Semiconductor laser and preparation method thereof

Abstract

The invention relates to the technical field of laser, in particular to a semiconductor laser and a preparation method thereof, and the semiconductor laser comprises a P-type electrode layer, a P-type covering layer, a P-type waveguide layer, an active region layer, an N-type waveguide layer, an N-type transition layer, an N-type loss waveguide layer, an N-type covering layer, a substrate layer and an N-type electrode layer which are sequentially stacked from top to bottom. An N-type transition layer and an N-type loss waveguide layer are creatively added below a traditional n-side waveguide, so that ridge-shaped high and low refractive index distribution of the N-type transition layer, the N-type loss waveguide layer and an N-type covering layer is achieved, and then special electric field distribution is achieved. By accurately controlling the material composition, thickness and refractive index distribution of each layer, the energy of the high-order boundary mode can be gradually transferred to the n-side loss waveguide, so that efficient coupling is realized, the n-side waveguide is heavily doped to realize carrier absorption, and the problem caused by the high-order boundary mode can be fundamentally solved.

Description

Technical Field

[0001] This invention belongs to the field of laser technology, and particularly relates to a semiconductor laser and its fabrication method. Background Technology

[0002] Semiconductor lasers, as key components in modern optoelectronics, play an indispensable role in numerous fields such as optical communication, laser processing, medicine, and sensing due to their advantages of small size, high efficiency, and long lifespan. With the continuous improvement of performance requirements for semiconductor lasers in various application areas, such as higher power, better beam quality, and narrower linewidth, effectively optimizing the mode characteristics of semiconductor lasers has become a key research focus and challenge.

[0003] The presence of higher-order boundary modes in the operation of semiconductor lasers can severely impact their performance. These higher-order boundary modes often possess high energy, leading to beam quality degradation during transmission, resulting in issues such as beam distortion and increased divergence angle. This makes it difficult for the laser to maintain good characteristics during long-distance transmission or focusing, thus limiting the application of semiconductor lasers in fields with stringent beam quality requirements, such as precision laser processing and high-resolution imaging. Furthermore, the instability of higher-order boundary modes can cause fluctuations in output power, reducing the reliability and stability of the laser and affecting the normal operation of the system. Currently, although various methods exist for suppressing higher-order boundary modes in semiconductor lasers, they all have certain limitations. For example, some structural design-based methods, such as introducing anti-waveguide mode leakage structures on both sides of the waveguide, can suppress higher-order light modes propagating inside or near the edge of the current injection region to some extent, but they are difficult to effectively suppress higher-order modes bounded by the edge of the semiconductor laser chip, failing to fundamentally solve the problems of power jitter and beam quality degradation. Other methods, such as optimizing material parameters or adjusting manufacturing processes, can improve model characteristics to some extent, but they are often accompanied by increased costs, increased process complexity, and reduced production efficiency, making it difficult to achieve large-scale industrial applications. Summary of the Invention

[0004] In view of this, and in response to the current difficulty in effectively suppressing high-order modes with the edge of the semiconductor laser chip as the boundary, this invention aims to provide a novel semiconductor laser structure that can fundamentally solve the problems caused by high-order boundary modes.

[0005] To achieve the above objectives, the technical solution created by this invention is implemented as follows: This invention provides a semiconductor laser, comprising, from top to bottom, a P-type electrode layer, a P-type capping layer, a P-type waveguide layer, an active region layer, an N-type waveguide layer, an N-type transition layer, an N-type loss waveguide layer, an N-type capping layer, a substrate layer, and an N-type electrode layer; the N-type transition layer, the N-type loss waveguide layer, and the N-type capping layer form a ridge-shaped high and low refractive index distribution; the N-type loss waveguide layer is made of Si-doped AlGaAs material, with a Si-doped AlGaAs weight part of 1 and an Al weight part of 0.2–0.4; the Si doping concentration is 1E19 / cm³. 3 ~1E20 / cm 3 .

[0006] Furthermore, the N-type capping layer is made of Si-doped AlGaAs, with a Si-doped AlGaAs content of 1 part by weight and an Al content of 0.3–0.6 parts by weight; the Si doping concentration is 1E17 / cm³. 3 ~1E19 / cm 3 ; The N-type transition layer is made of Si-doped AlGaAs, with a Si-doped AlGaAs content of 1 part by weight and an Al content of 0.3–0.6 parts by weight; the Si doping concentration is 1E17 / cm³. 3 ~1E18 / cm 3 ; The N-type waveguide layer is made of Si-doped AlGaAs, with a Si-doped AlGaAs weight ratio of 1 and an Al weight ratio of 0.3–0.6; the Si doping concentration is 1E17 / cm³. 3 ~1E18 / cm 3 .

[0007] Furthermore, the thickness of the N-type cladding layer ranges from 0.5 micrometers to 2 micrometers; the thickness of the N-type transition layer ranges from 0.5 micrometers to 1 micrometer; the thickness of the N-type waveguide layer ranges from 0.1 micrometers to 3 micrometers; and the thickness of the N-type loss waveguide layer ranges from 0.5 micrometers to 2 micrometers.

