Vertical-cavity surface-emitting laser

Abstract

To provide a vertical resonance type surface emission laser which can be operated in a wider band.SOLUTION: A vertical resonance type surface emission laser comprises: a post extended along a first axis; and an electrode surrounding the first axis. The post comprises a first distribution bragg reflector, an activation layer, and a second distribution bragg reflector. The second distribution bragg reflector includes a semiconductor region, a first high resistance region, and a second high resistance region. The first high resistance region and the second high resistance region surround the semiconductor region.The second high resistance region is positioned farther away from the first high resistance region from an upper surface of the post in a direction of the first axis. The first high resistance region includes an inner edge positioned farther away from the first axis from an inner edge of the electrode to a direction orthogonal to the first axis. The second high resistance region includes an inner edge positioned nearer to the first axis than the inner edge of the electrode in the direction orthogonal to the first axis. The high resistance region and the second high resistance region include a first thickness and a second thickness, respectively. The second thickness is larger than the first thickness.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to vertical-cavity surface-emitting lasers. [Background technology]

[0002] Patent Document 1 discloses a vertical-cavity surface-emitting laser including a substrate, a lower distributed Bragg reflector provided on the substrate, an active layer provided on the lower distributed Bragg reflector, and an upper distributed Bragg reflector provided on the active layer. The vertical-cavity surface-emitting laser includes a light-emitting region including the active layer and a high-resistance region located around the light-emitting region. The high-resistance region extends from the top surface of the upper distributed Bragg reflector to the active layer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2002-111051 A Summary of the Invention [Problem to be solved by the invention]

[0004] When the high resistance region is expanded inward to reduce the light emitting region, the capacitance of the upper distributed Bragg reflector is reduced. As the capacitance is reduced, the bandwidth of the vertical-cavity surface-emitting laser tends to be wider. On the other hand, when the high resistance region is expanded inward to reduce the light emitting region, the electrical resistance of the upper distributed Bragg reflector is increased. As the electrical resistance increases, the bandwidth of the vertical-cavity surface-emitting laser tends to be narrower. Thus, there is a trade-off between capacitance and electrical resistance. As a result, there is a limit to how much the bandwidth of the vertical-cavity surface-emitting laser can be improved.

[0005] The present disclosure provides a vertical-cavity surface-emitting laser capable of operating over a wider bandwidth. [Means for solving the problem]

[0006] A vertical cavity surface emitting laser according to one aspect of the present disclosure includes a post provided on a principal surface of a substrate and extending along a first axis intersecting the principal surface of the substrate, and an electrode provided on an upper surface of the post and surrounding the first axis, the post including a first distributed Bragg reflector, an active layer, and a second distributed Bragg reflector, the substrate, the first distributed Bragg reflector, the active layer, and the second distributed Bragg reflector being sequentially arranged in a direction of the first axis, the second distributed Bragg reflector including a semiconductor region, a first high resistance region, and a second high resistance region, the first high resistance region and the second high resistance region having a higher electrical resistance than an electrical resistance of the semiconductor region, the first axis being aligned along a front surface of the substrate, the first high resistance region and the second high resistance region pass through the semiconductor region, surrounding the semiconductor region, the second high resistance region being located farther from the top surface of the post in the direction of the first axis than the first high resistance region, the first high resistance region having an inner edge located farther from the first axis than the inner edge of the electrode in a direction perpendicular to the first axis, the second high resistance region having an inner edge located closer to the first axis than the inner edge of the electrode in a direction perpendicular to the first axis, the first high resistance region and the second high resistance region respectively having a first thickness and a second thickness along the direction of the first axis, and the second thickness being greater than the first thickness. Effect of the Invention

