阅读说明：本技术 光斑改善型垂直腔面发射激光器及其制作方法 (Light spot improved vertical cavity surface emitting laser and manufacturing method thereof ) 是由 蔡文必 曾评伟 于 2021-09-02 设计创作，主要内容包括：本申请提供一种光斑改善型垂直腔面发射激光器,包括衬底,衬底包括第一区域和位于第一区域周围的第二区域,第二区域的平坦程度小于第一区域。在衬底正面依次形成有N型DBR层、发光层和P型DBR层,P型DBR层中形成有环状的氧化层,第二区域构成的环状内径小于氧化层构成的出光孔径。利用平坦程度较低的第二区域可以弱化对应位置的上下DBR层的光反射,可将出光孔径边缘的强光的光发射减弱,达到改善出光不均匀的问题。此外,本申请还提供一种该激光器的制作方法,通过直接对衬底进行粗糙化形成第二区域的方式,无需额外设置其他层级结构的基础上,达到改善出光不均匀的问题,实现改善最终光斑模态的目的。(The application provides a facula-improved vertical cavity surface emitting laser, which comprises a substrate, wherein the substrate comprises a first area and a second area positioned around the first area, and the flatness degree of the second area is smaller than that of the first area. An N-type DBR layer, a light emitting layer and a P-type DBR layer are sequentially formed on the front surface of the substrate, an annular oxide layer is formed in the P-type DBR layer, and the annular inner diameter formed by the second region is smaller than the light emitting aperture formed by the oxide layer. The light reflection of the upper DBR layer and the lower DBR layer at the corresponding positions can be weakened by the second region with lower flatness, the light emission of strong light at the edge of the light-emitting aperture can be weakened, and the problem of non-uniformity of light emission is solved. In addition, the application also provides a manufacturing method of the laser, and the problem of uneven light emitting is solved and the purpose of improving the final light spot mode is achieved on the basis of not additionally arranging other hierarchical structures by directly roughening the substrate to form the second area.)

1. A spot-improved vertical cavity surface emitting laser, comprising:

the front surface of the substrate is provided with a flat first area and a second area positioned around the first area, the flatness degree of the second area is smaller than that of the first area, and the second area is obtained by roughening the front surface of the substrate;

the N-type DBR layer is arranged on the front surface of the substrate;

the light-emitting layer is arranged on one side, away from the substrate, of the N-type DBR layer;

the P-type DBR layer is arranged on one side, far away from the N-type DBR layer, of the light emitting layer, an annular oxide layer is formed on one side, close to the light emitting layer, of the P-type DBR layer, and the annular inner diameter formed by the second area is smaller than the light emitting aperture formed by the oxide layer;

the contact layer is arranged on one side of the P-type DBR layer, which is far away from the light-emitting layer, and the P electrode is annular;

and the N electrode is arranged on the back surface of the substrate.

2. The spot-improved VCSEL of claim 1, wherein the second region includes a plurality of roughness elements formed by etching an edge region of the substrate to reduce flatness of the edge region, the roughness elements being spaced apart from each other.

3. The spot-improved vertical cavity surface emitting laser according to claim 2, wherein said roughness component is a groove formed on said substrate or a columnar structure formed on said substrate.

4. The spot-improved vertical cavity surface emitting laser according to claim 2, wherein each of said roughness elements has a cross-sectional width of 2.5 μm or less, and a distance between two adjacent roughness elements is 2.5 μm or less.

5. The spot-improved vertical cavity surface emitting laser according to claim 2, wherein a cross-sectional shape of said roughness member is a circle, an ellipse, a square or a polygon.

6. The spot-improved vertical cavity surface emitting laser according to claim 2, wherein an etching depth of each of said roughness features is smaller than a thickness of said substrate.

7. The spot-improved vertical cavity surface emitting laser according to claim 2, wherein the etched position of said substrate is further filled with AlAs.

