Semiconductor laser based on quantum well hybrid structure and preparation method thereof

Abstract

The invention provides a semiconductor laser based on a quantum well hybrid structure and a preparation method thereof, an active region laminated structure is formed by alternately laminating AlGaInP barrier layers and AlxGayInzP quantum well layers, and the uppermost layer and the lowermost layer of the active region laminated structure are both the AlGaInP barrier layers. Meanwhile, the Al components of the uppermost AlGaInP barrier layer and the lowermost AlGaInP barrier layer of the active region laminated structure are both larger than those of the lower limiting layer, the lower waveguide layer, the upper waveguide layer and the upper limiting layer, so that the AlGaInP barrier layer becomes a material layer with the highest Al component. And finally, the blue shift amount is locked in a range determined by the uppermost AlGaInP barrier layer and the lowermost AlGaInP barrier layer of the active region laminated structure, so that the harsh requirements on accurate control of the annealing temperature and time are reduced, and the production yield is improved. By adopting the preparation method, the whole wafer can be processed in parallel, the technological process is simple, seamless connection with an existing chip manufacturing process is achieved, and the preparation method is suitable for large-scale industrial manufacturing.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor lasers and their manufacturing technology, and in particular relates to a semiconductor laser based on a quantum well hybrid structure and its preparation method. Background Technology

[0002] Semiconductor lasers have been widely and profoundly applied in fields such as military, industrial processing, precision measurement, laser medicine, optical communication, optical storage and laser printing due to their high conversion efficiency, small size, light weight, long life, high reliability, direct modulation and easy integration with other semiconductor devices.

[0003] To meet the demand for short-wavelength lasers in specific applications and address wavelength drift caused by factors such as temperature and current during device operation, ensuring device performance stability and application adaptability, blue-shift design is typically implemented in semiconductor laser design. Quantum well intermixing (QWI) is a core technology for achieving selective bandgap modulation and wavelength blue-shifting after epitaxy in semiconductor lasers.

[0004] For AlGaInP 650nm red laser devices, traditional QWI methods, such as impurity diffusion and ion implantation, have two significant problems: 1. High process sensitivity: The final blue shift is strongly dependent on process parameters such as annealing temperature and time. Small fluctuations in these parameters during mass production can lead to a decrease in the consistency of device wavelength and yield; 2. Risk of over-doping: To achieve the target blue shift, such as 20nm~30nm, a long annealing time may be required. However, a slight over-doping may occur, causing the wavelength to blue shift beyond the design range, or even impairing the luminous efficiency of the quantum well. Summary of the Invention

[0005] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a semiconductor laser based on a quantum well hybrid structure and its fabrication method, in order to solve the problems of high process sensitivity and over-hybridization risk in the traditional QWI method for AlGaInP 650nm red laser devices.

[0006] To achieve the above and other related objectives, the present invention provides a method for fabricating a semiconductor laser based on a quantum well hybrid structure, the method comprising the following steps:

[0007] Provide semiconductor substrates;

[0008] An epitaxial stack structure is epitaxially grown on the semiconductor substrate, the epitaxial stack structure comprising, in sequence: a lower confinement layer, a lower waveguide layer, an active region stack structure, an upper waveguide layer, an upper confinement layer, and an ohmic contact layer; wherein the lower confinement layer, the lower waveguide layer, the upper waveguide layer, and the upper confinement layer are all Al-containing material layers, and the active region stack structure consists of an AlGaInP barrier layer and an Al... x Ga y In z P quantum well layers are alternately stacked, x+y+z=1, 0≤x<1, and the uppermost and lowermost layers of the active region stacked structure are both AlGaInP barrier layers, and the Al composition of the uppermost and lowermost AlGaInP barrier layers of the active region stacked structure is greater than the Al composition of the lower confinement layer, the lower waveguide layer, the upper waveguide layer and the upper confinement layer.

[0009] A patterned mask layer is formed on the epitaxial stacked structure, and the patterned mask layer exposes a non-absorption window region;

[0010] Based on the patterned mask layer, the epitaxial stacked structure is annealed after Zn diffusion to achieve quantum well hybridization in the non-absorption window region.

[0011] Optionally, the Al composition of the uppermost and lowermost AlGaInP barrier layers of the active region stacked structure is greater than the Al composition of the AlGaInP barrier layers of the other layers in the active region stacked structure.

