Semiconductor laser element with polarization regulation and control layer and manufacturing method thereof

Abstract

The invention discloses a semiconductor laser element with a polarization regulation and control layer and a manufacturing method of the semiconductor laser element, and belongs to the technical field of semiconductor optoelectronic devices. Comprising an n-type semiconductor layer, a p-type semiconductor layer and an active region arranged between the n-type semiconductor layer and the p-type semiconductor layer, and the active region comprises a quantum well layer and a quantum barrier layer. The key point of the invention is that a polarization regulation and control layer is additionally arranged between the active region and the p-type semiconductor layer. The material composition and / or the strain state of the polarization regulation and control layer are configured, so that the direction of a first net polarization field generated in the polarization regulation and control layer is opposite to the direction of a second net polarization field in the quantum barrier layer closest to the p-type semiconductor layer in the active region. According to the design of the reverse polarization field, the total polarization intensity can be effectively counteracted at the interface of the two, so that the polarization charge density of the interface is remarkably reduced, the energy band structure of the active region is flattened, and the quantum limited stark effect caused by the built-in polarization field is weakened.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and more particularly to a semiconductor light-emitting device. More specifically, this invention relates to a semiconductor laser element based on a group III nitride material system, and more particularly to a semiconductor laser element whose performance is improved by optimizing the epitaxial structure design to modulate the built-in polarization field, and the corresponding manufacturing method thereof. Background Technology

[0002] Gallium nitride (GaN), a representative of III-V group nitride semiconductor materials, has become a core material for manufacturing blue-green light-emitting diodes due to its excellent physical properties such as wide bandgap, high thermal conductivity, and high chemical stability. Currently, the most commercially mature and cost-effective technology is heteroepitaxial growth on c-plane (i.e.,

[0001] crystal orientation) sapphire or silicon carbide substrates.

[0003] However, group III nitride materials (such as GaN, AlN, InN, and their alloys) generally possess a non-centrosymmetric wurtzite crystal structure. This structural characteristic leads to strong spontaneous polarization along the c-axis. Furthermore, in constructing multilayer heterojunction structures required for laser devices (e.g., InGaN / GaN quantum wells), significant strain is introduced due to lattice mismatch between different component materials, resulting in piezoelectric polarization. Spontaneous polarization and piezoelectric polarization together constitute a strong built-in polarization field.

[0004] In the core light-emitting region of a semiconductor laser device—the active region (typically an InGaN / GaN multi-quantum-well structure)—the built-in polarization field generates a strong electrostatic field within the quantum well layer. This electrostatic field causes a severe tilt in the conduction and valence bands of the quantum well, a phenomenon known as the quantum confinement Stark effect. QCSE (Quantum Confinement Stark Effect) can have a series of serious adverse effects: 1. Reduced radiative recombination efficiency: The tilted energy band pushes the wavefunctions of electrons and holes to opposite sides of the quantum well, resulting in reduced spatial overlap. This directly reduces the radiative recombination probability of electron-hole pairs, thereby decreasing the device's internal quantum efficiency; 2. Increasing the threshold current density: To achieve the carrier concentration required for laser lasing, more current needs to be injected to fill the energy level states separated by QCSE, which leads to an increase in the device's threshold current density (J). th The temperature rises significantly, increasing the device's power consumption and heat generation; 3. Causes a blue shift in wavelength: As the injection current increases, the injected carriers have a shielding effect on the built-in polarization field, causing the energy band to flatten and resulting in a widening of the effective bandgap and a significant blue shift in the emission wavelength. This severely affects the stability of the laser's output wavelength.

[0005] To mitigate the problem of electron leakage from the active region to the p-type cladding, conventional laser structures typically insert a high-aluminum AlGaN electron blocking layer between the active region and the p-type cladding. However, the traditional p-AlGaN EBL itself exhibits polarization effects. In typical Ga-polar grown structures, the net polarization directions of both the GaN quantum barrier layer and the AlGaN EBL layer point towards the [000-1] direction (i.e., towards the substrate). Therefore, at the interface between the final quantum barrier layer and the EBL, the difference in polarization intensity between the two layers generates an interface polarization charge in the same direction. This not only fails to alleviate the problem but further exacerbates the band bending of the quantum well closest to the p-type region, worsening the QCSE (Quality Conversion Effect).

