Resonator cavity surface passivation film of semiconductor laser device, manufacturing method and device

Abstract

The application discloses a resonant cavity surface passivation film of a semiconductor laser device, a manufacturing method and the device, and relates to the technical field of semiconductor laser devices. The resonant cavity surface passivation film comprises a passivation layer and a protective layer. The passivation layer directly covers the resonant cavity surface of the semiconductor laser device; the protective layer covers the passivation layer; the passivation layer and the protective layer are manufactured in the same sulfur-containing compound solution; and the material of the protective layer is a wide-bandgap sulfur oxide material. In the manner, the application can improve the catastrophic optical mirror damage resistance of the semiconductor laser device, increase the maximum output power of the semiconductor laser device, and make the resonant cavity surface passivation film effective for a long time, thereby enhancing the reliability of the semiconductor laser device and prolonging the service life of the semiconductor laser device.

Description

Technical Field

[0001] This application relates to the field of selective passivation technology for semiconductor surfaces, and in particular to the resonant cavity surface passivation film, fabrication method, and device for semiconductor laser devices. Background Technology

[0002] Catastrophic optical mirror damage (COMD) is a significant factor affecting the reliability, lifespan, and maximum output power of high-power semiconductor lasers. During laser output, the powerful radiative flux within the resonant cavity passes through the cavity surface. Electrons and holes recombine nonradiatively at the cavity surface, increasing the temperature. This temperature rise reduces the bandgap width of the material, accelerating laser absorption at the cavity surface and promoting oxidation and defect diffusion. Oxidation increases the surface state density of the cavity surface, further accelerating nonradiative recombination in the cavity surface region. This creates a positive feedback process. When the temperature of the cavity surface exceeds the melting point of the material, the cavity surface melts, causing the semiconductor laser device to fail.

[0003] Resonant cavity surface passivation technology for semiconductor lasers is one of the effective methods to mitigate COMD, improving the resistance to COMD and reliability of semiconductor lasers, and extending their service life. Among existing technologies, the most successful passivation technique for mitigating resonant cavity surface catastrophe involves dissociating the wafer in ultra-high vacuum to generate bar strips and then depositing silicon on the resonant cavity surface. However, this method is difficult to operate, expensive, and has low production efficiency. Therefore, the development of mass production technology that involves dissociating the wafer in an atmospheric environment to generate bar strips and then performing resonant cavity surface passivation has attracted particular attention. Sulfidation is an effective method for removing native oxides and surface defects from the surface of compound semiconductors, effectively increasing the COMD threshold of semiconductor laser devices.

[0004] Wet vulcanization is widely used because it is simple, easy to implement, and inexpensive. However, wet vulcanization has the following problem: the passivation film formed on the resonant cavity surface by wet vulcanization is easily oxidized or volatilized, which leads to the failure of the passivation effect of the passivation film. Therefore, it is necessary to form a protective layer on the passivation film immediately after its formation to maintain its stability. This invention proposes a solution to this problem. Summary of the Invention

[0005] The main technical problem addressed in this application is to provide a method for fabricating a passivation film on the resonant cavity surface of a semiconductor laser device. This method can increase the threshold for COMD (Common Occurrence of Defects) and ensure the passivation film remains effective for a long time, thereby improving the reliability and extending the lifespan of the semiconductor laser device. Furthermore, this method is a novel region-selective passivation technique, where the passivation film is formed almost exclusively on the resonant cavity surface of the semiconductor laser device.

[0006] To solve the above-mentioned technical problems, one technical solution adopted in this application is: to provide a resonant cavity surface passivation film for a semiconductor laser device, the resonant cavity surface passivation film comprising: a passivation layer covering the resonant cavity surface of the semiconductor laser device; and a protective layer covering the passivation layer, wherein the passivation layer and the protective layer are formed in the same sulfur-containing compound solution, and the material of the protective layer is a wide-bandgap sulfur oxide material.

[0007] To solve the above-mentioned technical problems, another technical solution adopted in this application is: to provide a semiconductor laser device, the semiconductor laser device including a resonant cavity surface passivation film, the resonant cavity surface passivation film being the resonant cavity surface passivation film provided by the above technical solution.

[0008] To address the aforementioned technical problems, this application provides a method for fabricating a passivation film on the resonant cavity surface of a semiconductor laser device. This method includes: depositing a thin film of a sulfide passivation layer onto the resonant cavity surface of the semiconductor laser device; and depositing a thin film of a protective layer onto the passivation layer using photochemical deposition. The protective layer is made of a wide-bandgap sulfur oxide material. The passivation layer and the protective layer are formed in the same sulfur-containing compound solution.

[0009] The beneficial effects of this application are as follows: Unlike the prior art, the resonant cavity surface passivation film of this application includes: a passivation layer covering the resonant cavity surface of the semiconductor laser device; and a protective layer covering the passivation layer. The passivation layer and the protective layer are formed in the same sulfur-containing compound solution, and the material of the protective layer is a wide-bandgap sulfur oxide material. The passivation layer process has two functions: (1) removing natural oxides, contaminants, and surface defects on the resonant cavity surface caused by contact with air, and saturating the dangling bonds on the resonant cavity surface with the passivation layer material to reduce the surface state density; (2) forming a dense passivation layer on the resonant cavity surface, effectively isolating the semiconductor from the outside world and preventing re-oxidation. Furthermore, the fact that the passivation layer and the protective layer are formed in the same sulfur-containing compound solution simplifies the fabrication process and improves the fabrication efficiency of the resonant cavity surface passivation film. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Wherein:

[0011] Figure 1 This is a schematic diagram of one embodiment of the resonant cavity surface passivation film of the semiconductor laser device of this application;

[0012] Figure 2 This is a schematic diagram of one embodiment of the semiconductor laser device of this application;

[0013] Figure 3This is a flowchart of one embodiment of the method for fabricating the resonant cavity surface passivation film of the semiconductor laser device of this application;

[0014] Figure 4 This is a schematic diagram of the passivation film completed on the resonant cavity surface of a specific laser diode in the semiconductor laser device of this application;

[0015] Figure 5 This is a schematic diagram of an apparatus for passivating the resonant cavity surface and preparing a wide-bandgap sulfur oxide protective layer by PCD in a specific embodiment of the method for fabricating the resonant cavity surface passivation film of the semiconductor laser device of this application.

[0016] Figure 6 This application combines sulfur passivation and Zn(S) 1-δ O δ The protective layer is applied to the output power-current relationship of a 1064nm semiconductor laser device. The solid line represents the semiconductor laser device with a passivation film, and the dashed line represents the semiconductor laser device with sulfide passivation but without Zn(S) 1-δ O δ The former has a protective layer, and the power of COMD generated by the former is about 50% higher than that of the latter. Detailed Implementation

[0017] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0018] Before describing this application in detail, let me first introduce the prior art related to this application.

[0019] Resonant cavity surface passivation technology for semiconductor lasers is one of the effective methods to increase the threshold for COMD and mitigate it, thereby improving the resistance to COMD and reliability of semiconductor lasers and extending their service life. The most successful passivation technology in the current field for mitigating resonant cavity surface catastrophe involves dissociating the wafer in ultra-high vacuum to generate bar strips and then depositing silicon on the resonant cavity surface. However, this passivation method is difficult to operate, expensive, and has low production efficiency. Therefore, it is necessary to dissociate the bar strips in an atmospheric environment before performing resonant cavity surface passivation. The main principles of resonant cavity surface passivation technology after dissociating the bar strips in an atmospheric environment include two aspects: First, removing natural oxides, contaminants, and surface defects generated on the resonant cavity surface due to contact with air, creating a passivation layer that saturates the dangling bonds on the resonant cavity surface, and isolating the semiconductor from external contact to prevent re-oxidation of the semiconductor; this is usually done using wet or dry methods. Second, forming a dense dielectric thin film on the resonant cavity surface to protect the passivation layer and ensure its long-term effectiveness; this is usually done using physical vapor deposition or chemical vapor deposition.

