JP2013077753A - Semiconductor laser and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor laser in which a semiconductor lasers (striped active layers) are disposed in high density.SOLUTION: A semiconductor laser comprises a plurality of active layers 10 which are provided in a striped pattern while being separated from each other, a plurality of electrodes 12 which are provided on an upper side of the active layers 10 correspondingly to each of the active layers 10, support parts 40 each of which is comprised of a semiconductor and provided in a region between the active layers 10 and the upper surfaces of which are located higher than the electrodes 12, and wiring 16 which is electrically connected with one of the plurality of electrodes 12, supported by a plurality of support parts 40 and has a structure to be separated from the electrodes 12 being positioned between the plurality of support parts 40.

Description

  The present invention relates to a semiconductor laser and a manufacturing method thereof.

  A semiconductor array laser in which a plurality of semiconductor lasers including an active layer are arranged in parallel is known. (For example, see Patent Document 1).

JP-A-10-90560

  In a conventional semiconductor array laser, a plurality of stripe-shaped electrodes are provided on the upper side of a plurality of stripe-shaped active layers arranged in parallel, and the electrodes are electrically connected to an electrode pad for signal transmission. Each electrode pad is formed in the vicinity of the striped electrode. However, in this configuration, in order to ensure the size of the electrode pad, it is necessary to form the stripe-shaped active layers at a certain distance or more, and it is difficult to arrange the stripe-shaped active layers at a high density.

  The present invention has been made in view of the above problems, and provides a semiconductor laser capable of easily realizing a configuration in which semiconductor lasers (striped active layers) are arranged at high density, and a method for manufacturing the same. For the purpose.

  The present invention comprises a plurality of active layers provided in stripes apart from each other, a plurality of electrodes provided on the upper side of the active layer corresponding to each of the active layers, and a semiconductor, A support portion provided in each of the regions between the active layers and having an upper surface positioned at a position higher than the electrode; electrically connected to one of the plurality of electrodes; and by the plurality of support portions A semiconductor laser comprising: a wiring that is supported and has a structure spaced apart from the electrode positioned between the plurality of support portions.

  In the above configuration, a plurality of electrode pads are formed in a region different from the region where the plurality of active layers are formed, and are electrically connected to any one of the plurality of electrodes via the wiring. Can do.

  The said structure WHEREIN: The side surface of the said support part can be set as the structure which becomes the taper shape which inclines toward the said electrode from the said upper surface of the said support part.

  The said structure WHEREIN: The space | interval of these active layers can be set as the structure which is 20 micrometers or less.

  In the above structure, the substrate includes a substrate on which the plurality of active layers are formed on the upper side, the surface of the substrate is a (100) plane, and at least a part of the side surface of the support portion has a (111) B plane. It can be set as a structure.

  The said structure WHEREIN: It can be set as the structure which is hollow between the said electrode and the said wiring formed in the upper part of the said electrode.

  In the above structure, a low dielectric having a dielectric constant of 4.0 or less may be filled between the electrode and the wiring formed on the electrode.

  The present invention includes a step of forming a plurality of striped mesas including an active layer on a substrate, a step of forming an electrode on the upper side of the striped mesas corresponding to each of the striped mesas, and a semiconductor A step of forming a support portion so that an upper surface is formed at a position higher than the electrodes in a region between the striped mesas, and electrically connected to one of the plurality of electrodes And a step of forming a wiring that is supported by the plurality of support portions and has a structure separated from the electrodes positioned between the plurality of support portions. .

  In the above configuration, the step of forming the wiring extends to the step of forming a resist on the upper portion of the electrode and the support portion formed in a region between the stripe-shaped mesas and the upper portion of the resist. The method may include a step of forming a wiring and a step of removing the resist.

  In the above configuration, the step of forming the wiring includes the step of forming a low dielectric layer having a dielectric constant of 4 or less on the electrode, and the support portion formed in a region between the striped mesas. And a step of forming a wiring so as to extend above the low dielectric layer.

  In the above configuration, the surface of the substrate may be a (100) plane, and the side surface of the striped mesa may be a (011) plane.

  The said structure WHEREIN: The process of forming the said support part can be set as the structure containing the process of adding halogen-type gas in addition to the raw material gas of the said support part.

  According to the present invention, it is possible to easily realize a configuration in which semiconductor lasers (stripe-shaped active layers) are arranged at high density.

