effectively suppress lateral ripple.
The height of the protrusion is 0.1 μm to 4.0 μm from the substrate surface. If the height of the protrusion is within this range, the adhesiveness of the protective film formed on the end face can be favorably maintained while exhibiting the ripple suppression effect.

  It is preferable that the planar shape of the protrusion 31 is narrower in the light exit surface direction (FIG. 2). Thus, the effect of this invention mentioned above further improves because the side surface 33 of a protrusion part inclines with respect to the light-projection surface. The reason will be described below. The stray light leaking from the end face on the resonator side in the semiconductor light emitting element is mainly caused by light emitted to the outside from the region including the side surface 33 of the protruding portion in the present invention and its vicinity. For this reason, it is necessary to consider whether to block light emitted from this region to the outside, or to allow stray light to escape from this region in a direction other than the light exit surface direction. In the present invention, the projection in plan view has a wavy shape or an uneven shape, and the side surface of the projection has a region having a surface roughness larger than that of the light exit surface. It is possible to block stray light from being emitted in the direction of the light exit surface. Furthermore, the planar shape of the protruding portion 31 has a wavy shape or an uneven shape, and even if some stray light is emitted to the outside from the side surface of the protruding portion by narrowing in the light emitting surface direction, this The stray light is emitted in a direction other than the light exit surface direction.

  FIG. 4 is an enlarged schematic perspective view of a main part for explaining the structure of the semiconductor light emitting device according to the embodiment of the present invention. The planar view shape of the side surface 33 of the protruding portion in the semiconductor light emitting device here is an inverted dome shape, and this pattern is continuously connected. Further, this side surface has a region 33a having a larger surface roughness than the light emitting surface. Here, a plurality of regions 33a having a large surface roughness exist in one reverse dome-shaped pattern. Such a configuration is effective in suppressing ripples. Further, as shown in FIG. 4, the region 33a having a large surface roughness may be present continuously from one reverse dome-shaped pattern to another adjacent pattern. The shape of this side surface is formed on both side surfaces of the protrusion. Further, the region 33a having a large surface roughness is formed continuously in a direction parallel to the growth surface of the semiconductor layer, and when the cross-sectional shape is a mountain range having a triangular shape, This is expressed as a protrusion. The above explanation is for the case where the planar view shape of the side surface of the protruding portion is an inverted dome shape, but the explanation here also applies to the case where the planar view shape of the side surface of the protruding portion is another shape. Needless to say, it can be applied.

  The semiconductor light emitting device 50 has an exposed region of the semiconductor layer or the substrate in front of the protruding portion. With such a configuration, in the process of converting the wafer shape into a bar shape, the process of converting the bar shape into a chip shape, or the process of converting the wafer shape into a chip shape directly No damage to the protrusions occurs, and the semiconductor layer or the exposed region of the substrate formed at the tip of the protrusions absorbs the damage generated in these steps.

  A protective film is formed on the light emitting surface 32 and the side surface 33 of the protruding portion 31. With such a configuration, the reflectance of light emitted from the light emitting surface 32, for example, laser light, can be adjusted. In addition, the combination with the side surface shape of the protruding portion described above improves the adhesion of the protective film, thereby improving the reliability of the semiconductor light emitting element.

  The semiconductor light emitting device 50 is a semiconductor laser device or an edge emitting LED. If the semiconductor light emitting device of the present invention is a semiconductor laser device, it is particularly effective as a laser light source for optical disc applications by suppressing ripples. In addition, the edge-emitting LED is also effective as a light source with excellent directivity.

  The protrusion 31 is preferably formed by etching. When this protrusion is formed in the process of making a bar shape or a chip shape from a wafer shape, which is one step of the manufacturing process of the semiconductor light emitting device, the protrusion may be damaged. Such a problem is solved by performing the formation process of the portion by etching. In order to increase the strength of the protrusion 31, it is conceivable to increase the width of the light emission surface of the protrusion. However, stray light may be emitted from the light emission surface. The width of the surface is preferably in the range of 1.0 μm to 10.0 μm. Moreover, the length of a side surface is 2.0 micrometers or more, Preferably it is set as the range of 2.0 micrometers-30.0 micrometers.