[0020] Sulfidation is an effective method for removing native oxides, contaminants, and surface defects from the surface of compound semiconductors, thereby increasing the COMD threshold of semiconductor laser devices. Sulfidation methods are divided into wet sulfidation and dry sulfidation, with wet sulfidation being more widely reported. Wet sulfidation mainly utilizes a sulfur-containing solution to react with the semiconductor, while dry sulfidation generally uses sulfur-containing plasma to treat the semiconductor. Wet sulfidation of the resonant cavity surface of a semiconductor laser involves immersing the resonant cavity surface in a sulfur-containing solution, such as aqueous solutions or / and organic solutions of ammonium sulfide ((NH4)2S), sodium sulfide (Na2S), thiourea (CS(NH2)2), or thioacetamide (CH3CSNH2), to remove native oxides, contaminants, and surface defects from the resonant cavity surface. This process then forms a sulfide and a sulfur passivation layer on the resonant cavity surface, i.e., a thin film after the sulfidation reaction. While wet sulfurization is simple and inexpensive, it suffers from several problems: The passivation effect in the sulfurization process relies on several to tens of atomic layers of sulfides and sulfur on the resonant cavity surface. After the sulfurized resonant cavity surface is exposed to air for a period, the sulfur oxidizes or volatilizes, causing the semiconductor material on the resonant cavity surface to be re-oxidized, thus negating the passivation effect. Furthermore, even if the laser chip with the sulfurized resonant cavity surface is removed from the solution, dried, and quickly placed in a coating device for subsequent deposition of the optical thin film on the resonant cavity surface, there is still a high probability of sulfurization failure. This is because optical thin film deposition is typically performed in a vacuum and / or high-temperature environment, which more readily causes sulfur volatilization, leading to the failure of the passivation effect of wet sulfurization.

[0021] This application involves coating a sulfurized passivation layer onto the resonant cavity surface of a semiconductor laser device, followed immediately by a protective layer. The protective layer is made of a wide-bandgap sulfur oxide material, which prevents the sulfur from disappearing from the resonant cavity surface. The passivation film on the resonant cavity surface of the semiconductor laser device in this application serves two main purposes: passivation effect and stability. Choosing a wide-bandgap sulfur oxide material as the protective layer prevents laser absorption by the protective layer material and prevents passivation layer failure. This approach enhances the semiconductor laser device's resistance to COMD, increases its maximum output power, and ensures the long-term effectiveness of the passivation film, thereby improving the reliability and extending the lifespan of the semiconductor laser device.

[0022] The present application will now be described in detail with reference to the accompanying drawings and embodiments.

[0023] See Figure 1 , Figure 1 This is a schematic diagram of one embodiment of the resonant cavity surface passivation film of the semiconductor laser device of this application. The resonant cavity surface passivation film 100 includes: a passivation layer 101 and a protective layer 102.

[0024] In this process, a passivation layer 101 covers the resonant cavity surface of the semiconductor laser device; a protective layer 102 covers the passivation layer 101. The passivation layer 101 and the protective layer 102 are formed in the same sulfur-containing compound solution, and the material of the protective layer 102 is a wide bandgap material.

[0025] In practical applications, the wide bandgap material of the protective layer 102 can be a part or all of the resonant cavity surface optical film of the subsequent semiconductor laser device. After the resonant cavity surface passivation film 100 is completed, other material films can be deposited to adjust the reflectivity and achieve the characteristics of the semiconductor laser device design. For example, Al2O3, SiO2 and TiO2 films are deposited on one end of the resonant cavity surface of the semiconductor laser device so that the overall reflectivity of the passivation film 100 is 5%, while Al2O3, SiO2 and TiO2 multilayer film structure is deposited on the other end so that the overall reflectivity of the passivation film 100 is 99%. Because of the presence of the protective layer 102, the passivation layer 101 is not affected by the subsequent optical film deposition process and will not degrade.

[0026] In this embodiment, after a passivation layer 101 is deposited on the resonant cavity surface of the semiconductor laser device, a protective layer 102 is immediately deposited on the passivation layer 101. The protective layer 102 is made of a wide bandgap material, which can prevent the passivation layer 101 on the resonant cavity surface from failing. The passivation film 100 on the resonant cavity surface of the semiconductor laser device in this application mainly serves two purposes: passivation effect and stability. Choosing to deposit a wide bandgap material immediately as the material of the protective layer 102 can prevent the oxidation or volatilization of the material of the passivation layer 101, prevent the material of the passivation layer 101 from failing, and at the same time prevent the absorption of laser photons by the material of the protective layer 102. In this way, the passivation film 100 on the resonant cavity surface can be effective for a long time, increase the threshold for COMD, and thus ensure the reliability of the semiconductor laser device and extend its service life. Furthermore, since the passivation layer 101 and the protective layer 102 are formed in the same sulfur-containing compound solution, the fabrication process can be simplified and the fabrication efficiency of the passivation film on the resonant cavity surface can be improved.

[0027] In one embodiment, the passivation layer 101 is a sulfur-containing thin film formed by reacting the resonant cavity surface semiconductor epitaxial material of a semiconductor laser device with a sulfur-containing compound solution.

[0028] The sulfide film formed by reacting the resonant cavity surface of a semiconductor laser device with a sulfur-containing compound can be formed by either a dry process or a wet process. Wet sulfidation is more commonly reported, primarily utilizing a sulfur-containing compound solution to react with the semiconductor, while dry sulfidation uses sulfur-containing plasma to treat the semiconductor. Generally, wet sulfidation of the resonant cavity surface of a semiconductor laser device involves immersing the resonant cavity surface in a sulfur-containing compound solution, such as an aqueous solution or / and organic solution of ammonium sulfide, sodium sulfide, thiourea, or thioacetamide, to remove native oxides and contaminants from the resonant cavity surface, thereby forming a sulfide passivation layer, i.e., a sulfur-containing film after the sulfidation reaction. In the examples of this application, thiosulfate can be used instead of the aforementioned sulfides. Specifically, the sulfur-containing compound solution contains at least a thiosulfate sulfide solution, and the solvent is water or an organic solution, or a mixture of water and organic solution. Another advantage of using thiosulfates is that they are odorless and environmentally friendly, unlike the aforementioned ammonium sulfide, sodium sulfide, thiourea, or thioacetamide, which emit an unpleasant odor.

[0029] In one embodiment, the chemical solution in the sulfide passivation method contains thiosulfate ions (S₂O₃). 2- ), thiosulfonate (R-S2O2) - ), thiophosphate (SPO) 3- ) or dithiophosphate (S2PO2) 3- ( ) serves as the source of sulfur for the passivation layer 101.

[0030] The passivation layer 101 has a thickness of several atomic layers to tens of atomic layers.

[0031] In one embodiment, the protective layer 102 is made of a wide-bandgap sulfur oxide material; the thickness of the protective layer 102 is 1-800 nm, for example: 1 nm, 5 nm, 10 nm, 100 nm, 200 nm, 400 nm, 600 nm or 800 nm, etc.

[0032] In this embodiment, the material of the protective layer 102 is a wide-bandgap sulfur oxide material. On the one hand, it can prevent the absorption of laser photons by the material of the protective layer 102 and prevent the oxidation or volatilization of the material of the passivation layer 101. Moreover, both the passivation layer 101 and the protective layer 102 are sulfur-containing compounds, and the materials are compatible with each other. On the other hand, the formation process of the protective layer 102 is compatible with the process of the sulfide passivation layer, that is, both processes are completed in the same sulfur-containing compound solution.

[0033] In one specific embodiment, the wet process for depositing sulfur oxide thin films includes PCD (Photochemical Deposition), Chemical Bath Deposition (CBD), electroplating, etc.

[0034] Compared with other methods, the PCD method has the advantages of deposition area selectivity (i.e., depositing sulfur oxide films only in areas irradiated by ultraviolet light), simple process, low cost, no need for expensive vacuum equipment, easy control of experimental conditions, and easy matching and integration with the wet vulcanization process of passivation layer.

[0035] In the deposition process of the wide-bandgap sulfur oxide thin film (protective layer), ultraviolet light is used to irradiate the resonant cavity surface of the semiconductor laser device. Furthermore, the ultraviolet light irradiation method is either continuous or intermittent. Furthermore, the wavelength of the ultraviolet light is less than 400 nm. The ultraviolet light source includes at least one of the following: Ar2*, Kr2*, Xe2*, F2*, Cl2*, Br2*, I2*, NeF*, ArF*, ArCl*, ArBr*, KrF*, KrCl*, KrBr*, KrI*, XeF*, XeCl*, XeBr*, XeI* excimer lamps, mercury lamps, xenon lamps, mercury-xenon lamps, deuterium arc lamps, hydrogen arc lamps, xenon-antimony arc lamps, carbon arc lamps, metal halide lamps, UV-B ultraviolet lamps, ultraviolet light-emitting diodes, and ultraviolet lasers.

