Vertical cavity surface emitting laser and preparation method thereof

Abstract

The invention belongs to the technical field of semiconductor laser processes, and discloses a vertical cavity surface emitting laser and a preparation method thereof, and the preparation method comprises the following steps for preparing an oxidation limiting layer and an antireflection film of the laser: placing an epitaxial structure in an oxidizing gas environment, and oxidizing an antireflection precursor layer to form the antireflection film, the oxidized part limits the precursor layer to form an oxidation limiting layer, and the oxidation limiting layer is used for limiting current and / or limiting a light field. Therefore, the anti-reflection film can be formed by oxidizing the anti-reflection precursor layer in the epitaxial structure, independent preparation of the anti-reflection film is not needed, the laser preparation process is simplified, meanwhile, the contact surface structure of the anti-reflection precursor layer prepared in the epitaxial structure and the adjacent layer is more compact, the interface bonding strength after oxidation growth is better, and the laser yield is improved. And the risk that the antireflection film falls off is effectively reduced. In addition, the oxidation limiting precursor layer obtains an oxidation limiting layer capable of limiting current and / or limiting a light field, and the overall performance of the laser is guaranteed.

Description

Technical Field

[0001] The present application belongs to the field of semiconductor laser process technology, and in particular, relates to a vertical cavity surface emitting laser and a preparation method thereof. Background Art

[0002] Vertical-Cavity Surface-Emitting Laser (VCSEL) is a semiconductor laser with very broad application prospects. Compared with traditional edge-emitting lasers (EEL), it has a smaller far-field divergence angle, a narrow and round emitted beam, is easy to couple with optical fibers, has a low threshold current and a high modulation frequency, and can operate in a single longitudinal mode over a wide temperature and current range.

[0003] How to simplify the preparation process of straight-cavity surface emitting lasers and reduce the preparation cost is an urgent problem to be solved by those skilled in the art. Summary of the invention

[0004] The purpose of the present application is to provide a vertical cavity surface emitting laser and a preparation method thereof, which can simplify the preparation process of the vertical cavity surface emitting laser while reducing the preparation cost, thereby improving the efficiency of the entire preparation process.

[0005] In a first aspect, an embodiment of the present application provides a method for preparing a vertical cavity surface emitting laser, comprising the following steps for preparing an oxidation confinement layer and an anti-reflection film of the laser:

[0006] The epitaxial structure is placed in an oxidizing gas environment, the antireflection precursor layer is oxidized to form the antireflection film, and a portion of the limiting precursor layer is oxidized to form the oxidized limiting layer, wherein the oxidized limiting layer is used to constrain current and / or limit light field.

[0007] It can be seen that the technical solution provided by the present application can form an anti-reflection film by oxidizing the anti-reflection precursor layer in the epitaxial structure, without the need to prepare the anti-reflection film separately, simplifying the laser preparation process, and at the same time, the contact surface structure between the anti-reflection precursor layer prepared in the epitaxial structure and the adjacent layer is more compact, and the interface bonding strength after oxidation growth is better, which effectively reduces the risk of the anti-reflection film falling off. In addition, while oxidizing the anti-reflection precursor layer, the oxidation restriction precursor layer is oxidized to obtain an oxidized restriction layer that can constrain current and / or limit the light field, and then the light transmittance is increased by the anti-reflection film, and the current can be constrained and / or the light field can be limited, thereby ensuring the overall performance of the laser.

[0008] In a possible implementation of the first aspect, the anti-reflection precursor layer is prepared based on a first preset material, the first preset material includes an aluminum element whose proportion exceeds a preset first threshold, and the first preset material also includes at least one of a gallium element, an indium element, and an arsenic element.

[0009] Thus, a dense and transparent aluminum oxide anti-reflection film can be oxidized through an anti-reflection precursor layer having a high aluminum component, thereby preparing a laser with better anti-reflection effect. Furthermore, the anti-reflection film composition can be fine-tuned by at least one of gallium, indium and arsenic elements to obtain a laser with expected performance.

[0010] In a possible implementation manner of the first aspect, the first preset material is unintentionally doped AlGaAs.

[0011] Therefore, the anti-reflection precursor layer adopts a material with a high aluminum component, which is oxidized to form an anti-reflection film with a low refractive index and high transmittance. It is obtained by directly oxidizing the epitaxial structure without the need for delayed anti-reflection film preparation, thereby ensuring the performance of the laser while reducing costs.

[0012] In a possible implementation of the first aspect, the epitaxial structure includes a substrate, a Bragg reflection layer, and the anti-reflection precursor layer arranged in sequence, the Bragg reflection layer includes an upper Bragg reflection layer and a lower Bragg reflection layer, and at least one confinement precursor layer is included between the upper Bragg reflection layer and the lower Bragg reflection layer, and an active region is arranged between the lower Bragg reflection layer and the confinement precursor layer; wherein the active region is a multi-quantum well structure, and the central wavelength of the emission spectrum of the quantum well matches the wavelength of the vertical cavity surface emitting laser.

[0013] Therefore, due to its confinement effect on electrons and holes, the multi-quantum well structure makes the energy level of photon emission more concentrated and can produce a narrower emission spectrum. This makes the prepared laser have higher spectral purity and narrower spectral linewidth.

[0014] In a possible implementation manner of the first aspect, a first matching layer is disposed on a side of the active region adjacent to the confinement precursor layer, and a second matching layer is disposed on a side of the active region adjacent to the lower Bragg reflection layer;

[0015] The first matching layer and the second matching layer are used to adjust the wavelength of the vertical cavity surface emitting laser.

[0016] Therefore, the active region adopts a multi-quantum well structure, which can effectively improve the tuning bandwidth of the laser. In addition, there are matching layers on the upper and lower sides of the multi-quantum well that can be used to adjust the laser wavelength so that the central wavelength of the emission spectrum matches the laser wavelength.

[0017] In a possible implementation manner of the first aspect, the Bragg reflective layer includes a plurality of reflective layer pairs, the doping concentrations of two reflective layer pairs adjacent to the active region are lower than the doping concentrations of other reflective layer pairs, the first reflective layer and the second reflective layer in the reflective layer pair have different refractive indices, and the upper Bragg reflective layer and the lower Bragg reflective layer have different reflectivities.

