Semiconductor laser, semiconductor laser device, and method for manufacturing semiconductor laser

Abstract

A semiconductor laser (100) is provided with a ridge (5) formed on an n-type semiconductor substrate (1), and an embedded layer (25) embedded so as to cover both sides in an x direction perpendicular to a y direction, which is the direction in which the ridge extends. The semiconductor laser (100) is provided with a p-type second cladding layer (9), a p-type contact layer (10), a surface-side electrode (12) connected to the p-type contact layer, and a semi-insulating layer (11) formed on the outer edge away from the ridge in the x-direction on the positive side in the z-direction, which is the direction in which the ridge protrudes, and on the positive side in the z-direction of the embedded layer, and a p-type second cladding layer (9), a p-type contact layer (10), a surface-side electrode (12) connected to the p-type contact layer, and a semi-insulating layer (11) formed on the outer edge away from the ridge in the x-direction are formed on the positive side in the z-direction on the side of the x-direction ends (29a, 29b). A semi-insulating layer or a surface-side electrode is formed.

Description

Technical Field

[0001] The present application relates to a semiconductor laser, a semiconductor laser device, and a method for manufacturing a semiconductor laser. Background Art

[0002] Semiconductor lasers are widely used as light sources for optical communications, and have high requirements for small size, high-speed operation, efficiency, and low power consumption. Patent document 1 discloses a semiconductor laser with an embedded heterostructure. The semiconductor laser of patent document 1 comprises: an n-type semiconductor substrate, an n-type cladding layer, an active layer, a ridge of a p-type cladding layer, a buried region in which the ridge is buried, a pair of grooves formed in the buried region, a p-type cladding layer stacked on the ridge and the buried region, a contact layer, an anode electrode connected to the contact layer, a cathode electrode formed on the back of the n-type semiconductor substrate, and an insulating film covering the contact layer and the groove except for the region directly above the ridge. Insulating films such as silicon oxide (SiO2) can effectively inject current from the anode electrode to the active layer.

[0003] In addition, it is important to reduce the resistance of the injection current path in order to improve the characteristics of the semiconductor laser. The resistance of the injection current path is appropriately expressed as the injection resistance. In particular, the operating current of the semiconductor laser for high-output purposes is also large, and the heat caused by the injection resistance is large, and the characteristics are significantly reduced. Therefore, it is very important to effectively dissipate the heat generated during operation.

[0004] In order to effectively dissipate the heat generated when the semiconductor laser is in operation, there is a case where the semiconductor laser is mounted so that the pn junction and the heat sink are opposed to each other, which is called bottom-junction mounting. Patent document 2 discloses a semiconductor laser device in which a semiconductor laser is mounted on a heat sink in a bottom-junction manner.

[0005] In addition, in order to effectively dissipate the heat generated when the semiconductor laser is in operation to the heat sink, the semiconductor laser device of Patent Document 2 has a cladding layer, a contact layer, and an electrode metal stacked in sequence on a waveguide layer including an active layer, and a recess (groove) penetrating the contact layer to the vicinity of the active layer is formed in the cladding layer, and a heat transfer material is filled between the recess (groove) and the heat sink. The semiconductor laser device of Patent Document 2 improves the thermal conductivity of the heat dissipation path to the heat sink and improves the heat dissipation by arranging a heat transfer material with high thermal conductivity near the active layer that becomes a heat source.

[0006] Patent Document 1: Japanese Patent Application Publication No. 2011-216680 ( Figure 1 )

[0007] Patent Document 2: Japanese Patent Application Publication No. 2001-94210 ( Figure 1 , Figure 8 )

[0008] The semiconductor laser device of Patent Document 2 has a thick cladding layer formed on the upper part of the waveguide layer including the active layer, and the resistance of the injection current path is larger than that of the semiconductor laser of Patent Document 1. In order to reduce the resistance of the injection current path and suppress the leakage current that does not contribute to laser oscillation, a semiconductor laser having an embedded structure such as the semiconductor laser of Patent Document 1 is generally used. When the semiconductor laser of Patent Document 1 is mounted on a heat sink in the following bonding method, there is an insulating film covering the contact layer and the groove except the area directly above the ridge of the active layer, so the thermal resistance of the heat dissipation path to the heat sink is increased by the insulating film with low thermal conductivity.

[0009] When the semiconductor laser of Patent Document 1 is mounted on a heat sink in a bottom-bonding manner, there is a problem that the heat dissipation of the semiconductor laser is insufficient because the thermal resistance of the heat dissipation path increases. Summary of the invention

[0010] The purpose of the technology disclosed in this specification is to suppress leakage current that does not contribute to laser oscillation and achieve excellent heat dissipation when the following combination method is mounted on a heat sink.

[0011] The semiconductor laser of an example disclosed in the specification of the present application comprises: a ridge formed on an n-type semiconductor substrate, and a buried layer buried in a manner of covering both sides opposite to each other in a direction perpendicular to the extension direction of the ridge, and the semiconductor laser is mounted on the surface of the side protruding from the ridge. The direction in which the ridge protrudes from the surface side of the n-type semiconductor substrate is set as the z direction, the extension direction of the ridge is set as the y direction, and the direction perpendicular to the z direction and the y direction is set as the x direction. The ridge has: an n-type cladding layer, an active layer, and a p-type first cladding layer formed in sequence from the n-type semiconductor substrate side. The buried layer has: a p-type first buried layer, a second buried layer, and an n-type third buried layer that are in contact with the side surface of the ridge on the positive side in the x direction and the side surface on the negative side in the x direction. The semiconductor laser comprises: a p-type second cladding layer, a p-type contact layer, a surface-side electrode connected to the p-type contact layer, and a semi-insulating layer formed at the outer edge away from the ridge portion along the x-direction on the positive side of the ridge in the z-direction and on the positive side of the n-type third buried layer in the z-direction, and a semi-insulating layer or a surface-side electrode are formed on the positive side in the z-direction of the end side in the x-direction of the semiconductor laser.

[0012] Effects of the Invention

[0013] A semiconductor laser as an example disclosed in the present application specification has a semi-insulating layer that is separated from a ridge having an active layer along the x direction and is provided at the outer edge on the side opposite to the n-type semiconductor substrate. Therefore, when mounted from the surface electrode side, leakage current that does not contribute to laser oscillation can be suppressed and excellent heat dissipation can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a diagram showing a cross-sectional structure of a first semiconductor laser according to Embodiment 1.

[0015] Figure 2 It is a diagram showing a cross-sectional structure of a semiconductor laser device according to Embodiment 1.

[0016] Figure 3 It is a diagram showing a cross-sectional structure of a second semiconductor laser according to the first embodiment.

[0017] Figure 4 Yes means Figure 1 FIG. 1 is a diagram of a method for manufacturing a semiconductor laser.

[0018] Figure 5 Yes means Figure 1 FIG. 1 is a diagram of a method for manufacturing a semiconductor laser.

[0019] Figure 6 Yes means Figure 1 FIG. 1 is a diagram of a method for manufacturing a semiconductor laser.

[0020] Figure 7 Yes means Figure 1 FIG. 1 is a diagram of a method for manufacturing a semiconductor laser.

[0021] Figure 8 Yes means Figure 1 FIG. 1 is a diagram of a method for manufacturing a semiconductor laser.

[0022] Fig. 9 Yes means Figure 1 FIG. 1 is a diagram of a method for manufacturing a semiconductor laser.

[0023] Fig.10 It is a diagram showing a cross-sectional structure of a semiconductor laser according to a comparative example.

[0024] Fig.11 It is a diagram showing a cross-sectional structure of a semiconductor laser device according to a comparative example.

[0025] Fig.12 It is a diagram showing a cross-sectional structure of a semiconductor laser according to a second embodiment.

[0026] Fig.13 It is a diagram showing a cross-sectional structure of a semiconductor laser device according to a second embodiment.

[0027] Fig.14 Yes means Fig.12 Graph of the width of a convex portion in a semiconductor laser.

[0028] Fig.15 Yes means Fig.12 FIG. 1 is a diagram of a method for manufacturing a semiconductor laser.

[0029] Fig.16 Yes means Fig.12 FIG. 1 is a diagram of a method for manufacturing a semiconductor laser.

[0030] Fig.17 Yes means Fig.12 FIG. 1 is a diagram of a method for manufacturing a semiconductor laser.

[0031] Fig.18 Yes means Fig.12 FIG. 1 is a diagram of a method for manufacturing a semiconductor laser.

[0032] Fig.19 Yes means Fig.12 FIG. 1 is a diagram of a method for manufacturing a semiconductor laser.

[0033] Fig. 20 It is a diagram showing a cross-sectional structure of a semiconductor laser according to a third embodiment.

[0034] Fig.21 It is a diagram showing a cross-sectional structure of a semiconductor laser device according to a third embodiment.

[0035] Fig. 22 Yes means Fig. 20 FIG. 1 is a diagram of a method for manufacturing a semiconductor laser.

[0036] Fig.23 Yes means Fig. 20 FIG. 1 is a diagram of a method for manufacturing a semiconductor laser.

[0037] Fig.24 Yes means Fig. 20 FIG. 1 is a diagram of a method for manufacturing a semiconductor laser.

[0038] Fig.25 It is a diagram showing a cross-sectional structure of a first semiconductor laser according to a fourth embodiment.

[0039] Fig.26 It is a diagram showing a cross-sectional structure of a first semiconductor laser device according to a fourth embodiment.

[0040] Fig. 27 It is a diagram showing a cross-sectional structure of a second semiconductor laser according to a fourth embodiment.

[0041] Fig.28It is a diagram showing a cross-sectional structure of a second semiconductor laser device according to a fourth embodiment.

[0042] Fig.29 It is a diagram showing a cross-sectional structure of a third semiconductor laser according to the fourth embodiment.

[0043] Fig.30 This is a diagram showing the width of a convex portion in a semiconductor laser according to a fourth embodiment.

[0044] Fig.31 Yes means Fig.25 FIG. 1 is a diagram of a method for manufacturing a semiconductor laser.

[0045] Fig.32 Yes means Fig.25 FIG. 1 is a diagram of a method for manufacturing a semiconductor laser.

[0046] Fig.33 Yes means Fig.25 FIG. 1 is a diagram of a method for manufacturing a semiconductor laser.

[0047] Fig.34 Yes means Fig.25 FIG. 1 is a diagram of a method for manufacturing a semiconductor laser.

[0048] Fig.35 It is a diagram showing a cross-sectional structure of a first semiconductor laser according to a fifth embodiment.

[0049] Fig.36 It is a diagram showing a cross-sectional structure of a first semiconductor laser device according to a fifth embodiment.

[0050] Fig.37 It is a diagram showing a cross-sectional structure of a second semiconductor laser according to the fifth embodiment.

[0051] Fig.38 It is a diagram showing a cross-sectional structure of a second semiconductor laser device according to the fifth embodiment.

[0052] Fig.39 It is a diagram showing a cross-sectional structure of a third semiconductor laser according to the fifth embodiment.

[0053] Fig.40 Yes means Fig.35 FIG. 1 is a diagram of a method for manufacturing a semiconductor laser. DETAILED DESCRIPTION

[0054] Implementation method 1.

[0055] Figure 1 is a diagram showing a cross-sectional structure of a first semiconductor laser according to Embodiment 1, Figure 2 It is a diagram showing a cross-sectional structure of a semiconductor laser device according to Embodiment 1. Figure 3It is a diagram showing a cross-sectional structure of a second semiconductor laser according to the first embodiment. Figures 4 to 9 Yes means Figure 1 FIG. 1 is a diagram of a method for manufacturing a semiconductor laser. Fig.10 is a diagram showing a cross-sectional structure of a semiconductor laser of a comparative example, Fig.11 1 is a diagram showing a cross-sectional structure of a semiconductor laser device of a comparative example. The semiconductor laser 100 of the first embodiment includes a ridge 5 formed on an n-type semiconductor substrate 1 which is an n-type InP substrate, and a buried layer 25 buried so as to cover both sides facing each other in a direction perpendicular to the extending direction of the ridge 5. The direction in which the ridge 5 protrudes from the surface side of the n-type semiconductor substrate 1 is defined as the z direction, the extending direction in which the ridge 5 extends is defined as the y direction, and the direction perpendicular to the z direction and the y direction is defined as the x direction. Figure 1 The semiconductor laser 100 shown in the figure shows an example in which the ridge 5 protrudes from the surface side of the n-type semiconductor substrate 1 to the positive side in the z direction, the end on the positive side in the x direction indicated by the dotted line 51a is the x-direction end 29b, and the end on the negative side in the x direction indicated by the dotted line 51d is the x-direction end 29a. The ridge 5 is formed between the dotted line 41a and the dotted line 41b, and the ridge 50 is formed between the dotted line 43a and the dotted line 43b. In addition, the positive side in the z direction is appropriately expressed as the surface side, and the negative side in the z direction is appropriately expressed as the back side.

[0056] The semiconductor laser 100 comprises: a ridge 5 having an n-type cladding layer 2, an active layer 3, and a p-type first cladding layer 4 formed in sequence from an n-type semiconductor substrate 1 side; a buried layer 25 having a p-type first buried layer 6, a second buried layer 7, and an n-type third buried layer 8 in contact with the side surface on the positive side in the x direction and the side surface on the negative side in the x direction of the ridge 5; a p-type second cladding layer 9 and a p-type contact layer 10 formed in sequence from the n-type semiconductor substrate 1 side on the positive side in the z direction of the ridge 5 and on the positive side in the z direction of the n-type third buried layer 8; an anode electrode 12 being a surface side electrode connected to the p-type contact layer 10; a semi-insulating layer 11 formed on the outer edge of a ridge portion 50 which is away from the ridge 5 and the p-type first buried layer 6 in contact with both side surfaces of the ridge 5 in the x direction; and a cathode electrode 13 being a back electrode formed on the back surface of the n-type semiconductor substrate 1. The semi-insulating layer 11 and the anode electrode 12 are formed on the positive side in the z direction of the x-direction end portions 29a and 29b of the semiconductor laser 100. The semi-insulating layer 11 is formed in the end region 24 from the dotted line 51a to the dotted line 51b on the x-direction end portion 29a side of the semiconductor laser 100. Similarly, the semi-insulating layer 11 is formed in the end region 24 from the dotted line 51c to the dotted line 51d on the x-direction end portion 29b side of the semiconductor laser 100.

[0057] The semiconductor laser device 200 of the first embodiment includes a semiconductor laser 100 and a heat sink 17 . The positive side in the z direction of the semiconductor laser 100 where the anode electrode 12 is formed is connected to the heat sink 17 via a connection member 14 such as gold-tin solder. Figure 2 The semiconductor laser device 200 shown in the figure shows a cross section when it is mounted on the heat sink 17 in the following bonding method. The surface of the semiconductor laser 100 on the side protruding from the ridge 5, that is, the positive side in the z direction, is mounted on the heat sink 17 in the following bonding method.