1 is a top view of a semiconductor laser according to Comparative Example 1. FIG. FIG. 2 is a top view of the semiconductor laser according to the first embodiment. FIG. 3 is a perspective view of the semiconductor laser according to the first embodiment. FIG. 4 is a cross-sectional view of the semiconductor laser according to the first embodiment. FIG. 5 is a diagram illustrating the method of manufacturing the semiconductor laser according to the first embodiment. FIG. 6 is a view (No. 1) illustrating the method for manufacturing the semiconductor laser according to the second embodiment. FIG. 7 is a diagram (No. 2) illustrating the method for manufacturing the semiconductor laser according to the second embodiment. FIG. 8 is a top view of the semiconductor laser according to the third embodiment. FIG. 9 is a cross-sectional view of the semiconductor laser according to the third embodiment.

  First, a semiconductor laser according to a comparative example will be described. 1 is a top view of a semiconductor laser according to Comparative Example 1. FIG. As shown in FIG. 1, a plurality of bar-shaped semiconductor lasers (hereinafter referred to as stripe-shaped mesas 110a to 110d) including an active layer and upper and lower cladding layers (both not shown in FIG. 1) are arranged in parallel. ing. Each of the striped mesas 110a to 110d includes a striped active layer (not shown). Electrodes 112a to 112d are provided on the stripe-shaped active layer via contact layers (not shown), and the electrodes 112a to 112d are electrically connected to the electrode pads 114a to 114d, respectively. The electrode pads 114a to 114d are provided one by one between the electrodes 112a to 112d, and are located in the vicinity of the corresponding electrodes 112a to 112d.

  As shown in FIG. 1, in a semiconductor laser in which a plurality of striped mesas 110a to 110d including a striped active layer are arranged in parallel, in order to increase the density of the active layers, the striped mesa It is desirable to reduce (narrow) the interval between 110a to 110d. However, in the configuration in which the electrode pads 114a to 114d are provided between the striped mesas 110a to 110d, a certain space for forming the electrode pads 114a to 114d is required, and the striped mesas 110a to 110d It is difficult to reduce the interval. For example, the electrode pads 114a to 114d need to have a diameter of 70 μm or more and the distance between the striped mesas 110a to 110d needs to be 100 μm or more. In this case, the chip size of the semiconductor laser is 440 μm × 300 μm (L1 = 440 μm, L2 = 300 μm), and it is difficult to reduce it further.

  In the following examples, a semiconductor laser capable of easily realizing a configuration in which semiconductor lasers (stripe-shaped active layers) are arranged at high density and a method for manufacturing the same will be described.

  FIG. 2 is a top view of the semiconductor laser according to the first embodiment. In this embodiment, a Fabry-Perot (FP) type laser having a semi-insulating buried heterostructure (SIBH) will be described as an example. As shown in FIG. 2, a plurality of striped mesas 10a to 10d including a striped active layer are arranged in parallel. Electrodes 12a to 12d are formed on the upper surfaces of the striped mesas 10a to 10d. Of the end faces of the semiconductor laser crossing the extension lines (light guiding direction) of the striped mesas 10a to 10d, the first end face film 20 is provided on one end face, and the second end face film is provided on the other end face. 22 are formed. The first end face film 20 can have a thickness of 0.8 μm and a reflectance of 80%, for example, and the second end face film 22 can have a thickness of 0.4 μm and a reflectance of 30%, for example.

  The electrodes 12a to 12d on the striped mesas 10a to 10d are electrically connected to the electrode pads 14a to 14d, respectively. Here, unlike the comparative example, the electrode pads 14a to 14d are collectively formed in a region other than the region where the striped mesas 10a to 10d are formed, not between the striped mesas 10a to 10d. In this embodiment, as shown in FIG. 2, the first electrode pad 14a is formed at a predetermined interval from the striped mesa 10d (electrode 12d), and the second to fourth electrode pads 14b. ˜14d are formed at regular intervals so as to be arranged in an oblique direction as viewed from the first electrode pad 14a. The electrode pads 14a to 14d and the electrodes 12a to 12d are connected by bridge wires 16a to 16d, respectively. Although not illustrated, the electrode pads 14a to 14d are not arranged in an oblique direction as viewed from the first electrode pad 14a, but the electrode pad 14c is similar to the electrode pad 14a in a striped mesa 10d (electrode 12d). The electrode pad 14d is formed at a constant interval so as to be arranged in an oblique direction as viewed from the third electrode pad 14c, similarly to the electrode pad 14b. The structure which is may be sufficient.

