阅读说明：本技术 一种垂直腔面发射激光器及其制备方法 (Vertical cavity surface emitting laser and preparation method thereof ) 是由 翁玮呈 梁栋 刘嵩 丁维遵 彭俊彦 于 2021-09-07 设计创作，主要内容包括：本发明实施例公开了一种垂直腔面发射激光器及其制备方法,制备方法中通过在同一刻蚀工艺中刻蚀位于N型欧姆层远离衬底一侧的第一钝化层,以及位于发光台面结构中P型接触层远离衬底一侧的第一钝化层,以在N型欧姆层远离衬底一侧形成第一开口暴露N型欧姆层,在发光台面结构中P型接触层远离衬底一侧形成第二开口暴露P型接触层,减少了开口刻蚀工艺的次数,并且在同一金属沉积工艺中,于第一开口中形成第一电极层以及于第二开口中依次形成P型欧姆层和第二电极层,减少了金属沉积工艺的次数以及金属耗材的量,从而提高了激光器的制备效率,缩短了激光器的制备时长,降低了制备成本。(The embodiment of the invention discloses a vertical cavity surface emitting laser and a preparation method thereof, wherein in the preparation method, a first passivation layer positioned at one side of an N-type ohmic layer far away from a substrate and a first passivation layer positioned at one side of a P-type contact layer far away from the substrate in a light-emitting mesa structure are etched in the same etching process to form a first opening exposing the N-type ohmic layer at one side of the N-type ohmic layer far away from the substrate, and a second opening exposing the P-type contact layer at one side of the P-type contact layer far away from the substrate in the light-emitting mesa structure, so that the times of an opening etching process are reduced, and in the same metal deposition process, a first electrode layer is formed in the first opening and a P-type ohmic layer and a second electrode layer are sequentially formed in the second opening, so that the times of the metal deposition process and the amount of metal consumables are reduced, thereby improving the preparation efficiency of the laser and shortening the preparation time of the laser, the preparation cost is reduced.)

1. A method for manufacturing a vertical cavity surface emitting laser includes:

providing a substrate, and forming a semiconductor epitaxial structure on one side of the substrate; the semiconductor epitaxial structure comprises an N-type contact layer, an N-type distributed Bragg reflection layer, a quantum well layer, a P-type distributed Bragg reflection layer and a P-type contact layer which are sequentially formed on a substrate;

etching a groove on the semiconductor epitaxial structure to form a light-emitting mesa structure; wherein the trench exposes a portion of the N-type contact layer;

forming a current confinement layer in the light emitting mesa structure; the current limiting layer is provided with an opening, and the opening is used for defining a light emitting area of the light emitting mesa structure;

forming an N-type ohmic layer on one side, far away from the substrate, of the N-type contact layer exposed by the groove; the distance between the N-type ohmic layer and the side wall of the groove is larger than zero;

forming a first passivation layer on one side of the semiconductor epitaxial structure far away from the substrate and on the side wall and the bottom of the groove; etching a first passivation layer positioned on one side of the N-type ohmic layer, which is far away from the substrate, and a first passivation layer positioned on one side of the P-type contact layer, which is far away from the substrate, in the light-emitting mesa structure in the same etching process so as to form a first opening on one side of the N-type ohmic layer, which is far away from the substrate, to expose the N-type ohmic layer, and form a second opening on one side of the P-type contact layer, which is far away from the substrate, in the light-emitting mesa structure to expose the P-type contact layer;

and in the same metal deposition process, forming a first electrode layer in the first opening and sequentially forming a P-type ohmic layer and a second electrode layer in the second opening.

2. The method of claim 1, further comprising a second passivation layer between the first passivation layer on a side of the semiconductor epitaxial structure remote from the substrate and the semiconductor epitaxial structure; before the etching the semiconductor epitaxial structure to form the trench, the method further includes:

and forming a second passivation layer on one side of the semiconductor epitaxial structure far away from the substrate, and etching the second passivation layer in the region where the groove is located to expose the semiconductor epitaxial structure to be etched.

3. The method according to claim 1, wherein the N-type dbr and the P-type dbr are formed by laminating two different refractive index layers, i.e., an algaas material layer and a gaas material layer, or by laminating two different refractive index layers, i.e., an algaas material layer with a high al composition and an algaas material layer with a low al composition.

4. The method of claim 3, wherein the forming a current confinement layer in the light-emitting mesa structure comprises:

and oxidizing the aluminum gallium arsenic with the highest aluminum component in the P-type distributed Bragg reflection layer exposed by the groove by a wet method to form the current limiting layer.

5. The method for manufacturing a vertical cavity surface emitting laser according to claim 1, wherein the number of said light emitting mesa structures is 1; the forming of the N-type ohmic layer on the side, far away from the substrate, of the N-type contact layer exposed by the groove comprises the following steps:

and forming an N-type ohmic layer on one side of the N-type contact layer, which is far away from the substrate, along the extending direction of the groove surrounding the light-emitting mesa structure.

6. The method for manufacturing a vertical cavity surface emitting laser according to claim 1, wherein the number of said light emitting mesa structures is plural; the forming of the N-type ohmic layer on the side, far away from the substrate, of the N-type contact layer exposed by the groove comprises the following steps:

and forming a common N-type contact layer in the grooves on the same side of the light-emitting mesa structures.