[0008] Furthermore, the active region layer is a barrier / quantum well / barrier structure, and the material of the active region layer is AlGaAs / InGaAs / AlGaAs material, with the weight part of AlGaAs / InGaAs / AlGaAs material being 1, the weight part of In being 0 to 0.5, and the weight part of Al being 0 to 0.5; the weight parts of In and Al are not both 0.

[0009] Furthermore, in the barrier / quantum well / barrier structure, the thickness of the barrier ranges from 1 nanometer to 200 nanometers, and the thickness of the quantum well ranges from 1 nanometer to 20 nanometers; the emission wavelength of the active layer is from 700 nanometers to 1200 nanometers.

[0010] Furthermore, the p-type capping layer is made of C-doped AlGaAs, with a weight ratio of 1 for C-doped AlGaAs and 0.3–0.6 for Al; the C doping concentration is 1E17 / cm³. 3 ~1E19 / cm 3 ; The P-type waveguide layer is made of C-doped AlGaAs, with a weight ratio of 1 for C-doped AlGaAs and 0.3–0.6 for Al; the C doping concentration is 1E16 / cm³. 3 ~1E18 / cm 3 .

[0011] Furthermore, the thickness of the P-type capping layer ranges from 0.1 micrometers to 3 micrometers; the thickness of the P-type waveguide layer ranges from 0.1 micrometers to 10 micrometers.

[0012] Furthermore, the substrate layer is made of GaAs; the thickness of the P-type electrode layer ranges from 200 nm to 500 nm, and the material of the P-type electrode layer is an alloy of at least two of titanium, platinum, gold, nickel, or germanium; the thickness of the N-type electrode layer ranges from 200 nm to 500 nm, and the material of the N-type electrode layer is an alloy of at least two of titanium, platinum, gold, nickel, or germanium.

[0013] This invention provides a method for fabricating the semiconductor laser described above, the method comprising the steps of: S1. An epitaxial structure is fabricated by sequentially depositing an N-type capping layer, an N-type loss waveguide layer, an N-type transition layer, an N-type waveguide layer, an active region layer, a P-type waveguide layer, and a P-type capping layer on a substrate. S2. A ridge waveguide structure is formed on the epitaxial structure by a single photolithography etching process; S3. An insulating material layer is grown on the surface of the P-type capping layer in the epitaxial structure, and a patterned current injection window is formed on the surface of the insulating material layer by photolithography etching; a P-type electrode layer is grown. S4. Thin the substrate layer, grow an N-type electrode layer; anneal, cleave into a chip, and complete the fabrication.

[0014] Furthermore, in step S4, the thickness of the thinned substrate layer ranges from 100 micrometers to 300 micrometers; the insulating material layer is made of SiO2 or Si3N4, and the thickness of the insulating material layer ranges from 50 nanometers to 1000 nanometers.

[0015] Compared with the prior art, the present invention can achieve the following beneficial effects: This invention provides a novel semiconductor laser structure. By creatively adding an N-type transition layer and an N-type loss waveguide layer below the traditional n-side waveguide, the N-type transition layer, N-type loss waveguide layer, and N-type capping layer achieve a ridge-shaped high and low refractive index distribution, thereby realizing a special electric field distribution. By precisely controlling the material composition, thickness, and refractive index distribution of each layer, including the active region layer, waveguide layer, transition layer, and loss waveguide layer, the energy of higher-order boundary modes can be gradually transferred to the n-side loss waveguide, thereby achieving efficient coupling. Furthermore, by redoping the n-side waveguide to achieve carrier absorption, the problems caused by higher-order boundary modes can be fundamentally solved.

[0016] Regarding beam quality improvement, traditional methods struggle to effectively address the issues of beam distortion and increased divergence angle caused by higher-order boundary modes. However, the technical solution provided by this invention enables the beam to become more regular, approaching an ideal Gaussian distribution, significantly reducing the divergence angle, and improving the beam's focusing ability and directionality. In the field of precision laser processing, traditional semiconductor lasers suffer from limitations in improving processing accuracy due to the influence of higher-order modes. In contrast, lasers employing the novel structure provided by this invention can achieve finer processing, such as reaching higher precision requirements in micron-level cutting and engraving. Attached Figure Description

[0017] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic diagram of the two-dimensional cross-sectional structure of a semiconductor laser in a specific embodiment of the present invention; Figure 2 This is a schematic diagram of the refractive index distribution and electric field distribution of the semiconductor laser in the epitaxial direction according to a specific embodiment of the present invention; Figure 3 This is a schematic diagram of the epitaxial boundary mode fundamental mode of a side-emitting semiconductor laser in the prior art. Figure 4 This is a schematic diagram of the first-order mode output of a side-emitting semiconductor laser in the prior art; Figure 5 This is a one-dimensional distribution diagram of the fundamental mode and first-order mode of a side-emitting semiconductor laser along the epitaxial direction in the prior art. Figure 6 This is a diagram showing the substrate distribution after mode coupling is achieved by the semiconductor laser in a specific embodiment of the present invention. Figure 7 This is a diagram showing the first-order mode distribution after mode coupling is achieved using a semiconductor laser in a specific embodiment of the present invention. Figure 8 This is a one-dimensional distribution diagram of the fundamental mode and first-order mode of the semiconductor laser along the epitaxial direction in a specific embodiment of the present invention.