  In this embodiment, the interval d1 between the striped mesas is 15 μm. At this time, the chip size of the semiconductor laser is 330 μm × 300 μm (L1 = 330 μm, L2 = 300 μm), which can be reduced as compared with the comparative example.

  FIG. 3 is a perspective view of the semiconductor laser according to the first embodiment. As shown in FIG. 3, each of the striped mesas 10 a to 10 d has a configuration in which a lower clad layer 32, an active layer 34, an upper clad layer 36, and a contact layer 38 are sequentially laminated on a substrate 30. Electrodes 12a to 12d are formed on the contact layers 38 of the striped mesas 10a to 10d. Buried layers 40a to 40e for separating the striped mesas from each other are formed between and outside the striped mesas 10a to 10d. The buried layers 40a to 40e are formed so as to rise from the striped mesas 10a to 10d, and the positions of the upper surfaces of the buried layers 40a to 40e are higher than the electrodes 12a to 12d.

  As shown in FIG. 2, the electrode pads 14a to 14d are formed on the opposite side of the electrode 12d of FIG. 3 toward the electrodes 12a to 12c (not shown in FIG. 3). For this reason, from the electrodes 12a to 12c on the left side of the electrode 12d, it is necessary to form wirings for electrical connection with the electrode pads 14a to 14d so as not to contact the electrodes 12b to 12d between them. .

  As shown in FIG. 3, 16a and 16b are illustrated among the bridge wirings 16a to 16d shown in FIG. The bridge wiring 16a is a wiring connecting the electrode 12a and the electrode pad 14a (not shown in FIG. 3), and is formed over the buried layers 40b to 40e. Similarly, the bridge wiring 16b is a wiring connecting the electrode 12b and the electrode pad 14b (not shown in FIG. 3), and is formed over the buried layers 40c to 40e.

  FIG. 4 is a cross-sectional view taken along the line AA in FIG. 2 and shows a detailed configuration of the bridge wiring 16a. As shown in FIG. 4, the bridge wiring 16a is a wiring that connects the upper surfaces of the buried layers 40b to 40e, and is formed apart from the electrodes 12b to 12d. A space 50 is formed between the bridge wiring 16a and the electrodes 12b to 12d. The buried layers 40a to 40e function as a support portion that supports the bridge wiring 16a. The side surfaces of the buried layers 40a to 40e are perpendicular to the lower side of the upper surface of the contact layer 38 and are inclined outward from the upper surface of the contact layer 38 to form a (111) B surface (reference numeral 42). Yes. For this reason, the shape of the opening between the buried layers 40a to 40e is a tapered shape that increases from the electrode side toward the bridge wiring side.

  In this embodiment, the interval d1 between the striped mesas 10a to 10d is 15 μm, the width d2 of the striped mesas 10a to 10d is 2 μm, and the height d3 of the raised portion of the striped mesas 10a to 10d is 5 μm. ing. Further, the upper surface width d4 of the buried layers 40a to 40e is 6 μm, the opening width d5 is 9 μm, and the inclination angle of the (111) B surface (reference numeral 42) is 54.7 °.

  Next, a method for manufacturing the semiconductor laser according to Example 1 will be described.

  FIGS. 5A to 5D are diagrams illustrating a method for manufacturing a semiconductor laser according to the first embodiment. As shown in FIG. 5A, a lower clad layer 32, an active layer 34, an upper clad layer 36, a contact layer 38, and a stripe mask 39 are formed on a substrate 30 in this order. As the substrate 30, for example, an n-InP substrate can be used, and the surface is a (100) plane. For example, an n-InP cladding layer having a thickness of 0.3 μm can be used for the lower cladding layer 32, and a p-InP cladding layer having a thickness of 1.6 μm can be used for the upper cladding layer 36, respectively.

The active layer 34 has an MQW (multiple-quantum well) structure including an SCH (separated confinement heterostructure) layer. For example, InGaAsP is used for the active layer 34, and the thickness thereof can be set to 0.3 μm, for example. The contact layer 38 may have a structure in which, for example, a p-InGaAsP intermediate layer having a thickness of 0.2 μm and a p-InGaAs contact layer having a thickness of 0.1 μm are sequentially stacked from the substrate 30 side. The stripe mask 39 is formed on the contact layer 38 so as to extend in the <011> direction. For the stripe mask 39, for example, SiO ₂ can be used.