7. A vertical cavity surface emitting laser, comprising:

the semiconductor epitaxial structure comprises a substrate and a semiconductor epitaxial structure positioned on one side of the substrate;

the semiconductor epitaxial structure comprises an N-type contact layer, an N-type distributed Bragg reflection layer, a quantum well layer, a P-type distributed Bragg reflection layer and a P-type contact layer which are sequentially stacked on a substrate; the semiconductor epitaxial structure comprises a groove and a light-emitting mesa structure surrounded by the groove; the N-type ohmic layer of the exposed part of the groove; the light-emitting mesa structure comprises a current limiting layer; the current limiting layer is provided with an opening, and the opening is used for defining a light emitting area of the light emitting mesa structure;

the N-type ohmic layer is positioned at the bottom of the groove; the distance between the N-type ohmic layer and the side wall of the groove is larger than zero;

the first passivation layer is positioned on one side of the semiconductor epitaxial structure far away from the substrate and on the side wall and the bottom of the groove; the first passivation layer includes a first opening and a second opening; the first opening exposes the N-type ohmic layer, and the second opening exposes the P-type contact layer in the light-emitting mesa structure; wherein the first opening and the second opening are formed in the same etching process;

the first electrode layer is in contact with the N-type ohmic layer exposed by the first opening; the P-type ohmic layer is in contact with the P-type contact layer exposed by the second opening; the second electrode layer is positioned on one side of the P-type ohmic layer far away from the P-type contact layer; the N-type electrode layer, the P-type ohmic layer and the P-type electrode layer are formed in the same metal deposition process.

8. A vertical cavity surface emitting laser according to claim 7, further comprising:

and the second passivation layer is positioned between the semiconductor epitaxial structure and the first passivation layer and covers the surface of one side, far away from the substrate, of the semiconductor epitaxial structure.

9. A vertical cavity surface emitting laser according to claim 7,

the N-type distributed Bragg reflection layer and the P-type distributed Bragg reflection layer are formed by laminating two material layers with different refractive indexes, namely an aluminum gallium arsenic material layer and a gallium arsenide material layer, or by laminating two material layers with different refractive indexes, namely an aluminum gallium arsenic material layer with a high aluminum component and an aluminum gallium arsenic material layer with a low aluminum component.

10. A vertical cavity surface emitting laser according to claim 9, wherein said number of said light emitting mesa structures includes a plurality, and said N-type ohmic layer is a common N-type ohmic layer located in a trench on a same side of a plurality of said light emitting mesa structures.

Technical Field

The embodiment of the invention relates to the technical field of lasers, in particular to a vertical cavity surface emitting laser and a preparation method thereof.

Background

Vertical Cavity Surface Emitting Lasers (VCSELs) are developed on the basis of gallium arsenide semiconductor materials, have the advantages of small size, circular output light spots, single longitudinal mode output, small threshold current, low price, easiness in integration into large-area arrays and the like, and are widely applied to the fields of optical communication, optical interconnection, high-power application of optical storage, industrial cutting, distance measurement, Lidar, medical treatment and the like.

Currently, vertical cavity surface emitting lasers are receiving attention due to their excellent performance and wide application. High production efficiency is required to achieve low manufacturing costs, and thus the method for manufacturing is strictly controllable. However, the existing preparation method of the vertical cavity surface emitting laser has the problems of long average total process time, more metal consumables and high preparation cost.

Disclosure of Invention

The embodiment of the invention provides a vertical cavity surface emitting laser and a preparation method thereof, which aim to improve the preparation efficiency of the laser and reduce the preparation cost.

In a first aspect, an embodiment of the present invention provides a method for manufacturing a vertical cavity surface emitting laser, including:

providing a substrate, and forming a semiconductor epitaxial structure on one side of the substrate; the semiconductor epitaxial structure comprises an N-type contact layer, an N-type distributed Bragg reflection layer, a quantum well layer, a P-type distributed Bragg reflection layer and a P-type contact layer which are sequentially formed on a substrate;

etching a groove on the semiconductor epitaxial structure to form a light-emitting mesa structure; wherein the trench exposes a portion of the N-type contact layer;

forming a current confinement layer in the light emitting mesa structure; the current limiting layer is provided with an opening, and the opening is used for defining a light emitting area of the light emitting mesa structure;

forming an N-type ohmic layer on one side, far away from the substrate, of the N-type contact layer exposed by the groove; the distance between the N-type ohmic layer and the side wall of the groove is larger than zero;

forming a first passivation layer on one side of the semiconductor epitaxial structure far away from the substrate and on the side wall and the bottom of the groove; etching a first passivation layer positioned on one side of the N-type ohmic layer, which is far away from the substrate, and a first passivation layer positioned on one side of the P-type contact layer, which is far away from the substrate, in the light-emitting mesa structure in the same etching process so as to form a first opening on one side of the N-type ohmic layer, which is far away from the substrate, to expose the N-type ohmic layer, and form a second opening on one side of the P-type contact layer, which is far away from the substrate, in the light-emitting mesa structure to expose the P-type contact layer;

and in the same metal deposition process, forming a first electrode layer in the first opening and sequentially forming a P-type ohmic layer and a second electrode layer in the second opening.

Optionally, a second passivation layer is further included between the first passivation layer on the side of the semiconductor epitaxial structure away from the substrate and the semiconductor epitaxial structure; before the etching the semiconductor epitaxial structure to form the trench, the method further includes:

and forming a second passivation layer on one side of the semiconductor epitaxial structure far away from the substrate, and etching the second passivation layer in the region where the groove is located to expose the semiconductor epitaxial structure to be etched.