[0018] Explanation of reference numerals in the attached figures: 101. Substrate layer; 102. N-type cladding layer; 103. N-type loss waveguide layer; 104. N-type transition layer; 105. N-type waveguide layer; 106. Active region layer; 107. P-type waveguide layer; 108. P-type cladding layer; 109. Ridge waveguide; 110. Contact material layer; 111. Laser epitaxial direction fundamental mode; 112. Laser epitaxial direction first-order mode; 113. Lateral boundary mode coupled to the N-side loss waveguide. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not constitute a limitation thereof.

[0020] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0021] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing this 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 on this invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0022] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0023] A schematic diagram of the two-dimensional cross-sectional structure of the semiconductor laser provided in the specific embodiments of the present invention is shown below. Figure 1 As shown in the figure, the semiconductor laser includes, from top to bottom, a P-type electrode layer, a P-type capping layer 108, a P-type waveguide layer 107, an active region layer 106, an N-type waveguide layer 105, an N-type transition layer 104, an N-type loss waveguide layer 103, an N-type capping layer 102, a substrate layer 101, and an N-type electrode layer. The N-type transition layer 104, the N-type loss waveguide layer 103, and the N-type capping layer 102 form a ridge-shaped high and low refractive index distribution. Specifically, a ridge waveguide 109 is formed on the P-type capping layer 108, an insulating material layer 110 is grown on the surface of the P-type capping layer 108, and a patterned current injection window is formed on the surface of the insulating material layer 110 by photolithography etching to grow a P-type metal electrode. Compared with traditional structures, the novel semiconductor laser structure provided by the specific embodiments of this invention creatively adds an N-type transition layer and an N-type loss waveguide layer below the traditional n-side waveguide, enabling the N-type transition layer, N-type loss waveguide layer, and N-type capping layer to achieve a ridge-shaped high and low refractive index distribution, thereby achieving a special electric field distribution. By precisely controlling the material composition, thickness, and refractive index distribution of each layer, such as the active region layer, waveguide layer, transition layer, and loss waveguide layer, the energy of higher-order boundary modes can be gradually transferred to the n-side loss waveguide, thereby achieving efficient coupling. Furthermore, by redoping the n-side waveguide to achieve carrier absorption, the problems caused by higher-order boundary modes can be fundamentally solved.

[0024] In a specific embodiment, the N-type loss waveguide layer 103 is made of Si-doped AlGaAs, with a weight ratio of 1 for Si-doped AlGaAs and 0.2-0.4 for Al; the Si doping concentration is 1E19 / cm³. 3 ~1E20 / cm 3The thickness of the N-type loss waveguide layer 103 ranges from 0.5 micrometers to 2 micrometers. In a specific embodiment of the present invention, heavy doping of the n-side loss waveguide is a key step in achieving high-order boundary mode loss. Based on the absorption of photons by charge carriers, the heavily doped n-side loss waveguide can effectively absorb the energy of high-order boundary modes, thereby achieving loss of high-order modes.

[0025] The N-type capping layer 102 is made of Si-doped AlGaAs, with a weight ratio of 1 part Si-doped AlGaAs and a weight ratio of 0.3 to 0.6 parts Al; the Si doping concentration is 1E17 / cm³. 3 ~1E19 / cm 3 The thickness of the N-type capping layer 102 ranges from 0.5 micrometers to 2 micrometers; the material of the N-type transition layer 104 is Si-doped AlGaAs, with a weight ratio of 1 part Si-doped AlGaAs and a weight ratio of 0.3 to 0.6 parts Al; the Si doping concentration is 1E17 / cm³. 3 ~1E18 / cm 3 The thickness of the N-type transition layer 104 ranges from 0.5 micrometers to 1 micrometer; the material of the N-type waveguide layer 105 is Si-doped AlGaAs, with a weight ratio of 1 part Si-doped AlGaAs and a weight ratio of 0.3 to 0.6 parts Al; the Si doping concentration is 1E17 / cm³. 3 ~1E18 / cm 3 The thickness of the N-type waveguide layer 105 ranges from 0.1 micrometers to 3 micrometers.

[0026] In a specific implementation, the active layer 106 is a barrier / quantum well / barrier structure. The material of the active layer is AlGaAs / InGaAs / AlGaAs, with a weight ratio of 1 for AlGaAs / InGaAs / AlGaAs, a weight ratio of 0-0.5 for In, and a weight ratio of 0-0.5 for Al. The weight ratios of In and Al are not simultaneously 0. In the barrier / quantum well / barrier structure, the thickness of the barrier ranges from 1 nm to 200 nm, and the thickness of the quantum well ranges from 1 nm to 20 nm. The emission wavelength of the active layer is 700 nm to 1200 nm.