[0036] In one embodiment, the chemical solution in the PCD process contains thiosulfate ions (S₂O₃). 2- ), thiosulfonate (R-S2O2) - ), thiophosphate (SPO) 3- ) or dithiophosphate (S2PO2) 3- It serves as a source of sulfur for wide-bandgap sulfur oxides.

[0037] In one embodiment, the PCD method uses a chemical solution containing at least one of the following ions or complexes: zinc, cadmium, magnesium, calcium, strontium, barium, aluminum, gallium, indium, tin, antimony, bismuth, or manganese, as a source of cations for the wide-bandgap sulfur oxides.

[0038] Taking zinc oxysulfide as an example, the pH of the solution, deposition temperature, UV irradiation method and time, Zn to S equivalent ratio, metal ion complexing agent, and distance of UV light penetration from the solution to the resonant cavity surface in the PCD system all affect the deposition rate, oxygen content, stress state, transmittance, density, and surface morphology of wide-bandgap oxysulfide films. With appropriate solution formulations and parameters, PCD wide-bandgap oxysulfide films can achieve characteristics such as high deposition rate, low oxygen content, low stress, high transmittance, high density, and uniform film coverage. Specifically, PCD can accurately control the deposition location of wide-bandgap oxysulfide films through selective UV irradiation. By selectively irradiating the resonant cavity surface of semiconductor laser devices with UV light, the oxysulfide film is deposited only on the resonant cavity surface, which perfectly meets the requirements of the resonant cavity surface passivation film and avoids deposition in non-resonant cavity areas, making this technology easier to integrate into the fabrication process of semiconductor laser devices.

[0039] The chemical reactions of PCD zinc sulfide (ZnS) thin films illustrate the regional selective deposition process. The chemical reaction formula for the formation of zinc sulfide is as follows:

[0040] Zn 2+ +S+2e - →ZnS[1]

[0041] This requires zinc ions, sulfur atoms, and electrons;

[0042] The photochemical reaction of thiosulfate ions can provide sulfur atoms and electrons; the reaction is as follows:

[0043] S2O3 2- +hν→S+SO3 2- [2]

[0044] 2S2O3 2- +hν→S4O6 2- +2e - [3]

[0045] S2O3 2- +SO3 2- +hν→S3O6 2- +2e - [4]

[0046] Where hν represents ultraviolet photons.

[0047] Zinc ions can be provided by adding zinc-containing salts, thus the solution contains the necessary components for the reaction to produce zinc sulfide. When irradiated with ultraviolet light, a zinc sulfide film can be produced.

[0048] In addition, thiosulfate is a diprotic acid, which will dissociate in aqueous solution to produce HS₂O₃. - and S2O3 2- :

[0049]

[0050]

[0051] H2S2O3 and HS2O3 at constant temperature - and S2O3 2- The concentrations will reach equilibrium, with H2S2O3 and HS2O3 in the solution. - and S2O3 2- coexist.

[0052] In acidic solution, thiosulfate ions react with hydrogen ions to produce sulfur atoms, as shown in the following reaction:

[0053]

[0054] Although this reaction provides sulfur atoms, it does not produce electrons in the absence of ultraviolet light irradiation, so ZnS films cannot be formed. ZnS films can only be deposited in areas irradiated by ultraviolet light. This is the manifestation of the regional selectivity of PCD and at the same time provides an opportunity for sulfur passivation.

[0055] In PCD solutions, zinc ions originate from zinc-containing salts, such as zinc sulfate (ZnSO4), while sulfur atoms mainly originate from thiosulfate ions (S2O3). 2- In photochemical reactions under ultraviolet light irradiation, the pH adjuster of the solution is usually sulfuric acid (H2SO4) or ammonia, and the complexing agent is usually ethylenediaminetetraacetic acid (EDTA, C). 10 H 16 Complexing agents, such as N2O8, tartaric acid (C4H6O6), and citric acid (CHO), reduce the concentration of Zn in the solution. 2+ Ion concentration is used to prevent excess Zn or the formation of Zn(OH)2 precipitate during ZnS formation.

[0056] During the PCD reaction, other parallel chemical reactions also occur simultaneously, including the reaction of metal ions with OH- in the solution. - Ionic reactions form hydroxides, taking zinc as an example:

[0057]

[0058]

[0059]

[0060]

[0061]

[0062] Therefore, oxygen is unavoidably present in the coating, mainly because water molecules and the aforementioned metal ions combined with hydrogen and oxygen are trapped in the coating along with the sulfide deposition. This is generally expressed as Zn(S,O,OH) or Zn(S,OH). The hydrogen content is difficult to measure, and since hydrogen generally has no significant impact on applications, it is often ignored. Therefore, for this type of sulfide coating, this application uses M... m (S 1-δ O δ ) n The form is represented as follows: M represents metal atoms, m and n represent the stoichiometric ratio of the compound, and δ is the oxygen content; other impurity elements such as carbon and nitrogen are also present, but their content is very low and has almost no effect on the coating properties, so they are ignored.

[0063] Before the PCD reaction to form the protective layer, a passivation layer is formed. The solution used in this stage is the same as the solution used in the aforementioned PCD method for forming the protective layer, but without ultraviolet light irradiation. Therefore, the PCD reaction does not occur, and sulfur oxides are not generated, such as Zn(S). 1-δ O δ At this time, the thiosulfate ions in the solution react with hydrogen ions to produce sulfur atoms, as shown in the above chemical reaction formula [7]. These sulfur atoms and / or hydrogen ions react with the semiconductor material of the resonant cavity surface of the laser, first dissolving the natural oxides on the surface, and then reacting to form a sulfide and sulfur passivation layer. It may also include the chemical reaction of sulfur and oxygen substitution. This sulfur and sulfide film is the Figure 1 Passivation layer 101. This passivation layer 101, together with the subsequently plated protective layer 102, forms... Figure 1 The passivation film is 100.

[0064] The sulfidation reaction corresponding to the formation of the passivation layer 101 requires careful selection of sulfur-containing reactants, as some sulfides will produce sulfur dioxide when dissolved in water. 2- or / and HS - Ions, such as ammonium sulfide, sodium sulfide, thiourea, and thioacetamide, react immediately with metal ions in the solution to form sulfides that deposit on the resonant cavity surface, thus causing CBD (Continuous Passivation). While these sulfides do have a passivation effect, it is relatively poor, likely because the natural oxides on the resonant cavity surface have not been sufficiently removed before the sulfide deposits. This application primarily uses thiosulfate as an example, but substances with the same effect are not limited to thiosulfate; others include thiophosphate (PSO3). 3- ), dithiophosphate (PS2O2) 3- ), thiosulfonate (S2O4 3- Others also have similar passivation effects and are suitable for subsequent PCD reactions.

[0065] The above description of the sulfidation reaction forming the passivation layer only describes the sulfidation reaction between sulfur-containing anions and the resonant cavity surface. However, metal cations also exist in the solution, and the chemical reaction between metal ions and the resonant cavity surface must also be considered. Other chemical reactions competing with sulfidation may also occur. When the electrochemical potential energy of metal ions in the solution is higher than that of the epitaxial or substrate material, the epitaxial or substrate material will oxidize, transforming into ions that dissolve in the solution. Simultaneously, the metal ions present in the solution will be reduced to metal atoms and attach to the resonant cavity surface. This can be illustrated by the following simplified chemical reaction equation:

[0066] M + +GaAs→M (GaAs) +Ga 3+

[13]

[0067] M + +GaAs + H₂O → M (GaAs) +H2AsO4 -

[14]

[0068] M + M represents the metal ions in the solution. (GaAs) This indicates that the metal is attached to the GaAs surface.

[0069] Taking copper as an example, if the solution contains copper ions, their electrochemical potential is higher than that of the epitaxial material (e.g., InGaAs or InGaP) or the substrate material (e.g., GaAs or InP). Therefore, copper ions will be reduced to copper atoms, which will adhere to the surface of the epitaxial material or substrate material, forming a copper coating and damaging the passivation film structure. Thus, when designing the passivation film structure, the material of the protective layer must be carefully selected based on the epitaxial and substrate materials to avoid the formation of a metal coating between the passivation film and the epitaxial semiconductor material during the passivation process. Based on these considerations, zinc sulfide is a good choice. Zinc ions have a low electrochemical potential and will not be reduced to metallic zinc during the passivation process. Furthermore, its band gap (3.54 eV) is relatively large, exceeding the photon energy of most semiconductor laser devices, resulting in very low laser absorption. Therefore, this application mainly uses zinc sulfide as an example. When selecting other sulfides with smaller band gaps, the principle that the band gap of the protective layer material must be greater than the photon energy of the laser must be met to avoid excessive laser absorption, which would reduce the resistance and reliability of COMD.

