JPH1187837A - Semiconductor laser and method of manufacturing the same - Google Patents

Abstract

(57) Abstract: A semiconductor laser and a method of manufacturing the same, when forming an oxide current confinement layer in an edge emission type or surface emitting type semiconductor laser, the depth of oxidation, and therefore the current injection region, is reduced. Ensure that width and diameter can be accurately and reproducibly secured. SOLUTION: A compound semiconductor layer, for example, an n-side cladding layer 2 which is laminated and formed including a p-AlAs easily oxidizable layer 26.
2, SCH layer 23, strained quantum well active layer 24, SCH layer 25, p-AlAs easily oxidizable layer 26, p-side cladding layer 2
7. G introduced so as to extend along both sides of the stripe current injection region 26A in the contact layer 28 and the like.
Oxidation suppression region 2 made of a group III impurity such as a or In
9, a stripe current injection region 26A extending from the outer edge of the p-AlAs easy oxidation layer 26 toward the stripe current injection region 26A and being terminated by the oxidation suppression region 29.
Region 26B made of a compound semiconductor oxide that defines
And

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor laser having a current confinement structure using an oxide and a method for manufacturing the same.

At present, in a surface emitting semiconductor laser,
Extremely low threshold current using an oxide film for current confinement has been realized, and the technology tends to be applied to edge emission type semiconductor lasers,
The present invention intends to disclose a technique for improving the manufacturing yield of an oxide current confinement structure.

[0003]

2. Description of the Related Art FIG. 5 is a fragmentary front view showing an edge emission type semiconductor laser for explaining a conventional technique of an oxide current confinement structure.

In the figure, 1 is a substrate, 2 is a one-conductivity-type side cladding layer, 3 is an active layer, 4 is an oxide current confinement layer, 4A is a current injection region, 5 is an opposite conductivity-type cladding layer, 6 Indicates a contact layer, 7 indicates an electrode of the opposite conductivity type, 8 indicates an electrode of one conductivity type, and L _OX indicates the depth of oxidation.

In this semiconductor laser, a material that is easily oxidized is used for the oxide current confinement layer 4, and the width of the current injection region 4A is controlled depending on the oxidation time.

The technology disclosed in the present invention can improve the performance even when applied to other than the edge emission type semiconductor laser, and the embodiment of the present invention is also applicable to a surface emitting semiconductor laser. So here
A conventional surface-emitting type semiconductor laser will be described.

FIG. 6 is a cutaway side view showing a main part of a surface emitting semiconductor laser having an oxide current confinement structure.

In the figure, 11 is a substrate, 12 is a DBR
((Distributed Bragg refle
ctor) layer, 13 is a resonator layer, 14 is a DBR layer, 15
Reference numeral 16 denotes an electrode, and 12A and 14A denote oxide current confinement layers, respectively.

In the oxide current confinement layer 4 or the oxide current confinement layers 12A and 14A in the conventional semiconductor laser shown in FIGS. Since the width and diameter of the material region are controlled by the oxidation time, the oxidation depth L _ox changes due to the fluctuation of the oxidation temperature or the distribution of the oxidation temperature, so that the reproducibility can be improved. And there is a problem that the device characteristics vary.

[0010]

SUMMARY OF THE INVENTION In the present invention, the edge
When an oxide current confinement layer is formed in an emission type or surface-emitting type semiconductor laser, the depth of oxidation, that is, the width and diameter of a current injection region can be accurately and reproducibly secured.

[0011]

According to the present invention, when an easily oxidizable layer is oxidized by providing a hard-to-oxidize region, that is, an oxidation-suppressing region at the edge of a portion to be a current injection region, the progress of oxidation is suppressed. This is to stop at the oxidation inhibition region and to form a current injection region having an accurate width or diameter with good reproducibility.

As described above, in the semiconductor laser and the method of manufacturing the same according to the present invention, (1) a compound semiconductor layer (for example, the n-side layer) including a semiconductor easily oxidizable layer (for example, the easily oxidizable layer 26) is formed. Cladding layer 22, SCH layer 23, strained quantum well active layer 24, S
Group III introduced so as to extend along both sides of a stripe current injection region (for example, stripe current injection region 26A) in CH layer 25, easy oxidation layer 26, p-side cladding layer 27, contact layer 28, and the like. An oxidation-suppressed region (for example, an oxidation-suppressed region 29) made of an impurity (for example, Ga or In), and extending from the outer edge of the semiconductor easy-to-oxidize layer toward the stripe current injection region and terminated at the oxidation-suppressed region And an insulating region (for example, an insulating region 26B) made of a compound semiconductor oxide that defines the stripe current injection region.