[0027] In a specific embodiment, the p-type capping layer 108 is made of C-doped AlGaAs material, with a weight ratio of 1 part C-doped AlGaAs material and a weight ratio of 0.3 to 0.6 parts Al; the C doping concentration is 1E17 / cm³. 3 ~1E19 / cm 3The thickness of the P-type capping layer 108 ranges from 0.1 micrometers to 3 micrometers; the material of the P-type waveguide layer 107 is C-doped AlGaAs, with a weight ratio of 1 part C-doped AlGaAs and a weight ratio of 0.3 to 0.6 parts Al; the C doping concentration is 1E16 / cm³. 3 ~1E18 / cm 3 The thickness of the P-type waveguide layer 107 ranges from 0.1 micrometers to 10 micrometers.

[0028] In a specific embodiment, the substrate layer 101 is made of N-type GaAs; the thickness of the P-type electrode layer ranges from 200 nm to 500 nm, and the material of the P-type electrode layer is an alloy material formed from at least two of titanium, platinum, gold, nickel, or germanium; the thickness of the N-type electrode layer ranges from 200 nm to 500 nm, and the material of the N-type electrode layer is an alloy material formed from at least two of titanium, platinum, gold, nickel, or germanium.

[0029] like Figure 2 The diagram shows the epitaxial refractive index distribution and electric field distribution of a semiconductor laser in a specific embodiment of the present invention. The left side shows the refractive index distribution, and the right side shows the electric field distribution. As can be seen from the diagram, the novel semiconductor laser structure provided in this embodiment effectively dissipates the high-order boundary modes of the n-side loss waveguide by coupling the higher-order boundary modes along the epitaxial direction to the n-side loss waveguide, which is located below the conventional side-emitting n-side waveguide, separated by a buffer layer. The n-side loss waveguide is then redoped to achieve carrier absorption, thereby effectively dissipating the higher-order boundary modes of the n-side waveguide. This not only significantly improves the beam quality and stability of the semiconductor laser but also offers advantages such as simple fabrication, low cost, and ease of integration, providing a new approach for improving the performance and widespread application of semiconductor lasers.

[0030] In a specific embodiment of the present invention, the epitaxial structure of the semiconductor laser utilizes precisely controlled material composition, thickness, and refractive index distribution of the active region layer, waveguide layer, loss waveguide layer, and transition layer to form a gradually changing refractive index transition region between the propagation path of the higher-order boundary mode and the n-side loss waveguide. This refractive index transition region acts as a bridge, allowing the energy of the higher-order boundary mode to gradually transfer to the n-side loss waveguide. When the higher-order boundary mode propagates into this transition region, its propagation direction and field distribution change due to the change in refractive index, matching the mode's propagation constant with that of the n-side loss waveguide mode, thus achieving efficient coupling. Specifically, by adjusting the doping concentration of the material in the transition region, its refractive index can be altered, making the wave vector of the higher-order boundary mode and the wave vector of the n-side loss waveguide mode close within a certain range, satisfying the phase-matching condition and promoting coupling between modes.

[0031] like Figure 3 and Figure 4 The figures shown are the distribution diagrams of the fundamental mode and the first-order mode of the boundary mode along the epitaxial direction in conventional semiconductor laser structures in the prior art; as shown... Figure 6 and Figure 7 The figures show the base film distribution and first-order mode distribution of the semiconductor laser with the novel structure provided in the specific embodiment of the present invention after mode coupling. As can be seen from the figures, the base mode is distributed in the waveguide layer, with a high overlap with the active region, while the first-order mode is distributed in the loss waveguide layer. Light cannot pass through the active region to generate gain. This fully demonstrates that by creatively adding an N-type transition layer and an N-type loss waveguide layer below the traditional n-side waveguide, the N-type transition layer, N-type loss waveguide layer, and N-type capping layer achieve a ridge-shaped high and low refractive index distribution, coupling the second-order mode of the traditional structure to the loss waveguide, and redoping the n-side loss waveguide to achieve carrier absorption, thereby achieving loss of higher-order modes.

[0032] like Figure 5 The diagram shown is a one-dimensional distribution of the fundamental mode and first-order mode along the epitaxial direction of a conventional semiconductor laser structure in the prior art; as shown... Figure 8 The figure shows a one-dimensional distribution diagram of the fundamental mode and first-order mode of the semiconductor laser with the novel structure provided in a specific embodiment of the present invention along the epitaxial direction. Comparing the two figures, it can be found that, compared with the existing structure, the present invention increases the stability of the fundamental mode by introducing an N-type loss waveguide layer to distribute the first-order mode in the region without gain, thereby generating high loss.