[0070] In one embodiment, the wide-bandgap sulfur oxide material specifically includes: Zn(S) 1-δ O δ ), Cd(S 1-δ O δ ), Mg(S) 1-δ O δ ), Ca(S) 1-δ O δ ), Sr(S1-δ O δ ), Ba(S) 1-δ O δ Al2(S) 1-δ O δ 3. Ga2(S) 1-δ O δ 3. In2(S) 1-δ O δ 3. Sn(S) 1-δ O δ 2. Sn(S) 1-δ O δ ), Sb2(S 1-δ O δ 3. Bi2(S) 1-δ O δ 3. Mn(S) 1-δ O δ At least one of the above-mentioned materials, that is, the wide-bandgap sulfur oxide material can be a single material or a mixture of two or more materials, wherein δ represents the oxygen atom content in the sulfur oxide material, and the range of δ is: 0.2 ≥ δ > 0.

[0071] Furthermore, the material of the protective layer 102 is a mixture containing wide-bandgap sulfur oxide materials; for example, the mixture containing wide-bandgap sulfur oxide materials includes: Zn(S) 1-δ O δ ) and Cd(S 1-ξ O ξ A mixture of Mg(S) 1-δ O δ ) and Ca(S 1-ξ O ξ A mixture of Sr(S) 1-δ O δ ) and Ba(S 1-ξ O ξ A mixture of Al2(S) 1-δ O δ )3 and Ga2(S 1-ξ O ξ A mixture of Al2(S)3 and Al2(S)3 1-δ O δ )3 and Mg(S) 1-ξ O ξ A mixture of Ca(S) 1-δ O δ ) and Sn(S 1-ξ O ξAt least one of the following mixtures: Zn(S)2, meaning the mixture containing wide-bandgap sulfur oxide materials can be one of the above-mentioned mixtures, or a mixture of two or more of the above-mentioned materials. Wherein, δ represents the oxygen atom content in one sulfur oxide material of the mixture, and ξ represents the oxygen atom content in another sulfur oxide material of the mixture. The ranges of δ and ξ are: 0.2 ≥ δ > 0 and 0.2 ≥ ξ > 0; for example, a mixture containing wide-bandgap sulfur oxide materials is Zn(S)2. 1-δ O δ ) and Cd(S 1-ξ O ξ A mixture of Zn(S); or it can be Zn(S) 1-δ O δ Al2(S) 1-δ O δ )3 and Mg(S) 1-δ O δ ) mixtures, combinations of mixtures, etc.

[0072] Furthermore, the protective layer 102 is made of a wide-bandgap sulfur oxide alloy; for example, wide-bandgap sulfur oxide alloys include (Zn... 1-x Cd x (S) 1-δ O δ ), (Mg 1-x Ca x (S) 1-δ O δ (Zn) 1-x Ca x (S) 1-δ O δ ), (Ca 1-x Sr x (S) 1-δ O δ ), (Mg 1-x-y Ca x Ba y (S) 1-δ O δ ), (Al 1-x Ga x )2(S 1-δ O δ 3. (Zn) 1-x Al x (S) 1-δ O δ (Zn) 1-x Ga x (S) 1-δ O δ (Zn) 1-x Mn x (S) 1-δ O δ(Zn) 1-x-y Cd x Mn y (S) 1-δ O δ At least one of the above-mentioned alloy materials, that is, the wide-bandgap sulfur oxide alloy material can be one of the above-mentioned alloy materials, or a mixture of two or more of the above-mentioned alloy materials. Wherein, x represents the content of one metal in a wide-bandgap sulfur oxide alloy material (an alloy compound of two metals), y represents the content of another metal in a wide-bandgap sulfur oxide alloy material (an alloy compound of three metals), δ represents the oxygen atom content in the sulfur oxide material, the ranges of x and y are: 1 > x, y > 0, and the range of δ is: 0.2 ≥ δ > 0.

[0073] These single, mixed, or alloyed sulfur oxides can be crystalline, amorphous, or a mixture of both.

[0074] With Zn(S) 1-δ O δ As examples of wide-bandgap sulfur oxides, ZnS has a bandgap of 3.54 eV, and ZnO has a bandgap of 3.37 eV. In ZnS, the bandgap decreases when some sulfur is replaced by oxygen. Depending on the preparation conditions, the bandgap of Zn(S) in PCD... 1-δ O δ The optical bandgap width of the PCD thin film ranges from 3.6 to 3.7 eV. The wider optical bandgap compared to ZnS is mainly due to the small size of the crystalline particles in the PCD thin film, resulting in a larger optical bandgap than bulk materials based on the quantum confinement principle or quantum size effect. When a sulfur oxide (e.g., Zn(S)) is selected... 1-δ O δ The bandgap width of the laser is greater than the photon energy of the laser (e.g., wavelength greater than 600 nm). This wide bandgap characteristic does not cause intrinsic absorption of the laser emitted by the semiconductor laser, and the absorption rate is very low. At the same time, the ZnS thin film of the PCD contains a small amount of oxygen, which does not affect the passivation effect of the laser chip resonant cavity surface.

[0075] See Figure 2 , Figure 2 This is a schematic diagram of one embodiment of the semiconductor laser device of this application. The semiconductor laser device 200 includes a resonant cavity surface passivation film 100, which can be any of the resonant cavity surface passivation films mentioned above. For detailed descriptions of related content, please refer to the detailed description of the resonant cavity surface passivation film 100 above, which will not be repeated here.

[0076] See Figure 3 , Figure 3 This is a flowchart of one embodiment of the method for fabricating the resonant cavity surface passivation film of the semiconductor laser device of this application. This method can fabricate the resonant cavity surface passivation film of the semiconductor laser device. For detailed description of the relevant content, please refer to the above-mentioned resonant cavity surface passivation film of the semiconductor laser device, which will not be repeated here.

[0077] The method includes steps S101 and S102.

[0078] Step S101: A thin film of sulfide passivation layer is coated on the resonant cavity surface of the semiconductor laser device.

[0079] Step S102: Cover the passivation layer with a thin film of protective layer, the material of which is wide bandgap sulfur oxide material.

[0080] The passivation layer and the protective layer are formed in the same sulfur-containing compound solution.

[0081] In this embodiment, after covering the resonant cavity surface of the semiconductor laser device with a passivation layer, a protective layer is immediately applied over the passivation layer. The protective layer is made of a wide-bandgap sulfur oxide material, which prevents the passivation effect from failing due to oxidation or volatilization of the passivation layer on the resonant cavity surface. The passivation film on the resonant cavity surface of the semiconductor laser device in this application mainly serves two purposes: passivation effect and stability. Choosing a wide-bandgap sulfur oxide material as the protective layer material reduces the absorption of laser photons by the protective layer material, prevents oxidation or volatilization of the passivation layer material, and prevents passivation layer material failure. In this way, the passivation film on the resonant cavity surface can remain effective for a long time, increasing the threshold for COMD, thereby ensuring the reliability of the semiconductor laser device and extending its service life.

[0082] Specifically, step S101 may include: reacting the resonant cavity surface of the semiconductor laser device with a sulfur-containing compound solution to form a thin film containing sulfur and sulfides covering the resonant cavity surface, the passivation layer having a thickness of several atomic layers to tens of atomic layers. Specifically, a wet sulfidation method is used to form the passivation layer on the resonant cavity surface of the semiconductor laser device; the wet sulfidation method uses a sulfur-containing compound solution containing thiosulfate; the solvent of the sulfur-containing compound solution is water or an organic solvent, or a mixture of water and an organic solvent.

[0083] Specifically, step S102 may include: coating a protective film onto the passivation layer using a PCD method. The sulfur-containing compound solution used contains thiosulfate ions as a source of sulfur for the wide-bandgap sulfur oxide; the sulfur-containing compound solution also contains at least one of the following ions or complex ions: zinc, cadmium, magnesium, calcium, strontium, barium, aluminum, gallium, indium, tin, antimony, bismuth, or manganese, as a source of cations.

