Vertical cavity surface emitting laser and method for manufacturing the same

Abstract

This invention provides a vertical-cavity surface-emitting laser (VCSEL) and its fabrication method. The fabrication method includes: transferring a connecting layer onto a first substrate or fabricating a connecting layer on the first substrate, wherein the connecting layer is at least one layer, each layer being a layered two-dimensional material with a thickness of one atom or one molecule, and the atoms between the connecting layers are bonded by van der Waals forces, and / or the atoms between the connecting layer and the first substrate are bonded by van der Waals forces. A laser body portion is epitaxially grown on the connecting layer, and the atoms between the connecting layer and the laser body portion are bonded by van der Waals forces. The connecting layer is mechanically peeled off, transferring the connecting layer carrying the laser body portion onto a second substrate covered with a first reflector. By adding a connecting layer, the laser body portion can be easily mechanically peeled off from the first substrate. Compared to traditional laser peeling, this simplifies the process, reduces the production cost of the laser device, and facilitates transfer, expanding the applications of nitride optoelectronic devices.

Description

Technical Field

[0001] This invention relates to the fields of semiconductor lasers and graphene technology, and in particular to a vertical cavity surface-emitting laser and its fabrication method. Background Technology

[0002] Since the 1990s, a global surge of research has been undertaken into GaN-based materials and devices. This research has expanded the wavelength range of semiconductor lasers and holds broad market potential in fields such as high-density optical disc storage, laser displays, and biomedical applications. Vertical-cavity surface-emitting lasers (VCSELs) possess advantages such as small far-field divergence angles, near-circular spot sizes, large aperture operation, and two-dimensional arrangement. Furthermore, they are easily achievable with high power, high data rates, and high-speed response, making them highly promising for applications in optical interconnects, optical communications, optical signal processing, fiber optic communications, neural networks, optical interconnects and free-space optical interconnects in computer chips, and real-time optical signal and graphics processing. The device performance of VCSELs is closely related to material quality. Currently, the most common method for fabricating GaN-based VCSELs involves epitaxially growing a laser structure within a distributed Bragg mirror on a sapphire substrate, followed by complex processes such as laser lift-off and bonding. Summary of the Invention

[0003] (a) Technical problems to be solved

[0004] To address the existing technical problems, this invention provides a vertical cavity surface-emitting laser and its fabrication method, which at least partially solves the above-mentioned technical problems.

[0005] (II) Technical Solution

[0006] This invention provides a method for fabricating a vertical-cavity surface-emitting laser, comprising: transferring a connecting layer 02 onto a first substrate 01 or fabricating a connecting layer 02 on the first substrate 01, wherein the connecting layer 02 is at least one layer and each layer is a layered two-dimensional material with a thickness of a single atom or a single molecule, the interlayer atoms of the connecting layer 02 are bonded by van der Waals forces, and / or the atoms of the connecting layer 02 and the first substrate 01 are bonded by van der Waals forces; epitaxially bonding a laser body portion 08 onto the connecting layer 02, the atoms of the connecting layer 02 and the laser body portion 08 are bonded by van der Waals forces; mechanically peeling off the connecting layer 02, and transferring the connecting layer 02 carrying the laser body portion 08 onto a second substrate 12 covered by a first reflector 11.

[0007] Optionally, before transferring the connecting layer 02 onto the first substrate 01, the method further includes: preparing a graphene layer as the connecting layer 02.

[0008] Optionally, the preparation of graphene layers includes: preparing single-layer graphene or 2-15 layers of multilayer graphene.

[0009] Optionally, before transferring the interconnecting layer 02 onto the first substrate 01, the method further includes growing a 1-5 μm undoped GaN layer on a homogeneous substrate, a sapphire substrate, or an amorphous substrate to obtain the first substrate 01.

[0010] Optionally, the fabrication method of the vertical-cavity surface-emitting laser further includes: fabricating an ion-implanted high-resistivity region 13 or a dielectric thin-film current-blocking layer 17 in the p-electrode region of the laser body 08; fabricating a transparent conductive layer 09 on the laser body 08, and fabricating a second reflector 10 on the transparent conductive layer 09, wherein the reflectivity of the second reflector 10 is less than that of the first reflector 11; etching the transparent conductive layer 09 in the p-electrode region and the n-type doped GaN electron-implanted layer 03 in the n-electrode region of the laser body 08, respectively, to obtain p-electrode patterns and n-electrode patterns; fabricating a first metal electrode 14 and a second metal electrode 15 on the n-electrode patterns and p-electrode patterns, respectively, by electron beam evaporation or sputtering; depositing a passivation layer on the surface and removing part of the passivation layer by photolithography etching to obtain a passivation layer 16, exposing the second reflector 10, the first metal electrode 14, and the second metal electrode 15.