[0058] The n-type semiconductor substrate 1 is an InP substrate, for example, an n-type InP substrate doped with sulfur (S). The n-type cladding layer 2 is, for example, a cladding layer of n-type InP doped with sulfur. The active layer 3 includes a plurality of quantum wells of AlGaInAS or InGaASP materials. The p-type first cladding layer 4 is, for example, a cladding layer of p-type InP doped with zinc (Zn). The ridge 5 has a stripe shape extending in the y direction.

[0059] The ridge 5 is formed by etching the n-type cladding layer 2 , the active layer 3 , and the p-type first cladding layer 4 formed in sequence on the n-type semiconductor substrate 1 to a position lower than the active layer 3 , that is, lower than the negative side of the active layer 3 in the z direction. Figure 1 The first semiconductor laser 100 shown is an example in which the ridge etching position 52 reaches the n-type semiconductor substrate 1. Figure 3 The second semiconductor laser 100 shown is an example in which the ridge etching position 52 is arranged in the n-type cladding layer 2. The ridge 5 is buried at a position higher than the active layer 3, that is, at the positive side of the active layer 3 in the z direction, that is, at the active layer surface position 44 (see FIG. 1 ), through the p-type first buried layer 6, the second buried layer 7, and the n-type third buried layer 8 that are in contact with the side surface on the positive side in the x direction and the side surface on the negative side in the x direction (see FIG. 1 ). Figure 6 The p-type first buried layer 6 is, for example, a buried layer of p-type InP doped with zinc, the second buried layer 7 is a semi-insulating buried layer of InP doped with iron (Fe) as a semi-insulating material, and the n-type third buried layer 8 is, for example, a buried layer of n-type InP doped with sulfur.

[0060] Figure 1 The first semiconductor laser 100 shown is an example in which the second buried layer 7 is formed to the positive side of the ridge 5 in the z direction. Figure 3The second semiconductor laser 100 shown is an example in which the second buried layer 7 is formed to the active layer surface position 44. The second buried layer 7 may also be a semi-insulating buried layer of InP doped with materials such as titanium (Ti), cobalt (Co), and rubidium (Ru). In addition, the p-type first buried layer 6 and the second buried layer 7 are formed by a combination of other semiconductor layers having different impurity concentrations or conductivity types. An n-type third buried layer 8 is formed on the surface of the second buried layer 7. A p-type second cladding layer 9 is formed on the positive side of the n-type third buried layer 8 and the ridge 5 in the z direction. A p-type contact layer 10 is formed on the positive side of the p-type second cladding layer 9 in the z direction, and a semi-insulating layer 11 is formed on the positive side of the p-type contact layer 10 in the z direction and in the end region 24. An anode electrode 12 is formed in a manner covering the surface of the semi-insulating layer 11 and the surface of the p-type contact layer 10 with the semi-insulating layer 11 removed, and a cathode electrode 13 is formed on the back side of the n-type semiconductor substrate 1. The opening of the semi-insulating layer 11 is arranged on the positive side in the z direction in the region including the ridge 50 of the p-type contact layer 10. The region where the opening of the semi-insulating layer 11 is arranged is a region where current flows from the anode electrode 12 to the ridge 5 via the p-type contact layer 10 and the p-type second cladding layer 9. Figure 1 The first semiconductor laser 100 shown is an example in which the n-type third buried layer 8 is formed at a position farther from the n-type semiconductor substrate 1 than the positive side of the ridge 5 in the z direction. Figure 3 The second semiconductor laser 100 shown is an example in which the n-type third buried layer 8 is formed on the n-type semiconductor substrate 1 side relative to the positive side of the ridge 5 in the z direction. Figure 1 , Figure 3 , an example is shown in which the anode electrode 12 covers the entire front side of the semiconductor laser 100 in the z direction.

[0061] The p-type second cladding layer 9 is, for example, a cladding layer of p-type InP doped with zinc. The p-type contact layer 10 is, for example, a contact layer of p-type InGaAS doped with zinc. The semi-insulating layer 11 is, for example, a semi-insulating layer of InP doped with iron. The semi-insulating layer 11 may also be a semi-insulating layer of InP doped with materials such as titanium, cobalt, and rubidium. The materials of the anode electrode 12 and the cathode electrode 13 are metals such as gold (Au), germanium (Ge), zinc, platinum (Pt), and titanium. When the connecting component 14 is a gold-tin solder when the semiconductor laser 100 is mounted in the following combination, in order to prevent gold from diffusing into the semiconductor layer on the side of the n-type semiconductor substrate 1 that is closer to the p-type contact layer 10 and the p-type contact layer 10, a barrier metal such as platinum may be sandwiched between the p-type contact layer 10 and the anode electrode 12.

[0062] Next, use Figures 4 to 9 The example shown here will be used to explain a method for manufacturing the semiconductor laser 100 according to the first embodiment. Figures 4 to 9In the present invention, a method for manufacturing the first semiconductor laser 100 is shown, but a method for manufacturing the second semiconductor laser 100 is also included in the description. Figure 4 The ridge forming step of forming the ridge 5 is shown. In the ridge forming step, the n-type cladding layer 2, the active layer 3, and the p-type first cladding layer 4 are sequentially formed on the n-type semiconductor substrate 1, and a first mask 31 of SiO2, SiN, etc. is formed with the width of the ridge 5 in the x direction. Next, the first mask 31 is used to etch to a position lower than the n-type semiconductor substrate 1 side of the active layer 3, that is, the negative side in the z direction, to form a ridge 5 having the n-type cladding layer 2, the active layer 3, and the p-type first cladding layer 4 with the side surface on the positive side in the x direction and the side surface on the negative side in the x direction exposed. The ridge etching position 52 when forming the ridge 5 is a position lower than the negative side of the active layer 3 in the z direction.

[0063] Figure 5 , Figure 6 The figure shows a burying process of burying the ridge 5 by the burying layer 25. In the burying process, a first mask 31 is used to form a p-type first buried layer 6 on the side surface of the ridge 5 on the positive side in the x direction and the side surface on the negative side in the x direction, that is, both side surfaces, and the ridge 5 is buried to a position higher than the positive side position of the active layer 3 in the z direction, that is, the active layer surface position 44, by the second buried layer 7 and the n-type third buried layer 8 formed in sequence. Figure 1 The first semiconductor laser 100 shown, Figure 3 The second semiconductor laser 100 shown is an example in which the second buried layer 7 is formed to a position higher than the active layer surface position 44 .

[0064] Figure 7 , Figure 8 FIG. 2 shows a lamination process of laminating a semiconductor layer on the surface of the ridge 5 and the buried layer 25. Figure 7 As shown, as a pre-treatment of the stacking process, the first mask 31 is removed using buffered hydrofluoric acid or hydrofluoric acid. Then, in the stacking process, the p-type second cladding layer 9, the p-type contact layer 10, and the semi-insulating layer 11 are sequentially formed on the positive side of the ridge 5 in the z direction and the positive side of the n-type third buried layer 8 in the z direction.

[0065] Fig. 9 The contact layer exposing step of exposing the p-type contact layer 10 is shown. In the contact layer exposing step, a resist mask 32 having an opening in the x direction of the ridge portion 50 including the ridge 5 and the p-type first buried layer 6 in contact with both side surfaces of the ridge 5 is formed, and then the semi-insulating layer 11 is selectively etched with hydrochloric acid using the resist mask 32 to expose the p-type contact layer 10. Then, the resist mask 32 is removed.

[0066] Next, if Figure 1 , Figure 3As shown, a surface electrode forming step of forming an anode electrode 12 as a surface electrode on the exposed p-type contact layer 10 and the semi-insulating layer 11 on the positive side in the z direction and the side surface on the ridge 50 side, and a back side electrode forming step of forming a cathode electrode 13 as a back side electrode on the back side of the n-type semiconductor substrate 1, that is, the negative side in the z direction, are performed. Through the above steps, the semiconductor laser 100 of the first embodiment is manufactured.

[0067] Fig.10 , Fig.11 A semiconductor laser 110 and a semiconductor laser device 210 of a comparative example are shown. The semiconductor laser 110 of the comparative example is different from the first semiconductor laser 100 of the first embodiment in that an insulating film 28 of SiO 2 is formed on the p-type contact layer 10 instead of the semi-insulating layer 11 .

[0068] The operation of the semiconductor laser 100 and the semiconductor laser device 200 of the first embodiment is described. During operation, a forward bias is applied between the anode electrode 12 and the cathode electrode 13 of the semiconductor laser 100. In the semiconductor laser device 200 of the first embodiment, a forward bias is applied between the anode electrode 12 and the cathode electrode 13 of the semiconductor laser 100 via the heat sink 17. By applying a forward bias between the anode electrode 12 and the cathode electrode 13, a current is injected from the anode electrode 12 into the p-type contact layer 10 including the ridge 50 and the semi-insulating layer opening region where the semi-insulating layer 11 is removed. The semi-insulating layer opening region is a current injection region. The injected current passes through the second buried layer 7 and the n-type third buried layer 8 to narrow the ridge 5 into a stripe-shaped region and is input to the ridge 5. By the current injected into the active layer 3, a laser having a wavelength corresponding to the band gap energy of the semiconductor layer constituting the active layer 3 is generated and emitted to the outside of the semiconductor laser 100. The laser is emitted along the y direction where the ridge 5 extends.

[0069] The main source of heat generation in the semiconductor laser 100 is the active layer 3. The heat generated in the active layer 3 is conducted to the surrounding semiconductor layers and spreads to the outside of the active layer 3. In the semiconductor laser 110 and the semiconductor laser device 210 of the comparative example, the heat generated in the active layer 3 is conducted from the active layer 3 to the surrounding semiconductor layers, namely, the p-type first buried layer 6, the second buried layer 7, the n-type third buried layer 8, the p-type second cladding layer 9, and the p-type contact layer 10. In the semiconductor laser 110 and the semiconductor laser device 210 of the comparative example, the current injection region is an insulating film opening region where the insulating film 28 is removed. In the current injection region, heat is conducted from the p-type contact layer 10 to the anode electrode 12. However, in the outer region outside the current injection region where the insulating film 28 is located, that is, the outer region, the heat is conducted from the p-type contact layer 10 to the anode electrode 12 via the insulating film 28. Then, the heat is dissipated from the anode electrode 12 to the heat sink 17 via the connecting member 14. In order to suppress leakage current outside the active layer 3, the semiconductor laser 110 of the comparative example covers the p-type contact layer 10 with an insulating film 28 outside the current injection region including the ridge 5 having the active layer 3. The thermal conductivity of SiO2 used as the insulating film 28 is 1.38W / (m·K). Compared with InP, which has a thermal conductivity of 70W / (m·K), SiO2 has poor thermal conductivity. Therefore, the semiconductor laser device in which the semiconductor laser 110 of the comparative example is mounted in the following combination, that is, the semiconductor laser device 210 of the comparative example has insufficient heat dissipation from the surface area of ​​the insulating film 28, that is, the above-mentioned outer area, and the high-temperature characteristics are reduced. The semiconductor laser device 210 of the comparative example in which the semiconductor laser 110 of the comparative example is mounted in the following combination has a large thermal resistance of the heat dissipation path, and therefore insufficient heat dissipation.

[0070] In contrast, in the semiconductor laser 100 of Embodiment 1, in the end regions 24 on the positive and negative sides of the current injection region in the x direction, not the insulating film 28, but the semi-insulating layer 11 of InP is sandwiched between the p-type contact layer 10 and the anode electrode 12, so that the thermal resistance of the heat dissipation path in the end regions 24 is lower than that of the comparative example, and the heat dissipation can be improved compared with the comparative example. The semi-insulating layer 11 is doped with iron, for example, and has semi-insulating properties, so that leakage current to the outside of the active layer 3 can be suppressed when current is injected. The semiconductor laser 100 of Embodiment 1 has the semi-insulating layer 11 in the end region 24 on the positive side of the p-type contact layer 10 in the z direction, so that leakage current to the outside of the active layer 3 that does not contribute to laser oscillation can be suppressed, and excellent heat dissipation can be achieved, and high-temperature characteristics can be improved.

[0071] In addition, the material of the semi-insulating layer 11 is not limited to InP, and a material having a thermal conductivity 10 times greater than that of SiO2 may be used. In this case, the semiconductor laser 100 of the first embodiment can also reduce the thermal resistance of the heat dissipation path compared to the comparative example, can suppress leakage current that does not contribute to laser oscillation, and achieve excellent heat dissipation.

[0072] As described above, the semiconductor laser 100 of the first embodiment is a semiconductor laser that includes a ridge 5 formed on an n-type semiconductor substrate 1 and a buried layer 25 buried to cover both sides opposed to each other in a direction perpendicular to the extension direction of the ridge 5, and is mounted on the surface of one side protruding from the ridge 5. The direction in which the ridge 5 protrudes from the surface side of the n-type semiconductor substrate 1 is set as the z direction, the extension direction in which the ridge 5 extends is set as the y direction, and the direction perpendicular to the z direction and the y direction is set as the x direction. The ridge 5 has an n-type cladding layer 2, an active layer 3, and a p-type first cladding layer 4 formed in sequence from the n-type semiconductor substrate 1 side. The buried layer 25 has a p-type first buried layer 6, a second buried layer 7, and an n-type third buried layer 8 that are in contact with the side surface of the ridge 5 on the positive side in the x direction and the side surface on the negative side in the x direction. The semiconductor laser 100 includes a p-type second cladding layer 9, a p-type contact layer 10, a surface-side electrode (anode electrode 12) connected to the p-type contact layer 10, and a semi-insulating layer 11 formed on the outer edge of the ridge portion 50 including the ridge 5 and the p-type first buried layer 6 in contact with both side surfaces of the ridge 5, which are formed in order from the n-type semiconductor substrate 1 side on the positive side of the ridge 5 in the z direction and the positive side of the n-type third buried layer 8 in the z direction. The semi-insulating layer 11 or the surface-side electrode (anode electrode 12) is formed on the positive side in the z direction on the x-direction end (x-direction end 29a, 29b) side of the semiconductor laser 100. The semiconductor laser 100 of the first embodiment has the semi-insulating layer 11 on the outer edge on the side opposite to the n-type semiconductor substrate 1 and away from the ridge portion 50 including the active layer 3 in the x direction. Therefore, when mounted from the surface-side electrode (anode electrode 12) side, it is possible to suppress leakage current that does not contribute to laser oscillation and achieve excellent heat dissipation.