(2) Semiconductor multilayer film reflecting mirror (for example, p-side D
Compound semiconductor layers (for example, n-side DBR layer 42, n-side cladding layer 43, cladding / impurity diffusion suppressing layer 43A, and strained quantum well active layer 4) including the BR layer 46).
4, p-side cladding layer 45, cladding / impurity diffusion suppressing layer 45A, p-side DBR layer 46, DBR / contact layer 46
A) An oxidation inhibition region (for example, an oxidation inhibition region) made of a group III impurity (for example, Ga or In) introduced so as to extend along the periphery of the circular current injection region (for example, the circular current injection region 46B). 47) and a semiconductor oxidizable layer (for example, AlAs) included in the semiconductor multilayer mirror.
An insulating region (for example, insulating region 46C) made of a compound semiconductor oxide extending from the outer edge of the layer toward the circular current injection region and terminating at the oxidation suppression region to define the circular current injection region. Characterized by being provided, or

(3) On a semiconductor substrate of one conductivity type (for example, n-type substrate 21), a semiconductor of opposite conductivity type with a cladding layer (for example, n-side cladding layer 22) and an active layer (for example, strained quantum well active layer 24). Easy oxidation layer (for example, p-type easy oxidation layer 2
6) and a cladding layer of the opposite conductivity type (for example, p-side cladding layer 2)
7) and an opposite conductivity type contact layer (for example, a p-type contact layer 28), and then a group III impurity (for example, Ga or Ga) so as to extend along both sides of a portion where a stripe current injection region is to be formed. In) or the like to form an oxidation-suppressed region (for example, an oxidation-suppressed region 29), and then a mesa layer that reaches at least the underlayer surface of the opposite-conductivity-type semiconductor easily oxidizable layer from the surface of the opposite-conductivity-type contact layer. Performing a step of etching, and then oxidizing a portion from the exposed outer edge of the opposite conductive type semiconductor easily oxidizable layer to the oxidation suppression region to define a stripe current injection region (for example, a stripe current injection region 26A). Or a process is included, or

(4) One conductive type semiconductor multilayer mirror (for example, n-side DBR layer 42) and active layer (for example, strained quantum well layer 44B) are formed on one conductive type semiconductor substrate (for example, n-type substrate 41).
), The opposite conductive type semiconductor multilayer reflector (for example, the p-side DBR layer 46) and the opposite conductive type contact layer (for example, the DBR / contact layer 46).
A), and then a group III impurity (for example, Ga or In) is introduced so as to extend along the periphery of the portion where the circular current injection region is to be formed, thereby forming an oxidation suppression region (for example). Forming, and then performing mesa etching from the surface of the opposite conductivity type contact layer to at least the underlying surface of the opposite conductivity type semiconductor multilayer mirror, and then exposing the opposite conductivity type semiconductor A step of oxidizing a region from the outer edge of the opposite conductivity type semiconductor easily oxidizable layer (for example, an AlAs layer) included in the multilayer mirror to the oxidation suppression region to define a circular current injection region (for example, a circular current injection region 46B); Is included.

Owing to the above measures, the oxidation of the semiconductor easily oxidizable layer is reliably stopped in the oxidation inhibition region formed by the implantation of the group III ions, and the oxidation inhibition for controlling the oxidation is prevented. The accuracy of the ion implantation for forming the region has a great difference in accuracy compared to the case where the oxidation of the oxide current confinement layer is controlled by time, and the reproducibility is extremely good, and the manufacturing yield is improved. I do.

Further, the width and diameter of the current injection region in the semiconductor easily oxidizable layer can be easily selected depending on the mask used for ion implantation for forming the oxidation suppression region. Its implementation is easy.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a cutaway front view showing an essential part of an edge emission type semiconductor laser according to an embodiment of the present invention.