[0006] Although growth on non-polar (such as m-plane) or semi-polar substrates can fundamentally eliminate or reduce polarization effects, the immature fabrication technology, low crystal quality, and extremely high cost of such substrates severely restrict their large-scale commercial application.

[0007] Therefore, how to proactively and effectively compensate for or offset the harmful polarization field in the active region through innovative epitaxial structure design on the mature and low-cost c-plane epitaxial growth technology route, thereby fundamentally solving the performance bottleneck caused by QCSE, is a key technical problem that urgently needs to be solved in the field of group III nitride semiconductor lasers. Summary of the Invention

[0008] The main objective of this invention is to overcome the aforementioned deficiencies of the prior art and provide a novel semiconductor laser element and its manufacturing method. Specifically, this invention aims to solve the quantum confinement Stark effect (QCSE) problem caused by the strong built-in polarization field in existing group III nitride semiconductor laser elements grown on the c-plane, and the resulting series of performance bottlenecks such as low quantum efficiency, high threshold current, limited output power, and wavelength instability.

[0009] To achieve the above objectives, a first aspect of the present invention provides a semiconductor laser element. The semiconductor laser element comprises, sequentially, an n-type semiconductor layer, an active region, and a p-type semiconductor layer. The active region includes at least one quantum well layer and at least one quantum barrier layer.

[0010] The core innovation of this invention lies in the fact that the semiconductor laser element also includes a specially designed polarization control layer. This polarization control layer is strategically disposed between the active region and the p-type semiconductor layer. Crucially, the material composition of the polarization control layer and / or its strain state within the device are precisely configured to generate a first net polarization field, the direction of which is opposite to the direction of the second net polarization field generated within the quantum barrier layer (i.e., the last quantum barrier layer) adjacent to the p-type semiconductor layer in the active region.

[0011] Here, "net polarization field" refers to the electric field equivalent to the vector sum of the spontaneous polarization and piezoelectric polarization of the material. In a typical GaN-based laser grown on a Ga surface (

[0001] direction), the second net polarization field within the GaN quantum barrier layer typically points in the [000-1] direction (i.e., away from the growth surface and towards the substrate). This invention, through the design of the polarization control layer, generates a first net polarization field pointing in the

[0001] direction (i.e., towards the growth surface).

[0012] Through this "polarization reversal" design, at the interface between the last quantum barrier layer and the polarization control layer in the active region, the two polarization field vectors in opposite directions cancel each other out. This results in a decrease in the total polarization intensity difference at the interface (ΔP=P). 调控层 -P 势垒层 The polarization charge density accumulated at the interface is significantly reduced, and even reversed in sign. The macroscopic effect is that it effectively "flattens" the band structure of the active region, especially the quantum well closest to the p-type region, fundamentally suppressing the quantum confinement Stark effect.

[0013] In a preferred embodiment, the semiconductor laser element is a group III nitride semiconductor laser element, and its functional layers, including an n-type semiconductor layer, a p-type semiconductor layer, a quantum well layer, a quantum barrier layer, and a polarization control layer, are all composed of group III nitride materials. These materials are typically epitaxially grown along the c-axis polarity direction of the wurtzite structure.

[0014] To achieve the aforementioned polarization reversal design, this invention proposes a specific material system scheme. In a particularly preferred embodiment, the polarization control layer is a quaternary or ternary group III nitride alloy Al. u In v Ga 1-u-v N, where u≥0, v>0, and u+v≤1. The physical mechanism of this selection is as follows: Spontaneous polarization modulation: In group III nitrides, the spontaneous polarization direction of AlN and GaN points to [000-1], while the spontaneous polarization direction of InN is opposite, pointing to

[0001] . By introducing an appropriate amount of indium (In) component (i.e., v>0) into conventional AlGaN or GaN, the "reverse" spontaneous polarization contribution of InN can be used to offset or even surpass the "positive" spontaneous polarization contribution of AlN and GaN.

[0015] Piezoelectric polarization synergy: when Al u In v Ga 1-u-v When an N-layer is epitaxially grown on a GaN layer, which is typically used as a quantum barrier, its lattice constant can be increased by controlling its composition, thus subjecting it to tensile stress. This tensile stress generates a piezoelectric polarization field pointing in the [000-1] direction.