[0018] Therefore, by efficiently reflecting light of a specific wavelength through reflective layers with different refractive indices, the laser light can be accumulated to realize the laser function. In addition, it is ensured that the light is less reflected and the transmittance is increased within a certain wavelength range.

[0019] In a possible implementation of the first aspect, the first reflective layer is prepared based on a second preset material, and the second reflective layer is prepared based on a third preset material, and the second preset material and the third preset material both include aluminum and gallium elements, the proportion of aluminum in the second preset material is greater than the proportion of aluminum in the third preset material, and the proportion of gallium in the second preset material is less than the proportion of gallium in the third preset material.

[0020] Therefore, by changing the aluminum and gallium components, the refractive index of the inner sublayers of the reflective layer, namely the first reflective layer and the second reflective layer, can be adjusted, which simplifies the difficulty of the preparation process.

[0021] In a possible implementation manner of the first aspect, the epitaxial structure further includes a contact layer, the contact layer is disposed between the upper Bragg reflector layer and the antireflection precursor layer, and before placing the epitaxial structure in an oxidizing gas environment, oxidizing the antireflection precursor layer to form the antireflection film, and oxidizing a portion of the restriction precursor layer to form the oxidized restriction layer, the method further includes:

[0022] Acquiring the epitaxial structure;

[0023] Photolithography a preset shape on the anti-reflection precursor layer; wherein the preset shape is determined according to the applied electric field of the vertical cavity surface emitting laser;

[0024] Corroding or etching the antireflection precursor material in the preset shape to the contact layer;

[0025] growing a conductive material on a side of the antireflection precursor layer away from the contact layer;

[0026] Stripping or corroding the conductive material outside the preset shape so as to form a first electrode composed of the conductive material within the preset shape;

[0027] The epitaxial structure is photolithographically formed into a laser mesa.

[0028] Therefore, after the epitaxial structure is photolithographically formed into the laser mesa, the size of the working area of ​​the laser is limited, which provides a good basis for the oxidation depth (corresponding to the oxidation aperture size) of the subsequent oxidation restriction layer.

[0029] In a possible implementation manner of the first aspect, after placing the epitaxial structure in an oxidizing gas environment, oxidizing the antireflection precursor layer to form the antireflection film, and oxidizing a portion of the limiting precursor layer to form the oxidized limiting layer, the method further comprises:

[0030] growing an insulating layer on the laser mesa;

[0031] Etching an electrode window on the insulating layer;

[0032] growing the conductive material on a side of the insulating layer facing away from the laser mesa;

[0033] Stripping or corroding the conductive material outside the electrode window, so that the conductive material in the electrode window constitutes a current carrier of the first electrode, and the current carrier is electrically connected to the first electrode;

[0034] A conductive material is grown on a side of the substrate facing away from the Bragg reflection layer to obtain a second electrode.

[0035] Therefore, by introducing the energized carrier, when the laser is working, the electrode probe can avoid direct contact with the first electrode, thereby causing the problem of changes in the uniformity of the electric field provided in the laser. Applying an electrical signal through the energized carrier can obtain a more stable output laser.

[0036] In a second aspect, an embodiment of the present application provides a vertical cavity surface emitting laser, which is obtained by the above-mentioned method for preparing the vertical cavity surface emitting laser.

[0037] It should be noted that the beneficial effects of the second aspect mentioned above can be found in the relevant description of the first aspect mentioned above, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0039] Figure 1 A schematic diagram of an epitaxial structure provided in an embodiment of the present application;

[0040] Figure 2 A wavelength matching schematic diagram provided in an embodiment of the present application;

[0041] Figure 3 A schematic structural diagram of an epitaxial structure provided in another embodiment of the present application;

[0042] Figure 4 A schematic diagram of a structure diagram of another epitaxial structure provided in an embodiment of the present application;

[0043] Figure 5 A schematic flow chart of a method for preparing a vertical cavity surface emitting laser provided in an embodiment of the present application;

[0044] The figure numbers are as follows: 1 is the anti-reflection precursor layer, 2 is the contact layer, 3 is the upper DBR, 4 is the limiting precursor layer, 5 is the active area, 6 is the lower DBR, 7 is the substrate, 8 is the second electrode, 30 is the laser wavelength, 31 is the emission spectrum center wave, 40 is the first electrode, 41 is the anti-reflection film, 42 is the oxidation limiting layer, and 43 is the oxidation aperture. DETAILED DESCRIPTION

[0045] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0046] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, wholes, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or combinations thereof.

[0047] It should also be understood that the term “and / or” used in the specification and appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0048] As used in the specification and appended claims of this application, the term "if" can be interpreted as "when" or "uponce" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" can be interpreted as meaning "uponce it is determined" or "in response to determining" or "uponce [described condition or event] is detected" or "in response to detecting [described condition or event]", depending on the context.

[0049] In addition, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0050] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0051] In order to enable those skilled in the art to better understand the present application, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0052] Vertical-Cavity Surface-Emitting Laser (VCSEL) is a semiconductor whose laser is emitted perpendicular to the top surface. Compared with traditional edge-emitting lasers (EEL), VCSEL has a smaller far-field divergence angle, a narrow and round emitted beam, easy fiber coupling, low threshold current, high modulation frequency, and easy realization of large-scale arrays and optoelectronic integration. Therefore, VCSEL has broad application prospects and can be used in different fields such as laser processing, medical beauty, environmental testing, drones and sweeping robots.

[0053] In recent years, with the rapid development of big data application technologies such as the Internet of Things, cloud computing, e-commerce, social networks, virtual reality, online games and videos, various new Internet applications have emerged in an endless stream, which have had a profound impact on human society. As a result, the amount of data generated has led to an exponentially rapid increase in demand for communication capacity and computing power.

[0054] The 850nm VCSEL chip is one of the more mature vertical cavity surface emitting lasers in the world that is widely used in the market. In addition to its important application in the field of optical fiber communications, VCSEL has outstanding characteristics in information transmission capacity, sensor control, real-time response, and power consumption. It can bring differentiated high performance to smart phones, consumer products, automotive LiDAR, 8K ultra-high-definition TVs, VR virtual reality, and industrial applications. With the continuous decline in the cost of VCSEL devices and the continuous increase in demand for Internet of Vehicles and intelligent driving, the demand for automotive LiDAR is increasing rapidly. Compared with traditional scanning radars, semiconductor LiDARs represented by VCSELs have obvious advantages in controllability and cost, which can significantly reduce the cost of traditional LiDARs and accelerate the application and promotion of automotive LiDARs.