8. A manufacturing method of a facula-improved vertical cavity surface emitting laser is characterized by comprising the following steps:

providing a substrate;

roughening the edge of the substrate to form a first area and a second area located around the first area, wherein the flatness degree of the second area is smaller than that of the first area;

sequentially forming an N-type DBR layer, a light-emitting layer and a P-type DBR layer on the front surface of the substrate;

performing an oxidation process on one side of the P-type DBR layer close to the light-emitting layer to form an annular oxide layer, wherein the annular inner diameter formed by the second region is smaller than the light-emitting aperture formed by the oxide layer;

forming a contact layer and a ring-shaped P-type electrode on the side of the P-type DBR layer far away from the light-emitting layer;

and forming an N electrode on the back surface of the substrate.

9. The method according to claim 8, wherein the step of roughening the substrate to form a first region and a second region around the first region includes:

coating positive photoresist on the front side of the substrate;

adding the photomask with the holes and carrying out exposure and development treatment to define a plurality of first openings on the edge of the substrate;

and etching the substrate at each first opening to form a first area and a second area around the first area on the substrate, wherein the second area comprises a plurality of grooves arranged at intervals.

10. The method according to claim 8, wherein the step of roughening the substrate to form a first region and a second region around the first region includes:

coating a negative photoresist on the front side of the substrate;

adding the photomask with the holes and carrying out exposure and development treatment to define a plurality of second openings on the edge of the substrate;

and etching the substrate at each second opening to form a first area and a second area around the first area on the substrate, wherein the second area comprises a plurality of columnar structures arranged at intervals.

Technical Field

The invention relates to the technical field of lasers, in particular to a light spot improved vertical cavity surface emitting laser and a manufacturing method thereof.

Background

A Vertical-Cavity Surface-Emitting Laser (VCSEL) can realize Laser emission on the Surface of a chip, and has the advantages of low threshold current, stable single-wavelength operation, easy high-frequency modulation, and the like, so that the VCSEL is widely applied to the fields of optical communication, optical interconnection, optical storage, and the like.

In a conventional VCSEL structure, an oxide layer is generally formed on a P-type DBR layer to achieve the effect of current confinement. Due to the current distribution, the current density near the edge of the oxide layer is the highest and the center of the oxide aperture is lower in the oxide aperture formed by the oxide layer, resulting in uneven current density in the oxide aperture. The current distribution unevenness will affect the VCSEL spot mode and an ideal gaussian mode cannot be obtained. In the prior art, a mode of reducing the oxide aperture is adopted to improve the light spot mode to a certain extent, but the mode causes the current density to rise, and the heat dissipation burden of the device is increased.

Disclosure of Invention

The invention aims to provide a facula-improved vertical cavity surface emitting laser and a manufacturing method thereof, which can improve the problem of uneven light emission of a device and improve the final facula mode.

Embodiments of the invention may be implemented as follows:

in a first aspect, the present invention provides a spot-improved vertical cavity surface emitting laser, including:

the front surface of the substrate is provided with a flat first area and a second area positioned around the first area, the flatness degree of the second area is smaller than that of the first area, and the second area is obtained by roughening the front surface of the substrate;

the N-type DBR layer is arranged on the front surface of the substrate;

the light-emitting layer is arranged on one side, away from the substrate, of the N-type DBR layer;

the P-type DBR layer is arranged on one side, far away from the N-type DBR layer, of the light emitting layer, an annular oxide layer is formed on one side, close to the light emitting layer, of the P-type DBR layer, and the annular inner diameter formed by the second area is smaller than the light emitting aperture formed by the oxide layer;

the contact layer is arranged on one side of the P-type DBR layer, which is far away from the light-emitting layer, and the P electrode is annular;

and the N electrode is arranged on the back surface of the substrate.

In an alternative embodiment, the second region includes a plurality of roughness features formed by etching the edge region of the substrate to reduce the flatness of the edge region, and the roughness features are spaced apart from each other.

In an alternative embodiment, the roughness elements are grooves formed on the substrate or columnar structures formed on the substrate.

In an alternative embodiment, each of the roughness elements has a cross-sectional width of less than or equal to 2.5 microns and the distance between two adjacent roughness elements is less than or equal to 2.5 microns.

In alternative embodiments, the cross-section of the roughness elements is circular, elliptical, square or polygonal in shape.

In an alternative embodiment, the etch depth of each of the roughness elements is less than the thickness of the substrate.

In an alternative embodiment, the etched locations of the substrate are further filled with AlAs.

