JP5189136B2 - Ridge type semiconductor optical device and method for manufacturing ridge type semiconductor optical device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ridge-type semiconductor optical device having a structure of ensuring a route for directly radiating heat from a cladding layer to an electrode with large heat conductivity and preventing large deterioration in optical device characteristics even on the condition of high operating environment temperature, and to provide a method of manufacturing the same. <P>SOLUTION: A ridge-type semiconductor laser 301 comprises a ridge cladding layer 14 in a ridge stripe shape that is defined by a top surface m of an etching stop layer 33 and a top surface r of the ridge cladding layer 14, and an insulating layer 13 that covers a side surface of the ridge cladding layer 14. A edge P of the insulating layer 13 located on the side surface of the ridge cladding layer 14 is located between the top surface r of the ridge cladding layer 14 and the top surface m of the etching stop layer 33. <P>COPYRIGHT: (C)2012,JPO&amp;INPIT

Description

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

  A ridge-type semiconductor laser is known that achieves both reduction in contact resistance and thermal resistance and high reliability (see, for example, Patent Document 1). As shown in FIG. 1, the ridge type semiconductor laser of Patent Document 1 includes a lower cladding layer 31, an active layer 11, an upper cladding layer 32, an etching stop layer 33 on a semiconductor substrate 12, and a ridge portion provided thereon. A ridge having a cladding layer 14 and a ridge contact layer 15 provided thereon, an insulating layer 13 covering the ridge cladding layer 14, and an electrode layer connected to the ridge contact layer 15 via a barrier metal layer 17 18, the insulating layer 13 has an end portion in the thickness direction of the ridge located between the upper surface and the lower surface of the ridge contact layer 15.

JP 2004-104073 A

There are two routes for radiating the heat generated in the active layer 11 and the ridge cladding layer 14 to the electrode layer 18 having a high thermal conductivity on the upper surface side of the active layer 11 of the ridge semiconductor laser. The first route is a route from the ridge contact layer 15 to the electrode layer 18, and the second route is a route to the electrode layer 18 through the ridge side face 19 and the insulating film 13 in the vicinity of the ridge. However, in the first route of the structure of the ridge type semiconductor laser of Patent Document 1, when the ridge contact layer 15 is InGaAs having a low thermal conductivity (thermal conductivity: 5 W / m · K), the active layer 11 and the ridge The efficiency of radiating the heat generated in the partial cladding layer 14 to the electrode layer 18 (for example, Au: thermal conductivity: 314 W / m · K) having a high thermal conductivity via the ridge contact layer 15 is poor. Further, in the second route, since the thermal conductivity of the insulating layer 13 is smaller than the thermal conductivity of the ridge contact layer 15 (for example, SiO ₂ : thermal conductivity: 1.4 W / m · K), the ridge cladding The heat dissipation efficiency from the ridge side surface 19 of the layer 14 and the insulating film 13 near the ridge to the electrode layer 18 is also poor. As described above, the structure of the ridge type semiconductor laser of Patent Document 1 still has a problem that the heat dissipation efficiency is still poor, and particularly when the operating environment temperature is as high as 85 ° C., the temperature of the laser element due to the heat generation of the laser element itself. However, there is a problem that the laser characteristics such as laser light output and high-speed modulation characteristics deteriorate due to the temperature becoming higher than the use environment temperature.

  Accordingly, the present invention secures a route for directly radiating heat from the cladding layer to the electrode layer having a high thermal conductivity, and prevents the characteristics from greatly degrading even under a high operating environment temperature, and a ridge-type semiconductor optical device having a structure It aims at providing the manufacturing method.

  In order to achieve the above object, a ridge-type semiconductor optical device according to the present invention includes a cladding layer having a high thermal conductivity (for example, InP: thermal conductivity) by retracting the end of the insulating layer on the side surface of the ridge from the upper surface of the cladding layer. 68 W / m · K) and an electrode having high thermal conductivity are in direct contact with each other.

  Specifically, the ridge type semiconductor optical device according to the present invention is formed on an active layer, an etching stop layer, and a surface of the etching stop layer opposite to the side where the active layer is provided, and the etching stop layer A ridge stripe-shaped ridge cladding layer having a bottom side and an upper surface opposite to the etching stop layer side, and an insulating layer covering a side surface of the ridge cladding layer, and located on a side surface of the ridge cladding layer The end of the insulating layer is between the top and bottom of the ridge cladding layer.

