TW202127760A - Semiconductor laser element - Google Patents

Abstract

Provided is a semiconductor laser element for which the scope of application of a laser structure is broad and in which sufficient heat dissipation is ensured. The semiconductor laser element comprises: a semiconductor laminate in which are laminated a plurality of semiconductor layers including a first electrically conductive semiconductor layer, an active layer, and a second electrically conductive semiconductor layer in the stated order; an insulation layer in which, of the entire region of the side opposite from the active-layer side of the first electrically conductive semiconductor layer, an injection range within which carriers can be injected is reserved extending along the oscillation direction of light in the active layer, the insulation layer being laminated on said opposite side; a plurality of first electrodes that are ohmic with respect to the first electrically conductive semiconductor layer and are each connected to the injection range, the first electrodes being mutually separated in the oscillation direction at least within the injection range, and including a main electrode and a sub-electrode for which the connection area with the injection range is smaller than that of the main electrode; and a second electrode that is connected to each of the plurality of first electrode and is non-ohmic with respect to the first electrically conductive semiconductor layer.

Description

Semiconductor laser components

The present invention relates to semiconductor laser components.

In recent years, the application of nitride semiconductor lasers has progressed as a laser light source for exposure machines and 3D printers. In addition, the nitride semiconductor laser system has advantages such as miniaturization, cost reduction, and high performance of the device, and therefore, high output is required.

However, the vicinity of the emission end face of the semiconductor laser element causes large light absorption due to the occurrence of defects during cleavage and the shrinking of the energy band gap, and the temperature rise in the vicinity of the emission end face becomes a problem with the increase in output. That is, the temperature rise at the end surface is a problem of "rapid device degradation caused by the dissolution of the crystal portion of the end surface (hereinafter referred to as COD)" and "abrupt drop in laser output in the high current region (hereinafter referred to as IL). The reason for the drop)” has become an important issue before realizing a large-output and highly-reliable semiconductor laser element.

For the purpose of suppressing the aforementioned rapid drop in COD and IL, for example, Patent Document 1 discloses that the width of the p-side ohmic electrode on the emission side is set to be sufficiently smaller than the width of the p-side ohmic electrode in the center of the element to suppress the end face of the emission side. Nearby fever technology. In addition, Patent Document 2 discloses a technique of covering a p-side ohmic electrode with a p-side Schottky electrode to improve heat dissipation and suppress COD.

In addition, Patent Document 3 discloses a technique for suppressing COD by improving the heat dissipation near the end surface by setting the width of the p-side electrode near the end surface sufficiently wider than the p-side electrode at the center of the element to improve the heat dissipation near the end surface.

In addition, Patent Document 4 discloses a technique in which the same material as the sheet electrode is provided in the vicinity of the end surface and the heat-dissipating layer is electrically separated to improve heat-dissipation and suppress COD. Furthermore, Patent Document 5 discloses a technique for improving heat dissipation and suppressing COD by providing a thermally conductive film made of AlN or Si near the end surface. [Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent No. 6160141 [Patent Document 2] JP 2003-31894 A [Patent Document 3] JP 2010-114202 A [Patent Document 4] JP 2011-258883 A [Patent Document 5] JP 2010-41035 A

[The problem to be solved by the invention]

In the technique described in Patent Document 1, the width of the p-side ohmic electrode on the emission side needs to be sufficiently smaller than the width of the p-side ohmic electrode in the center of the element. For example, in the case of a thin laser structure with a stripe platform such as a single-mode laser having a width of, for example, 2 μm or less, it is technically difficult to form thinner electrodes on the stripe platform with a high yield. Therefore, the technique described in the aforementioned Patent Document 1 limits the applicable laser structure.

In addition, in the technique described in Patent Document 2, the heat dissipation depends on the thermal conductivity of the p-side Schottky electrode, etc. Therefore, the heat generation at the end surface due to the high output of the laser gradually increases, and it is difficult to ensure sufficient heat dissipation. Sexual condition. Furthermore, even in the techniques described in Patent Document 3, Patent Document 4, and Patent Document 5, for the same reason as Patent Document 2, it may be difficult to ensure sufficient heat dissipation.

Therefore, the subject of the present invention is to provide a semiconductor laser element that has a wide range of applications for a laser structure, especially in the vicinity of the end surface, which can ensure sufficient heat dissipation and suppress heat generation. [Means to solve the problem]

In order to solve the aforementioned problems, the semiconductor laser element of the present invention includes: a semiconductor laminate, a plurality of semiconductor layers including a p-type semiconductor layer, an active layer, and an n-type semiconductor layer; and an insulating layer. , Leaving the entire region of the p-type semiconductor layer on the side opposite to the active layer side, extending along the oscillation direction of the active layer light rays and injecting the carrier injection range, layered on the opposite side; The 1p-side electrode is ohmic contact for the p-type semiconductor layer, respectively connected to the injection range, at least within the injection range, isolated from the oscillation direction, and the connection area including the main electrode and the injection range is smaller than the main electrode The secondary electrode; and the second p-side electrode, which are connected to the plurality of first p-side electrodes individually, are in non-ohmic contact with the p-type semiconductor layer.