In a second aspect, the present invention provides a method for manufacturing a spot-improved vertical cavity surface emitting laser, including:

providing a substrate;

roughening the edge of the substrate to form a first area and a second area located around the first area, wherein the flatness degree of the second area is smaller than that of the first area;

sequentially forming an N-type DBR layer, a light-emitting layer and a P-type DBR layer on the front surface of the substrate;

performing an oxidation process on one side of the P-type DBR layer close to the light-emitting layer to form an annular oxide layer, wherein the annular inner diameter formed by the second region is smaller than the light-emitting aperture formed by the oxide layer;

forming a contact layer and a ring-shaped P-type electrode on the side of the P-type DBR layer far away from the light-emitting layer;

and forming an N electrode on the back surface of the substrate.

In an alternative embodiment, the step of roughening the substrate to form a first region and a second region around the first region includes:

coating positive photoresist on the front side of the substrate;

adding the photomask with the holes and carrying out exposure and development treatment to define a plurality of first openings on the edge of the substrate;

and etching the substrate at each first opening to form a first area and a second area around the first area on the substrate, wherein the second area comprises a plurality of grooves arranged at intervals.

In an alternative embodiment, the step of roughening the substrate to form a first region and a second region around the first region includes:

coating a negative photoresist on the front side of the substrate;

adding the photomask with the holes and carrying out exposure and development treatment to define a plurality of second openings on the edge of the substrate;

and etching the substrate at each second opening to form a first area and a second area around the first area on the substrate, wherein the second area comprises a plurality of columnar structures arranged at intervals.

The beneficial effects of the embodiment of the invention include, for example:

the embodiment of the application provides a facula-improved vertical cavity surface emitting laser, which comprises a substrate, wherein the substrate comprises a first area and a second area located around the first area, and the flatness degree of the second area is smaller than that of the first area. An N-type DBR layer, a light-emitting layer, and a P-type DBR layer are formed in this order on the front surface of the substrate, an annular oxide layer is formed in the P-type DBR layer, and the annular inner diameter of the second region is smaller than the light-emitting aperture of the oxide layer. In the laser, the second region with lower flatness is grown on the epitaxial layer, the formed shape structure is degraded, and the reflectivity of the formed N-type DBR and P-type DBR is correspondingly reduced. After the VCSEL device is manufactured, the reflectivity of the N-type DBR and the P-type DBR above the second region is reduced, and the reflected light is less. Because the aperture of the second area is smaller than the light-emitting aperture, the light-emitting amount is weakened in the area with larger current density (large light-emitting amount) near the light-emitting aperture, and the problem of non-uniform light-emitting is finally improved.

In addition, the embodiment of the application provides a manufacturing method of the facula-improved vertical cavity surface emitting laser, the manufacturing method can form a first area and a second area located around the first area by performing roughening treatment on the edge of the substrate, and the flatness degree of the second area is smaller than that of the first area. According to the method, the substrate is directly roughened to form the second region, the formed second region with lower flatness can be used for weakening the light reflection of the upper DBR layer and the lower DBR layer at the corresponding positions, the light emission of strong light near the light-emitting aperture can be weakened, and the purpose of improving the final light spot mode is achieved on the basis of not additionally arranging other hierarchical structures.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

Fig. 1 is a schematic structural diagram of a spot-improved vcsel provided in an embodiment of the present application;

FIG. 2 is a schematic structural diagram of a conventional VCSEL;

FIG. 3 is a partial schematic view of a second region provided in accordance with an embodiment of the present application;

fig. 4 is a flowchart of a method for manufacturing a spot-improved vcsel according to an embodiment of the present disclosure;

FIG. 5 is a flowchart of sub-steps included in step S120 of FIG. 4;

fig. 6 to fig. 8 are schematic structural diagrams of devices manufactured and formed in various steps of a manufacturing method according to an embodiment of the present disclosure;

fig. 9 is another flowchart of the sub-steps included in step S120 in fig. 4.