[0033] In a specific embodiment of the present invention, a method for fabricating the semiconductor laser described above is also provided, the method comprising the steps of: S1. An epitaxial structure is fabricated by sequentially depositing an N-type capping layer 102, an N-type loss waveguide layer 103, an N-type transition layer 104, an N-type waveguide layer 105, an active region layer 106, a P-type waveguide layer 107, and a P-type capping layer 108 on a substrate layer 101. S2. A ridge waveguide 109 structure is formed on the epitaxial structure by a single photolithography etching process; S3. An insulating material layer 110 is grown on the surface of the P-type capping layer 108 in the epitaxial structure, and a patterned current injection window is formed on the surface of the insulating material layer 110 by photolithography etching; a P-type electrode layer is grown; the material of the insulating material layer 110 is SiO2 or Si3N4, and the thickness of the insulating material layer 110 ranges from 50 nanometers to 1000 nanometers. S4. Thin the substrate layer 101 and grow an N-type electrode layer; the thickness of the thinned substrate layer 110 is in the range of 100 micrometers to 300 micrometers; anneal, cleave into a chip, and complete the fabrication of the semiconductor laser.

[0034] In a specific implementation, the method for fabricating a semiconductor laser includes the following steps: Step 1: Design the photolithography pattern for etching to form the ridge waveguide structure and the photolithography pattern for the electrode structure.

[0035] Step 2: On an N-type GaAs substrate, an N-type capping layer, an N-type loss waveguide layer, an N-type transition layer, an N-type waveguide layer, an active region layer, a P-type waveguide layer, and a P-type capping layer are sequentially prepared by epitaxial growth to obtain a wafer containing an epitaxial structure.

[0036] Step 3: Perform a photolithography process and a dry etching process on the photolithography pattern of the ridge waveguide structure on the surface of the grown wafer to prepare the ridge waveguide. Then perform a BOE mask removal process and a cleaning process to obtain a wafer containing the ridge waveguide. Step 4: An insulating material layer is grown on the wafer surface containing the ridge waveguide using a PECVD (plasma-enhanced chemical vapor deposition) device; Step 5: Use the photolithography pattern of the electrode structure to perform a secondary photolithography process, and then use a dry etching process to prepare the electrode implantation structure; Step 6: Grow a P-type metal electrode in a metal film evaporation device to obtain a P-type electrode layer; Step 7: Thin, polish, and clean the N-type substrate, sputter an N-type metal electrode onto the N-type substrate layer to obtain an N-type electrode layer, and perform an annealing process on the wafer to form an ohmic contact; Step 8: Cleave the wafer into bar strips, deposit an anti-reflective film on the back surface, and cleave the bar strips into chips to obtain the semiconductor laser of the present invention.

[0037] The invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0038] Example 1 In this embodiment, the semiconductor laser includes, from top to bottom, a P-type electrode layer, a P-type capping layer, a P-type waveguide layer, an active region layer, an N-type waveguide layer, an N-type transition layer, an N-type loss waveguide layer, an N-type capping layer, a substrate layer, and an N-type electrode layer; wherein, the N-type loss waveguide layer is made of Si-doped AlGaAs material, with a weight ratio of 1 part Si-doped AlGaAs material and 0.3 parts Al by weight; the Si doping concentration is 1E19 / cm³. 3 The thickness is 1 micrometer; the N-type capping layer is made of Si-doped AlGaAs, with a weight ratio of 1 part Si-doped AlGaAs and 0.5 parts Al; the Si doping concentration is 1E19 / cm³. 3 The thickness is 1 micrometer; the N-type transition layer is made of Si-doped AlGaAs, with a weight ratio of 1 part Si-doped AlGaAs and 0.4 parts Al; the Si doping concentration is 1.5E17 / cm³. 3 The thickness is 0.8 micrometers; the N-type waveguide layer is made of Si-doped AlGaAs, with a weight ratio of 1 part Si-doped AlGaAs and 0.5 parts Al; the Si doping concentration is 1.5E17 / cm³. 3 The thickness is 1 micrometer; the active layer is made of AlGaAs / InGaAs / AlGaAs material, with AlGaAs / InGaAs / AlGaAs material accounting for 1% by weight, In accounting for 0.2% by weight, and Al accounting for 0.3% by weight; in this barrier / quantum well / barrier structure, the barrier thickness ranges from 50 nanometers, and the quantum well thickness is 10 nanometers; the p-type capping layer is made of C-doped AlGaAs material, with C-doped AlGaAs material accounting for 1% by weight, and Al accounting for 0.3% by weight; the C doping concentration is 1E17 / cm³. 3 The thickness is 0.1 micrometers; the P-type waveguide layer is made of C-doped AlGaAs, with a weight ratio of 1 part C-doped AlGaAs and 0.6 parts Al; the C doping concentration is 1E18 / cm³. 3 The substrate is an N-type GaAs material with a thickness of 200 micrometers; the insulating material layer grown on the surface of the P-type capping layer is made of SiO2 with a thickness of 500 nanometers; the grown P-type metal electrode is made of an alloy of titanium and platinum with a thickness of 300 nanometers; and the grown N-type metal electrode is made of an alloy of titanium and nickel with a thickness of 400 nanometers.