[0012] Optionally, the Al composition content of the uppermost and lowermost AlGaInP barrier layers of the active region stacked structure is the same.

[0013] Optionally, the thickness of the AlGaInP barrier layer in the uppermost and lowermost layers of the active region stacked structure is less than the thickness of the AlGaInP barrier layer in the other layers of the active region stacked structure.

[0014] Furthermore, the thickness of the AlGaInP barrier layer at the top and bottom of the active region stacked structure is 2nm~3nm.

[0015] Optionally, the lower confinement layer is an AlInP lower confinement layer, the lower waveguide layer is an AlGaInP lower waveguide layer, the upper waveguide layer is an AlGaInP upper waveguide layer, and the upper confinement layer is an AlInP upper confinement layer.

[0016] Optionally, the semiconductor substrate is an N-type GaAs substrate.

[0017] Optionally, the epitaxial stack structure is grown using MOCVD, and Zn is diffused into the epitaxial stack structure using MOCVD.

[0018] Furthermore, the precursor source for Zn diffusion in the epitaxial stacked structure using MOCVD process is dimethyl zinc, and the protective gas is arsine.

[0019] The present invention also provides a semiconductor laser based on a quantum well hybrid structure, which is prepared by the preparation method of a semiconductor laser based on a quantum well hybrid structure as described in any one of the above claims.

[0020] As described above, the semiconductor laser based on a quantum well hybrid structure and its fabrication method of the present invention, through the design of the active region stacked structure in the epitaxial stacked structure consisting of an AlGaInP barrier layer and an Al x Ga y In z AlgaInP quantum well layers are alternately stacked, and the uppermost and lowermost layers of the active region stacked structure are AlGaInP barrier layers. Furthermore, the Al composition of the uppermost and lowermost AlGaInP barrier layers in the active region stacked structure is greater than that of the lower confinement layer, lower waveguide layer, upper waveguide layer, and upper confinement layer, making them the material layers with the highest Al composition. Therefore, during subsequent Zn diffusion and annealing in the non-absorption window region, Zn atoms diffuse in from the mask layer opening region (i.e., the non-absorption window region) into the Al... x Ga y In z The high concentration of group III vacancies in the P quantum well layer region greatly enhances the interdiffusion of In, Ga, and Al atoms, resulting in quantum well hybridization. This is because the Al composition of the AlGaInP barrier layer is relatively high compared to Al... x Ga y In z The p-quantum well layer is higher, thus possessing a higher atomic diffusion activation energy. Impurity or point defect-induced mixing first occurs in low-Al composition Al. x Ga y In zThe mixing occurs rapidly in the P-quantum well layer, achieving a blue shift of the laser wavelength. When the mixing front advances to the uppermost and lowermost AlGaInP barrier layers of the active region stacked structure with the highest Al composition, the atomic diffusion rate drops sharply, the mixing process is strongly suppressed, automatically decelerates and tends to stop, thus ultimately "locking" the blue shift within the range determined by the uppermost and lowermost AlGaInP barrier layers of the active region stacked structure, and becoming insensitive to small changes in annealing time. Therefore, this band structure design achieves a "self-stopping" effect of active layer mixing, reducing the stringent requirements for precise control of annealing temperature and time, and improving production yield. The fabrication method of this invention can also be used to process the entire wafer in parallel, with a simple process flow that seamlessly integrates with existing chip manufacturing processes, making it suitable for large-scale industrial manufacturing. Attached Figure Description

[0021] Figure 1 The diagram shown is a cross-sectional view of the epitaxial stack structure grown on a semiconductor substrate in the method for fabricating a semiconductor laser based on a quantum well hybrid structure according to the present invention.

[0022] Figure 2 The diagram shown is a cross-sectional schematic of the active region stacked structure in the epitaxial stacked structure, which is the first example.

[0023] Figure 3 The diagram shown is a cross-sectional schematic of the active region stacked structure in the epitaxial stacked structure, which is the second example.

[0024] Figure 4 The diagram shown is a cross-sectional schematic of the active region stacked structure in the epitaxial stacked structure, which is the third example.

[0025] Figure 5 The diagram shows a cross-sectional view of a patterned mask layer formed on an epitaxial stacked structure in the fabrication method of a semiconductor laser based on a quantum well hybrid structure according to the present invention.