  This ridge-type semiconductor optical device has a structure in which the end of the insulating layer is recessed from the upper surface of the cladding layer. For this reason, when the barrier metal layer and the electrode layer are laminated, the clad layer and the electrode layer are in contact with each other through the barrier metal layer, so that heat from the active layer can be radiated to the electrode layer.

  Therefore, the present invention secures a route for directly radiating heat from the clad layer to the electrode layer having a high thermal conductivity, and greatly deteriorates the optical element characteristics such as the light output and the high-speed modulation characteristics even under a high use environment temperature. It is possible to provide a ridge type semiconductor optical device having a structure for preventing the above.

The end portion of the insulating layer of the ridge type semiconductor optical device according to the present invention is a position where the light intensity distribution from the active layer is 1 / e ² or less with respect to the maximum light intensity at the center of the active layer. It is preferable that it exists in.

When the electrode layer, which is a metal, approaches the active layer, the absorption of light into the metal increases and the light output characteristics deteriorate. In order to prevent light from reaching the electrode layer made of metal, in the ridge-type semiconductor optical device, the light intensity is 1 / e ² or less with respect to the maximum light intensity at the center of the active layer in consideration of the light intensity distribution. It is preferable to arrange the end portion of the insulating layer at the position. This ridge-type semiconductor optical device has a structure in which the portion of the side surface of the ridge cladding layer that is included in the light intensity distribution range from the active layer is covered with an insulating layer that absorbs less light to prevent deterioration of the light output characteristics. ing.

  The ridge-type semiconductor optical device according to the present invention includes a ridge contact layer disposed on an upper surface of the ridge cladding layer, and a barrier metal layer covering the insulating layer, the ridge cladding layer, and the ridge contact layer. And an electrode layer covering the barrier metal layer. Since the cladding layer and the electrode layer are in contact with each other through the barrier metal layer, it is possible to prevent the metal atoms of the electrode layer from diffusing into the cladding layer and the active layer, and to dissipate heat from the active layer to the electrode layer. can do.

  A method for manufacturing a ridge-type semiconductor optical device according to the present invention includes a step of forming an active layer, a step of forming an etching stop layer, and a cladding on a surface of the etching stop layer opposite to the side on which the active layer is present. A semiconductor stacking step for sequentially forming a layer and a contact layer, and a ridge stripe forming step for etching the other portions until the etching stop layer is exposed, leaving the ridge cladding layer and the ridge contact layer to be a ridge stripe. An insulating layer forming step of forming an insulating layer on the surface of the semiconductor including the ridge portion cladding layer and the ridge portion contact layer that has become the ridge stripe, and the etching stop layer side of the ridge portion cladding layer as a bottom portion, When the ridge contact layer side of the ridge cladding layer is the top surface, the ridge An insulating layer etching step of etching the insulating layer in order so that an end portion of the insulating layer on a side surface of the lad layer is between the top surface and the bottom portion of the ridge cladding layer. To do.

  With this manufacturing method, the end portion of the insulating layer can be made to recede from the upper surface of the cladding layer. When the barrier metal layer and the electrode layer are laminated, the cladding layer and the electrode layer can be in contact with each other through the barrier metal layer, and metal atoms of the electrode layer are prevented from diffusing into the cladding layer and the active layer. And a ridge type semiconductor optical device capable of dissipating heat from the active layer to the electrode layer.

  Therefore, the present invention secures a route for directly radiating heat from the clad layer to the electrode layer having a high thermal conductivity, and greatly deteriorates the optical element characteristics such as the light output and the high-speed modulation characteristics even under a high use environment temperature. It is possible to provide a method of manufacturing a ridge type semiconductor optical device having a structure for preventing the above.

In the insulating layer etching step of the method for manufacturing a ridge-type semiconductor optical device according to the present invention, an end of the insulating layer on the side surface of the cladding layer has an intensity distribution of light from the active layer. The insulating layer is etched so as to be at a position that is 1 / e ² or less with respect to the maximum light intensity at the center.

  The method for manufacturing a ridge-type semiconductor optical device according to the present invention includes a barrier that covers the insulating layer, the cladding layer, and the contact layer on the side where the ridge stripe is formed in the etching stop layer after the insulating layer etching step. A barrier metal layer forming step for forming a metal layer and an electrode layer forming step for forming an electrode layer covering the barrier metal layer are sequentially performed.

