Semiconductor laser element, method for manufacturing the same, and electronic device

Abstract

The application relates to the technical field of semiconductor laser elements, in particular to a semiconductor laser element, a preparation method thereof and an electronic device, wherein the semiconductor laser element comprises a semiconductor base and a protective film; the semiconductor base has a light-emitting end and a reflecting end; the protective film is arranged at the light-emitting end and / or the reflecting end and comprises a first dielectric layer and a second dielectric layer arranged in sequence; the material of the first dielectric layer comprises aluminum oxynitride, the oxygen content of the first dielectric layer is less than or equal to 40 wt%; the material of the second dielectric layer comprises silicon oxynitride; and the oxygen content of the second dielectric layer is less than that of the first dielectric layer. In the semiconductor laser element, the refractive index of the second dielectric layer is not prone to fluctuation caused by water vapor in a preparation cavity during the preparation process of the second dielectric layer; and the oxygen in the second dielectric layer is not prone to transfer to the first dielectric layer during the aging process of the semiconductor laser element, so that the chemical stability of the protective film can be effectively improved, and the reliability life of the semiconductor laser element can be effectively improved.

Description

Technical Field

[0001] This invention relates to the field of semiconductor laser element technology, and more particularly to semiconductor laser elements, their fabrication methods, and electronic devices. Background Technology

[0002] Semiconductor laser devices possess advantages such as small size, light weight, long lifespan, and high efficiency, and are currently widely used in optical communication, optical pumping, optical storage, and laser displays. Catastrophic Optical Damage (COD) is the most significant failure mode at the emitting and reflecting ends of semiconductor laser devices. The principle is as follows: When a semiconductor laser device is operating, impurities and defects at the device's end face absorb light, causing a localized temperature increase. This temperature rise simultaneously narrows the bandgap of the semiconductor material at the end face and worsens the impurities and defects, further increasing light absorption. This vicious cycle eventually leads to an avalanche effect, causing the end face material to melt and the device to crack due to the continuous rise in temperature. By applying an AR (anti-reflective coating) at the front end (emitting end) and an HR (high-reflective coating) at the rear end (reflecting end) of the semiconductor laser device, optical catastrophic damage at the end face can be effectively prevented, improving the reliability and lifespan of the semiconductor laser device.

[0003] However, there is still considerable room for improvement in the chemical stability of the end-face film structure of existing semiconductor lasers, and the long-term reliability and lifespan of semiconductor laser components still need to be further improved. Summary of the Invention

[0004] This application provides a semiconductor laser element and its fabrication method, as well as an electronic device, which aims to improve the chemical stability of the film structure at the light-emitting end or the reflective end of the semiconductor laser element and enhance the long-term reliability and lifespan of the semiconductor laser element.

[0005] In a first aspect, embodiments of this application provide a semiconductor laser element, including:

[0006] A semiconductor substrate having a light-emitting end and a reflective end disposed opposite to each other;

[0007] A protective film is disposed at the light-emitting end and / or the reflective end. The protective film includes a first dielectric layer and a second dielectric layer stacked sequentially from the inside to the outside. The material of the first dielectric layer includes aluminum oxynitride, and the oxygen content of the first dielectric layer is ≤40wt%. The material of the second dielectric layer includes silicon oxynitride, and the oxygen content of the second dielectric layer is less than that of the first dielectric layer.

[0008] In the semiconductor laser element of the first aspect of this application, the first dielectric layer includes aluminum oxynitride. Aluminum oxynitride has excellent crystallinity and a large bandgap, making it less prone to optical catastrophic events at the interface, which can effectively improve the long-term reliability of the semiconductor laser element. As the oxygen content of aluminum oxynitride in the first dielectric layer increases, the first dielectric layer will experience a decrease in refractive index, a decrease in stress, and a deterioration in film quality. The decrease in stress is beneficial to improving the stability of the film layer, but the deterioration in film quality will reduce the reliability of the film layer. Therefore, by controlling the oxygen content of the first dielectric layer to ≤40wt%, the stress and film quality of the first dielectric layer can be better balanced, thereby further improving the long-term reliability and lifespan of the semiconductor laser element. The second dielectric layer prevents the first dielectric layer from contacting external moisture, thus avoiding oxidation of the first dielectric layer. The second dielectric layer is made of silicon oxynitride, a material with a simple fabrication process that is less susceptible to refractive index fluctuations due to moisture within the fabrication chamber. Furthermore, because the oxygen content of the second dielectric layer is lower than that of the first dielectric layer, the amount of oxygen transferred from the second dielectric layer to the first dielectric layer is limited during the aging process of the semiconductor laser element, effectively ensuring the chemical stability of the protective film. In summary, the protective film of this semiconductor laser element exhibits excellent chemical stability, effectively improving the long-term reliability and lifespan of the semiconductor laser element.

[0009] In some embodiments, the oxygen content of the second dielectric layer is M, where 5wt% ≤ M < 40wt%. Within this range, the second dielectric layer can protect the first dielectric layer, balance the film stress, and more effectively prevent fluctuations in the refractive index caused by oxygen during the film formation process of the second dielectric layer.

[0010] Secondly, embodiments of this application also propose a semiconductor laser element, comprising:

[0011] A semiconductor substrate having a light-emitting end and a reflective end disposed opposite to each other;

[0012] A protective film is disposed at the light-emitting end and / or the reflective end. The protective film includes a first dielectric layer and a second dielectric layer stacked sequentially from the inside to the outside. The material of the first dielectric layer includes aluminum nitride, and the material of the second dielectric layer includes silicon oxynitride. The oxygen content of the second dielectric layer is ≤30wt%.

[0013] In the semiconductor laser element of the second aspect of this application, the first dielectric layer comprises aluminum nitride. Aluminum nitride has excellent crystallinity and a large bandgap, making it less prone to optical catastrophic events at the interface, thus effectively improving the long-term reliability of the semiconductor laser element. The second dielectric layer prevents the first dielectric layer from contacting external moisture, avoiding oxidation of the first dielectric layer by external moisture. The material of the second dielectric layer comprises silicon oxynitride. The fabrication process of silicon oxynitride thin film is simple, and the refractive index is not easily affected by moisture in the fabrication cavity during the fabrication process. Furthermore, since the oxygen content of the second dielectric layer is ≤30wt%, the amount of oxygen transferred from the second dielectric layer to the first dielectric layer is limited during the aging process of the semiconductor laser element, effectively ensuring the chemical stability of the protective film. In summary, the protective film of this semiconductor laser element has excellent chemical stability, effectively improving the long-term reliability and lifespan of the semiconductor laser element.