[0055] A feasible vertical cavity surface emitting laser preparation scheme includes: semiconductor material epitaxy, table production, wet oxygen oxidation, insulation layer deposition, window etching, P electrode production, anti-reflection film production, thinning, N electrode production and other post-processing. Among them, in the production of window anti-reflection film, the anti-reflection film needs to be produced separately. Specifically, silicon nitride material is used, which often introduces stress between the semiconductor material and falls off. The separate production process steps are complicated and will also increase the production cost of the laser.

[0056] In order to simplify the preparation process of a vertical cavity surface emitting laser and reduce the preparation cost, an embodiment of the present application provides a preparation method of a vertical cavity surface emitting laser, by oxidizing an epitaxial material, oxidizing the top anti-reflection precursor layer in the epitaxial material to form an anti-reflection film, and oxidizing the middle limiting precursor layer to form an oxidized limiting layer. Thus, there is no need to additionally prepare an anti-reflection film. In addition to obtaining the anti-reflection film by simultaneously oxidizing the anti-reflection precursor layer and the limiting precursor layer, an oxidized limiting layer that can constrain current and / or limit the light field is also obtained. In addition to simplifying the preparation process of the vertical cavity surface emitting laser, the cost is reduced and the overall performance of the laser is guaranteed.

[0057] Specifically, a method for preparing a vertical cavity surface emitting laser provided in an embodiment of the present application includes the following steps for preparing an oxidation restriction layer and an anti-reflection film of the laser: placing the epitaxial structure in an oxidizing gas environment, oxidizing the anti-reflection precursor layer to form an anti-reflection film, oxidizing a portion of the restriction precursor layer to form an oxidation restriction layer, and the oxidation restriction layer is used to constrain current and / or limit the light field.

[0058] Figure 1 A schematic diagram of an epitaxial structure provided in an embodiment of the present application is shown in FIG. Figure 1As shown, in a specific embodiment, the epitaxial structure for preparing a vertical cavity surface emitting laser is provided with a substrate 7, a Distributed Bragg Reflector (DBR) and an anti-reflection precursor layer 1 in sequence, wherein the DBR includes an upper DBR 3 and a lower DBR 6, and at least one limiting precursor layer 4 is provided between the upper DBR 3 and the lower DBR 6.

[0059] It is understandable that (relative to Figure 1 The top antireflection precursor layer 1 (in the direction) is used to form an antireflection film for increasing the transmittance, while the limiting precursor layer 4 is used to prepare an oxidized limiting layer for constraining current and / or limiting the light field.

[0060] Among them, the material of the anti-reflective precursor layer 1 includes elements that can be oxidized, and the proportion of the elements that can be oxidized is relatively high. For example, the material of the anti-reflective precursor layer 1 includes aluminum elements with a proportion exceeding a threshold, that is, it includes a high aluminum component. In addition, the material of the anti-reflective precursor layer 1 can also include other elements such as gallium and indium, and the present application does not make specific limitations on this.

[0061] In fact, the material of the limiting precursor layer 4 used to prepare the oxidation limiting layer also includes oxidizable elements, thereby enabling the oxidation limiting layer to be prepared while preparing the antireflection film. The elements of the limiting precursor layer 4 material are not specifically limited in this application.

[0062] After obtaining the epitaxial structure, Figure 1 As shown, the epitaxial structure is placed in an oxidizing gas environment. Since the materials of the anti-reflection precursor layer 1 and the limiting precursor layer 4 include oxidizable elements, in the oxidizing gas environment, the top anti-reflection precursor layer 1 is oxidized to form an anti-reflection film, and the middle limiting precursor layer 4 is oxidized to form an oxidized limiting layer for constraining current and / or limiting the light field.

[0063] When the epitaxial structure is placed in an oxidizing gas environment, the top antireflection precursor layer 1 begins to oxidize from the portion in contact with the gas. After the antireflection precursor layer 1 is completely oxidized, the physical properties of the resulting antireflection film will have a direct impact on the performance of the laser (or, the antireflection performance of the antireflection film). For example, among the optical parameters, the transmittance / absorbance will affect the transmission efficiency of the antireflection film, and the refractive index will affect the reflection / refraction ratio at the interface; and among the dimensional parameters, the thickness will affect the optical path of part of the laser in the antireflection film.

[0064] Therefore, for a vertical cavity surface emitting laser with expected parameters, the expected physical properties of its antireflection film can be defined, and on this basis, the appropriate material and size of the antireflection precursor layer 1 are set to ensure the performance of the antireflection film obtained after oxidation.

[0065] Unlike the anti-reflection precursor layer 1, the limiting precursor layer 4 is arranged in the DBR, and its oxidation will start from the part of the side of the limiting precursor layer 4 that is in contact with the gas. It is worth noting that the present application does not limit the thickness of the limiting precursor layer 4, but since the area of ​​the limiting precursor layer 4 in contact with the gas is much smaller than the area of ​​the anti-reflection precursor layer 1 in contact with the gas, during the oxidation process, after the anti-reflection precursor layer 1 is completely oxidized, the limiting precursor layer 4 is not completely oxidized, and the resulting oxidized limiting layer includes an oxidized part and an unoxidized part, and the unoxidized part surrounded by the oxidized part is called the oxidation aperture of the laser.

[0066] In a specific embodiment, in order to ensure that light can completely pass through the anti-reflection film to improve the transmittance, the anti-reflection precursor layer 1 should be completely oxidized to obtain the anti-reflection film. In actual preparation, the anti-reflection precursor layer 1 is often set very thin. For example, the thickness of the anti-reflection precursor layer 1 is 50nm to 300nm, which is easy to be completely oxidized. It is worth noting that the thickness of the anti-reflection precursor layer 1 is preferably in the range of 50nm to 300nm. In fact, this application does not specifically limit the thickness of the anti-reflection precursor layer 1. The anti-reflection film obtained by oxidation has a lower refractive index and an increased transmittance. In addition, as a preferred embodiment, the optical thickness of the anti-reflection film is one-quarter of the effective wavelength of the laser, wherein the effective wavelength refers to the wavelength in the air divided by the refractive index of the anti-reflection film.