  Further, the barrier metal layer forming step of the method for manufacturing a ridge type semiconductor optical device according to the present invention is characterized in that the barrier metal is obliquely deposited or the barrier metal is attached by a sputtering method.

  In patent document 1, since the coverage of the barrier metal layer on the side surface of the clad layer is incomplete, the insulating layer covers the entire side surface of the clad layer and prevents metal atoms in the electrode layer from diffusing into the clad layer and the active layer. Thus, a reduction in conversion efficiency for converting laser current into light was prevented. In the present invention, coverage of the barrier metal layer can be improved by obliquely depositing the barrier metal layer. For this reason, the present invention eliminates the need to cover all sides of the cladding layer with an insulating layer, and can improve the heat dissipation of the ridge-type semiconductor optical device and prevent the laser conversion efficiency from being lowered.

  The present invention secures a route for directly radiating heat from the cladding layer to the electrode layer having a high thermal conductivity, and prevents the optical element characteristics such as the light output and the high-speed modulation characteristics from being greatly deteriorated even under a high operating environment temperature. It is an object of the present invention to provide a ridge type semiconductor optical device having a structure and a method of manufacturing the same.

It is a figure explaining the structure of the conventional ridge type semiconductor laser. It is a figure explaining the structure of the ridge type semiconductor laser concerning this invention. It is a figure explaining the thermal analysis of the ridge type semiconductor laser which concerns on this invention. It is a figure explaining the heat dissipation of the ridge type semiconductor laser which concerns on this invention. It is a figure explaining the manufacturing method of the ridge type semiconductor laser concerning this invention. It is a figure explaining the structure of the ridge type semiconductor optical modulator concerning this invention.

  Embodiments of the present invention will be described with reference to the accompanying drawings. The embodiments described below are examples of the present invention, and the present invention is not limited to the following embodiments. In the present specification and drawings, the same reference numerals denote the same components.

(First embodiment)
In the first embodiment, a ridge type semiconductor laser will be described as an example of a ridge type semiconductor optical device. FIG. 2 is a diagram illustrating a ridge type semiconductor laser 301 which is an example of the present embodiment. In the ridge type semiconductor laser 301, a lower cladding layer 31, an active layer 11, an upper cladding layer 32, and an etching stop layer 33 are formed in this order on a semiconductor substrate 12, and an upper surface m of the etching stop layer 33 and an upper surface of the ridge portion cladding layer 14. a ridge-strand-shaped ridge-part cladding layer 14 and an insulating layer 13 covering the side surface of the ridge-part cladding layer 14, and an end P of the insulating layer 13 on the side surface of the ridge-part cladding layer 14 is It is between the upper surface r of the partial cladding layer 14 and the upper surface m of the etching stop layer 33. For example, the semiconductor material of the semiconductor substrate 12 and the ridge cladding layer 14 is InP, and the semiconductor materials of the lower cladding layer 31 and the upper cladding layer 32 are InP and AlInGaAs.

  The ridge-type semiconductor laser 301 includes a ridge contact layer 15 disposed on the upper surface of the ridge cladding layer 14, a barrier metal layer 17 covering the insulating layer 13, the ridge cladding layer 14 and the ridge contact layer 15, and a barrier metal. And an electrode layer 18 covering the layer 17. The ridge-type semiconductor laser 301 includes an ohmic electrode 16 on the upper surface of the ridge contact layer 15 and covers the barrier metal layer 17 including the ohmic electrode 16.

  In the ridge-type semiconductor laser 301, the end portion P of the insulating film 13 on the side surface of the ridge portion cladding layer 14 is lowered from the lower surface of the ridge portion contact layer 15 (upper surface r of the ridge portion cladding layer 14). The layer 18 is in contact with the barrier metal layer 15. With this structure, the ridge-type semiconductor laser 301 can secure a route for directly radiating heat from the ridge cladding layer 14 to the electrode layer 18 having a high thermal conductivity, so that the laser light output and high-speed modulation can be achieved even under a high operating environment temperature. Laser characteristics such as characteristics are not greatly deteriorated.