Thus, the light leaked from the waveguide region of the semiconductor laser can be scattered by setting the protrusion formed on the end face on the resonator side as described above. Therefore, leakage light emitted in the direction of the main beam of the laser can be reduced, and an FFP with suppressed ripples can be obtained.
Moreover, the mode hop of the vertical direction can also be suppressed. By reducing the ripple of the FFP of the laser light, coupling with an optical system member such as a lens or an optical fiber or lens design is facilitated.

  The semiconductor layer 20 is formed by sequentially laminating a first conductivity type semiconductor layer 21, an active layer 22, and a second conductivity type semiconductor layer 23. Here, the first conductivity type semiconductor layer 21 is an n-side semiconductor. The second conductivity type semiconductor layer 23 is a p-side semiconductor layer. In addition, a stripe-shaped ridge 14 is formed in the second conductivity type semiconductor layer 23, and a stripe-shaped waveguide region is formed below the ridge portion.

A protective film is formed on the end face on the resonator side. This protective film may be referred to as an end face protective film (not shown). The end face protective film is a dielectric film and is a single layer or a multilayer thereof.
Further, the protective film formed on the side surface of the striped ridge 14 may be referred to as a buried film (not shown). A p-electrode 41 is formed on the striped ridge 14. A p-pad electrode 42 is formed on the p-electrode, and an n-electrode (not shown) or the like is appropriately formed on the back surface of the substrate.

  The region 33a having a large surface roughness formed on the side surface of the protrusion formed on the end surface of the semiconductor layer on the resonator side is preferably formed in the active layer or the first conductivity type semiconductor layer 21. The reason is that light leaked from the waveguide region of the semiconductor laser is absorbed by the electrode formed on the second conductivity type semiconductor layer when leaked to the second conductivity type semiconductor layer 23 side. However, since the light leaking to the first conductivity type semiconductor layer propagates to the substrate 10 side or leaks to the outside from the side surface of the first conductivity type semiconductor layer 21, countermeasures against ripples are more demanded. Because. Light that leaks to the outside can be suppressed by forming a region having a large surface roughness in the active layer on the side surface of the protrusion or the semiconductor layer of the first conductivity type. In addition, light leaking to the outside can be further suppressed by forming a region having a large surface roughness in the active layer on the side surface of the protruding portion and the semiconductor layer of the first conductivity type.

Growth of Semiconductor Layer The semiconductor laser device of this embodiment has an SCH (Separate Confinement Heterostructure) structure in which light guide layers are formed on both sides of the active layer. Further, an n-side cladding layer and a p-side cladding layer are formed on both sides thereof. The clad layer is provided with a nitride semiconductor layer having a low refractive index to confine light. The clad layer also has a carrier confinement effect. Moreover, it is good also as a structure which has a stress buffer layer between each said layer. However, the present invention is not limited to the above SCH structure, and may have a structure without a light guide layer.

  Observation of the end face on the resonator side and the protruding portion is, for example, a transmission electron microscope (TEM), a scanning transmission electron microscope (STEM), a scanning electron microscope (SEM). ) And the like. Further, by such observation, the difference between the side surface of the protruding portion and the light emitting surface, and the protruding portion formed on the side surface of the protruding portion can be confirmed. The photograph shown in FIG. 5 is an SEM photograph observing the protruding portion of the semiconductor laser device of the present invention. As can be seen from this photograph, a region having a larger surface roughness than the light exit surface is formed on the side surface of the protrusion. The region having a large surface roughness is formed in a range of about 0.1 μm to 5.0 μm in the height direction of the semiconductor layer, and is formed in a length of 2.0 μm or more in the direction of the side surface. It is preferable. This region is formed in a region including the active layer of the stacked semiconductor layers. Such a semiconductor laser element is a semiconductor laser element in which the occurrence of ripples is suppressed.