  Next, as shown in FIG. 5B, using the stripe mask 39 as a mask, the contact layer 38, the upper clad layer 36, the active layer 34, the lower clad layer 32, and a part of the substrate 30 are dry-etched to form a stripe. A mesa 10 is formed. As a result, a stripe-shaped active layer 34 is formed inside the stripe mesa 10. The height of the striped mesa 10 can be set to 4 μm, for example.

  Next, as shown in FIG. 5C, a buried layer 40 serving as a support portion is grown on both sides of the striped mesa 10. In the buried layer 40, for example, S.I. I. An InP layer (Semi-Insulating InP: semi-insulating indium phosphide) can be used. In this case, a separation groove for separating the striped mesas 10a to 10d is not necessary. The thickness of the buried layer 40 is, in terms of (100) plane, for example, when the distance between the striped mesas 10a to 10d is 20 μm, and when the distance between the striped mesas 10a to 10d is 15 μm. It can be 6 μm. Thereby, a step (d3) of about 5 μm can be formed on both sides of the striped mesa 10.

  Here, in the step of growing the buried layer 40, it is preferable to add a halogen-based gas (for example, a gas containing chlorine (Cl) (such as methyl chloride)) in addition to the source gas of the buried layer 40. The halogen-based gas is not taken into the crystal of the buried layer 40, but plays a role of forming a (111) B surface (reference numeral) 42) in the buried layer 40. Thereby, the abnormal growth of the buried layer 40 on the stripe mask 39 can be suppressed.

  Next, as shown in FIG. 5D, the electrode 12 and the bridge wiring 16 are formed. After removing the stripe mask 39, a passivation film 44 is formed on the surface of the buried layer 40 and the region excluding the surface of the contact layer 38. For example, silicon nitride (SiN) can be used for the passivation film 44. Next, the electrode 12 is formed on the contact layer 38. For example, gold (Au) can be used for the electrode 12. Next, a resist (not shown) is formed in a region on the electrode 12 corresponding to the hollow 50 in the figure. Next, the bridge wiring 16 extending on the passivation film 44 on the upper surface of the buried layer 40 and on the resist is formed. For the bridge wiring 16, for example, Au can be used like the electrodes. Finally, by removing the resist, the region where the resist was present becomes the hollow 50, and the air bridge structure is completed. As described above, the bridge wiring 16 is formed so as to be separated from the electrode 12 through the hollow 50.

  According to the semiconductor laser of Example 1, the buried layer 40 is formed so as to rise in the region between the striped mesas 10 including the striped active layer 34, and the upper surfaces of the buried layers 40 are connected to each other. A bridge wiring 16 is formed. Thereby, the bridge wiring connecting the electrode on one active layer and the electrode pad can be separated from the electrode on the other active layer and crossed. As a result, as shown in FIG. 2, the electrode pads 14 a to 14 d can be collectively formed outside the striped mesas 10 a to 10 d using the bridge wirings 16 a to 16 d. As a result, the distance between the stripe-shaped active layers (stripe-shaped mesas 10a to 10d) can be reduced, and a configuration in which semiconductor lasers (stripe-shaped active layers) are arranged at high density can be realized. it can.

  The interval between the striped mesas 10a to 10d is preferably 20 μm or less, and more preferably 15 μm or less. This is because, by narrowing the interval between the striped mesas, the stepped portions of the adjacent striped mesas join (interference), so that even when the (100) plane is thin, a high step is formed. Because you can.

  In contrast to the above configuration, as a method of forming the bridge wiring and the electrode, it is conceivable that the wiring and the electrode are formed at the same height, and only a region where the wiring intersects with the electrode has a hollow bridge structure. However, in this structure, since the shape of the hollow bridge is convex upward, the hollow bridge of the wiring may be broken by pressure such as crushing. On the other hand, according to the semiconductor laser according to the first embodiment, since the inside of the step of the buried layer 40 is the hollow 50, the bridge wiring 16 can be formed flat. Thereby, it can suppress that the hollow bridge | bridging of wiring breaks with pressure, such as crushing.