In the figure, 21 is a substrate, 22 is an n-side cladding layer, and 23 is a SCH (separate configuration).
element (heterostructure) layer,
24 is a strained quantum well active layer, 24A is a barrier layer, 24B
Is a quantum well layer, 25 is an SCH layer, 26 is an easily oxidized layer, 2
6A is a stripe current injection region, 26B is an insulating region, 2
7 is a p-side cladding layer, 28 is a contact layer, 29 is an oxidation suppression region, 30 is a passivation film, 31 is a p-side electrode, and 32 is an n-side electrode.

The main data concerning each component of the semiconductor laser shown in FIG. 1 is exemplified as follows.

(1) Substrate 21 Material: n-GaAs Impurity: Si Impurity concentration: 2 × 10 ¹⁸ [cm ^-3 ] Thickness: 100 [μm]

(2) Regarding the n-side cladding layer 22 Material: n-InGaP Impurity: Si Impurity concentration: 2 × 10 ¹⁸ [cm ^-3 ] Thickness: 1 [μm]

(3) Regarding the SCH layer 23 Material: i-AlGaAs Thickness: 100 [nm]

(4) Regarding the strained quantum well active layer 24 ○ The barrier layer 24A material: i-GaAs thickness: 10 [nm] ○ The quantum well layer 24B material: i-InGaAs thickness: 8 [nm]

(5) SCH layer 25 Material: i-AlGaAs Thickness: 100 [nm]

(6) Easy oxidation layer 26 Material: p-AlAs Impurity: Zn Impurity concentration: 1 × 10 ¹⁸ [cm ⁻³ ] Thickness: 10 [nm]

(7) About the p-side cladding layer 27 Material: p-InGaP Impurity: Zn Impurity concentration: 1 × 10 ¹⁸ [cm ^-3 ] Thickness: 1 [μm]

(8) About the contact layer 28 Material: p-GaAs Impurity: Zn Impurity concentration: 2 × 10 ¹⁹ [cm ^-3 ] Thickness: 0.3 [μm]

(9) Oxidation suppression region 29 Implanted ions: Ga Accelerating voltage: 150 [kV] Dose: 1 × 10 ¹³ [cm ⁻² ] Width: 1 [μm] Interval: 1 [μm]

(10) Passivation film 30 Material: SiO ₂ Thickness: 300 [nm]

(11) Regarding the p-side electrode 31 Material: Ti / Pt / Au Thickness: 100 [nm] / 300 [nm] / 3 [μm]

(12) Regarding the n-side electrode 32 Material: AuGe / Au / Au Thickness: 30 [nm] / 150 [nm] / 3 [μm]

FIG. 2 is a fragmentary front view showing the semiconductor laser at a key point in the process for explaining the process of manufacturing the semiconductor laser shown in FIG. 1. Next, FIG. 2 and FIG. An embodiment of the present invention will be described with reference to FIG.

FIG. 2 (A) 2- (1) MBE (Molecular Beam E)
The n-side cladding layer 22, the SCH layer 23, the strained quantum well active layer 24, the SCH layer 25, the oxidizable layer 26, the p-side cladding layer 27, and the contact layer 28 are formed on the substrate 21 by applying the (pitaxy) method. Let it grow. The MBE method applied here is, for example, MOVPE (metalor
ganic vapor phase epitax
y) The method may be substituted.

2- (2) By applying a resist process in the lithography technique, an opening 33A is formed in a portion where two oxidation suppression regions extending in the cavity length direction are to be formed.
Is formed.

Here, the width of the opening 33A is 1 [μm], and the interval between the two openings 33A is 1 [μm].

By applying the 2- (3) ion implantation method, Ga ions are implanted to form an oxidation suppression region 29 reaching from the surface of the contact layer 28 to the surface of the SCH layer 25.

2 (B) 2- (4) The current extending in the cavity length direction is obtained by immersing in the acetone solution to remove the resist film 33 and then applying the resist process again. For example, a width 10 covering the portion where the implantation region is to be formed and the two oxidation suppression regions 29
A [.mu.m] stripe resist film (not shown) is formed.

2- (5) By applying a wet etching method using a Br-based etchant as an etchant, the mesa reaching at least the surface of the SCH layer 25 from the surface of the contact layer 28 using the stripe resist film as a mask.・ Perform etching.

2- (6) The stripe resist film is removed by dipping in an acetone solution, and then the easy oxidation layer 26 is oxidized in a steam atmosphere at a temperature of 400 ° C. supplied by nitrogen bubbling.

