WO2019184064A1 - Semiconductor laser device and resonant cavity surface passivation film thereof, and manufacturing method - Google Patents

Abstract

A semiconductor laser device and a resonant cavity surface passivation film (100) thereof, and a manufacturing method. The resonant cavity surface passivation film (100) comprises: a passivation layer (101), directly covering a resonant cavity surface of a semiconductor laser device; and a protective layer (102), covering the passivation layer (101), wherein the protective layer (102) is made of wide-bandgap semiconductor materials formed by chemical bath deposition. By means of this method, the resonant cavity surface passivation film (100) is valid for a long time, the capability of a semiconductor laser device to resist catastrophic optical mirror damage can be improved, and the maximum output power of the semiconductor laser device can be increased, thus ensuring the reliability of the semiconductor laser device and prolonging the service life of the semiconductor laser device.

Description

Semiconductor laser device and resonant cavity surface passivation film thereof, and manufacturing method thereof [Technical Field]

The present application relates to the field of semiconductor surface passivation technology, and in particular to a semiconductor laser device and a resonant cavity surface passivation film thereof.

【Background technique】

Catastrophic optical mirror damage (COMD) is an important factor affecting the reliability, lifetime and maximum output power of semiconductor lasers. After the resonant cavity surface is irradiated by the strong light in the cavity, the electrons and holes are non-radiatively compounded on the cavity surface, the temperature rises, and the temperature increases, the band gap of the material decreases, thereby accelerating the cavity facing the laser. Absorbing, and accelerating the oxidation of the cavity surface and the diffusion of defects, oxidation leads to an increase in the surface state density of the cavity surface, accelerating the induction of non-radiative recombination of the cavity surface region, which forms a positive feedback process, when the cavity When the surface temperature exceeds the melting point of the material, the cavity surface is melted, and the semiconductor laser device is completely ineffective.

The cavity surface passivation technology of semiconductor lasers is one of the effective methods to mitigate the damage of catastrophic optical mirrors, which can improve the reliability and extend the service life of semiconductor lasers. In the prior art, the most successful passivation technique for mitigating the catastrophic phenomenon of the cavity surface is to dissociate the bar in the ultra-high vacuum and plate the silicon on the cavity surface, but this method is not easy to operate, expensive, and low in productivity, so It is necessary to dissociate the bar in the atmospheric environment and then perform the technique of cavity surface passivation. The vulcanization method is a method for removing the surface oxides and surface defects of the III-V compound semiconductor, and can effectively improve the threshold of the catastrophic optical mirror damage of the semiconductor laser device.

The inventors of the present application found in the long-term development process that wet vulcanization is simple and easy to use, and the cost is low, and the application is extensive, but the wet vulcanization has such a problem that blunt formation on the cavity surface by wet vulcanization is formed. The film is easily reoxidized or easily volatilized, thereby causing the passivation of the passivation film to fail.

[Summary of the Invention]

The technical problem mainly solved by the present application is to provide a semiconductor laser device and a resonant cavity surface passivation film thereof, and a manufacturing method thereof, which can make the resonant cavity surface passivation film effective for a long time, thereby ensuring the reliability of the semiconductor laser device and extending the semiconductor. The life of the laser device.

In order to solve the above technical problem, a technical solution adopted by the present application is to provide a resonant cavity surface passivation film of a semiconductor laser device, the resonant cavity surface passivation film comprising: a passivation layer covering a resonance of a semiconductor laser device a cavity surface; a protective layer covering the passivation layer, wherein the protective layer is a film formed by chemical bath deposition, and the material of the protective layer is a wide band gap semiconductor material.

In order to solve the above technical problem, another technical solution adopted by the present application is to provide a semiconductor laser device including a cavity surface passivation film, and the cavity surface passivation film is a cavity surface as above. Passivation film.

In order to solve the above technical problem, another technical solution adopted by the present application is to provide a method for fabricating a resonant cavity surface passivation film of a semiconductor laser device, the method comprising: covering a cavity surface of the semiconductor laser device with a blunt layer a film of a layer; a film of a protective layer is coated on the passivation layer by chemical bath deposition, and the material of the protective layer is a wide band gap semiconductor material.