Optionally, the N-type distributed bragg reflector and the P-type distributed bragg reflector are formed by laminating two material layers with different refractive indexes, namely an aluminum gallium arsenic material layer and a gallium arsenide material layer, or by laminating two material layers with different refractive indexes, namely an aluminum gallium arsenic material layer with a high aluminum component and an aluminum gallium arsenic material layer with a low aluminum component.

Optionally, the forming a current confinement layer in the light-emitting mesa structure includes:

and oxidizing the aluminum gallium arsenic with the highest aluminum component in the P-type distributed Bragg reflection layer exposed by the groove by a wet method to form the current limiting layer.

Optionally, the number of the light-emitting mesa structures is 1; the forming of the N-type ohmic layer on the side, far away from the substrate, of the N-type contact layer exposed by the groove comprises the following steps:

and forming an N-type ohmic layer on one side of the N-type contact layer, which is far away from the substrate, along the extending direction of the groove surrounding the light-emitting mesa structure.

Optionally, the number of the light-emitting mesa structures is multiple; the forming of the N-type ohmic layer on the side, far away from the substrate, of the N-type contact layer exposed by the groove comprises the following steps:

and forming a common N-type contact layer in the grooves on the same side of the light-emitting mesa structures.

In a second aspect, an embodiment of the present invention provides a vertical cavity surface emitting laser, including:

the semiconductor epitaxial structure comprises a substrate and a semiconductor epitaxial structure positioned on one side of the substrate;

the semiconductor epitaxial structure comprises an N-type contact layer, an N-type distributed Bragg reflection layer, a quantum well layer, a P-type distributed Bragg reflection layer and a P-type contact layer which are sequentially stacked on a substrate; the semiconductor epitaxial structure comprises a groove and a light-emitting mesa structure surrounded by the groove; the N-type ohmic layer of the exposed part of the groove; the light-emitting mesa structure comprises a current limiting layer; the current limiting layer is provided with an opening, and the opening is used for defining a light emitting area of the light emitting mesa structure;

the N-type ohmic layer is positioned at the bottom of the groove; the distance between the N-type ohmic layer and the side wall of the groove is larger than zero;

the first passivation layer is positioned on one side of the semiconductor epitaxial structure far away from the substrate and on the side wall and the bottom of the groove; the first passivation layer includes a first opening and a second opening; the first opening exposes the N-type ohmic layer, and the second opening exposes the P-type contact layer in the light-emitting mesa structure; wherein the first opening and the second opening are formed in the same etching process;

the first electrode layer is in contact with the N-type ohmic layer exposed by the first opening; the P-type ohmic layer is in contact with the P-type contact layer exposed by the second opening; the second electrode layer is positioned on one side of the P-type ohmic layer far away from the P-type contact layer; the N-type electrode layer, the P-type ohmic layer and the P-type electrode layer are formed in the same metal deposition process.

Optionally, the vertical cavity surface emitting laser further includes:

and the second passivation layer is positioned between the semiconductor epitaxial structure and the first passivation layer and covers the surface of one side, far away from the substrate, of the semiconductor epitaxial structure.

Optionally, the N-type distributed bragg reflector and the P-type distributed bragg reflector are formed by laminating two material layers with different refractive indexes, namely an aluminum gallium arsenic material layer and a gallium arsenide material layer, or by laminating two material layers with different refractive indexes, namely an aluminum gallium arsenic material layer with a high aluminum component and an aluminum gallium arsenic material layer with a low aluminum component.

Optionally, the number of the light-emitting mesa structures includes a plurality of light-emitting mesa structures, and the N-type ohmic layer is a common N-type ohmic layer and is located in a plurality of grooves on the same side of the light-emitting mesa structures.

The embodiment of the invention provides a vertical cavity surface emitting laser and a preparation method thereof, wherein the preparation method comprises the following steps: providing a substrate, and forming a semiconductor epitaxial structure on one side of the substrate; the semiconductor epitaxial structure comprises an N-type contact layer, an N-type distributed Bragg reflection layer, a quantum well layer, a P-type distributed Bragg reflection layer and a P-type contact layer which are sequentially formed on a substrate; etching a groove on the semiconductor epitaxial structure to form a light-emitting mesa structure; wherein the trench exposes a portion of the N-type ohmic layer; forming a current confinement layer in the light-emitting mesa structure; the current limiting layer is provided with an opening which is used for defining a light emitting area of the light emitting mesa structure; forming an N-type ohmic layer on one side of the N-type contact layer exposed by the groove and far away from the substrate; the distance between the N-type ohmic layer and the side wall of the groove is larger than zero; forming a first passivation layer on one side of the semiconductor epitaxial structure far away from the substrate and on the side wall and the bottom of the groove; etching a first passivation layer positioned on one side of the N-type ohmic layer, which is far away from the substrate, and a first passivation layer positioned on one side of the P-type contact layer, which is far away from the substrate, in the light-emitting table structure in the same etching process so as to form a first opening on one side of the N-type ohmic layer, which is far away from the substrate, to expose the N-type ohmic layer, and form a second opening on one side of the P-type contact layer, which is far away from the substrate, in the light-emitting table structure to expose the P-type contact layer; in the same metal deposition process, forming a first electrode layer in the first opening and sequentially forming a P-type ohmic layer and a second electrode layer in the second opening; according to the technical scheme provided by the embodiment of the invention, the first passivation layer positioned on one side of the N-type ohmic layer, which is far away from the substrate, and the first passivation layer positioned on one side of the P-type contact layer, which is far away from the substrate, in the light-emitting mesa structure are etched in the same etching process, so that the first opening exposing the N-type ohmic layer is formed on one side of the N-type ohmic layer, which is far away from the substrate, and the second opening exposing the P-type contact layer is formed on one side of the P-type contact layer, which is far away from the substrate, in the light-emitting mesa structure, so that the times of the opening etching process are reduced, and in the same metal deposition process, the first electrode layer is formed in the first opening and the P-type ohmic layer and the second electrode layer are sequentially formed in the second opening, so that the times of the metal deposition process and the amount of metal consumables are reduced, thereby improving the preparation efficiency of the laser, shortening the preparation time of the laser and reducing the preparation cost.