[0026] Figure 6 Displayed as Figure 5 A schematic diagram of the planar structure.

[0027] Figure 7 The graph shows the photoluminescence (PL) test results of a semiconductor laser fabricated using the quantum well hybrid structure method of the present invention without Zn diffusion and annealing.

[0028] Figure 8 The graph shows the photoluminescence (PL) test results of a semiconductor laser fabricated using the quantum well hybrid structure method of the present invention under Zn diffusion and annealing conditions.

[0029] Figure 9 The image shows the atomic force microscopy (AFM) test results of a semiconductor laser fabricated using the quantum well hybrid structure method of the present invention without Zn diffusion and annealing.

[0030] Figure 10 The image shows the atomic force microscopy (AFM) test results of a semiconductor laser fabricated using the quantum well hybrid structure method of the present invention under Zn diffusion and annealing conditions.

[0031] Component designation explanation

[0032] 10 semiconductor substrate 11 Epitaxial stacked structure 110 Lower constraint layer 111 Lower waveguide layer 112 Active region stacked structure 113 AlGaInP barrier layer 114 <![CDATA[Al x Ga y In z P quantum well layer]]> 115 upper waveguide layer 116 upper constraint layer 117 Ohmic contact layer 12 mask layer 13 Non-absorption window region Detailed Implementation

[0033] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0034] Please see Figures 1 to 10 It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the illustrations only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0035] This embodiment provides a method for fabricating a semiconductor laser based on a quantum well hybrid structure, the method comprising the following steps:

[0036] S1 provides a semiconductor substrate;

[0037] S2, an epitaxial stacked structure is epitaxially grown on the semiconductor substrate. The epitaxial stacked structure sequentially includes: a lower confinement layer, a lower waveguide layer, an active region stacked structure, an upper waveguide layer, an upper confinement layer, and an ohmic contact layer; wherein the lower confinement layer, the lower waveguide layer, the upper waveguide layer, and the upper confinement layer are all Al-containing material layers, and the active region stacked structure consists of an AlGaInP barrier layer and an Al... x Ga y In zP quantum well layers are alternately stacked, x+y+z=1, 0≤x<1, and the uppermost and lowermost layers of the active region stacked structure are both AlGaInP barrier layers, and the Al composition of the uppermost and lowermost AlGaInP barrier layers of the active region stacked structure is greater than the Al composition of the lower confinement layer, the lower waveguide layer, the upper waveguide layer and the upper confinement layer.

[0038] S3, a patterned mask layer is formed on the epitaxial stacked structure, the patterned mask layer exposing the non-absorption window region;

[0039] S4, Zn diffusion is performed on the epitaxial stacked structure based on the patterned mask layer, followed by annealing, to achieve quantum well hybridization in the non-absorption window region.

[0040] The method for fabricating a semiconductor laser based on a quantum well hybrid structure in this embodiment involves designing an active region stacked structure in an epitaxial stacked structure consisting of an AlGaInP barrier layer and an Al x Ga y In z AlgaInP quantum well layers are alternately stacked, and the uppermost and lowermost layers of the active region stacked structure are AlGaInP barrier layers. Furthermore, the Al composition of the uppermost and lowermost AlGaInP barrier layers in the active region stacked structure is greater than that of the lower confinement layer, lower waveguide layer, upper waveguide layer, and upper confinement layer, making them the material layers with the highest Al composition. Therefore, during subsequent Zn diffusion and annealing in the non-absorption window region, Zn atoms diffuse in from the mask layer opening region (i.e., the non-absorption window region) into the Al... x Ga y In z The high concentration of group III vacancies in the P quantum well layer region greatly enhances the interdiffusion of In, Ga, and Al atoms, resulting in quantum well hybridization. This is because the Al composition of the AlGaInP barrier layer is relatively high compared to Al... x Ga y In z The p-quantum well layer is higher, thus possessing a higher atomic diffusion activation energy. Impurity or point defect-induced mixing first occurs in low-Al composition Al. x Ga y In zThe mixing occurs rapidly in the P-quantum well layer, achieving a blue shift of the laser wavelength. When the mixing front advances to the top and bottom AlGaInP barrier layers of the active region stacked structure with the highest Al composition, the atomic diffusion rate drops sharply, the mixing process is strongly suppressed, automatically decelerates and tends to stop, thus ultimately "locking" the blue shift within the range determined by the top and bottom AlGaInP barrier layers of the active region stacked structure, and becoming insensitive to small changes in annealing time. Therefore, this band structure design achieves a "self-stopping" effect of active layer mixing, reducing the stringent requirements for precise control of annealing temperature and time, and improving production yield. The fabrication method of this embodiment can also be used for parallel processing of the entire wafer, with a simple process flow, seamless integration with existing chip manufacturing processes, and is suitable for large-scale industrial manufacturing.