[0007] According to the present disclosure, a vertical-cavity surface-emitting laser capable of operating over a wider bandwidth is provided. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a cross-sectional view illustrating a vertical-cavity surface-emitting laser according to an embodiment. [Diagram 2] FIG. 2 is an enlarged cross-sectional view showing a portion of the vertical-cavity surface-emitting laser of FIG. [Diagram 3] FIG. 3 is a plan view showing a portion of the vertical-cavity surface-emitting laser of FIG. [Figure 4]FIG. 4 is a graph showing an example of the relationship between the depth from the top surface of the post and the proton concentration in a first region of the top surface of the post. [Diagram 5] FIG. 5 is a graph showing an example of the relationship between the depth from the top surface of the post and the proton concentration in the second region of the top surface of the post. [Figure 6] FIG. 6 is a cross-sectional view showing a step of a method for manufacturing a vertical-cavity surface-emitting laser according to an embodiment. [Figure 7] FIG. 7 is a cross-sectional view showing a step of a method for manufacturing a vertical-cavity surface-emitting laser according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] [Description of the embodiments of the present disclosure] A vertical cavity surface emitting laser according to one embodiment includes a post provided on a principal surface of a substrate and extending along a first axis intersecting the principal surface of the substrate, and an electrode provided on an upper surface of the post and surrounding the first axis, the post including a first distributed Bragg reflector, an active layer, and a second distributed Bragg reflector, the substrate, the first distributed Bragg reflector, the active layer, and the second distributed Bragg reflector being sequentially arranged in a direction of the first axis, the second distributed Bragg reflector including a semiconductor region, a first high resistance region, and a second high resistance region, the first high resistance region and the second high resistance region having a higher electrical resistance than an electrical resistance of the semiconductor region, and the first axis is a distance from the first distributed Bragg reflector to the first distributed Bragg reflector. the first high resistance region and the second high resistance region pass through a semiconductor region, surrounding the semiconductor region, the second high resistance region being located farther from the top surface of the post in the direction of the first axis than the first high resistance region, the first high resistance region having an inner edge located farther from the first axis than the inner edge of the electrode in a direction perpendicular to the first axis, the second high resistance region having an inner edge located closer to the first axis than the inner edge of the electrode in a direction perpendicular to the first axis, the first high resistance region and the second high resistance region respectively having a first thickness and a second thickness along the direction of the first axis, the second thickness being greater than the first thickness.

[0010] In the vertical-cavity surface-emitting laser, the capacitance of the second distributed Bragg reflector can be reduced by increasing the second thickness of the second high-resistance region and moving the inner edge of the second high-resistance region closer to the first axis. On the other hand, the electrical resistance of the second distributed Bragg reflector can be reduced by moving the inner edge of the first high-resistance region closer to the electrode away from the first axis. Therefore, the vertical-cavity surface-emitting laser can operate in a wider band.

[0011] The inner edge of the first high resistance region may be located farther from the first axis than the outer edge of the electrode in a direction perpendicular to the first axis, thereby further reducing the electrical resistance of the second distributed Bragg reflector.

[0012] The first and second high resistance regions may each contain protons, and a peak concentration of the protons in the first high resistance region may be greater than a peak concentration of the protons in the second high resistance region, in which case the electrical resistance of the first high resistance region can be made higher.

[0013] The post may include a current confinement layer disposed between the active layer and the second distributed Bragg reflector, the current confinement layer may include an aperture portion and an oxide portion surrounding the aperture portion, the first axis may pass through the aperture portion, and the inner edge of the second high-resistance region may be located farther from the first axis than the inner edge of the oxide portion in a direction perpendicular to the first axis. In this case, an increase in the electrical resistance of the second distributed Bragg reflector can be suppressed.

[0014] [Details of the embodiment of the present disclosure] Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same or equivalent elements are designated by the same reference numerals, and duplicated descriptions are omitted. XYZ coordinate axes are shown in the drawings as necessary. The X-axis, Y-axis, and Z-axis intersect (for example, are perpendicular to) each other.

[0015] FIG. 1 is a cross-sectional view showing a schematic diagram of a vertical-cavity surface-emitting laser according to an embodiment. FIG. 2 is an enlarged cross-sectional view showing a part of the vertical-cavity surface-emitting laser of FIG. 1. FIG. 3 is a plan view showing a part of the vertical-cavity surface-emitting laser of FIG. 1. A vertical-cavity surface-emitting laser (VCSEL) 10 shown in FIG. 1 includes a post PS provided on a main surface 12a of a substrate 12 and an electrode 30 provided on an upper surface PSa of the post PS. The post PS extends along a first axis Ax1 intersecting the main surface 12a of the substrate 12. The direction in which the first axis Ax1 extends coincides with the Z-axis. The electrode 30 surrounds the first axis Ax1. The electrode 30 is, for example, a ring-shaped electrode.