Drawings

FIG. 1 is a flow chart of a method for fabricating a VCSEL provided by an embodiment of the present invention;

fig. 2 is a cross-sectional view of the structure in step S110 of the method for manufacturing a vertical cavity surface emitting laser according to the embodiment of the invention;

fig. 3 is a cross-sectional view of the structure in step S120 of the method for manufacturing a vertical cavity surface emitting laser according to the embodiment of the invention;

fig. 4 is a cross-sectional view of the structure in step S130 of a method for manufacturing a vertical cavity surface emitting laser according to an embodiment of the invention;

fig. 5 is a cross-sectional view of the structure in step S140 of the method for manufacturing a vertical cavity surface emitting laser according to the embodiment of the invention;

FIGS. 6-7 are cross-sectional views of the structure of step S150 in a method for fabricating a VCSEL according to an embodiment of the invention;

fig. 8 is a cross-sectional view of the structure in step S160 of a method for manufacturing a vertical cavity surface emitting laser according to an embodiment of the present invention;

FIG. 9 is a cross-sectional view of a second passivation layer formed in a method of fabricating a VCSEL according to an embodiment of the present invention;

FIG. 10 is a cross-sectional view of a structure etched with a second passivation layer in a method for fabricating a VCSEL according to an embodiment of the invention;

FIG. 11 is a top view of a VCSEL provided by an embodiment of the present invention;

FIG. 12 is a top view of another VCSEL provided by an embodiment of the invention;

FIG. 13 is a cross-sectional view of a structure taken along line C3-C4 of FIG. 12;

FIG. 14 is a cross-sectional view of the alternative structure of FIG. 12 taken along line C3-C4.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.

As background art, the vertical cavity surface emitting Laser is developed based on gallium arsenide semiconductor material, and is different from other light sources such as LED (light emitting Diode) and LD (Laser Diode), and has the advantages of small volume, circular output light spot, single longitudinal mode output, small threshold current, low price, easy integration into large area array, and the like, and is widely applied to the fields of optical communication, optical interconnection, optical storage high power application, industrial cutting, ranging, Lidar, medical treatment, and the like. Vertical cavity surface emitting lasers are of interest for their excellent performance and wide application. High production efficiency is required to achieve low manufacturing costs, and thus the method for manufacturing is strictly controllable. At present, in the process of preparing the vertical cavity surface emitting laser, a P-type ohmic layer and an N-type ohmic layer are sequentially formed on two opposite sides of a substrate or on the same side of the substrate through two metal deposition processes, the process time is long, and a plurality of photomasks and more metal consumables are needed. In addition, in the prior art, under the condition that the P-type ohmic layer and the N-type ohmic layer are located on the same side of the substrate, after the passivation layer is formed on the side, away from the substrate, of the P-type ohmic layer and the N-type ohmic layer, the openings are respectively formed in the P-type ohmic layer and the N-type ohmic layer through different etching processes, so that the bonding pads are prepared on the P-type ohmic layer and the N-type ohmic layer, and the problems of long process time and complex preparation method are also solved. Statistics shows that the main process type is larger than 11 procedures, the number of photomasks is larger than 7, the plating times is larger than 5, and the average total process working hour is larger than 3 weeks, which are the basic conditions of the mainstream process and also the technical problem that the time and the cost are urgently needed to be further reduced in the field.

In view of this, an embodiment of the present invention provides a method for manufacturing a vertical cavity surface emitting laser, and fig. 1 is a flowchart of a method for manufacturing a vertical cavity surface emitting laser provided in an embodiment of the present invention, and with reference to fig. 1, the method includes:

s110, providing a substrate, and forming a semiconductor epitaxial structure on one side of the substrate; the semiconductor epitaxial structure comprises an N-type contact layer, an N-type distributed Bragg reflection layer, a quantum well layer, a P-type distributed Bragg reflection layer and a P-type contact layer which are sequentially formed on a substrate.

Specifically, fig. 2 is a cross-sectional view of the structure of step S110 in the method for manufacturing a vertical cavity surface emitting laser according to an embodiment of the present invention, and referring to fig. 2, a substrate 10 is provided, where the substrate 10 may be any material suitable for forming a vertical cavity surface emitting laser, such as gallium arsenide (GaAs). The substrate 10 may be an N-type doped semiconductor substrate or a P-type doped semiconductor substrate, and in this embodiment, the substrate 10 is an N-type doped semiconductor substrate. It should be noted that, since the N-type ohmic layer and the P-type ohmic layer are formed on the same side of the substrate 10 in the subsequent manufacturing process, the substrate 10 does not need to function as a conductor to conduct the N-type ohmic layer and the P-type ohmic layer, as compared to the case where the N-type ohmic layer and the P-type ohmic layer are formed on the opposite sides of the substrate 10. That is, the conductivity of the N-type doped semiconductor substrate is weak or non-conductive in this embodiment. In some embodiments, the substrate 10 may be a sapphire substrate or other material substrate, or at least the top surface of the substrate 10 may be comprised of one of silicon, gallium arsenide, silicon carbide, aluminum nitride, gallium nitride.