[0011] Optionally, the first reflector 11 and the second reflector 10 can be grown or deposited alternately using materials with different refractive indices.

[0012] Optionally, before transferring the connecting layer 02 carrying the laser body portion 08 onto the second substrate 12 covered by the first reflector 11, the method further includes: fabricating the second substrate 12 using any one of a Si layer, a SiC layer, or an AlN layer.

[0013] Optionally, the laser body 08 epitaxially grown on the connecting layer 02 includes: sequentially epitaxially growing an n-type doped GaN electron injection layer 03, a multi-quantum-well emitting layer 04, a p-type doped AlGaN electron blocking layer 05, a p-type doped GaN hole injection layer 06, and a heavily doped p-type GaN ohmic contact layer 07 on the connecting layer 02, wherein the multi-quantum-well emitting layer 04 is Al X Ga 1-X N / GaN or In Y Ga 1-Y N / GaN quantum well light-emitting layer, 0 < X ​​< 1, 0 < Y < 1.

[0014] Optionally, fabricating the first metal electrode 14 and the second metal electrode 15 on the n-electrode pattern and the p-electrode pattern respectively includes: fabricating the first metal electrode 14 and the second metal electrode 15 using one of Au, Ag, Cu, Pt, Cr, Ni, Al, Ti or any combination thereof; depositing a passivation layer on the surface and removing part of the passivation layer by photolithography etching to obtain a passivation layer 16 includes: depositing a passivation layer 16 using one or a mixture of silicon oxide, silicon nitride or aluminum oxide dielectric films.

[0015] Another aspect of the present invention provides a vertical cavity surface-emitting laser, comprising: a second substrate 12, a first reflector 11, a connecting layer 02, a laser body portion 08, a transparent conductive layer 09, and a second reflector 10 stacked sequentially; wherein the connecting layer 02 is at least one layer and each layer is a layered two-dimensional material with a thickness of a single atom or a single molecule, the interlayer atoms of the connecting layer 02 are bonded by van der Waals forces, and / or the atoms of the connecting layer 02 are bonded to the first reflector 11 and the laser body portion 08 by van der Waals forces; the reflectivity of the second reflector 10 is less than the reflectivity of the first reflector 11.

[0016] (III) Beneficial Effects

[0017] This invention provides a method for fabricating a vertical cavity surface-emitting laser. By adding one or more layers of layered material with a thickness of one atom or one molecule, in which the atoms are bonded by covalent bonds between the laser body and the first substrate, the laser body can be easily mechanically peeled off from the first substrate. Compared with the traditional laser peeling method, this greatly simplifies the process, reduces the production cost of laser devices, and makes them easier to transfer, thus expanding the application of nitride optoelectronic devices.

[0018] Graphene is a layered material with a thickness of one atom or one molecule. The atoms within each layer are bonded by covalent bonds, while the layers are held together by weak van der Waals forces. This two-dimensional material facilitates interlayer separation due to the weak interlayer bonding, enabling the peeling and transfer of devices. The selection of material type and thickness fully considers both device cost and application performance, resulting in outstanding cost-effectiveness. Attached Figure Description

[0019] Figure 1 A flowchart illustrating a method for fabricating a vertical-cavity surface-emitting laser according to an embodiment of the present invention is shown.

[0020] Figure 2 A flowchart illustrating a method for fabricating a vertical-cavity surface-emitting laser according to another embodiment of the present invention is shown.

[0021] Figure 3 A flowchart illustrating a method for fabricating a vertical-cavity surface-emitting laser according to yet another embodiment of the present invention is shown.

[0022] Figure 4 This schematically illustrates the structure of the epitaxial wafer peeling of a vertical cavity surface-emitting laser according to an embodiment of the present invention;

[0023] Figure 5 This schematically illustrates a structural diagram of the fabrication of the second reflector in a vertical cavity surface-emitting laser according to an embodiment of the present invention;

[0024] Figure 6 This schematically illustrates a structural diagram of the fabrication of the second reflector in a vertical-cavity surface-emitting laser according to another embodiment of the present invention;

[0025] Figure 7 This schematically illustrates a mesa structure etched by a vertical cavity surface-emitting laser according to an embodiment of the present invention.

[0026] Figure 8 This schematically illustrates a mesa structure etched by a vertical cavity surface-emitting laser according to another embodiment of the present invention;

[0027] Figure 9 A schematic diagram of a vertical cavity surface-emitting laser according to an embodiment of the present invention is shown.