According to this semiconductor laser element, the structure of separating the secondary electrode from the main electrode suppresses heat generation at the end and also ensures sufficient heat dissipation. As a result, it is possible to suppress a sudden drop in COD and I-L. In addition, the structure of the semiconductor laser element described above can be applied to a wide range of laser structures including a laser structure having a narrow stripe platform width.

In the semiconductor laser element, the second p-side electrode reaches the end of the oscillation direction in the entire region on the opposite side, and it is preferable that the outermost surface of the end is not Au. In this ideal structure, the Au on the end face can be prevented from sagging even if the end part is split during the manufacture of the semiconductor laser element.

In the aforementioned structure in which the outermost surface of the end is not Au, the second p-side electrode has better solder wettability on the outermost surface of the end than other parts. In such an ideal structure, it is possible to suppress the entry and exit of the solder on the end surface during the so-called downward joint mounting.

Furthermore, in the aforementioned structure in which the outermost surface of the end portion is not Au, it is preferable that the outermost surface of the second p-side electrode at least overlaps with the first p-side electrode is Au. In this ideal structure, the Au on the outermost surface promotes heat dissipation.

In the semiconductor laser element, the total length in the oscillation direction of the non-injection region that is not in contact with the first p-side electrode in the injection range is relative to the total length in the oscillation direction of the optical resonator of the semiconductor laser element It is preferably 10% or less. Alternatively, the total area of the non-injection region that is not in contact with the first p-side electrode in the injection range is preferably 10% or less with respect to the total area of the injection range. If the part that does not become a gain in the laser oscillation exceeds 10% of the total, the gain is insufficient, which may hinder the high output of the semiconductor laser element. In the semiconductor laser element, the plurality of first p-side electrodes extend beyond the injection range, and may be connected to each other outside the injection range.

In addition, in the semiconductor laser element, the plurality of first p-side electrodes are smaller than the distance between the two edges of the injection range in the width direction intersecting the oscillation direction, and do not reach any edge. good. With this structure, spatial hole burning can be suppressed, so the laser oscillation mode is stable.

Furthermore, in the semiconductor laser element, the shape of the secondary electrode is preferably a shape in which the length of the oscillation direction is longer than the end in the center part of the width direction intersecting the oscillation direction. With this structure, the carrier density in the center of the injection range is higher than that at the ends, so the lateral vibration mode of the semiconductor laser element is easily stabilized in a single mode. [Effects of the invention]

According to the semiconductor laser element of the present invention, the application range of the laser structure is wide, and sufficient heat dissipation can be ensured, or heat generation can be suppressed.

Hereinafter, the embodiments of the present invention will be explained based on the drawings.

The embodiment described below is an example of the means for implementing the present invention, and should be appropriately modified or changed according to the structure and various conditions of the device to which the present invention is applied, and the present invention is not limited to the following embodiments. In addition, in the drawings described below, the same reference numerals are attached to components that are the same or have the same function even in different embodiments, and redundant descriptions are omitted. Furthermore, each drawing is a schematic diagram that is easily understood when referring to the following description, and it is not necessarily drawn on a scale of a certain scale. <The first embodiment>

1 to 6 are diagrams showing the first embodiment of the semiconductor laser device of the present invention. 1 shows a top view, FIG. 2 shows a longitudinal cross-sectional view along the optical resonator, FIG. 3 shows a cross-sectional view A-A, FIG. 4 shows a cross-sectional view B-B, FIG. 5 shows a cross-sectional view C-C, and FIG. 6 shows a cross-sectional view D-D.

The semiconductor laser device 100 has an n-type semiconductor layer 101, an active layer 102, and a p-type semiconductor layer 103 laminated in this order, and each of these layers is made of, for example, a nitride semiconductor. In addition, each of these layers has a layered structure in which a plurality of layers are stacked as an internal structure. When the semiconductor laser element 100 is a refractive index waveguide type laser, as the layer structure of the n-type semiconductor layer 101, for example, a layer structure of a laminated substrate, a coating layer, and a guide layer is adopted as the layer structure of the p-type semiconductor layer 103 For example, a layered structure in which a guiding layer, a coating layer, and a contact layer are laminated.

Hereinafter, the direction in which the n-type semiconductor layer 101 and the active layer 102 and the p-type semiconductor layer 103 are laminated in a laminated body is referred to as the "layering direction". That is, the stacking direction is the direction perpendicular to the paper surface in the plan view, and the vertical cross-sectional view, the A-A cross-sectional view, the B-B cross-sectional view, the C-C cross-sectional view, and the D-D cross-sectional view are the upper and lower directions. In the following description, the direction from the n-type semiconductor layer 101 side to the p-type semiconductor layer 103 side in the stacking direction is referred to as "up" regardless of the direction of gravity, and the opposite direction is regardless of gravity. The direction is called the "down" situation.