[0067] It is worth noting that the size of the oxidation aperture is closely related to the power consumption and efficiency of the VCSEL. For example, at room temperature, the larger the oxidation aperture of the VCSEL, the higher the power conversion efficiency of the VCSEL. If the ambient temperature rises, the larger the oxidation aperture of the VCSEL, the more obvious the increase in power loss will be. Therefore, it is very important to prepare a suitable oxidation aperture for VCSEL. In the embodiment of the present application, the size of the oxidation aperture can be controlled according to the duration of the oxidation restriction precursor layer 4, the pressure of the oxidation gas environment, and the components of the oxidation gas environment (for example, the oxidizing property of the oxidant).

[0068] For example, if you want to get the smallest possible oxidation aperture, then after the antireflection precursor layer 1 is completely oxidized to form an antireflection film, continue to oxidize for a period of time, thereby ensuring that the precursor layer 4 is oxidized as much as possible to obtain a smaller oxidation aperture. In fact, the requirements for VCSEL oxidation apertures are different in different application scenarios, and VCSELs can be prepared according to actual business needs.

[0069] After forming the anti-reflection film and the oxidation aperture, further, electrodes are grown on the epitaxial structure to obtain the VCSEL. In an optional embodiment, the electrodes include a P electrode, a current carrier of the P electrode, and an N electrode.

[0070] It is worth noting that when controlling the duration of oxidation of the limiting precursor layer 4, the pressure of the oxidizing gas environment and the components of the oxidizing gas environment, it should be ensured that under these conditions, the antireflection precursor layer 1 can be completely oxidized to form an antireflection film.

[0071] It can be seen that the technical solution provided by the present application can form an anti-reflection film by oxidizing the anti-reflection precursor layer in the epitaxial structure, without the need to prepare the anti-reflection film separately, simplifying the laser preparation process, and at the same time, the contact surface structure between the anti-reflection precursor layer prepared in the epitaxial structure and the adjacent layer is more compact, and the interface bonding strength after oxidation growth is better, which effectively reduces the risk of the anti-reflection film falling off. In addition, while oxidizing the anti-reflection precursor layer, the oxidation restriction precursor layer is oxidized to obtain an oxidized restriction layer that can constrain current and / or limit the light field, and then the light transmittance is increased by the anti-reflection film, and the current can be constrained and / or the light field can be limited, thereby ensuring the overall performance of the laser.

[0072] As a preferred embodiment, the anti-reflection precursor layer is prepared based on a first preset material, the first preset material includes aluminum elements whose proportion exceeds a preset first threshold, and the first preset material also includes at least one of gallium elements, indium elements and arsenic elements.

[0073] In a specific embodiment, the high aluminum component is oxidized to form Al2O3, and Al2O3 is used as an anti-reflection film to reduce the high refractive index of about 3 to a low refractive index of about 1.75, thereby reducing the refractive index and improving the transmittance.

[0074] In another preferred embodiment, the first preset material is unintentionally doped AlGaAs, the thickness may be 50nm-300nm, the aluminum component ratio may be 0.95-0.99, and after oxidation, low refractive index Al2O3 is formed to serve as an anti-reflection film, wherein unintentional doping means that no dopants are introduced during the preparation of the material or device, but unintentional impurities may exist in the material as a small amount of dopants.

[0075] In the method for preparing a vertical cavity surface emitting laser provided in the embodiment of the present application, the anti-reflection precursor layer adopts a material with a high aluminum component, which is oxidized to form an anti-reflection film with a low refractive index and high transmittance, and is obtained by directly oxidizing the epitaxial structure without the need for preparing a separate anti-reflection film, thereby ensuring the laser performance while reducing costs.

[0076] In a specific embodiment, Figure 1 As shown, the epitaxial structure further includes an active region 5 disposed adjacent to the confinement precursor layer 4; wherein the active region 5 is a multi-quantum well structure, and the central wavelength of the emission spectrum of the quantum well matches the wavelength of the vertical cavity surface emitting laser.

[0077] Figure 2 A wavelength matching schematic diagram provided in an embodiment of the present application is shown in FIG. Figure 2 As shown, 30 is the laser wavelength, and 31 is the emission spectrum center wave. Specifically, the matching of the emission spectrum center wavelength of the quantum well with the wavelength of the vertical cavity surface emitting laser means that there is an intersection between the peak of the emission spectrum center wave 31 and the center of the total wavelength of the laser wavelength 30.

[0078] In practical applications, there will inevitably be certain errors. Therefore, when the central wavelength of the emission spectrum of the quantum well matches the wavelength of the vertical cavity surface emitting laser, the difference between the peak value of the central wave 31 of the emission spectrum and the middle value of the wavelength of the laser wavelength 30 is required to be within a preset range.

[0079] The active region 5 may be a multi-quantum well structure such as InGaAs / GaAs, InGaAs / AlGaAs, InGaAs / GaAsP, etc., which is not specifically limited in this application.

[0080] A first matching layer is disposed on the side of the active region 5 adjacent to the confinement precursor layer 4 , and a second matching layer is disposed on the side adjacent to the Bragg reflection layer. The first matching layer and the second matching layer are used to adjust the wavelength of the vertical cavity surface emitting laser.

[0081] The preparation method of the vertical cavity surface emitting laser provided in the embodiment of the present application adopts a multi-quantum well structure in the active region, which can effectively improve the tuning bandwidth of the laser. In addition, matching layers are provided on the upper and lower sides of the multi-quantum well to adjust the laser wavelength so that the central wavelength of the emission spectrum matches the laser wavelength.

[0082] In implementation, the DBR includes an upper DBR 3 and a lower DBR 6, and both the upper DBR 3 and the lower DBR 6 are composed of a plurality of reflection layer pairs, and the refractive indexes of the first reflection layer and the second reflection layer in the reflection layer pair are different.

