Algan-based semiconductor laser structure and preparation method thereof

Abstract

This invention discloses an AlGaN-based semiconductor laser structure and its fabrication method, relating to the field of semiconductor laser technology. The laser structure includes: a cathode electrode, a substrate layer, a lower confinement layer, a lower waveguide layer, a quantum well active layer, an upper waveguide layer, an upper confinement layer, a ridge waveguide layer, and an anode electrode. The cathode electrode is disposed below the substrate layer, and the anode electrode is disposed above the ridge waveguide layer. The ridge waveguide layer has inclined sidewalls on which ferroelectric material is deposited. Due to the spontaneous polarization and piezoelectric polarization effects of the ferroelectric material and the ridge waveguide layer, a downward polarization electric field is generated, which is beneficial for hole injection. Compared with existing technologies, this invention improves hole injection efficiency, increases hole concentration in the active region, and increases the stimulated recombination rate of the device, thereby improving device performance.

Description

Technical Field

[0001] This invention relates to the field of semiconductor laser technology, and more specifically, to an AlGaN-based semiconductor laser structure and its fabrication method. Background Technology

[0002] Due to the numerous advantages of high-power semiconductor lasers, Fabry-Perot (FP) high-power semiconductor lasers are now widely used in many fields such as manufacturing, laser communication, medical aesthetics, automatic control, and military weaponry. Given the broad application prospects of FP high-power semiconductor lasers, countries around the world are accelerating their high-power semiconductor laser technology research and development programs and establishing high-power semiconductor laser industries, leading to the rapid development of FP semiconductor lasers and related industries.

[0003] Hole injection is a major challenge in the development of high-Al composition semiconductor lasers. Mainstream methods for enhancing hole injection in high-Al composition semiconductor lasers include band engineering, composition-gradient hole injection layers, and metal-insulator-semiconductor (MIS) structures. Currently, mainstream FP semiconductor lasers include blue and green lasers with InGaN / GaN as the active region, deep ultraviolet lasers of the AlGaN series, and red lasers of the GaAs series. Regardless of the material and structure, the goal of lasers is to enhance carrier injection, improve reliability and current injection uniformity, reduce threshold current, and increase device luminous efficiency. Researchers have conducted a series of studies to this end. For example, existing technology discloses a semiconductor laser including a p-type electron blocking layer between the substrate and the active region layer and the p-type cladding layer, and also includes a p-type strained layer (p-type Al). z In 1-z As layer, where z>x), p-type strained layer has large band gap, in p-type electron blocking layer (p-type Al) x In 1-x Between the As layer and the p-type capping layer; in addition, there is a semiconductor laser in which a p-AlGaN polarization-induced layer with a graded Al composition is disposed on the upper and lower surfaces of the upper confinement layer of the semiconductor laser. By inducing p-type doping through double-layer polarization, hole injection is increased, electron leakage is reduced, the carrier recombination efficiency in the active region is improved, and the electrical characteristics of the laser are improved.

[0004] However, since the ionization rate of Mg in the high-Al composition AlGaN layer in the p-region of AlGaN-based deep ultraviolet semiconductor laser is still very low and the hole mobility is small, the hole injection efficiency is poor, which leads to a decrease in the luminous efficiency of the laser. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, such as poor hole injection efficiency affecting the luminous efficiency of FP lasers, this invention provides an AlGaN-based semiconductor laser structure and its fabrication method.

[0006] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0007] In a first aspect, an AlGaN-based semiconductor laser structure includes, along its epitaxial growth direction: a cathode electrode, a substrate layer, a lower confinement layer, a lower waveguide layer, a quantum well active layer, an upper waveguide layer, an upper confinement layer, a ridge waveguide layer, and an anode electrode. The cathode electrode is disposed below the substrate layer, and the anode electrode is disposed above the ridge waveguide layer. The ridge waveguide layer has inclined sidewalls, on which ferroelectric material is deposited. Due to the spontaneous polarization and piezoelectric polarization effects of the ferroelectric material and the ridge waveguide layer, a downward polarization electric field is generated, which is beneficial for hole injection.