The semiconductor laser element 100 has a shape extending in the left-right direction in a plan view, and light is reflected at both ends of the direction to form an optical resonator. The emission side of the light in the semiconductor laser element 100 is, for example, the left side of FIG. 1, and the length of the optical resonator is, for example, 800 μm. The optical resonator extends along the direction in which the semiconductor laser element 100 extends. Hereinafter, the direction in which the optical resonator extends is referred to as the resonance direction. That is, the resonance direction is the left-right direction in the top view and the vertical cross-sectional view, and the direction perpendicular to the paper surface in the A-A cross-sectional view, the B-B cross-sectional view, the C-C cross-sectional view, and the D-D cross-sectional view.

In the semiconductor laser element 100 of the first embodiment, on the upper part of the p-type semiconductor layer 103, a stripe platform 103a is formed that protrudes in the stacking direction to the opposite side of the active layer 102 and extends in the resonance direction. The width of the strip-shaped platform 103a is, for example, 2 μm in this embodiment, and insulating layers 120 are formed on both sides of the strip-shaped platform 103a. Hereinafter, the direction in which the insulating layer 120 sandwiches the strip-shaped platform 103a is referred to as the condition of the width direction. That is, the width direction is the upper and lower directions in the plan view, the direction perpendicular to the paper in the longitudinal section, and the left and right directions in the A-A sectional view, the B-B sectional view, the C-C sectional view, and the D-D sectional view. In addition, there are situations in which the dimensions in the width direction are referred to as "width".

The semiconductor laser device 100 of the first embodiment has a plurality of first electrodes 111 formed on the p-type semiconductor layer 103 and the insulating layer 120 and straddling the strip-shaped platform 103a in the width direction. The first electrode 111 is an electrode that is ohmically connected to the p-type semiconductor layer 103. As an example, the first electrode 111 has a layer structure in which a plurality of metal materials are laminated. As the layer structure of the first electrode 111, for example, a layer structure in which Pd, Ti, Pt, and Au are sequentially stacked from the bottom is used. In this layer structure, although the Pd in the lowermost layer achieves ohmic connection with the p-type semiconductor layer 103, the adhesion of Pd to the insulating layer 120 is low.

The main electrode 111m of the plurality of first electrodes 111 is a large electrode extending in the resonance direction, and the sub-electrode 111s of the plurality of first electrodes 111 is in the resonance direction and is separated from the main electrode 111m and the sub-electrodes 111s are also separated from each other less than the main electrode. The electrode 111m is a small electrode. In this embodiment, a plurality of sub-electrodes 111s are formed, and each of the sub-electrodes 111s is an electrode having a long rectangular shape in the width direction.

In addition, in the present embodiment, a plurality of sub-electrodes 111s are formed. However, only one sub-electrode 111s may be formed. In addition, in this embodiment, the secondary electrode 111s is formed on the light emitting end side. However, the secondary electrode 111s may be formed on both ends individually. The secondary electrode 111s shown in FIG. 1 can be easily formed even for a thin strip-shaped platform 103a having a width of 2 m or less.

The semiconductor laser device 100 of the first embodiment further has a second electrode 112 on the first electrode 111. The second electrode 112 is spread more widely in the resonance direction and the width direction than the first electrode 111, strongly adheres to the insulating layer 120, and suppresses peeling of the first electrode 111. The second electrode 112 is in non-ohmic contact with the p-type semiconductor layer 103.

As an example, the second electrode 112 has a layer structure in which a plurality of metal materials are laminated. As the layer structure of the second electrode 112, for example, a layer structure in which Ti, Pt, and Au are sequentially stacked from the bottom is used. In this layer structure, Ti in the lowermost layer achieves strong adhesion to the insulating layer 120, and Au in the uppermost layer promotes heat dissipation. In the end 112a of the second electrode 112 in the resonance direction, the uppermost layer of Au is peeled off, and Pt is exposed. The end portion 112a is, for example, a range from the end surface of the semiconductor laser element 100 to 20 μm.

By peeling the Au, during the manufacture of the semiconductor laser device 100, even if the end face is split, the Au film can be prevented from dropping on the end face, causing short circuit or shielding the emitted light. In addition, by exposing Pt, even in a situation where the upper surface of the semiconductor laser element 100 is soldered to the sub-holder by so-called downward bonding and mounting, the end portion 112a has low solder wettability. Therefore, it is possible to suppress problems such as short-circuiting or shielding of emitted light by the solder around the end surface of the semiconductor laser element 100.

An n-side electrode 113 is formed under the n-type semiconductor layer 101. By applying a voltage between the p-side electrode and the n-side electrode 113 that merge the first electrode 111 and the second electrode 112, a current flows through the active layer 102 to emit light. Here, with regard to the range of the upper surface of the p-type semiconductor layer 103 that is not covered by the insulating layer 120 (that is, the upper surface of the strip-shaped mesa 103a in this embodiment), the first electrode 111 is formed to enable carrier Where it’s injected. In the following description, this area may be referred to as a carrier injection range.