[0014] In some embodiments, the oxygen content of the second dielectric layer is 5 wt% to 30 wt%. Within this range, the second dielectric layer can protect the first dielectric layer, balance the film stress, and more effectively prevent fluctuations in the refractive index caused by oxygen during the film formation process of the second dielectric layer.

[0015] In some embodiments, the thickness of the first dielectric layer is 10 nm to 300 nm. By controlling the thickness of the first dielectric layer within this range, it is beneficial to improve the mechanical properties of the first dielectric layer and avoid the occurrence of film cracking.

[0016] In some embodiments, the thickness of the second dielectric layer is 3 nm to 300 nm. Controlling the thickness of the second dielectric layer within this range is beneficial for protecting the first dielectric layer and balancing the stress of the film layer.

[0017] In some embodiments, the first dielectric layer has a C-axis or M-axis crystal orientation. This configuration not only enhances the bonding between the protective film and the semiconductor substrate, but also helps reduce crystal defects within the protective film, thereby increasing the threshold for optical catastrophic events. Compared to the C-axis crystal orientation, the M-axis crystal orientation of the first dielectric layer bonds more tightly to the semiconductor substrate and is less prone to optical catastrophic events.

[0018] In some embodiments, the silicon oxynitride crystal structure in the second dielectric layer is polycrystalline or amorphous. Amorphous or polycrystalline structures can avoid the light scattering effect of crystal boundaries, thereby improving the optical quality of the protective film.

[0019] In some embodiments, the protective film further includes a third dielectric layer disposed on the side of the second dielectric layer facing away from the first dielectric layer. By providing the third dielectric layer, the reflectivity of the protective film can be adjusted to an appropriate range to meet practical application requirements.

[0020] In some embodiments, the protective film disposed at the light-emitting end is a first protective film, which includes n layers of the third dielectric layer, where n is a positive integer, 2≤n≤6, and the material of the n third dielectric layers independently includes one or more of oxides, nitrides, and oxynitrides. By setting the number of third dielectric layers to 2 to 6, it is beneficial to adjust the reflectivity of the first protective film to a suitable range.

[0021] In some embodiments, the reflectivity of the first protective film is 10% to 30% in the 400nm to 550nm wavelength range.

[0022] In some embodiments, the protective film disposed at the reflective end is a second protective film, the second protective film comprising m layers of the third dielectric layer, where m is a positive integer, m≥10, and the material of the m layers of the third dielectric layer independently includes one or more of oxides, nitrides, and oxynitrides. By making the number of third dielectric layers ≥10, it is beneficial to adjust the reflectivity of the second protective film to a suitable range.

[0023] In some embodiments, the reflectivity of the second protective film is ≥98% in the 400nm to 550nm wavelength range.

[0024] In some embodiments, the oxide includes one or more of aluminum oxide, silicon oxide, tantalum oxide, titanium oxide, hafnium oxide, zirconium oxide, niobium oxide, and yttrium oxide; and / or,

[0025] The nitrogen oxides include one or more of aluminum oxynitride, silicon oxynitride, tantalum oxynitride, and titanium oxynitride; and / or,

[0026] The nitride film includes one or more of silicon nitride, tantalum nitride, titanium nitride, and aluminum nitride.

[0027] In some embodiments, the thickness of the third dielectric layer is 150 nm to 400 nm. Within this range, it is advantageous to adjust the reflectivity of the protective film to a suitable range.

[0028] In some embodiments, the semiconductor substrate includes a gallium nitride (GaN) substrate and an epitaxial layer grown on the surface of the GaN substrate. The orientation of the surface of the GaN substrate facing the epitaxial layer is 0°–15° tilted from the C-axis to the M-axis. A certain C-axis tilt angle towards the M-axis can provide smooth and orderly steps on the surface of the GaN substrate, enabling the epitaxial layer to achieve stable step flow growth and resulting in better crystal quality. Controlling the tilt angle within 15° can avoid step aggregation, making it easier to control the crystal orientation of the epitaxial layer during growth. The epitaxial layer has high surface flatness and a clear quantum hydrazine interface, which is beneficial to improving internal quantum efficiency.

[0029] Thirdly, embodiments of this application also propose a method for fabricating a semiconductor laser element, comprising the following steps:

[0030] A semiconductor substrate is provided, and a first dielectric layer is disposed at the light-emitting end and / or the reflective end of the semiconductor substrate. The material of the first dielectric layer includes aluminum oxynitride, and the oxygen content of the first dielectric layer is ≤40wt%.

[0031] A second dielectric layer is disposed on the surface of the first dielectric layer, the material of the second dielectric layer including silicon oxynitride, and the oxygen content of the second dielectric layer is less than the oxygen content of the first dielectric layer.

[0032] Thirdly, embodiments of this application also propose a method for fabricating a semiconductor laser element, comprising the following steps:

[0033] A semiconductor substrate is provided, and a first dielectric layer is disposed at the light-emitting end and / or the reflective end of the semiconductor substrate, wherein the material of the first dielectric layer includes aluminum nitride;

[0034] A second dielectric layer is disposed on the surface of the first dielectric layer, the material of the second dielectric layer including silicon oxynitride, and the oxygen content of the second dielectric layer is ≤30wt%.

[0035] Fourthly, embodiments of this application also propose an electronic device comprising a semiconductor laser element as described in the first or second aspect, or comprising a semiconductor laser element prepared using the preparation method described in the third or third aspect. Attached Figure Description

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

[0037] Figure 1 This is a schematic diagram of the structure of the semiconductor laser element in one embodiment of this application;

[0038] Figure 2 for Figure 1 A schematic diagram of the structure of the first protective film in the middle;

[0039] Figure 3 for Figure 1 A schematic diagram of the structure of the second protective membrane.

[0040] Figure label:

[0041] 100. Semiconductor laser components;

[0042] 110. Semiconductor substrate;

[0043] 120. First protective film; 121. First dielectric layer; 122. Second dielectric layer; 123. Third dielectric layer;

[0044] 130. Second protective film (protective film). Detailed Implementation

[0045] To better understand the technical solution of the present invention, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0046] It should be understood that the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0047] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” as used in the embodiments of this invention and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0048] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0049] This application proposes an electronic device.

[0050] In this embodiment, the electronic device can be a consumer electronics terminal product, a home electronics product, an in-vehicle electronics product, or a communication electronics product, etc.

[0051] Specifically, electronic devices can be laser devices for industrial processing, household lighting devices, laser headlights, laser projectors, laser TVs, and vehicle-mounted HUDs (Head-up Display systems), etc.