[0041] The fabrication method of the semiconductor laser based on the quantum well hybrid structure of this embodiment will be described in detail below with reference to the specific accompanying drawings.

[0042] like Figure 1 As shown, step S1 is performed first, providing a semiconductor substrate 10.

[0043] The semiconductor substrate 10 can be made of any material suitable for fabricating a semiconductor laser. In this embodiment, an N-type GaAs substrate (offset angle 15°) is selected.

[0044] like Figures 1 to 4 As shown, step S2 is then performed, where an epitaxial stacked structure 11 is epitaxially grown on the semiconductor substrate 10. The epitaxial stacked structure 11 sequentially includes: a lower confinement layer 110, a lower waveguide layer 111, an active region stacked structure 112, an upper waveguide layer 115, an upper confinement layer 116, and an ohmic contact layer 117. The lower confinement layer 110, the lower waveguide layer 111, the upper waveguide layer 115, and the upper confinement layer 116 are all Al-containing material layers. The active region stacked structure 112 consists of an AlGaInP barrier layer 113 and an Al... x Ga y In z P quantum well layers 114 are alternately stacked, x+y+z=1, 0≤x<1, and the uppermost and lowermost layers of the active region stacked structure 112 are both AlGaInP barrier layers 113, and the Al composition of the uppermost and lowermost AlGaInP barrier layers 113 of the active region stacked structure 112 is greater than the Al composition of the lower confinement layer 110, the lower waveguide layer 111, the upper waveguide layer 115 and the upper confinement layer 116.

[0045] The active region stacked structure 112 contains an AlGaInP barrier layer 113 and an Al x Ga y In zThe p-quantum well layer 114 is the core structural unit for realizing carrier confinement, gain control, and high-performance laser emission, in which Al x Ga y In z The AlGaInP quantum well layer 114 is a thin layer made of narrow-bandgap semiconductor material and is the core region for carrier recombination luminescence. The AlGaInP barrier layer 113 is a wide-bandgap semiconductor material that coats both sides of the quantum well, serving a dual function of carrier confinement and optical confinement. Therefore, the Al content in the AlGaInP barrier layer 113 is greater than that in Al. x Ga y In z The content of Al in the P quantum well layer 114 is adjusted to achieve a wide bandgap in the barrier layer and a narrow bandgap in the quantum well layer; in addition, the AlGaInP barrier layer 113 and Al x Ga y In z The content of Al component in the P quantum well layer 114 is selected according to actual design requirements. x Ga y In z The P quantum well layer 114 can also be x=0, that is, it does not contain Al component, and is a GaInP quantum well layer.

[0046] In this embodiment, the Al composition of the uppermost and lowermost AlGaInP barrier layers 113 of the active region stacked structure 112 is greater than that of the lower confinement layer 110, lower waveguide layer 111, upper waveguide layer 115, and upper confinement layer 116, making them the material layers with the highest Al composition. This allows Zn atoms to diffuse into the Al during subsequent Zn diffusion and annealing in the non-absorption window region. x Ga y In z The high concentration of group III vacancies in the P quantum well layer 114 region enhances the interdiffusion of In, Ga, and Al atoms, achieving quantum well hybridization. This is because the Al composition of the AlGaInP barrier layer 113 is relatively lower than that of Al. x Ga y In z The p-quantum well layer 114 is higher, thus possessing a higher atomic diffusion activation energy. Impurity or point defect-induced mixing occurs primarily in low-Al composition Al. x Ga y In zThe blue shift of the laser wavelength occurs rapidly in the P quantum well layer 114. However, since the Al composition is largest in the AlGaInP barrier layer 113 at the top and bottom of the active region stacked structure 112, the atomic diffusion rate drops sharply when the mixing front advances to these two layers. The mixing process is strongly suppressed, automatically slows down and tends to stop, so that the atomic diffusion range cannot spread to the region outside the active region stacked structure 112. Thus, the blue shift is "locked" within the range determined by the AlGaInP barrier layer at the top and bottom of the active region stacked structure. This makes it insensitive to small changes in annealing time, achieving a "self-stopping" effect of active layer mixing through this band structure design.