Even in the carrier injection range, that is, within the range of the stripe platform 103a, no carrier is injected into the portion where the first electrode 111 is not formed, and only the portion where the first electrode 111 is formed and which is in contact with the first electrode 111 is injected. . In addition, the second electrode 112 is in non-ohmic contact with the p-type semiconductor layer 103, so even if the second electrode 112 is in contact with the carrier injection range, no carriers will be injected. The plurality of first electrodes 111 are formed in a range separated by a distance of, for example, 10 μm from both ends of the semiconductor laser element 100 (that is, both ends of the optical resonator). Therefore, the area of 10 μm at both ends of the optical resonator becomes a non-injection area where no carriers are injected.

The current flowing through the active layer 102 flows only in a region of the active layer 102 suitable for the carrier injection range to be in contact with the first electrode 111, and this region becomes the gain region 130 capable of amplifying light. The gain region 130 is amplified, and the light beams that repeat the round trip are reflected at both ends of the resonance direction to become laser light, which is emitted from the semiconductor laser element 100.

Regarding the plurality of first electrodes 111, they are arranged to be separated from each other in the carrier injection range, and the spaces between the first electrodes 111 are non-injected regions where no carriers are injected. Therefore, as shown in FIG. 1, the gain region 130 is also divided into a plurality of pieces in the resonance direction, and the heat generated in the gain region 130 has a high heat dissipation structure. In addition, by dividing the gain area 130 into a plurality of pieces, the heat generation itself can also be suppressed. As a result, in the semiconductor laser element 100, it is possible to suppress a sudden drop in COD and I-L.

Here, the distance between the first electrodes 111 that achieve good characteristics in the semiconductor laser element 100 will be reviewed. If the distance between the first electrodes 111 increases, the heat dissipation will increase, but on the other hand, the size of the non-implanted region will also increase. If the non-implanted region is too large, the characteristics of the semiconductor laser element 100 may deteriorate. In addition, the influence of the presence of the non-implanted region on the characteristics of the semiconductor laser element 100 is the size of the non-implanted region 1, and the total size of the non-implanted region contributes more. Therefore, the inventors of the present application conducted various tests on the semiconductor laser element 100 having the structure shown in FIGS. 1 to 6 in which the distance between the first electrodes 111 is different to measure the output characteristics. FIG. 7 is a graph showing the relationship between the size of the non-injected region and the output characteristics of the semiconductor laser device.

The horizontal axis of FIG. 7 represents the size of the non-injection region located between the plurality of first electrodes 111 by the total length in the resonance direction (hereinafter referred to as "non-injection length between electrodes"). In addition, the vertical axis of Fig. 7 represents the input current value of the axis on the left when a sudden drop in COD or IL occurs (hereinafter referred to as the "sudden drop current value"), and the axis on the right represents the light output when a current of 1A is input ( Hereinafter referred to as "1A light output"). In the graph of FIG. 7, the current value of the sudden drop generation current is represented by a circle mark, and the 1A light output is represented by an × mark. However, the circular mark and the x mark shown on the axis on the left are the values of the comparative example in which the first electrode 111 has only the main electrode 111m and does not have the sub-electrode 111s.

It can be confirmed that the current value of the sudden drop generation is higher than that of the comparative example even in a situation where the non-injection length between the electrodes is a short separation interval of 10 μm. The current value of the sudden drop is gradually increased with the increase of the non-injection length between the electrodes. On the other hand, if the non-injection length between the electrodes of the 1A light output system increases, it will gradually decrease, and if the non-injection length between the electrodes exceeds 60 μm, the ratio of the decrease in the 1A light output will increase. In this way, if the non-injection length between the first electrodes 111 exceeds 60 μm, the output characteristics of the semiconductor laser element 100 will be significantly reduced.

The output characteristic of the semiconductor laser device 100 shown here can be said to be one of the oscillation characteristics of an optical resonator. Then, the oscillation characteristic of the optical resonator is predicted to depend on the ratio of the non-injected area to the total length of the optical resonator. The foregoing graph reveals that the total length of the optical resonator of the semiconductor laser element 100 with output characteristics is 800 μm, and there are 10 μm non-injected regions at both ends of the optical resonator. Therefore, according to the graph shown in FIG. 7, it can be understood that the comparison is If the ratio of the non-injected area to the total length of the optical resonator exceeds 10%, the output characteristics will be significantly reduced. Conversely, if the ratio of the non-injected region to the total length of the optical resonator is 10% or less, the decrease in light output due to the light loss in the non-injected region can be suppressed, and the current value of the sudden drop generation current can be increased. <The second embodiment>

8-12 are diagrams showing the second embodiment of the semiconductor laser device of the present invention. FIG. 8 shows a top view, FIG. 9 shows a longitudinal cross-sectional view along the optical resonator, FIG. 10 shows a cross-sectional view of A-A, FIG. 11 shows a cross-sectional view of B-B, and FIG. 12 shows a cross-sectional view of E-E.