A semiconductor epitaxial structure 20 is formed on one side of the substrate 10, and the semiconductor epitaxial structure 20 includes an N-type contact layer 21, an N-type distributed bragg reflector layer 22, a quantum well layer 23, a P-type distributed bragg reflector layer 24, and a P-type contact layer 25 which are sequentially formed on the substrate 10. The N-type contact layer 21, the N-type distributed bragg reflector layer 22, the quantum well layer 23, the P-type distributed bragg reflector layer 24, and the P-type contact layer 25 may be formed by means of chemical vapor deposition. The N-type contact layer 21 is a current diffusion layer, and the material of the N-type contact layer 21 can be a highly doped gallium arsenide material, which has good conductivity. Also, the P-type contact layer 25 is a current diffusion layer, and the material of the P-type contact layer 25 may be a highly doped gallium arsenide material to make it conductive. The N-type distributed Bragg reflection layer 22 is formed by laminating two material layers with different refractive indexes, namely an aluminum gallium arsenic material layer and a gallium arsenide material layer, or by laminating two material layers with different refractive indexes, namely an aluminum gallium arsenic material layer with a high aluminum component and an aluminum gallium arsenic material layer with a low aluminum component; the quantum well layer 23 is an active layer, includes a quantum well composite structure formed by stacking and arranging GaAs and AlGaAs or InGaAs and AlGaAs materials, and converts electrical energy into optical energy. The P-type distributed bragg reflector layer 24 is formed by laminating two material layers of different refractive indexes, namely an aluminum gallium arsenic material layer and a gallium arsenide material layer, or by laminating two material layers of different refractive indexes, namely an aluminum gallium arsenic material layer with a high aluminum component and an aluminum gallium arsenic material layer with a low aluminum component. The N-type dbr 22 and the P-type dbr 24 are used to enhance the reflection of light generated from the active layer located in the middle, and then emit the light from the surface of the P-type dbr 24 to form laser light.

In some embodiments, the N-type and P-type DBR layers 22 and 24 include a series of alternating layers of different refractive index materials, wherein the effective optical thickness of each of the alternating layers (the layer thickness times the layer refractive index) is an odd integer multiple of the operating wavelength of the VCSEL, i.e., the effective optical thickness of each of the alternating layers is an odd integer multiple of the operating wavelength of the VCSEL. In some embodiments, the N-type dbr 22 and the P-type dbr 24 may be formed from other materials.

S120, etching a groove on the semiconductor epitaxial structure to form a light-emitting mesa structure; wherein the trench exposes a portion of the N-type contact layer.

Specifically, fig. 3 is a cross-sectional view of the structure in step S120 of the method for manufacturing a vertical cavity surface emitting laser according to the embodiment of the present invention, and referring to fig. 3, a trench is etched on the semiconductor epitaxial structure 20 by using a wet/dry etching method to form a light emitting mesa structure. The P-type contact layer 25 is etched downwards through an etching process, and at least a part of the N-type ohmic layer 40 is exposed in the formed groove, so that in order to form a preparation position in the subsequent process of preparing the N-type ohmic layer 40, the N-type ohmic layer 40 needs to be in contact with the N-type contact layer 21, ohmic contact between the N-type ohmic layer 40 and the N-type contact layer 21 is realized, current can flow from the N-type contact layer 21 to the N-type ohmic layer 40, and electric energy is provided for the light-emitting mesa structure.

S130, forming a current limiting layer in the light-emitting mesa structure; the current confinement layer is provided with an opening which is used for defining a light emitting area of the light emitting mesa structure.

Specifically, fig. 4 is a cross-sectional view of the structure in step S130 of the method for manufacturing a vertical cavity surface emitting laser according to the embodiment of the present invention, and referring to fig. 4, in this embodiment, the sidewall of the trench is oxidized by wet oxidation of highly doped aluminum under a certain temperature condition, so as to form the current confinement layer 30 in the P-type dbr 24. The current confinement layer 30 has an opening that defines a light emitting region Q of the light emitting mesa structure. The lengths of the current confinement layers on the two sides of the trench formed by the opening are equal. The alumina formed after oxidation has high impedance, the opening of the current confinement layer 30 is still made of aluminum-doped aluminum-gallium-arsenic material, and when current enters the light-emitting mesa structure, the current flows to the active layer through the opening in the current confinement layer 30. In the present embodiment, the current confinement layer 30 in each mesa structure is a circular ring structure, and when the mesa structure is rectangular in a plan view, the current confinement layer 30 may also be rectangular ring-shaped.

S140, forming an N-type ohmic layer on one side, far away from the substrate, of the N-type contact layer exposed by the groove; the distance between the N-type ohmic layer and the side wall of the groove is larger than zero.