Subsequently, the height d of the end portion P of the insulating film 13 from the center of the active layer 11 will be examined. The relationship between the amount of receding from the upper surface of the ridge contact layer 15 at the end P and the temperature inside the ridge semiconductor laser 301 was simulated by the following thermal analysis model. The structure of the ridge type semiconductor laser is an example of an oscillation wavelength band of 1.3 μm using an InP substrate.
Ridge cladding layer 14: thickness 1.5 μm, bottom m width 1.6 μm, material InP, thermal conductivity 68 W / m · K
Ridge contact layer 15: thickness 0.35 μm, material InGaAs, thermal conductivity 5 W / m · K
Electrode layer 18: thickness 1.0 μm, material Au, thermal conductivity 315 W / m · K
Insulating film 13: Material SiO ₂ , thermal conductivity 1.4 W / m · K
The thickness of the ridge portion cladding layer 14 is the distance from the upper surface m of the etching stop layer 33 to the upper surface r of the ridge portion cladding layer 14. The thicknesses of the ridge contact layer 15 and the electrode layer 18 are the thicknesses in the normal direction of the surface of the semiconductor substrate 12 on the portion of the ridge cladding layer 14. The barrier metal that prevents Au from diffusing into the semiconductor material is a laminate of Ti and Pt. The thermal conductivity of Ti and Pt is sufficiently larger than the thermal conductivity of InGaAs. Since it has no effect, it is omitted in the simulation.

  FIG. 3 is a diagram for explaining a thermal analysis model for performing a simulation. In this thermal analysis model, the ridge type semiconductor laser 301 is arranged on the heat sink 21. The heat sink 21 is made of a material AlN, and is set to 85 ° C. as the environmental temperature of the ridge type semiconductor laser 301. The ridge type semiconductor laser 301 was driven under conditions satisfying the characteristic specifications, and a difference temperature ΔT between the internal temperature of the ridge type semiconductor laser 301 and the heat sink temperature (85 ° C.) was obtained. The position of the end P is gradually retreated from the same position (retraction amount 0 μm) as the top surface of the ridge contact layer 15 (the boundary surface between the ridge contact layer 15 and the ohmic electrode 16), and the retraction amount is 1.5 μm. FIG. 4 shows the result of simulation of the relationship between the differential temperature ΔT and the retreat amount.

  The horizontal axis of the graph in FIG. 4 indicates the amount of receding from the upper surface of the ridge contact layer 15 to the end P of the insulating layer 13. The vertical axis represents the difference temperature ΔT. When the upper surface of the ridge contact layer 15 and the end portion P coincide with each other, that is, when the retreat amount is zero, the difference temperature ΔT is 36 ° C., but the end portion P is the upper surface r of the ridge portion cladding layer 14 (retraction amount 0. When it is 35 μm or less, ΔT decreases rapidly. This indicates that heat is radiated to the electrode layer 18 from the contact portion between the ridge portion cladding layer 14 and the electrode layer 18.

Next, the range of the retraction amount is examined. As the amount of receding increases, ΔT decreases. However, when the amount of receding increases, the barrier metal layer 17 and the electrode layer 18, which absorb large amounts of light, become active layers 11 instead of the insulating layer 13 that hardly absorbs light. It will approach. As a result, the intensity distribution range B of the light generated in the active layer 11 of FIG. 2 reaches the barrier metal layer 17 and the electrode layer 18 and causes a rapid deterioration of the light output characteristics. Therefore, the end portion P of the insulating layer needs to be at a position that is 1 / e ² or less with respect to the maximum light intensity at the center of the active layer 11 in the light intensity distribution from the active layer 11. From the above viewpoint, the end portion P is disposed at a position of 0.8 μm or more in the normal direction of the surface of the etching stop layer 33 from the center of the active layer. If defined by the retraction amount of the end portion P, the limit value is about 1.05 μm.

  That is, the height d of the end portion P is a range in which the light distribution range B does not reach the electrode layer 18 from the upper surface r of the ridge portion cladding layer 14. Specifically, the end portion P is a position where d ≧ 0.8 μm and not more than the upper surface r of the ridge portion cladding layer 14.

  The ridge type semiconductor laser 301 can achieve an effect of about 5 ° C. or more due to a heat dissipation effect in a high temperature region as compared with the semiconductor laser having the structure described in Patent Document 1. In particular, regarding the uncooled high-speed modulation DFB laser element required under the maximum operating temperature condition of 85 ° C., the internal temperature of the ridge-type semiconductor laser is lowered by 5 ° C. or more. Needless to say, this is a very useful technique that can achieve a significant improvement in the laser characteristic yield.