[0016] The substrate 12 has a primary surface 12a including a III-V compound semiconductor. The substrate 12 may be a III-V compound semiconductor substrate. The substrate 12 may be a substrate including a III-V compound semiconductor layer and a base substrate. The III-V compound semiconductor layer has a primary surface 12a. The base substrate supports the III-V compound semiconductor layer. The III-V compound semiconductor includes, for example, GaAs.

[0017] The post PS includes a first distributed Bragg reflector 18, an active layer 20, and a second distributed Bragg reflector 22. The substrate 12, the first distributed Bragg reflector 18, the active layer 20, and the second distributed Bragg reflector 22 are sequentially arranged in the direction of a first axis Ax.

[0018] The first distributed Bragg reflector 18 has a semiconductor laminate structure of a first conductivity type (e.g., n-type). The semiconductor laminate structure includes semiconductor layers 18a and 18b arranged alternately in the direction of the first axis Ax1. The semiconductor layers 18a and 18b have refractive indices different from each other. The semiconductor layer 18a has a refractive index lower than that of the semiconductor layer 18b, for example. Each of the semiconductor layers 18a and 18b includes a III-V compound semiconductor, such as AlGaAs. An example of an n-type dopant is silicon.

[0019] The active layer 20 has, for example, a multiple quantum well structure. The multiple quantum well structure may include GaAs layers (or AlGaAs layers) and AlGaAs layers arranged alternately along the first axis Ax1.

[0020] The second distributed Bragg reflector 22 has a semiconductor laminate structure of a second conductivity type (e.g., p-type). The second conductivity type is opposite to the first conductivity type. The semiconductor laminate structure includes semiconductor layers 22a and 22b arranged alternately in the direction of the first axis Ax1. The semiconductor layers 22a and 22b have refractive indices different from each other. The semiconductor layer 22a has a refractive index lower than that of the semiconductor layer 22b, for example. Each of the semiconductor layers 22a and 22b includes a III-V compound semiconductor, such as AlGaAs.

[0021] A contact layer 29 of a second conductivity type (e.g., p-type) may be provided on the second distributed Bragg reflector 22. The contact layer 29 has an upper surface PSa of the post PS. The contact layer 29 includes a III-V compound semiconductor such as AlGaAs.

[0022] The post PS may include a current confinement layer 26 disposed between the active layer 20 and the second distributed Bragg reflector 22. The current confinement layer 26 includes an aperture portion 26a and an oxide portion 26b surrounding the aperture portion 26a. The first axis Ax1 passes through the aperture portion 26a. The aperture portion 26a is a semiconductor layer of a second conductivity type (e.g., p-type). The aperture portion 26a includes a III-V compound semiconductor including aluminum as a group III element. The aperture portion 26a includes a III-V compound semiconductor such as AlGaAs. The oxide portion 26b includes an aluminum oxide. The aperture portion 26a has a lower electrical resistance than the oxide portion 26b. A semiconductor layer 22b may be provided between the current confinement layer 26 and the active layer 20.

[0023] A third distributed Bragg reflector 14 may be provided between the substrate 12 and the post PS. The third distributed Bragg reflector 14 has, for example, a semiconductor laminate structure of a first conductivity type (for example, n-type). The semiconductor laminate structure may have an i-type. The semiconductor laminate structure includes a plurality of semiconductor layers alternately arranged in the direction of the first axis Ax1. The plurality of semiconductor layers have refractive indices different from one another. Each semiconductor layer includes, for example, a III-V compound semiconductor such as AlGaAs.

[0024] A contact layer 16 of a first conductivity type (for example, n-type) may be provided between the third distributed Bragg reflector 14 and the post PS. The contact layer 16 includes a III-V compound semiconductor such as AlGaAs.