Since this oxidation is rapidly delayed in the oxidation-suppressed region 29 into which Ga has been introduced, it can be almost stopped there, and the width of the current injection region 26A can be secured accurately.

FIG. 1 1- (1) The whole is covered with a passivation film 30 by applying the CVD method.

1- (2) The passivation film 30 on the top surface of the mesa is etched by applying a resist process in the lithography technique and a wet etching method using a hydrofluoric acid-based etchant. ,
An opening of a stripe having a width of 10 [μm] is formed.

1- (3) By removing the resist film used as an etching mask of the passivation film 30, and then applying a resist process in lithography, a vacuum deposition method, and a lift-off method, The p-side electrode 31 is formed.

1- (4) CMP (chemical m
The thickness of the substrate 21 is, for example, 100 [μm] by applying the mechanical polishing method.
Polish the back surface to a degree.

1- (5) An n-side electrode 32 is formed on the back surface of the substrate 21 by applying the vacuum evaporation method.

Thereafter, the device is cleaved to complete the device. In this semiconductor laser, as described above, the width of the current injection region 26A is secured as designed, so that all devices have substantially the same characteristics. It is uniform.

FIG. 3 is a sectional side view showing a main part of a surface emitting semiconductor laser according to an embodiment of the present invention. still,
Here, a 0.98 [μm] band surface emitting semiconductor laser using a GaAs-based material is targeted.

In the figure, 41 is a substrate, 42 is an n-side DB
R layer, 43 is an n-side cladding layer, 43A is a cladding and impurity diffusion suppressing layer, 44 is a resonator including an active layer, 44A is a barrier layer, 44B is a strained quantum well layer, 45A is a cladding and impurity diffusion suppressing layer, 45A Is a p-side cladding layer, 46 is a p-side DBR layer, 46A is a DBR / contact layer, 46B is a circular current injection region, 46C is an insulating region, 47 is an oxidation suppression region, 48 is a passivation film, 49 is a p-side electrode, 50
Denotes an anti-reflection film, and 51 denotes an n-side electrode.

The main data concerning each component of the surface emitting semiconductor laser shown in FIG. 3 is as follows.

(1) Substrate 41 Material: n-GaAs Impurity: Si Impurity concentration: 2 × 10 ¹⁸ [cm ⁻³ ] Thickness: 100 [μm]

(2) DBR layer 42 Material: n-GaAs (λ / 4) / n-AlAs (λ /
4) Impurity: Si Impurity concentration: 2 × 10 ¹⁸ [cm ⁻³ ] Number of layers: 22.5 pairs

(3) About the n-side cladding layer 43 Material: n-AlGaAs Impurity: Si Impurity concentration: 1 × 10 ¹⁸ [cm ^-3 ] Thickness: 104.75 [nm]

(4) Cladding and impurity diffusion suppressing layer 43
About A Material: i-AlGaAs Thickness: 30 [nm]

(5) Regarding strained quantum well active layer 44 ○ Barrier layer 44A Material: i-GaAs thickness: 10 [nm] ○ Quantum well layer 44B Material: i-InGaAs Thickness: 8 [nm]

(6) Cladding / impurity diffusion suppressing layer 45
A Material: i-AlGaAs Thickness: 30 [nm]

(7) P-side cladding layer 45 Material: p-AlGaAs Impurity: Be Impurity concentration: 1 × 10 ¹⁸ [cm ^-3 ] Thickness: 104.75 [μm]

(8) DBR layer 46 Material: p-GaAs (λ / 4) / p-AlAs (λ /
4) Impurity: Be Impurity concentration: 2 × 10 ¹⁸ [cm ⁻³ ] Number of layers: 25 pairs

(9) DBR / Contact Layer 46A Material p ⁺ -GaAs Impurity: Be Impurity concentration: 2 × 10 ¹⁹ [cm ^-3 ] Thickness: 50 [nm]

(10) Oxidation-suppressing region 47 Implanted ion: Ga Accelerating voltage: changed from 50 [kV] to 300 [kV] Dose: 1 × 10 ¹³ [cm ⁻² ] Inner diameter: 5 [μm] Outer diameter: 7 [μm] Width: 1 [μm]

(11) About the passivation film 48 Material: SiO ₂ Thickness: 300 [nm]

(12) Regarding the p-side electrode 49 Material: Ti / Pt / Au Thickness: 100 [nm] / 300 [nm] / 3 [μm]

(13) Antireflection film 50 Material: SiN Thickness: λ / 4

(14) About the n-side electrode 51 Material: AuGe / Au / Au Thickness: 30 [nm] / 150 [nm] / 3 [μm]

FIG. 4 is a fragmentary front view showing the surface emitting semiconductor laser at a key point in the process for explaining the process of manufacturing the surface emitting semiconductor laser shown in FIG. 3. Next, FIG. An embodiment of the present invention will be described with reference to FIG.