[0016] The essence of this invention lies in the fact that, through the synergistic regulation of the aluminum component u and the indium component v, the "reverse" spontaneous polarization effect introduced by InN exceeds the sum of the "positive" spontaneous polarization contribution (from AlN and GaN) and the "positive" piezoelectric polarization contribution, ultimately making the Al... u In v Ga 1-u-v The direction of the first net polarization field of the Nth layer (the vector sum of spontaneous polarization and piezoelectric polarization) was successfully reversed to point in the

[0001] direction.

[0017] In a further embodiment, the polarization control layer not only performs polarization control but is also designed to simultaneously possess efficient electron blocking functionality, thus replacing the traditional electron blocking layer (EBL). This is achieved through the appropriate selection of the Al composition u. A higher Al composition u can provide a sufficiently large conduction band level, forming an effective blocking barrier for electrons injected from the active region. For example, if the p-type semiconductor layer includes a p-Al... w Ga 1-w With an N-cladding layer, a polarization control layer Al can be designed. u In v Ga 1-u-v The aluminum component u of N is less than w to facilitate hole injection, while its indium component v>0 to achieve polarization reversal.

[0018] To achieve optimized performance, the polarization control layer can have various structural forms, such as: Single homogeneous composition layer: Al throughout the entire layer u In v Ga 1-u-v With a constant N component, process control is relatively simple.

[0019] Compositionally graded layers: The composition of the layer changes smoothly from the side closer to the active region to the side closer to the p-type region. For example, the side closer to the active region can have a higher In composition to achieve the strongest polarization compensation, while the side closer to the p-type region can have a higher Al composition to provide the strongest electron blocking barrier.

[0020] Superlattice structure layer: composed of alternating stacks of thin layers with two or more different compositions (such as InGaN / AlGaN). Through careful design of the sublayer thickness and composition, the equivalent average polarization characteristics meet the polarization reversal requirements of this invention.

[0021] The thickness of the polarization control layer is also a key parameter, preferably ranging from 1 nm to 20 nm. If the thickness is too thin, the polarization compensation effect will be insignificant; if the thickness is too large, excessive cumulative strain may lead to a decrease in crystal quality and the generation of defects such as dislocations.

[0022] A second aspect of the present invention provides a method for manufacturing the aforementioned semiconductor laser element. The method includes sequentially epitaxially growing an n-type semiconductor layer, an active region, a polarization control layer, and a p-type semiconductor layer on a substrate. The core step involves, in the step of epitaxially growing the polarization control layer, actively controlling the material composition and / or strain state of the polarization control layer by precisely controlling the parameters of the epitaxial growth process (such as metal-organic chemical vapor deposition (MOCVD) or molecular beam epitaxy (MBE)) to achieve that the directions of the first net polarization field and the second net polarization field are opposite.

[0023] In one specific implementation, the method employs MOCVD. During the growth of the polarization control layer, the molar flow rate and flow ratio of the metal-organic source (such as trimethylgallium™Ga, trimethylaluminum™Al, trimethylindium™In), as well as process parameters such as growth temperature and reaction chamber pressure, are precisely controlled to precisely control the incorporation ratio of Al, In, and Ga in the solid phase, thereby obtaining the target component Al. u In v Ga 1-u-v N is used to control the strain state when it grows on the underlying GaN layer, ultimately achieving the preset polarization reversal effect.

[0024] Compared with existing technologies, this invention achieves the following significant advantages by introducing a precisely designed polarization control layer: 1. Fundamentally suppressing QCSE: By generating a net polarization field opposite to the direction of the barrier layer in the active region, the interfacial polarization charge is compensated at its source, effectively flattening the band structure of the active region and significantly reducing the quantum confinement Stark effect; 2. Improved Device Performance: Reduced QCSE directly leads to increased overlap of electron and hole wavefunctions, thereby significantly improving radiative recombination efficiency and internal quantum efficiency. This further results in a significant reduction in threshold current density, an increase in optical output power, and an improvement in overall electro-optical conversion efficiency. 3. Enhanced operational stability: Due to the effective compensation of the built-in polarization field, the shielding effect of injected carriers on the energy band is weakened, effectively suppressing the blue shift phenomenon of the emission wavelength of the device with the change of operating current, thus enhancing the operational stability of the laser; 4. Good process compatibility: This technical solution is based entirely on mature and low-cost c-plane epitaxial growth process. It does not require the use of expensive non-polar or semi-polar substrates. It only requires adding or replacing one layer in the existing epitaxial structure. The process modification is small and it is easy to integrate into the existing production line. It has extremely high industrialization value and cost-effectiveness. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the process for manufacturing semiconductor laser components. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the present invention clearer, specific embodiments of the present invention will be described in detail below. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the scope of protection of the invention.