Compared with the semiconductor laser device 100 of the first embodiment, the semiconductor laser device 200 of the second embodiment has a wider width of the stripe platform 103a, for example, 20 μm. In addition, the length of the resonator is, for example, 1000 μm.

In the semiconductor laser element 200 of the second embodiment, unlike the semiconductor laser element 100 of the first embodiment, the first electrode 111 is accommodated inside the width of the strip-shaped platform 103a, and neither of the first electrodes 111 is provided. Reach the edge of the strip platform 103a. In addition, the widths of the first electrodes 111 are equal to each other.

In the semiconductor laser element 200 of the second embodiment, the width of the first electrode 111 is narrower than the width of the stripe-shaped mesa 103a, so the area exceeding the width of the first electrode 111 becomes a non-injection area where no carriers are injected.

The width of the gain area is also narrower than the width of the strip-shaped platform 103a. When the width of the strip-shaped platform 103a is wider, the gain region is narrower than the strip-shaped platform 103a, and the oscillation mode (horizontal lateral vibration mode) is stabilized as described below. FIG. 13 is a diagram showing the oscillation mode of the comparative example, and FIG. 14 is a diagram showing the oscillation mode of the semiconductor laser element of the second embodiment.

Here, as a comparative example, imagine a semiconductor laser element in which the first electrode 111 is formed on a stripe platform 103a having a width of 20 μm, and the width of the stripe platform 103a is filled.

The horizontal axis of FIGS. 13 and 14 represents the position in the width direction of the semiconductor laser element of the comparative example and the second embodiment, and the vertical axis represents the carrier density and photon density of the active layer 102.

In the case of the comparative example, as shown by the dotted line in FIG. 13 at the start of oscillation, the carrier density becomes almost uniform throughout the full width of the carrier injection range corresponding to the strip-shaped platform 103a, and the light oscillates. At this time, the optical density of the mode of the oscillating light is, for example, as shown by the dotted line in FIG. 13, and it becomes a high density in the center. More injected carriers will be consumed in the high optical density region of the light pattern, so a kind of space burning will occur in the region where the local carrier density is reduced in the carrier injection range. As a result, as shown by the solid line in the example shown in FIG. 13, the carrier density becomes high in both end portions in the width direction. The light amplification system becomes stronger in the region where the carrier density is relatively high. Therefore, when the carrier density changes from the state shown by the dotted line in FIG. The pattern shown by the solid line in Fig. 13 in which spikes of photon density occur at both ends in the width direction where the density is high.

If this mode lasts for a certain period of time, more carriers will be consumed at both ends of the carrier injection range than in the center. Therefore, returning to the carrier density shown by the dotted line, the oscillation mode becomes a high optical density in the center. model. This mode transition is repeated in the comparative example, and the oscillation mode will be unstable. In particular, in the case of a laser structure with a carrier injection range wider than the carrier diffusion length, because the oscillation mode of the light is unstable, kinking of the photo-current characteristics and a far view depending on the driving conditions may occur Therefore, it is impossible to obtain practically desirable characteristics.

In contrast, in the semiconductor laser element of the second embodiment, the first electrode 111 is narrower than the carrier injection range, and the first electrodes 111 are not formed at both ends of the carrier injection range in the width direction. As a result, as shown by the dotted line in FIG. 14, from the start of oscillation, the carrier density at both ends of the carrier injection range is almost zero, and the carrier density is low at the center of the width direction of the carrier injection range. peak.

As a result, the oscillation mode becomes a mode in which the photon density is high in the center of the carrier injection range. Then, in a situation where this mode continues, as shown by the solid line, although the carrier density and photon density in the center part will decrease, the carrier density and photon density will not be reversed in the center part and both ends. reverse. Therefore, the space burning like the comparative example can be suppressed, and the oscillation mode can be stabilized. Hereinafter, return to FIGS. 8 to 12 to continue the description.

In the semiconductor laser element 200 of the second embodiment, similar to the semiconductor laser element 100 of the first embodiment, as the first electrode 111, a main electrode 111m and a sub-electrode 111s are formed. Long rectangular electrode. In the semiconductor laser element 200 of the second embodiment, the plurality of first electrodes 111 are also separated from each other in the resonance direction, so the first electrodes 111 form a non-injection region where no carriers are injected, as shown in FIG. 9 , The gain area 130 is also divided into plural in the resonance direction. Therefore, high heat dissipation is achieved, heat generation is also suppressed, and a sudden drop in COD and I-L is suppressed.