[0028] Figure 10 A schematic diagram of a vertical cavity surface-emitting laser according to another embodiment of the present invention is shown.

[0029] [Explanation of Labels in the Attached Image]

[0030] 01-First substrate

[0031] 02-Connection Layer

[0032] 03-n type doped GaN electron injection layer

[0033] 04-Multiple quantum well light-emitting layer

[0034] 05-p type doped AlGaN electron blocking layer

[0035] 06-p type doped GaN hole injection layer

[0036] 07-Heavily Doped p-type GaN Ohmic Contact Layer

[0037] 08-Main body of the laser

[0038] 09-Transparent Conductive Layer

[0039] 10-Second reflecting mirror

[0040] 11-First reflecting mirror

[0041] 12-Second substrate

[0042] 13-High Resistance Region

[0043] 14-First Metal Electrode

[0044] 15-Second metal electrode

[0045] 16-Passivation layer

[0046] 17-Dielectric thin film current blocking layer Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0048] Figure 1 A flowchart illustrating the fabrication method of a vertical cavity surface-emitting laser according to an embodiment of the present invention is shown.

[0049] According to embodiments of the present invention, such as Figure 1 As shown, the fabrication method of a vertical-cavity surface-emitting laser includes, for example:

[0050] S101, the connecting layer 02 is transferred to the first substrate 01 or the connecting layer 02 is prepared on the first substrate 01, wherein the connecting layer 02 is at least one layer and each layer is a layered two-dimensional material with a single atom or a single molecule thickness, the interlayer atoms of the connecting layer 02 are bonded by van der Waals forces, and / or the atoms of the connecting layer 02 and the first substrate 01 are bonded by van der Waals forces.

[0051] According to an embodiment of the present invention, before transferring the connecting layer 02 onto the first substrate 01, the method for fabricating a vertical-cavity surface-emitting laser further includes, for example, fabricating a graphene layer as the connecting layer 02. The fabrication of the graphene layer includes, for example, fabricating a single layer of graphene or 2-15 layers of multilayer graphene. When fabricating a single layer of graphene, the graphene layer is bonded to the first substrate 01 by van der Waals forces; when fabricating multilayer graphene, the graphene layers are bonded to each other, and the graphene layers are bonded to the first substrate 01, by van der Waals forces.

[0052] According to an embodiment of the present invention, before transferring the connecting layer 02 onto the first substrate 01, the method for fabricating a vertical cavity surface-emitting laser further includes, for example, growing a 1-5 μm undoped GaN layer on a substrate capable of van der Waals epitaxy of high-quality nitride material, such as a homogeneous substrate, a sapphire substrate, or an amorphous substrate, to obtain the first substrate 01. For example, a 3 μm undoped GaN layer is grown on a sapphire substrate.

[0053] According to embodiments of the present invention, for example, a graphene layer can be grown first and then transferred to an undoped GaN substrate, or the graphene layer can be grown directly on an undoped GaN substrate.

[0054] S102, the main body of the laser 08 is epitaxially grown on the connecting layer 02, and the atoms of the connecting layer 02 and the main body of the laser 08 are bonded together by van der Waals forces.

[0055] According to an embodiment of the present invention, for example, a metal-organic chemical vapor deposition method is used to epitaxially grow the laser body portion 08 on the connecting layer 02. The epitaxial growth method includes, for example, sequentially epitaxially growing an n-type doped GaN electron injection layer 03, a multi-quantum-well emitting layer 04, a p-type doped AlGaN electron blocking layer 05, a p-type doped GaN hole injection layer 06, and a heavily doped p-type GaN ohmic contact layer 07 on the connecting layer 02, wherein the multi-quantum-well emitting layer 04 is Al X Ga 1-X N / GaN or In Y Ga 1-Y N / GaN quantum well light-emitting layer, 0 < X ​​< 1, 0 < Y < 1.

[0056] According to an embodiment of the present invention, the method for fabricating a vertical-cavity surface-emitting laser further includes, for example, performing ion implantation in the P-electrode region of the laser body portion 08, such as implanting boron ions but not limited to implanting boron ions, to fabricate a high-resistivity region 13, or fabricating a dielectric thin-film current-blocking layer 17 in the P-electrode region of the laser body portion 08, wherein the dielectric thin-film current-blocking layer 17 may be, but is not limited to, a silicon oxide layer, to restrict current injection in this region; fabricating a transparent conductive layer 09 on the laser body portion 08, and fabricating a second reflector 10 on the transparent conductive layer 09, wherein the second reflector... The reflectivity of the mirror 10 is less than that of the first mirror 11. The transparent conductive layer 09 in the p-electrode region and the n-type doped GaN electron injection layer 03 in the n-electrode region of the laser body 08 are etched to obtain the p-electrode pattern and the n-electrode pattern, respectively. The first metal electrode 14 and the second metal electrode 15 are fabricated on the n-electrode pattern and the p-electrode pattern, respectively, by electron beam evaporation or sputtering. A passivation layer is deposited on the surface and part of the passivation layer is removed by photolithography and etching to obtain the passivation layer 16, exposing the second mirror 10, the first metal electrode 14 and the second metal electrode 15.