[0052] In this embodiment of the application, the electronic device includes at least one semiconductor laser element.

[0053] Semiconductor laser devices possess advantages such as small size, light weight, long lifespan, and high efficiency. Catastrophic optical damage (COD) is the most significant failure mode at the emitting and reflecting ends of semiconductor laser devices. The principle is as follows: During operation, impurities and defects at the end face of the semiconductor laser device absorb light, causing a localized temperature increase. This temperature rise leads to a narrowing of the band gap in the semiconductor material at the end face and worsens the impurities and defects, further increasing light absorption. This vicious cycle eventually results in an avalanche effect, causing the end face temperature to continue rising until the end face material melts and the end face cracks. By applying an AR (anti-reflective coating) at the front end (emitting end) and an HR (high-reflective coating) at the rear end (reflecting end) of the semiconductor laser device, optical catastrophic damage at the end face can be effectively prevented, improving the reliability and lifespan of the semiconductor laser device.

[0054] However, there is still considerable room for improvement in the chemical stability of the end-face film structure of existing semiconductor laser devices, and the reliability and lifespan of semiconductor laser devices still need to be further improved.

[0055] Specifically, in some AR / HR film structures, the first layer is made of AlON and the second layer is made of SiN. This film structure has the following problem: the SiN film is highly susceptible to moisture in the fabrication chamber during the preparation process, which can cause fluctuations in the refractive index, thereby affecting the overall reflectivity of the film structure and ultimately impacting the reliability and yield of the semiconductor laser device.

[0056] In some other AR / HR film structures, the first layer is made of AlN and the second layer is made of SiO2. This film structure has the following problem: AlN and SiO2 undergo a solid-state reaction during the chip aging process of the semiconductor laser device, which leads to changes in the material composition and density of the film structure, thereby affecting the reliability and lifespan of the semiconductor laser device.

[0057] Based on this, in a first aspect, this application proposes a semiconductor laser element to improve the chemical stability of the film structure at the light-emitting end or the reflective end of the semiconductor laser element, thereby improving the long-term reliability and lifespan of the semiconductor laser element.

[0058] Please see Figure 1 , Figure 2 and Figure 3In this embodiment of the application, the semiconductor laser element 100 includes a semiconductor substrate 110 and a protective film 120 / 130. The semiconductor substrate 110 has a light-emitting end and a reflective end disposed opposite to each other. The protective film 120 / 130 is disposed at the light-emitting end and / or the reflective end. The protective film 120 / 130 includes a first dielectric layer 121 and a second dielectric layer 122 stacked sequentially from the inside to the outside. The material of the first dielectric layer 121 includes aluminum oxynitride, and the oxygen content of the first dielectric layer 121 is ≤40wt%. The material of the second dielectric layer 122 includes silicon oxynitride, and the oxygen content of the second dielectric layer 122 is less than the oxygen content of the first dielectric layer 121.

[0059] In the semiconductor laser element 100 of the first aspect of this application, the first dielectric layer 121 includes aluminum oxynitride. Aluminum oxynitride has excellent crystallinity and a large bandgap, making it less prone to optical catastrophic events at the interface, which can effectively improve the long-term reliability of the semiconductor laser element 100. As the oxygen content of aluminum oxynitride in the first dielectric layer 121 increases, the first dielectric layer 121 will experience a decrease in refractive index, a decrease in stress, and a deterioration in film quality. The decrease in stress is beneficial to improving the stability of the film layer, but the deterioration in film quality will reduce the reliability of the film layer. Therefore, by controlling the oxygen content of the first dielectric layer 121 to ≤40wt%, the stress and film quality of the first dielectric layer 121 can be better balanced, thereby further improving the reliability and lifespan of the semiconductor laser element 100. The second dielectric layer 122 prevents the first dielectric layer 121 from contacting external moisture, thus avoiding oxidation of the first dielectric layer 121. The material of the second dielectric layer 122 includes silicon oxynitride. The fabrication process of silicon oxynitride thin film is simple, and its refractive index is not easily affected by moisture in the fabrication chamber during the fabrication process. Furthermore, since the oxygen content of the second dielectric layer 122 is less than that of the first dielectric layer 121, the amount of oxygen transferred from the second dielectric layer 122 to the first dielectric layer 121 is limited during the aging process of the semiconductor laser element 100, effectively ensuring the chemical stability of the protective films 120 / 130. In summary, the protective films 120 / 130 of the semiconductor laser element 100 have excellent chemical stability, which can effectively improve the long-term reliability and lifespan of the semiconductor laser element 100.

[0060] In some embodiments, the oxygen content of the second dielectric layer 122 is M, where 5wt% ≤ M < 40wt%. Within this range, the second dielectric layer 122 can protect the first dielectric layer 121, balance the film stress, and more effectively prevent fluctuations in the refractive index caused by oxygen during the film formation process of the second dielectric layer 122.

[0061] Secondly, this application also proposes another semiconductor laser element 100.

[0062] Please see Figure 1 , Figure 2 and Figure 3 In this embodiment of the application, the semiconductor laser element 100 includes a semiconductor substrate 110 and a protective film 120 / 130. The semiconductor substrate 110 has a light-emitting end and a reflective end. The protective film 120 / 130 is disposed at the light-emitting end and / or the reflective end. The protective film 120 / 130 includes a first dielectric layer 121 and a second dielectric layer 122 stacked sequentially from the inside to the outside. The material of the first dielectric layer 121 includes aluminum nitride, and the material of the second dielectric layer 122 includes silicon oxynitride. The oxygen content of the second dielectric layer 122 is ≤30wt%.

[0063] In the semiconductor laser element 100 of the second aspect of this application, the first dielectric layer 121 comprises aluminum nitride. Aluminum nitride has excellent crystallinity and a large bandgap, making it less prone to optical catastrophic events at the interface, thus effectively improving the long-term reliability of the semiconductor laser element 100. The second dielectric layer 122 prevents the first dielectric layer 121 from contacting external moisture, avoiding oxidation of the first dielectric layer 121 by external moisture. The material of the second dielectric layer 122 comprises silicon oxynitride. The preparation process of silicon oxynitride thin film is simple, and the refractive index is not easily affected by moisture in the preparation cavity during the preparation process. Furthermore, since the oxygen content of the second dielectric layer 122 is ≤30wt%, the amount of oxygen transferred from the second dielectric layer 122 to the first dielectric layer 121 is limited during the aging process of the semiconductor laser element 100, effectively ensuring the chemical stability of the protective films 120 / 130. In summary, the protective films 120 / 130 of the semiconductor laser element 100 have excellent chemical stability, effectively improving the long-term reliability and lifespan of the semiconductor laser element 100.