The beneficial effects of the present application are: different from the prior art, the resonant cavity surface passivation film of the present application includes: a passivation layer covering the resonant cavity surface of the semiconductor laser device; and a protective layer covering the passivation layer The protective layer is formed by a chemical bath deposition method, and the material of the protective layer is a wide band gap semiconductor material. The function of the passivation layer process includes two aspects: (1) removing surface oxides and surface defects caused by contact with air on the cavity surface; (2) depositing a dense passivation layer on the cavity surface, the passivation layer The material saturates the cavity surface dangling bonds. The cavity surface passivation technology of the semiconductor laser device of the present application combines a method of wet vulcanization passivation and chemical bath deposition of a wide band gap sulfide film, which is a new semiconductor laser device effective resistance The method of catastrophic optical mirror damage can make the resonant cavity surface passivation film effective for a long time, thereby ensuring the reliability of the semiconductor laser device and prolonging the service life of the semiconductor laser device.

[Description of the Drawings]

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings used in the description of the embodiments will be briefly described below. It is obvious that the drawings in the following description are only some embodiments of the present application. Other drawings may also be obtained from those of ordinary skill in the art in light of the inventive work. among them:

1 is a schematic structural view of an embodiment of a cavity surface passivation film of a semiconductor laser device provided by the present application;

2 is a schematic structural view of an embodiment of a semiconductor laser device provided by the present application;

3 is a schematic flow chart of an embodiment of a method for fabricating a resonant cavity surface passivation film of a semiconductor laser device of the present application;

Fig. 4 is a schematic view showing a single-tube laser chip fabricated by wet-vulcanization passivation of a cavity surface of a laser chip and then immediately depositing a wide-band gap sulfide film by a chemical bath deposition method.

【detailed description】

The technical solutions in the embodiments of the present application will be clearly and completely described in the following with reference to the accompanying drawings in the embodiments. It is understood that the specific embodiments described herein are merely illustrative of the application and are not intended to be limiting. In addition, it should be noted that, for the convenience of description, only some but not all of the structures related to the present application are shown in the drawings. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present application without departing from the inventive scope are the scope of the present application.

The terms "first", "second", and the like in this application are used to distinguish different objects, and are not intended to describe a particular order. Furthermore, the terms "comprises" and "comprising" and "comprising" are intended to cover a non-exclusive inclusion. For example, a process, method, system, product, or device that comprises a series of steps or units is not limited to the listed steps or units, but optionally also includes steps or units not listed, or alternatively Other steps or units inherent to these processes, methods, products or equipment.

References to "an embodiment" herein mean that a particular feature, structure, or characteristic described in connection with the embodiments can be included in at least one embodiment of the present application. The appearances of the phrases in various places in the specification are not necessarily referring to the same embodiments, and are not exclusive or alternative embodiments that are mutually exclusive. Those skilled in the art will understand and implicitly understand that the embodiments described herein can be combined with other embodiments.

Before describing the present application in detail, the state of the art related to the present application will be described.

The cavity surface passivation technology of semiconductor lasers is one of the effective methods to mitigate the damage of catastrophic optical mirrors, which can improve the reliability and extend the service life of semiconductor lasers. The most successful passivation technique for mitigating the catastrophic phenomenon of the resonant cavity surface in the prior art is to dissociate the strip in the ultra-high vacuum and plate the silicon on the cavity surface, but this method is not easy to operate, expensive, and low in productivity, so it is required The technique of dissociating the bar in the atmospheric environment and then performing passivation of the cavity surface. The main principles of the cavity surface passivation technology after the atmosphere is dissociated from the strip include two aspects: firstly, the surface oxide and surface defects generated by the contact of the cavity surface with the air are removed, usually by wet or dry method. Secondly, a dense dielectric film is deposited on the cavity surface, and the saturated cavity surface is dangling bonds, usually by physical vapor deposition or chemical vapor deposition.