[0084] The wavelength of ultraviolet light is less than 400 nm; the light source of ultraviolet light includes at least one of the following: Ar2*, Kr2*, Xe2*, F2*, Cl2*, Br2*, I2*, NeF*, ArF*, ArCl*, ArBr*, KrF*, KrCl*, KrBr*, KrI*, XeF*, XeCl*, XeBr*, XeI* excimer lamps, mercury lamps, xenon lamps, mercury-xenon lamps, deuterium arc lamps, hydrogen arc lamps, xenon-antimony arc lamps, carbon arc lamps, metal halide lamps, UV-B ultraviolet lamps, ultraviolet light-emitting diodes, and ultraviolet lasers.

[0085] The protective layer is made of wide-bandgap sulfur oxide material; the thickness of the protective layer is 1-800 nm.

[0086] See Figure 4 , Figure 4 The diagram shows a laser diode fabricated by wet sulfidation passivation of the resonant cavity surface of a laser chip, followed immediately by PCD to form a wide-bandgap sulfide oxide film. The resonant cavity surface is sequentially covered with a sulfide-containing film 1 and a wide-bandgap sulfide oxide film 2 after the sulfidation reaction. The epitaxial structure includes: an active layer 3, a waveguide layer 4, an n-type cladding layer 5, a p-type cladding layer 6, an n-type semiconductor substrate 7, an n-plane metal electrode 8, a p-plane metal electrode 9, and a p-type heavily doped semiconductor layer 10. The active layer 3, waveguide layer 4, cladding layers 5 and 6, and semiconductor substrate 7 correspond to different materials, such as InGaP / [(Al2O3)2] with a wavelength of 630-680 nm. x Ga 1-x ) 1-y In y ]P / [(Al u Ga 1-u ) 1-v In v In the P / GaAs epitaxial system, the active layer 3 is made of InGaP quantum well, and the waveguide layer 4 is made of [(Al x Ga 1-x ) 1-y In y ]P, the material of cladding layers 5 and 6 is [(Al u Ga 1-u ) 1-v In v [P or AlInP, the waveguide layer 4 and cladding layers 5 and 6 have different material compositions, the former has a smaller band gap and a larger refractive index, and the semiconductor substrate 7 is made of n-GaAs; for example, [(Al x Ga 1-x ) 1- y In y ]As / [(Alx Ga 1-x ) 1-y In y In the As / InP system, the material of active layer 3 is [(Al x Ga 1-x ) 1-y In y As a quantum well, the waveguide layer 4 is made of [(Al u Ga 1-u ) 1-v In v As, the cladding layers 5 and 6 are made of InP, and the semiconductor substrate 7 is made of n-InP; other materials include GaAsP / [(Al) with wavelengths of 750-900nm. x Ga 1-x ) 1-y In y ]P / [(Al u Ga 1-u ) 1-v In v P / GaAs epitaxial systems, In(Al)GaAs / (Al) with wavelengths of 800-1100 nm x Ga 1-x )As / (Al y Ga 1-y As / GaAs epitaxial systems and GaAs / (Al) epitaxial systems with wavelengths of 800-870 nm x Ga 1-x )As / (Al y Ga 1-y As / GaAs epitaxial systems. Wet sulfidation can be used to effectively passivate the surface epitaxial materials of semiconductor laser resonators in various wavelength bands. PCD can also deposit wide-bandgap sulfide films on the sulfidated surface epitaxial materials of semiconductor laser resonators.

[0087] The following is a specific embodiment to illustrate the fabrication method of this application, as well as the passivation film and laser diode device prepared by this method. The details are as follows:

[0088] Passivation was achieved using a wet sulfidation reaction, forming a sulfide film on the resonant cavity surface as a passivation layer. Subsequently, a sulfur oxide film was prepared using the PCD method, initially with Zn(S) 1-δ O δ Taking 0.2≥δ>0 as an example, and using it as a protective layer for passivation, the solutions for wet sulfidation and PCD are sulfur-containing compound solutions. The sulfur source thiosulfate ions in the solution can provide the sulfur required for the sulfidation reaction to form the passivation layer. These thiosulfate ions also provide the sulfur for subsequent PCD preparation of Zn(S) 1-δ Oδ The source of sulfur in the protective layer.

[0089] First, let's explain the process of wet vulcanization and Zn(S) 1-δ O δ The preparation of the protective layer solution is explained, followed by the apparatus for fabricating the passivation film, and then the passivation and Zn(S) plating process for fabricating the passivation layer on the surface of the resonant cavity of the bar. 1-δ O δ The protective layer step is followed by fabricating a laser diode device and testing its COMD resistance.

[0090] 1) Preparation of the solution for making the passivation film:

[0091] Using pure water as a solvent, the components are:

[0092] The zinc sulfate (ZnSO4) concentration is 0.004M; the source of zinc in the coating;

[0093] The sodium thiosulfate (Na2S2O3) concentration is 0.1M; the source of sulfur in the coating.

[0094] Sodium citrate (Na3C6H5O7) at a concentration of 0.01M dissolves in water to form citric acid and citrate ions, which act as complexing agents for zinc ions.

[0095] All solutions were prepared at room temperature using deionized water as the solvent, with an impedance greater than 18 MΩ·cm. Before preparing the solutions, 99.9999% pure nitrogen gas was passed through the deionized water for 30 minutes. The nitrogen bubbles carried away dissolved gases, including oxygen and carbon dioxide, which slowed down the oxidation of thiosulfate, making the solution more stable and extending its service life. Then, specific weights of zinc sulfate, sodium citrate, and sodium thiosulfate were dissolved in a small amount of deionized water. Next, the zinc sulfate solution and sodium citrate solution were mixed and stirred using a ceramic magnetic stirrer. Then, the sodium thiosulfate solution was added to the aforementioned zinc sulfate and sodium citrate mixture and stirred for 2 minutes. This solution was then poured into a volumetric flask, and a small amount of water was added to the volumetric flask to reach the specified volume and mixed thoroughly to achieve the aforementioned solution composition. Finally, the pH of the process solution was adjusted to 5.7 using an aqueous solution of concentrated sulfuric acid and sodium hydroxide, and the solution was prepared for use.

[0096] 2) Apparatus for fabricating passivation films:

[0097] Process equipment such as Figure 5 As shown, the solution is placed in Figure 5 In the quartz vessel, the solution temperature can be raised by a magnetic stirrer, the solution temperature is controlled at 30°C, and nitrogen gas is continuously introduced.

[0098] The ultraviolet light source is a 20W XeI* excimer lamp with a main peak wavelength of 253nm. A converging lens is used to focus the ultraviolet light onto the resonant cavity surfaces of the semiconductor laser device (the front and rear resonant cavity surfaces, respectively). The power density of the ultraviolet light at the resonant cavity surfaces is approximately 100–300 mW / cm². 2 A baffle is placed between the light source and the converging lens to control whether ultraviolet light passes through. The baffle's movement and intervals are controlled by a computer. The design of the quartz vessel ensures that the front and rear cavity surfaces of the resonant cavity are approximately 3 mm away from the inner surface of the quartz vessel's sidewall. Figure 5 The entire apparatus is placed in a dark box, which can prevent ultraviolet light from scattering and causing damage to the human eye. At the same time, it can also prevent the solution from being exposed to ultraviolet light from the environment, thus preventing the decomposition of thiosulfate ions, maintaining the stability of the solution and extending its lifespan.

[0099] 3) Steps for fabricating a passivation film on the surface of the bar resonator:

[0100] First, the wafer from which the laser device has been fabricated is cleaved into bars in an atmospheric environment. Second, PTFE clamps are used to hold the bars, allowing multiple bars to be stacked in parallel at the same time. Then, the bars are immersed in... Figure 5 The solution is subjected to sulfidation passivation (without the UV lamp on) for 5-30 minutes. After sulfidation passivation, a passivation layer is formed on the resonant cavity surface. Then, the UV light source is turned on to form a protective Zn(S) layer. 1-δ O δ The coating process involves the switching of the baffle as a cyclic process. Within one cycle, the ultraviolet light passes through for 10-60 seconds and is blocked for 10-600 seconds. This process is repeated multiple times, meaning the total time the ultraviolet light irradiates the resonant cavity surface of the semiconductor laser device is 30 to 120 minutes. The thickness of the zinc sulfide film can reach approximately 1 to 300 nm.