[0083] In a preferred embodiment, the upper DBR 3 may include 10 to 30 pairs of Al 0.1 Ga 0.9 As / Al 0.9 Ga 0.1 As reflective layer pairs, and the optical thickness of each layer is one quarter of the laser wavelength. It should be noted that the present application does not specifically limit the specific elements, element contents, and number of reflective layer pairs of the upper DBR 3 reflective layer.

[0084] The present application does not specifically limit the doping concentration of the upper DBR 3. In practical applications, the two reflective layers adjacent to the active region 5 are preferably lightly doped, and the P-type doping concentration is preferably not greater than 5*10 17 / cm 3 , the doping concentration range of other reflective layers is preferably 5*10 17 / cm 3 Up to 5*10 18 / cm 3 .

[0085] The lower DBR 6 includes 30 to 50 pairs of Al 0.1 Ga 0.9 As / Al 0.9 Ga 0.1 As reflective layer, each layer has an optical thickness of one quarter of the laser wavelength. Similarly, the present application does not specifically limit the specific elements, element contents, and number of reflective layer pairs of the lower DBR 6 reflective layer.

[0086] As for the doping concentration of the lower DBR 6, the two reflective layers adjacent to the active area 5 are lightly doped, and the N-type doping concentration is not greater than 5*10 17 / cm 3 , the doping concentration range of other reflective layers is 5*10 17 / cm 3 Up to 5*10 18 / cm 3 It is worth noting that, in an optional embodiment, there is a gradient of doping concentration between the reflective layer pairs, that is, a symmetrical gradient centered on the active area 5. This includes a gradient of doping concentration between two reflective layers adjacent to the active area 5 and other reflective layer pairs, and a gradient of doping concentration between different reflective layers between other reflective layer pairs.

[0087] It is worth noting that, no matter the upper DBR 3 or the lower DBR 6, the refractive indexes of the first reflective layer and the second reflective layer in each reflective layer pair are different, and the DBR can be understood as a structure composed of two materials with different refractive indices arranged alternately in the form of ABAB.

[0088] In addition, it should be noted that the upper DBR 3 and the lower DBR 6 have different refractive indices. Usually, the lower DBR 6 has a reflectivity of 99.9%, and the upper DBR 3 has a reflectivity of 99.5%.

[0089] In addition, the first reflective layer is prepared based on the second preset material, the second reflective layer is prepared based on the third preset material, and the second preset material and the third preset material both include aluminum and gallium, the aluminum content of the second preset material is greater than that of the third preset material, and the gallium content of the second preset material is less than that of the third preset material. That is, it can be understood that the sub-reflective layer within the reflective layer pair has a gradient aluminum component feature, that is, there is a gradient between material A and material B. In fact, there is also a gradient aluminum component in material A between different layers, and similarly, there is also a gradient component in material B between different layers.

[0090] In a specific embodiment, the epitaxial structure further includes a contact layer, which is disposed between the upper Bragg reflector layer and the antireflection precursor layer. After obtaining the epitaxial structure, the epitaxial structure is placed in an oxidizing gas environment, the antireflection precursor layer is oxidized to form an antireflection film, and before the oxidation of a portion of the restriction precursor layer to form an oxidation restriction layer is performed, the following steps are further included:

[0091] obtaining an epitaxial structure;

[0092] Photolithography a preset shape on the anti-reflection precursor layer; wherein the preset shape is determined according to the applied electric field of the vertical cavity surface emitting laser;

[0093] Corroding or etching the antireflection precursor material in a preset shape to the contact layer;

[0094] Growing a conductive material on the side of the antireflection precursor layer facing away from the contact layer;

[0095] Stripping or corroding the conductive material outside the preset shape so as to form a first electrode composed of the conductive material within the preset shape;

[0096] The laser mesa is formed by photolithographic epitaxial structure.

[0097] Figure 3 This is a schematic diagram of an epitaxial structure provided in another embodiment of the present application. In a specific embodiment, the following is obtained: Figure 1 After the epitaxial structure shown, the anti-reflection precursor layer 1 is photolithographically preset into a shape. It should be noted that the preset shape can be a circle, annular ring, rectangular, etc., which is determined by the desired electric field of the vertical cavity surface laser emitter, and this application does not make any specific limitation on this.

[0098] Specifically, as a preferred embodiment, the preset shape is a circular ring. After the circular ring is photolithographically formed in the anti-reflection precursor layer 1, the anti-reflection precursor layer 1 material in the circular ring is corroded to the contact layer 2. In practice, the anti-reflection precursor layer 1 material in the circular ring is completely corroded. However, in the actual preparation process of VCSEL, the corrosion depth is not easy to control, so a little more corrosion can be performed, that is, a portion of the contact layer 2 is corroded.

[0099] It should be noted that the contact layer 2 is disposed between the Bragg reflection layer and the antireflection precursor layer 1. The present application does not specifically limit the material, thickness and doping concentration of the contact layer 2. However, in a preferred embodiment, the contact layer 2 is a P-type highly doped GaAs material with a thickness of 5nm-50nm and a doping concentration of 1*10 19 / cm 3 Up to 5*10 19 / cm 3 .

[0100] Furthermore, a conductive material is grown on the side of the anti-reflection precursor layer 1 facing away from the contact layer 2, and then the conductive material outside the preset shape is peeled off, so as to form a first electrode composed of the conductive material in the preset shape. During the peeling, an optional implementation is that after the circular ring is photolithographically formed, a layer of photoresist film is attached to the surface of the epitaxial structure except for other areas within the circular ring, and thus a conductive material is grown on the photoresist film, that is, a conductive material is grown on the side of the anti-reflection precursor layer 1 facing away from the contact layer 2. The present application does not limit the conductive material, but titanium is preferably used. Specifically, titanium can be grown using an electron beam evaporation process to form a dense contact protection.

[0101] In some optional embodiments, in order to avoid that the photoresist film generated after photolithography is insufficient to completely cover other areas except the inner ring, photoresist can be applied to other areas except the inner ring. Further, the conductive material on the photoresist is stripped by ultrasound or wet oxidation, and the present application does not specifically limit the stripping method. Taking ultrasonic stripping as an example, specifically, the epitaxial structure in a liquid environment will be washed away under the action of ultrasound, and the photoresist with weak adhesion and the titanium on it will be retained on the epitaxial structure. The first electrode 40 is formed by titanium in a preset shape, wherein, as an optional embodiment, the first electrode 40 is a P electrode.