[0039] Example 2 In this embodiment, the semiconductor laser includes, from top to bottom, a P-type electrode layer, a P-type capping layer, a P-type waveguide layer, an active region layer, an N-type waveguide layer, an N-type transition layer, an N-type loss waveguide layer, an N-type capping layer, a substrate layer, and an N-type electrode layer; wherein, the N-type loss waveguide layer is made of Si-doped AlGaAs material, with a weight ratio of 1 part Si-doped AlGaAs material and 0.2 parts Al by weight; the Si doping concentration is 1.5E20 / cm³. 3 The thickness is 2 micrometers; the N-type capping layer is made of Si-doped AlGaAs, with a weight ratio of 1 part Si-doped AlGaAs and 0.6 parts Al; the Si doping concentration is 1E18 / cm³. 3 The thickness is 0.5 micrometers; the N-type transition layer is made of Si-doped AlGaAs, with a weight ratio of 1 part Si-doped AlGaAs and 0.6 parts Al; the Si doping concentration is 1E17 / cm³. 3 The thickness is 0.5 micrometers; the N-type waveguide layer is made of Si-doped AlGaAs, with a weight ratio of 1 part Si-doped AlGaAs and 0.3 parts Al; the Si doping concentration is 1E17 / cm³. 3 The thickness is 0.5 micrometers; the active layer is made of AlGaAs / InGaAs / AlGaAs material, with AlGaAs / InGaAs / AlGaAs material having a weight ratio of 1, In having a weight ratio of 0, and Al having a weight ratio of 0.5; in this barrier / quantum well / barrier structure, the barrier thickness ranges from 1 nanometer, and the quantum well thickness is 20 nanometers; the p-type capping layer is made of C-doped AlGaAs material, with C-doped AlGaAs material having a weight ratio of 1, and Al having a weight ratio of 0.6; the C doping concentration is 1E18 / cm³. 3 The thickness is 3 micrometers; the P-type waveguide layer is made of C-doped AlGaAs, with a weight ratio of 1 part C-doped AlGaAs and 0.3 parts Al; the C doping concentration is 1E17 / cm³. 3 The substrate is an N-type GaAs material with a thickness of 0.1 micrometers; the insulating material layer grown on the surface of the P-type capping layer is made of Si3N4 with a thickness of 50 nanometers; the grown P-type metal electrode is made of an alloy of nickel and germanium with a thickness of 500 nanometers; and the grown N-type metal electrode is made of an alloy of platinum and nickel with a thickness of 200 nanometers.

[0040] Example 3 In this embodiment, the semiconductor laser includes, from top to bottom, a P-type electrode layer, a P-type capping layer, a P-type waveguide layer, an active region layer, an N-type waveguide layer, an N-type transition layer, an N-type loss waveguide layer, an N-type capping layer, a substrate layer, and an N-type electrode layer; wherein, the N-type loss waveguide layer is made of Si-doped AlGaAs material, with a weight ratio of 1 part Si-doped AlGaAs material and 0.4 parts Al by weight; the Si doping concentration is 1.5E19 / cm³. 3 The thickness is 1.5 micrometers; the N-type capping layer is made of Si-doped AlGaAs, with a weight ratio of 1 part Si-doped AlGaAs and 0.6 parts Al; the Si doping concentration is 1E18 / cm³. 3 The thickness is 1.5 micrometers; the N-type transition layer is made of Si-doped AlGaAs, with a weight ratio of 1 part Si-doped AlGaAs and 0.6 parts Al; the Si doping concentration is 1E18 / cm³. 3 The thickness is 1 micrometer; the N-type waveguide layer is made of Si-doped AlGaAs, with a weight ratio of 1 part Si-doped AlGaAs and 0.6 parts Al; the Si doping concentration is 1E18 / cm³. 3 The thickness is 3 micrometers; the active layer is made of AlGaAs / InGaAs / AlGaAs material, with AlGaAs / InGaAs / AlGaAs material having a weight ratio of 1, In having a weight ratio of 0.5, and Al having a weight ratio of 0; in this barrier / quantum well / barrier structure, the barrier thickness ranges from 100 nanometers, and the quantum well thickness is 1 nanometer; the substrate layer is an N-type GaAs material with a thickness of 100 micrometers; the P-type capping layer is made of C-doped AlGaAs material, with C-doped AlGaAs material having a weight ratio of 1, and Al having a weight ratio of 0.4; the C doping concentration is 1E18 / cm³. 3 The thickness is 2 micrometers; the P-type waveguide layer is made of C-doped AlGaAs, with a weight ratio of 1 part C-doped AlGaAs and 0.5 parts Al; the C doping concentration is 1E16 / cm³. 3 The thickness is 10 micrometers; the insulating material layer grown on the surface of the P-type capping layer is made of SiO2 and has a thickness of 50 nanometers; the grown P-type metal electrode is made of an alloy of titanium and platinum and has a thickness of 300 nanometers; the grown N-type metal electrode is made of an alloy of titanium and nickel and has a thickness of 400 nanometers.