[0064] In some embodiments, the oxygen content of the second dielectric layer 122 is 5 wt% to 30 wt%, specifically 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 20 wt%, 30 wt%, or any value between them. Within this range, the second dielectric layer 122 can both protect the first dielectric layer 121 and balance the film stress, and can more effectively prevent fluctuations in the refractive index caused by oxygen during the film formation process of the second dielectric layer 122.

[0065] The semiconductor laser element 100 described in the first and second aspects above will be further described below.

[0066] In this embodiment, the oxygen content of the first dielectric layer 121 and the oxygen content of the second dielectric layer 122 can be accurately analyzed using equipment such as EDS spectrometer, X-ray photoelectron spectrometer (XPS), and secondary ion mass spectrometer (SIMS).

[0067] In some embodiments, the semiconductor laser element 100 is subjected to long-term reliability testing, and the long-term reliability lifespan of the semiconductor laser element 100 is ≥20,000 hours. The long-term reliability testing method is as follows: after the semiconductor laser element 100 is packaged in TO (Transistor Outline) form, it is continuously powered on and tested in a test environment of 60°C and 3A current to test the output power stability of the semiconductor laser element 100. The equivalent long-term aging lifespan (long-term reliability lifespan) of the semiconductor laser element 100 is obtained by analyzing its output power stability.

[0068] In some embodiments, the thickness of the second dielectric layer 122 is 3 nm to 300 nm, specifically 3 nm, 50 nm, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, or any value between them. By controlling the thickness of the second dielectric layer 122 within this range, it is beneficial to protect the first dielectric layer 121 and balance the stress of the film layer.

[0069] In some embodiments, the silicon oxynitride crystal structure in the second dielectric layer 122 is polycrystalline or amorphous. The amorphous or polycrystalline structure can avoid the scattering effect of light by the crystal boundary, thereby improving the optical quality of the protective film 120 / 130.

[0070] In some embodiments, the thickness of the first dielectric layer 121 is 10 nm to 300 nm, specifically 10 nm, 50 nm, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, or any value between them. By controlling the thickness of the first dielectric layer 121 within this range, it is beneficial to improve the mechanical properties of the first dielectric layer 121 and avoid the occurrence of film cracking.

[0071] In some embodiments, the first dielectric layer 121 has a C-axis or M-axis crystal orientation. This arrangement not only enhances the bonding between the protective film 120 / 130 and the semiconductor substrate 110, but also helps to reduce crystal defects within the protective film 120 / 130, thereby increasing the threshold for optical catastrophic events.

[0072] Please see Figure 2 or Figure 3 In some embodiments, the protective film 120 / 130 further includes a third dielectric layer 123. By providing the third dielectric layer 123, the reflectivity of the protective film 120 / 130 can be adjusted to an appropriate range to meet practical application requirements.

[0073] In some embodiments, the oxide includes one or more of other commonly used dielectric layer materials in the art, such as aluminum oxide, silicon oxide, tantalum oxide, titanium oxide, hafnium oxide, zirconium oxide, niobium oxide, and yttrium oxide.

[0074] In some embodiments, nitrogen oxides include one or more of other commonly used dielectric layer materials in the art, such as aluminum oxynitride, silicon oxynitride, tantalum oxynitride, and titanium oxynitride.

[0075] In some embodiments, the nitride film includes one or more of other commonly used dielectric layer materials in the art, such as silicon nitride, tantalum nitride, titanium nitride, and aluminum nitride.

[0076] In some embodiments, the thickness of the third dielectric layer 123 is 50nm to 150nm, specifically 50nm, 80nm, 100nm, 120nm, 150nm or any value between them.

[0077] Understandably, the protective film 120 / 130 in this embodiment may be disposed on only one of the light-emitting end or the reflective end of the semiconductor substrate 110, while other highly stable film structures may be disposed on the other. Of course, the protective film 120 / 130 in this embodiment may also be disposed on both the light-emitting end and the reflective end of the semiconductor substrate 110.

[0078] Please see Figure 2 In some embodiments, a protective film, referred to as a first protective film 120, is provided at the light-emitting end of the semiconductor substrate 110. The reflectivity of the first protective film 120 in the 400nm-550nm wavelength range is 10%-30%, specifically 10%, 12%, 14%, 16%, 18%, 30%, or any value between them. If the reflectivity of the first protective film 120 is too low, it may affect the emitted light power; if the reflectivity of the first protective film 120 is too high, it may lead to excessive power in the resonant cavity of the semiconductor substrate 110, causing degradation of the epitaxial layer material of the semiconductor substrate 110.

[0079] In some embodiments, the first protective film 120 includes n third dielectric layers 123, where n is a positive integer, 2≤n≤6, that is, the total number of film layers in the first protective film 120 is 4 to 8, and the materials of the n third dielectric layers 123 can be the same or different. By setting the number of third dielectric layers 123 to 2 to 6, it is beneficial to adjust the reflectivity of the first protective film 120 to a suitable range.

[0080] In some embodiments, the total thickness of the n third dielectric layers 123 in the first protective film 120 is 100 nm to 400 nm, specifically 100 nm, 150 nm, 200 nm, 300 nm, 400 nm, or any value between them. By controlling the total thickness of the third dielectric layers 123 within this range, it is beneficial to adjust the reflectivity of the first protective film 120 to a suitable range.

[0081] Please see Figure 3In some embodiments, a protective film is provided at the reflective end of the semiconductor substrate 110, referred to as the second protective film 130, and the reflectivity of the second protective film 130 is ≥98% in the 400nm to 550nm wavelength range. If the reflectivity of the second protective film 130 is too low, it will affect the output light power.

[0082] Please see Figure 3 In some embodiments, the second protective film 130 includes m third dielectric layers 123, where m is a positive integer and m ≥ 10, meaning the total number of film layers in the second protective film 130 is ≥ 12. The materials of the m third dielectric layers 123 can be the same or different. By making the number of third dielectric layers 123 ≥ 16, it is beneficial to adjust the reflectivity of the second protective film 130 to a suitable range.

[0083] In some embodiments, the total thickness of the m-th third dielectric layer 123 in the second protective film is 1500 nm to 3000 nm, specifically 1500 nm, 1800 nm, 2000 nm, 2500 nm, 3000 nm, or any value between them. By controlling the total thickness of the third dielectric layer 123 within this range, it is beneficial to adjust the reflectivity of the second protective film 130 to a suitable range.

[0084] In this embodiment, the semiconductor laser element 100 can be a gallium nitride-based semiconductor laser element 100, an indium phosphide-based semiconductor laser element 100, a gallium arsenide-based semiconductor laser element 100, etc.