Specifically, fig. 5 is a cross-sectional view of the structure in step S140 of the method for manufacturing a vertical cavity surface emitting laser according to the embodiment of the present invention, and referring to fig. 5, the N-type ohmic layer 40 is defined by selectively using evaporation, sputtering, electroplating, or chemical plating according to product design, shape processing requirements, and other technical manners of different patterns. Before forming the N-type ohmic layer 40, a photoresist layer may be formed in the trench, and then the photoresist layer may be patterned by exposure and development to form a photoresist pattern. And removing the photoresist layer after depositing the metal layer based on the photoresist pattern, so that the metal layer deposited on the photoresist layer is removed simultaneously when the photoresist layer is removed. The metal layer at the position of the opening of the photoresist pattern is left, and the remaining metal layer forms the N-type ohmic layer 40. The distance from the N-type ohmic layer 40 to the side wall of the groove is larger than zero, so that the N-type ohmic layer 40 is prevented from being in direct contact with the light-emitting mesa structure.

S150, forming a first passivation layer on one side of the semiconductor epitaxial structure, which is far away from the substrate, and on the side wall and the bottom of the groove; and etching the first passivation layer positioned on one side of the N-type ohmic layer, which is far away from the substrate, and the first passivation layer positioned on one side of the P-type contact layer, which is far away from the substrate, in the light-emitting mesa structure in the same etching process so as to form a first opening on one side of the N-type ohmic layer, which is far away from the substrate, to expose the N-type ohmic layer, and form a second opening on one side of the P-type contact layer, which is far away from the substrate, in the light-emitting mesa structure to expose the P-type contact layer.

Specifically, fig. 6 to 7 are cross-sectional views of the structure of step S150 in the method for manufacturing a vertical cavity surface emitting laser according to the embodiment of the present invention, and referring to fig. 6 to 7, after the current confinement layer 30 and the N-type ohmic layer 40 are formed, an insulating layer, i.e., a first passivation layer 50, is formed on the epitaxial structure. A first passivation layer 50 is formed covering the surface of the semiconductor epitaxial structure 20 on the side away from the substrate 10 and the sidewalls and bottom of the trench. The material of the first passivation layer 50 may be silicon nitride or silicon oxide or other insulating material, and may be formed by chemical vapor deposition. The first passivation layer 50 may protect the current confinement layer 30 and may also effectively isolate adjacent mesa structures. After forming the first passivation layer 50 on the side of the semiconductor epitaxial structure 20 away from the substrate 10 and the sidewall and bottom of the trench, the first passivation layer 50 on the side of the N-type ohmic layer 40 away from the substrate 10 and the first passivation layer 50 on the side of the P-type contact layer 25 away from the substrate 10 in the light emitting mesa structure are etched in the same etching process to form a first opening a exposing the N-type ohmic layer 40 on the side of the N-type ohmic layer 40 away from the substrate 10 and a second opening B exposing the P-type contact layer 25 on the side of the P-type contact layer 25 away from the substrate 10 in the light emitting mesa structure. According to the embodiment of the invention, the first passivation layer 50 on the side of the N-type ohmic layer 40 far away from the substrate 10 is etched in one etching process, so that the times of the opening etching process are reduced, the process time is shortened, and the preparation phase ratio of the laser is improved.

And S160, in the same metal deposition process, forming a first electrode layer in the first opening and sequentially forming a P-type ohmic layer and a second electrode layer in the second opening.

Specifically, fig. 8 is a cross-sectional view of the structure of step S160 in the method for manufacturing a vertical cavity surface emitting laser according to the embodiment of the present invention, and referring to fig. 8, in the same metal deposition process, a first electrode layer 60 is formed in the first opening a, and a P-type ohmic layer and a second electrode layer 70 are sequentially formed in the second opening B (the first electrode layer and the second electrode layer are exemplarily shown in fig. 8, and the P-type ohmic layer is not shown), and the formed first electrode layer 60 is not in contact with the second electrode layer 70. The same metal deposition process may be understood as a manner in which the first electrode layer 60 in the first opening a and the P-type ohmic layer and the second electrode layer 70 in the second opening B are formed by simultaneously depositing the same metal material. It is also possible to apply a photoresist layer before performing the metal deposition process, and form a photoresist pattern after exposing and developing the photoresist layer. So that the side of the first passivation layer 50 facing away from the substrate 10 in the region where there is no contact between the first electrode layer 60 and the second electrode layer 70 is covered with a photoresist layer. After depositing the metal layer, the photoresist layer is removed and the metal layer attached to the photoresist layer is removed, so that the first electrode layer 60 and the second electrode layer 70 which are not in contact with each other can be formed. A single metal deposition process may bond the N-type ohmic layer 40 to the cathode pad metal (first electrode layer 60), the P-type ohmic layer to the P-type contact layer 25, and the P-type ohmic layer to the anode pad metal (second electrode layer 70). In the formed laser, the P-type ohmic layer and the N-type ohmic layer 40 are located on the same side of the substrate 10. The number of light shades and the number of processes are reduced, the times of metal deposition processes are reduced, the preparation time of the laser is shortened, the preparation efficiency of the laser is improved, metal consumables can be reduced, and the preparation cost is reduced.

The method for manufacturing a vertical cavity surface emitting laser provided by the embodiment of the invention forms a first opening exposing the N-type ohmic layer at one side of the N-type ohmic layer far away from the substrate and a second opening exposing the P-type contact layer at one side of the P-type contact layer far away from the substrate in the light-emitting mesa structure by etching the first passivation layer at one side of the N-type ohmic layer far away from the substrate and the first passivation layer at one side of the P-type contact layer far away from the substrate in the light-emitting mesa structure, so that the times of the opening etching process are reduced, and in the same metal deposition process, the first electrode layer is formed in the first opening and the P-type ohmic layer and the second electrode layer are sequentially formed in the second opening, so that the times of the metal deposition process and the amount of metal consumables are reduced, thereby improving the manufacturing efficiency of the laser and shortening the manufacturing time of the laser, the preparation cost is reduced.