[0102] When stripping the conductive material outside the preset shape, another optional implementation is, after growing the conductive material on the side of the anti-reflective precursor layer facing away from the contact layer, applying photoresist on the preset shape, that is, forming a mask on the preset shape, and then etching away the conductive material outside the preset shape, thereby forming a first electrode composed of the conductive material within the preset shape.

[0103] After obtaining the first electrode, the laser table is etched at the edge of the epitaxial structure using the induction induced plasma technology with online monitoring. Specifically, the lithography is performed from the top layer to the lower DBR 6. The table on the lower DBR 6 layer that contacts the air is the laser table.

[0104] Figure 4 A schematic diagram of another epitaxial structure provided in an embodiment of the present application is shown in FIG. Figure 4 As shown in the material placement direction, starting from the anti-reflection precursor layer 1, photolithography is performed along the direction from the anti-reflection precursor layer 1 to the substrate 7 layer, and photolithography is performed to the lower DBR 6 layer. Then, a laser table can be formed on the lower DBR 6 layer, that is, the surface of the lower DBR 6 layer facing away from the substrate 7 and in contact with the air is the laser table.

[0105] As a preferred embodiment, based on the above embodiment, after placing the epitaxial structure in an oxidizing gas environment, oxidizing the antireflection precursor layer to form an antireflection film, and oxidizing a portion of the limiting precursor layer to form an oxidized limiting layer, the method further comprises:

[0106] growing an insulating layer on the laser table;

[0107] Etching an electrode window on the insulating layer;

[0108] growing a conductive material on a side of the insulating layer facing away from the laser mesa;

[0109] Stripping or corroding the conductive material outside the electrode window so that the conductive material in the electrode window constitutes a current carrier of the first electrode;

[0110] A conductive material is grown on a side of the substrate facing away from the Bragg reflection layer to obtain a second electrode.

[0111] In a specific embodiment, Figure 4 As shown, an insulating layer is grown on the laser table along the direction from the substrate 7 to the anti-reflection limiting layer, that is, starting from the lower DBR 6 layer to the anti-reflection precursor layer 1, and the grown insulating layer is used to etch the electrode window. The material of the insulating layer can be SiO2 or Si3N4, and the thickness can be 200nm-300nm. The material and thickness of the insulating layer are not limited in this application.

[0112] Further, an electrode window is etched on the insulating layer. After the electrode window is etched, in an optional embodiment, a layer of photoresist is attached to the surface of the insulating layer in addition to the electrode window, a conductive material is grown on the surface of the insulating layer, and the conductive material on the mask is stripped off, so that the conductive material in the electrode window constitutes the current carrier of the first electrode. Similarly, in the embodiment of the present application, the conductive material on the photoresist can be stripped off by ultrasonic or wet oxidation, which is not specifically limited in the present application.

[0113] Taking ultrasonic stripping as an example, it can be understood that a layer of photoresist is attached to the surface of the insulating layer in the electrode window. Therefore, during ultrasonic stripping, the conductive material on the photoresist can be stripped off, leaving only the conductive material in the electrode window to constitute the current carrier of the first electrode.

[0114] Similarly, in some optional embodiments, in order to avoid the photoresist film generated after photolithography being insufficient to completely cover other areas except the electrode window, a mask can be applied to other areas except the electrode window. In other optional embodiments, the mask can be a photoresist, which is not limited in the present application.

[0115] After etching the electrode window, when generating the power-carrying carrier, in another optional embodiment, photoresist is applied on the power-carrying carrier, that is, a mask is formed on the power-carrying carrier, and then the conductive material outside the preset shape is etched away, thereby, the conductive material in the power-carrying carrier constitutes the power-carrying carrier of the first electrode.

[0116] It is worth noting that the present application does not limit the thickness of the power carrier of the first electrode, but in practical applications, the power carrier of the P electrode is usually thick gold with a thickness of 1um-3um to improve thermal properties.

[0117] Further, a conductive material is grown on the side of the substrate 7 away from the Bragg reflection layer to obtain a second electrode 8. It is worth noting that when the first electrode 40 is a P electrode, the second electrode 8 is an N electrode. In an optional embodiment, when the second electrode 8 is an N electrode, the substrate 7 is thinned, and the N electrode under the substrate 7 is evaporated and annealed, thereby obtaining a vertical cavity surface emitting laser. It should be noted that the thickness of the thinned substrate 7 can be 130um-150um, which ensures the intensity of the laser and is conducive to heat dissipation.

[0118] In addition, it should be noted that the material of the substrate 7 can be GaAs or InP, and the N electrode can be obtained by electron beam evaporation of AuGeNi / Au alloy, and the thickness can be 100nm-500nm.

[0119] like Figure 3 As shown, after the above processes of manufacturing the first electrode 40, manufacturing the laser table, wet oxygen oxidation of the antireflection precursor layer 1 and the limiting precursor layer 4 to manufacture the antireflection film 41 and the oxidation aperture 43, growing the insulating layer, etching the window, forming the power carrier of the first electrode 40, thinning the crystal (substrate 7), manufacturing the second electrode 8, etc., the following is obtained. Figure 3 The vertical cavity surface emitting laser structure shown includes, from top to bottom, a first electrode 40 and an antireflection film 41 as a first layer, a contact layer 2 as a second layer, an upper DBR 3 as a third layer, an oxidation restriction layer 42 as a fourth layer (specifically including an oxidized portion of Al2O3 and an oxidized aperture 43 as an unoxidized portion), an active region 5 as a fifth layer, a lower DBR 6 as a sixth layer, a substrate 7 as a seventh layer, and a second electrode 8 as an eighth layer.

[0120] In a preferred embodiment, the thickness of the N electrode is 100nm-500nm, the thickness of the substrate 7 after thinning is 130um-150um, the thickness of the P electrode current carrier is 1um-3um, the thickness of the insulating layer is 200nm-300nm, and the thickness of the contact layer 2 is 5nm-50nm.

[0121] As a preferred embodiment, the components of the oxidizing gas environment include water vapor and a gas that is inert with respect to any component of the epitaxial structure.