The vulcanization method is a method for removing the surface oxides and surface defects of the III-V compound semiconductor, and can effectively improve the threshold of the catastrophic optical mirror damage of the semiconductor laser device. The vulcanization method includes wet vulcanization and dry vulcanization. Most of the reports are wet vulcanization, mainly using a sulfur-containing solution and a semiconductor reaction, while dry vulcanization is a treatment of a semiconductor using a sulfur-containing plasma. The wet vulcanization of the resonant cavity surface of a semiconductor laser refers to immersing the cavity surface in a sulfur-containing compound solution, for example, an aqueous solution of ammonium sulfide ((NH ₄ ) ₂ S) or an organic alcohol solution, sodium sulfide (Na ₂ S). An aqueous solution or an organic alcohol solution to remove the native oxide and surface defects of the cavity surface, and then form a sulfide passivation layer on the surface of the cavity, that is, a film after the vulcanization reaction. Although wet vulcanization is simple in operation and low in cost, the following problems exist:

The passivation method in the vulcanization method is the sulfide and sulfur of several atomic layers to tens of atomic layers on the surface of the resonant cavity. After the cavity surface is left in the air for a period of time, the sulfur will oxidize or volatilize, so that the cavity surface The semiconductor material is reoxidized and the passivation is thus disabled. Even if the laser chip after vulcanization of the cavity surface is taken out from the solution, and quickly placed in the coating equipment after drying, the subsequent deposition of the optical film on the cavity surface is still highly probable, causing the vulcanization of the cavity surface to be invalid because of the optics. The deposition of the film is usually carried out under vacuum and/or heating at a high temperature, and this environment is more likely to cause volatilization of sulfur, resulting in ineffective passivation of the wet vulcanization.

The present invention is coated with a passivation layer on the cavity surface of the semiconductor laser device, and then covered with a protective layer on the passivation layer by chemical bath deposition. The material of the protective layer is a wide band gap semiconductor material, which can prevent the cavity surface. The sulfur disappeared. The function of the cavity surface passivation film of the semiconductor laser device of the present application mainly includes two aspects, namely, a passivation effect and stability thereof. Selecting a wide-bandgap semiconductor material as a protective layer material can prevent the absorption of the laser by the protective layer material and prevent the failure of the passivation layer material. In this way, the resonant cavity surface passivation film can be made effective for a long time, thereby ensuring the semiconductor laser. The reliability of the piece extends the life of the semiconductor laser device.

The present application will be described in detail below with reference to the accompanying drawings and embodiments.

Referring to FIG. 1 , FIG. 1 is a schematic structural view of an embodiment of a resonant cavity surface passivation film of a semiconductor laser device of the present application. The cavity surface passivation film 100 includes a passivation layer 101 and a protective layer 102 .

The passivation layer 101 covers the resonant cavity surface of the semiconductor laser device; the protective layer 102 covers the passivation layer 101, and the material of the protective layer 102 is a wide band gap semiconductor material.

In this embodiment, the material of the passivation layer 101 may be a material used for the cavity surface passivation of the semiconductor laser device in the prior art; the process of covering the cavity surface of the semiconductor laser device with the passivation layer 101 may be It is a process for forming a cavity surface passivation layer of a semiconductor laser device in the prior art. For example, the material of the passivation layer 101 may be a sulfide film, which may be formed by a wet process or a dry process; for example, a cavity surface passivation formed after the atmosphere is dissociated from the bar Layer; and so on.

Semiconductor materials with a band gap greater than 2.0 eV at room temperature are generally classified as wide bandgap semiconductor materials. Wide bandgap semiconductor materials are widely used in blue, violet and ultraviolet optoelectronic devices, high frequency, high temperature, high power electronic devices and field emission devices. Wide bandgap semiconductor materials include, but are not limited to, zinc oxide, sulfide, gallium nitride, silicon carbide, and the like. Specifically, the band gap energy of the wide band gap semiconductor material is greater than the photon energy of the laser light, and therefore, the absorption of the laser light by the protective layer material can be prevented.