[0073] In addition, the semiconductor laser device 200 of the first embodiment includes the semiconductor laser 100 of the first embodiment and the heat sink 17, and the positive side in the z direction of the semiconductor laser 100 where the surface side electrode (anode electrode 12) is formed is connected to the heat sink 17 via the connection member 14. With this configuration, the semiconductor laser device 200 of the first embodiment includes the semi-insulating layer 11 at the outer edge on the side away from the ridge portion 50 having the active layer 3 and opposite to the n-type semiconductor substrate 1 in the x direction, and the positive side in the z direction where the surface side electrode (anode electrode 12) is formed is connected to the heat sink 17 via the connection member, so that when mounted from the surface side electrode (anode electrode 12) side, it is possible to suppress leakage current that does not contribute to laser oscillation and achieve excellent heat dissipation.

[0074] In addition, the method for manufacturing a semiconductor laser of the first embodiment is a method for manufacturing a semiconductor laser 100 having a ridge 5 formed on an n-type semiconductor substrate 1 and a buried layer 25 buried to cover both sides opposite to each other in a direction perpendicular to the extension direction of the ridge 5. The method for manufacturing a semiconductor laser of the first embodiment includes a ridge forming step, a burying step, a laminating step, a contact layer exposing step, and a surface side electrode forming step described later. In the ridge forming step, an n-type cladding layer 2, an active layer 3, and a p-type first cladding layer 4 are sequentially formed on the n-type semiconductor substrate 1, and the ridge 5 having the n-type cladding layer 2, the active layer 3, and the p-type first cladding layer 4 is formed by etching to a position lower than the n-type semiconductor substrate 1 side of the active layer 3, that is, the negative side in the z direction, and the positive side side in the x direction and the negative side side in the x direction are exposed. In the embedding step, a p-type first embedded layer 6 is formed on the side surface of the ridge 5 on the positive side in the x direction and the side surface on the negative side in the x direction, and the ridge 5 is embedded to a position higher than the positive side position in the z direction of the active layer 3, that is, the active layer surface position 44, by the second embedded layer 7 and the n-type third embedded layer 8 formed in sequence. In the stacking step, a p-type second cladding layer 9, a p-type contact layer 10, and a semi-insulating layer 11 are formed in sequence on the positive side in the z direction of the ridge 5 and the positive side in the z direction of the n-type third embedded layer 8. In the contact layer exposing step, the semi-insulating layer 11 in the x-direction region including the ridge 50 is etched to expose the p-type contact layer 10, wherein the ridge 50 includes the ridge 5 and the p-type first embedded layer 6 in contact with both side surfaces of the ridge 5. In the surface side electrode forming step, a surface side electrode (anode electrode 12) is formed on the positive side in the z direction of the exposed p-type contact layer 10 and the semi-insulating layer 11 and the side surface on the ridge 50 side. The semiconductor laser manufacturing method of embodiment 1 can manufacture a semiconductor laser 100 with a semi-insulating layer 11 on the outer edge on the side opposite to the n-type semiconductor substrate 1 and away from the ridge 50 having the active layer 3 in the x direction through this structure. Therefore, when installed from the surface side electrode (anode electrode 12), leakage current that does not contribute to laser oscillation can be suppressed and excellent heat dissipation can be achieved.

[0075] Implementation method 2.

[0076] Fig.12 is a diagram showing a cross-sectional structure of a semiconductor laser according to Embodiment 2, Fig.13 It is a diagram showing a cross-sectional structure of a semiconductor laser device according to a second embodiment. Fig.14 Yes means Fig.12 Graph of the width of a convex portion in a semiconductor laser. Figure 15 to Figure 19 Yes means Fig.12 The semiconductor laser 100 of the second embodiment is different from the semiconductor laser 100 of the first embodiment in that two grooves 19 extending in the y direction are provided between the outer side in the x direction of the ridge 50 and the x-direction ends 29a and 29b. The following mainly describes the parts different from the semiconductor laser 100 and the semiconductor laser device 200 of the first embodiment.

[0077] The semiconductor laser 100 of the second embodiment is similar to the semiconductor laser 100 of the first embodiment, and comprises a ridge 5 formed on an n-type semiconductor substrate 1, a buried layer 25 buried to cover two sides opposite to each other in a direction perpendicular to the extension direction of the ridge 5, a p-type second cladding layer 9 formed on the positive side in the z direction of the ridge 5 and on the positive side in the z direction of the n-type third buried layer 8, a p-type contact layer 10, a semi-insulating layer 11 formed on the outer edge away from the ridge 50 in the x direction, an anode electrode 12, and a cathode electrode 13. The semiconductor laser 100 of the second embodiment further comprises two grooves 19 formed and extending in the y direction between the outer side in the x direction of the ridge 50 and the x-direction ends 29a and 29b, and an insulating film 15 formed on the inner surface of the groove 19. The material of the insulating film 15 is SiO2, SiN, or other insulating materials. Fig.12 , Fig.13 , an example is shown in which the x-direction end 29a side of the surface of the semi-insulating layer 11 on the negative side of the x-direction and the x-direction end 29b side of the semi-insulating layer 11 on the positive side of the x-direction are exposed, but the surface of the semi-insulating layer 11 may also be covered by the anode electrode 12 or a metal that is not connected to the anode electrode 12.

[0078] The groove 19 penetrates the p-type contact layer 10, the p-type second cladding layer 9, and the n-type third buried layer 8, and the bottom 22 of the groove 19 is the same as the positive side position of the active layer 3 in the second buried layer 7 in the z direction, that is, the active layer surface position 44, or the bottom 22 of the groove 19 is farther from the n-type semiconductor substrate 1 than the active layer surface position 44 in the second buried layer 7. That is, the bottom 22 of the groove 19 can be located between the active layer surface position 44 and the positive side of the second buried layer 7 in the z direction. The anode electrode 12 is connected to the p-type contact layer 10 in the convex portion 18 formed between the two grooves 19. The convex portion 18 is formed to extend in the y direction in the range from the dotted line 42a to the dotted line 42b in the x direction. The groove 19 is equivalent to a mesa transistor groove, so the convex portion 18 can also be a mesa transistor bar.

[0079] The side surface in the x direction of the groove 19 on the side away from the protrusion 18 is the groove first side surface 46, and the side surface in the x direction of the groove 19 on the side closer to the protrusion 18 than the groove first side surface 46 is the groove second side surface 47. On the side of the x-direction end 29b, the groove 19 is formed between the dotted line 42b and the dotted line 51c, and the end region 24 is formed between the dotted line 51c and the dotted line 51d. On the side of the x-direction end 29a, the groove 19 is formed between the dotted line 42a and the dotted line 51b, and the end region 24 is formed between the dotted line 51b and the dotted line 51a. The semi-insulating layer 11 is formed on the positive side in the z direction of the p-type contact layer 10 from the groove first side surface 46 of the groove 19 to the x-direction end (x-direction end 29a, 29b) on the side opposite to the protrusion 18 of the semiconductor laser 100, and is not covered by the anode electrode on the x-direction end side of the semiconductor laser 100. That is, the semi-insulating layer 11 is formed on the positive side in the z direction of the p-type contact layer 10 in the end region 24 of the x-direction end 29b.

[0080] Fig.13 The example of the semiconductor laser device 200 is shown in which the connection member 14 is filled in the groove 19, the position of the negative side of the connection member 14 in the z direction covers a part of the second buried layer 7 at the x-direction ends 29a and 29b, and the semiconductor laser 100 of the second embodiment is mounted on the heat sink 17 in the following bonding manner. The width of the convex portion 18 in the x direction, i.e., the convex portion width W2, is larger than the width of the ridge portion 50 in the x direction, i.e., the ridge portion width W1.

[0081] Next, use the above Figures 4 to 8 as well as Figure 15 to Figure 19 As an example shown, a method for manufacturing the semiconductor laser 100 according to the second embodiment will be described. Figures 4 to 8 The ridge forming process, embedding process, and lamination process shown are the same as those in Embodiment 1. Figure 8After the lamination process shown, perform Fig.15 The groove forming process shown. In the semiconductor layer formed to the semi-insulating layer 11, two grooves 19 are formed on both sides of the ridge 50 in the x direction using the resist mask 32 so that the bottom 22 is located at a position lower than the n-type third buried layer 8 and higher than the active layer 3. More specifically, in the groove forming process, the groove 19 is formed at the two outer edges away from the ridge 50 on the positive side and the negative side of the x direction, and the groove 19 penetrates the semi-insulating layer 11, the p-type contact layer 10, the p-type second cladding layer 9, and the n-type third buried layer 8, and the position of the bottom 22 in the z direction is the same as the active layer surface position 44 of the active layer 3 of the second buried layer 7 or is located on the positive side of the active layer surface position 44.

[0082] Next, a contact layer exposing step of etching the semi-insulating layer 11 of the convex portion 18 formed between the two trenches 19 to expose the p-type contact layer 10 and an insulating film forming step of forming the insulating film 15 on both side surfaces and the bottom 22 of each trench 19 in the x direction are performed. Fig.16 As shown in FIG. 1 , a resist mask 32 is formed so as to form an opening in the center of the convex portion 18 in the x direction, and the semi-insulating layer 11 of the convex portion 18 is selectively etched by hydrochloric acid. Fig.16 2 shows an example in which the width of the opening of the resist mask 32 in the x direction is smaller than that of the protrusion 18 .

[0083] Next, the insulating film 15 is formed into a final shape. Fig.19 The insulating film 15 is shaped as shown. Fig.17 After the resist mask 32 is removed in this manner, an insulating film 15 is formed on the surface of the exposed semiconductor layer and the inner surface of the trench 19. Fig.18 In this way, a resist mask 32 is formed to cover the trench 19, as shown in FIG. Fig.19 In this way, the insulating film 15 is shaped by etching. Then, the resist mask 32 is removed. Fig.18 2 shows an example in which the width of the resist mask 32 in the x direction is larger than the width of the trench 19 in the x direction. Fig.19 2 shows an example in which the insulating film forming step of etching the insulating film 15 to form the insulating film 15 in the final shape and the contact layer exposing step of etching the insulating film 15 of the convex portion 18 to expose the p-type contact layer 10 are simultaneously performed. Fig.16 The process shown and Fig.19 The insulating film forming step of forming the insulating film 15 on both side surfaces and the bottom 22 of the trench 19 in the x direction is performed. Figure 17 to Figure 19 The process shown.

[0084] Then, if Fig.12As shown, the following steps are performed: a surface side electrode forming step, forming an anode electrode 12 in a manner that covers the p-type contact layer 10 of the convex portion 18 that has not been formed with the insulating film 15 by the insulating film forming step; and a back side electrode forming step, forming a cathode electrode 13 on the back side of the n-type semiconductor substrate 1, that is, the negative side in the z direction. The anode electrode 12 is patterned using a resist mask. The semiconductor laser 100 of the second embodiment is manufactured through the above steps.

[0085] The semiconductor laser device 200 of embodiment 2 in which the semiconductor laser 100 of embodiment 2 is mounted in the following combination conducts the heat generated in the active layer 3 from the active layer 3 to the surrounding semiconductor layers, namely, the p-type first buried layer 6, the second buried layer 7, the n-type third buried layer 8, the p-type second cladding layer 9, and the p-type contact layer 10. In the convex portion 18, the heat from the active layer 3 is dissipated from the anode electrode 12 to the heat sink 17 via the connection member 14. In the end region 24, the heat from the active layer 3 is conducted to the semi-insulating layer 11, and is dissipated from the semi-insulating layer 11 to the heat sink 17 via the connection member 14.

[0086] The semiconductor laser 100 of the second embodiment is similar to the semiconductor laser 100 of the first embodiment, in which the semi-insulating layer 11 of InP covers the p-type contact layer 10 at the x-direction ends 29b and 29a of the end regions 24 on the positive and negative sides in the x-direction, and the insulating film 15 formed on the inner surface of the trench 19 is formed to be thinner than the p-type contact layer 10. Fig.10 The insulating film 28 of the semiconductor laser 110 of the comparative example shown is thin, so the thermal resistance of the heat dissipation path in the end region 24 is lower than that of the comparative example, and the heat dissipation can be improved compared with the comparative example, similarly to the semiconductor laser 100 of the first embodiment. The semi-insulating layer 11 has semi-insulating properties, so leakage current outside the active layer 3 can be suppressed when current is injected. The semiconductor laser 100 of the second embodiment is similar to the semiconductor laser 100 of the first embodiment, and has the semi-insulating layer 11 in the end region 24 on the positive side of the p-type contact layer 10 in the z direction, so that leakage current outside the active layer 3 that does not contribute to laser oscillation can be suppressed, and excellent heat dissipation can be achieved, and high-temperature characteristics can be improved.

[0087] In addition, the semiconductor laser 100 of the second embodiment is similar to the semiconductor laser 100 of the first embodiment, and a buried layer 25 that functions as a current blocking layer is provided on both sides of the active layer 3 in order to improve the current injection efficiency into the active layer 3. The buried layer 25 has a structure in which a semi-insulating second buried layer 7 doped with iron or the like is sandwiched by a p-type first buried layer 6 and an n-type third buried layer 8. The buried layer 25 has the same structure as a capacitor having a dielectric material sandwiched between the ends 29a and 29b in the x direction, so the buried layer 25 has a parasitic capacitance. In order to achieve high-speed operation of the semiconductor laser 100, it is effective to reduce the parasitic capacitance of the buried layer 25. The semiconductor laser 100 of the second embodiment forms the convex portion 18 to include both sides of the ridge portion 50 in the x direction, and disconnects the n-type third buried layer 8 of the buried layer 25 by using the groove 19, thereby reducing the area of ​​the n-type third buried layer 8 on the second buried layer 7 side compared with the semiconductor laser 100 of the first embodiment, and also reducing the area of ​​the n-type third buried layer 8 on the second buried layer 7 side near the active layer 3. The parasitic capacitance near the active layer 3 where the distance between the p-type first buried layer 6 and the n-type third buried layer 8 in the buried layer 25 is reduced is larger than that on the x-direction end 29a, 29b side. The semiconductor laser 100 of the second embodiment has a smaller area of ​​the n-type third buried layer 8 near the active layer 3 than the semiconductor laser 100 of the first embodiment, so the parasitic capacitance can be reduced compared with the semiconductor laser 100 of the first embodiment. That is, the semiconductor laser 100 of the second embodiment can achieve high-speed operation compared with the semiconductor laser 100 of the first embodiment.