[0057] According to an embodiment of the present invention, a second reflector 10 is fabricated on a transparent conductive layer 09. For example, 12 pairs of SiO2 / Ta2O5 distributed Bragg mirrors can be used, but are not limited to 12 pairs of SiO2 / Ta2O5, to fabricate the second reflector 10.

[0058] In some embodiments of the present invention, for example, a top-layer distributed Bragg reflector may be fabricated first, with the p-electrode connected to the metal oxide transparent conductive layer; the n-electrode region may be etched to expose the n-type doped GaN electron injection layer 03, thereby connecting the n-electrode to the n-type doped GaN electron injection layer 03.

[0059] According to embodiments of the present invention, for example, electron beam evaporation or sputtering methods are used to fabricate a first metal electrode 14 and a second metal electrode 15 on an n-electrode pattern and a p-electrode pattern, respectively. This includes, for example, using one or any combination of metals commonly used in semiconductor processes such as Au, Ag, Cu, Pt, Cr, Ni, Al, and Ti to fabricate the first metal electrode 14 and the second metal electrode 15. The first metal electrode 14 and the second metal electrode 15 can be, but are not limited to, film systems such as Cr, Al, Ti, and Au. A passivation layer is deposited on the surface, and a portion of the passivation layer is removed by photolithography etching to obtain a passivation layer 16. This includes depositing a passivation layer 16 using one or a mixture of dielectric films such as silicon oxide, silicon nitride, or aluminum oxide. The passivation layer 16 can be, but is not limited to, a SiO2 passivation layer.

[0060] S103, mechanically peel off the connecting layer 02 and transfer the connecting layer 02 carrying the main body of the laser 08 to the second substrate 12 covered by the first reflector 11.

[0061] According to an embodiment of the present invention, the laser body 08 is peeled off and transferred by using the connecting layer 02, such as graphene, and the van der Waals forces between the layers to achieve mechanical peeling of the undoped GaN substrate from the laser body 08, and then the laser body 08 is moved to a second substrate 12, such as Si, SiC, AlN, etc., which is covered with a high reflectivity distributed Bragg mirror, thereby realizing the fabrication of a vertical cavity surface emission laser on an arbitrary substrate.

[0062] According to an embodiment of the present invention, the laser body portion 08 is peeled off using tape or adhesive and then transferred onto a second substrate 12 covered with a distributed Bragg reflector.

[0063] According to embodiments of the present invention, for example, the first reflector 11 and the second reflector 10 can be grown or deposited alternately using materials with different refractive indices. The top / bottom layer distributed Bragg reflector of this embodiment is, for example, an epitaxial or dielectric distributed Bragg reflector grown or deposited alternately using materials with different refractive indices. For example, 15 pairs of SiO2 / Ta2O5 distributed Bragg reflectors can be grown on the second substrate 12, but are not limited to 15 pairs of SiO2 / Ta2O5.

[0064] According to an embodiment of the present invention, before transferring the connecting layer 02 carrying the laser body portion 08 onto the second substrate 12 covering the first reflector 11, the method for fabricating a vertical cavity surface-emitting laser further includes, for example, fabricating the second substrate 12 using any one of a Si layer, a SiC layer, or an AlN layer. The second substrate 12 may be a Si substrate, but is not limited to a Si substrate.

[0065] Figure 2 The schematic diagram illustrates a method for fabricating a vertical cavity surface-emitting laser according to another embodiment of the present invention.

[0066] According to embodiments of the present invention, such as Figure 2 As shown, another embodiment of the present invention includes, for example, the method for fabricating a vertical-cavity surface-emitting laser:

[0067] S201: Growing an undoped GaN layer on a sapphire substrate.

[0068] According to an embodiment of the present invention, the undoped GaN substrate is a 3μm undoped GaN layer directly epitaxially grown on a sapphire substrate.

[0069] S202: A single-layer graphene film is coated on an undoped GaN substrate, for example.