  The observation of the protruding portion of the semiconductor light emitting device of the present invention is not limited to the above-described observation, and the surface state of the resonator end face can be evaluated using a known method. For example, you may evaluate by arithmetic mean roughness by JISB0601 (1994) etc., maximum height, ten-point average roughness, etc. Further, the surface roughness of the boundary region may be quantified and evaluated by an atomic force microscope (AFM). For example, arithmetic average roughness can be evaluated by using a scanning probe microscope (SPI3800N) manufactured by SII Nano Technology.

  The light emitting surface 32 of the protruding portion formed on the resonator-side end surface in the present invention has an arithmetic average roughness of about 2.5 to 4.5 nm, and the surface roughness on the side surface 33 of the protruding portion. It is preferable that the region 33a having a large has an arithmetic average roughness of about 5.0 to 9.0 nm. In the side surface 33 of the protruding portion 31, it is preferable that the region other than the region 33 a having a large surface roughness has a surface roughness of about the light emitting surface 32. If the surface roughness of the light emitting surface is not within the above range, the shape of light emitted from the light emitting surface, for example, laser light, cannot be made desired. Furthermore, it is preferable that the region 33a having a large surface roughness on the side surface 33 of the protruding portion has a rough surface about 1.5 to 3.0 times the light emitting surface. This effectively removes lateral ripple.

  The end face on the resonator side is usually formed by dry etching, but the shape of the protrusion formed on the end face on the resonator side depends on the shape of the mask used at that time. The shape of the mask is a wave shape or an uneven shape when viewed from the top, and is formed by taking over the mask shape from the stacked semiconductor layers. In addition, the region or protrusion that has a large surface roughness formed on the side surface of the protrusion depends on the etching conditions (etchant type and flow rate, RF power, pressure, temperature, etching time, etc.) of the semiconductor layer, It can be formed by appropriately controlling these. Specifically, when the semiconductor layer is a nitride semiconductor layer, the pressure is set to a low vacuum so that the pressure is in the range of about 0.5 Pa to 40 Pa, and the RF power is variable to be in the range of about 50 to 1000 W. And the like. In addition, since the end face on the resonator side is formed by etching, the process for forming the end face protective film on the light emitting face in the subsequent process can be formed in one process from the wafer state. Efficiency can be improved.

The shape of the mask when viewed from the top is a wave-like shape with respect to the substrate surface. The U-shaped shape, the U-shaped shape is connected vertically, and the U-shape meanders left and right. . The shape of the mask when viewed from the top is an uneven shape, which is a shape having a step in the direction of the resonator from the light exit surface side. Further, the material of the mask is not particularly limited, but for example, a resist, an insulator such as SiO ₂ or the like is used.

Embodiments of a semiconductor light emitting device and a method for manufacturing the same according to the present invention will be described below in detail with reference to the drawings. However, the present invention is not limited to this.
Example 1
The semiconductor light emitting device of this embodiment relates to a laser device made of a nitride semiconductor. As shown in FIG. 1 and FIG. 2, a first semiconductor layer (n-side nitride semiconductor layer) 21, an active layer and a ridge 14 formed on the surface are formed on a GaN substrate 10 having a C plane as a growth surface. A semiconductor layer (p-side nitride semiconductor layer) 23 is laminated in this order, and an end face on the resonator side is formed.

A projecting portion 31 is formed on the end face on the resonator side, and the projecting portion 31 has a light emitting surface 32 and a side surface 33.
In addition, in this semiconductor laser element, end face protective films (not shown) are formed on the front end face and the rear end face of the resonator end face. This protective film may be a single layer film or a multilayer film. A p-electrode 41, a p-pad electrode 42, an n-electrode (not shown), etc. are formed.