[0088] As described above, the semiconductor laser 100 of the second embodiment is a semiconductor laser that is provided with a ridge 5 formed on an n-type semiconductor substrate 1, and a buried layer 25 buried to cover both sides opposite to each other in a direction perpendicular to the extension direction of the ridge 5, and is mounted on the surface of one side protruding from the ridge 5. The z direction, the y direction, and the x direction are as described above. The ridge 5 has an n-type cladding layer 2, an active layer 3, and a p-type first cladding layer 4 that are formed in sequence from the n-type semiconductor substrate 1 side. The buried layer 25 has a p-type first buried layer 6, a second buried layer 7, and an n-type third buried layer 8 that are in contact with the side surface of the ridge 5 on the positive side in the x direction and the side surface on the negative side in the x direction. The semiconductor laser 100 includes a p-type second cladding layer 9, a p-type contact layer 10, a surface-side electrode (anode electrode 12) connected to the p-type contact layer 10, and a semi-insulating layer 11 formed on the outer edge of the ridge 50 including the ridge 5 and the p-type first buried layer 6 in contact with both side surfaces of the ridge 5, which are formed in order from the n-type semiconductor substrate 1 side on the positive side in the z direction of the ridge 5 and the positive side in the z direction of the n-type third buried layer 8, and formed in the x direction away from the outer edge of the ridge 50 including the ridge 5 and the p-type first buried layer 6 in contact with both side surfaces of the ridge 5, and the semi-insulating layer 11 is formed on the positive side in the z direction on the side of the x direction end (x-direction end 29a, 29b) of the semiconductor laser 100. Grooves 19 extending in the y direction are provided between the side surface on the positive side in the x direction of the ridge 50 and the end on the positive side in the x direction (x-direction end 29b) of the semiconductor laser 100, and between the side surface on the negative side in the x direction of the ridge 50 and the end on the negative side in the x direction (x-direction end 29a) of the semiconductor laser 100. Each groove 19 penetrates the p-type contact layer 10, the p-type second cladding layer 9, and the n-type third buried layer 8, and the bottom 22 of the groove 19 is the same as the positive side position of the active layer 3 in the second buried layer 7 in the z direction, that is, the active layer surface position 44, or the bottom 22 of the groove 19 is farther from the n-type semiconductor substrate 1 than the active layer surface position 44 in the second buried layer 7. The surface side electrode (anode electrode 12) is connected to the p-type contact layer 10 in the convex portion 18 formed between the two grooves 19. The side surface in the x direction of the groove 19 that is farther from the convex portion 18 is set as the first side surface 46 of the groove, and the side surface in the x direction that is closer to the convex portion 18 than the first side surface 46 of the groove 19 is set as the second side surface 47 of the groove. The semi-insulating layer 11 is formed on the positive side in the z direction of the p-type contact layer 10 from the first side surface 46 of the groove 19 to the end (x-direction ends 29a, 29b) in the x direction on the side opposite to the convex portion 18 of the semiconductor laser 100. An insulating film 15 is provided on the inner surface of the groove 19. With this structure, the semiconductor laser 100 of the second embodiment has the semi-insulating layer 11 on the outer edge on the side away from the ridge 50 having the active layer 3 and opposite to the n-type semiconductor substrate 1 in the x direction. Therefore, when installed from the surface side electrode (anode electrode 12) side, it is possible to suppress leakage current that does not contribute to laser oscillation and achieve excellent heat dissipation.

[0089] In addition, the method for manufacturing a semiconductor laser of the second embodiment is a method for manufacturing a semiconductor laser 100 having a ridge 5 formed on an n-type semiconductor substrate 1 and a buried layer 25 buried to cover both sides opposite to each other in a direction perpendicular to the extension direction of the ridge 5. The method for manufacturing a semiconductor laser of the second embodiment includes a ridge forming step, a burying step, a laminating step, a groove forming step, a contact layer exposing step, an insulating film forming step, and a surface side electrode forming step described later. In the ridge forming step, an n-type cladding layer 2, an active layer 3, and a p-type first cladding layer 4 are sequentially formed on the n-type semiconductor substrate 1, and the ridge 5 having the n-type cladding layer 2, the active layer 3, and the p-type first cladding layer 4 is formed by etching to a position lower than the n-type semiconductor substrate 1 side of the active layer 3, that is, the negative side in the z direction, and the positive side side in the x direction and the negative side side in the x direction are exposed. In the embedding process, a p-type first embedding layer 6 is formed on the side surface on the positive side in the x direction and the side surface on the negative side in the x direction of the ridge 5, and the ridge 5 is embedded to a position higher than the positive side position in the z direction of the active layer 3, that is, the active layer surface position 44, by the second embedding layer 7 and the n-type third embedding layer 8 formed in sequence. In the stacking process, a p-type second cladding layer 9, a p-type contact layer 10, and a semi-insulating layer 11 are formed in sequence on the positive side in the z direction of the ridge 5 and on the positive side in the z direction of the n-type third embedding layer 8. In the groove forming step, a groove 19 is formed at two outer edges away from the ridge 50 on the positive and negative sides in the x direction, the groove 19 penetrates the semi-insulating layer 11, the p-type contact layer 10, the p-type second cladding layer 9, and the n-type third buried layer 8, and the position of the bottom 22 in the z direction is the same as the active layer surface position 44 of the active layer 3 in the second buried layer 7 or is located on the positive side of the active layer surface position 44, wherein the ridge 50 includes the ridge 5 and the p-type first buried layer 6 in contact with both side surfaces of the ridge 5. In the contact layer exposing step, the semi-insulating layer 11 of the convex portion 18 formed between the two grooves 19 is etched to expose the p-type contact layer 10. In the insulating film forming step, the insulating film 15 is formed on both side surfaces (the first trench side surface 46 and the second trench side surface 47) in the x direction and the bottom 22 of each groove 19. In the surface side electrode forming step, the surface side electrode (anode electrode 12) is formed so as to cover the p-type contact layer 10 of the convex portion 18 where the insulating film 15 is not formed in the insulating film forming step. The method for manufacturing a semiconductor laser according to the second embodiment can manufacture a semiconductor laser 100 having a semi-insulating layer 11 at the outer edge of the side away from the ridge portion 50 having the active layer 3 and opposite to the n-type semiconductor substrate 1 in the x direction, so that when mounted from the surface side electrode (anode electrode 12) side, leakage current that does not contribute to laser oscillation can be suppressed and excellent heat dissipation can be achieved.

[0090] Implementation method 3.

[0091] Fig. 20 is a diagram showing a cross-sectional structure of a semiconductor laser according to Embodiment 3, Fig.21 It is a diagram showing a cross-sectional structure of a semiconductor laser device according to a third embodiment. Figure 22 to Figure 24 Yes means Fig. 20 The semiconductor laser 100 of the third embodiment is different from the semiconductor laser 100 of the second embodiment in that the bottom 22 of the groove 19 is not covered by the insulating film 15. The following mainly describes the parts that are different from the semiconductor laser 100 and the semiconductor laser device 200 of the second embodiment. Fig. 20 , an example is shown in which the anode electrode 12 covers the insulating film 15 , the trench first side surface 46 and the trench second side surface 47 of the trench 19 , and the bottom 22 of the trench 19 .

[0092] Use the above Figures 4 to 8 , Figure 15 to Figure 19 as well as Figure 22 to Figure 24 The example shown will be used to explain a method for manufacturing the semiconductor laser 100 according to the third embodiment. Figures 4 to 8 The ridge forming process, embedding process, and lamination process shown are the same as those in the first embodiment. Figure 15 to Figure 19 The steps are the same as those of Embodiment 2. In the semiconductor laser 100 of Embodiment 3, further processing is added. Fig.19 The step of forming the insulating film 15 shown is a step of exposing the bottom of the trench. Figure 17 to Figure 19 as well as Figure 22 to Figure 24 The trench bottom exposure step is a part of the insulating film forming step. The contact layer exposure step of the third embodiment is performed in the same manner as the second embodiment. Fig.16 The process shown and Fig.19 The process shown.

[0093] The process of exposing the bottom of the groove is described below. Fig.19 The semiconductor laser 100 in the middle of manufacturing shown in the figure includes the positive side of the end region 24 in the z direction of the manufacturing intermediate, the positive side of the protrusion 18 in the z direction of the insulating film 15, and the end of the insulating film on the positive side of the z direction of the end region 24, and the positive side of the z direction of the protrusion 18, as shown in FIG. Fig. 22 A resist mask 32 is formed as shown. Figure 22 to Figure 24 An example of four insulating film ends is shown in FIG. Fig.23 As shown in FIG. 1 , the insulating film 15 at the bottom 22 of the trench 19 is etched using the resist mask 32 to expose the bottom 22 of the trench 19. Then, as shown in FIG. Fig.24 The resist mask 32 is shown removed.

[0094] Next, if Fig. 20 As shown, the following steps are performed: a surface side electrode forming step to form an anode electrode 12 in a manner that covers the p-type contact layer 10 of the protrusion 18 that has not been formed with the insulating film 15 by the insulating film forming step; and a back side electrode forming step to form a cathode electrode 13 on the back side of the n-type semiconductor substrate 1, that is, the negative side in the z direction. The anode electrode 12 is patterned using an anti-etching mask. The anode electrode 12 may also extend to an area outside the p-type contact layer 10 of the protrusion 18. As previously described, in Fig. 20 The example in which the anode electrode 12 covers the insulating film 15 of the trench first side surface 46 and the trench second side surface 47 of the trench 19 and the bottom 22 of the trench 19 is shown. The semiconductor laser 100 of the third embodiment is manufactured through the above steps.

[0095] The semiconductor laser 100 and the semiconductor laser device 200 according to the third embodiment have the same effects as those of the semiconductor laser 100 and the semiconductor laser device 200 according to the second embodiment. Fig. 20 The semiconductor laser 100 shown does not have an insulating film 15 at the bottom 22 of the groove 19, and an anode electrode 12 with high thermal conductivity is arranged in the second buried layer 7. When the metal used for the anode electrode 12 is, for example, gold, the thermal conductivity is 300 W / (m·K). By configuring the metal at the bottom 22 of the groove 19, the semiconductor laser 100 and the semiconductor laser device 200 of the third embodiment are easier to dissipate the heat generated from the active layer 3 from the positive side of the z direction of the protrusion 18, the positive side of the z direction of the end region 24, and the bottom 22 of the groove 19 compared with the semiconductor laser 100 and the semiconductor laser device 200 of the second embodiment, and the high temperature characteristics are improved. In addition, the metal at the bottom 22 of the groove 19 may not be connected to the anode electrode 12, and the metal may not be arranged at the bottom 22 of the groove 19. Even if the metal is not arranged at the bottom 22 of the groove 19, the heat is dissipated to the heat sink 17 via the connection member 14 filled in the inside of the groove 19.

[0096] As described above, the semiconductor laser 100 of the third embodiment is a semiconductor laser that is provided with a ridge 5 formed on an n-type semiconductor substrate 1, and a buried layer 25 buried to cover both sides opposite to each other in a direction perpendicular to the extension direction of the ridge 5, and is mounted on the surface of one side protruding from the ridge 5. The z direction, the y direction, and the x direction are as described above. The ridge 5 has an n-type cladding layer 2, an active layer 3, and a p-type first cladding layer 4 that are sequentially formed from the n-type semiconductor substrate 1 side. The buried layer 25 has a p-type first buried layer 6, a second buried layer 7, and an n-type third buried layer 8 that are in contact with the side surface of the ridge 5 on the positive side in the x direction and the side surface on the negative side in the x direction. The semiconductor laser 100 includes a p-type second cladding layer 9, a p-type contact layer 10, a surface-side electrode (anode electrode 12) connected to the p-type contact layer 10, and a semi-insulating layer 11 formed on the outer edge of the ridge 50 including the ridge 5 and the p-type first buried layer 6 in contact with both side surfaces of the ridge 5, which are formed in order from the n-type semiconductor substrate 1 side on the positive side in the z direction of the ridge 5 and the positive side in the z direction of the n-type third buried layer 8, and formed in the x direction away from the outer edge of the ridge 50 including the ridge 5 and the p-type first buried layer 6 in contact with both side surfaces of the ridge 5, and the semi-insulating layer 11 is formed on the positive side in the z direction on the side of the x direction end (x-direction end 29a, 29b) of the semiconductor laser 100. Grooves 19 extending in the y direction are provided between the side surface on the positive side in the x direction of the ridge 50 and the end on the positive side in the x direction (x-direction end 29b) of the semiconductor laser 100, and between the side surface on the negative side in the x direction of the ridge 50 and the end on the negative side in the x direction (x-direction end 29a) of the semiconductor laser 100. Each groove 19 penetrates the p-type contact layer 10, the p-type second cladding layer 9, and the n-type third buried layer 8, and the bottom 22 of the groove 19 is the same as the positive side position of the active layer 3 of the second buried layer 7 in the z direction, that is, the active layer surface position 44, or the bottom 22 of the groove 19 is farther from the n-type semiconductor substrate 1 than the active layer surface position 44 of the second buried layer 7. The surface side electrode (anode electrode 12) is connected to the p-type contact layer 10 in the convex portion 18 formed between the two grooves 19. The semi-insulating layer 11 is formed on the positive side of the p-type contact layer 10 in the z direction from the first side surface 46 of the groove 19 to the end (x-direction end 29a, 29b) of the semiconductor laser 100 in the x direction on the side opposite to the convex portion 18. The insulating film 15 is provided on the first side surface 46 and the second side surface 47 of the trench 19, and the surface-side electrode (anode electrode 12) covers the insulating film 15 on the first side surface 46 and the second side surface 47 of the trench and the bottom 22 of the trench 19. With this configuration, the semiconductor laser 100 of the third embodiment includes the semi-insulating layer 11 at the outer edge on the side away from the ridge portion 50 having the active layer 3 and opposite to the n-type semiconductor substrate 1 in the x direction. Therefore, when mounted from the surface-side electrode (anode electrode 12) side, leakage current that does not contribute to laser oscillation can be suppressed and excellent heat dissipation can be achieved.