[0122] In the wet oxygen oxidation method provided in the present application, there is no specific limitation on the temperature, the mixing ratio of H2 and N2, and the gas pressure. However, in a preferred embodiment, when the material of the anti-reflection precursor layer 1 is a high-aluminum component, and / or the material of the substrate 7 is GaAs or InP, and / or the active area 5 is a multi-quantum well structure such as InGaAs / GaAs, InGaAs / AlGaAs, InGaAs / GaAsP, and / or the limiting precursor layer 4 is a high-aluminum component, and / or the contact layer 2 is characterized in that it is a P-type highly doped GaAs material, a mixed gas of H2 and N2 is selected as a water vapor carrier, and the ratio of H2 to N2 is 5:95. In addition, at a high temperature of 400-470°C and a gas pressure of 10mbar, the anti-reflection precursor layer 1 and the limiting precursor layer 4 are oxidized simultaneously, and then as shown in FIG. Figure 3 As shown, an antireflection film 41 is formed on the top layer, and an oxidation restriction layer 42 is formed in the middle.

[0123] It is worth noting that when the antireflection precursor layer 1 and the limiting precursor layer 4 are oxidized, they can be oxidized simultaneously or in a selected order, which is not limited in this application. Of course, it is preferred to oxidize simultaneously to obtain the antireflection film 41 and the oxidized aperture 43.

[0124] The method for preparing a vertical cavity surface emitting laser provided in the embodiment of the present application simultaneously oxidizes the anti-reflection precursor layer and the limiting precursor layer by wet oxygen oxidation, thereby obtaining a vertical cavity surface emitting laser having both an anti-reflection film and an oxidized aperture. There is no need to prepare the anti-reflection film separately, which simplifies the preparation process of the vertical cavity surface emitting laser and improves the overall performance of the vertical cavity surface emitting laser.

[0125] In a specific embodiment, etching the antireflection precursor material in the predetermined shape to the contact layer includes:

[0126] The anti-reflection precursor material in a preset shape is etched to the contact layer by a material selective etching solution, and then rinsed by plasma etching.

[0127] Specifically, when etching the antireflection precursor material in the preset shape, the etching is performed by combining dry and wet methods, that is, the wet method is to etch the antireflection precursor material in the preset shape to the contact layer 2 by material selective etching liquid, and then use dry plasma etching for washing.

[0128] Figure 5 A schematic diagram of a method for preparing a vertical cavity surface emitting laser provided in an embodiment of the present application is provided. In order to make the technical solution of the present application more clear to those skilled in the art, the following will be combined with Figure 5 The technical solution of the present application is further described in detail as a whole.

[0129] like Figure 1As shown, the epitaxial structure provided by the present application includes: an anti-reflection precursor layer 1, a contact layer 2, an upper Bragg reflection layer, a confinement precursor layer 4, an active region 5, a lower Bragg reflection layer, and a substrate 7. As a preferred embodiment, the anti-reflection precursor layer 1 and the confinement precursor layer 4 are made of high aluminum components.

[0130] like Figure 5 As shown, the specific steps of the method for preparing the vertical cavity surface emitting laser provided in the present application include:

[0131] S50: After obtaining the epitaxial structure, photolithography a preset shape on the anti-reflection precursor layer, wherein the preset shape is determined according to the applied electric field of the vertical cavity surface emitting laser. Figure 1 A preset shape is photoetched on the epitaxial structure, wherein the preset shape is preferably a circular ring.

[0132] S51: After the antireflection precursor material in a preset shape is corroded or etched to the contact layer, a conductive material is grown on the side of the antireflection precursor layer away from the contact layer. Figure 1 As shown, the high aluminum component layer at the top of the ring is etched away to the contact layer 2, and a conductive material is grown on the side of the anti-reflection precursor layer 1 away from the contact layer 2.

[0133] S52: stripping or corroding the conductive material outside the preset shape, so that the conductive material inside the preset shape constitutes the first electrode, and photolithography epitaxial structure to form the laser table. Figure 4 As shown, starting from the anti-reflection precursor layer 1 , photolithography is performed along the direction from the anti-reflection precursor layer 1 to the substrate 7 layer to the lower DBR 6 , and a laser mesa is formed on the lower DBR 6 .

[0134] S53: By wet oxygen oxidation, the anti-reflection precursor layer is oxidized to form an anti-reflection film, and a portion of the limiting precursor layer is oxidized to form an oxidized limiting layer. Specifically, at a high temperature of 400-470°C, a mixed gas of H2 and N2 in a ratio of 5:95 is used as a water vapor carrier, and under a gas pressure of 10 mbar, the high aluminum component layer of the anti-reflection precursor layer 1 and the high aluminum component of the intermediate limiting precursor layer 4 are simultaneously oxidized. The anti-reflection precursor layer 1 is completely oxidized to form an anti-reflection film 41 covering the contact layer 2. Figure 3 As shown, the oxidation of a portion of the high aluminum component of the precursor layer 4 is restricted, and the unoxidized portion surrounded by the oxidized portion is called the oxidation aperture 43 of the laser.

[0135] S54: growing an insulating layer on the laser table along the direction from the substrate 7 to the anti-reflection limiting layer, and etching an electrode window on the insulating layer.

[0136] S55 : growing a conductive material on the side of the insulating layer facing away from the laser mesa, and stripping off the conductive material outside the electrode window, so that the conductive material in the electrode window constitutes a current carrier of the first electrode 40 .

[0137] S56: Wafer thinning, wherein, as a preferred embodiment, the thickness of the substrate 7 after thinning is 130um-150um.

[0138] S57: Grow a conductive material on the side of the substrate 7 away from the Bragg reflection layer to obtain a second electrode 8, and anneal to obtain a vertical cavity surface emitting laser. Specifically, use electron beam evaporation of AuGeNi / Au alloy to obtain an N electrode, and the thickness may be 100nm-500nm.

[0139] In the resulting vertical cavity surface emitting laser structure, the antireflection precursor material on the contact layer 2 is Al2O3 formed by wet oxygen oxidation of a high aluminum component layer. As a preferred embodiment, the optical thickness of the Al2O3 antireflection film 41 is one quarter of the laser wavelength.