In addition, the semiconductor laser element 200 of the second embodiment is the same as the semiconductor laser element 100 of the first embodiment, and further includes a second electrode 112 on the first electrode 111. In addition, in the end 112a in the resonance direction of the second electrode 112, the uppermost layer of Au is peeled off, and Pt is exposed. In the second embodiment, the end portion 112a is a range from the end surface of the semiconductor laser element 200 to 10 μm, for example, and the end portion 112a does not reach the first electrode 111. That is, in the portion of the second electrode 112 that overlaps the first electrode 111, the uppermost layer becomes Au. In the portion where the uppermost layer is Au, the heat dissipation is promoted by Au. Therefore, since the uppermost layer of the portion overlapping the first electrode 111 is Au, the heat accompanying the optical amplification can be efficiently dissipated. As a result, the COD can be further suppressed. And IL dropped sharply. <The third embodiment>

15-19 are diagrams showing the third embodiment of the semiconductor laser device of the present invention. 15 shows a top view, FIG. 16 shows a longitudinal cross-sectional view along the optical resonator, FIG. 17 shows a cross-sectional view A-A, FIG. 18 shows a cross-sectional view B-B, and FIG. 19 shows a cross-sectional view E-E.

Compared with the semiconductor laser device 100 of the first embodiment and the semiconductor laser device 200 of the second embodiment, the semiconductor laser device 300 of the third embodiment has a wider width of the stripe platform 103a, for example, 40 μm. The length of the resonator is, for example, 1200 μm. In the semiconductor laser element 300 of the third embodiment, a plurality of first electrodes 111 are also formed, and a second electrode 112 is further formed on the first electrode 111.

In the third embodiment, unlike the first and second embodiments, the second electrode 112 does not reach the end of the semiconductor laser element 300 in the resonance direction. In the end 112a of the second electrode 112 in the resonance direction, the uppermost layer of Au is peeled off, and Pt is exposed. In the third embodiment, the end 112a of the second electrode 112 is in a range of, for example, 10 μm in the resonance direction.

In the semiconductor laser element 300 of the third embodiment, as in the first and second embodiments, the main electrode 111m and the sub-electrode 111s are formed as the first electrode 111, but it is different from the first and second embodiments. The individual widths of the plurality of first electrodes 111 are not uniform, and the width of the secondary electrode 111s is narrower than the width of the main electrode 111m. In addition, the main electrode 111m spreads wider than the width of the strip-shaped platform 103a, and the sub-electrode 111s is accommodated inside the width of the strip-shaped platform 103a.

In this way, the main electrode 111m and the sub-electrode 111s have different widths. Therefore, in the semiconductor laser device 300 of the third embodiment, the gain region 130 corresponding to the main electrode 111m is diffused to the width of the stripe platform 103a (that is, the carrier injection However, the gain region 130 corresponding to the secondary electrode 111s is narrower than the width of the strip-shaped platform 103a.

Furthermore, in the semiconductor laser element 300 of the third embodiment, the shape of the secondary electrode 111s is not a rectangular shape, but is an elliptical shape or a convex lens shape. That is, the shape of the secondary electrode 111s is a shape in which the length in the resonance direction is longer in the center of the width direction and shorter in the end.

In the situation of the first electrode 111 of the third embodiment formed by the main electrode 111m and the sub-electrode 111s, the first electrodes 111 are also separated from each other in the resonance direction, and become a non-injection region where no carriers are injected. The area 130 is divided into a plurality of parts in the resonance direction. Therefore, the semiconductor laser element 300 of the third embodiment also has high heat dissipation properties, can suppress heat generation, and can suppress the rapid decrease of COD and I-L.

Furthermore, as in the semiconductor laser element 300 of the third embodiment, the length of the secondary electrode 111s in the resonance direction differs depending on the position in the width direction, as the ratio of the non-injected area that affects the output characteristics of the semiconductor laser element 300 It is better to measure it not by length but by area. That is, in order to obtain good output characteristics in the semiconductor laser element 300, the total area of the non-injected region is preferably 10% or less with respect to the total area of the implanted range.

In addition, by forming the gain region 130 using the main electrode 111m and the sub-electrode 111s as described above, the oscillation mode (horizontal lateral mode) can be stabilized as described below. Fig. 20 is a diagram showing the oscillation mode of the semiconductor laser device of the third embodiment. The horizontal axis of FIG. 20 represents the position in the width direction of the semiconductor laser element of the third embodiment, and the vertical axis represents the carrier density and photon density of the active layer 102.

In the semiconductor laser element 300 of the third embodiment, the wide-width main electrode 111m provides carriers almost evenly over the full width of the carrier injection range. On the other hand, the narrow sub-electrode 111s provides a concentrated supply of carriers to the center of the carrier injection range. As a result, as shown by the broken line, the carrier density covering the full width of the carrier injection range generates a certain level or more, and a high peak of the carrier density is generated at the center of the width direction of the carrier injection range. As a result, the oscillation mode becomes a mode in which the photon density is high in the center of the carrier injection range.

In addition, when this mode is continued, as shown by the solid line, although the carrier density in the center portion decreases, but the full-width carrier density covering the carrier injection range is reduced to a certain level, it will be caused by the 111s of the secondary electrode. The supply balances, and the reduction stops. Then, the photon density is maintained in a high mode in the center of the carrier injection range as indicated by the solid line. That is, even in the situation of the third embodiment, the cavity burning in the space as shown in FIG. 13 can be suppressed, and the oscillation mode can be stabilized.