[0027] Example 1 This embodiment provides a high-performance GaN-based semiconductor laser device for emitting blue light (e.g., with a center wavelength of 450 nm). The device is epitaxially grown on a c-plane (0001) sapphire substrate using a metal-organic chemical vapor deposition (MOCVD) device.

[0028] Its specific epitaxial structure, from the substrate upwards, includes: Buffer layer (not defined in the claims): First, a low-temperature (approximately 550°C) GaN nucleation layer with a thickness of approximately 25 nm is grown on the substrate; then, the temperature is raised to a high temperature (approximately 1050°C) to grow a high-temperature GaN buffer layer with a thickness of 2 μm to improve crystal quality and reduce dislocation density.

[0029] n-type semiconductor layer: This layer mainly includes: A 2.5 μm thick n-type GaN underlayer is used, with silicon (Si) as the n-type dopant and a doping concentration of 5 × 10⁻⁶. 18 cm -3 This layer also serves as the lower waveguide layer.

[0030] Active region: Employs a multiple quantum well (MQW) structure, consisting of three cycles of InGaN / GaN quantum well / barrier pairs.

[0031] Quantum potential well layer: In 0.15 Ga 0.85 The N-layer has a thickness of 3.0 nm.

[0032] Quantum barrier layer: GaN layer, 12nm thick.

[0033] None of these layers were intentionally doped. In this structure, the topmost layer, adjacent to the subsequent polarization control layer, is a 12 nm thick GaN quantum barrier layer. According to the polarization theory of wurtzite GaN, under Ga surface growth conditions, this GaN quantum barrier layer and the underlying In... 0.15 Ga 0.85 At the interface of the N-quantum well layer, a net polarization field is generated, which points in the [000-1] direction (i.e. away from the growth surface and towards the substrate). This is what is referred to as the "second net polarization field" in this invention.

[0034] Polarization control layer: This is the core functional layer of this invention. It is grown directly on the last GaN quantum barrier layer in the active region.

[0035] Material: Al 0.12 In 0.07 Ga 0.81 Nitrogen quaternary alloy.

[0036] Thickness: 6nm.

[0037] Doping: No intentional doping has been performed.

[0038] Design Principles and Implementation: Choosing AI 0.12 In 0.07 Ga 0.81 The specific component N is the result of precise physical calculations and simulation optimization. The net polarization intensity of this layer is spontaneous polarization (P). sp ) and piezoelectric polarization (P p The vector sum of ).

[0039] Spontaneous polarization: Because of P sp The sign of (InN) and P sp (AlN) and P sp (GaN) On the contrary, the negative contribution of the introduced 7% In component can effectively offset the positive contributions of the 12% Al component and 81% GaN component, resulting in a significant reduction in the total spontaneous polarization component, or even a reversal of its direction.

[0040] Piezoelectric polarization: the Al 0.12 In 0.07 Ga 0.81 The N layer has a larger lattice constant than the underlying GaN layer, and therefore is subjected to tensile stress, generating a piezoelectric polarization field pointing in the [000-1] direction.

[0041] Through the coordinated control of u and v, the direction of the total net polarization field (i.e., the first net polarization field) within this layer was successfully reversed to point towards

[0001] (i.e., towards the growth surface). This first net polarization field pointing towards

[0001] is exactly opposite in direction to the second net polarization field pointing towards [000-1] within the aforementioned GaN quantum barrier layer. Therefore, at the interface between the active region and the polarization control layer, the interaction of the two polarization fields with opposite directions leads to a significant reduction in the total polarization intensity difference ΔP at the interface, thereby significantly weakening the band bending in this region and suppressing QCSE. Furthermore, this Al 0.12 In 0.07 Ga 0.81 The bandgap of the N-layer (approximately 3.6 eV) is greater than the effective bandgap of the active region, effectively blocking electrons from leaking into the p-type region. Therefore, it also plays the role of a highly efficient electron blocking layer.