[0047] As an example, the epitaxial stack structure 11 can be formed using processes including but not limited to metal-organic chemical vapor deposition (MOCVD) or molecular beam epitaxy (MBE).

[0048] As an example, a buffer layer (not shown in the figure) may be epitaxially grown between the semiconductor substrate 10 and the epitaxial stacked structure 11 to alleviate lattice mismatch and thermal mismatch between the semiconductor substrate 10 and the epitaxial stacked structure 11.

[0049] As a preferred example, the Al composition of the uppermost and lowermost AlGaInP barrier layers 113 of the active region stacked structure 112 is greater than the Al composition of the AlGaInP barrier layers 113 in other layers of the active region stacked structure 112. That is, the Al composition of the uppermost and lowermost AlGaInP barrier layers 113 of the active region stacked structure 112 is greater than the Al composition of the lower confinement layer 110, the lower waveguide layer 111, the upper waveguide layer 115, and the upper confinement layer 116, and is also greater than the Al composition of the other layers. The Al composition of the AlGaInP barrier layer 113 is controlled so that, during the subsequent quantum well doping process, not only is the doping induced by impurities or point defects prevented from crossing the active region stacked structure 112 into the lower confinement layer 110, the lower waveguide layer 111, the upper waveguide layer 115, and the upper confinement layer 116, but the doping range induced by impurities or point defects is also precisely controlled to be limited to the region between the uppermost and lowermost AlGaInP barrier layers 113 of the active region stacked structure 112, thereby enabling precise control of the blue shift range of the laser.

[0050] As another preferred example, the Al composition content of the uppermost and lowermost AlGaInP barrier layers 113 of the active region stacked structure 112 is the same.

[0051] As another preferred example, the thickness of the AlGaInP barrier layers 113 in the uppermost and lowermost layers of the active region stacked structure 112 is less than the thickness of the AlGaInP barrier layers 113 in the other layers of the active region stacked structure 112, so as to improve the crystal quality of the entire epitaxial structure. As a specific example, the thickness of the AlGaInP barrier layers 113 in the uppermost and lowermost layers of the active region stacked structure 112 is 2nm to 3nm.

[0052] As an example, the lower confinement layer 110 is selected as an AlInP lower confinement layer, the lower waveguide layer 111 is selected as an AlGaInP lower waveguide layer, the upper waveguide layer 115 is selected as an AlGaInP upper waveguide layer, and the upper confinement layer 116 is selected as an AlInP upper confinement layer.

[0053] As an example, the Al in the active region stacked structure 112 x Ga y In z The number of layers in the P-quantum well 114 is set according to actual needs. For example... Figure 2 Set as a layer Al x Ga y In z P quantum well layer 114, at which point the Al x Ga y In z The AlGaInP barrier layers 113 on both sides of the P quantum well layer 114 are the uppermost and lowermost AlGaInP barrier layers 113 of the active region stacked structure 112; as Figure 3 The middle is set as two layers of Al x Ga y In z P quantum well layer 114; such as Figure 4 The middle is set as several layers of Al x Ga y In z P-quantum well layer 114.

[0054] like Figure 5 and Figure 6 As shown, step S3 is then performed, in which a patterned mask layer 12 is formed on the epitaxial stacked structure 11, and the patterned mask layer 12 exposes the non-absorption window region 13.

[0055] Specifically: a mask layer 12 is first formed on the epitaxial stacked structure 11; then, the mask layer 12 is patterned using a photolithography etching process to form a patterned mask layer 12. The material of the mask layer 12 is selected to be a mask material that can block Zn diffusion into the epitaxial stacked structure 11, such as a silicon oxide mask layer or a silicon nitride mask layer.

[0056] like Figure 5 and Figure 6 As shown, the final step S4 is to perform Zn diffusion on the epitaxial stacked structure 11 based on the patterned mask layer 12 and then anneal it to achieve quantum well hybridization in the non-absorption window region 13.