[0008] Secondly, a method for fabricating an AlGaN-based semiconductor laser structure includes:

[0009] An epitaxial wafer for an AlGaN-based semiconductor laser is obtained by sequentially growing a lower confinement layer, a lower waveguide layer, a quantum well active region, an upper waveguide layer, an upper confinement layer, and a ridge waveguide layer on an AlGaN substrate using MOCVD (Metal-organic Chemical Vapor Deposition).

[0010] Etch the ridge waveguide layer;

[0011] Sloping sidewalls are further gradient etched onto the ridge waveguide layer after etching.

[0012] Ferroelectric material is deposited on the inclined sidewall;

[0013] An anode electrode is deposited on the upper surface of the ferroelectric material and the ridge waveguide layer, and a cathode electrode is deposited on the lower surface of the substrate layer to obtain the AlGaN-based semiconductor laser structure.

[0014] Compared with the prior art, the beneficial effects of the technical solution of the present invention are:

[0015] This invention discloses an AlGaN-based semiconductor laser structure and its fabrication method. By setting inclined sidewalls in the ridge waveguide layer and depositing ferroelectric material on the inclined sidewalls, the polarization electric field of the ferroelectric material is coupled with the spontaneous polarization and piezoelectric polarization of the ridge waveguide, generating a polarization electric field with the same direction as the electric field generated by the applied voltage. This helps to improve the hole drift velocity, enhance the hole injection efficiency, increase the hole concentration in the active region, increase the stimulated recombination rate of the device, and improve the device performance. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the main cross-sectional structure of the laser structure described in Embodiment 1 of the present invention;

[0017] Figure 2 This is a top view of the laser structure described in Embodiment 1 of the present invention;

[0018] Figure 3 This is a schematic flowchart of the preparation method described in Embodiment 2 of the present invention;

[0019] Figure 4 This is a side view of the epitaxial structure of the AlGaN FP laser described in Embodiment 2 of the present invention;

[0020] Figure 5 This is a schematic diagram of the main view of the epitaxial structure after etching the ridge waveguide layer in Embodiment 2 of the present invention;

[0021] Figure 6 This is a schematic diagram of the main view of the epitaxial structure after gradient etching of the ridge waveguide layer in Embodiment 2 of the present invention;

[0022] Figure 7 This is a schematic diagram of the main structure of the epitaxial structure after secondary epitaxial growth of ferroelectric material in Embodiment 2 of the present invention;

[0023] Figure 8 This is a top view of the epitaxial structure after secondary epitaxial growth of ferroelectric material in Embodiment 2 of the present invention;

[0024] Figure 9 This is a schematic diagram of the main structure of the device after each electrode is formed in Embodiment 2 of the present invention;

[0025] Figure 10 This is a top view of the device structure after the passivation layer is deposited in Embodiment 2 of the present invention;

[0026] The reference numerals in the attached figures are as follows:

[0027] 101—Substrate layer; 102—Lower confinement layer; 103—Lower waveguide layer;

[0028] 104 – Quantum well active layer; 105 – Upper waveguide layer; 106 – Upper confinement layer;

[0029] 107 – Ridge waveguide layer; 108 – Cathode electrode; 109 – Anode electrode;

[0030] 110—Passivation layer; 111—Ferroelectric material; 112—Sloping sidewall;

[0031] 113—Reflective coating; 114—Antireflective coating; 115—Front end face; 116—Rear end face. Detailed Implementation

[0032] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate; this is merely a way of distinguishing objects with the same attributes in the embodiments of this application. In the description of this invention, unless otherwise stated, "a plurality of" means two or more; the terms "center," "longitudinal," "lateral," "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," "tail," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion, such that a process, method, system, product, or apparatus that comprises a series of units is not necessarily limited to those units, but may include other units not expressly listed or inherent to those processes, methods, products, or apparatus.

[0033] The accompanying drawings are for illustrative purposes only and should not be construed as limiting the scope of this patent.

[0034] To better illustrate this embodiment, some parts in the accompanying drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions;

[0035] It will be understood by those skilled in the art that certain well-known structures and their descriptions may be omitted in the accompanying drawings.