Icon: 10-a substrate; 11-a first region; 12-a second region; a 20-N type DBR layer; 30-a light-emitting layer; a 40-P type DBR layer; 41-an oxide layer; 50-a contact layer; a 60-P electrode; 70-electrode.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

In the description of the present invention, it should be noted that if the terms "upper", "lower", "inside", "outside", etc. indicate an orientation or a positional relationship based on that shown in the drawings or that the product of the present invention is used as it is, this is only for convenience of description and simplification of the description, and it does not indicate or imply that the device or the element referred to must have a specific orientation, be constructed in a specific orientation, and be operated, and thus should not be construed as limiting the present invention.

Furthermore, the appearances of the terms "first," "second," and the like, if any, are used solely to distinguish one from another and are not to be construed as indicating or implying relative importance.

It should be noted that the features of the embodiments of the present invention may be combined with each other without conflict.

Referring to fig. 1, a device structure diagram of a spot-improved vcsel according to an embodiment of the present disclosure is shown. The laser comprises a substrate 10, which substrate 10 may be a gallium arsenide substrate 10. The substrate 10 comprises a flat first area 11 and a second area 12 located around the first area 11, wherein the flatness of the second area 12 is less than that of the first area 11, and the second area 12 is obtained by roughening the front surface of the substrate 10. Wherein the flatness is inversely related to the roughness, the higher the roughness of the surface, the lower the flatness, and the second region 12 is obtained by performing the roughening treatment on the surface of the substrate 10, so that the roughness of the second region 12 is higher than the roughness of the surface of the substrate 10 (i.e. the surface of the first region 11), and conversely, the flatness of the second region 12 is smaller than the flatness of the surface of the substrate 10 (i.e. the surface of the first region 11).

In addition, the laser further includes an N-type DBR layer 20 disposed on the front surface of the substrate 10, a light-emitting layer 30 disposed on a side of the N-type DBR layer 20 away from the substrate 10, and a P-type DBR layer 40 disposed on a side of the light-emitting layer 30 away from the N-type DBR layer 20. An annular oxide layer 41 is formed on the P-type DBR layer 40 on the side close to the light emitting layer 30, and the annular inner diameter of the second region 12 is smaller than the light emitting aperture formed by the oxide layer 41.

In addition, the laser includes a contact layer 50 and a P-electrode 60 in a ring shape provided on the P-type DBR layer 40 on the side away from the light emitting layer 30, and an N-electrode 70 provided on the rear surface of the substrate 10.

When the second region 12 having a low flatness is not formed, the electric field intensity around the ring-shaped P-electrode 60 is strong, and the electric field intensity in the central region distant from the electrode is weak, which results in non-uniform carrier distribution in the mesa structure of the laser. The carrier concentration is higher in the edge area of the light outlet hole of the annular electrode, and the carrier concentration is lower in the central area, so that the light intensity is stronger near the annular electrode area, and the light intensity is weaker in the central area, and a donut effect with brighter periphery and darker middle is formed, as shown in fig. 2.

In this embodiment, the second region 12 having a low flatness is formed in the edge region of the substrate 10, and the annular inner diameter of the second region 12 is smaller than the light exit aperture of the oxide layer 41.

The second region 12 reduces the flatness of the substrate 10, the profile of the epitaxial layer formed thereon is degraded, and the reflectivity of the N-type DBR layer 20 and the P-type DBR layer 40 is reduced accordingly. After the VCSEL device is formed, the N-type DBR layer 20 and the P-type DBR layer 40 above the second region 12 have reduced reflectivity and emit less light. In addition, since the annular inner diameter of the second region 12 is smaller than the light exit aperture, the light exit amount is also weakened in a region with a large current density (region with a large light exit amount) near the light exit aperture, so that the light exit amount in the edge region of the light exit aperture is close to the light exit amount in the middle region of the light exit aperture, and the problem of uneven light exit is solved.

In this embodiment, the second region 12 is obtained by performing a corresponding process on the substrate 10, and the purpose of the process is to make the flatness of the second region 12 smaller than that of the original substrate 10 (i.e., the flatness of the first region 11). Alternatively, the second region 12 may be formed in an etched region by etching an edge region of the substrate 10. The second region 12 formed by etching the edge region of the substrate 10 may include a plurality of roughness elements for reducing the flatness of the edge region, and the roughness elements may be spaced apart from each other as shown in fig. 3.