[0057] As a preferred example, the epitaxial stack structure 11 is epitaxially grown using MOCVD, and Zn diffusion is simultaneously performed on the epitaxial stack structure 11 using MOCVD. This in-situ processing method eliminates the need for an additional, expensive ultra-high vacuum dissociation coating system, significantly reducing equipment investment and production costs. Furthermore, the precursor source for Zn diffusion in the epitaxial stack structure 11 using MOCVD is selected as dimethylzinc, and the protective gas is selected as arsine.

[0058] The concentration of Zn diffusion is selected based on the actual required blue shift range, and no excessive restrictions are imposed here.

[0059] As an example, after Zn diffusion and annealing in step S4, the chip manufacturing process also includes standard wafer manufacturing processes, such as removing the wafer from the MOCVD chamber, removing the surface-patterned mask layer 12 by wet etching (e.g., hydrofluoric acid), and then performing electrode preparation, cleaving, and packaging processes.

[0060] In this embodiment, the non-absorption window of a 650nm laser with a target blue shift of 30nm is used as an example for verification. Specifically: N-type GaAs (15° offset) is selected as the semiconductor substrate 10; the epitaxial stacked structure 11 is selected as an AlInP lower confinement layer 110, an AlGaInP lower waveguide layer 111, an AlGaInP upper waveguide layer 115, and an AlInP upper confinement layer 116; the active region stacked structure 112 is selected as follows... Figure 2 The epitaxial stack consists of a GaInP quantum well layer 114 and two AlGaInP barrier layers 113, with the GaInP quantum well layer 114 having a thickness of 6 nm and the AlGaInP barrier layers 113 having a thickness of 3 nm. The Al composition is 0.8 for both layers. After the epitaxial stack structure is grown, a patterned mask layer 12 is formed on the stack structure. High-temperature diffusion is performed in an MOCVD chamber using dimethyl zinc as the dopant source under an arsine atmosphere. After diffusion, low-temperature annealing is performed to repair the diffused crystal. After annealing, the wafer is removed, and the patterned mask layer is removed using wet etching. The wafer then enters the standard chip manufacturing process, including electrode fabrication, cleaving, and packaging. The diffusion region is characterized using photoluminescence spectroscopy and atomic force microscopy to verify the blue shift effect of the bandgap and the crystal quality.

[0061] like Figure 7 and Figure 9As shown, the photoluminescence spectrum and atomic force microscopy results of the diffusion region before Zn diffusion annealing are presented. The peak wavelength of PL is 648.5 nm, the full width at half maximum (FWHM) is 19.1 nm, and the surface roughness Rq of the epitaxial wafer is 2.6 nm.

[0062] like Figure 8 and Figure 10 As shown, the photoluminescence spectrum and atomic force microscopy results of the diffusion region after Zn diffusion annealing are obtained. The peak wavelength of PL is 616.7 nm, the full width at half maximum (FWHM) is 25.7 nm, and the blue shift is 31.8 nm. No significant broadening was observed. The surface roughness Rq of the epitaxial wafer is 2.3 nm, and the crystal quality has not deteriorated.

[0063] The results above show that this embodiment successfully formed a non-absorption window with a significantly increased band gap in the cavity surface region without introducing additional crystal defects, thus meeting the application requirements.

[0064] Based on this, this embodiment also provides a semiconductor laser based on a quantum well hybrid structure, which is prepared using the fabrication method of the semiconductor laser based on the quantum well hybrid structure in this embodiment.