[0097] In addition, the method for manufacturing a semiconductor laser of the third embodiment is a method for manufacturing a semiconductor laser 100 having a ridge 5 formed on an n-type semiconductor substrate 1 and a buried layer 25 buried to cover both sides opposite to each other in a direction perpendicular to the extension direction of the ridge 5. The method for manufacturing a semiconductor laser of the third embodiment includes a ridge forming step, a burying step, a laminating step, a groove forming step, a contact layer exposing step, an insulating film forming step, and a surface side electrode forming step described later. In the ridge forming step, an n-type cladding layer 2, an active layer 3, and a p-type first cladding layer 4 are sequentially formed on the n-type semiconductor substrate 1, and the ridge 5 having the n-type cladding layer 2, the active layer 3, and the p-type first cladding layer 4 is formed by etching to a position lower than the n-type semiconductor substrate 1 side of the active layer 3, that is, the negative side in the z direction, and the positive side side in the x direction and the negative side side in the x direction are exposed. In the embedding process, a p-type first embedding layer 6 is formed on the side surface on the positive side in the x direction and the side surface on the negative side in the x direction of the ridge 5, and the ridge 5 is embedded to a position higher than the positive side position in the z direction of the active layer 3, that is, the active layer surface position 44, by the second embedding layer 7 and the n-type third embedding layer 8 formed in sequence. In the stacking process, a p-type second cladding layer 9, a p-type contact layer 10, and a semi-insulating layer 11 are formed in sequence on the positive side in the z direction of the ridge 5 and on the positive side in the z direction of the n-type third embedding layer 8. In the groove forming step, a groove 19 is formed at two outer edges away from the ridge 50 on the positive and negative sides in the x direction, the groove 19 penetrates the semi-insulating layer 11, the p-type contact layer 10, the p-type second cladding layer 9, and the n-type third buried layer 8, and the position of the bottom 22 in the z direction is the same as the active layer surface position 44 of the active layer 3 of the second buried layer 7 or is located on the positive side of the active layer surface position 44, wherein the ridge 50 includes the ridge 5 and the p-type first buried layer 6 in contact with both side surfaces of the ridge 5. In the contact layer exposing step, the semi-insulating layer 11 of the convex portion 18 formed between the two grooves 19 is etched to expose the p-type contact layer 10. In the insulating film forming step, an insulating film 15 is formed on both side surfaces (the first side surface 46 and the second side surface 47) of each groove 19 in the x direction. In the surface side electrode forming step, the surface side electrode (anode electrode 12) is formed in a manner that covers the p-type contact layer 10 of the convex portion 18 where the insulating film 15 is not formed in the insulating film forming step, and in a manner that covers the insulating film 15 on both side surfaces (the first side surface 46 and the second side surface 47 of the groove 19) and the bottom 22 of the groove 19. The method for manufacturing a semiconductor laser of the third embodiment can manufacture a semiconductor laser 100 having a semi-insulating layer 11 at the outer edge of the side away from the ridge portion 50 having the active layer 3 and opposite to the n-type semiconductor substrate 1 in the x direction, so that when mounted from the surface side electrode (anode electrode 12) side, leakage current that does not contribute to laser oscillation can be suppressed, and excellent heat dissipation can be achieved.

[0098] Implementation method 4.

[0099] Fig.25 is a diagram showing a cross-sectional structure of a first semiconductor laser according to a fourth embodiment, Fig.26 It is a diagram showing a cross-sectional structure of a first semiconductor laser device according to a fourth embodiment. Fig. 27 is a diagram showing a cross-sectional structure of a second semiconductor laser according to a fourth embodiment, Fig.28 It is a diagram showing a cross-sectional structure of a second semiconductor laser device according to a fourth embodiment. Fig.29 It is a diagram showing a cross-sectional structure of a third semiconductor laser according to the fourth embodiment. Fig.30 This is a diagram showing the width of the convex portion of the semiconductor laser according to the fourth embodiment. Figure 31 to Figure 34 Yes means Fig.25 FIG. 1 is a diagram of a method for manufacturing a semiconductor laser. The first and third semiconductor lasers 100 of the fourth embodiment differ from the semiconductor laser 100 of the second embodiment in that the inner surface of the groove 19 is not covered by the insulating film 15 but by the semi-insulating layer 11. In addition, the second semiconductor laser 100 of the fourth embodiment differs from the semiconductor laser 100 of the second embodiment in that the groove 19 is changed to a receding portion 21 that becomes a bottom 23 until the x-direction ends 29a and 29b, and the bottom 23 of the receding portion 21 and the side surface 48 of the receding portion 21 are covered by the semi-insulating layer 11. In addition, since the bottom 23 of the receding portion 21 extends to the x-direction ends 29a and 29b, the bottom 23 of the receding portion 21 can also be called an end region 24. The following mainly describes the parts that are different from the semiconductor laser 100 and the semiconductor laser device 200 of the second embodiment.

[0100] Fig.25 The first semiconductor laser 100 of the fourth embodiment shown in FIG. Fig.29 The third semiconductor laser 100 of the fourth embodiment shown is an example in which a groove 19 is provided, and the inner surface of the groove 19 and the surface of the p-type contact layer 10 in the end region 24 are covered with a semi-insulating layer 11. The bottom 22 of the groove 19 may be arranged at any position in the z direction from the p-type second cladding layer 9 to the inside of the n-type semiconductor substrate 1. Fig.29 The third semiconductor laser 100 of the fourth embodiment shown is an example in which the bottom 22 of the trench 19 is arranged at a position in the z direction of the n-type semiconductor substrate 1. Fig.29 , an example is shown in which the bottom 22 of the trench 19 is arranged on the back surface side of the n-type semiconductor substrate 1 rather than the surface of the n-type semiconductor substrate 1 formed on the ridge 5 . Fig.25 The first semiconductor laser 100 of the fourth embodiment shown in FIG. Fig.29The semi-insulating layer 11 of the third semiconductor laser 100 of the fourth embodiment shown is directly formed on the inner surface of the groove 19 and on the positive side of the p-type contact layer 10 in the z direction from the first side surface 46 of the groove 19 to the end in the x direction on the side opposite to the protrusion 18 of the semiconductor laser 100 (x-direction ends 29a, 29b).

[0101] The second semiconductor laser 100 of the fourth embodiment includes a setback portion 21 extending in the y direction between the side surface of the ridge portion 50 on the positive side in the x direction and the end portion (x-direction end portion 29b) of the semiconductor laser 100 on the positive side in the x direction, and between the side surface of the ridge portion 50 on the negative side in the x direction and the end portion (x-direction end portion 29a) of the semiconductor laser 100 on the negative side in the x direction. Each setback portion 21 has the p-type contact layer 10 removed, and the bottom 23 of the setback portion 21 is arranged at an arbitrary position in the z direction from the p-type second cladding layer 9 to the inside of the n-type semiconductor substrate 1. The semi-insulating layer 11 is directly formed on the side surface (setback portion side surface 48) and the bottom 23 of the setback portion 21 on the positive side in the x direction, and the side surface (setback portion side surface 48) and the bottom 23 of the setback portion 21 on the negative side in the x direction.

[0102] Fig.26 An example of a semiconductor laser device 200 is shown in which the connecting component 14 is filled in the groove 19, the position of the negative side of the connecting component 14 in the z direction covers a portion of the second buried layer 7 at the x-direction ends 29a and 29b, and the first semiconductor laser 100 of embodiment 4 is mounted on the heat sink 17 in the following bonding manner. Fig.28 An example of a semiconductor laser device 200 is shown in which the connection member 14 is filled in the recessed portion 21, the position of the negative side of the connection member 14 in the z direction covers a part of the second buried layer 7 at the x-direction ends 29a and 29b, and the second semiconductor laser 100 of the fourth embodiment is mounted on the heat sink 17 in the following bonding manner. The convex portion 18 formed between the two recessed portions 21 is the same as the convex portion 18 formed between the two grooves 19. The width in the x direction of any convex portion 18, that is, the convex portion width W2, is larger than the width in the x direction of the ridge portion 50, that is, the ridge portion width W1.

[0103] exist Fig.25 , Fig.29 , an example is shown in which the inner surface of the groove 19 and the semi-insulating layer 11 on the positive side of the end region 24 in the z direction are exposed. However, this is not limiting, and the surface of the semi-insulating layer 11 may also be covered by the anode electrode 12 or a metal that is not connected to the anode electrode 12. Fig. 27, an example is shown in which the semi-insulating layer 11 is exposed on the side surface 48 of the receding portion 21 and the positive side in the z direction of the bottom 23. However, this is not limiting, and the surface of the semi-insulating layer 11 may also be covered with the anode electrode 12 or a metal not connected to the anode electrode 12.

[0104] Next, use the above Figures 4 to 7 as well as Figure 31 to Figure 34 As an example shown, a method for manufacturing the first or third semiconductor laser 100 according to the fourth embodiment will be described. Figures 4 to 7 The ridge forming process and embedding process shown are the same as those in Embodiment 1. Figure 7 Indicates the state before the stacking process begins, and also indicates the end state of the embedding process. Figure 7 After the embedding process shown in the figure, Fig.31 In the lamination step, a p-type second cladding layer 9 and a p-type contact layer 10 are sequentially formed on the positive side of the ridge 5 in the z direction and on the positive side of the n-type third buried layer 8 in the z direction. Fig.32 The trench forming step shown in FIG. In the trench forming step, in the semiconductor layer formed to the p-type contact layer 10, two trenches 19 are formed on both sides of the ridge 50 in the x direction using the resist mask 32 so that the bottom 22 is located at an arbitrary position in the z direction from the p-type second cladding layer 9 to the inside of the n-type semiconductor substrate 1. More specifically, in the trench forming step, the p-type contact layer 10 is etched at two outer edges away from the ridge 50 on the positive side and the negative side of the x direction to form the trench 19 in which the position of the bottom 22 in the z direction is etched to an arbitrary position in the z direction from the p-type second cladding layer 9 to the inside of the n-type semiconductor substrate 1.

[0105] Next, a semi-insulating layer forming step is performed to form the semi-insulating layer 11. In the semi-insulating layer forming step, Fig.33 As shown in FIG. 1 , a second mask 33 of SiO2, SiN or the like is formed on the positive side of the convex portion 18 in the z direction. Fig.34 As shown, the semi-insulating layer 11 is formed in the region other than the positive side in the z direction of the convex portion 18. The semi-insulating layer 11 is formed by selective growth. More specifically, the semi-insulating layer 11 is directly formed on the positive side in the z direction of the p-type contact layer 10 which is away from the side of the convex portion 18 formed between the two grooves 19 and is outside the groove 19 in the x direction, and on the inner surfaces of the two grooves 19. Then, the second mask 33 is removed using buffered hydrofluoric acid or hydrofluoric acid.

[0106] Then, the following steps are performed: a surface side electrode forming step, in which an anode electrode 12 is formed by covering the p-type contact layer 10 of the convex portion 18 on which the semi-insulating layer 11 is not formed by the insulating layer forming step; and a back side electrode forming step, in which a cathode electrode 13 is formed on the back side of the n-type semiconductor substrate 1, i.e., the negative side in the z direction. The anode electrode 12 is patterned using a resist mask. The first or third semiconductor laser 100 of the fourth embodiment is manufactured by the above steps.

[0107] Next, a method for manufacturing the second semiconductor laser 100 according to the fourth embodiment will be described using an example. Fig.31 , which is the same as the manufacturing method of the first or third semiconductor laser 100 of embodiment 4. Then, the receding portion forming process is performed in the same manner as the groove forming process. In the receding portion forming process, in the semiconductor layer formed to the p-type contact layer 10, two receding portions 21 are formed on both sides of the ridge 50 in the x direction using the resist mask 32 formed on the positive side of the convex portion 18 in the z direction, so that the bottom 23 is located at an arbitrary position in the z direction from the p-type second cladding layer 9 to the inside of the n-type semiconductor substrate 1. More specifically, in the receding portion forming process, the p-type contact layer 10 is etched at the two outer edges away from the ridge 50 on the positive and negative sides of the x direction, forming a receding portion 21 in which the position of the bottom 23 in the z direction is etched to an arbitrary position in the z direction from the p-type second cladding layer 9 to the inside of the n-type semiconductor substrate 1.

[0108] Next, a semi-insulating layer forming step is performed to form the semi-insulating layer 11. In the semi-insulating layer forming step, Fig.33 Similarly, a second mask 33 is formed on the positive side of the convex portion 18 in the z direction. Fig.34 Similarly, the semi-insulating layer 11 is formed in the region other than the positive side in the z direction of the convex portion 18. More specifically, the semi-insulating layer 11 is directly formed on the side surface (recessed portion side surface 48) and the bottom 23 of the receding portion 21 on the positive side in the x direction, and on the side surface (recessed portion side surface 48) and the bottom 23 of the receding portion 21 on the negative side in the x direction. Then, the second mask 33 is removed using buffered hydrofluoric acid or hydrofluoric acid.

[0109] Next, the following steps are performed: a surface side electrode forming step, in which an anode electrode 12 is formed by covering the p-type contact layer 10 of the convex portion 18 on which the semi-insulating layer 11 is not formed by the insulating layer forming step; and a back side electrode forming step, in which a cathode electrode 13 is formed on the back side of the n-type semiconductor substrate 1, i.e., the negative side in the z direction. The anode electrode 12 is patterned using a resist mask. The second semiconductor laser 100 of the fourth embodiment is manufactured by the above steps.

[0110] The semiconductor laser 100 of the fourth embodiment can reduce the area of ​​the second buried layer 7 side of the n-type third buried layer 8 by the groove 19 or the receding portion 21, and can also reduce the area of ​​the second buried layer 7 side of the n-type third buried layer 8 near the active layer 3. Therefore, the semiconductor laser 100 and the semiconductor laser device 200 of the fourth embodiment have the same effect as the semiconductor laser 100 and the semiconductor laser device 200 of the second embodiment. The semiconductor laser 100 of the fourth embodiment can also dissipate heat from the inner surface of the groove 19 (the first side surface 46 of the groove, the second side surface 47 of the groove, and the bottom 22) or the receding portion side surface and the bottom 23 of the receding portion 21 by using the semi-insulating layer 11 with high thermal conductivity instead of the insulating film 15, so that the high temperature characteristics can be further improved than the semiconductor laser 100 of the second embodiment.

[0111] As described above, the first or third semiconductor laser 100 of the fourth embodiment is a semiconductor laser mounted on the surface of the side protruding from the ridge 5, which includes a ridge 5 formed on an n-type semiconductor substrate 1 and a buried layer 25 buried to cover both sides opposite to each other in a direction perpendicular to the extension direction of the ridge 5. The z direction, y direction, and x direction are as described above. The ridge 5 has an n-type cladding layer 2, an active layer 3, and a p-type first cladding layer 4 formed in sequence from the n-type semiconductor substrate 1 side. The buried layer 25 has a p-type first buried layer 6, a second buried layer 7, and an n-type third buried layer 8 that are in contact with the side surface of the ridge 5 on the positive side in the x direction and the side surface on the negative side in the x direction. The semiconductor laser 100 includes a p-type second cladding layer 9, a p-type contact layer 10, a surface-side electrode (anode electrode 12) connected to the p-type contact layer 10, and a semi-insulating layer 11 formed on the outer edge of the ridge 50 including the ridge 5 and the p-type first buried layer 6 in contact with both side surfaces of the ridge 5, which are formed in order from the n-type semiconductor substrate 1 side on the positive side in the z direction of the ridge 5 and the positive side in the z direction of the n-type third buried layer 8, and formed in the x direction away from the outer edge of the ridge 50 including the ridge 5 and the p-type first buried layer 6 in contact with both side surfaces of the ridge 5, and the semi-insulating layer 11 is formed on the positive side in the z direction on the side of the x direction end (x-direction end 29a, 29b) of the semiconductor laser 100. Grooves 19 extending in the y direction are provided between the side surface on the positive side in the x direction of the ridge 50 and the end on the positive side in the x direction (x-direction end 29b) of the semiconductor laser 100, and between the side surface on the negative side in the x direction of the ridge 50 and the end on the negative side in the x direction (x-direction end 29a) of the semiconductor laser 100. Each groove 19 penetrates the p-type contact layer 10, and the bottom 22 of the groove 19 is arranged at an arbitrary position in the z direction from the p-type second cladding layer 9 to the inside of the n-type semiconductor substrate 1. The surface side electrode (anode electrode 12) is connected to the p-type contact layer 10 in the convex portion 18 formed between the two grooves 19. The semi-insulating layer 11 is directly formed on the inner surface of the groove 19 and the positive side of the p-type contact layer 10 in the z direction from the groove first side surface 46 of the groove 19 to the end (x-direction end 29a, 29b) of the semiconductor laser 100 on the side opposite to the convex portion 18. With this configuration, the first or third semiconductor laser 100 of the fourth embodiment has the semi-insulating layer 11 on the outer edge on the side away from the ridge 50 having the active layer 3 and opposite to the n-type semiconductor substrate 1 in the x direction. Therefore, when mounted from the surface side electrode (anode electrode 12) side, it is possible to suppress leakage current that does not contribute to laser oscillation and achieve excellent heat dissipation.