In practical applications, the film of the wide bandgap semiconductor material of the protective layer 102 may be part of the resonant cavity surface optical film of the subsequent semiconductor laser device or all of it as a component of the cavity surface optical film of the semiconductor laser device, complete blunt The film 100 can be further plated with other material films to adjust the reflectivity to achieve the characteristics of the semiconductor laser device design. For example, the SiO ₂ and TiO ₂ films are plated on one end of the semiconductor laser device so that the entire protective layer 102 is included. The reflectance is 1%, and the other end is plated with a SiO ₂ and TiO ₂ multilayer film structure such that the overall reflectance of the protective layer 102 is 99%. The above optical coating is such that the passivation layer 101 is not affected by the presence of the protective layer 102. Subsequent coating process effects are degraded.

In the embodiment of the present application, after the resonant cavity surface of the semiconductor laser device is covered with a passivation layer 101, the passivation layer 101 is immediately covered with a protective layer 102. The material of the protective layer 102 is a wide band gap semiconductor material. Failure of the passivation layer 101 of the cavity face is prevented. The function of the cavity surface passivation film 100 of the semiconductor laser device of the present application mainly includes two aspects, namely, a passivation effect and stability thereof. Selecting to deposit a wide bandgap semiconductor material as the material of the protective layer 102 immediately can prevent oxidation or volatilization of the material of the passivation layer 101, prevent material failure of the passivation layer 101, and prevent absorption of laser photons by the material of the protective layer 102. In this way, the cavity surface passivation film 100 can be made effective for a long time, thereby ensuring the reliability of the semiconductor laser device and prolonging the service life of the semiconductor laser device.

In one embodiment, the passivation layer 101 is a sulfide and sulfur thin film formed by reacting a cavity surface of a semiconductor laser device with a sulfur-containing compound.

The sulfide film formed by the reaction of the cavity surface of the semiconductor laser device with the sulfur-containing compound may be formed by a dry process or a wet process. More reported are wet vulcanization, mainly using sulfur-containing compound solutions and semiconductor reactions, while dry vulcanization is the treatment of semiconductors using sulfur-containing plasma. The wet vulcanization of the cavity surface of a semiconductor laser device refers to immersing the cavity surface in a sulfur-containing compound solution, for example, an aqueous solution of ammonium sulfide ((NH ₄ ) ₂ S) or an organic alcohol solution, sodium sulfide (Na _{2 )} An aqueous solution or an organic alcohol solution of S) to remove the native oxide and surface defects of the cavity surface, and then form a sulfide passivation layer on the cavity surface, that is, a sulfide film after the sulfurization reaction. Specifically, the sulfur-containing compound solution contains at least a sulfide solution of one of ammonium sulfide, lithium sulfide, sodium sulfide, potassium sulfide, magnesium sulfide, calcium sulfide, barium sulfide, barium sulfide, thiourea or thioacetamide. The solvent is water or an organic solution, or a mixed solution of water and an organic solution.

The thickness of the passivation layer 101 is from several atomic layers to several tens of atomic layer thicknesses.

In one embodiment, the material of the protective layer 102 is a wide band gap sulfide semiconductor 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, 800 nm, and the like.

In the present embodiment, the material of the protective layer 102 is selected as a wide band gap sulfide semiconductor material, on the one hand, the absorption of the laser photon by the material of the protective layer 102 can be prevented, the oxidation or volatilization of the material of the passivation layer 101 is prevented, and the passivation layer 101 Both the material and the protective layer 102 are sulfides, and the materials are matched with each other; on the other hand, the sulfide semiconductor material is used as the material of the protective layer 102, and the forming process of the material can be matched with the process of the sulfide passivation layer, that is, Both processes are completed in a sulfur-containing solution.