[0070] According to embodiments of the present invention, monolayer graphene can be, for example, PMMA spin-coated onto graphene grown by CVD on Cu foil and cured at 110–130°C for 10–18 min. After curing, it is immersed in a 15–30% concentration solution for 3–5 hours. After the Cu foil is completely etched, it is transferred to a clean sapphire substrate, air-dried, and then the PMMA is removed. Alternatively, multilayer graphene can be coated onto an undoped GaN substrate. The preparation of multilayer graphene involves repeating the monolayer preparation steps to obtain multilayer graphene layer by layer.

[0071] S203: The main body of the laser is grown on graphene.

[0072] In some embodiments of the present invention, the epitaxial growth of the main body portion of the vertical cavity surface-emitting laser is performed, for example, by metal-organic chemical vapor deposition.

[0073] According to embodiments of the present invention, the active region of a laser is epitaxially grown using MOCVD. For example, this is achieved by growing a Si-doped GaN electron-injected layer on graphene, followed by the growth of In. 0.11 Ga 0.89 The structure consists of an N / GaN multi-quantum-well light-emitting layer, a p-type doped AlGaN electron blocking layer (05), a p-type doped GaN hole injection layer (06), and finally, a heavily doped p-type GaN ohmic contact layer (07).

[0074] S204: Mechanically strip the main body of the laser and transfer it to a substrate covered with a highly reflective distributed Bragg mirror.

[0075] In some embodiments of the present invention, the laser body portion 08 is peeled off and transferred, for example, by mechanically peeling off the undoped GaN substrate from the laser body portion 08 through the van der Waals forces of graphene, and then transferring the laser body portion 08 to any substrate covered with a high-reflectivity distributed Bragg mirror.

[0076] According to embodiments of the present invention, for example, the adhesive properties of thermally release adhesive tape at room temperature, which disappear upon heating, can be utilized. High-viscosity thermally release adhesive tape can be used to adhere to the active area to be transferred, mechanically peeled off, and transferred to the target location. Then, it can be heated at 90–150°C for 3–10 minutes to remove the thermally release adhesive tape. That is, the main body 08 of the laser can, for example, be peeled off using thermally release adhesive tape and transferred to the second substrate 12 covered with a distributed Bragg reflector, and then heated at 90–150°C for 0.5–5 minutes to remove the thermally release adhesive tape. The method can be, but is not limited to, thermally release adhesive tape.

[0077] S205: Boron is implanted with ions to form a high-resistivity region.

[0078] According to an embodiment of the present invention, boron ions can be injected into the p-electrode region to form a high-resistivity region 13, thereby limiting the injection of current.

[0079] S206: A metal oxide transparent conductive layer is prepared on a heavily doped p-type GaN ohmic contact layer, and the transparent conductive layer in the n region is photolithographically etched.

[0080] According to an embodiment of the present invention, for example, a transparent conductive layer 09 is made by evaporating ITO. Specific experimental conditions may include: evaporating 10-100 nm at 180-240°C, annealing at 300-550°C for 15-45 min in a nitrogen atmosphere, photolithographically etching the n-mesa to cover the p-electrode region with photoresist, exposing the ITO in the n-electrode region, and wet etching the ITO in the n-electrode region.

[0081] S207: Photolithography to create the pattern of the top-layer low-reflectivity distributed Bragg reflector.

[0082] According to an embodiment of the present invention, for example, a top-layer distributed Bragg reflector pattern is lithographically created to expose the p and n electrode regions.

[0083] S208: Plasma etching is used to etch the n-type doped GaN electron injection layer into the n-electrode region to create the n-electrode pattern.

[0084] According to an embodiment of the present invention, for example, a step region of the n-electrode is first defined using photoresist, the photoresist on the step is used as a mask, and then plasma etching is performed until the n-type doped GaN electron injection layer is etched down.

[0085] S209: Prepare p-electrode and n-electrode.

[0086] According to embodiments of the present invention, the metal electrode can generally be prepared by, for example, electron beam evaporation, thermal evaporation, or sputtering of one or any combination of metals commonly used in semiconductor processes such as Au, Ag, Cu, Pt, Cr, Ni, Al, and Ti.

[0087] According to an embodiment of the present invention, for example, Ni / Au is evaporated by electron beam to prepare p-electrodes and n-electrodes on the ITO conductive layer in the p-electrode region and the n-type doped GaN electron-injected layer in the n-electrode region, respectively.

[0088] S210: A layer of SiO2 is deposited on the surface and some of the SiO2 is removed by photolithography to expose the light-emitting region and p and n electrode regions on the distributed Bragg mirror, forming an insulating passivation layer.