[0036] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0037] Example 1

[0038] This embodiment provides an AlGaN-based semiconductor laser structure, see reference. Figure 1 , Figure 2The structure, along its epitaxial growth direction, includes: a cathode electrode 108, a substrate layer 101, a lower confinement layer 102, a lower waveguide layer 103, a quantum well active layer 104, an upper waveguide layer 105, an upper confinement layer 106, a ridge waveguide layer 107, and an anode electrode 109. The cathode electrode 108 is disposed below the substrate layer 101, and the anode electrode 109 is disposed above the ridge waveguide layer 107. The ridge waveguide layer 107 has inclined sidewalls 112, on which ferroelectric material 111 is deposited. Due to the spontaneous polarization and piezoelectric polarization effects of the ferroelectric material 111 and the ridge waveguide layer 107, a downward polarization electric field is generated, which is beneficial for hole injection.

[0039] In this embodiment, by setting an inclined sidewall 112 on the ridge waveguide layer and depositing ferroelectric material 111 on the inclined sidewall 112, the polarization electric field of the ferroelectric material 111 is coupled with the spontaneous polarization and piezoelectric polarization of the ridge waveguide layer 107, generating a polarization electric field with the same direction as the electric field generated by the applied voltage. This helps to increase the hole drift velocity, improve the hole injection efficiency, increase the hole concentration in the active region, increase the stimulated recombination rate of the device, and improve the device performance.

[0040] It should be noted that if ferroelectric material 111 is deposited directly on both sides of the ridge waveguide layer 107, since there is no piezoelectric effect in the lateral direction, the positive polarization electric field will appear directly below the ferroelectric material. This polarization electric field cannot promote hole injection in the middle region of the ridge waveguide. However, in this embodiment, the inclined sidewall 112 is used to deposit ferroelectric material 111. The resulting polarization electric field can concentrate holes in the middle and promote hole injection into the active region.

[0041] In a preferred embodiment, the ferroelectric material 111 comprises κ-Ga2O3 or AlScN, with a thickness of 50 nm-1 μm.

[0042] It should be noted that the thickness of the ferroelectric material 111 is approximately the same as the depth of the inclined sidewall 112.

[0043] In a preferred embodiment, the laser structure further includes a front end face 115 and a rear end face 116, wherein the rear end face 116 is coated with a reflective film 113 and the front end face 115 is coated with an anti-reflection film 114.

[0044] Those skilled in the art will understand that the front end surface 115 and the rear end surface 116 are disposed on two sides of the laser along the laser emission direction, forming a resonant cavity structure.

[0045] In an optional embodiment, the reflective film 113 has a reflectivity of 90%-100%, and the antireflective film 114 has a reflectivity of 90% or less (including 90%).

[0046] It should be noted that when the laser structure is used in a deep ultraviolet laser, a high-reflectivity reflective film and a larger resonant cavity are required to achieve lasing.

[0047] In some examples, the reflectivity of the antireflective coating 114 is less than or equal to 90%.

[0048] In an optional embodiment, the laser structure further includes a passivation layer 110, which covers the upper, lower, left, and right surfaces of the laser, excluding the cathode electrode 108, the anode electrode 109, the front end face 115, and the rear end face 116.

[0049] In a preferred embodiment, the substrate 101 is made of AlGaN and has a thickness of 200nm-3μm.

[0050] In some examples, the thickness of the substrate layer 101 is 200 nm;

[0051] In some examples, the thickness of the substrate layer 101 is 500 nm;

[0052] In some examples, the thickness of the substrate layer 101 is 1 μm;

[0053] In other examples, the thickness of the substrate layer 101 is 2 μm.

[0054] In a preferred embodiment, the lower limiting layer 102 is made of AlGaN and has a thickness of 0.3 μm-1 μm.

[0055] In some examples, the thickness of the lower confinement layer 102 is 0.3 μm;

[0056] In some examples, the thickness of the lower confinement layer 102 is 0.6 μm;

[0057] In some examples, the thickness of the lower confinement layer 102 is 0.9 μm;

[0058] In other examples, the thickness of the lower confinement layer 102 is 1 μm.

[0059] In a preferred embodiment, the lower waveguide layer 103 is made of AlGaN and has a thickness of 0.1μm-3μm.