[0025] The vertical-cavity surface-emitting laser 10 may include a semiconductor laminate structure LM provided on a major surface 12a of a substrate 12. A third distributed Bragg reflector 14 and a contact layer 16 are provided between the substrate 12 and the semiconductor laminate structure LM. The semiconductor laminate structure LM has the same layer structure as the post PS. The semiconductor laminate structure LM and the post PS are arranged in a direction perpendicular to the first axis Ax1 (e.g., the X-axis). A trench TR surrounding the post PS may be formed between the semiconductor laminate structure LM and the post PS. The bottom of the trench TR reaches the contact layer 16.

[0026] An insulating layer 50 may be provided on the semiconductor laminate structure LM, the trench TR, and the post PS. On the upper surface PSa of the post PS, the insulating layer 50 has a first opening 50a. The electrode 30 is provided in the first opening 50a. On the bottom of the trench TR, the insulating layer 50 has a second opening 50b. The electrode 40 is provided in the second opening 50b.

[0027] The electrode 30 is in ohmic contact with the upper surface PSa of the post PS. A wiring 32 may be electrically connected to the electrode 30. The wiring 32 extends from the upper surface PSa of the post PS across the trench TR to the semiconductor laminate structure LM.

[0028] The electrode 40 is in ohmic contact with the contact layer 16. A wiring 42 may be electrically connected to the electrode 40. The wiring 42 extends from the trench TR to the semiconductor laminate structure LM.

[0029] The second distributed Bragg reflector 22 includes a semiconductor region SC, a first high resistance region HR1, and a second high resistance region HR2. The semiconductor region SC includes a semiconductor layer 22a and a semiconductor layer 22b. The first high resistance region HR1 and the second high resistance region HR2 have a higher electrical resistance than the electrical resistance of the semiconductor region SC. The first high resistance region HR1 and the second high resistance region HR2 may each contain protons. The first axis Ax1 passes through the center of the semiconductor region SC. The center of the semiconductor region SC may be the center of gravity of the cross-sectional shape of the semiconductor region SC perpendicular to the first axis Ax1. The first high resistance region HR1 and the second high resistance region HR2 surround the semiconductor region SC and the first axis Ax1. The first high resistance region HR1 and the second high resistance region HR2 are, for example, ring-shaped regions.

[0030] The second high resistance region HR2 is located farther from the upper surface PSa of the post PS in the direction of the first axis Ax1 than the first high resistance region HR1. Specifically, the second high resistance region HR2 is formed at a position deeper from the upper surface PSa than the first high resistance region HR1. The first high resistance region HR1 may be disposed between the upper surface PSa and the second high resistance region HR2 in the direction of the first axis Ax1. The lower portion of the second high resistance region HR2 may contact the upper portion of the first high resistance region HR1.

[0031] The first high resistance region HR1 may be formed in the contact layer 29. The second high resistance region HR2 may be formed in the current confinement layer , the semiconductor layer 22b, the active layer 20 and a part of the first distributed Bragg reflector .

[0032] As shown in Fig. 2 and Fig. 3, the first high resistance region HR1 has an inner edge HR1E located outside the inner edge 30E1 of the electrode 30 when viewed from the direction of the first axis Ax1. That is, the first high resistance region HR1 has an inner edge HR1E located closer to the first axis Ax1 than the inner edge 30E1 of the electrode 30 in a direction perpendicular to the first axis Ax1 (for example, the X-axis). The inner edge HR1E is disposed between the inner edge 30E1 and the first axis Ax1 in a direction perpendicular to the first axis Ax1 (for example, the X-axis). The inner edge HR1E of the first high resistance region HR1 is located outside the outer edge 30E2 of the electrode 30 in Fig. 2 and Fig. 3 when viewed from the direction of the first axis Ax1, but may be located inside the outer edge 30E2 of the electrode 30. That is, the inner edge HR1E of the first high resistance region HR1 is located farther from the first axis Ax1 than the outer edge 30E2 of the electrode 30 in a direction perpendicular to the first axis Ax1 (e.g., the X-axis), but may be located closer to the first axis Ax1 than the outer edge 30E2 of the electrode 30. The outer edge of the first high resistance region HR1 may constitute a side surface of the post PS. The inner diameter D3 of the electrode 30 may be 12 μm or more and 22 μm or less. The outer diameter D4 of the electrode 30 may be 16 μm or more and 26 μm or less. The inner diameter D5 of the first high resistance region HR1 may be 20 μm or more and 30 μm or less.