[0085] In some embodiments, the semiconductor laser element 100 is a gallium nitride-based semiconductor laser element 100, the semiconductor substrate 110 is a gallium nitride semiconductor substrate 110, and the aluminum oxynitride and aluminum nitride in the first dielectric layer 121 are stress-matched with the gallium nitride semiconductor substrate 110, which is beneficial to improving the long-term reliability of the semiconductor laser.

[0086] The semiconductor substrate 110 of this application embodiment will be further described below, taking gallium nitride-based semiconductor laser element 100 as an example.

[0087] In this embodiment of the application, the semiconductor substrate 110 includes a substrate and an epitaxial layer grown on one side surface of the substrate, wherein the substrate may be a GaN substrate.

[0088] In some embodiments, the substrate is a gallium nitride substrate, and the orientation of the surface of the gallium nitride substrate facing the epitaxial layer is such that the C-axis is tilted towards the M-axis at a rate of 0° to 15°. The specific tilt angle can be 0°, 5°, 10°, 15° or any value between them. The end face of the light-emitting end of the semiconductor substrate 110 (the cleaved end face of the light-emitting direction of the epitaxial layer) extends in a normal direction perpendicular to the C-axis direction of the gallium nitride substrate. Alternatively, the end face of the reflective end of the semiconductor substrate 110 extends in a normal direction perpendicular to the C-axis direction of the gallium nitride substrate.

[0089] A certain C-axis to M-axis offset angle can provide a flat and orderly step on the surface of the gallium nitride substrate, enabling the epitaxial layer to achieve stable step flow growth and improve crystal quality. Controlling the offset angle within 15° can avoid step aggregation, making it easier to control the crystal orientation during epitaxial layer growth. The epitaxial layer has high surface flatness and a clear quantum hydrazine interface, which is beneficial to improving internal quantum efficiency and extending the long-term service life of semiconductor laser devices 100.

[0090] In the above embodiments, the epitaxial layer includes an n-type layer, an n-type confinement layer, an active layer, a p-type confinement layer, and a p-type contact layer, which are disposed sequentially on the substrate surface from near to far.

[0091] In some embodiments, the n-type layer can be a single-layer or multi-layer structure composed of In(x)Al(y)Ga(1-xy)N, where 0≤x / y≤0.3. The n-type GaN layer can be doped with n-type impurities, such as Si or Ge.

[0092] In some embodiments, the doping concentration of n-type impurities in the n-type GaN layer is approximately 5E10. 16 cm -3 ~5E10 19 cm -3 .

[0093] In the above embodiments, the thickness of the n-type GaN layer can be adjusted according to actual application requirements. In one specific embodiment, the thickness of the n-type GaN layer is approximately 0.5 μm to 4 μm, specifically 0.5 μm, 1.5 μm, 2.5 μm, 3.5 μm, 4 μm, or any value between them.

[0094] In the above embodiments, the material of the n-type confinement layer can be AlGaN, AlInGaN, AlGaN / GaN, AlInGaN / GaN superlattice structure, etc.

[0095] In the above embodiments, the thickness of the n-type confinement layer can be adjusted according to actual application requirements. In one specific embodiment, the thickness of the n-type confinement layer is 0.2 μm to 2 μm, specifically 0.2 μm, 0.5 μm, 1 μm, 2 μm or any value between them.

[0096] In the above embodiments, the active layer includes alternating layers of barrier layers and quantum well layers. The material of the quantum well layer can be selected from one or more of InGaN, and the material of the barrier layer can be selected from one or more of GaN, InGaN, AlInGaN, etc.

[0097] In the above embodiments, the number and thickness of the barrier layer and quantum well layer can be adjusted according to actual application requirements. In one specific embodiment, the active layer includes a first barrier layer, a quantum well layer, and a second barrier layer sequentially disposed on the surface of the n-type confinement layer from near to far, wherein the first barrier layer is a heavily doped n-type layer. + - GaN layer, thickness 1nm~15nm; quantum well layer is In(x)Ga(1-x)N well layer with In content x of 0.05~0.35, thickness 1nm~6nm; second barrier layer is undoped GaN or AlGaN / InGaN superlattice, thickness 0.5nm~15nm.

[0098] In the above embodiments, the material of the p-type confinement layer can be AlGaN / GaN superlattice, etc.

[0099] In the above embodiments, the thickness of the p-type confinement layer can be adjusted according to actual application requirements. In one specific embodiment, the thickness of the p-type confinement layer is 1nm to 50nm, specifically 1nm, 5nm, 10nm, 20nm, 50nm, or any value between them.

[0100] In the above embodiments, the thickness of the p-type GaN contact layer can be adjusted according to actual application requirements. In one specific embodiment, the thickness of the p-type GaN contact layer is approximately 1 nm to 50 nm, specifically 1 nm, 5 nm, 10 nm, 20 nm, 50 nm, or any value between them.

[0101] In some embodiments, the epitaxial layer further includes a first waveguide layer disposed between the n-type confinement layer and the active layer, for guiding light waves to propagate in the horizontal direction. The first waveguide layer may consist of one or more layers of lightly doped AlGaN, GaN, InGaN, or other materials; the thickness of the first waveguide layer can be adjusted according to actual application requirements. In one specific embodiment, the thickness of the first waveguide layer is approximately 10 nm to 1500 nm, specifically 10 nm, 20 nm, 50 nm, 100 nm, 200 nm, 500 nm, 1000 nm, 1500 nm, or any value between them.

[0102] In some embodiments, the epitaxial layer further includes a second waveguide layer disposed between the active layer and the p-type confinement layer, for further guiding light waves and balancing carrier distribution. The second waveguide layer may be composed of undoped and p-doped InGaN, GaN, AlGaN, InGaN / GaN superlattice, or other materials. The thickness of the second waveguide layer can be adjusted according to actual application requirements. In one specific embodiment, the thickness of the second waveguide layer is approximately 20nm-1000nm, specifically 20nm, 50nm, 100nm, 500nm, 1000nm, or any value between them.

[0103] In the above embodiments, the semiconductor substrate 110 further includes an n-type electrode and a p-type electrode. The n-type electrode is disposed on the side of the substrate away from the epitaxial layer, and the p-type electrode is disposed on the side of the p-type GaN contact layer away from the p-type confinement layer. The materials of the n-type electrode and the p-type electrode can be independently selected from transparent conductive materials such as ITO, or one or more metals such as palladium, platinum, gold, nickel, and chromium.