As a possible implementation, the so-called roughness feature may be a groove formed on the substrate 10.

As another possible embodiment, the roughness elements may also be columnar structures formed on the substrate 10.

In the present embodiment, the cross-section of the roughness elements may be circular, elliptical, square, polygonal, etc., and is exemplarily shown as circular in fig. 3. That is, the circular structure shown in fig. 3 may be a circular columnar structure, or a circular groove.

When the roughness elements are a plurality of spaced apart grooves on the substrate 10, the cross-sectional shape of the grooves may be circular, elliptical, square, polygonal, or the like. That is, the second region 12 is a ring-shaped structure formed on the substrate 10 as a whole, and includes a plurality of grooves spaced apart from each other in the ring-shaped region. Thus, since the second region 12 includes a plurality of grooves, the flatness of the substrate 10 is lower than that of the original substrate.

The light emission of the upper and lower DBR layers (i.e., the positions close to the edges of the light emitting holes) at the corresponding positions in the vertical direction can be weakened by using the second region 12 provided with a plurality of grooves, so that the light emitting amount is reduced, and the purpose of uniform light emitting is achieved.

In this embodiment, a positive photoresist may be coated on the substrate 10, and after exposure and development are performed by using the mask with openings, the positive photoresist at the positions corresponding to the openings is dissolved, so as to expose the etching regions corresponding to the positions of the openings. The substrate 10 may be etched based on the etching region to form a plurality of spaced-apart grooves at the edge of the substrate 10.

In this embodiment, the cross-sectional width of the roughness elements may be less than or equal to 2.5 microns, e.g. the cross-sectional width of the grooves formed may be less than or equal to 2.5 microns, e.g. 1 micron. The distance between the roughness elements may be less than or equal to 2.5 micrometers, e.g. the distance between every two grooves may be less than or equal to 2.5 micrometers, e.g. may be 1 micrometer.

Since the second region 12 is obtained by etching the edge of the substrate 10, the thickness of the second region 12 should be smaller than the thickness of the substrate 10. In this embodiment, the etching depth of the rough features is less than the thickness of the substrate 10, that is, the depth of the grooves formed by etching is less than the thickness of the substrate 10.

In one possible embodiment, when the roughness elements are pillar structures on the substrate 10, that is, the other regions of the second region 12 except for the respective pillar structures are etched regions of the substrate 10. Similarly, the edge region of the substrate 10 is etched to form the second region 12 having a plurality of pillar-shaped structures disposed at intervals, and the flatness is reduced compared with the original substrate 10, so that the light reflection of the partial regions (i.e., the regions near the edge of the light-emitting hole) of the upper and lower DBR layers at the corresponding positions in the vertical direction is weakened, and the amount of light emitted is reduced, thereby achieving the purpose of uniform light emission.

In this embodiment, the cross-sectional shape of the formed columnar structure may be circular, elliptical, square, or polygonal, etc., without limitation. And the width of the cross section of each columnar structure may be less than or equal to 2.5 microns, and may be, for example, 1 micron. The distance between each two columnar structures may be less than or equal to 2.5 microns, and may be 1 micron, for example. While the depth of the columnar structure is less than the thickness of the substrate 10.

In this embodiment, a negative photoresist may be coated on the substrate 10, and after exposure and development are performed by using the mask with openings, the negative photoresist in the regions not covered by the mask is dissolved, and the negative photoresist corresponding to the positions of the openings is retained. The substrate 10 is etched at various locations based on the dissolved negative photoresist to form a plurality of spaced-apart columnar structures in the edge region of the substrate 10.

In addition, considering that the laser adopts a current confinement structure, the current confinement structure increases the current density, which causes the accumulation of heat energy of the device. In order to avoid the reliability inversion of the device due to the accumulation of thermal energy, in the present embodiment, the substrate 10 is further filled with aluminum arsenide AlAs at the etched position.

The thermal conductivity of aluminum arsenide is 0.9W/cm.k, and the thermal conductivity of gallium arsenide substrate 10 is 0.55W/cm.k, so that the heat dissipation performance of the device can be improved by filling aluminum arsenide at the etched position of substrate 10, and the problem of reliability inversion caused by heat energy accumulation of the device is avoided.