[0033] The second high-resistance region HR2 has an inner edge HR2E located inside the inner edge 30E1 of the electrode 30 when viewed from the direction of the first axis Ax1. That is, the second high-resistance region HR has an inner edge HR2E located closer to the first axis Ax1 than the inner edge 30E1 of the electrode 30 in a direction perpendicular to the first axis Ax1 (for example, the X-axis). The inner edge HR2E of the second high-resistance region HR2 may be located outside the inner edge 26bE of the oxidized portion 26b when viewed from the direction of the first axis Ax1. That is, the inner edge HR2E of the second high-resistance region HR2 may be located farther from the first axis Ax1 than the inner edge 26bE of the oxidized portion 26b in a direction perpendicular to the first axis Ax1 (for example, the X-axis). The outer edge of the second high-resistance region HR2 may form a side surface of the post PS. The inner diameter D1 of the oxidized portion 26b (the outer diameter of the aperture portion 26a) may be 7 μm or more and 9 μm or less. The inner diameter D2 of the second high resistance region HR2 may be not less than 10 μm and not more than 15 μm.

[0034] The first high-resistance region HR1 and the second high-resistance region HR2 have a first thickness TH1 and a second thickness TH2, respectively, along the direction of the first axis Ax1. The second thickness TH2 is greater than the first thickness TH1. The first thickness TH1 is, for example, not less than 1 μm and not more than 2 μm. The second thickness TH2 is, for example, not less than 3 μm and not more than 5 μm.

[0035] FIG. 4 is a graph showing an example of the relationship between the depth from the top surface of the post and the proton concentration in the first region of the top surface of the post. FIG. 5 is a graph showing an example of the relationship between the depth from the top surface of the post and the proton concentration in the second region of the top surface of the post. In both graphs, the vertical axis indicates the proton concentration. The horizontal axis of the graph in FIG. 4 indicates the depth from the top surface PSa of the post PS in the first region R1 of the top surface PSa of the post PS. As shown in FIG. 3, the first region R1 is a region from the outer edge of the top surface PSa of the post PS to the inner edge HR1E of the first high resistance region HR1 as viewed from the direction of the first axis Ax1. The horizontal axis of the graph in FIG. 5 indicates the depth from the top surface PSa of the post PS in the second region R2 of the top surface PSa of the post PS. As shown in FIG. 3, the second region R2 is a region from the inner edge HR1E of the first high resistance region HR1 to the inner edge HR2E of the second high resistance region HR2 as viewed from the direction of the first axis Ax1. The proton concentration can be measured by scanning a cross section of the post PS including the first axis Ax1 using a scanning capacitance microscope (SCM). As shown in Figures 4 and 5, the proton concentration changes continuously depending on the depth from the upper surface PSa. The change in proton concentration shows multiple peaks where the proton concentration is maximized at a certain depth.

[0036] As shown in the graph of FIG. 4, in the first region R1, a first high-resistance region HR1 is formed from the upper surface PSa of the post PS to a first depth DP1. In the first region R1, a second high-resistance region HR2 is formed from the first depth DP1 to a second depth DP2. The first depth DP1 is equal to the first thickness TH1. The second depth DP2 is equal to the sum of the first thickness TH1 and the second thickness TH2. The proton concentration peak PK1 of the first high-resistance region HR1 may be greater than the proton concentration peak PK2 of the second high-resistance region HR2. The proton concentration peaks PK1 and PK2 are, for example, 1×10 18 cm -3 or more or 1×10 19 cm -3 That is all. In each of the first high-resistance region HR1 and the second high-resistance region HR2, the proton concentration profile may have a plurality of peaks. The proton concentration profile can be adjusted by the energy and the dose during ion implantation.

[0037] 5, in the second region R2, the first high-resistance region HR1 is not formed from the upper surface PSa of the post PS to the first depth DP1. In the second region R2, the second high-resistance region HR2 is formed from the first depth DP1 to the second depth DP2.