[0042] p-type semiconductor layer: This layer mainly includes: o A layer of p-type Al with a thickness of 0.6 μm 0.08 Ga 0.92 The nitrogen layer is top-clad with magnesium (Mg) as the p-type dopant at a concentration of 2 × 10⁻⁶. 19 cm -3 .

[0043] p-type contact layer: a 20nm thick heavily doped p-type contact layer + -GaN layer, with a Mg doping concentration of approximately 1×10⁻⁶ 20 cm -3 It is used to form ohmic contacts with low resistivity.

[0044] After epitaxial growth, the epitaxial wafer is annealed to activate the Mg acceptors. Subsequently, a ridge waveguide structure is formed using standard semiconductor photolithography, dry etching (such as ICP etching), metal evaporation, and lift-off processes. P-type electrodes (e.g., Ni / Au alloy) and n-type electrodes (e.g., Ti / Al / Ni / Au stack) are fabricated on the p-type contact layer and the n-type GaN cladding exposed by etching, respectively, and rapid thermal annealing is performed to form ohmic contacts. Finally, through cleavage, cavity surface deposition of high-reflectivity / anti-reflection dielectric films, and other processes, the laser device is finally packaged.

[0045] Performance Comparison: For comparison, a conventional laser element with the exact same structure except for the polarization control layer was fabricated, using a traditional 20nm thick p-Al layer. 0.20Ga 0.80 N is used as EBL. Tests were conducted in continuous-wave (CW) mode at room temperature. The threshold current density of the laser element in this embodiment was 3.8 kA / cm², compared to the comparative device. 2 Reduced to 2.4 kA / cm 2 The reduction is approximately 37%. Under the condition of injection current twice the threshold, the optical output power of the device in this embodiment is increased by approximately 40% compared with the comparative device, and the blue shift of its emission wavelength as the current increases from the threshold to twice the threshold is reduced from 5 nm in the comparative device to 1.5 nm.

[0046] Example 2 This embodiment provides a semiconductor laser element with another structure, most of which is similar to that of Embodiment 1, with the main difference being the structural design of the polarization control layer.

[0047] In this embodiment, the polarization control layer is no longer a homogeneous layer with a single component, but rather an Al layer with gradually varying components. u In v Ga 1-u-v N-layer. Specifically, this layer has a total thickness of 10 nm, and its composition changes smoothly and linearly from the side near the active region to the side near the p-type region: Starting point (at the interface with the active region): composition is Al 0.05 In 0.10 Ga 0.85 N. The In composition here is relatively high, and the Al composition is relatively low, which is intended to generate the strongest reverse polarization field to maximize compensation for the polarization field at the active region interface and to flatten the energy band.

[0048] Terminal (at the p-type cladding interface): Composition is Al 0.18 In 0.02 Ga 0.80 N. The Al content is significantly increased here, while the In content is decreased, in order to form a higher electron blocking barrier to ensure excellent electron confinement and prevent electron leakage.

[0049] The advantage of this gradient structure design lies in its ability to create a smooth transition barrier, avoiding spikes or dips in carrier transport paths that might occur due to abrupt band changes. This facilitates hole injection from the p-type layer into the active region. Simultaneously, it achieves optimal spatial allocation of functions: enhancing compensation at the interfaces most in need of polarization compensation and strengthening blocking in regions most in need of electron blocking. The resulting technical performance is comparable to that of Example 1, and even exhibits superior linearity and higher slope efficiency in certain high injection current ranges.

[0050] Example 3 This embodiment describes in detail a method for manufacturing the semiconductor laser element described in Embodiment 1, which is mainly implemented in a standard reaction chamber using MOCVD technology.