In a specific embodiment, the wet process deposits a film of sulfide film including Chemical Bath Deposition (CBD), Photochemical Deposition (PCD), and the like. Among them, the chemical bath deposition method has the advantages of simple process, low cost, no need for a vacuum device, easy control of experimental conditions, and easy integration with the wet vulcanization process. The pH of the solution in the chemical bath deposition system, the temperature, the type of complexing agent, the type of additives, etc. will affect the deposition rate, oxygen content, stress state, transmittance, adhesion, surface morphology, etc. of the wide band gap sulfide film. . As long as the appropriate solution formulation and parameters are used, the chemical bath deposition of the wide band gap sulfide film can achieve high deposition rate, low oxygen content, low stress, high transmittance, strong adhesion, and uniform film coverage.

Among them, the chemical bath used in the chemical bath deposition method contains thiosulfate ion (S ₂ O ₃ ^2- ) as a source of sulfur of the wide band gap sulfide. In addition, the chemical solution also contains at least one of ions of zinc, cadmium, copper, magnesium, calcium, strontium, barium, boron, aluminum, gallium, indium or tin, or a mixture of a plurality of ions, or may be A complex ion composed of atoms to form a different wide band gap sulfide film. It can be understood that the mixture formed by a plurality of ions means that two or more kinds of cations are contained in the chemical solution, and the cations may be zinc, cadmium, copper, magnesium, calcium, barium, strontium, boron, aluminum, or the like. The ion, the type and the ratio of the cations contained in the gallium, indium or tin can be arbitrarily set as needed, and are not limited herein.

Optionally, in an embodiment, the wide band gap sulfide semiconductor material specifically includes: Zn(S _1-δ O _δ ), Cd(S _1-δ O _δ ), Cu(S _1-δ O _δ ), Cu ₂ (S _1-δ O _δ ), Mg(S _1-δ O _δ ), Ca(S _1-δ O _δ ), Sr(S _1-δ O _δ ), Ba(S _1-δ O _δ ), B ₂ (S _1-δ O _δ ) ₃ , Al ₂ (S _1-δ O _δ ) ₃ , Ga ₂ (S _1-δ O _δ ) ₃ , In ₂ (S _1-δ O _δ ) ₃ , Sn ( At least one of S _1-δ O _δ ) ₂ , that is, the wide band gap sulfide semiconductor material may be the above-mentioned materials alone or a mixture of two or more materials, wherein δ represents a sulfide semiconductor material. The content of oxygen atoms in the middle, and the range of δ is: 0.2 ≥ δ ≥ 0. For example: ZnS (δ = 0), Cd (S _0.9 O _0.1 ), CuS (δ = 0), Cu ₂ (S _0.95 O _0.05 ), Mg (S _0.9 O _0.1 ), Ca (S _0.95 O _0.05 ), Sr (S _0.98 O _0.02 ), Ba (S _0.88 O _0.12 ), B ₂ (S _0.85 O _0.15 ) ₃ , Al ₂ (S) ₃ (δ = 0), Ga ₂ (S) ₃ (δ = 0), In ₂ (S _0.97 O _0.03 ) ₃ , Sn(S _0.92 O _0.08 ) ₂ , and so on.

Further, the material of the protective layer 102 is a mixture containing a wide band gap sulfide semiconductor material; for example, a mixture containing a wide band gap sulfide semiconductor material includes: Zn(S _1-δ O _δ ) and Cd(S _1-ξ O _ξ ) Mixture, a mixture of Cu(S _1-δ O _δ ) and Cu ₂ (S _1-ξ O _ξ ), a mixture of Zn(S _1-δ O _δ ) and Mg(S _1-δ O _δ ), Mg( a mixture of 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 ), Al ₂ (S _1-δ O a mixture of _δ ) ₃ and Ga ₂ (S _1-ξ O _ξ ) _{3 ,} a mixture of Al ₂ (S _1-δ O _δ ) ₃ and Mg(S _1-ξ O _ξ ), Cu ₂ (S _1-δ O At least one of a mixture of _δ ) and Sn(S _1-ξ O _ξ ) ₂ , that is, a mixture containing a wide band gap sulfide semiconductor material may be one of the above-mentioned mixtures, or may be two or more of the above The material of the mixture. Where δ represents the content of oxygen atoms in a sulfide semiconductor material in the mixture, and ξ represents the content of oxygen atoms in another sulfide semiconductor material in the mixture, and the ranges of δ and ξ are: 0.2 ≥ δ ≥ 0 and 0.2 ≥ Ξ≥0; for example: a mixture containing a wide band gap sulfide semiconductor material is a mixture of Zn(S _1-δ O _δ ) and Cd(S _1-ξ O _ξ ); it may also be Zn(S _1-δ O _δ ) a mixture of a mixture of Al ₂ (S _1-δ O _δ ) ₃ and Mg (S _1-δ O _δ ), and the like.