  Next, a method for manufacturing the ridge type semiconductor laser 301 will be described. FIG. 5 is a diagram for explaining the manufacturing method. In this manufacturing method, the lower cladding layer 31, the active layer 11, the upper cladding layer 32, and the etching stop layer 33 are formed on the semiconductor substrate 12, and the ridge cladding layer 14 and the ridge contact layer 15 are formed on the etching stop layer 33. And a ridge stripe forming step of etching the other portions until the surface of the etching stop layer 33 is exposed, leaving the ridge cladding layer 14 and the ridge contact layer 15 in the portions to be ridge stripes. And an insulating layer forming step for forming an insulating layer 13 on the semiconductor surface including the ridge-cladding layer 14 and the ridge-contact layer 15 formed into a ridge stripe, and an end of the insulating layer 13 on the side surface of the ridge-cladding layer 14 The insulating layer is such that P is between the upper surface r and the bottom m of the ridge cladding layer 14. 3 is carried out and the insulating layer etching step of etching, in this order. Further, after the insulating layer etching step, an ohmic electrode forming step for forming an ohmic electrode 16 on the ridge contact layer 15 is performed. For example, if the ohmic electrode 16 is P-type, AuZnNi is laminated.

  The manufacturing method further includes a barrier metal layer forming step of forming a barrier metal layer 17 covering the insulating layer 13, the ridge cladding layer 14, the ridge contact layer 15 and the ohmic electrode 16 after the ohmic electrode forming step, An electrode layer forming step for forming an electrode layer 18 covering the metal layer 17 is sequentially performed.

  FIG. 5 shows an insulating layer etching process, an ohmic electrode forming process, a barrier metal layer forming process, and an electrode layer forming process. For example, a semiconductor lamination process, a ridge stripe forming process, and an insulating layer forming process are performed using a known technique to form the structure shown in (1). Thereafter, (2) resist coating is performed, and (3) a part of the resist film is removed to expose the insulating film 13 on the ridge stripe. (4) and (5) are the insulating layer etching process. First, (4) the insulating film on the ridge stripe is removed by using reactive ion etching (RIE). Subsequently, (5) the insulating film 13 on the side surface of the ridge cladding layer 14 is wet-etched. At this time, the insulating layer 13 is etched so that the end portion P of the insulating layer 13 is between the upper surface r and the bottom m of the ridge portion cladding layer 14 by adjusting the etching time. Specifically, the insulating layer 13 is such that the end portion P is 0.8 μm or more in the normal direction of the surface of the etching stop layer 33 from the center of the active layer 11 and less than or equal to the upper surface r of the ridge portion cladding layer 14. Etch.

  After the insulating layer etching step is completed, (6) the resist is removed, and (7) an ohmic electrode forming step and (8) a barrier metal layer forming step are performed. Here, layers of Ti, Pt, and Au are stacked. In the barrier metal layer forming step, the barrier metal is obliquely deposited. The oblique deposition is preferably performed from a direction in the range of an angle of 30 degrees or more and 55 degrees or less with respect to the normal line of the surface of the semiconductor substrate 12. By performing oblique deposition, the side surfaces of the ridge stripe (the side surfaces of the ridge portion cladding layer 14 and the side surfaces of the insulating film 13 covering the side surfaces of the ridge portion cladding layer 14) can be completely covered, and the coverage of the barrier metal layer is improved. It is possible to prevent the atoms of the electrode layer to be laminated thereafter from diffusing into the ridge cladding layer 14 and the active layer 11.

  Finally, (8) an electrode layer forming step is performed to complete the ridge type semiconductor laser 301. Here, Ti and Au are vapor-deposited.

  In the barrier metal layer forming step, the oblique deposition method has been described, but the barrier metal layer coverage can also be improved by a sputtering method.

  Further, the example in which the ohmic electrode forming process is performed after the insulating layer etching process has been described, but the present invention is applied even when the ohmic electrode process is performed after the semiconductor lamination process and before the ridge stripe forming process. It goes without saying that it can be done.

(Second Embodiment)
Although the embodiment described above is an example of a ridge type semiconductor laser, the element structure and the manufacturing method of the present invention are also applied to a ridge type semiconductor optical modulator having the same structure as the ridge type semiconductor laser. Is possible. In the second embodiment, a ridge type semiconductor optical modulator will be described as an example of a ridge type semiconductor optical device. FIG. 6 is a diagram for explaining a ridge type semiconductor optical modulator 302 which is an example of the present embodiment. In the case of the ridge type semiconductor optical modulator 302, heat is generated in the absorption layer 110 and the ridge portion cladding layer 14 by the photocurrent generated in the absorption layer 110. This heat generation deteriorates the modulation characteristics of the conventional ridge type semiconductor optical modulator. Therefore, the ridge type semiconductor optical modulator to which the structure described with reference to the ridge type semiconductor laser 301 in FIG. 2 is applied, that is, the ridge type semiconductor optical modulator 302 can prevent deterioration of modulation characteristics.