  In addition, according to the semiconductor laser of Example 1, the manufacturing process is simplified by forming the step using the buried layers 40 on both sides of the striped mesa 10 as compared with the case where the step is formed by etching or the like. Can be In addition, by forming the side surface of the buried layer 40 (supporting portion) in a tapered shape that is inclined from the upper surface of the buried layer 40 toward the electrode 12, abnormal growth of the buried layer 40 in the manufacturing process can be suppressed.

  In the first embodiment, the case where the number of the striped mesas 10a to 10d including the striped active layer 34 is four is described as an example. However, the number of the striped mesas 10 may be an arbitrary number. The configuration of this embodiment is particularly suitable for a semiconductor laser including a plurality of striped mesas 10, electrodes 12, and bridge wirings 16, respectively. At this time, the wiring 16 formed on the top of one of the plurality of striped mesas 10 is connected to the electrode 12 formed on the upper surface of the other striped mesa 10. By doing so, the electrode pad 14 and the electrode 12 can be connected.

In the first embodiment, the hollow 50 is provided between the electrode 12 and the bridge wiring 16. However, a low dielectric having a dielectric constant of 4.0 or less may be filled instead of the hollow 50. This low dielectric is made of, for example, a material made of silicon nitride (SiN) or silicon oxide (SiO ₂ ). In this case, instead of forming a resist in the step of FIG. 5D, a low dielectric layer is formed on the electrode 12, and the low dielectric layer is left without being removed after the bridge wiring 16 is formed. As a result, the region corresponding to the hollow 50 in FIG. 4 is filled with the low dielectric, and the signal interference between the electrode 12 and the bridge wiring 16 can be suppressed as in the case of the hollow 50.

  The second embodiment is an example in which the support portion is formed by a method different from the first embodiment.

  6 and 7 are diagrams illustrating a method of manufacturing a semiconductor laser according to the second embodiment. In this embodiment, a Fabry-Perot (FP) type laser having a pn buried heterostructure (pnBH: pn-Buried Heterostructure) will be described as an example. First, as shown in FIG. 6A, a lower clad layer 32, an active layer 34, an upper clad layer 36, and a stripe mask 39 are sequentially formed on a substrate 30. As the substrate 30, for example, an n-InP substrate can be used, and the surface is a (100) plane. For example, an n-InP cladding layer having a thickness of 0.3 μm can be used for the lower cladding layer 32, and a p-InP cladding layer having a thickness of 0.2 μm can be used for the upper cladding layer 36, respectively. Here, the thickness of the upper clad layer 36 is set to be smaller (thinner) than that of the first embodiment. Further, unlike the first embodiment, the contact layer is not formed at this stage.

The active layer 34 has the MQW structure including the SCH layer as in the first embodiment, and the material is, for example, InGaAsP, and the thickness can be, for example, 0.3 μm. The stripe mask 39 is formed on the upper clad layer 36 so as to extend in the <011> direction. For the stripe mask 39, for example, SiO ₂ can be used.

  Next, as shown in FIG. 6B, using the stripe mask 39 as a mask, the upper clad layer 36, the active layer 34, the lower clad layer 32, and a part of the substrate 30 are dry-etched to obtain the stripe-shaped mesa 10. Form. The height of the striped mesa 10 can be set to 2 μm, for example.

  Next, as illustrated in FIG. 6C, the first block layer 60, the second block layer 62, and the third block layer 64 serving as the support portions are grown in order on both sides of the striped mesa 10. The surface of the first block layer 60 is located below the upper surface of the striped mesa 10 (the surface of the upper cladding layer 36). As the first block layer 60, for example, a p-InP block layer can be used, and the thickness thereof can be set to 1.0 μm, for example. The surfaces of the second block layer 62 and the third block layer 64 are located above the upper surface of the striped mesa 10. For example, an n-InP block layer can be used as the second block layer, and the thickness thereof can be set to 2.0 μm, for example. As the third block layer, for example, a p-InP block layer can be used, and the thickness thereof can be set to 0.5 μm, for example. The side surfaces of the second block layer 62, which is an n-InP layer, and the third block layer 64 thereabove have a tapered shape that inclines toward the electrode 12, like the side surface of the buried layer 40 in the first embodiment.