[0101] After the above-mentioned sulfidation passivation and Zn(S) 1-δ O δ After the plating and passivation film is completed, the bar strip is taken out, rinsed with deionized water to remove the solution, and then dried with nitrogen gas.

[0102] Alternatively, the passivation film can be heat-treated to improve the light transmittance of the passivation layer. However, the heat treatment temperature should not exceed the lowest temperature in the previous wafer fabrication process to avoid damaging the laser.

[0103] Subsequently, depending on the characteristics and requirements of the semiconductor laser device, optical films with the required reflectivity can be deposited on the front and rear resonant cavity surfaces, or the bars can be further cut into single chips or arrays.

[0104] To know Zn(S)1-δ O δ The light transmittance of Zn(S) is determined by the method described above. 1-δ O δ The coating, deposited on a BK7 glass substrate, exhibits high light transmittance. Transmission spectroscopy measurements and Tauc plot calculations revealed a band gap of approximately 3.6 eV, higher than the laser photon energy excited by the aforementioned epitaxial systems, thus meeting the design requirements for laser devices. Furthermore, scanning electron microscopy-energy dispersive spectroscopy analysis of the coating composition showed an oxygen content of δ≈0.04, indicating that the protective layer coating is composed of Zn(S) 0.96 O 0.04 ).

[0105] Based on the above, the resonant cavity surface of a high-power laser bar with a wavelength of 1064nm is subjected to sulfidation passivation and Zn(Si) plating as described above. 0.96 O 0.04 ) protective layer, Zn(S) 0.96 O 0.04 The protective layer is approximately 30 nm thick. Then, optical films are deposited on the front and rear resonant cavity surfaces using electron beam evaporation. The reflectivities of the optical films on the front and rear resonant cavity surfaces are 5% and 99%, respectively. The laser output is mainly emitted from the front resonant cavity surface with a reflectivity of 5%, while the laser emission power from the rear resonant cavity surface is very weak. The laser bar is split into a single laser chip, each containing only one laser diode. This laser chip is then soldered onto a copper-clad aluminum nitride heat sink. Finally, gold wire bonding is applied to complete a simple package, followed by laser device characteristic testing. To verify the effectiveness of the passivation film in this application, a similar laser device was fabricated simultaneously as a reference comparison standard. The only difference is that the latter does not contain Zn(S) 0.96 O 0.04 ) Protective layer. Figure 6 These are the laser output power-current test results for two laser devices. The results show no Zn(S) 0.96 O 0.04 When the current increased to 19A, a COMD occurred at the front resonant cavity surface of the laser device with a protective layer, causing instantaneous failure of the laser device and a drop in laser output power to almost zero. On the other hand, the laser device with Zn(S) protective layer... 0.96 O 0.04 The laser device with the protective layer only experienced COMD when the current rose to 29A, which improved the COMD resistance of the laser device by about 50% compared with the reference comparison laser device. In addition, reliability tests were conducted on 20 of the above-mentioned simple packaged laser devices. After 3000 hours of aging and burning tests at 70°C and operating current, none of them failed.

[0106] Another embodiment uses Mn(S) 1-δ O δ ) replace Zn(S 1-δ O δFor the protective layer material, bulk MnS has a band gap of 3.1 eV, which is greater than the photon energy of most lasers, making it a good candidate. Similarly, Zn(S) can be fabricated using the above method. 1-δ O δ The protective layer material is prepared using the same method as Mn(S) 1-δ O δ In a coating process where MnSO4 was used instead of ZnSO4 as the solution raw material, and other process parameters were slightly modified, the results were similar to those of Zn(S) coating. 1-δ O δ The coating is similar, but Mn(S) 1-δ O δ The light transmittance of the Mn(S) coating is low. Heat treatment (nitrogen atmosphere, 10 minutes) can improve the light transmittance, resulting in a band gap of approximately 3.4 eV and δ ≈ 0.07, indicating that the PCD coating is Mn(S) 0.93 O 0.07 This process and coating method, following the procedure for fabricating a 1064nm laser, are applied to the fabrication of a 980nm laser. Mn(S) 0.93 O 0.07 The protective layer is 15 nm thick, and the reflectivity of the optical film layers on the front and rear resonant cavity surfaces is 3% and 99%, respectively. Heat treatment is performed after the optical film layer is deposited in a vacuum electron beam evaporation apparatus. The result is that the COMD resistance is relatively high compared to Mn(S) 0.93 O 0.07 The protective layer is about 28% higher, which again demonstrates the superiority of the technology in this application. At the same time, this example also illustrates that sulfur oxide films with various band gap widths can be formed through the selection and substitution of metal ions. As long as the principle that the band gap width of sulfur oxide is greater than the photon energy of the laser is met, it can be applied to the fabrication of semiconductor lasers. Such sulfur oxides with a band gap width greater than the photon energy of the laser are called "wide band gap" sulfur oxides.

[0107] Another embodiment is that the protective layer is made of a wide-bandgap sulfur oxide alloy: Al-doped Zn(S) 1-δ O δ ), with (Zn 1-x Al x (S) 1-δ O δ The method of production follows the aforementioned Zn(S) method. 1-δ O δ The solution composition for sulfidation passivation and protective layer plating is as follows:

[0108] The zinc sulfate (ZnSO4) concentration is 0.002M; the source of zinc in the coating;

[0109] The aluminum sulfate (Al2(SO4)3) concentration is 0.002M; the source of aluminum in the coating;

[0110] hydrazine hydrate ， (NH2)2·H2O) concentration is 0.04M, a strong reducing agent, used to reduce the oxygen content in the coating;

[0111] Ammonia solution with a concentration of 0.012M is used as a complexing agent for zinc and aluminum ions.

[0112] The sodium thiosulfate (Na2S2O3) concentration is 0.1M, and the source of sulfur in the PCD coating and sulfidation passivation;

[0113] The band gap of the coating obtained using this solution is approximately 3.7 eV, with x ≈ 0.07 and δ ≈ 0.02, meaning the coating is (Zn... 0.93 Al 0.07 (S) 0.98 O 0.02 X-ray diffraction revealed that this coating has a wurtzite structure with nanoscale crystalline grains. Applying this process and coating to the fabrication of a 640nm laser, following the same procedure used for a 1064nm laser, yielded a Zn... 0.93 Al 0.07 (S) 0.98 O 0.02 The protective layer is 25 nm thick, and the reflectivity of the optical films on the front and rear resonant cavity surfaces is 5% and 99%, respectively. The result is that the COMD resistance is relatively low (Zn). 0.93 Al 0.07 (S) 0.98 O 0.02 The protective layer is about 33% higher. In addition, reliability tests were conducted on 10 of the above-mentioned simple packaged laser devices. After burning at 70°C and operating current for 2600 hours, none of them failed. This result once again demonstrates the superiority and wide applicability of the technology of this application. This example also illustrates that by selecting and adding metal ions and using appropriate metal ion complexing agents, alloy material thin films of sulfur oxides with various band gap widths can be formed. As long as the band gap width of the sulfur oxide is greater than the photon energy of the laser, it can be applied to the fabrication of semiconductor lasers.

[0114] All three embodiments described above use thiosulfate ions as the sulfur source for sulfidation passivation and the deposition of sulfur oxide protective layers. However, in reality, other substances besides thiosulfate ions also exhibit the same effect. These other substances include the following three categories: thiosulfonate ions (R-S2O2). - R is a hydrocarbon group), thiophosphate (SPO) 3- ) or dithiophosphate (S2PO2) 3- This can be substances (salts, acids, esters, etc.) whose chemical structural formulas contain these three types of acid radicals:

[0115] 1) Thiosulfonate (R-S2O2) - Class 1: Ethyl thiosulfonate, Methyl thiosulfonate, Thiobenzene sulfonate, 4-Toluene thiosulfonate, p-Toluene thiosulfonic acid, S-Benzylmethane thiosulfonate, 2-Aminoethyl thiosulfonic acid, Propylmethane thiosulfonate, Amylmethane thiosulfonate, (3-Sulfopropyl)methane thiosulfonate, 1,2-Ethyldimethylmethane thiosulfonate, 2-Aminoethylmethane thiosulfonate, 5-Aminopentylmethane thiosulfonate, S,S'-[1,2-Ethyldimethyldi(oxy-2,1-ethylenediyl)]dimethylmethane thiosulfonate.