  The manufacturing method of the ridge type semiconductor optical modulator 302 can be explained by the same manufacturing method as that of the ridge type semiconductor laser 301 by replacing the active layer 11 of the ridge type semiconductor laser 301 with the absorption layer 110 of the optical modulator. As described above, the present invention can provide a ridge type semiconductor optical modulator having a structure that prevents the optical modulation characteristics from being greatly deteriorated and a method for manufacturing the same, as in the case of the ridge type semiconductor laser.

  The above explanation is an example in the case of a single element of a ridge type semiconductor laser and a ridge type semiconductor optical modulator. However, the element structure and manufacturing method of the present invention are such that the semiconductor laser and the semiconductor optical modulator are on the same substrate. Needless to say, the present invention can also be applied to an integrated optical device.

11: active layer 12: semiconductor substrate 13: insulating layer 14: ridge cladding layer 15: ridge contact layer 16: ohmic electrode 17: barrier metal layer 18: electrode layer 19: ridge side surface 21: heat sink 31: lower cladding layer 32 : Upper cladding layer 33: etching stop layer 110: absorption layer 301: ridge type semiconductor laser 302: ridge type semiconductor optical modulator

Claims (6)

An active layer,
An etch stop layer;
A ridge-striped ridge cladding layer formed on a surface of the etching stop layer opposite to the side where the active layer is located, with the etching stop layer side as a bottom and the etching stop layer as a top surface; ,
An insulating layer covering a side surface of the ridge portion cladding layer;
A ridge contact layer disposed on an upper surface of the ridge cladding layer;
A barrier metal layer covering the insulating layer, the ridge portion cladding layer and the ridge portion contact layer;
An electrode layer covering the barrier metal layer;
With
The end of the insulating layer, which is located on the side surface of the ridge cladding layer and is adjusted by etching, is normal to the etching stop layer surface from the center of the active layer between the top and bottom of the ridge cladding layer. A ridge-type semiconductor optical device that is 0.8 μm or more in the direction . The end portion of the insulating layer is located at a position where the light intensity distribution from the active layer is 1 / e ² or less with respect to the maximum light intensity at the center of the active layer. A ridge type semiconductor optical device as described in 1. Forming an active layer;
Forming an etching stop layer;
A semiconductor lamination step of sequentially forming a cladding layer and a contact layer on the surface of the etching stop layer opposite to the side on which the active layer is present;
A ridge stripe forming step of leaving a ridge portion cladding layer and a ridge portion contact layer of a portion to be a ridge stripe, and etching other portions until the etching stop layer is exposed;
An insulating layer forming step of forming an insulating layer on the surface of the semiconductor including the ridge portion cladding layer and the ridge portion contact layer that have become the ridge stripe;
When the etching stop layer side of the ridge portion cladding layer is the bottom and the ridge portion contact layer side of the ridge cladding layer is the top surface, the end of the insulating layer on the side surface of the ridge cladding layer is An insulating layer etching step of etching the insulating layer so as to be between the top surface and the bottom of the ridge cladding layer;
A method for manufacturing a ridge-type semiconductor optical device, characterized in that: In the insulating layer etching step, the end portion of the insulating layer on the side surface of the cladding layer is 1 / e ^{2 with} respect to the maximum light intensity at the center of the active layer in the light intensity distribution from the active layer. 4. The method of manufacturing a ridge type semiconductor optical device according to claim 3, wherein the insulating layer is etched so as to be in a position below. After the insulating layer etching step,
A barrier metal layer forming step of forming a barrier metal layer that covers the insulating layer, the ridge cladding layer, and the ridge contact layer on the side of the etching stop layer where the ridge stripe is formed;
An electrode layer forming step of forming an electrode layer covering the barrier metal layer;
5. The method for manufacturing a ridge type semiconductor optical device according to claim 3, wherein the steps are performed in order. In the barrier metal layer forming step,
6. The method of manufacturing a ridge-type semiconductor optical device according to claim 5, wherein the barrier metal is obliquely deposited or the barrier metal is deposited by a sputtering method.

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