Optionally, a second passivation layer is further included between the first passivation layer located on the side of the semiconductor epitaxial structure far away from the substrate and the semiconductor epitaxial structure; before the semiconductor epitaxial structure is etched to form the groove, the method further comprises the following steps:

and forming a second passivation layer on one side of the semiconductor epitaxial structure far away from the substrate, and etching the second passivation layer in the region where the groove is located to expose the semiconductor epitaxial structure to be etched.

Specifically, fig. 9 is a cross-sectional view of a structure in which a second passivation layer 80 is formed in the method for manufacturing a vertical cavity surface emitting laser according to the embodiment of the present invention, and referring to fig. 9, before the semiconductor epitaxial structure 20 is etched to form the trench, the second passivation layer 80 is formed on a side of the semiconductor epitaxial structure 20 away from the substrate 10, where the second passivation layer 80 may be made of silicon nitride or silicon oxide or other insulating materials, and may be formed by chemical vapor deposition. The second passivation layer 80 is used for protecting the epitaxial layer structure, preventing external water and oxygen from damaging the surface of the epitaxial layer structure, and meeting the preparation conditions of high performance, high appearance processing requirements and the like of the laser. Fig. 10 is a structural cross-sectional view illustrating the second passivation layer etched in the method for manufacturing a vertical cavity surface emitting laser according to the embodiment of the present invention, and referring to fig. 10, after the second passivation layer 80 located in the region where the trench is located is etched to expose the semiconductor epitaxial structure 20 to be etched, the semiconductor epitaxial structure 20 is continuously etched to form the trench.

Optionally, the number of the light-emitting mesa structures is 1; forming an N-type ohmic layer on the exposed side of the N-type contact layer from the substrate in the trench includes:

and forming an N-type ohmic layer on one side of the N-type contact layer, which is far away from the substrate, along the extending direction of the groove surrounding the light-emitting mesa structure.

Specifically, fig. 11 is a top view of a vertical cavity surface emitting laser according to an embodiment of the present invention, a cross-sectional view of a structure taken along a section line C1-C2 in fig. 11 is a cross-sectional view of the structure shown in fig. 8, and referring to fig. 11 in combination with fig. 8, a light emitting mesa structure in the vertical cavity surface emitting laser may be single, and a trench may be formed to surround the light emitting mesa structure. If the light emitting mesa structure is a cylindrical structure, the trench may be an annular structure. And forming an N-type ohmic layer 40 on one side of the N-type contact layer 21 far away from the substrate 10 along the extending direction of the groove around the light-emitting mesa structure, wherein the N-type ohmic layer 40 is arranged around the light-emitting mesa structure to form an arc-shaped N-type ohmic layer 40. Thus, in fig. 11, the N-type ohmic layers 40 are positioned at opposite sides of the light emitting mesa structure. It should be noted that, after forming the first passivation layer 50 on the side of the semiconductor epitaxial structure 20 away from the substrate 10 and the sidewall and the bottom of the trench, etching the first passivation layer 50 to form the first opening a exposing the N-type ohmic layer 40 on the side of the N-type ohmic layer 40 away from the substrate 10, and in the process of forming the second opening B exposing the P-type contact layer 25 on the side of the P-type contact layer 25 away from the substrate 10 in the light emitting mesa structure, the first opening a and the second opening B correspond to annular openings, so in fig. 11, the upper portions of the N-type ohmic layer 40 on the two opposite sides of the light emitting mesa structure are provided with the first opening a; in the light emitting mesa structure, the number of the second openings B formed on the side of the P-type contact layer 25 away from the substrate 10 is also two.

Optionally, the number of the light-emitting mesa structures is multiple; forming an N-type ohmic layer on the exposed side of the N-type contact layer from the substrate in the trench includes:

and forming a common N-type contact layer in the grooves on the same side of the light-emitting mesa structures.

Specifically, fig. 12 is a top view of another vertical cavity surface emitting laser according to an embodiment of the present invention, and referring to fig. 12, a plurality of light emitting mesa structures may be formed in the vertical cavity surface emitting laser, and a plurality of light emitting mesa structures are formed by forming a plurality of trenches. In fig. 12, 8 light emitting mesa structures are exemplarily drawn. The N-type ohmic layer 40 is formed in the trenches on the same side of the 8 light emitting mesa structures, and the N-type ohmic layer 40 may be in the shape of a stripe. After a first passivation layer 50 is formed on the side of the semiconductor epitaxial structure 20 away from the substrate 10 and on the sidewall and the bottom of the trench, the first passivation layer 50 is etched to form a first opening a exposing the N-type ohmic layer 40 on the side of the N-type ohmic layer 40 away from the substrate 10, and in the process of forming a second opening B exposing the P-type contact layer 25 on the side of the P-type contact layer 25 away from the substrate 10 in the light emitting mesa structure, the first opening a is formed in a strip shape, and the second opening B is still formed in a ring shape. The first electrode layer 60 is a common electrode layer of 8 light-emitting mesa structures; the first electrode layer 60 is a cathode pad metal layer; the second electrode layer 70 formed in the region where the 8 light-emitting mesa structures are located is also a common electrode layer, the second electrode layer 70 is an anode pad metal layer, and the 8 light-emitting mesa structures are connected in parallel. The current signal flows to the P-type ohmic layer of each light emitting mesa structure through the anode pad metal layer, passes through the respective P-type distributed bragg reflector 24, quantum well layer 23, N-type distributed bragg reflector 22, flows to the common N-type ohmic layer 40 through the entire N-type contact layer 21, and flows out through the cathode pad metal layer, thereby forming a closed loop.