  Next, as shown in FIG. 7A, the stripe mask 39 is removed, and an additional cladding layer 70 is formed on the upper surfaces of the third block layer 64 and the striped mesa 10 (upper cladding layer 36). A contact layer 72 is formed thereon. As the additional cladding layer 70, for example, a p-InP cladding layer having a thickness of 2.0 μm can be used. For example, the contact layer 72 may have a structure in which a p-InGaAsP intermediate layer having a thickness of 0.2 μm and a p-InGaAs contact layer having a thickness of 0.5 μm are sequentially stacked from the substrate 30 side. Through the steps so far, the recesses 74 corresponding to the side surface shapes of the first block layer 60 to the third block layer 64 are formed on the surface of the contact layer 72 in the upper part of the striped mesa 10. The step of the recess is 2.0 μm, for example.

  As shown in FIG. 7B, the electrode 12, the passivation film 44, and the bridge wiring 16 are formed on the contact layer 72. Since these methods can be used in the same manner as in Example 1, detailed description thereof is omitted here.

  According to the semiconductor laser according to the second embodiment, as in the first embodiment, the support portions are formed on both sides of the striped mesa 10 and the bridge wires 16 are formed on the support portions. It can be formed apart from the electrode 12. In Example 2, the first block layer 60, the second block layer 62, the third block layer 64, the additional cladding layer 70, and the contact layer 72 are all examples of support portions. Further, according to the semiconductor laser according to the second embodiment, the step is formed using the first block layer 60, the second block layer 62, and the third block layer 64, and therefore, the halogen-based gas as in the first embodiment. Even without using the step, the step can be formed. In addition, as long as the said support part is the structure which can be spaced apart from the electrode 12 by supporting the bridge wiring 16, forms other than having shown in Examples 1-2 may be sufficient. However, it is preferable to use a semiconductor as the support portion.

  In the first and second embodiments, a Fabry-Perot (FP) type semiconductor laser has been described as an example. However, the configurations according to the first and second embodiments may be applied to other types of semiconductor lasers (for example, distributed feedback (DFB: (Distributed-Feedback) type semiconductor laser). In the case of a DFB laser, a diffraction grating is formed on the substrate 30 before forming the lower cladding layer 32 on the substrate 30. The process after the formation of the diffraction grating is the same as the process described in Examples 1-2.

  Example 3 is an example of a semiconductor laser provided with a modulator.

  FIG. 8 is a top view of the semiconductor laser according to the third embodiment. The semiconductor laser includes a laser unit 80 that performs laser oscillation and a modulation unit 90 that performs laser modulation. The laser unit 80 and the modulation unit 90 are separated by a separation unit 81.

  The laser unit 80 includes striped mesas 82a to 82d including a plurality of striped active layers (not shown) arranged in parallel, a plurality of electrodes 84a to 84d and electrodes 84a formed on the striped active layers. To 84d, a plurality of electrode pads 86a to 86d and bridge wires 88a to 88d connecting the electrodes 84a to 84d and the electrode pads 86a to 86d. Similarly, the modulation unit 90 includes striped mesas 92a to 92d including striped optical waveguides (not shown), electrodes 94a to 94d, electrode pads 96a to 96d, and bridge wirings 98a to 98d. A first end face film 89 is formed on the end face on the laser unit 80 side, and a second end face film 99 is formed on the end face on the modulation section 90 side. Both the first end face film 89 and the second end face film 99 can have a film thickness of 0.4 μm and a reflectance of 0.1%, for example.

  In the present embodiment, as in the first embodiment, the interval d1 between the striped mesas is set to 15 μm. At this time, the chip size of the semiconductor laser is 330 μm × 550 μm (L1 = 330 μm, L2 = 550 μm), and the length of L1 is smaller than that of the comparative example.

  FIG. 9 is a cross-sectional view taken along the line AA in FIG. As shown in FIG. 9, in the laser unit 80, a lower cladding layer 32, an active layer 34, an upper cladding layer 36, and a contact layer 38 are sequentially formed on a substrate 30. The modulation unit 90 includes an optical waveguide 35 that is optically coupled to the active layer 34 a of the laser unit 80. The active layer 34 and the optical waveguide 35 are each formed in a stripe shape. A diffraction grating 48 is formed at the boundary between the substrate 30 and the lower cladding layer 32 in the laser unit 80. On the contact layer 38, an electrode 84 a is formed on the laser unit 80 and an electrode 94 a is formed on the modulation unit 90. A passivation film 44 is formed on the end portions of the electrodes 84a and 94a on the upper surface of the contact layer 38, and bridge wirings 88a and 98a are led out from parts of the electrodes 84a and 94a, respectively. A back electrode 46 is formed on the back surface of the substrate 30. The thickness of the back electrode 46 can be set to 3 μm, for example, and the thickness of the passivation film 44 can be set to 0.6 μm, for example.