In addition, even if the instability of the horizontal lateral vibration mode of light occurs in the area corresponding to the main electrode 111m, the luminous light system often passes through the area corresponding to the sub-electrode 111s during the amplification process, so it will act on the level of suppressed light. The direction of the instability of the transverse mode. <The fourth embodiment>

21 to 24 are diagrams showing the fourth embodiment of the semiconductor laser device of the present invention. FIG. 21 shows a top view, FIG. 22 shows a longitudinal cross-sectional view along the optical resonator, FIG. 23 shows a cross-sectional view A-A, and FIG. 24 shows a cross-sectional view B-B. In the semiconductor laser element 400 of the fourth embodiment, the width of the stripe platform 103a is, for example, 50 μm, and the length of the resonator is, for example, 1500 μm.

The semiconductor laser element 400 of the fourth embodiment is the same as the semiconductor laser element 100 of the first embodiment, and a plurality of first electrodes 111 are formed on the strip-shaped platform 103a. In addition, the first electrode 111 includes a main electrode 111m with a longer length in the resonance direction on the strip-shaped platform 103a, and a secondary electrode 111s with a shorter length in the resonance direction. The main electrode 111m and the secondary electrode 111s extend to a strip shape. The outside of platform 103a.

In the semiconductor laser device 400 of the fourth embodiment, unlike the semiconductor laser device 100 of the first embodiment, the main electrode 111m and the sub-electrode 111s pass through the bridge portion 111i on the outside of the stripe platform 103a. A second electrode 112 is further formed on the bridge portion 111i.

Even if it is connected to the outside of the strip platform 103a, the main electrode 111m and the secondary electrode 111s are separated in the resonance direction on the strip platform 103a, and the first electrodes 111 form a non-injection region where no carriers are injected. Therefore, As shown in FIG. 22, the gain region 130 is also divided into plural in the resonance direction. As a result, the semiconductor laser element 400 of the fourth embodiment also has high heat dissipation properties, can suppress heat generation, and can suppress the rapid decrease of COD and I-L. <Fifth Embodiment>

25 to 28 are diagrams showing the fifth embodiment of the semiconductor laser device of the present invention. FIG. 25 shows a top view, FIG. 26 shows a longitudinal cross-sectional view along the optical resonator, FIG. 27 shows a cross-sectional view A-A, and FIG. 28 shows a cross-sectional view B-B.

In the semiconductor laser element 500 of the fifth embodiment, the length of the resonator is, for example, 800 μm. In addition, in the fifth embodiment, no stripe-shaped mesa is formed, and a portion of the upper surface of the p-type semiconductor layer 103 that is not covered by the insulating layer 120 becomes the carrier injection range 103b. The width of the carrier injection range 103b is, for example, a large width of 100 μm.

The semiconductor laser element 500 of the fifth embodiment is also the same as the semiconductor laser element 100 of the first embodiment, and a plurality of first electrodes 111 having a width wider than that of the carrier injection range 103b are formed in the carrier injection range 103b. Separate configuration inside. As the first electrode 111, a main electrode 111m having a longer length in the resonance direction and a secondary electrode 111s having a shorter length in the resonance direction are formed. The first electrodes 111 form a non-injection region where no carriers are injected. Therefore, as shown in FIG. 26, the gain region 130 is divided into a plurality of parts in the resonance direction, and the heat generated in the gain region 130 has high heat dissipation. The structure can also suppress heat generation. As a result, in the semiconductor laser element 500, the rapid decrease of COD and I-L can be suppressed.

In addition, the plurality of first electrodes 111 have a uniform structure covering the full width of the wide carrier injection range 103b, and the light rays going to and from the optical resonator will be amplified anywhere in the wide carrier injection range 103b, and nothing happens. Where to lose. Therefore, in the semiconductor laser element 500 of the fifth embodiment, instead of destabilizing the horizontal lateral vibration mode, any mode is amplified, and a stable high output can be obtained as a whole.

In addition, in each of the above-described embodiments, examples have been disclosed that both improve heat dissipation and suppress heat generation. However, the semiconductor laser element of the present invention can be used to achieve only one of enhanced heat dissipation and suppression of heat generation.

100, 200, 300, 400, 500: semiconductor laser components 101: n-type semiconductor layer 102: active layer 103: p-type semiconductor layer 103a: Strip platform 103b: Carrier injection range 111: first electrode 111m: main electrode 111s: secondary electrode 111i: Bridge 112: 2nd electrode 112a: end 113: n-side electrode 120: Insulation layer 130: gain area