[0116] 2) Thiophosphate (SPO) 3- Class 1: Thiophosphates, dimethyl thiophosphate salts, n-butyl thiophosphate triamine, O,O-dimethyl thiophosphate or salts, O,o-diethyl-o-hydrothiophosphate, O,O-dimethyl thiophosphate, potassium diethyl thiophosphate, O,O-diisopropyl thiophosphate, trimethyl thiophosphate, O,O,O-triethyl thiophosphate, O,O,O-triphenyl thiophosphate, 4-aminophenol thiophosphate, O,O-dimethyl thiophosphate, O,O-diethyl thiophosphate, N,N',N”-trimethyl thiophosphate triamide, dimethyl monothiophosphate, O,O-dimethyl-O-(2-ethylthioethyl) thiophosphate, O-2,4-dichlorophenyl-O,O-diethyl thiophosphate, 2-isopropyl-4-methyl-6-pyrimidinyl thiophosphate diethyl ester;

[0117] 3) Dithiophosphate (S2PO2) 3-Class: Dithiophosphate, diisobutyl dithiophosphate, O-m-tolyl-O-p-tolyl dithiophosphate, xylenol dithiophosphate, dimethyl dithiophosphate, O,O-dimethyl dithiophosphate, dithiophosphate-O,O-di(1-methylpropyl) ester, dialkyl dithiophosphate, O,O-dibutyl dithiophosphate, O,O-bis(1,3-dimethylbutyl) dithiophosphate, toluene dithiophosphate, diethyl dithiophosphate, diethyl dithiophosphate, diisopropyl dithiophosphate, dithiophosphate-O,O -Di(1-methylethyl) ester, O-ethyl-S-propyl dithiophosphate, O,O-dimethyl dithiophosphate, O,O'-diethyl dithiophosphate, O,O-diethyl dithiophosphate salt, O,O-diethyl-S-propyl dithiophosphate, dimethoxydithiophosphate methyl acetate, O,O-phenyl dithiophosphate, dimethylphenol dithiophosphate, di(O,O-diisodecyl dithiophosphate-S,S')- salt, di(tetrapropylenephenol) dithiophosphate salt, di(O,O-di(dodecyl) dithiophosphate- S,S,) salt, di[O,O-di(dodecylphenyl)dithiophosphate]-S,S- salt, diethyldithiophosphate ammonium salt, dithiophosphate (O,O-isobutyl and pentyl) ester salt, dithiophosphate-O,O-diisooctyl ester salt, (T-4)-di[O-hexylO-(6-methylheptyl)dithiophosphate]- salt, di[O-(2-ethylhexyl)-O-(2-methylpropyl)dithiophosphate] salt, (T-4)-di(O,O-bis2-ethylhexyldithiophosphate-S,S) salt, dithiophosphate-O,O-di(hexyl and isobutyl) (T-4)-bis[O,O-bis(1-methylethyl)dithiophosphate-S,S'] salt, (T-4)-bis[O,O-bis(1,3-dimethylbutyl)dithiophosphate-SS]- salt, dithiophosphate-O,O-bis(sec-butyl and 1,3-dimethylbutyl) mixed ester salt, dipropoxydithiophosphate dibutyl succinate, O,O-bisdodecyl dithiophosphate hydrogen ester, O-ethylO-(4-methylthiophenyl)S-propyl dithiophosphate, S-(dimethylformamide methyl)O,O-dimethyl dithiophosphate;

[0118] The salts mentioned above include metal salts and ammonium salts.

[0119] From the above three embodiments, it can be concluded that wet sulfurization followed by PCD deposition of a wide-bandgap sulfur oxide protective film on the resonant cavity surface of a semiconductor laser can effectively improve the semiconductor laser device's resistance to COMD, thus ensuring the lifespan of the semiconductor laser device. Besides the uniqueness of the process, this also demonstrates the superiority of the passivation film material and structure. Furthermore, this passivation film material and structure can also be fabricated using other methods. For example, the passivation layer can be generated using plasma sulfurization, followed by plasma deposition of the sulfur oxide protective layer. However, this process is slightly more complex, increasing the complexity of the process and the risk of sulfur volatilization in the passivation layer, leading to a decrease in laser performance. Another method is to form the passivation layer using wet sulfurization, followed by sulfur oxide as a protective layer using methods such as CBD or electroplating. Theoretically, combining these methods can produce a passivation film very similar to that disclosed in this application, but the process simplicity and cost are not as good as the technology disclosed in this application.

[0120] In this embodiment, after forming a passivation layer on the resonant cavity surface of the semiconductor laser device, a protective layer is then applied over the passivation layer. The protective layer is made of a wide-bandgap sulfur oxide material, which prevents the passivation effect from failing due to oxidation or volatilization of the passivation layer on the resonant cavity surface. The passivation film on the resonant cavity surface of the semiconductor laser device in this application mainly serves two purposes: passivation effect and stability. Choosing a wide-bandgap sulfur oxide material as the protective layer material prevents the protective layer material from absorbing laser photons, prevents oxidation or volatilization of the passivation layer material, prevents passivation layer material failure, and improves the semiconductor laser device's resistance to COMD. In this way, the passivation film on the resonant cavity surface can remain effective for a long time, thereby ensuring the reliability of the semiconductor laser device and extending its service life. Furthermore, the passivation layer and the protective layer are formed in the same sulfur-containing compound solution, which simplifies the fabrication process and improves the fabrication efficiency of the passivation film on the resonant cavity surface.

[0121] In summary, the resonant cavity surface passivation technology for semiconductor laser devices in this application combines wet sulfide passivation and photochemical deposition (PCD) of wide-bandgap sulfide oxide thin films. PCD is a region-selective deposition method where the formed sulfide oxide film only occurs in the ultraviolet-irradiated area, i.e., the resonant cavity surface of the semiconductor laser device. The innovation of this application lies in using a solution for both wet sulfide passivation and PCD processes. The semiconductor laser device is first immersed in this solution to undergo a sulfide passivation reaction at the resonant cavity surface. Then, an ultraviolet lamp is turned on, initiating the PCD reaction and performing region-selective deposition of the protective layer to form a passivation film. This resonant cavity surface passivation film technology is a novel method for effectively resisting COMD in semiconductor laser devices. Although the embodiments of this application disclose the use of an ultraviolet lamp, lasers with ultraviolet wavelengths also achieve the same effect. However, ultraviolet laser equipment is much more expensive than ultraviolet lamps, which is detrimental to production costs.

[0122] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A passivation film on the resonant cavity surface of a semiconductor laser device, characterized in that, The resonant cavity surface passivation film includes: A passivation layer is applied to the resonant cavity surface of a semiconductor laser device. A protective layer is provided on top of the passivation layer. The protective layer is made of a wide bandgap sulfur oxide material. The bandgap width of the wide bandgap sulfur oxide material is greater than the laser photon energy. The passivation layer and the protective layer are formed in the same sulfur-containing compound solution, comprising: The prepared bar is immersed in the sulfur-containing compound solution and wet-cured on the resonant cavity surface of the semiconductor laser device to form a passivation layer; wherein, the wet curing process is carried out without ultraviolet light irradiation, and after the wet curing is completed, the passivation layer has a thickness of several atomic layers to tens of atomic layers. An ultraviolet light source is turned on to perform a photochemical deposition reaction, and a protective film is deposited on the passivation layer; wherein, the sulfur-containing compound solution contains thiosulfate ions (S2O3). 2- ), thiosulfonate (R-S2O2) - ), thiophosphate (SPO3) 3- ) or dithiophosphate (S2PO2) 3- At least one of the following can be used as a source of sulfur in the passivation layer and the wide-bandgap sulfur oxide material:

2. The resonant cavity surface passivation film according to claim 1, characterized in that, The passivation layer is a sulfur-containing thin film formed by reacting the resonant cavity surface semiconductor epitaxial material of the semiconductor laser device with a sulfur-containing compound; the thickness of the passivation layer is several to tens of atomic layers.

3. The resonant cavity surface passivation film according to claim 1, characterized in that, The thickness of the protective layer is 1-800 nm; the protective layer is a component or all of the subsequent resonant cavity surface optical thin film.

4. The resonant cavity surface passivation film according to claim 1, characterized in that, The wide-bandgap sulfur oxide material includes: At least one of them, wherein the range of m is: 0.2 ≥ m >

0.