As a method for manufacturing a nitride semiconductor laser device, first, a substrate 10 made of n-type GaN having a thickness of 400 μm is set in an MOCVD reaction vessel, and the following semiconductor layers are stacked to form a device structure. The surface of the substrate 10 is a C plane (0001), and the following semiconductor layers are stacked in order. As the first semiconductor layer (n-side semiconductor layer), a 2 μm thick Si-doped Al _0.03 Ga _0.97 N n-side cladding layer and a 175 nm thick GaN n-side guide layer are stacked. Next, a 14 nm-thickness Si-doped In _0.02 Ga _0.98 N barrier layer and a 7 nm-thickness Si-doped In _0.07 Ga _0.93 N well layer were repeated twice as the active layer. A barrier layer is laminated on the substrate. Next, as a second nitride semiconductor layer (p-side semiconductor layer), a 10-nm thick Mg-doped Al _0.3 Ga _0.7 N electron confinement layer, a 145-nm thick GaN p-side guide layer, and various film thicknesses A p-side cladding layer having a thickness of 0.45 μm, a p-side contact layer of Mg-doped GaN having a thickness of 15 nm, and a superlattice having a thickness of 2.5 nm Mg-doped Al _0.1 Ga _0.9 N and GaN stacked alternately. Laminate.

Next, after a wafer having a nitride semiconductor layer on the substrate 10 is taken out of the reaction vessel, a SiO ₂ mask having a desired shape is formed on the p-side contact layer. As the shape of the mask here, the region where the light emission surface of the protrusion is formed is linear, and the region where the side surface is formed is wavy. Thereafter, etching is performed from the p-side contact layer side to the middle of the n-side cladding layer through this mask to form a protruding portion 31 on the end face on the resonator side. The shape of the side surface of the protruding portion 31 in plan view is a continuous wave shape. At this time, the width of the light emitting surface 32 in the protruding portion 31 is 6 μm, and the height of the light emitting surface 32 is 4 μm. The length of the side surface 33 is about 10 μm.

The width of the light exit surface is 2.5 μm between the stripe-shaped ridge 14. Further, the height of the light emitting surface formed on the protruding portion is 4 μm, and the length of the side surface is 10 μm. At this time, a region 33a having a rough surface is formed on the side surface of the protruding portion. The surface roughness of this region 33a is about 6.0 nm as the arithmetic average roughness of AFM observation. The width of the region 33a is about 2 μm, and the length is about 10 μm. Several regions 33a are formed on the side surface (FIG. 5).
As etching conditions for forming the protrusion, reactive ion etching (RIE) is used, the flow rate of CHF ₃ gas is 5 to 200 sccm, the flow rate of O ₂ gas is 1 to 100 sccm, and the pressure is 0. Etching SiO ₂ under conditions of 5 to 30 Pa and RF power of 50 to 1000 W to form a substantially vertical mask. The protrusion is formed by forming the mask in this way.

Here, as etching conditions for forming the protrusion and further exposing the substrate, RIE is used, the flow rate of Cl ₂ gas is 10 to 200 sccm, the flow rate of SiCl ₄ gas is 1 to 100 sccm, and the pressure is 0.5 to The condition is 40 Pa and RF power is 50 to 1000 W. Thus, the semiconductor layer is etched to form a protruding portion on the end face on the resonator side, and is also etched in a direction perpendicular to the end face on the resonator side. The etching depth at this time is such that the n-side cladding layer is exposed from the surface of the p-side contact layer. Further, about 4 μm is etched to etch a part of the substrate. A part of the substrate 10 is exposed in a region in front of the light emitting surface 32 of the projecting portion on the resonator side. The exposed area of the substrate is a divided area for forming a bar shape or a chip shape from the wafer.