[0104] Thirdly, embodiments of this application also provide a method for fabricating a semiconductor laser element 100, which can be used to fabricate the semiconductor laser element 100 described in the first aspect.

[0105] In this embodiment of the application, the method for fabricating the semiconductor laser element 100 includes the following steps:

[0106] A semiconductor substrate 110 is provided, and a first dielectric layer 121 is disposed at the light-emitting end and / or the reflective end of the semiconductor substrate 110. The material of the first dielectric layer 121 includes aluminum oxynitride, and the oxygen content of the first dielectric layer 121 is ≤40wt%.

[0107] A second dielectric layer 122 is disposed on the surface of the first dielectric layer 121. The material of the second dielectric layer 122 includes silicon oxynitride, and the oxygen content of the second dielectric layer 122 is less than the oxygen content of the first dielectric layer 121.

[0108] Fourthly, this application also proposes a method for fabricating a semiconductor laser element 100, which can be used to fabricate the semiconductor laser element 100 described in the second aspect above.

[0109] In this embodiment of the application, the method for fabricating the semiconductor laser element 100 includes the following steps:

[0110] A semiconductor substrate 110 is provided, and a first dielectric layer 121 is disposed at the light-emitting end and / or the reflective end of the semiconductor substrate 110. The material of the first dielectric layer 121 includes aluminum nitride.

[0111] A second dielectric layer 122 is disposed on the surface of the first dielectric layer 121. The material of the second dielectric layer 122 includes silicon oxynitride, and the oxygen content of the second dielectric layer 122 is ≤30wt%.

[0112] The preparation methods of the third aspect and the fourth aspect will be further described below, taking the example that the light-emitting end and the reflective end of the semiconductor substrate 110 are respectively provided with the first dielectric layer 121 and the second dielectric layer 122.

[0113] In some embodiments, the fabrication steps of the semiconductor substrate 110 include:

[0114] Provide a substrate, and grow an epitaxial layer on the substrate;

[0115] A p-type electrode is disposed on the side of the epitaxial layer facing away from the substrate, and an n-type electrode is disposed on the side of the substrate facing away from the epitaxial layer to obtain a semiconductor precursor.

[0116] A semiconductor precursor is cleaved to obtain a semiconductor substrate 110. The semiconductor substrate 110 has a first cleaved end face (light-emitting end face) and a second cleaved end face (reflecting end face) arranged opposite to each other, and a resonator is formed between the first cleaved end face and the second cleaved end face.

[0117] In some embodiments, the method for fabricating the semiconductor laser element 100 further includes the step of:

[0118] At the light-emitting end of the semiconductor substrate 110, n third dielectric layers 123 are disposed on the surface of the second dielectric layer 122. The composite of the first dielectric layer 121, the second dielectric layer 122 and the n third dielectric layers 123 forms a first protective film 120. The reflectivity of the first protective film 120 in the 400nm to 550nm wavelength range is 10% to 30%.

[0119] In some embodiments, the method for fabricating the semiconductor laser element 100 further includes the step of:

[0120] At the reflective end of the semiconductor substrate 110, a third dielectric layer 123 is disposed on the surface of the second dielectric layer 122. The composite of the first dielectric layer 121, the second dielectric layer 122 and the third dielectric layer 123 forms a second protective film. The reflectivity of the second protective film is ≥98% in the 400nm to 550nm wavelength range.

[0121] In some embodiments, the first dielectric layer 121, the second dielectric layer 122, and the third dielectric layer 123 can be prepared using equipment such as magnetron sputtering coating, evaporation coating, or microwave electron cyclotron resonance coating equipment.

[0122] The present invention will be further described below through more specific embodiments.

[0123] Example 1:

[0124] A nitride semiconductor laser element is prepared by the following method:

[0125] A semiconductor substrate is fabricated, comprising a gallium nitride substrate and an epitaxial layer grown on one side surface of the gallium nitride substrate. The orientation of the gallium nitride substrate toward the epitaxial layer is such that the C-axis is tilted toward the M-axis at a 5° angle. The semiconductor substrate has a first cleaving end face (light-emitting end face) and a second cleaving end face (reflecting end face), and a resonant cavity is formed between the first cleaving end face and the second cleaving end face.

[0126] Deposition of the first protective film: A 50 nm thick AlON thin film with an oxygen content of 25 wt% is first deposited on the first cleavage end face of the semiconductor substrate; then a 120 nm thick SiON thin film with an oxygen content of 20 wt% is deposited; finally, a 150 nm thick Al2O3 thin film and a 100 nm thick Ta2O5 thin film are deposited on the outside of the SiON thin film. The reflectivity of the first protective film at a wavelength of 460 nm reaches 22%.

[0127] Deposition of the second protective film: First, a 50 nm thick AlON thin film with an oxygen content of 25 wt% is deposited on the second cleavage end face of the semiconductor substrate; then, a 120 nm thick SiON thin film with an oxygen content of 20 wt% is deposited; finally, a 150 nm thick Al2O3 thin film and a 100 nm thick Ta2O5 thin film are deposited sequentially on the outside of the SiON thin film. Finally, multiple alternating depositions of SiO2 and Ta2O5 films are performed, and the total thickness of the third dielectric layer reaches 1600 nm, ultimately making the reflectivity of the second protective film ≥98% at a wavelength of 460 nm.

[0128] The nitride semiconductor laser element prepared in Example 1 was packaged in TO (Transistor Outline) and then subjected to long-term reliability testing. The final test results showed that its equivalent long-term aging life exceeded 40,000 hours.

[0129] Example 2

[0130] The difference from Example 1 is that:

[0131] In the first protective film deposition step, the AlON film is 300 nm thick and has an oxygen content of 40 wt%; the SiON film is 5 nm thick and has an oxygen content of 30 wt%. Finally, a 50 nm Al2O3 film and a 150 nm Ta2O5 film are deposited on the outside of the SiON film. The reflectivity of the first protective film at a wavelength of 460 nm reaches 10%.

[0132] In the step of depositing the second protective film, the first dielectric layer (first thin film) and the second dielectric layer (second thin film) of the second protective film are consistent with the first dielectric layer (AlON thin film) and the second dielectric layer (SiON thin film) of the first protective film, respectively.

[0133] The nitride semiconductor laser element prepared in Example 2 was packaged and then subjected to long-term reliability testing. The test results showed that its equivalent long-term aging life exceeded 40,000 hours.

[0134] Example 3

[0135] The difference from Example 1 is that:

[0136] The AlON film is 10 nm thick with an oxygen content of 6 wt%; the SiON film is 300 nm thick with an oxygen content of 5 wt%. Finally, a 100 nm Al2O3 film and a 300 nm Ta2O5 film are deposited sequentially on the outside of the SiON film. The reflectivity of the first protective film reaches 30% at a wavelength of 460 nm.