[0060] In some examples, the thickness of the lower waveguide layer 103 is 0.2 μm;

[0061] In some examples, the thickness of the lower waveguide layer 103 is 0.5 μm;

[0062] In some examples, the thickness of the lower waveguide layer 103 is 0.9 μm;

[0063] In some examples, the thickness of the lower waveguide layer 103 is 1 μm;

[0064] In other examples, the thickness of the lower waveguide layer 103 is 2 μm.

[0065] In a preferred embodiment, the upper waveguide layer 105 is made of AlGaN and has a thickness of 0.1μm-3μm.

[0066] In some examples, the thickness of the upper waveguide layer 105 is 0.2 μm;

[0067] In some examples, the thickness of the upper waveguide layer 105 is 0.6 μm;

[0068] In some examples, the thickness of the upper waveguide layer 105 is 1 μm;

[0069] In other examples, the thickness of the upper waveguide layer 105 is 2 μm.

[0070] In a preferred embodiment, the upper confinement layer 106 is made of AlGaN and has a thickness of 0.3 μm-1 μm.

[0071] In some examples, the thickness of the upper confinement layer 106 is 0.4 μm;

[0072] In some examples, the thickness of the upper confinement layer 106 is 0.6 μm;

[0073] In some examples, the thickness of the upper confinement layer 106 is 0.9 μm;

[0074] In other examples, the thickness of the upper confinement layer 106 is 1 μm.

[0075] In a preferred embodiment, the cathode electrode 108 and / or the anode electrode 109 are made of at least one of Cr / Au, Ti / Au, or Ni / Au.

[0076] In some examples, both the cathode electrode 108 and the anode electrode 109 are made of Cr / Au;

[0077] In other examples, the cathode electrode 108 is made of Cr / Au, and the anode electrode 109 is made of Ti / Au.

[0078] In a preferred embodiment, the quantum well active layer 104 is made of alternating AlGaN well-AlGaN barrier layers with a thickness of 10nm-500nm.

[0079] Those skilled in the art should understand that the thickness of the active layer of a quantum well will vary to some extent depending on the number of cycles of the well barrier.

[0080] In a preferred embodiment, the ridge waveguide layer 107 is made of GaN and has a thickness of 50nm-1μm.

[0081] In some examples, the thickness of the ridge waveguide layer 107 is 50 nm;

[0082] In some examples, the thickness of the ridge waveguide layer 107 is 280 nm;

[0083] In other examples, the thickness of the ridge waveguide layer 107 is 1 μm.

[0084] Example 2

[0085] This embodiment provides a method for fabricating an AlGaN-based semiconductor laser structure. (See attached...) Figure 3 ,include:

[0086] By using MOCVD, a lower confinement layer 102, a lower waveguide layer 103, a quantum well active region 104, an upper waveguide layer 105, an upper confinement layer 106, and a ridge waveguide layer 107 are sequentially epitaxially grown on an AlGaN substrate layer 101 to obtain an epitaxial wafer for an AlGaN-based semiconductor laser.

[0087] Etching the ridge waveguide layer 107;

[0088] Inclined sidewalls 112 are further gradient etched onto the etched ridge waveguide layer 107;

[0089] Ferroelectric material 111 is deposited on the inclined sidewall 112;

[0090] An anode electrode 109 is deposited on the upper surface of the ferroelectric material 111 and the ridge waveguide layer 107, and a cathode electrode 108 is deposited on the lower surface of the substrate layer 101 to obtain the AlGaN-based semiconductor laser structure.

[0091] In this embodiment, the ridge waveguide layer 107 is gradient etched to form an inclined sidewall structure, and ferroelectric material is deposited on the inclined sidewall 112. Due to the coupling effect between the polarization electric field of the ferroelectric material and the spontaneous polarization and piezoelectric polarization of the ridge waveguide, a polarization electric field with the same direction as the electric field generated by the applied voltage is generated, which helps to improve the hole drift velocity, improve the hole injection efficiency, increase the hole concentration in the active region, increase the stimulated recombination rate of the device, and improve the luminous efficiency of the device.