Next, a striped ridge 14 is formed. Subsequently, a mask pattern made of striped SiO ₂ having a width of 2.0 μm is formed on the surface of the p-side contact layer, which is the uppermost layer of the semiconductor layer, and etched using Cl-containing gas using RIE. The stripe-shaped ridge 14 is formed by etching to the vicinity of the interface between the layer and the p-side light guide layer.

  Here, as the dimensions of the semiconductor laser element, the resonator length can be in a range of 200 to 1000 μm and the width can be in a range of about 50 to 500 μm. In the first embodiment, the dimension of one element region is set such that the length in the resonator direction is 300 μm (resonator length), and the width of the semiconductor laser element perpendicular to the resonator direction is 120 μm.

Next, an embedded film (not shown) made of ZrO ₂ having a thickness of 200 nm is formed on the surface of the nitride semiconductor layer and on the side surface of the ridge. Subsequently, the p-side electrode 41 is formed in a stripe shape wider than the ridge 24 on the ridge outermost surface of the p-side contact layer. The p-side electrode 41 is formed in the order of Ni / Au / Pt on the surface above the p-side contact layer and the buried film. Next, after forming the p-side electrode, an end face protective film is formed. This end face protective film is formed using a sputtering apparatus. This end face protective film forms Al ₂ O ₃ on the light emitting surface side. Furthermore, (SiO ₂ / ZrO ₂ ) is formed in four periods on the resonator end face on the reflection side. Thereafter, the p-side pad electrode 42 is formed on the p-side electrode 41.

Next, the back surface of the n-type GaN substrate 10 is mechanically polished to a wafer thickness of about 80 μm.
Then, the back surface of the GaN substrate 10 is subjected to chemical mechanical polishing (CMP) to further flatten the nitrogen polar surface. Thereafter, Ti / Pt / Au is sequentially laminated on the back surface of the GaN substrate 10 to form an n-side ohmic electrode (not shown).

  Further, the laser scribing apparatus scans the laser beam to form the division assist groove in the semiconductor wafer. However, this step can be omitted. In this embodiment, split auxiliary grooves that are substantially perpendicular and substantially parallel to the end face are formed simultaneously. Moreover, although the division | segmentation auxiliary groove can be formed with a broken line or a stripe, since the influence of the dust on the end surface part at the time of laser scanning can be considered, the broken line is desirable for the division auxiliary groove substantially parallel to the end face.

Further, since the protruding portion 31 has a convex shape, when the dividing auxiliary groove that is substantially parallel to the end surface on the resonator side is a broken line, it is possible to approach the end surface portion. This also improves the yield of chip formation.
Here, the distance between the end face portion and the auxiliary dividing groove substantially parallel to the end face can be in the range of about 0 to 10.0 μm. In this embodiment, the distance between the end face portion and the auxiliary dividing groove substantially parallel to the end face is 2 .5 μm.

  Next, the element regions are divided along the division auxiliary grooves. Chips may be formed from either of the auxiliary dividing grooves substantially perpendicular to and substantially parallel to the end face, or may be performed simultaneously using a roller break or the like.

  The semiconductor laser device thus obtained is a laser chip having an oscillation wavelength of about 405 nm, a resonator length of about 300 μm, and a width of about 120 μm. Then, after die bonding and wire bonding to a substrate such as a stem via a submount or conductive paste, a cap can be applied to obtain a semiconductor laser device.

  The surface roughness of the side surface of the protruding portion formed on the cavity-side end surface of the obtained semiconductor laser element is expressed as arithmetic average roughness: Ra as a scanning probe microscope (SPI3800N) device manufactured by SII Nanotechnology. And measured. As a result, the region having a large surface roughness on the side surface of the protruding portion was 6.66 nm on the light emitting surface and 2.57 nm.