[0112] In addition, the third semiconductor laser 100 of the fourth embodiment is a semiconductor laser mounted on the surface of the side protruding from the ridge 5, including a ridge 5 formed on an n-type semiconductor substrate 1 and a buried layer 25 buried so as to cover both sides opposed to each other in a direction perpendicular to the extension direction of the ridge 5. The ridge 5 has an n-type cladding layer 2, an active layer 3, and a p-type first cladding layer 4 formed in sequence from the n-type semiconductor substrate 1 side. The buried layer 25 has a p-type first buried layer 6, a second buried layer 7, and an n-type third buried layer 8 that are in contact with the side surface of the ridge 5 on the positive side in the x direction and the side surface on the negative side in the x direction. The semiconductor laser 100 includes a p-type second cladding layer 9, a p-type contact layer 10, a surface-side electrode (anode electrode 12) connected to the p-type contact layer 10, and a semi-insulating layer 11 formed on the outer edge of the ridge 50 including the ridge 5 and the p-type first buried layer 6 in contact with both side surfaces of the ridge 5, which are formed in order from the n-type semiconductor substrate 1 side on the positive side in the z direction of the ridge 5 and the positive side in the z direction of the n-type third buried layer 8, and formed in the x direction away from the outer edge of the ridge 50 including the ridge 5 and the p-type first buried layer 6 in contact with both side surfaces of the ridge 5, and the semi-insulating layer 11 is formed on the positive side in the z direction on the side of the x direction end (x-direction end 29a, 29b) of the semiconductor laser 100. A retreat portion 21 extending in the y direction is provided between the side surface on the positive side in the x direction of the ridge 50 and the end on the positive side in the x direction (x-direction end 29b) of the semiconductor laser 100, and between the side surface on the negative side in the x direction of the ridge 50 and the end on the negative side in the x direction (x-direction end 29a) of the semiconductor laser 100. The p-type contact layer 10 is removed from each of the recessed portions 21, and the bottom 23 of the recessed portion 21 is arranged at an arbitrary position in the z direction from the p-type second cladding layer 9 to the inside of the n-type semiconductor substrate 1. The surface-side electrode (anode electrode 12) is connected to the p-type contact layer 10 in the convex portion 18 formed between the two recessed portions 21. The semi-insulating layer 11 is directly formed on the side surface (recessed portion side surface 48) and the bottom 23 of the recessed portion 21 on the positive side in the x direction, and the side surface (recessed portion side surface 48) and the bottom 23 of the recessed portion 21 on the negative side in the x direction. The third semiconductor laser 100 of the fourth embodiment has the semi-insulating layer 11 on the outer edge on the side away from the ridge portion 50 having the active layer 3 in the x direction and opposite to the n-type semiconductor substrate 1. Therefore, when mounted from the surface-side electrode (anode electrode 12) side, it is possible to suppress leakage current that does not contribute to laser oscillation and achieve excellent heat dissipation.

[0113] The method for manufacturing a semiconductor laser of the fourth embodiment is a method for manufacturing a semiconductor laser 100 having a ridge 5 formed on an n-type semiconductor substrate 1 and a buried layer 25 buried to cover both sides opposite to each other in a direction perpendicular to the extension direction of the ridge 5. The method for manufacturing a semiconductor laser of the fourth embodiment includes a ridge forming step, a burying step, a laminating step, a groove forming step, a semi-insulating layer forming step, and a surface side electrode forming step described later. In the ridge forming step, an n-type cladding layer 2, an active layer 3, and a p-type first cladding layer 4 are sequentially formed on the n-type semiconductor substrate 1, and the ridge 5 having the n-type cladding layer 2, the active layer 3, and the p-type first cladding layer 4 is formed by etching to a position lower than the n-type semiconductor substrate 1 side of the active layer 3, that is, the negative side in the z direction, and the positive side side in the x direction and the negative side side in the x direction are exposed. In the embedding step, a p-type first embedding layer 6 is formed on the side surface on the positive side in the x direction and the side surface on the negative side in the x direction of the ridge 5, and the ridge 5 is embedded to a position higher than the positive side position in the z direction of the active layer 3, that is, the active layer surface position 44, by the second embedding layer 7 and the n-type third embedding layer 8 formed in sequence. In the stacking step, a p-type second cladding layer 9 and a p-type contact layer 10 are formed in sequence on the positive side in the z direction of the ridge 5 and the positive side in the z direction of the n-type third embedding layer 8. In the groove forming step, the p-type contact layer 10 is etched away from the two outer edges of the ridge portion 50 on the positive side and the negative side in the x direction, and a groove 19 is formed in which the position of the bottom 22 in the z direction is etched to an arbitrary position in the z direction from the p-type second cladding layer 9 to the inside of the n-type semiconductor substrate 1, wherein the ridge portion 50 includes the ridge 5 and the p-type first embedding layer 6 in contact with the two side surfaces of the ridge 5. In the semi-insulating layer forming step, the semi-insulating layer 11 is directly formed on the positive side in the z direction of the p-type contact layer 10 on the outside of the grooves 19 and on the inner surface of the two grooves 19, which is away from the convex portion 18 formed between the two grooves 19 in the x direction. In the surface side electrode forming step, the surface side electrode (anode electrode 12) is formed in a manner to cover the p-type contact layer 10 of the convex portion 18 on which the semi-insulating layer 11 is not formed by the semi-insulating layer forming step. The method for manufacturing a semiconductor laser of the fourth embodiment can manufacture a semiconductor laser 100 having a semi-insulating layer 11 on the outer edge of the side opposite to the n-type semiconductor substrate 1 and away from the ridge portion 50 having the active layer 3 in the x direction, so that when mounted from the surface side electrode (anode electrode 12) side, leakage current that does not contribute to laser oscillation can be suppressed and excellent heat dissipation can be achieved.

[0114] In addition, the manufacturing method of another semiconductor laser of the fourth embodiment is a manufacturing method of a semiconductor laser 100 having a ridge 5 formed on an n-type semiconductor substrate 1 and a buried layer 25 buried to cover both sides opposite to each other in a direction perpendicular to the extension direction of the ridge 5. The manufacturing method of another semiconductor laser of the fourth embodiment includes a ridge forming step, a burying step, a laminating step, a receding portion forming step, a semi-insulating layer forming step, and a surface side electrode forming step described later. In the ridge forming step, an n-type cladding layer 2, an active layer 3, and a p-type first cladding layer 4 are sequentially formed on the n-type semiconductor substrate 1, and the ridge 5 having the n-type cladding layer 2, the active layer 3, and the p-type first cladding layer 4 is formed by etching to a position lower than the n-type semiconductor substrate 1 side of the active layer 3, that is, the negative side in the z direction, and the positive side side in the x direction and the negative side side in the x direction are exposed. In the embedding step, a p-type first embedding layer 6 is formed on the side surface on the positive side in the x direction and the side surface on the negative side in the x direction of the ridge 5, and the ridge 5 is embedded to a position higher than the positive side position in the z direction of the active layer 3, that is, the active layer surface position 44, by the second embedding layer 7 and the n-type third embedding layer 8 formed in sequence. In the stacking step, a p-type second cladding layer 9 and a p-type contact layer 10 are formed in sequence on the positive side in the z direction of the ridge 5 and the positive side in the z direction of the n-type third embedding layer 8. In the receding portion forming step, the p-type contact layer 10 is etched away from the two outer edges of the ridge 50 on the positive side and the negative side in the x direction, and the receding portion 21 is formed, wherein the position of the bottom 23 in the z direction is etched to an arbitrary position in the z direction from the p-type second cladding layer 9 to the inside of the n-type semiconductor substrate 1, wherein the ridge 50 includes the ridge 5 and the p-type first embedding layer 6 in contact with the two side surfaces of the ridge 5. In the semi-insulating layer forming step, the semi-insulating layer 11 is directly formed on the side surface (recessed portion side surface 48) and the bottom 23 of the retreated portion 21 on the positive side in the x direction, and on the side surface (recessed portion side surface 48) and the bottom 23 of the retreated portion 21 on the negative side in the x direction. In the surface side electrode forming step, the surface side electrode (anode electrode 12) is formed so as to cover the p-type contact layer 10 of the convex portion 18 formed between the two retreated portions 21, which is not formed with the semi-insulating layer 11 by the semi-insulating layer forming step. The method for manufacturing another semiconductor laser of the fourth embodiment can manufacture a semiconductor laser 100 having a semi-insulating layer 11 on the outer edge of the side away from the ridge portion 50 having the active layer 3 and opposite to the n-type semiconductor substrate 1 in the x direction, so that when mounted from the surface side electrode (anode electrode 12) side, it is possible to suppress leakage current that does not contribute to laser oscillation and achieve excellent heat dissipation.

[0115] Implementation method 5.

[0116] Fig.35 is a diagram showing a cross-sectional structure of a first semiconductor laser according to Embodiment 5, Fig.36 It is a diagram showing a cross-sectional structure of a first semiconductor laser device according to a fifth embodiment. Fig.37 is a diagram showing a cross-sectional structure of a second semiconductor laser according to Embodiment 5, Fig.38 It is a diagram showing a cross-sectional structure of a second semiconductor laser device according to the fifth embodiment. Fig.39 It is a diagram showing a cross-sectional structure of a third semiconductor laser according to the fifth embodiment. Fig.40 Yes means Fig.35 FIG. 5 is a diagram of a method for manufacturing a semiconductor laser. The semiconductor laser 100 of the fifth embodiment is different from the semiconductor laser 100 of the fourth embodiment in that the two side surfaces of the convex portion 18 in the x direction and the semi-insulating layer 11 from the two side surfaces to the ends 29a and 29b in the x direction are formed via the n-type diffusion barrier layer 16. The following mainly describes the parts that are different from the semiconductor laser 100 and the semiconductor laser device 200 of the fourth embodiment.

[0117] Fig.35 The first semiconductor laser 100 of the fifth embodiment shown in FIG. Fig.39 The third semiconductor laser 100 of the fifth embodiment shown is an example in which a groove 19 is provided, and the inner surface of the groove 19 and the surface of the p-type contact layer 10 in the end region 24 are covered by the semi-insulating layer 11 via the n-type diffusion barrier layer 16. The bottom 22 of the groove 19 may be arranged at any position in the z direction from the p-type second cladding layer 9 to the inside of the n-type semiconductor substrate 1. Fig.39 The third semiconductor laser 100 of the fifth embodiment shown is an example in which the bottom 22 of the trench 19 is arranged at a position in the z direction of the n-type semiconductor substrate 1. Fig.39 , an example is shown in which the bottom 22 of the trench 19 is arranged on the back surface side of the n-type semiconductor substrate 1 rather than the surface of the n-type semiconductor substrate 1 formed on the ridge 5 . Fig.35 The first semiconductor laser 100 of the fifth embodiment shown in FIG. Fig.39 In the third semiconductor laser 100 of the fifth embodiment shown, the semi-insulating layer 11 is formed via the n-type diffusion barrier layer 16 on the inner surface of the groove 19 and on the positive side of the p-type contact layer 10 in the z direction from the first side surface 46 of the groove 19 to the end in the x direction on the side opposite to the protrusion 18 of the semiconductor laser 100 (x-direction ends 29a, 29b).

[0118] Fig.37The second semiconductor laser 100 of the fifth embodiment shown in the figure includes two receding portions 21, each of which has a p-type contact layer 10 removed, and a bottom 23 of the receding portion 21 is arranged at an arbitrary position in the z direction from the p-type second cladding layer 9 to the inside of the n-type semiconductor substrate 1. The semi-insulating layer 11 is formed on the side surface (recessed portion side surface 48) and bottom 23 of the receding portion 21 on the positive side in the x direction, and on the side surface (recessed portion side surface 48) and bottom 23 of the receding portion 21 on the negative side in the x direction via the n-type diffusion barrier layer 16.

[0119] Next, use the above Figures 4 to 7 , Figure 31 to Figure 33 as well as Fig.40 As an example, a method for manufacturing the first or third semiconductor laser 100 according to Embodiment 5 will be described. The method for manufacturing the first or third semiconductor laser 100 according to Embodiment 5 is different from the method for manufacturing the first or third semiconductor laser 100 according to Embodiment 4 in the step of forming a semi-insulating layer. Figures 4 to 7 The ridge forming process and embedding process shown are the same as those in Embodiment 1. Figure 7 It shows the state before the stacking process starts, and also shows the end state of the embedding process. Figure 31 to Figure 33 The stacking step, the trench forming step, and the second mask forming step of the semi-insulating layer forming step are the same as those in the fourth embodiment.

[0120] The semi-insulating layer forming process is described below. Fig.40 As shown, the n-type diffusion barrier layer 16 and the semi-insulating layer 11 are sequentially formed in the region other than the positive side in the z direction of the convex portion 18 using the second mask 33. The n-type diffusion barrier layer 16 and the semi-insulating layer 11 are formed by selective growth. More specifically, the semi-insulating layer 11 is formed via the n-type diffusion barrier layer 16 on the positive side in the z direction of the p-type contact layer 10 in the outer side of the groove 19 away from the convex portion 18 formed between the two grooves 19 in the x direction and on the inner surface of the two grooves 19. Then, the second mask 33 is removed using buffered hydrofluoric acid or hydrofluoric acid.

[0121] Next, the following steps are performed: a surface side electrode forming step, in which an anode electrode 12 is formed by covering the p-type contact layer 10 of the convex portion 18 on which the semi-insulating layer 11 is not formed by the insulating layer forming step; and a back side electrode forming step, in which a cathode electrode 13 is formed on the back side of the n-type semiconductor substrate 1, i.e., the negative side in the z direction. The anode electrode 12 is patterned using a resist mask. The first or third semiconductor laser 100 of the fifth embodiment is manufactured by the above steps.