Because the annular inner diameter formed by the second region 12 is smaller than the light-emitting aperture formed by the oxide layer 41, the aluminum arsenide filled in the second region 12 can effectively dissipate the heat of the edge region of the light-emitting aperture with the most serious heat generation, and effectively improve the heat dissipation performance of the device.

Referring to fig. 4, the present disclosure further provides a method for manufacturing a flare-improved vertical cavity surface emitting laser, which can be used for manufacturing the flare-improved vertical cavity surface emitting laser, and the detailed process of the manufacturing method will be described below.

In step S110, a substrate 10 is provided. The substrate 10 may be a gallium arsenide substrate 10.

Step S120, performing a roughening process on the substrate 10 to form a first region 11 and a second region 12 located around the first region 11, where a flatness degree of the second region 12 is smaller than that of the first region 11.

As a possible embodiment, the second region 12 formed by roughening the substrate 10 may include a plurality of grooves at intervals. Referring to fig. 5 in combination with fig. 6 to 8, the first region 11 and the second region 12 may be formed on the basis of the substrate 10 in the following manner.

Step S121A, coating a positive photoresist on the front surface of the substrate 10.

In step S122A, the opened mask is added and exposed to a developing process to define a plurality of first openings on the edge of the substrate 10.

Step S123A, etching the substrate 10 at each of the first openings to form a first region 11 and a second region 12 located around the first region on the substrate 10, where the second region 12 includes a plurality of grooves arranged at intervals.

Referring to fig. 6, in the present embodiment, a photoresist, such as a positive photoresist, is coated on the front surface of the substrate 10. After exposure and development processing using the mask after the opening, the structure as shown in fig. 7 is obtained. The positions of the positive photoresist corresponding to the openings on the mask are dissolved to expose a portion of the substrate 10, and the exposed positions of the substrate 10 are defined as first openings.

The substrate 10 may be etched based on the first opening defined in the substrate 10, and after the etching is completed, the remaining positive photoresist on the device is stripped and cleaned, so that the structure shown in fig. 8 can be obtained.

The etched edge region of the front surface of the substrate 10 is the second region 12, and the non-etched middle region of the substrate 10 is the first region 11. Since the second region 12 is etched on the basis of the substrate 10, and includes a plurality of spaced apart recesses therein, the second region 12 is less planar than the first region 11.

As another possible implementation, the second region 12 formed by etching the substrate 10 may include a plurality of pillar structures disposed at intervals. Referring to fig. 9, in this embodiment, the second region 12 may be formed by the following steps.

In step S121B, a negative photoresist is coated on the front surface of the substrate 10.

In step S122B, the opened mask is added and exposed to a developing process to define a plurality of second openings at the edge of the substrate 10.

Step S123B, etching the substrate 10 at each second opening to form a first region 11 and a second region 12 located around the first region on the substrate 10, where the second region 12 includes a plurality of pillar structures arranged at intervals.

In this embodiment, since the substrate 10 is coated with the negative photoresist, after the mask after opening the hole is used and exposed and developed, the region of the negative photoresist corresponding to the opening position is retained, and the other region covered by the mask is dissolved. Thus, the negative photoresist left on the substrate 10 after exposure and development is in the form of spaced columns conforming to the shape of the openings, and the regions between the columns are the regions where the substrate 10 is exposed, i.e., the defined plurality of second openings.

And etching the substrate 10 based on each second opening, and then stripping the negative photoresist and cleaning the device, so that a plurality of columnar structures arranged at intervals are left on the substrate 10. That is, the edge region of the substrate 10 is a circle of the second region 12 including a plurality of pillar structures arranged at intervals, and the region surrounded by the second region 12 is the first region 11.

Similarly, since the second region 12 is etched based on the substrate 10, the flatness of the second region 12 is less than that of the first region 11.

On this basis, referring to fig. 4, additional levels of devices are formed by the following epitaxial growth steps.

In step S130, an N-type DBR layer 20, a light emitting layer 30, and a P-type DBR layer 40 are sequentially formed on the front surface of the substrate 10.