[0089] According to an embodiment of the present invention, for example, SiO2 is deposited using plasma-enhanced chemical vapor deposition (PECVD), and the p and n electrodes and the light-emitting region of the laser are lithographically and etched to complete the fabrication of a vertical cavity surface-emitting laser.

[0090] Figure 3 The schematic diagram illustrates a method for fabricating a vertical cavity surface-emitting laser according to another embodiment of the present invention.

[0091] According to embodiments of the present invention, such as Figure 3 As shown, a method for fabricating a vertical-cavity surface-emitting laser according to another embodiment of the present invention includes, for example:

[0092] S301: Undoped GaN layer is grown on a sapphire substrate.

[0093] S302: A single-layer graphene film is coated on an undoped GaN substrate, for example.

[0094] S303: The main body of the laser is grown on graphene.

[0095] S304: Mechanically strip the main body of the laser and transfer it to a substrate covered with a highly reflective distributed Bragg mirror.

[0096] S305: Prepare a dielectric thin film current blocking layer.

[0097] According to an embodiment of the present invention, for example, a dielectric thin film current blocking layer 17 is prepared to restrict the injection of current in this region.

[0098] S306: A metal oxide transparent conductive layer is prepared on a heavily doped p-type GaN ohmic contact layer, and the transparent conductive layer in the n region is photolithographically etched.

[0099] S307: Photolithography to create the pattern of the top-layer low-reflectivity distributed Bragg reflector.

[0100] S308: Plasma etching is used to etch the n-type doped GaN electron-injected layer into the n-electrode region to create the n-electrode pattern.

[0101] S309: Prepare p-electrode and n-electrode.

[0102] S310: A layer of SiO2 is deposited on the surface and some of the SiO2 is removed by photolithography to expose the light-emitting region and p and n electrode regions on the distributed Bragg mirror, forming an insulating passivation layer.

[0103] In summary, this invention provides a method for fabricating a vertical-cavity surface-emitting laser. By adding one or more layers of layered two-dimensional material with a thickness of one atom or one molecule, where atoms are bonded by covalent bonds between the laser body and the first substrate, the laser body can be easily mechanically peeled off from the first substrate. Compared to traditional laser peeling methods, this significantly simplifies the process, reduces the production cost of laser devices, and facilitates transfer, thus expanding the applications of nitride optoelectronic devices.

[0104] Another embodiment of the present invention provides a vertical cavity surface-emitting laser.

[0105] Figure 4 The diagram schematically illustrates the structure of the epitaxial wafer stripping of a vertical cavity surface-emitting laser according to an embodiment of the present invention.

[0106] According to embodiments of the present invention, such as Figure 4 As shown, before transferring the connecting layer 02 carrying the laser body portion 08 onto the second substrate 12 covered by the first reflector 11, the structure for peeling off the vertical cavity surface emission laser epitaxial wafer includes, for example, a first substrate 01, wherein the first substrate 01 includes, for example, an undoped GaN layer on a homogeneous substrate or a sapphire substrate and an amorphous substrate, a connecting layer 02, for example, a graphene layer, and the laser body portion 08.

[0107] Figure 5 The diagram illustrates the structure of a vertical cavity surface-emitting laser (VCSEL) according to an embodiment of the present invention during the fabrication of a second reflector.

[0108] According to an embodiment of the present invention, the second reflector is, for example, a distributed Bragg reflector, and is fabricated on the transparent conductive layer 09 by photolithography, such as... Figure 5As shown, the second reflector includes, for example, a second substrate 12, a first reflector 11, a connecting layer 02, a laser body portion 08, a transparent conductive layer 09, a second reflector 10, and a high-resistivity region 13.

[0109] Figure 6 The diagram schematically illustrates the structure of a second reflector fabricated using a vertical cavity surface-emitting laser according to another embodiment of the present invention.

[0110] According to an embodiment of the present invention, the second reflector is, for example, a distributed Bragg reflector, and is fabricated on the transparent conductive layer 09 by photolithography, such as... Figure 6 As shown, the second reflector includes, for example, a second substrate 12, a first reflector 11, a connection layer 02, a laser body portion 08, a transparent conductive layer 09, a second reflector 10, and a dielectric thin film current blocking layer 17.

[0111] Figure 7 The diagram schematically illustrates the mesa structure etched by a vertical cavity surface-emitting laser according to an embodiment of the present invention.

[0112] According to embodiments of the present invention, such as Figure 7 As shown, the n-electrode region of the vertical-cavity surface-emitting laser in this embodiment of the invention has been etched into the n-type doped GaN electron injection layer 03, for example. The p-electrode region has, for example, a high-resistivity region 13.