[0038] In the vertical-cavity surface-emitting laser 10, when a voltage is applied between the electrode 30 and the electrode 40, a bias current is supplied to the active layer 20 through the current confinement layer 26. This causes laser light L to be emitted in the direction of the first axis Ax.

[0039] According to the vertical-cavity surface-emitting laser 10, the capacitance of the second distributed Bragg reflector 22 can be reduced by increasing the second thickness TH2 of the second high-resistance region HR2 and bringing the inner edge HR2E of the second high-resistance region HR2 closer to the first axis Ax1. On the other hand, the electrical resistance to the bias current passing through the second distributed Bragg reflector 22 can be reduced by moving the inner edge HR1E of the first high-resistance region HR1, which is closer to the electrode 30 in the direction of the first axis Ax1, away from the first axis Ax1. Therefore, the vertical-cavity surface-emitting laser 10 can operate in a wider band. According to the vertical-cavity surface-emitting laser 10, the 3 dB band can be increased.

[0040] When the inner edge HR1E of the first high resistance region HR1 is positioned outside the outer edge 30E2 of the electrode 30, the contact area between the electrode 30 and the upper surface of the semiconductor region SC increases. This reduces the contact resistance, and further reduces the electrical resistance of the second distributed Bragg reflector 22.

[0041] When the peak PK1 of the proton concentration in the first high-resistance region HR1 is larger than the peak PK2 of the proton concentration in the second high-resistance region HR2, the electric resistance of the first high-resistance region HR1 can be made higher.

[0042] When the inner edge HR2E of the second high-resistance region HR2 is located outside the inner edge 26bE of the oxidized portion 26b, an increase in the electrical resistance of the second distributed Bragg reflector 22 can be suppressed.

[0043] 6 and 7 are cross-sectional views showing a step of a method for manufacturing a vertical-cavity surface-emitting laser according to an embodiment. The vertical-cavity surface-emitting laser 10 may be manufactured as follows.

[0044] First, as shown in Fig. 6, a semiconductor laminate SL may be formed on a primary surface 12a of a substrate 12. The semiconductor laminate SL includes a third distributed Bragg reflector 14, a contact layer 16, a first distributed Bragg reflector 18, an active layer 20, a second distributed Bragg reflector 22, and a contact layer 29. The third distributed Bragg reflector 14, the contact layer 16, the first distributed Bragg reflector 18, the active layer 20, the second distributed Bragg reflector 22, and the contact layer 29 are formed in this order on the substrate 12. Each layer is formed by, for example, organometallic vapor phase epitaxy (OMVPE).

[0045] Next, a mask MK1 is formed on the semiconductor laminate SL. The mask MK1 is, for example, a resist mask. The first axis Ax1 passes through the mask MK1. When viewed from the first axis Ax1, the mask MK1 is, for example, circular. In a direction perpendicular to the first axis Ax1, the mask MK1 has the same diameter as the inner diameter D5 of the first high-resistance region HR1. Then, ions are implanted into the semiconductor laminate SL. This forms the first high-resistance region HR1. The ions implanted are, for example, protons. Then, the mask MK1 is removed.

[0046] Next, as shown in FIG. 7, a mask MK2 is formed on the semiconductor laminate SL. The mask MK2 is, for example, a resist mask. The first axis Ax1 passes through the mask MK2. The mask MK2 is, for example, circular when viewed from the first axis Ax1. In a direction perpendicular to the first axis Ax1, the mask MK2 has a diameter smaller than that of the mask MK1. The mask MK2 has a diameter equal to the inner diameter D2 of the second high-resistance region HR2. Then, ions are implanted into the semiconductor laminate SL. As a result, the second high-resistance region HR2 is formed. The ions implanted are, for example, protons. The energy of the ion implantation when forming the second high-resistance region HR2 is greater than the energy of the ion implantation when forming the first high-resistance region HR1. As a result, the second high-resistance region HR2 is formed at a position deeper from the surface of the semiconductor laminate SL than the first high-resistance region HR1 in the direction of the first axis Ax1.