The N-type DBR layer 20 has a multilayer laminated structure, and may include, for example, a plurality of aluminum arsenide layers and gallium arsenide layers alternately arranged, the aluminum arsenide layers and the gallium arsenide layers have different refractive indexes, and the number of the aluminum arsenide layers and the number of the gallium arsenide layers are respectively a plurality of layers. So that the N-type DBR layer 20 has high reflectivity.

The light-emitting layer 30 is a layer that generates light energy, and the light-emitting layer 30 may include indium arsenide or aluminum gallium arsenide.

The P-type DBR layer 40 has a multilayer laminated structure, and may include, for example, a plurality of aluminum arsenide layers and gallium arsenide layers alternately arranged, the refractive indices of the aluminum arsenide layers and the gallium arsenide layers are different, and the number of the aluminum arsenide layers and the number of the gallium arsenide layers are respectively a plurality of layers. So that the P-type DBR layer 40 has high reflectivity.

In step S140, an oxidation process is performed on a side of the P-type DBR layer 40 close to the light emitting layer to form an annular oxide layer 41, and an annular inner diameter formed by the second region 12 is smaller than an optical exit aperture formed by the oxide layer 41.

Wherein the oxide layer 41 may be made of Al₂O₃The annular inner diameter D of the second region 12 is smaller than the light exit aperture D of the oxide layer 41.

In step S150, a contact layer 50 and a ring-shaped P-type electrode are formed on the P-type DBR layer 40 on the side away from the light-emitting layer 30.

In step S160, an N electrode 70 is formed on the back surface of the substrate 10.

In this embodiment, the second region 12 with a low flatness is formed by etching the edge of the substrate 10, which causes an outer delay to grow thereon, the formed profile is degraded, and the reflectivity of the formed N-type DBR layer 20 and the P-type DBR layer 40 is correspondingly reduced. After the VCSEL device is fabricated, the N-type DBR layer 20 and the P-type DBR layer 40 above the second region 12 have reduced reflectivity and reflect less light. In addition, since the inner diameter of the ring formed by the second region 12 is smaller than the light exit aperture, the light exit amount is also weakened in the region with larger current density near the light exit aperture, that is, the region with larger light exit amount, so as to improve the problem of uneven light exit.

The spot-improved vertical cavity surface emitting laser provided in this embodiment is manufactured by the above manufacturing method, and therefore, for other relevant information of the manufacturing method of the laser, reference may be made to the relevant description in the laser, and details of this embodiment are not repeated herein.

In summary, the embodiment of the present application provides a spot-improved vcsel, which includes a substrate 10, where the substrate 10 includes a first region 11 and a second region 12 located around the first region 11, and a flatness of the second region 12 is smaller than that of the first region 11. Further, an N-type DBR layer 20, a light emitting layer 30, and a P-type DBR layer 40 are sequentially formed on the front surface of the substrate 10, an annular oxide layer 41 is formed in the P-type DBR layer 40, and the annular inner diameter of the second region 12 is smaller than the light emitting aperture formed by the oxide layer 41. In this laser, the second region 12 having a low flatness on which epitaxy is grown has a deteriorated profile structure, and the reflectivities of the N-type DBR layer 20 and the P-type DBR layer 40 formed therefrom are also decreased. After the VCSEL device is manufactured, the reflectivities of the N-type DBR layer 20 and the P-type DBR layer 40 above the second region 12 are reduced, and the reflected light is small; since the aperture of the second region 12 is smaller than the light-emitting aperture, the light-emitting amount is also weakened in the region with larger current density (large light-emitting amount) near the light-emitting aperture, so as to improve the problem of non-uniform light-emitting.

In addition, according to the manufacturing method of the spot-improved vertical cavity surface emitting laser provided by the embodiment of the application, the edge of the substrate 10 may be roughened to form the first region 11 and the second region 12 located around the first region 11, and the flatness of the second region 12 is smaller than that of the first region 11. According to the method, the substrate 10 is directly roughened to form the second region 12, the formed second region 12 with low flatness can be used for weakening the light reflection of the upper DBR layer and the lower DBR layer at the corresponding positions, the light emission of strong light at the edge of the light-emitting aperture can be weakened, and the purpose of improving the uneven light-emitting performance and the final light spot mode is achieved on the basis of not additionally arranging other hierarchical structures.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.