[0092] Furthermore, this embodiment features a simple and reliable process, high repeatability, and low production cost, making it suitable for industrial promotion and applicable to a wide range of laser fields.

[0093] It is important to emphasize that the ridge waveguide layer 107 in this embodiment undergoes a two-step etching process. The initial width of the ridge waveguide layer 107 after MOCVD growth is the same as that of the substrate layer 101 and the upper confinement layer 106. To better confine the light field within the active region and control hole injection to the center of the device, lasers typically employ a ridge-type p-region design. Therefore, the first step involves etching a certain width on both sides of the ridge waveguide layer to prepare the desired ridge structure, forming the final ridge waveguide layer. The second step is gradient etching to form a tilted sidewall structure for secondary epitaxial growth of ferroelectric materials.

[0094] In a preferred embodiment, the method further includes:

[0095] Deposited passivation layer 110;

[0096] A reflective film 113 is deposited on the rear end face 116 of the device, and an anti-reflective film 114 is deposited on the front end face 115 of the device.

[0097] In a preferred embodiment, the depth of the inclined sidewall 112 is 50 nm to 1 μm.

[0098] In one specific implementation, the method includes:

[0099] S1. Place the AlGaN substrate 101 in the growth chamber of the MOCVD equipment, and sequentially grow the lower confinement layer 102, the lower waveguide layer 103, the quantum well active region 104, the upper waveguide layer 105, the upper confinement layer 106, and the ridge waveguide layer 107 to obtain the epitaxial structure of the AlGaN FP laser, as shown below. Figure 4 As shown;

[0100] S2. The ridge waveguide layer 107 is fabricated using photolithography and dry etching processes. The height of the ridge waveguide layer is 50 nm-1 μm. Figure 5 As shown;

[0101] S3. Using photolithography and dry etching processes, inclined sidewalls 112 are gradient-etched on the ridge waveguide layer 107. The depth of the inclined sidewalls 112 is 50nm-1μm. Figure 6 As shown.

[0102] S4. κ-Ga₂O₃ or AlScN of the same thickness as the inclined sidewall 112 is deposited as the ferroelectric material 111 via PECVD (plasma-enhanced chemical vapor deposition) or magnetron sputtering. Figure 7 , Figure 8 As shown;

[0103] S5. The cathode electrode 108 and the anode electrode 109 are fabricated using photolithography and e-beam (electron beam) evaporation processes, such as... Figure 9 As shown;

[0104] S6. A 300 nm thick SiO2 passivation layer 110 is deposited using PECVD, and the SiO2 passivation layer 110 on the surface of the ridge waveguide layer 107 is removed by photolithography and BOE (Buffered Oxide Etch) etchant to form an electrical injection window, such as... Figure 10 As shown;

[0105] S7. A reflective film 113 with a reflectivity of 90%-100% is deposited on the rear end face 116 of the active region of the device using methods such as chemical plating and electroplating, and an antireflection film 114 with a reflectivity of less than or equal to 90% is deposited on the front end face 115 of the device, thus obtaining a laser structure with ferroelectric material deposited on inclined sidewalls, such as... Figure 2 As shown.

[0106] It should be noted that the effect of a laser can be affected by variations in the waveguide layer, confinement layer, active layer materials, processes, and dimensions. Those skilled in the art can make appropriate optimizations based on different device structures and processes to achieve the best effect. This embodiment cannot exhaustively describe all possible implementations.

[0107] It is understood that the method described in this embodiment can prepare the laser structure of Embodiment 1 above, and the options in Embodiment 1 above are also applicable to this embodiment, so they will not be described again here.

[0108] Example 3

[0109] This embodiment proposes an optoelectronic system, including the semiconductor laser structure described in Embodiment 1.

[0110] It is understood that the options in Embodiment 1 above also apply to this embodiment, so they will not be described again here.

[0111] The same or similar labels correspond to the same or similar parts;

[0112] The terms used to describe positional relationships in the accompanying drawings are for illustrative purposes only and should not be construed as limiting this patent.