[0041] Example 4 In this embodiment, the semiconductor laser includes, from top to bottom, a P-type electrode layer, a P-type capping layer, a P-type waveguide layer, an active region layer, an N-type waveguide layer, an N-type transition layer, an N-type loss waveguide layer, an N-type capping layer, a substrate layer, and an N-type electrode layer; wherein, the N-type loss waveguide layer is made of Si-doped AlGaAs material, with a weight ratio of 1 part Si-doped AlGaAs material and 0.3 parts Al by weight; the Si doping concentration is 1E19 / cm³. 3 The thickness is 0.5 micrometers; the N-type capping layer is made of Si-doped AlGaAs, with a weight ratio of 1 part Si-doped AlGaAs and 0.4 parts Al; the Si doping concentration is 1E19 / cm³. 3 The thickness is 1.5 micrometers; the N-type transition layer is made of Si-doped AlGaAs, with a weight ratio of 1 part Si-doped AlGaAs and 0.5 parts Al; the Si doping concentration is 1.8E17 / cm³. 3 The thickness is 0.6 micrometers; the N-type waveguide layer is made of Si-doped AlGaAs, with a weight ratio of 1 part Si-doped AlGaAs and 0.4 parts Al; the Si doping concentration is 1.6E17 / cm³. 3 The thickness is 0.1 micrometers; the active layer is made of AlGaAs / InGaAs / AlGaAs material, with AlGaAs / InGaAs / AlGaAs material accounting for 1% by weight, In accounting for 0.4% by weight, and Al accounting for 0.1% by weight; in this barrier / quantum well / barrier structure, the barrier thickness ranges from 150 nanometers, and the quantum well thickness is 5 nanometers; the p-type capping layer is made of C-doped AlGaAs material, with C-doped AlGaAs material accounting for 1% by weight, and Al accounting for 0.5% by weight; the C doping concentration is 1E19 / cm³. 3 The thickness is 3 micrometers; the P-type waveguide layer is made of C-doped AlGaAs, with a weight ratio of 1 part C-doped AlGaAs and 0.4 parts Al; the C doping concentration is 1E17 / cm³. 3 The substrate is an N-type GaAs material with a thickness of 200 micrometers; the insulating material layer grown on the surface of the P-type capping layer is made of SiO2 with a thickness of 100 nanometers; the grown P-type metal electrode is made of an alloy of metallic nickel and metallic platinum with a thickness of 350 nanometers; the grown N-type metal electrode is made of an alloy of metallic nickel and metallic platinum with a thickness of 350 nanometers.

[0042] Example 5 In this embodiment, the semiconductor laser includes, from top to bottom, a P-type electrode layer, a P-type capping layer, a P-type waveguide layer, an active region layer, an N-type waveguide layer, an N-type transition layer, an N-type loss waveguide layer, an N-type capping layer, a substrate layer, and an N-type electrode layer; wherein, the N-type loss waveguide layer is made of Si-doped AlGaAs material, with a weight ratio of 1 part Si-doped AlGaAs material and 0.35 parts Al by weight; the Si doping concentration is 1E20 / cm³. 3 The thickness is 1.2 micrometers; the N-type capping layer is made of Si-doped AlGaAs, with a weight ratio of 1 part Si-doped AlGaAs and 0.4 parts Al; the Si doping concentration is 1E18 / cm³. 3 The thickness is 1.2 micrometers; the N-type transition layer is made of Si-doped AlGaAs, with a weight ratio of 1 part Si-doped AlGaAs and 0.45 parts Al; the Si doping concentration is 1E17 / cm³. 3 The thickness is 0.6 micrometers; the N-type waveguide layer is made of Si-doped AlGaAs, with a weight ratio of 1 part Si-doped AlGaAs and 0.5 parts Al; the Si doping concentration is 1E18 / cm³. 3 The thickness is 3 micrometers; the active layer is made of AlGaAs / InGaAs / AlGaAs material, with AlGaAs / InGaAs / AlGaAs material accounting for 1% by weight, In accounting for 0.1% by weight, and Al accounting for 0.4% by weight; in this barrier / quantum well / barrier structure, the barrier thickness ranges from 150 nanometers, and the quantum well thickness is 15 nanometers; the p-type capping layer is made of C-doped AlGaAs material, with C-doped AlGaAs material accounting for 1% by weight, and Al accounting for 0.5% by weight; the C doping concentration is 1E19 / cm³. 3 The thickness is 0.5 micrometers; the P-type waveguide layer is made of C-doped AlGaAs, with a weight ratio of 1 part C-doped AlGaAs and 0.5 parts Al; the C doping concentration is 1E17 / cm³. 3 The substrate is a 200-micrometer-thick N-type GaAs material; the insulating material layer grown on the surface of the P-type capping layer is made of Si3N4 with a thickness of 500 nanometers; the grown P-type metal electrode is an alloy of gold and platinum with a thickness of 200 nanometers; and the grown N-type metal electrode is an alloy of titanium and germanium with a thickness of 500 nanometers.

[0043] It should be understood that the various forms of processes shown above can be used to reorder, add, or delete steps. For example, the steps described in this invention disclosure can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution disclosed in this invention can be achieved, and this is not limited herein.