[0122] Next, a method for manufacturing the second semiconductor laser 100 according to the fifth embodiment will be described using an example. Fig.31 , which is the same as the manufacturing method of the second semiconductor laser 100 in Embodiment 4. Then, the receding portion forming step of forming the receding portion 21 is performed in the same manner as the second semiconductor laser 100 in Embodiment 4. Next, the semi-insulating layer forming step of forming the semi-insulating layer 11 is performed. In the semi-insulating layer forming step, Fig.33 Similarly, a second mask 33 is formed on the positive side of the convex portion 18 in the z direction. Fig.40 Similarly, an n-type diffusion barrier layer 16 and a semi-insulating layer 11 are sequentially formed in the region other than the positive side of the convex portion 18 in the z direction. The n-type diffusion barrier layer 16 and the semi-insulating layer 11 are formed by selective growth. More specifically, the semi-insulating layer 11 is formed via the n-type diffusion barrier layer 16 on the side surface (recessed portion side surface 48) and the bottom 23 of the receding portion 21 on the positive side in the x direction, and on the side surface (recessed portion side surface 48) and the bottom 23 of the receding portion 21 on the negative side in the x direction. Then, the second mask 33 is removed using buffered hydrofluoric acid or hydrofluoric acid. Next, the same insulating layer forming step as the first or third semiconductor laser 100 of embodiment 5 is performed to form the anode electrode 12 and the cathode electrode 13.

[0123] The semiconductor laser 100 of the fifth embodiment can reduce the area of ​​the n-type third buried layer 8 on the second buried layer 7 side by the groove 19 or the retreated portion 21, and can also reduce the area of ​​the n-type third buried layer 8 on the second buried layer 7 side near the active layer 3. Therefore, the semiconductor laser 100 and the semiconductor laser device 200 of the fifth embodiment have the same effects as the semiconductor laser 100 and the semiconductor laser device 200 of the fourth embodiment.

[0124] The semiconductor laser 100 of the fourth embodiment covers the convex portion 18 except the positive side in the z direction with the semi-insulating layer 11. However, if zinc or the like doped in the p-type second cladding layer 9 and the p-type contact layer 10 diffuses into the semi-insulating layer 11 doped with iron or the like, the semi-insulating property of the semi-insulating layer 11 may be weakened, and the leakage current blocking effect of the semi-insulating layer 11 may be weakened. Therefore, the semiconductor laser 100 of the fifth embodiment forms the n-type diffusion barrier layer 16 and forms the semi-insulating layer 11 on the surface of the n-type diffusion barrier layer 16, so that zinc or the like doped in the p-type second cladding layer 9 and the p-type contact layer 10 can be prevented from diffusing into the buried layer 25. As a result, the semiconductor laser 100 of the fifth embodiment can prevent the diffusion of zinc or the like, which is a major factor in reducing the semi-insulating property of the semi-insulating layer 11, and reduce the parasitic capacitance of the buried layer 25, thereby improving the effective current injection into the active layer 3 and the heat dissipation of the heat generated in the active layer 3, as compared with the semiconductor laser 100 of the fourth embodiment.

[0125] As described above, the first or third semiconductor laser 100 of the fifth embodiment is a semiconductor laser mounted on the surface of the side protruding from the ridge 5, which includes a ridge 5 formed on an n-type semiconductor substrate 1 and a buried layer 25 buried to cover both sides opposite to each other in a direction perpendicular to the extension direction of the ridge 5. The z direction, y direction, and x direction are as described above. The ridge 5 has an n-type cladding layer 2, an active layer 3, and a p-type first cladding layer 4 formed in sequence from the n-type semiconductor substrate 1 side. The buried layer 25 has a p-type first buried layer 6, a second buried layer 7, and an n-type third buried layer 8 that are in contact with the side surface of the ridge 5 on the positive side in the x direction and the side surface on the negative side in the x direction. The semiconductor laser 100 includes a p-type second cladding layer 9, a p-type contact layer 10, a surface-side electrode (anode electrode 12) connected to the p-type contact layer 10, and a semi-insulating layer 11 formed in the x direction away from the outer edge of the ridge 50 including the ridge 5 and the p-type first buried layer 6 in contact with both side surfaces of the ridge 5, which are formed in this order from the n-type semiconductor substrate 1 side on the positive side in the z direction of the ridge 5 and the positive side in the z direction of the n-type third buried layer 8. The semi-insulating layer 11 is formed on the positive side in the z direction on the side of the x-direction end (x-direction end 29a, 29b) of the semiconductor laser 100. Grooves 19 extending in the y direction are provided between the side surface on the positive side in the x direction of the ridge 50 and the end on the positive side in the x direction (x-direction end 29b) of the semiconductor laser 100, and between the side surface on the negative side in the x direction of the ridge 50 and the end on the negative side in the x direction (x-direction end 29a) of the semiconductor laser 100. Each groove 19 penetrates the p-type contact layer 10, and the bottom 22 of the groove 19 is arranged at an arbitrary position in the z direction from the p-type second cladding layer 9 to the inside of the n-type semiconductor substrate 1. The surface side electrode (anode electrode 12) is connected to the p-type contact layer 10 in the convex portion 18 formed between the two grooves 19. The semi-insulating layer 11 is formed on the inner surface of the groove 19 and on the positive side of the p-type contact layer 10 in the z direction from the groove first side surface 46 of the groove 19 to the end (x-direction end 29a, 29b) of the semiconductor laser 100 on the side opposite to the convex portion 18 via the n-type diffusion barrier layer. The first or third semiconductor laser 100 of embodiment 5 has this structure, and has a semi-insulating layer 11 on the outer edge on the side opposite to the n-type semiconductor substrate 1 and away from the ridge 50 having the active layer 3 in the x direction. Therefore, when installed from the surface side electrode (anode electrode 12), it is possible to suppress leakage current that does not contribute to laser oscillation and achieve excellent heat dissipation.

[0126] In addition, the third semiconductor laser 100 of the fifth embodiment is a semiconductor laser mounted on the surface of the side protruding from the ridge 5, including a ridge 5 formed on an n-type semiconductor substrate 1 and a buried layer 25 buried so as to cover both sides opposed to each other in a direction perpendicular to the extension direction of the ridge 5. The ridge 5 has an n-type cladding layer 2, an active layer 3, and a p-type first cladding layer 4 formed in this order from the n-type semiconductor substrate 1 side. The buried layer 25 has a p-type first buried layer 6, a second buried layer 7, and an n-type third buried layer 8 that are in contact with the side surface of the ridge 5 on the positive side in the x direction and the side surface on the negative side in the x direction. The semiconductor laser 100 includes a p-type second cladding layer 9, a p-type contact layer 10, a surface-side electrode (anode electrode 12) connected to the p-type contact layer 10, and a semi-insulating layer 11 formed in the x direction away from the outer edge of the ridge 50 including the ridge 5 and the p-type first buried layer 6 in contact with both side surfaces of the ridge 5, which are formed in this order from the n-type semiconductor substrate 1 side on the positive side in the z direction of the ridge 5 and the positive side in the z direction of the n-type third buried layer 8. The semi-insulating layer 11 is formed on the positive side in the z direction on the side of the x-direction end (x-direction end 29a, 29b) of the semiconductor laser 100. The retreat portion 21 extending in the y direction is provided between the side surface on the positive side in the x direction of the ridge 50 and the end on the positive side in the x direction (x-direction end 29b) of the semiconductor laser 100, and between the side surface on the negative side in the x direction of the ridge 50 and the end on the negative side in the x direction (x-direction end 29a) of the semiconductor laser 100. Each of the recessed portions 21 has the p-type contact layer 10 removed, and the bottom 23 of the recessed portion 21 is arranged at an arbitrary position in the z direction from the p-type second cladding layer 9 to the inside of the n-type semiconductor substrate 1. The surface-side electrode (anode electrode 12) is connected to the p-type contact layer 10 formed in the convex portion 18 between the two recessed portions 21. The semi-insulating layer 11 is formed on the side surface (recessed portion side surface 48) and the bottom 23 of the recessed portion 21 on the positive side in the x direction, and on the side surface (recessed portion side surface 48) and the bottom 23 of the recessed portion 21 on the negative side in the x direction via the n-type diffusion barrier layer 16. The third semiconductor laser 100 of the fifth embodiment has the semi-insulating layer 11 on the outer edge of the side away from the ridge portion 50 having the active layer 3 and opposite to the n-type semiconductor substrate 1 in the x direction, so when mounted from the surface-side electrode (anode electrode 12) side, it is possible to suppress leakage current that does not contribute to laser oscillation and achieve excellent heat dissipation.

[0127] The method for manufacturing a semiconductor laser of the fifth embodiment is a method for manufacturing a semiconductor laser 100 having a ridge 5 formed on an n-type semiconductor substrate 1 and a buried layer 25 buried to cover both sides opposite to each other in a direction perpendicular to the extension direction of the ridge 5. The method for manufacturing a semiconductor laser of the fifth embodiment includes a ridge forming step, a burying step, a laminating step, a groove forming step, a semi-insulating layer forming step, and a surface side electrode forming step described later. In the ridge forming step, an n-type cladding layer 2, an active layer 3, and a p-type first cladding layer 4 are sequentially formed on the n-type semiconductor substrate 1, and the ridge 5 having the n-type cladding layer 2, the active layer 3, and the p-type first cladding layer 4 is formed by etching to a position lower than the n-type semiconductor substrate 1 side of the active layer 3, that is, the negative side in the z direction, and the positive side side in the x direction and the negative side side in the x direction are exposed. In the embedding step, a p-type first embedding layer 6 is formed on the side surface on the positive side in the x direction and the side surface on the negative side in the x direction of the ridge 5, and the ridge 5 is embedded to a position higher than the positive side position in the z direction of the active layer, that is, the active layer surface position 44, by the second embedding layer 7 and the n-type third embedding layer 8 formed in sequence. In the stacking step, a p-type second cladding layer 9 and a p-type contact layer 10 are formed in sequence on the positive side in the z direction of the ridge 5 and the positive side in the z direction of the n-type third embedding layer 8. In the groove forming step, the p-type contact layer 10 is etched away from the two outer edges of the ridge portion 50 on the positive side and the negative side in the x direction, and a groove 19 is formed in which the position of the bottom 22 in the z direction is etched to an arbitrary position in the z direction from the p-type second cladding layer 9 to the inside of the n-type semiconductor substrate 1, wherein the ridge portion 50 includes the ridge 5 and the p-type first embedding layer 6 in contact with the two side surfaces of the ridge 5. In the semi-insulating layer forming step, the semi-insulating layer 11 is formed via the n-type diffusion barrier layer 16 on the positive side in the z direction of the p-type contact layer 10 on the outside of the grooves 19 and on the inner surface of the two grooves 19, which is away from the convex portion 18 formed between the two grooves 19 in the x direction. In the surface side electrode forming step, the surface side electrode (anode electrode 12) is formed so as to cover the p-type contact layer 10 of the convex portion 18 on which the semi-insulating layer 11 is not formed by the semi-insulating layer forming step. The method for manufacturing a semiconductor laser of the fifth embodiment can manufacture a semiconductor laser 100 having a semi-insulating layer 11 on the outer edge of the side opposite to the n-type semiconductor substrate 1 and away from the ridge portion 50 having the active layer 3 in the x direction, so that when mounted from the surface side electrode (anode electrode 12) side, it is possible to suppress leakage current that does not contribute to laser oscillation and achieve excellent heat dissipation.

[0128] In addition, the manufacturing method of another semiconductor laser of the fifth embodiment is a manufacturing method of a semiconductor laser 100 having a ridge 5 formed on an n-type semiconductor substrate 1 and a buried layer 25 buried to cover both sides opposite to each other in a direction perpendicular to the extension direction of the ridge 5. The manufacturing method of another semiconductor laser of the fifth embodiment includes a ridge forming step, a burying step, a laminating step, a receding portion forming step, a semi-insulating layer forming step, and a surface side electrode forming step described later. In the ridge forming step, an n-type cladding layer 2, an active layer 3, and a p-type first cladding layer 4 are sequentially formed on the n-type semiconductor substrate 1, and the ridge 5 having the n-type cladding layer 2, the active layer 3, and the p-type first cladding layer 4 is formed by etching to a position lower than the n-type semiconductor substrate 1 side of the active layer 3, that is, the negative side in the z direction, and the positive side side in the x direction and the negative side side in the x direction are exposed. In the embedding step, a p-type first embedding layer 6 is formed on the side surface on the positive side in the x direction and the side surface on the negative side in the x direction of the ridge 5, and the ridge 5 is embedded to a position higher than the positive side position in the z direction of the active layer, that is, the active layer surface position 44, by the second embedding layer 7 and the n-type third embedding layer 8 formed in sequence. In the stacking step, a p-type second cladding layer 9 and a p-type contact layer 10 are formed in sequence on the positive side in the z direction of the ridge 5 and the positive side in the z direction of the n-type third embedding layer 8. In the receding portion forming step, the p-type contact layer 10 is etched away from the two outer edges of the ridge portion 50 including the ridge 5 and the p-type first embedding layer 6 in contact with the two side surfaces of the ridge 5 on the positive and negative sides in the x direction, and the receding portion 21 is formed in which the position in the z direction of the bottom 23 is etched to an arbitrary position in the z direction from the p-type second cladding layer 9 to the inside of the n-type semiconductor substrate 1. In the semi-insulating layer forming step, a semi-insulating layer is formed via the n-type diffusion barrier layer 16 on the side surface (recessed portion side surface 48) and the bottom 23 of the retreated portion 21 on the positive side in the x direction, and on the side surface (recessed portion side surface 48) and the bottom 23 of the retreated portion 21 on the negative side in the x direction. In the surface side electrode forming step, the surface side electrode (anode electrode 12) is formed so as to cover the p-type contact layer 10 of the convex portion 18 formed between the two retreated portions 21, which is not formed with the semi-insulating layer 11 by the semi-insulating layer forming step. The method for manufacturing another semiconductor laser of the fifth embodiment can manufacture a semiconductor laser 100 having a semi-insulating layer 11 on the outer edge of the side away from the ridge portion 50 having the active layer 3 and opposite to the n-type semiconductor substrate 1 in the x direction, so that when mounted from the surface side electrode (anode electrode 12) side, it is possible to suppress leakage current that does not contribute to laser oscillation and achieve excellent heat dissipation.

[0129] In addition, the present application describes various illustrative embodiments and examples, but the various features, methods, and functions described in one or more embodiments are not limited to the application of a specific embodiment, and can be applied to the embodiment alone or in various combinations. Therefore, countless unillustrated variations are envisioned within the technical scope disclosed in the present application specification. For example, there are cases where at least one constituent element is deformed, added, or omitted, or even at least one constituent element is extracted and combined with constituent elements of other embodiments.