[0140] It should be noted that for the limitations on the elements, component ratios, thickness, doping concentration, structure and other properties of each layer of material in the epitaxial structure, please refer to the description of the above embodiments.

[0141] Through the preparation method provided in this application, the following can be obtained: Figure 3 The vertical cavity surface emitting laser structure shown includes, from top to bottom: a first electrode 40 and an antireflection film 41 in the first layer, a contact layer 2 in the second layer, an upper DBR 3 in the third layer, an oxidation restriction layer 42 in the fourth layer (specifically including an oxidized portion of Al2O3 and an oxidized aperture 43 in the unoxidized portion), an active region 5 in the fifth layer, a lower DBR 6 in the sixth layer, a substrate 7 in the seventh layer and a second electrode 8 in the eighth layer.

[0142] It should be noted that the serial numbers of the steps in the embodiments of the present application do not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0143] In the above embodiment, the preparation method of the vertical cavity surface emitting laser is described in detail, and the present application also provides an embodiment corresponding to the vertical cavity surface emitting laser. The vertical cavity surface emitting laser in the embodiment of the present application is obtained by the preparation method of the vertical cavity surface emitting laser in the above embodiment, so the beneficial effects produced by the embodiment of the present application are the same as those of the above embodiment.

[0144] It is worth noting that the limitations on the materials of each layer mentioned in the above method embodiment are also applicable to this embodiment.

[0145] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0146] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0147] In the embodiments provided in the present application, it should be understood that the disclosed devices / network equipment and methods can be implemented in other ways. For example, the device / network equipment embodiments described above are merely schematic. For example, the division of the modules or units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0148] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0149] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A method for preparing a vertical cavity surface emitting laser, characterized in that: The method comprises the following steps for preparing an oxidation limiting layer and an anti-reflection film of a laser: The epitaxial structure is placed in an oxidizing gas environment, the antireflection precursor layer is oxidized to form the antireflection film, and a portion of the limiting precursor layer is oxidized to form the oxidized limiting layer, wherein the oxidized limiting layer is used to constrain current and / or limit light field.

2. The method for preparing a vertical cavity surface emitting laser according to claim 1, characterized in that: The anti-reflection precursor layer is prepared based on a first preset material, wherein the first preset material includes an aluminum element whose proportion exceeds a preset first threshold, and the first preset material also includes at least one of a gallium element, an indium element, and an arsenic element.

3. The method for preparing a vertical cavity surface emitting laser according to claim 2, characterized in that: The first preset material is unintentionally doped AlGaAs.

4. The method for preparing a vertical cavity surface emitting laser according to claim 1, characterized in that: The epitaxial structure comprises a substrate, a Bragg reflection layer and the anti-reflection precursor layer which are arranged in sequence, the Bragg reflection layer comprises an upper Bragg reflection layer and a lower Bragg reflection layer, at least one confinement precursor layer is included between the upper Bragg reflection layer and the lower Bragg reflection layer, and an active region is arranged between the lower Bragg reflection layer and the confinement precursor layer; wherein the active region is a multi-quantum well structure, and the central wavelength of the emission spectrum of the quantum well matches the wavelength of the vertical cavity surface emitting laser.

5. The method for preparing a vertical cavity surface emitting laser according to claim 4, characterized in that: A first matching layer is disposed on a side of the active region adjacent to the confinement precursor layer, and a second matching layer is disposed on a side of the active region adjacent to the lower Bragg reflection layer; The first matching layer and the second matching layer are used to adjust the wavelength of the vertical cavity surface emitting laser.

6. The method for preparing a vertical cavity surface emitting laser according to claim 4, characterized in that: The Bragg reflection layer includes a plurality of reflection layer pairs, the doping concentrations of the two reflection layer pairs adjacent to the active region are lower than the doping concentrations of the other reflection layer pairs, the refractive indexes of the first reflection layer and the second reflection layer in the reflection layer pair are different, and the reflectivity of the upper Bragg reflection layer and the lower Bragg reflection layer are different.

7. The method for preparing a vertical cavity surface emitting laser according to claim 6, characterized in that: The first reflective layer is prepared based on a second preset material, and the second reflective layer is prepared based on a third preset material, and the second preset material and the third preset material both include aluminum and gallium elements, the aluminum element ratio of the second preset material is greater than the aluminum element ratio of the third preset material, and the gallium element ratio of the second preset material is less than the gallium element ratio of the third preset material.

8. The method for preparing a vertical cavity surface emitting laser according to claim 4, characterized in that: The epitaxial structure further includes a contact layer, which is disposed between the upper Bragg reflector layer and the antireflection precursor layer. Before placing the epitaxial structure in an oxidizing gas environment, oxidizing the antireflection precursor layer to form the antireflection film, and oxidizing a portion of the restriction precursor layer to form the oxidized restriction layer, the method further includes: Acquiring the epitaxial structure; Photolithography a preset shape on the anti-reflection precursor layer; wherein the preset shape is determined according to the applied electric field of the vertical cavity surface emitting laser; Corroding or etching the antireflection precursor material in the preset shape to the contact layer; growing a conductive material on a side of the antireflection precursor layer away from the contact layer; Stripping or corroding the conductive material outside the preset shape so as to form a first electrode composed of the conductive material within the preset shape; The epitaxial structure is photolithographically formed into a laser mesa.

9. The method for preparing a vertical cavity surface emitting laser according to claim 8, characterized in that: After placing the epitaxial structure in an oxidizing gas environment, oxidizing the antireflection precursor layer to form the antireflection film, and oxidizing a portion of the limiting precursor layer to form the oxidized limiting layer, the method further comprises: growing an insulating layer on the laser mesa; Etching an electrode window on the insulating layer; growing the conductive material on a side of the insulating layer facing away from the laser mesa; Stripping or corroding the conductive material outside the electrode window, so that the conductive material in the electrode window constitutes a current carrier of the first electrode, and the current carrier is electrically connected to the first electrode; A conductive material is grown on a side of the substrate facing away from the Bragg reflection layer to obtain a second electrode.

10. A vertical cavity surface emitting laser, characterized in that: The method for preparing a vertical cavity surface emitting laser is used to obtain the vertical cavity surface emitting laser.

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