[0137] In the step of depositing the second protective film, the first dielectric layer (first thin film) and the second dielectric layer (second thin film) of the second protective film are consistent with the first dielectric layer (AlON thin film) and the second dielectric layer (SiON thin film) of the first protective film, respectively.

[0138] The nitride semiconductor laser element prepared in Example 3 was packaged and then subjected to long-term reliability testing. The test results showed that its equivalent long-term aging life exceeded 40,000 hours.

[0139] Example 4

[0140] The difference from Example 1 is that:

[0141] The surface of the gallium nitride substrate facing the epitaxial layer is oriented with a 15° tilt from the C-axis to the M-axis.

[0142] The nitride semiconductor laser element prepared in Example 4 was packaged and then subjected to long-term reliability testing. The test results showed that its equivalent long-term aging life exceeded 40,000 hours.

[0143] Example 5

[0144] The difference from Example 1 is that:

[0145] The orientation of the gallium nitride substrate towards the epitaxial layer side is C-axis oriented.

[0146] The nitride semiconductor laser element prepared in Example 5 was packaged and then subjected to long-term reliability testing. The test results showed that its equivalent long-term aging life exceeded 40,000 hours.

[0147] Example 6

[0148] The difference from Example 1 is that:

[0149] The orientation of the gallium nitride substrate towards the epitaxial layer side is such that the C-axis is tilted towards the M-axis at a 17° angle.

[0150] The nitride semiconductor laser element prepared in Example 6 was packaged and then subjected to long-term reliability testing. The test results showed that its equivalent long-term aging life was 20,000 hours.

[0151] Example 7

[0152] The difference from Example 3 is that:

[0153] In the first protective film deposition step, the oxygen content of the SiON film is reduced to 4 wt%.

[0154] The nitride semiconductor laser element prepared in Comparative Example 1 was packaged in TO (Transistor Outline) and then subjected to long-term reliability testing. The test results showed that its equivalent long-term aging life was 30,000 hours.

[0155] Example 8

[0156] A nitride semiconductor laser element is prepared by the following method:

[0157] A semiconductor substrate is fabricated, comprising a gallium nitride substrate and an epitaxial layer grown on one side surface of the gallium nitride substrate. The orientation of the gallium nitride substrate toward the epitaxial layer side surface is such that the C-axis is tilted toward the M-axis at 3°. The semiconductor substrate has a first cleaving end face (light-emitting end face) and a second cleaving end face (reflecting end face), and a resonant cavity is formed between the first cleaving end face and the second cleaving end face.

[0158] Deposition of the first protective film: First, a 30 nm thick AlN film is deposited on the first cleavage end face of the semiconductor substrate; then, a 50 nm thick SiON film is deposited, with an oxygen content of 5 wt%; finally, a 130 nm thick Al2O3 film and a 100 nm thick Ta2O5 film are deposited on the outside of the SiON film. The reflectivity of the first protective film at a wavelength of 460 nm reaches 20%.

[0159] Deposition of the second protective film: First, a 30 nm thick AlN film is deposited on the second cleavage face of the semiconductor substrate; then, a 50 nm thick SiON film is deposited with an oxygen content of 5 wt%; then, a 130 nm thick Al2O3 film and a 100 nm thick Ta2O5 film are deposited on the outside of the SiON film. Finally, multiple alternating depositions of SiO2 film and Ta2O5 film are performed, and the total thickness of the third dielectric layer reaches 2500 nm, ultimately making the reflectivity of the second protective film ≥98% at a wavelength of 460 nm.

[0160] The nitride semiconductor laser element prepared in Example 6 was packaged in TO (Transistor Outline) and then subjected to long-term reliability testing. The final test results showed that its equivalent long-term aging life exceeded 40,000 hours.

[0161] Example 9

[0162] The difference from Example 8 is that:

[0163] In the first protective film deposition step, the AlN film thickness was 150 nm, the SiON film thickness was 250 nm, and the oxygen content of the SiON film was 30 wt%. Finally, a 150 nm Al2O3 film and an 80 nm Ta2O5 film were deposited successively on the outside of the SiON film. The reflectivity of the first protective film at a wavelength of 460 nm reached 15%.

[0164] In the step of depositing the second protective film, the first dielectric layer (first thin film) and the second dielectric layer (second thin film) of the second protective film are consistent with the first dielectric layer (AlN thin film) and the second dielectric layer (SiON thin film) of the first protective film, respectively.

[0165] The nitride semiconductor laser element prepared in Example 7 was packaged in TO (Transistor Outline) and then subjected to long-term reliability testing. The final test results showed that its equivalent long-term aging life exceeded 40,000 hours.

[0166] Example 10

[0167] The difference from Example 8 is that:

[0168] In the first protective film deposition step, the oxygen content of the SiON film is reduced to 4%.

[0169] The nitride semiconductor laser element prepared in Comparative Example 1 was packaged in TO (Transistor Outline) and then subjected to long-term reliability testing. The test results showed that its equivalent long-term aging life was 30,000 hours.

[0170] Comparative Example 1

[0171] The difference from Example 1 is that:

[0172] In the first protective film deposition step, the oxygen content of the AlON film is increased to 50%.

[0173] The nitride semiconductor laser element prepared in Comparative Example 1 was packaged in TO (Transistor Outline) and then subjected to long-term reliability testing. The test results showed that its equivalent long-term aging life did not exceed 5000 hours.

[0174] Comparative Example 2

[0175] The difference from Example 1 is that:

[0176] In the first protective film deposition step, the oxygen content of the SiON film is increased to 30 wt%.

[0177] The nitride semiconductor laser element prepared in Comparative Example 2 was packaged and then subjected to long-term reliability testing. The test results showed that its equivalent long-term aging life did not exceed 10,000 hours.

[0178] Comparative Example 3

[0179] The difference from Example 6 is that:

[0180] In the first protective film deposition step, the oxygen content of the SiON film is increased to 35 wt%.

[0181] The nitride semiconductor laser element prepared in Comparative Example 3 was packaged and then subjected to long-term reliability testing. The test results showed that its equivalent long-term aging life did not exceed 5000 hours.

[0182] analyze:

[0183] By comparing Examples 1-7 with Comparative Examples 1-2, it can be demonstrated that in a protective film structure in which the material of the first dielectric layer includes aluminum oxynitride and the material of the second dielectric layer includes silicon oxynitride, when the oxygen content of the first dielectric layer is ≤40wt% and the oxygen content of the second dielectric layer is less than that of the first dielectric layer, the chemical stability of the protective film is relatively good, which can effectively improve the long-term reliability life of the semiconductor laser element.