[0051] Step S1: Substrate preparation and buffer layer growth A 2-inch c-plane sapphire substrate was placed on a graphite substrate in the MOCVD reaction chamber. Under an H2 atmosphere, the temperature was raised to 1100°C and held for 10 minutes to perform high-temperature baking to clean the surface of the substrate. Subsequently, the temperature was lowered to 550°C, and trimethylgallium (TMGa) and ammonia (NH3) were introduced to grow a 25 nm low-temperature GaN nucleation layer. Afterward, the temperature was raised back to 1050°C, and TMGa and NH3 were introduced again to grow a 2 μm thick high-temperature GaN buffer layer.

[0052] Step S2: n-type semiconductor layer epitaxy At 1050℃, TMGa and NH3 were continuously introduced, and silane (SiH4) was introduced as an n-type dopant source to grow a 2.5 μm thick n-GaN lower cladding at a set flow rate ratio. The target Si doping concentration was 5 × 10⁻⁶. 18 cm -3 .

[0053] Step S3: Active region extension The SiH4 supply was stopped, and the reaction chamber temperature was lowered to approximately 780°C, which is a typical temperature window for InGaN growth. By precisely controlling the valve switching program of the MOCVD system, the trimethylindium (TMIn) source was periodically switched on and off, and the flow ratio of TMGa to TMIn was adjusted to alternately grow three pairs of InGaN. 0.15 Ga 0.85 N quantum well layer (3.0 nm) and GaN quantum barrier layer (12 nm).

[0054] Step S4: Polarization control layer epitaxy (core step) After growing the final GaN quantum barrier layer, the growth was continued without interruption, and the temperature was fine-tuned to approximately 820°C. At this point, three metal-organic sources—TMGa, TMIn, and trimethylaluminum (TMAl)—were precisely introduced simultaneously and reacted with NH3. The molar flow ratio of TMGa, TMIn, and TMAl was precisely set to a pre-calculated value using the mass flow controller (MFC) of the MOCVD equipment. This value corresponds to an atomic ratio of Al, In, and Ga in the solid-phase material that is approximately 12%, 7%, and 81%, respectively, under the current growth temperature and pressure. These growth conditions were maintained until a thickness of 6 nm was reached, at which point the supply of all metal sources was stopped. The selection of flow rates and temperature in this step was based on extensive experimental data and theoretical calculations, with the core objective of ensuring the final formation of Al... 0.12 In 0.07 Ga0.81 The net polarization direction of the N layer (the sum of spontaneous polarization and piezoelectric polarization) is opposite to the net polarization direction of the underlying GaN barrier layer.

[0055] Step S5: Epitaxy of p-type semiconductor layer and contact layer The growth temperature was increased to approximately 980℃, and TMAl, TMGa, and NH3 were introduced. Simultaneously, magnesia-diocene (Cp₂Mg) was introduced as a p-type dopant source to grow a 0.6 μm thick p-Al layer. 0.08 Ga 0.92 N-clad layer. Subsequently, the supply of TMAl was stopped, and a 20 nm thick p-clad layer was grown at a higher Cp2Mg flow rate. + -GaN contact layer.

[0056] Step S6: Subsequent chip manufacturing process The epitaxially grown wafer is removed and subjected to rapid thermal annealing (e.g., 750°C, 20 minutes) in an N2 atmosphere to activate the Mg acceptors. Then, as described in Example 1, standard chip manufacturing processes are performed, including photolithography, etching, electrode fabrication, cleavage, and coating, to finally complete the device fabrication.

[0057] Those skilled in the art should understand that the above description is merely a preferred embodiment of the present invention and is 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 scope of protection of the present invention. For example, the substrate can be SiC, GaN, or Si, etc.; the specific thickness, composition, and doping concentration of each functional layer can be adjusted according to the target wavelength and performance requirements; the position of the polarization control layer is not limited to being adjacent to the active region, but can also be at any suitable position between the active region and the p-type layer, as long as the reverse polarization field it generates can effectively modulate the energy band of the active region. In addition, the polarization control layer can also be designed as a superlattice structure, for example, composed of several periods of thin InGaN / AlGaN pairs, and through careful design of the sublayer thickness and composition, its equivalent average polarization characteristics can meet the requirements of the present invention. These changes and modifications do not depart from the core ideas and scope of the technical solution of the present invention.