[0065] In summary, this invention provides a semiconductor laser based on a quantum well hybrid structure and its fabrication method. This is achieved by designing an active region stacked structure in the epitaxial layered structure consisting of an AlGaInP barrier layer and an Al... x Ga y In z AlgaInP quantum well layers are alternately stacked, and the uppermost and lowermost layers of the active region stacked structure are AlGaInP barrier layers. Furthermore, the Al composition of the uppermost and lowermost AlGaInP barrier layers in the active region stacked structure is greater than that of the lower confinement layer, lower waveguide layer, upper waveguide layer, and upper confinement layer, making them the material layers with the highest Al composition. Therefore, during subsequent Zn diffusion and annealing in the non-absorption window region, Zn atoms diffuse in from the mask layer opening region (i.e., the non-absorption window region) into the Al... x Ga y In z The high concentration of group III vacancies in the P quantum well layer region greatly enhances the interdiffusion of In, Ga, and Al atoms, resulting in quantum well hybridization. This is because the Al composition of the AlGaInP barrier layer is relatively high compared to Al... x Ga y In z The p-quantum well layer is higher, thus possessing a higher atomic diffusion activation energy. Impurity or point defect-induced mixing first occurs in low-Al composition Al. x Ga y In zThe mixing process occurs rapidly within the P-quantum well layer, achieving a blue shift in the laser wavelength. When the mixing front advances to the uppermost and lowermost AlGaInP barrier layers of the active region stacked structure with the highest Al composition, the atomic diffusion rate drops sharply, the mixing process is strongly suppressed, automatically decelerates, and tends to stop. This ultimately "locks" the blue shift within the range determined by the uppermost and lowermost AlGaInP barrier layers of the active region stacked structure, making it insensitive to minute changes in annealing time. Thus, this band structure design achieves a "self-stopping" effect for active layer mixing, reducing the stringent requirements for precise control of annealing temperature and time, and improving production yield. Furthermore, the fabrication method of this invention allows for parallel processing of the entire wafer, with a simple process flow that seamlessly integrates with existing chip manufacturing processes, making it suitable for large-scale industrial manufacturing. Therefore, this invention effectively overcomes the various shortcomings of existing technologies and has high industrial applicability.

[0066] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for fabricating a semiconductor laser based on a quantum well intermixed structure, characterized in that, The preparation method comprises the following steps: providing a semiconductor substrate; epitaxially growing an epitaxial stack structure on the semiconductor substrate, the epitaxial stack structure comprising in sequence: a lower confining layer, a lower waveguide layer, an active region stack structure, an upper waveguide layer, an upper confining layer and an ohmic contact layer; wherein the lower confining layer, the lower waveguide layer, the upper waveguide layer and the upper confining layer are all Al-containing material layers, the active region stack structure is formed by alternately stacking AlGaInP barrier layers and Al x Ga y In z P quantum well layers, x+y+z = 1, 0≤x<1, and the uppermost layer and the lowermost layer of the active region stack structure are both the AlGaInP barrier layers, and the Al composition of the AlGaInP barrier layers of the uppermost layer and the lowermost layer of the active region stack structure are both greater than the Al composition of the lower confining layer, the lower waveguide layer, the upper waveguide layer and the upper confining layer; forming a patterned mask layer on the epitaxial stack structure, the patterned mask layer exposing a non-absorption window region; annealing after Zn diffusion based on the patterned mask layer to achieve quantum well intermixing in the non-absorption window region.

2. The method of claim 1, wherein the method further comprises: forming a quantum well intermixing structure on the active region. The Al component of the AlGaInP barrier layer of the uppermost and lowermost layers of the active region stack structure is greater than the Al component of the AlGaInP barrier layer of other layers in the active region stack structure.

3. The method of claim 1 or 2, wherein the method further comprises: forming a quantum well intermixing structure in the active region of the semiconductor laser. The Al component of the AlGaInP barrier layer of the uppermost and lowermost layers of the active region stack structure is the same.

4. The method of claim 1 or 2, wherein the method further comprises: forming a quantum well intermixing structure in the active region of the semiconductor laser. The thickness of the AlGaInP barrier layer of the uppermost and lowermost layers of the active region stack structure is less than the thickness of the AlGaInP barrier layer of other layers in the active region stack structure.

5. The method of claim 4, wherein the method further comprises: The thickness of the AlGaInP barrier layer of the uppermost and lowermost layers of the active region stack structure is 2-3 nm.

6. The method of claim 1, wherein the method further comprises: The lower confinement layer is an AlInP lower confinement layer, the lower waveguide layer is an AlGaInP lower waveguide layer, the upper waveguide layer is an AlGaInP upper waveguide layer, and the upper confinement layer is an AlInP upper confinement layer.

7. The method of claim 1, wherein the method further comprises: The semiconductor substrate is an N-type GaAs substrate.

8. The method of claim 1, wherein the method further comprises: The epitaxial stack structure is epitaxially grown by an MOCVD process, and the epitaxial stack structure is subjected to Zn diffusion by an MOCVD process.

9. The method of claim 8, wherein the method further comprises: The precursor source for Zn diffusion of the epitaxial stack structure by an MOCVD process is dimethyl zinc, and the protective gas is arsine.

10. A semiconductor laser based on a quantum well intermixed structure, characterized by The semiconductor laser based on the quantum well intermixing structure is prepared by the preparation method of any one of claims 1-9.

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