4 (A) 4- (1) By applying the MBE method, a DBR layer 42, an n-side cladding layer 43, a cladding / impurity diffusion suppressing layer 43A, a strained quantum well active layer are formed on a substrate 41. 44, a cladding layer / impurity diffusion suppressing layer 45A, a p-side cladding layer 45,
The DBR layer 46 and the DBR / contact layer 46A are grown. The MBE method applied here is, for example, MOVPE
You may substitute the law.

4- (2) By applying the resist process in the lithography technique, the inner diameter is 5 [μm] and the outer diameter is 7 [μm] corresponding to the portion where the oxidation suppression region is to be formed.
m], so that a resist film 52 having a circular band-shaped opening 52A having a width of 1 [μm] is formed.

4- (3) By applying the ion implantation method, Ga ions are implanted in the entire depth direction of the DBR layer using the resist film 52 as a mask to form the oxidation suppression region 47.

Referring to FIG. 4B, 4- (4) the resist film 52 is removed by immersion in an acetone solution, and then a resist process is applied again. A diameter covering the areas 47 and extending outwardly thereof, for example 2
A circular resist film (not shown) of about 0 [μm] is formed.

4- (5) At least the surface of the p-side cladding layer 45 from the surface of the DBR / contact layer 46A using the circular resist film as a mask by applying a wet etching method using a Br-based etchant as an etchant. Etching is performed to reach.

4- (6) After removing the circular resist film by immersion in an acetone solution, the semiconductor oxidizable layer in the DBR layer 46 is removed in a steam atmosphere at a temperature of 400 ° C. supplied by nitrogen bubbling. An AlAs layer is oxidized.

This oxidation is also slowed down abruptly in the oxidation-suppressed region 47 into which Ga is introduced, so that it can be almost stopped, and the diameter of the current injection region 46A can be secured accurately.

FIG. 3 3- (1) By applying the CVD method, the entire S
It is covered with a passivation film 48 made of iO ₂ .

3- (2) The passivation film 48 on the top surface of the mesa is etched by applying a resist process in the lithography technique and a wet etching method using a hydrofluoric acid-based etchant. ,
A circular opening having a diameter of 10 [μm] is formed.

3- (3) After removing the resist film used as an etching mask for the passivation film 48, a resist process in lithography, a vacuum deposition method, and a lift-off method are applied. A p-side electrode 49 is formed.

3- (4) By applying the CMP method, the back surface is polished so that the thickness of the substrate 41 becomes, for example, about 100 [μm].

3- (5) The thickness is λ / 4 due to the application of the resist process, the vacuum deposition method, and the lift-off method in the lithography technique.
The anti-reflection film 50 and the n-side electrode 51 are formed.

Thereafter, the device is cleaved to complete the device. In this surface-emitting type semiconductor laser, as described above, the diameter of the current injection region 46B is secured as designed, so that all devices have substantially the same characteristics. It is uniform.

[0079]

In the semiconductor laser obtained according to the present invention, the compound semiconductor layer including the semiconductor oxidizable layer is formed so as to extend along both sides of the stripe current injection region in the compound semiconductor layer. An oxidation-suppressing region made of an introduced group III impurity, and extending from an outer edge of the semiconductor easily oxidizable layer toward the stripe current-injecting region and terminating at the oxidation suppressing region to define the stripe current-injecting region. Or an insulating region made of a compound semiconductor oxide, or introduced so as to extend along the periphery of a circular current injection region in a compound semiconductor layer formed by lamination including a semiconductor multilayer mirror. An oxidation-suppressing region made of a group III impurity, and extending from the outer edge of the semiconductor easily oxidizable layer included in the semiconductor multilayer mirror toward the circular current injection region; Are terminated with stop region and a said circular current injection region defines a compound semiconductor oxide insulating regions.