[0113] Figure 8 The diagram schematically illustrates a mesa structure etched by a vertical cavity surface-emitting laser according to another embodiment of the present invention.

[0114] According to embodiments of the present invention, such as Figure 8 As shown, the n-electrode region of the vertical-cavity surface-emitting laser in this embodiment of the invention has been etched into the n-type doped GaN electron injection layer 03, for example. The p-electrode region has, for example, a dielectric thin-film current blocking layer 17.

[0115] Figure 9 The diagram schematically illustrates the structure of a vertical cavity surface-emitting laser according to an embodiment of the present invention.

[0116] According to embodiments of the present invention, such as Figure 9As shown, the vertical cavity surface-emitting laser of this embodiment includes, for example, a second substrate 12, a first reflector 11, a connecting layer 02, a laser body portion 08, a transparent conductive layer 09, a second reflector 10, a first metal electrode 14, a second metal electrode 15, and a passivation layer 16, stacked sequentially. The connecting layer 02 is at least one layer, each layer being a layered two-dimensional material with a single atom or single molecule thickness. The atoms between the layers of the connecting layer 02 are bonded by van der Waals forces, and / or the atoms between the connecting layer 02 and the first reflector 11 and the laser body portion 08 are bonded by van der Waals forces. The first reflector 11 and the second reflector 10 are used to form the laser resonant cavity for easy light emission. The reflectivity of the second reflector 10 is less than that of the first reflector 11. The p-electrode region of the laser body portion 08 has a high-resistivity region 13 for limiting current injection in this region. The transparent conductive layer 09 can be, for example, a metal oxide but is not limited to, a metal oxide, and is located between the second reflector 10 and the heavily doped p-type GaN ohmic contact layer 07 to achieve p-side lateral current expansion.

[0117] According to an embodiment of the present invention, the laser body portion 08 includes, for example, an n-type doped GaN electron injection layer 03, a multi-quantum-well emitting layer 04, a p-type doped AlGaN electron blocking layer 05, a p-type doped GaN hole injection layer 06, and a heavily doped p-type GaN ohmic contact layer 07. The n-type doped GaN electron injection layer 03 is used to provide electrons for injection into the active region of the laser. The multi-quantum-well emitting layer 04 is AlGaN. X Ga 1-X N / GaN or In Y Ga 1-Y The N / GaN quantum well light-emitting layer, with 0 < X ​​< 1 and 0 < Y < 1, can be, for example, AlGaN / GaN or InGaN / GaN, suitable for VCSEL structures. The p-type doped AlGaN electron blocking layer (05) reduces electron leakage and provides sufficient holes to allow more carriers to recombine and emit light at the quantum well, increasing the recombination efficiency of electron-hole pairs. The p-type doped GaN hole injection layer (06) provides holes for injection into the laser's active region. The heavily doped p-type GaN ohmic contact layer (07) forms a better ohmic contact with the p-side metal electrode, reducing ohmic contact resistance.

[0118] Figure 10 A schematic diagram of a vertical cavity surface-emitting laser according to another embodiment of the present invention is shown.

[0119] According to embodiments of the present invention, such as Figure 10As shown, the vertical cavity surface-emitting laser of this embodiment includes, for example, a second substrate 12, a first reflector 11, a connecting layer 02, a laser body portion 08, a transparent conductive layer 09, a second reflector 10, a first metal electrode 14, a second metal electrode 15, and a passivation layer 16, stacked sequentially; wherein, the connecting layer 02 is at least one layered material with each layer being a single atom or a single molecule thick, and the interlayer atoms of the connecting layer 02 are bonded by van der Waals forces, and / or the connecting layer 02 is connected to the first reflector 11 and the laser body portion 08. The atoms of 8 are bonded together by van der Waals forces; the first reflector 11 and the second reflector 10 are used to form the laser resonant cavity to facilitate light emission, and the reflectivity of the second reflector 10 is less than that of the first reflector 11; the p electrode region of the laser body 08 has a dielectric thin film current blocking layer 17 for limiting current injection in this region, and the transparent conductive layer 09 can be, for example, a metal oxide but is not limited to a metal oxide, and is located between the second reflector 10 and the heavily doped p-type GaN ohmic contact layer 07 to realize the lateral current expansion on the p side.