5. The resonant cavity surface passivation film according to claim 1, characterized in that, The protective layer is a mixture of wide-bandgap sulfur oxide materials, which contains at least two or more metal ions to form two or more sulfur oxides.

6. The resonant cavity surface passivation film according to claim 5, characterized in that, The wide-bandgap sulfur oxide material mixture includes the following sulfur oxides. A mixture of two or more substances, wherein the range of m is: 0.2 ≥ m >

0.

7. The resonant cavity surface passivation film according to claim 1, characterized in that, The protective layer is made of a wide-bandgap sulfur oxide alloy, which contains at least two or more metal ions to form a single sulfur oxide.

8. The resonant cavity surface passivation film according to claim 7, characterized in that, The alloy materials of the wide-bandgap sulfur oxides include: At least one of the following, wherein the ranges of x and y are: 1 > x, y > 0, and the range of m is: 0.2 ≥ m > 0.

9. A semiconductor laser device, characterized in that, The semiconductor laser device includes a resonant cavity surface passivation film, which is the resonant cavity surface passivation film as described in any one of claims 1-8.

10. A method for fabricating a passivation film on the resonant cavity surface of a semiconductor laser device, characterized in that, The method includes: The prepared bar is immersed in a sulfur-containing compound solution and wet-cured on the resonant cavity surface of the semiconductor laser device to form a passivation layer; wherein, the wet curing process is carried out without ultraviolet light irradiation, and after the wet curing is completed, the thickness of the passivation layer is from several atomic layers to tens of atomic layers. An ultraviolet light source is turned on to perform a photochemical deposition reaction, and a protective film is coated on the passivation layer. The material of the protective layer is a wide bandgap sulfur oxide material; the bandgap width of the wide bandgap sulfur oxide material is greater than the laser photon energy. The passivation layer and the protective layer are formed in the same sulfur-containing compound solution; wherein the sulfur-containing compound solution contains thiosulfate ions (S₂O₃). 2- ), thiosulfonate (R-S2O2) - ), thiophosphate (SPO3) 3- ) or dithiophosphate (S2PO2) 3- At least one of the following can be used as a source of sulfur in the passivation layer and the wide-bandgap sulfur oxide material:

11. The manufacturing method according to claim 10, characterized in that, The solvent for the sulfur-containing compound solution is water or an organic solvent, or a mixture of water and an organic solvent.

12. The manufacturing method according to claim 10, characterized in that, The raw materials used in the sulfur-containing compound solution include at least one of the following substances: 1) Thiosulfate (S2O3) 2- Class ) : Thiosulfate or thiosulfate; 2) Thiosulfonate (R-S2O2) - Class 1: Ethyl thiosulfonate, Methyl thiosulfonate, Thiobenzene sulfonate, 4-Toluene thiosulfonate, p-Toluene thiosulfonic acid, S-Benzylmethane thiosulfonate, 2-Aminoethyl thiosulfonic acid, Propylmethane thiosulfonate, Amylmethane thiosulfonate, (3-Sulfopropyl)methane thiosulfonate, 1,2-Ethyldimethylmethane thiosulfonate, 2-Aminoethylmethane thiosulfonate, 5-Aminopentylmethane thiosulfonate, S,S'-[1,2-Ethyldimethyldi(oxy-2,1-ethylenediyl)]dimethylmethane thiosulfonate. 3) Thiophosphate (SPO3) 3- Class: Thiophosphates, dimethyl thiophosphate salts, n-butyl thiophosphate triamine, O,O-dimethyl thiophosphate or salts, O,o-diethyl-o-hydrothiophosphate, O,O-dimethyl thiophosphate, potassium diethyl thiophosphate, O,O-diisopropyl thiophosphate, trimethyl thiophosphate, O,O,O-triethyl thiophosphate, O,O,O-triphenyl thiophosphate, 4-aminophenol thiophosphate, O,O-dimethyl thiophosphate, O,O-diethyl thiophosphate, N,N',N''-trimethyl thiophosphate triamide, dimethyl monothiophosphate, O,O-dimethyl-O-(2-ethylthioethyl) thiophosphate, O-2,4-dichlorophenyl-O,O-diethyl thiophosphate, 2-isopropyl-4-methyl-6-pyrimidinyl thiophosphate diethyl ester; 4) Dithiophosphate (S2PO2) 3- Class: Dithiophosphate, diisobutyl dithiophosphate, O-m-tolyl-O-p-tolyl dithiophosphate, xylenol dithiophosphate, dimethyl dithiophosphate, O,O-dimethyl dithiophosphate, dithiophosphate-O,O-di(1-methylpropyl) ester, dialkyl dithiophosphate, O,O-dibutyl dithiophosphate, O,O-bis(1,3-dimethylbutyl) dithiophosphate, toluene dithiophosphate, diethyl dithiophosphate, diethyl dithiophosphate, diisopropyl dithiophosphate, dithiophosphate-O,O -Di(1-methylethyl) ester, O-ethyl-S-propyl dithiophosphate, O,O-dimethyl dithiophosphate, O,O'-diethyl dithiophosphate, O,O-diethyl dithiophosphate salt, O,O-diethyl-S-propyl dithiophosphate, dimethoxydithiophosphate methyl acetate, O,O-phenyl dithiophosphate, dimethylphenol dithiophosphate, di(O,O-diisodecyl dithiophosphate-S,S')- salt, di(tetrapropylenephenol) dithiophosphate salt, di(O,O-di(dodecyl) dithiophosphate- S,S,) salt, di[O,O-di(dodecylphenyl)dithiophosphate]-S,S- salt, diethyldithiophosphate ammonium salt, dithiophosphate (O,O-isobutyl and pentyl) ester salt, dithiophosphate-O,O-diisooctyl ester salt, (T-4)-di[O-hexylO-(6-methylheptyl)dithiophosphate]- salt, di[O-(2-ethylhexyl)-O-(2-methylpropyl)dithiophosphate] salt, (T-4)-di(O,O-bis2-ethylhexyldithiophosphate-S,S) salt, dithiophosphate-O,O-di(hexyl and isobutyl) (T-4)-bis[O,O-bis(1-methylethyl)dithiophosphate-S,S'] salt, (T-4)-bis[O,O-bis(1,3-dimethylbutyl)dithiophosphate-SS]- salt, dithiophosphate-O,O-bis(sec-butyl and 1,3-dimethylbutyl) mixed ester salt, dipropoxydithiophosphate dibutyl succinate, O,O-bisdodecyl dithiophosphate hydrogen ester, O-ethylO-(4-methylthiophenyl)S-propyl dithiophosphate, S-(dimethylformamide methyl)O,O-dimethyl dithiophosphate; The above salts include metal salts and ammonium salts.

13. The manufacturing method according to claim 10, characterized in that, The sulfur-containing compound solution used in the fabrication of the resonant cavity surface passivation film contains at least one of the following elements' ions or complex ions: zinc, cadmium, magnesium, calcium, strontium, barium, aluminum, gallium, indium, tin, antimony, bismuth, or manganese ions or complex ions, as the source of the cationic components in the protective layer.

14. The manufacturing method according to claim 10, characterized in that, The photochemical deposition reaction is carried out by irradiating the resonant cavity surface of the semiconductor laser device with ultraviolet light, and the ultraviolet light irradiation method is continuous irradiation or intermittent irradiation.

15. The manufacturing method according to claim 10, characterized in that, The wavelength of the ultraviolet light is less than 400 nm.

16. The manufacturing method according to claim 10, characterized in that, The ultraviolet light source includes at least one of the following: Ar2*, Kr2*, Xe2*, F2*, Cl2*, Br2*, I2*, NeF*, ArF*, ArCl*, ArBr*, KrF*, KrCl*, KrBr*, KrI*, XeF*, XeCl*, XeBr*, XeI* excimer lamps, mercury lamps, xenon lamps, hydrogen arc lamps, carbon arc lamps, metal halide lamps, ultraviolet light-emitting diodes, and ultraviolet lasers.

17. The manufacturing method according to claim 10, characterized in that, The source of the ultraviolet light includes: a UV-B ultraviolet lamp.

18. The manufacturing method according to claim 10, characterized in that, The ultraviolet light source includes at least one of the following: mercury-xenon lamp, deuterium arc lamp, and xenon-antimony arc lamp.

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