Further, the material of the protective layer 102 is an alloy semiconductor material of a wide band gap sulfide; for example, an alloy semiconductor material of a wide band gap sulfide includes: (Zn _1-x Cd _x )(S _1-δ O _δ ), (Zn _{1- Xy} Cd _x Cu _y )(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-xy Ca _x Ba _y )(S _1-δ O _δ ), (Al _1-x Ga _x ) ₂ (S _1-δ O _{At least one of δ} ) ₃ , (Sn _1-x Cu _x )(S _1-δ O _δ ) ₂ , Cu ₄ Sn(S _1-δ O _δ ) ₄ , that is, an alloy of a wide band gap sulfide The semiconductor material may be one of the above alloy semiconductor materials, or may be a mixture of two or more of the above alloy semiconductor materials. Where x is the content of a metal in an alloy semiconductor material of a wide band gap sulfide (alloy semiconductor material of two metals), and y is an alloy semiconductor material of a wide band gap sulfide (alloy semiconductor material of three metals) The content of another metal, δ represents the content of oxygen atoms in the sulfide semiconductor material, and the range of x and y is: 1 ≥ x, y ≥ 0, and the range of δ is: 0.2 ≥ δ ≥ 0.

Taking ZnS as an example of a wide band gap sulfide, the band gap width of ZnS is 3.54 eV (electron volt). According to the different preparation conditions, the optical band gap of the chemical bath deposited ZnS film is 3.7-4.2eV, and the optical band gap is wide because the film deposited by the chemical bath has small crystal particles, based on the principle of quantum confinement. The optical band gap is wider than that of the bulk material. The characteristics of the wide band gap do not intrinsic absorption of the emission wavelength of the semiconductor laser (for example, greater than 600 nm), and the chemical bath deposited ZnS film contains a small amount of oxygen. Oxygen does not affect the passivation effect of the resonant cavity surface of the laser chip.

Different from the prior art, the cavity surface passivation film of the embodiment includes: a passivation layer covering the cavity surface of the semiconductor laser device; and a protective layer covering the passivation layer, the protective layer A film is formed by chemical bath deposition, and the material of the protective layer is a wide band gap semiconductor material. The function of the passivation layer process includes two aspects: (1) removing surface oxides and surface defects caused by contact with air on the cavity surface; (2) depositing a dense passivation layer on the cavity surface, the passivation layer The material saturates the cavity surface dangling bonds. The cavity surface passivation technology of the semiconductor laser device of the present application combines a method of wet vulcanization passivation and chemical bath deposition of a wide band gap sulfide film, which is a new semiconductor laser device effective resistance The method of catastrophic optical mirror damage can make the resonant cavity surface passivation film effective for a long time, thereby ensuring the reliability of the semiconductor laser device and prolonging the service life of the semiconductor laser device.

Referring to FIG. 2, FIG. 2 is a schematic structural view of an embodiment of a semiconductor laser device according to the present application. The semiconductor laser device 200 includes a cavity surface passivation film 100, and the cavity surface passivation film 100 is a cavity surface passivation film of any of the above. . For a detailed description of the related content, please refer to the detailed description of the above-mentioned cavity surface passivation film 100, which will not be described herein.

Referring to FIG. 3, FIG. 3 is a schematic flow chart of an embodiment of a method for fabricating a resonant cavity surface passivation film of a semiconductor laser device according to the present application, which can fabricate a resonant cavity surface passivation film of the above semiconductor laser device, and a detailed description thereof Please refer to the above-mentioned cavity surface passivation film of the semiconductor laser device, which will not be described here.