By adopting the above configuration, the oxidation of the semiconductor easily oxidizable layer is reliably stopped in the oxidation suppression region formed by the implantation of the group III ions, and the oxidation suppression for controlling the oxidation is performed. The accuracy of the ion implantation for forming the region has a great difference in accuracy compared to the case where the oxidation of the oxide current confinement layer is controlled by time, and the reproducibility is extremely good, and the manufacturing yield is improved. I do.

Further, the width and diameter of the current injection region in the semiconductor easily oxidizable layer can be easily selected depending on the mask used for ion implantation for forming the oxidation suppression region. Implementation is easy.

[Brief description of the drawings]

FIG. 1 is a fragmentary front view showing an edge emission type semiconductor laser according to an embodiment of the present invention.

FIG. 2 is a fragmentary front view showing the semiconductor laser in a process step for explaining a process of manufacturing the semiconductor laser shown in FIG. 1;

FIG. 3 is a cutaway side view showing a main part of a surface-emitting type semiconductor laser according to an embodiment of the present invention.

FIG. 4 is a fragmentary front view showing the semiconductor laser at a key step in the process for explaining the step of manufacturing the semiconductor laser shown in FIG. 3;

FIG. 5 is a fragmentary front view showing an edge emission type semiconductor laser for explaining a conventional technique of an oxide current confinement structure.

FIG. 6 is a fragmentary side view showing a surface emitting semiconductor laser having an oxide current confinement structure.

[Explanation of symbols]

 Reference Signs List 21 substrate 22 n-side cladding layer 23 SCH layer 24 strained quantum well active layer 24A barrier layer 24B quantum well layer 25 SCH layer 26 easy oxidation layer 26A stripe current injection region 26B insulating region 27 p-side cladding layer 28 contact layer 29 oxidation prevention region Reference Signs List 30 passivation film 31 p-side electrode 32 n-side electrode

Claims (4)

[Claims] An oxidation-suppressing region comprising a group III impurity introduced so as to extend along both sides of a stripe current injection region in a compound semiconductor layer laminated including an easily oxidizable semiconductor layer; An insulating region made of a compound semiconductor oxide that extends from an outer edge of the semiconductor easy oxidation layer toward the stripe current injection region and is terminated by the oxidation suppression region to define the stripe current injection region. An edge emission type semiconductor laser characterized by the following. 2. An oxidation-suppressing region comprising a Group III impurity introduced so as to extend along the periphery of a circular current injection region in a compound semiconductor layer laminated and including a semiconductor multilayer film reflecting mirror; A compound semiconductor oxide extending from the outer edge of the semiconductor oxidizable layer included in the semiconductor multilayer mirror toward the circular current injection region and terminating at the oxidation suppression region to define the circular current injection region. A surface-emitting type semiconductor laser comprising: an insulating region. 3. A step of laminating a one-conductivity-type cladding layer, an active layer, an opposite-conductivity-type semiconductor easily oxidizable layer, an opposite-conductivity-type cladding layer, and an opposite-conductivity-type contact layer on a one-conduction-type semiconductor substrate; Forming a group III impurity so as to extend along both sides of the portion where the stripe current injection region is to be formed, thereby forming an oxidation suppression region; and then, at least the opposite conductivity type semiconductor from the surface of the opposite conductivity type contact layer. Performing a mesa etching to reach a base surface of the easy oxidation layer, and then oxidize a portion from the outer edge of the exposed opposite conductivity type semiconductor easy oxidation layer to the oxidation suppression region to define a stripe current injection region. And a manufacturing method of the edge emission type semiconductor laser. 4. A step of laminating a one-conductivity-type semiconductor multilayer mirror, a resonator including an active layer, an opposite-conductivity-type semiconductor multilayer reflector, and an opposite-conductivity-type contact layer on a one-conductivity-type semiconductor substrate; Next, a step of forming an oxidation suppression region by introducing a Group III impurity so as to extend along the periphery of the portion where the circular current injection region is to be formed, and then forming at least the opposite conductivity from the surface of the opposite conductivity type contact layer. Performing a mesa etching reaching the base surface of the type semiconductor multilayer reflector; and then suppressing the oxidation from the outer edge of the opposite conductive type semiconductor oxidizable layer included in the exposed opposite type semiconductor multilayer reflector. Oxidizing the region up to the region to define a circular current injection region.