[0113] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. The functional modules or units can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. An AlGaN-based semiconductor laser structure, characterized in that, The epitaxial growth direction includes: a cathode electrode (108), a substrate layer (101), a lower confinement layer (102), a lower waveguide layer (103), a quantum well active layer (104), an upper waveguide layer (105), an upper confinement layer (106), a ridge waveguide layer (107), and an anode electrode (109). The cathode electrode (108) is disposed below the substrate layer (101), and the anode electrode (109) is disposed above the ridge waveguide layer (107). The ridge waveguide layer (107) is provided with an inclined sidewall (112), and a ferroelectric material (111) is deposited on the inclined sidewall (112). Due to the spontaneous polarization and piezoelectric polarization effect of the ferroelectric material (111) and the ridge waveguide layer (107), a downward polarization electric field is generated, which is beneficial for hole injection.

2. The AlGaN-based semiconductor laser structure according to claim 1, characterized in that, The ferroelectric material (111) includes κ -Ga2O3 or AlScN, with a thickness of 50 nm -1 μm.

3. The AlGaN-based semiconductor laser structure according to claim 1, characterized in that, The laser structure also includes a front end face (115) and a rear end face (116), the rear end face (116) being coated with a reflective film (113) and the front end face (115) being coated with an anti-reflective film (114).

4. The AlGaN-based semiconductor laser structure according to claim 3, characterized in that, The reflective film (113) has a reflectivity of 90%-100%, and the antireflective film (114) has a reflectivity of less than or equal to 90%.

5. The AlGaN-based semiconductor laser structure according to claim 3, characterized in that, It also includes a passivation layer (110) that covers the upper, lower, left, and right surfaces of the laser, excluding the cathode electrode (108), anode electrode (109), front end face (115), and rear end face (116).

6. An AlGaN-based semiconductor laser structure according to claim 5, characterized in that, The passivation layer is made of SiO2 and has a thickness of 50nm-500nm.

7. An AlGaN-based semiconductor laser structure according to any one of claims 1-6, characterized in that, Includes at least one of the following: (1) The substrate layer (101) is made of AlGaN and has a thickness of 200 nm-3 μm; (2) The lower confinement layer (102) is made of AlGaN and has a thickness of 0.3μm-1μm; (3) The lower waveguide layer (103) is made of AlGaN and has a thickness of 0.1 μm - 3 μm; (4) The upper waveguide layer (105) is made of AlGaN and has a thickness of 0.1 μm - 3 μm; (5) The upper confinement layer (106) is made of AlGaN and has a thickness of 0.3μm-1μm; (6) The cathode electrode (108) and / or the anode electrode (109) are made of at least one of Cr / Au, Ti / Au or Ni / Au; (7) The material of the quantum well active layer (104) is an alternating AlGaN well layer-AlGaN barrier layer, and the total thickness of the AlGaN well layer and AlGaN barrier layer is 10nm-500nm. (8) The ridge waveguide layer (107) is made of GaN and has a thickness of 50nm-1μm.

8. A method for fabricating an AlGaN-based semiconductor laser structure, characterized in that, include: By using MOCVD, a lower confinement layer (102), a lower waveguide layer (103), a quantum well active layer (104), an upper waveguide layer (105), an upper confinement layer (106), and a ridge waveguide layer (107) are sequentially epitaxially grown on an AlGaN substrate (101) to obtain an epitaxial wafer for an AlGaN-based semiconductor laser. Etch the ridge waveguide layer (107); Inclined sidewalls (112) are further etched into the ridge waveguide layer (107) after etching. Ferroelectric material (111) is deposited on the inclined sidewall (112). An anode electrode (109) is deposited on the upper surface of the ferroelectric material (111) and the ridge waveguide layer (107), and a cathode electrode (108) is deposited on the lower surface of the substrate layer (101) to obtain the AlGaN-based semiconductor laser structure.

9. The method for fabricating an AlGaN-based semiconductor laser structure according to claim 8, characterized in that, The method further includes: Deposited passivation layer (110); A reflective film (113) is deposited on the rear end face (116) of the device, and an anti-reflective film (114) is deposited on the front end face (115) of the device.

10. The method for fabricating an AlGaN-based semiconductor laser structure according to claim 8, characterized in that, The depth of the inclined sidewall (112) is 50 nm-1 μm.

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