The method includes: step S31 and step S32.

Step S31: covering a cavity surface of the semiconductor laser device with a film of a passivation layer.

Step S32: The passivation layer is covered with a protective layer film by chemical bath deposition, and the material of the protective layer is a wide band gap semiconductor material.

In the embodiment of the present application, after the resonant cavity surface of the semiconductor laser device is covered with a passivation layer, the passivation layer is covered with a protective layer by chemical bath deposition, and the material of the protective layer is a wide band gap semiconductor material. It is possible to prevent the failure of the passivation caused by the oxidation or volatilization of the passivation layer of the cavity surface. The role of the cavity surface passivation film of the conductor laser device of the present application mainly includes two aspects, namely, a passivation effect and stability thereof. Selecting a wide bandgap semiconductor material as a protective layer material can prevent the absorption of laser photons by the protective layer material, prevent oxidation or volatilization of the passivation layer material, and prevent the passivation layer material from failing. In this way, the cavity surface can be made blunt The film is effective for a long time, thereby ensuring the reliability of the semiconductor laser device and prolonging the service life of the semiconductor laser device.

The step S31 may specifically include: reacting a resonant cavity surface of the semiconductor laser device with a sulfur-containing solution to form a film containing sulfur and sulfide covering the surface of the resonant cavity, the thickness of the passivation layer being a few atomic layers to Dozens of atomic layers. Wherein, the wet vulcanization method is used to form a passivation layer on the resonant cavity surface of the semiconductor laser device; the wet vulcanization method uses a sulfur-containing chemical solution, and the sulfur-containing chemical solution contains: ammonium sulfide, lithium sulfide, sodium sulfide, potassium sulfide a sulfide of at least one of magnesium sulfide, calcium sulfide, barium sulfide, barium sulfide, thiourea or thioacetamide; the solvent of the sulfur-containing chemical solution is water or an organic solvent, or a mixture of water and an organic solvent Solution.

The step S32 may specifically include: in the chemical bath deposition process, the chemical solution used contains thiosulfate ions as a source of sulfur of the wide band gap sulfide; the chemical solution further comprises: zinc, cadmium, copper, magnesium, calcium, At least one of ions or complex ions of ruthenium, osmium, boron, aluminum, gallium, indium or tin acts as a source of cations.

Wherein, the material of the protective layer is a wide band gap sulfide semiconductor material; the thickness of the protective layer is 1-800 nm.

Referring to FIG. 4, FIG. 4 is a schematic diagram of a single-tube laser chip fabricated by performing wet vulcanization passivation on a resonant cavity surface of a laser chip and then depositing a wide-band gap sulfide film by chemical bath deposition. The resonant cavity surface in the figure is respectively covered with the sulfide film 1 and the wide band gap sulfide film 2 after the vulcanization reaction, wherein the structure along the epitaxial growth direction comprises: an active layer 3, a waveguide layer 4, an n-type cladding layer 5, The p-type cladding layer 6, the semiconductor substrate 7, the n-plane metal electrode 8, the p-plane metal electrode 9, and the p-type heavily doped semiconductor layer 10. The active layer 3, the waveguide layer 4, and the cladding layers 5 and 6 and the semiconductor substrate 7 respectively correspond to different materials, for example, InGaP/[(AlxGa _1-x ) _1-y In _y ]P/ with a wavelength of 630-680 nm. In the [(AluGa _1-u ) _1-v In _v ]P/GaAs epitaxial system, the material of the active layer 3 is an InGaP quantum well, and the material of the waveguide layer 4 is [(Al _x Ga _1-x ) _1-y In _y ]P, the material of the cladding layers 5, 6 is [(Al _u Ga _1-u ) _1-v In _v ]P or AlInP, the composition of the material of the waveguide layer 4 and the cladding layers 5, 6 is different, the former The band gap width is small, the refractive index is large, and the material of the semiconductor substrate 7 is GaAs; and the wavelength is 1300-1700 nm [(Al _x Ga _1-x ) _1-y In _y ] As / [(Al _x Ga _{1 -x} ) _1-y In _y ]As/InP system, the material of the active layer 3 is [(Al _x Ga _1-x ) _1-y In _y ] As quantum well, and the material of the waveguide layer 4 is [(Al _u Ga _1-u ) _1-v In _v ]As, the material of the cladding layers 5 and 6 is InP, the material of the semiconductor substrate 7 is InP; the other is GaAsP/[(Al _x Ga _1-) having a wavelength of 750-900 nm. _x ) _1-y In _y ]P/[(Al _u Ga _1-u ) _1-v In _v ]P/GaAs epitaxial system, In(Al)GaAs/(Al _x Ga _1-x with a wavelength of 800-1100 nm As/(Al _y Ga _1-y )As/GaAs epitaxial system and GaAs/wavelength of 800-870 nm (Al _x Ga _1-x )As/(Al _y Ga _1-y )As/GaAs epitaxial system. The passivation layer can be effectively passivated by the wet vulcanization of the semiconductor laser cavity surface epitaxial material system of the above various bands, and the chemical bath deposition can also deposit the broadband on the above-mentioned vulcanized semiconductor laser cavity surface epitaxial material system. A slit sulfide film.