[0047] Next, the trench TR shown in FIG. 1 is formed by, for example, photolithography and etching. As a result, the post PS and the semiconductor laminate structure LM are formed. Then, the side surface of the post PS is oxidized to form the oxidized portion 26b of the current confinement layer 26. Then, the insulating layer 50 is formed. Then, the electrodes 30 and 40 are formed. Then, the wiring 32 and wiring 42 are formed.

[0048] Although the preferred embodiments of the present disclosure have been described in detail above, the present disclosure is not limited to the above-described embodiments. The components of the respective embodiments may be combined in any desired manner.

[0049] For example, in the above embodiment, the first high-resistance region HR1 is formed followed by the second high-resistance region HR2, but the first high-resistance region HR1 may be formed after the second high-resistance region HR2 is formed. In this case, ion implantation is performed using the mask MK2, and then ion implantation is performed using the mask MK1.

[0050] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not by the above meaning, and is intended to include all modifications within the scope and meaning equivalent to the claims. [Explanation of symbols]

[0051] 10...Vertical-cavity surface-emitting laser 12...Substrate 12a…main surface 14…Third distributed Bragg reflector 16…Contact layer 18...first distributed Bragg reflector 18a...Semiconductor layer 18b...Semiconductor layer 20…Active layer 22…Second distributed Bragg reflector 22a...semiconductor layer 22b...semiconductor layer 26...Current confinement layer 26a…Aperture section 26b...Oxidation section 26bE…Inner border 29…Contact layer 30...electrode 30E1…Common law 30E2…Outer edge 32…Wiring 40...Electrode 42…Wiring 50…Insulating layer 50a…First opening 50b…Second opening Ax…1st axis Ax1…1st axis D1...inner diameter (outer diameter of aperture portion 26a) D2…Inner diameter D3…Inner diameter D4…Outer diameter D5…Inner diameter HR1…1st high resistance region HR1E…Inner rim HR2…Second high resistance region HR2E…Inner edge L: Laser light LM…Semiconductor laminated structure MK1…Mask MK2…Mask PK1…Peak PK2…Peak PS…Post PSa…Top surface R1…first area R2…Second area SC: Semiconductor area SL: Semiconductor laminate TR…Trench

Claims

1. a post disposed on a major surface of a substrate and extending along a first axis intersecting the major surface of the substrate; an electrode provided on an upper surface of the post and surrounding the first axis; Equipped with the post comprises a first distributed Bragg reflector, an active layer and a second distributed Bragg reflector; the substrate, the first distributed Bragg reflector, the active layer, and the second distributed Bragg reflector are sequentially arranged in a direction of the first axis; the second distributed Bragg reflector includes a semiconductor region, a first highly resistive region, and a second highly resistive region, the second highly resistive region being also formed in a portion of the first distributed Bragg reflector; the first high resistance region and the second high resistance region have a higher electrical resistance than an electrical resistance of the semiconductor region, the first axis passes through the semiconductor region; the first high resistance region and the second high resistance region surround the semiconductor region, the second high resistance region is located farther from the top surface of the post in the direction of the first axis than the first high resistance region; the first high resistance region has an inner edge located farther from the first axis than an inner edge of the electrode in a direction perpendicular to the first axis, the second high resistance region has an inner edge located closer to the first axis than the inner edge of the electrode in a direction perpendicular to the first axis; the first high resistance region and the second high resistance region have a first thickness and a second thickness along the first axis, respectively, the second thickness being greater than the first thickness; the first high resistance region and the second high resistance region each contain protons, a peak concentration of the protons in the first high resistance region is greater than a peak concentration of the protons in the second high resistance region;

2. 2 . The vertical-cavity surface-emitting laser according to claim 1 , wherein the inner edge of the first high-resistance region is located farther from the first axis than an outer edge of the electrode in a direction perpendicular to the first axis.

3. the post includes a current confinement layer disposed between the active layer and the second distributed Bragg reflector; the current confinement layer includes an aperture portion and an oxidation portion surrounding the aperture portion, the first axis passes through the aperture portion, 3. The vertical-cavity surface-emitting laser according to claim 1, wherein the inner edge of the second high-resistance region is located farther from the first axis than the inner edge of the oxidized portion in a direction perpendicular to the first axis.

Images