[0130] Description of Reference Numerals

[0131] 1…n-type semiconductor substrate, 2…n-type cladding layer, 3…active layer, 4…p-type first cladding layer, 5…ridge, 6…p-type first buried layer, 7…second buried layer, 8…n-type third buried layer, 9…p-type second cladding layer, 10…p-type contact layer, 11…semi-insulating layer, 12…anode electrode (surface-side electrode), 14…connecting member, 15…insulating film, 16…n-type diffusion barrier layer, 17…heat sink, 18…convex portion, 19…groove, 21…recessed portion, 22…bottom portion, 23…bottom portion, 25…buried layer, 29a, 29b…end portions in the x-direction, 44…active layer surface position, 46…groove first side surface, 47…groove second side surface, 48…recessed portion side surface, 50…ridge, 100…semiconductor laser, 200…semiconductor laser device

Claims

1. A semiconductor laser, characterized in that: The invention comprises: a ridge formed on an n-type semiconductor substrate, and a buried layer buried so as to cover both sides opposed to each other in a direction perpendicular to the extending direction of the ridge, wherein the semiconductor laser is mounted on a surface on a side protruding from the ridge, The direction in which the ridge protrudes from the surface side of the n-type semiconductor substrate is defined as the z direction, the extending direction in which the ridge extends is defined as the y direction, and the direction perpendicular to the z direction and the y direction is defined as the x direction. The ridge includes an n-type cladding layer, an active layer, and a p-type first cladding layer formed in order from the n-type semiconductor substrate side. The buried layer includes: a p-type first buried layer, a second buried layer, and an n-type third buried layer, which are in contact with the side surface of the ridge on the positive side in the x direction and the side surface on the negative side in the x direction. The semiconductor laser comprises: On the positive side of the ridge in the z direction and on the positive side of the n-type third buried layer in the z direction, a p-type second cladding layer and a p-type contact layer are sequentially formed from the n-type semiconductor substrate side; a surface-side electrode connected to the p-type contact layer; as well as a semi-insulating layer formed at an outer edge away from a ridge portion along the x direction, wherein the ridge portion includes: the ridge and the p-type first buried layer in contact with the two side surfaces of the ridge, The semi-insulating layer or the surface-side electrode is formed on the positive side in the z direction at the end side in the x direction of the semiconductor laser.

2. The semiconductor laser according to claim 1, characterized in that A groove extending in the y direction is provided between the side surface on the positive side in the x direction of the ridge and the end on the positive side in the x direction of the semiconductor laser, and between the side surface on the negative side in the x direction of the ridge and the end on the negative side in the x direction of the semiconductor laser. Each of the trenches penetrates the p-type contact layer, the p-type second cladding layer, and the n-type third buried layer. The bottom of the trench is located at the same position as the positive side of the active layer in the second buried layer in the z direction, that is, the surface of the active layer, or the bottom of the trench is located farther from the n-type semiconductor substrate than the surface of the active layer in the second buried layer. The surface-side electrode is connected to the p-type contact layer formed in the convex portion between the two grooves. The side surface of the groove in the x direction which is away from the convex portion is defined as a first side surface of the groove, and the side surface of the groove in the x direction which is closer to the convex portion than the first side surface of the groove is defined as a second side surface of the groove, The semi-insulating layer is formed at a position on the positive side in the z direction of the p-type contact layer from the trench first side surface of the trench to an end in the x direction on the side opposite to the protrusion of the semiconductor laser.

3. The semiconductor laser according to claim 2, characterized in that An insulating film is provided on the inner surface of the trench.

4. The semiconductor laser according to claim 2, characterized in that An insulating film is provided on the first side surface of the trench and the second side surface of the trench, The surface-side electrode covers the insulating film on the first side surface of the trench and the second side surface of the trench and the bottom of the trench.

5. The semiconductor laser according to claim 1, characterized in that A groove extending in the y direction is provided between the side surface on the positive side in the x direction of the ridge and the end on the positive side in the x direction of the semiconductor laser, and between the side surface on the negative side in the x direction of the ridge and the end on the negative side in the x direction of the semiconductor laser. Each of the trenches penetrates the p-type contact layer, and the bottom of the trench is arranged at any position in the z direction from the p-type second cladding layer to the inside of the n-type semiconductor substrate. The surface-side electrode is connected to the p-type contact layer formed in the convex portion between the two grooves. The side surface of the groove in the x direction which is away from the convex portion is defined as a first side surface of the groove, and the side surface of the groove in the x direction which is closer to the convex portion than the first side surface of the groove is defined as a second side surface of the groove, The semi-insulating layer is formed directly or via an n-type diffusion barrier layer on the positive side of the p-type contact layer in the z direction from the inner surface of the trench and the first side surface of the trench to the end of the semiconductor laser in the x direction on the side opposite to the protrusion.

6. The semiconductor laser according to claim 1, characterized in that A retreat portion extending in the y direction is provided between the side surface on the positive side in the x direction of the ridge portion and the end portion on the positive side in the x direction of the semiconductor laser, and between the side surface on the negative side in the x direction of the ridge portion and the end portion on the negative side in the x direction of the semiconductor laser, respectively. The p-type contact layer is removed from each of the retreated portions, and the bottom of the retreated portion is arranged at any position in the z direction from the p-type second cladding layer to the inside of the n-type semiconductor substrate. The surface-side electrode is connected to the p-type contact layer formed in the convex portion between the two receding portions. The semi-insulating layer is formed directly or via an n-type diffusion barrier layer on the side surface and the bottom of the receding portion on the positive side in the x-direction and on the side surface and the bottom of the receding portion on the negative side in the x-direction.

7. The semiconductor laser according to claim 1, characterized in that The surface-side electrode covers the positive side of the semi-insulating layer in the z direction at the positive side in the z direction of the end side in the x direction of the semiconductor laser.

8. The semiconductor laser according to any one of claims 2 to 6, characterized in that: The semi-insulating layer is not covered by the surface-side electrode at an end side of the semiconductor laser in the x direction.

9. A semiconductor laser device, characterized in that: A method comprising: a semiconductor laser according to any one of claims 1 to 8, and a heat sink, The positive side of the semiconductor laser in the z direction, where the surface-side electrode is formed, is connected to the heat sink via a connecting member.

10. A method for manufacturing a semiconductor laser, comprising: The semiconductor laser comprises: a ridge formed on an n-type semiconductor substrate, and a buried layer buried so as to cover both sides of the ridge facing each other in a direction perpendicular to the extending direction of the ridge. The direction in which the ridge protrudes from the surface side of the n-type semiconductor substrate is defined as the z direction, the extending direction in which the ridge extends is defined as the y direction, and the direction perpendicular to the z direction and the y direction is defined as the x direction. The manufacturing method of the semiconductor laser comprises the following steps: A ridge forming step of sequentially forming an n-type cladding layer, an active layer, and a p-type first cladding layer on the n-type semiconductor substrate, and etching to a position lower than the n-type semiconductor substrate side of the active layer, i.e., the negative side in the z direction, to form the ridge having the n-type cladding layer, the active layer, and the p-type first cladding layer exposed on the side surface on the positive side in the x direction and the side surface on the negative side in the x direction; A burying step of forming a p-type first buried layer on the side surface of the ridge on the positive side in the x direction and the side surface on the negative side in the x direction, and burying the ridge to a position higher than the positive side position of the active layer in the z direction, that is, the surface position of the active layer, by sequentially forming a second buried layer and an n-type third buried layer; A lamination step of sequentially forming a p-type second cladding layer, a p-type contact layer, and a semi-insulating layer on the positive side of the ridge in the z direction and on the positive side of the n-type third buried layer in the z direction; A contact layer exposing step of etching the semi-insulating layer in the x-direction region including a ridge portion to expose the p-type contact layer, wherein the ridge portion includes: the ridge and the p-type first buried layer in contact with the two side surfaces of the ridge; as well as The surface-side electrode forming step forms a surface-side electrode on the exposed p-type contact layer, the positive side of the semi-insulating layer in the z direction, and the side surface on the ridge portion side.

11. A method for manufacturing a semiconductor laser, comprising: The semiconductor laser comprises: a ridge formed on an n-type semiconductor substrate, and a buried layer buried so as to cover both sides of the ridge facing each other in a direction perpendicular to the extending direction of the ridge. The direction in which the ridge protrudes from the surface side of the n-type semiconductor substrate is defined as the z direction, the extending direction in which the ridge extends is defined as the y direction, and the direction perpendicular to the z direction and the y direction is defined as the x direction. The manufacturing method of the semiconductor laser comprises the following steps: A ridge forming step of sequentially forming an n-type cladding layer, an active layer, and a p-type first cladding layer on the n-type semiconductor substrate, and etching to a position lower than the n-type semiconductor substrate side of the active layer, i.e., the negative side in the z direction, to form the ridge having the n-type cladding layer, the active layer, and the p-type first cladding layer, with the side surface on the positive side in the x direction and the side surface on the negative side in the x direction exposed; A burying step of forming a p-type first buried layer on the side surface of the ridge on the positive side in the x direction and the side surface on the negative side in the x direction, and burying the ridge to a position higher than the positive side position of the active layer in the z direction, that is, the surface position of the active layer, by sequentially forming a second buried layer and an n-type third buried layer; A lamination step of sequentially forming a p-type second cladding layer, a p-type contact layer, and a semi-insulating layer on the positive side of the ridge in the z direction and on the positive side of the n-type third buried layer in the z direction; A groove forming step of forming grooves at two outer edges away from the ridge portion including the ridge and the p-type first buried layer in contact with the two side surfaces of the ridge toward the positive side and the negative side of the x-direction, wherein the groove penetrates the semi-insulating layer, the p-type contact layer, the p-type second cladding layer, and the n-type third buried layer, and the position of the bottom in the z-direction is the same as the active layer surface position of the active layer in the second buried layer or is located on the positive side of the active layer surface position; a contact layer exposing step of etching the semi-insulating layer formed in a convex portion between the two grooves to expose the p-type contact layer; an insulating film forming step of forming an insulating film on both side surfaces of each of the trenches in the x direction; as well as The front surface electrode forming step forms a front surface electrode so as to cover the p-type contact layer of the protrusion on which the insulating film is not formed in the insulating film forming step.

12. The method for manufacturing a semiconductor laser according to claim 11, characterized in that: In the insulating film forming step, the insulating film is also formed on the bottom of each of the trenches.

13. The method for manufacturing a semiconductor laser according to claim 11, characterized in that: In the surface-side electrode forming step, the surface-side electrode covers the insulating film on the both side surfaces of the trench and the bottom of the trench.

14. A method for manufacturing a semiconductor laser, comprising: The semiconductor laser comprises: a ridge formed on an n-type semiconductor substrate, and a buried layer buried so as to cover both sides of the ridge facing each other in a direction perpendicular to the extending direction of the ridge. The direction in which the ridge protrudes from the surface side of the n-type semiconductor substrate is defined as the z direction, the extending direction in which the ridge extends is defined as the y direction, and the direction perpendicular to the z direction and the y direction is defined as the x direction. The manufacturing method of the semiconductor laser comprises the following steps: A ridge forming step of sequentially forming an n-type cladding layer, an active layer, and a p-type first cladding layer on the n-type semiconductor substrate, and etching to a position lower than the n-type semiconductor substrate side of the active layer, i.e., the negative side in the z direction, to form the ridge having the n-type cladding layer, the active layer, and the p-type first cladding layer exposed on the side surface on the positive side in the x direction and the side surface on the negative side in the x direction; A burying step of forming a p-type first buried layer on the side surface of the ridge on the positive side in the x direction and the side surface on the negative side in the x direction, and burying the ridge to a position higher than the positive side position of the active layer in the z direction, that is, the surface position of the active layer, by sequentially forming a second buried layer and an n-type third buried layer; a lamination step of sequentially forming a p-type second cladding layer and a p-type contact layer on the positive side of the ridge in the z direction and on the positive side of the n-type third buried layer in the z direction; A groove forming step of etching the p-type contact layer at two outer edges away from the ridge portion including the ridge and the p-type first buried layer in contact with the two side surfaces of the ridge toward the positive side and the negative side of the x-direction to form a groove whose bottom position in the z-direction is etched to any position in the z-direction from the p-type second cladding layer to the inside of the n-type semiconductor substrate; a semi-insulating layer forming step of forming a semi-insulating layer directly or via an n-type diffusion barrier layer on the positive side in the z direction of the p-type contact layer outside the trench and on the inner surfaces of the two trenches, away from the convex portion formed between the two trenches in the x direction; as well as The surface-side electrode forming step forms a surface-side electrode so as to cover the p-type contact layer of the protrusion on which the semi-insulating layer is not formed in the semi-insulating layer forming step.

15. A method for manufacturing a semiconductor laser, comprising: The semiconductor laser comprises: a ridge formed on an n-type semiconductor substrate, and a buried layer buried so as to cover both sides of the ridge facing each other in a direction perpendicular to the extending direction of the ridge. The direction in which the ridge protrudes from the surface side of the n-type semiconductor substrate is defined as the z direction, the extending direction in which the ridge extends is defined as the y direction, and the direction perpendicular to the z direction and the y direction is defined as the x direction. The manufacturing method of the semiconductor laser comprises the following steps: A ridge forming step of sequentially forming an n-type cladding layer, an active layer, and a p-type first cladding layer on the n-type semiconductor substrate, and etching to a position lower than the n-type semiconductor substrate side of the active layer, i.e., the negative side in the z direction, to form the ridge having the n-type cladding layer, the active layer, and the p-type first cladding layer exposed on the side surface on the positive side in the x direction and the side surface on the negative side in the x direction; A burying step of forming a p-type first buried layer on the side surface of the ridge on the positive side in the x direction and the side surface on the negative side in the x direction, and burying the ridge to a position higher than the positive side position of the active layer in the z direction, that is, the surface position of the active layer, by sequentially forming a second buried layer and an n-type third buried layer; a lamination step of sequentially forming a p-type second cladding layer and a p-type contact layer on the positive side of the ridge in the z direction and on the positive side of the n-type third buried layer in the z direction; A step of forming a receding portion, etching the p-type contact layer at two outer edges away from the ridge portion including the ridge and the p-type first buried layer in contact with the two side surfaces of the ridge toward the positive side and the negative side in the x-direction, so as to form a receding portion whose bottom position in the z-direction is etched to an arbitrary position in the z-direction from the p-type second cladding layer to the inside of the n-type semiconductor substrate; a semi-insulating layer forming step of forming a semi-insulating layer directly or via an n-type diffusion barrier layer on the side surface and the bottom of the retreated portion on the positive side of the x-direction and the side surface and the bottom of the retreated portion on the negative side of the x-direction; and The surface-side electrode forming step forms a surface-side electrode so as to cover the p-type contact layer of the convex portion formed between the two receding portions, which is not formed with the semi-insulating layer in the semi-insulating layer forming step.

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