[0120] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for fabricating a vertical-cavity surface-emitting laser, characterized in that, include: The connecting layer (02) is transferred to the first substrate (01) or the connecting layer (02) is prepared on the first substrate (01), wherein the connecting layer (02) is at least one layer and each layer is a layered two-dimensional material with a single atom or a single molecule thickness, the interlayer atoms of the connecting layer (02) are bonded by van der Waals forces, and / or the atoms of the connecting layer (02) and the first substrate (01) are bonded by van der Waals forces; The laser body portion (08) is epitaxially grown on the connecting layer (02), and the atoms of the connecting layer (02) and the laser body portion (08) are bonded together by van der Waals forces; Mechanically peel off the connecting layer (02) and transfer the connecting layer (02) carrying the main body part (08) of the laser to the second substrate (12) covered by the first reflector (11); An ion-implanted high-resistivity region (13) or a dielectric thin film current-blocking layer (17) is prepared in the P-electrode region of the main body of the laser (08). A transparent conductive layer (09) is prepared on the main body part (08) of the laser, and a second reflector (10) is prepared on the transparent conductive layer (09), wherein the reflectivity of the second reflector (10) is less than that of the first reflector (11); The transparent conductive layer (09) in the p electrode region and the n-type doped GaN electron injection layer (03) in the n electrode region of the laser body (08) are etched respectively to obtain the p electrode pattern and the n electrode pattern; A first metal electrode (14) and a second metal electrode (15) are fabricated on the n-electrode pattern and the p-electrode pattern, respectively, by electron beam evaporation or sputtering. A passivation layer is deposited on the surface and part of the passivation layer is removed by photolithography and etching to obtain a passivation layer (16), exposing the second reflector (10), the first metal electrode (14) and the second metal electrode (15). The epitaxially grown laser body portion (08) on the connecting layer (02) includes: An n-type doped GaN electron injection layer (03), a multi-quantum well light-emitting layer (04), a p-type doped AlGaN electron blocking layer (05), a p-type doped GaN hole injection layer (06), and a heavily doped p-type GaN ohmic contact layer (07) are epitaxially grown sequentially on the connecting layer (02). The multi-quantum well light-emitting layer (04) is Al... X Ga 1-X N / GaN or In Y Ga 1-Y N / GaN quantum well light-emitting layer, 0 <X<1,0<Y<1。 2. The method for fabricating a vertical-cavity surface-emitting laser according to claim 1, characterized in that, Before transferring the interconnect layer (02) onto the first substrate (01), the method further includes: A graphene layer is prepared as the connecting layer (02).

3. The method for fabricating a vertical-cavity surface-emitting laser according to claim 2, characterized in that, The preparation of the graphene layer includes: Prepare single-layer graphene or 2-15 layer multilayer graphene.

4. The method for fabricating a vertical-cavity surface-emitting laser according to claim 1, characterized in that, Before transferring the interconnect layer (02) onto the first substrate (01), the method further includes: The first substrate (01) is obtained by growing a 1-5 μm undoped GaN layer on a homogeneous substrate, sapphire substrate, or amorphous substrate.

5. The method for fabricating a vertical-cavity surface-emitting laser according to claim 4, characterized in that, The first reflector (11) and the second reflector (10) are grown or deposited alternately using materials with different refractive indices.

6. The method for fabricating a vertical-cavity surface-emitting laser according to claim 1, characterized in that, Before transferring the connecting layer (02) carrying the laser body portion (08) onto the second substrate (12) covered by the first reflector (11), the method further includes: The second substrate (12) is prepared using any one of a Si layer, a SiC layer or an AlN layer.

7. The method for fabricating a vertical-cavity surface-emitting laser according to claim 1, characterized in that, The fabrication of the first metal electrode (14) and the second metal electrode (15) on the n-electrode pattern and the p-electrode pattern, respectively, includes: The first metal electrode (14) and the second metal electrode (15) are prepared using one of Au, Ag, Cu, Pt, Cr, Ni, Al, Ti or any combination thereof. The surface is deposited with a passivation layer and a portion of the passivation layer is removed by photolithography etching to obtain the passivation layer (16), which includes: The passivation layer (16) is obtained by depositing one or a mixture of silicon oxide, silicon nitride or aluminum oxide dielectric films.

8. A vertical-cavity surface-emitting laser prepared by any one of the methods of claims 1-7, characterized in that, include: The second substrate (12), the first reflector (11), the connecting layer (02), the laser body (08), the transparent conductive layer (09), and the second reflector (10) are stacked sequentially. The connecting layer (02) is at least one layer and each layer is a layered two-dimensional material with a thickness of a single atom or a single molecule. The atoms between the layers of the connecting layer (02) are bonded by van der Waals forces, and / or the atoms between the connecting layer (02) and the first reflector (11) and the main body of the laser (08) are bonded by van der Waals forces. The reflectivity of the second mirror (10) is less than that of the first mirror (11).

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