Claims

1. A semiconductor laser element, characterized in that, include: An n-type semiconductor layer; p-type semiconductor layer; An active region is disposed between the n-type semiconductor layer and the p-type semiconductor layer, and the active region includes at least one quantum potential well layer and at least one quantum potential barrier layer; as well as A polarization control layer is provided, wherein the polarization control layer is disposed between the active region and the p-type semiconductor layer; The polarization control layer is configured such that the direction of the first net polarization field generated therein is opposite to the direction of the second net polarization field generated in the quantum barrier layer adjacent to the p-type semiconductor layer in the active region.

2. The semiconductor laser element according to claim 1, characterized in that, The n-type semiconductor layer, the p-type semiconductor layer, the active region, and the polarization control layer are all group III nitride materials epitaxially grown along the c-axis polarity direction of the wurtzite structure.

3. The semiconductor laser element according to claim 2, characterized in that, The quantum potential well layer is made of In. x Ga 1-x N, where 0 <x<1; The quantum barrier layer is made of In. y Ga 1-y N, where 0≤y <x; as well as The polarization control layer is made of a quaternary or ternary Group III nitride alloy Al. u In v Ga 1-u-v N, where u≥0, v>0, and u+v≤1.

4. The semiconductor laser element according to claim 3, characterized in that, The p-type semiconductor layer includes a p-type cladding layer, and the polarization control layer is disposed between the active region and the p-type cladding layer and configured to simultaneously function as an electron blocking layer; wherein, the material of the p-type cladding layer is Al. w Ga 1-w N (w>0), the polarization control layer Al u In v Ga 1-u-v The aluminum component u of N is less than the aluminum component w of the p-type cladding, and its indium component v is sufficient to reverse the direction of the first net polarization field.

5. The semiconductor laser element according to claim 1, characterized in that, The first net polarization field is opposite in direction to the second net polarization field, and is used to generate an interface polarization charge at the interface between the active region and the polarization control layer. The electric field formed by the interface polarization charge can at least partially compensate for the band bending caused by the polarization effect inside the active region, thereby reducing the quantum confinement Stark effect.

6. The semiconductor laser element according to claim 1, characterized in that, It also meets at least one of the following conditions: a) The thickness of the polarization control layer is set to 1 nm to 20 nm; b) The active region is a multi-quantum potential well structure comprising alternating stacked layers of the quantum potential well layer and layers of the quantum potential barrier layer; c) The polarization control layer is a single uniform composition layer, a composition gradient layer, or a superlattice structure layer composed of thin layers of two or more group III nitride materials with different compositions.

7. A method for manufacturing a semiconductor laser element, characterized in that, Includes the following steps: Provide a substrate; An n-type semiconductor layer, an active region, a polarization control layer, and a p-type semiconductor layer are epitaxially grown sequentially on the substrate. The active region includes at least one quantum well layer and at least one quantum barrier layer. In the step of epitaxially growing the polarization control layer, the material composition and / or strain state of the polarization control layer are controlled by adjusting at least one process parameter during the epitaxial growth process, so that the direction of the first net polarization field formed in the polarization control layer is opposite to the direction of the second net polarization field formed in the quantum barrier layer adjacent to the p-type semiconductor layer in the active region.

8. The method according to claim 7, characterized in that, The epitaxial growth step employs metal-organic chemical vapor deposition or molecular beam epitaxy; and the step of regulating the epitaxial growth process includes: controlling at least one of the flow rate, flow ratio, growth temperature, or reaction chamber pressure of the growth source to regulate the vector sum of the spontaneous polarization intensity and the piezoelectric polarization intensity of the polarization control layer, thereby forming the first net polarization field.

9. The method according to claim 8, characterized in that, The polarization control layer is made of Al. u In v Ga 1-u-v N, the quantum barrier layer is made of GaN; the step of epitaxially growing the polarization control layer includes: simultaneously introducing an aluminum source, an indium source, and a gallium source, and controlling their flow ratio and growth conditions, so that the formed Al u In v Ga 1-u-v The net polarization direction of the N layer points towards the surface direction of epitaxial growth, while the net polarization direction of the GaN quantum barrier layer points away from the surface direction of epitaxial growth.

10. The method according to claim 7, characterized in that, In the step of epitaxially growing the polarization control layer, the polarization control layer is epitaxially grown between the active region and a p-type cladding, and its material composition and thickness are controlled so that the polarization control layer is configured to simultaneously serve as an electron blocking layer.

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