  As in the third embodiment, the configuration described in the first and second embodiments can also be adopted in a semiconductor laser including a modulator. As a result, the electrode pads 86a to 86d and 96a to 96d are collectively formed outside the regions of the striped mesas 82a to 82d and 92a to 92d using the bridge wirings 88a to 88d and 98a to 98d as shown in FIG. The stripe-shaped active layers (stripe-shaped mesas) can be arranged with high density.

  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims. It can be changed.

DESCRIPTION OF SYMBOLS 10 Striped mesa 12 Electrode 14 Electrode pad 16 Bridge wiring 20 1st end surface film 22 2nd end surface film 30 Substrate 32 Lower clad layer 34 Active layer 35 Optical waveguide 36 Upper clad layer 38 Contact layer 40 Embedded layer 44 Passivation film 46 Back surface Electrode 48 Diffraction grating 50 Hollow 60 First block layer 62 Second block layer 64 Third block layer 70 Additional cladding layer 72 Contact layer 80 Laser part 81 Separating part 82 Striped mesa (laser part)
84 electrode (laser part)
86 Electrode pad (laser part)
88 Bridge wiring (laser part)
90 Modulator 92 Striped mesa (Modulator)
94 electrodes (modulation section)
96 electrode pads (modulation unit)
98 Bridge wiring (modulation unit)

Claims (12)

A plurality of active layers provided in stripes apart from each other;
In correspondence with each of the active layers, a plurality of electrodes provided on the upper side of the active layer,
A support made of a semiconductor, provided in each region between the active layers, and having an upper surface located at a position higher than the electrode;
A wiring that is electrically connected to one of the plurality of electrodes, is supported by the plurality of support portions, and has a structure spaced from the electrodes positioned between the plurality of support portions;
A semiconductor laser comprising:   2. The apparatus according to claim 1, further comprising a plurality of electrode pads formed in a region different from the region where the plurality of active layers are formed and electrically connected to any one of the plurality of electrodes via the wiring. The semiconductor laser described in 1.   3. The semiconductor laser according to claim 1, wherein a side surface of the support portion has a tapered shape inclined from the upper surface of the support portion toward the electrode.   4. The semiconductor laser according to claim 1, wherein an interval between the plurality of active layers is 20 μm or less. 5. A substrate on which the plurality of active layers are formed;
The surface of the substrate is a (100) plane, and at least a part of the side surface of the support portion has a (111) B plane. Semiconductor laser.   6. The semiconductor laser according to claim 1, wherein a space between the electrode and the wiring formed on the electrode is hollow.   7. The low dielectric material having a dielectric constant of 4.0 or less is filled between the electrode and the wiring formed on the electrode. The semiconductor laser according to item. Forming a plurality of striped mesas including an active layer on a substrate;
Forming an electrode on the upper side of the striped mesa corresponding to each of the striped mesa;
A step of forming a support portion so that an upper surface is formed at a position higher than the electrode in a region between the stripe-shaped mesas made of a semiconductor;
Forming a wiring electrically connected to one of the plurality of electrodes, supported by the plurality of support portions, and having a structure separated from the electrodes positioned between the plurality of support portions; ,
A method for manufacturing a semiconductor laser, comprising: The step of forming the wiring includes
Forming a resist on top of the electrode;
Forming a wiring so as to extend above the support and the resist formed in a region between the striped mesas;
Removing the resist;
The method of manufacturing a semiconductor laser according to claim 8, comprising: The step of forming the wiring includes
Forming a low dielectric layer having a dielectric constant of 4 or less on the electrode;
Forming a wiring so as to extend above the support and the low dielectric layer formed in a region between the striped mesas;
The method of manufacturing a semiconductor laser according to claim 8, comprising:   11. The method of manufacturing a semiconductor laser according to claim 8, wherein a surface of the substrate is a (100) plane, and a side surface of the striped mesa is a (011) plane.   12. The method of manufacturing a semiconductor laser according to claim 8, wherein the step of forming the support portion includes a step of adding a halogen-based gas in addition to the source gas of the support portion.

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