Moreover, FFP-X was measured about the obtained semiconductor laser element. The measurement results of this example are shown in FIG. For comparison, FIG. 7 shows a measurement result of a semiconductor laser device in which the side view of the protruding portion has a linear shape in the plan view and does not form a region (protrusion) having a large surface roughness.
In the comparative example, as shown in FIG. 7, a ripple in the X direction appears remarkably when a part of the light leaked from the optical waveguide region including the active layer in the semiconductor laser element is emitted to the outside. On the other hand, in the semiconductor laser device of this example, as shown in FIG. 6, it was confirmed that the stray light as such a problem was eliminated by scattering, and the ripple in the X direction was suppressed.
As described above, the present invention provides a semiconductor light emitting device in which ripples are suppressed by forming a protrusion having a light emitting surface and a side surface on the end surface on the resonator side, and the side surface having the above-described configuration. Can do. Further, the shape of the side surface of the protruding portion makes it possible to improve the adhesion between the end face on the resonator side and the end face protective film, prevent the end face protective film from peeling off, and thus improve the COD level.

  The semiconductor light emitting device of the present invention can be used for, for example, a light emitting device such as a semiconductor laser and a light emitting diode, an electronic device such as a transistor, a light receiving device, a solar cell, and the like. Applications include, for example, illumination light sources, display light sources, optical disk light sources, optical communication system light sources, medical light sources, in-vehicle light sources, printing press light sources, exposure light sources, measuring instrument light sources, and bio-related excitations. Light source and the like.

10 substrate 14 ridge 20 semiconductor layer 21 first conductive type semiconductor layer (n-type semiconductor layer)
22 Active layer 23 Second conductivity type semiconductor layer (p-type semiconductor layer)
31 Projection part 32 Light emission surface 33 Side surface 33a Area where surface roughness is large

Claims (11)

In a semiconductor light emitting device having a substrate, a semiconductor layer stacked on the substrate, and a protrusion formed on an end surface of the semiconductor layer on the resonator side,
The protrusion has a light exit surface and a side surface,
Planar shape of the side surface of the protrusion is tapered in the light emitting surface direction in a continuous wave-like or stepped,
The side surface of the protrusion has a plurality of protrusions extending in a direction substantially parallel to the growth surface of the semiconductor layer . The semiconductor light emitting element according to claim 1, wherein the protrusion formed on the side surface of the protrusion has a stripe shape . The semiconductor light emitting element according to claim 1, wherein a shape of the projecting portion in plan view is an inverted dome shape . 4. The semiconductor light emitting element according to claim 1, wherein a side surface of the protruding portion has a region having a surface roughness larger than that of a light emitting surface. 5. The semiconductor light emitting element, a semiconductor light emitting device according to any one of claims 1 to 4 have exposed regions of the semiconductor layer or substrate in front of the projecting portion. The semiconductor light emitting element according to claim 1, wherein a protective film is formed on a light emitting surface and a side surface of the protruding portion. The semiconductor light-emitting element according to claim 1, wherein the semiconductor light-emitting element is a semiconductor laser element or an edge-emitting LED. The semiconductor light emitting element according to claim 1, wherein the protrusion is formed by etching. 9. The semiconductor light emitting element according to claim 1, wherein a height of the protruding portion is 0.1 μm to 4.0 μm from a substrate surface. In a method for manufacturing a semiconductor light emitting device, comprising: a substrate; a semiconductor layer stacked on the substrate; and a protrusion formed on an end surface of the semiconductor layer on a resonator side.
Laminating a semiconductor layer on a substrate;
Wherein to form a facet of the resonator side semiconductor layer, forming a projecting portion having a light emitting surface and the side to the end face of the resonator side, projecting portion plan view shape wave shape that is continuous with the side surface of the Or a step of making the light-emitting surface thinner in a staircase pattern,
Forming a plurality of protrusions extending in a direction substantially parallel to the growth surface of the semiconductor layer on a side surface of the protruding portion. 11. The method of manufacturing a semiconductor light emitting element according to claim 10 , wherein the step of forming a continuous wave shape or an uneven shape on the side surface of the protruding portion and the step of forming the protruding portion on the side surface of the protruding portion are performed simultaneously. .

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