[Fig. 1] A plan view showing the first embodiment of the semiconductor laser device of the present invention. [Fig. 2] A longitudinal sectional view showing the first embodiment of the semiconductor laser device of the present invention. [FIG. 3] A-A cross-sectional view showing the first embodiment of the semiconductor laser device of the present invention. [Fig. 4] A B-B cross-sectional view showing the first embodiment of the semiconductor laser device of the present invention. [Fig. 5] A C-C cross-sectional view showing the first embodiment of the semiconductor laser device of the present invention. [FIG. 6] A D-D cross-sectional view showing the first embodiment of the semiconductor laser device of the present invention. [Figure 7] A graph showing the relationship between the size of the non-injected region and the output characteristics of the semiconductor laser device. [Fig. 8] A plan view showing the second embodiment of the semiconductor laser device of the present invention. [Fig. 9] A longitudinal sectional view showing the second embodiment of the semiconductor laser device of the present invention. [Fig. 10] A-A cross-sectional view showing the second embodiment of the semiconductor laser device of the present invention. [FIG. 11] A B-B cross-sectional view showing the second embodiment of the semiconductor laser device of the present invention. [Fig. 12] An E-E cross-sectional view showing the second embodiment of the semiconductor laser device of the present invention. [Fig. 13] A diagram showing the oscillation mode of the comparative example. [Fig. 14] A diagram showing the oscillation mode of the semiconductor laser element of the second embodiment. [Fig. 15] A plan view showing the third embodiment of the semiconductor laser device of the present invention. [Fig. 16] A longitudinal sectional view showing the third embodiment of the semiconductor laser device of the present invention. [FIG. 17] A-A cross-sectional view showing the third embodiment of the semiconductor laser device of the present invention. [FIG. 18] A B-B cross-sectional view showing the third embodiment of the semiconductor laser device of the present invention. [Fig. 19] An E-E cross-sectional view showing the third embodiment of the semiconductor laser device of the present invention. [Fig. 20] A diagram showing the oscillation mode of the semiconductor laser device of the third embodiment. [Fig. 21] A plan view showing the fourth embodiment of the semiconductor laser device of the present invention. [Fig. 22] A longitudinal sectional view showing the fourth embodiment of the semiconductor laser device of the present invention. [Fig. 23] A-A cross-sectional view showing the fourth embodiment of the semiconductor laser device of the present invention. [Fig. 24] A B-B cross-sectional view showing the fourth embodiment of the semiconductor laser device of the present invention. [FIG. 25] A plan view showing the fifth embodiment of the semiconductor laser device of the present invention. [FIG. 26] A longitudinal sectional view showing the fifth embodiment of the semiconductor laser device of the present invention. [FIG. 27] A-A cross-sectional view showing the fifth embodiment of the semiconductor laser device of the present invention. [FIG. 28] A B-B cross-sectional view showing the fifth embodiment of the semiconductor laser device of the present invention.

100: Semiconductor laser components

103a: Strip platform

111: first electrode

111m: main electrode

111s: secondary electrode

112: 2nd electrode

112a: end

120: Insulation layer

Claims (10)

A semiconductor laser component, which is characterized by: A semiconductor layered body, which includes a first conductivity type semiconductor layer, an active layer, and a plurality of semiconductor layers different from the first conductivity type semiconductor layer of the second conductivity type; The insulating layer leaves the entire region of the first conductivity type semiconductor layer on the side opposite to the active layer side, extending along the oscillation direction of the active layer light rays and injecting the carrier injection range, laminated on the opposite side side; The plurality of first electrodes are connected to the injection range in ohmic contact with the first conductivity type semiconductor layer, and are separated from each other in the oscillation direction at least within the injection range, and include the ratio of the connection area between the main electrode and the injection range The main electrode is a small secondary electrode; and The second electrode is connected to the plurality of first electrodes individually, and is in non-ohmic contact with the first conductivity type semiconductor layer. The semiconductor laser element described in claim 1, wherein: The first conductivity type semiconductor is a p-type semiconductor, and the second conductivity type semiconductor is an n-type semiconductor; The first electrode and the second electrode are respectively a first p-side electrode and a second p-side electrode. The semiconductor laser element as described in claim 2, in which: The second p-side electrode reaches the end of the oscillation direction in the entire region on the opposite side, and the outermost surface of the end is not Au. The semiconductor laser element described in claim 3, wherein: In the second p-side electrode, the solder wettability on the outermost surface of the end portion is lower than that of the other portions. The semiconductor laser element described in claim 3, wherein: In the second p-side electrode, at least the outermost surface of the portion overlapping the first p-side electrode is Au. The semiconductor laser element as described in claim 2, in which: The total length in the oscillation direction of the non-injection region that is not in contact with the first p-side electrode in the injection range is 10% or less of the total length in the oscillation direction of the optical resonator of the semiconductor laser element. The semiconductor laser element as described in claim 2, in which: The total area of the non-injection region that is not in contact with the first p-side electrode in the injection range is 10% or less with respect to the total area of the injection range. The semiconductor laser element as described in claim 2, in which: The plurality of first p-side electrodes extend beyond the injection range, and are connected to each other outside the injection range. The semiconductor laser element as described in claim 2, in which: The plurality of first p-side electrodes are smaller than the interval between the two edges of the injection range in the width direction intersecting the oscillation direction, and do not reach any edge. The semiconductor laser element as described in claim 2, in which: The shape of the secondary electrode is a shape in which the length of the oscillation direction is longer than the end in the central part of the width direction intersecting the oscillation direction.

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