[0044] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A semiconductor laser, characterized in that: The semiconductor laser comprises, from top to bottom, a P-type electrode layer, a P-type capping layer, a P-type waveguide layer, an active region layer, an N-type waveguide layer, an N-type transition layer, an N-type loss waveguide layer, an N-type capping layer, a substrate layer, and an N-type electrode layer. The N-type transition layer, the N-type loss waveguide layer, and the N-type capping layer form a ridge-shaped high and low refractive index distribution; The N-type loss waveguide layer is made of Si-doped AlGaAs, with a weight ratio of 1 for Si-doped AlGaAs and 0.2–0.4 for Al; the Si doping concentration is 1E19 / cm³. 3 ~1E20 / cm 3 .

2. The semiconductor laser according to claim 1, characterized in that: The N-type capping layer is made of Si-doped AlGaAs, with a Si-doped AlGaAs content of 1 part by weight and an Al content of 0.3–0.6 parts by weight; the Si doping concentration is 1E17 / cm³. 3 ~1E19 / cm 3 ; The N-type transition layer is made of Si-doped AlGaAs, with a Si-doped AlGaAs content of 1 part by weight and an Al content of 0.3–0.6 parts by weight; the Si doping concentration is 1E17 / cm³. 3 ~1E18 / cm 3 ; The N-type waveguide layer is made of Si-doped AlGaAs, with a Si-doped AlGaAs weight ratio of 1 and an Al weight ratio of 0.3–0.6; the Si doping concentration is 1E17 / cm³. 3 ~1E18 / cm 3 .

3. The semiconductor laser according to claim 2, characterized in that: The thickness of the N-type capping layer ranges from 0.5 micrometers to 2 micrometers; The thickness of the N-type transition layer ranges from 0.5 micrometers to 1 micrometer; The thickness of the N-type waveguide layer ranges from 0.1 micrometers to 3 micrometers; The thickness of the N-type loss waveguide layer ranges from 0.5 micrometers to 2 micrometers.

4. The semiconductor laser according to claim 1, characterized in that: The active layer is a barrier / quantum well / barrier structure, and the material of the active layer is AlGaAs / InGaAs / AlGaAs material, with a weight part of AlGaAs / InGaAs / AlGaAs material of 1, a weight part of In of 0 to 0.5, and a weight part of Al of 0 to 0.5; the weight parts of In and Al are not both 0.

5. The semiconductor laser according to claim 4, characterized in that: In the aforementioned barrier / quantum well / barrier structure, the thickness of the barrier ranges from 1 nanometer to 200 nanometers, and the thickness of the quantum well ranges from 1 nanometer to 20 nanometers; the emission wavelength of the active layer is from 700 nanometers to 1200 nanometers.

6. The semiconductor laser according to claim 1, characterized in that: The p-type capping layer is made of C-doped AlGaAs, with a weight ratio of 1 part C-doped AlGaAs and a weight ratio of 0.3 to 0.6 parts Al; the C doping concentration is 1E17 / cm³. 3 ~1E19 / cm 3 ; The P-type waveguide layer is made of C-doped AlGaAs, with a weight ratio of 1 for C-doped AlGaAs and 0.3–0.6 for Al; the C doping concentration is 1E16 / cm³. 3 ~1E18 / cm 3 .

7. The semiconductor laser according to claim 6, characterized in that: The thickness of the P-type capping layer ranges from 0.1 micrometers to 3 micrometers; The thickness of the P-type waveguide layer ranges from 0.1 micrometers to 10 micrometers.

8. The semiconductor laser according to claim 1, characterized in that: The substrate layer is made of GaAs; the thickness of the P-type electrode layer ranges from 200 nanometers to 500 nanometers, and the material of the P-type electrode layer is an alloy of at least two of titanium, platinum, gold, nickel, or germanium. The thickness of the N-type electrode layer ranges from 200 nanometers to 500 nanometers, and the material of the N-type electrode layer is an alloy material formed from at least two of the following: titanium, platinum, gold, nickel, or germanium.

9. A method for fabricating a semiconductor laser according to claim 1, characterized in that: The preparation method includes the following steps: S1. An epitaxial structure is fabricated by sequentially depositing an N-type capping layer, an N-type loss waveguide layer, an N-type transition layer, an N-type waveguide layer, an active region layer, a P-type waveguide layer, and a P-type capping layer on a substrate. S2. A ridge waveguide structure is formed on the epitaxial structure by a single photolithography etching process; S3. An insulating material layer is grown on the surface of the P-type capping layer in the epitaxial structure, and a patterned current injection window is formed on the surface of the insulating material layer by photolithography etching; a P-type electrode layer is grown. S4. Thin the substrate layer and grow an N-type electrode layer; Annealing, cleavage into chips, and fabrication is complete.

10. The method for fabricating a semiconductor laser according to claim 9, characterized in that: In step S4, the thickness of the thinned substrate layer ranges from 100 micrometers to 300 micrometers; the insulating material layer is made of SiO2 or Si3N4, and the thickness of the insulating material layer ranges from 50 nanometers to 1000 nanometers.

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