Fig. 13 is a cross-sectional view of a structure of fig. 12 taken along C3-C4, and referring to fig. 13, in a peripheral region where the light emitting mesa structure is formed, when the semiconductor epitaxial layer structure is etched, the N-type contact layer 21 may be partially etched on a side having the N-type contact layer 21, and the N-type dbr 22 may be partially etched on a region not having the N-type ohmic layer 40. Fig. 14 is a cross-sectional view of another structure of fig. 12 taken along C3-C4, and referring to fig. 14, in the peripheral region of the light emitting mesa structure formation position, when etching the semiconductor epitaxial layer structure, the N-type contact layer 21 may be etched entirely at the side having the N-type contact layer 21, and the N-type dbr 22 may be etched entirely at the region not having the N-type ohmic layer 40.

Referring to fig. 8, an embodiment of the present invention further provides a vertical cavity surface emitting laser, including:

a substrate 10 and a semiconductor epitaxial structure 20 located on one side of the substrate 10;

the semiconductor epitaxial structure 20 comprises an N-type contact layer 21, an N-type distributed Bragg reflection layer 22, a quantum well layer 23, a P-type distributed Bragg reflection layer 24 and a P-type contact layer 25 which are sequentially stacked on a substrate 10; the semiconductor epitaxial structure 20 includes a trench and a light emitting mesa structure surrounded by the trench; an N-type ohmic layer 40 of an exposed portion of the trench; the light emitting mesa structure includes a current confinement layer 30; the current confinement layer 30 has an opening for defining a light emitting region Q of the light emitting mesa structure;

the N-type ohmic layer 40 is positioned at the bottom of the groove; the distance from the N-type ohmic layer 40 to the side wall of the groove is larger than zero;

a first passivation layer 50, wherein the first passivation layer 50 is positioned on one side of the semiconductor epitaxial structure 20 far away from the substrate 10 and on the side wall and the bottom of the trench; the first passivation layer 50 includes a first opening a and a second opening B; the first opening A exposes the N-type ohmic layer 40, and the second opening B exposes the P-type contact layer 25 in the light emitting mesa structure; wherein the first opening A and the second opening B are formed in the same etching process;

a first electrode layer 60, a P-type ohmic layer and a second electrode layer 70, the first electrode layer 60 contacting the N-type ohmic layer 40 exposed by the first opening a; the P-type ohmic layer contacts the P-type contact layer 25 exposed by the second opening B; the second electrode layer 70 is positioned on the side of the P-type ohmic layer far away from the P-type contact layer 25; the N-type electrode layer, the P-type ohmic layer and the P-type electrode layer are formed in the same metal deposition process.

In the vertical cavity surface emitting laser provided in the embodiment of the present invention, the first passivation layer 50 includes a first opening a and a second opening B; the first opening A exposes the N-type ohmic layer 40, and the second opening B exposes the P-type contact layer 25 in the light emitting mesa structure; wherein the first opening A and the second opening B are formed in the same etching process; the first passivation layer 50 on the side, far away from the substrate 10, of the N-type ohmic layer 40 and the first passivation layer 50 on the side, far away from the substrate 10, of the P-type contact layer 25 in the light-emitting mesa structure are etched in the same etching process, so that a first opening A exposing the N-type ohmic layer 40 is formed on the side, far away from the substrate 10, of the N-type ohmic layer 40, and a second opening B exposing the P-type contact layer 25 is formed on the side, far away from the substrate 10, of the P-type contact layer 25 in the light-emitting mesa structure, and therefore the times of opening etching processes are reduced. In addition, the N-type electrode layer, the P-type ohmic layer and the P-type electrode layer of the vertical cavity surface emitting laser are formed in the same metal deposition process. By forming the first electrode layer 60 in the first opening a and the P-type ohmic layer and the second electrode layer 70 in the second opening B in sequence in the same metal deposition process, the number of times of the metal deposition process is reduced, and the amount of metal consumables is reduced, thereby improving the preparation efficiency of the laser, shortening the preparation time of the laser, and reducing the preparation cost.

Optionally, the vertical cavity surface emitting laser further includes:

and the second passivation layer is positioned between the semiconductor epitaxial structure and the first passivation layer and covers the surface of one side, far away from the substrate, of the semiconductor epitaxial structure.

Optionally, the N-type distributed bragg reflector and the P-type distributed bragg reflector are formed by laminating two material layers with different refractive indexes, namely an aluminum gallium arsenic material layer and a gallium arsenide material layer, or by laminating two material layers with different refractive indexes, namely an aluminum gallium arsenic material layer with a high aluminum component and an aluminum gallium arsenic material layer with a low aluminum component.

Optionally, the number of the light-emitting mesa structures includes a plurality of light-emitting mesa structures, and the N-type ohmic layer is a common N-type ohmic layer and is located in the trench on the same side of the plurality of light-emitting mesa structures.

It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.