[0184] By comparing Example 6 with Examples 1, 4, and 5, it can be demonstrated that by controlling the angle of the C-axis of the surface of the gallium nitride substrate facing the epitaxial layer towards the M-axis to be within 0° to 15°, it is beneficial to improve the stability of the semiconductor laser device and can effectively improve the long-term reliability life of the semiconductor laser device.

[0185] By comparing Example 7 with Example 3, it can be demonstrated that when the oxygen content of the second dielectric layer is ≥5wt% and <40wt%, the chemical stability of the protective film is better, which is more conducive to improving the long-term reliability life of semiconductor laser devices.

[0186] By comparing Examples 8-10 with Comparative Example 3, it can be demonstrated that in the protective film structure where the first dielectric layer is made of aluminum nitride and the second dielectric layer is made of silicon oxynitride, the chemical stability of the protective film is relatively excellent when the oxygen content of the second dielectric layer is ≤30wt%, which can effectively improve the long-term reliability lifespan of the semiconductor laser device. Specifically, when the oxygen content of the second dielectric layer is between 5wt% and 30wt%, the chemical stability of the protective film is even better, further contributing to improving the long-term reliability lifespan of the semiconductor laser device.

[0187] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A semiconductor laser element, characterized in that, include: A semiconductor substrate having a light-emitting end and a reflective end disposed opposite to each other; A protective film is disposed at the light-emitting end and / or the reflective end. The protective film includes a first dielectric layer and a second dielectric layer stacked sequentially from the inside to the outside. The material of the first dielectric layer includes aluminum oxynitride, and the oxygen content of the first dielectric layer is ≤40wt%. The material of the second dielectric layer includes silicon oxynitride, and the oxygen content of the second dielectric layer is less than that of the first dielectric layer.

2. The semiconductor laser element as described in claim 1, characterized in that, The oxygen content of the second dielectric layer is M, where 5wt% ≤ M < 40wt%.

3. A semiconductor laser element, characterized in that, include: A semiconductor substrate having a light-emitting end and a reflective end disposed opposite to each other; A protective film is disposed at the light-emitting end and / or the reflective end. The protective film includes a first dielectric layer and a second dielectric layer stacked sequentially from the inside to the outside. The material of the first dielectric layer includes aluminum nitride, and the material of the second dielectric layer includes silicon oxynitride. The oxygen content of the second dielectric layer is ≤30wt%.

4. The semiconductor laser element as described in claim 3, characterized in that, The oxygen content of the second dielectric layer is 5 wt% to 30 wt%.

5. The semiconductor laser element according to any one of claims 1-4, characterized in that, The thickness of the first dielectric layer is 10 nm to 300 nm; and / or, The thickness of the second dielectric layer is 3nm to 300nm.

6. The semiconductor laser element according to any one of claims 1-4, characterized in that, The first dielectric layer has a C-axis or M-axis crystal orientation.

7. The semiconductor laser element according to any one of claims 1-4, characterized in that, The silicon oxynitride in the second dielectric layer has a polycrystalline or amorphous crystal structure.

8. The semiconductor laser element according to any one of claims 1-4, characterized in that, The protective film further includes a third dielectric layer disposed on the side of the second dielectric layer facing away from the first dielectric layer, wherein the material of the third dielectric layer includes one or more of oxides, nitrides, and oxynitrides.

9. The semiconductor laser element as described in claim 8, characterized in that, The protective film at the light-emitting end is designated as a first protective film. The first protective film includes n layers of the third dielectric layer, where n is a positive integer, 2≤n≤6. The material of the n layers of the third dielectric layer independently includes one or more of oxides, nitrides, and oxynitrides.

10. The semiconductor laser element as claimed in claim 9, characterized in that, The reflectivity of the first protective film is 10% to 30% in the 400nm to 550nm wavelength range.

11. The semiconductor laser element as claimed in claim 8, characterized in that, The protective film at the reflective end is a second protective film. The second protective film includes m layers of the third dielectric layer, where m is a positive integer and m ≥ 10. The material of the m layers of the third dielectric layer independently includes one or more of oxides, nitrides, and oxynitrides.

12. The semiconductor laser element as claimed in claim 11, characterized in that, The second protective film has a reflectivity of ≥98% in the 400nm to 550nm wavelength range.

13. The semiconductor laser element as described in claim 8, characterized in that, The oxide includes one or more of aluminum oxide, silicon oxide, tantalum oxide, titanium oxide, hafnium oxide, zirconium oxide, niobium oxide, and yttrium oxide; and / or, The nitrogen oxides include one or more of aluminum oxynitride, silicon oxynitride, tantalum oxynitride, and titanium oxynitride; and / or, The nitride film includes one or more of silicon nitride, tantalum nitride, titanium nitride, and aluminum nitride.

14. The semiconductor laser element as claimed in claim 8, characterized in that, The thickness of the third dielectric layer is 150 nm to 400 nm.

15. The semiconductor laser element according to any one of claims 1-4, characterized in that, The semiconductor substrate includes a gallium nitride substrate and an epitaxial layer grown on the surface of the gallium nitride substrate, wherein the orientation of the surface of the gallium nitride substrate facing the epitaxial layer is such that the C-axis is tilted towards the M-axis at a angle of 0° to 15°.

16. A method for fabricating a semiconductor laser element, characterized in that, Includes the following steps: A semiconductor substrate is provided, and a first dielectric layer is disposed at the light-emitting end and / or the reflective end of the semiconductor substrate. The material of the first dielectric layer includes aluminum oxynitride, and the oxygen content of the first dielectric layer is ≤40wt%. A second dielectric layer is disposed on the surface of the first dielectric layer, the material of the second dielectric layer including silicon oxynitride, and the oxygen content of the second dielectric layer is less than the oxygen content of the first dielectric layer.

17. A method for fabricating a semiconductor laser element, characterized in that, Includes the following steps: A semiconductor substrate is provided, and a first dielectric layer is disposed at the light-emitting end and / or the reflective end of the semiconductor substrate, wherein the material of the first dielectric layer includes aluminum nitride; A second dielectric layer is disposed on the surface of the first dielectric layer, the material of the second dielectric layer including silicon oxynitride, and the oxygen content of the second dielectric layer is ≤30wt%.

18. An electronic device, characterized in that, It includes semiconductor laser elements as described in any one of claims 1-15, or semiconductor laser elements prepared by the preparation method described in claim 16 or 17.

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