A specific embodiment will be described below to illustrate the process method of the present application and the passivation film and device prepared by the method, which are specifically described as follows:

First, a wet sulfide reaction is passivated on the cavity surface to produce a sulfide film after the vulcanization reaction, as a passivation layer, and then a CBD is used to prepare a ZnS film as a protective layer.

First, the solution preparation of the wet vulcanization passivation solution and the CBD preparation ZnS film will be described. Next, the steps of operating the bar resonator surface passivation and coating will be described.

1. The wet vulcanization process usually employs an aqueous solution of ammonium sulfide ((NH ₄ ) ₂ S) or an organic alcohol solution, an aqueous solution of sodium sulfide (Na ₂ S) or an organic alcohol solution.

2. The zinc ion in the solution of zinc sulfide (ZnS) film prepared by chemical bath deposition (CBD) is derived from zinc sulfate (ZnSO ₄ ) or zinc chloride (ZnCl ₂ ), etc., and the sulfur ion is derived from thiourea (SC (NH _{2 ) 2} ) or thioacetamide (CH ₃ CSNH ₂ ), etc., the complexing agent usually uses the following: ammonia water (NH ₃ · H ₂ O), ammonia water - hydrazine, sodium citrate (Na ₃ C ₆ H ₅ O ₇ ), ammonia triacetic acid (N(CH ₂ COOH) ₃ ), and the like. In addition, the additive hexamethylenetetramine can be added, which can maintain the pH of the mixed solution close to neutral, and at the same time, as a catalyst for the chemical reaction, the zinc sulfide film is continuous, the deposition rate is large, and the oxygen content is low.

Next, the present invention will be described by exemplifying a wet vulcanization passivation of a cavity surface to form a vulcanization reaction film, and then performing a chemical bath deposition method to deposit a zinc sulfide film on the vulcanized cavity surface.

Preparation of wet vulcanization passivation solution: 8-20% ammonium sulfide and t-butanol (tC ₄ H ₉ OH) were prepared into a passivation solution in a volume ratio of 1:1 and placed in a beaker. Heat in a water bath, the temperature is 40-60 ° C, keep the temperature constant, ready to use.

Solution preparation of zinc sulfide film by chemical bath deposition method: prepare three beakers, the first beaker contains 15 mL of 0.4 mol/L zinc sulfate solution, 15 mL of 0.4 mol/L ammonia triacetic acid solution, and 0.45 mL of concentrated sulfuric acid. 30 mL of deionized water. The second beaker contained 45 mol of 0.4 mol/L thioacetamide. The third beaker was filled with 1.0 mol/L of hexamethylenetetramine ((CH ₂ ) ₆ N ₄ ) 45 mL. The three beakers were stirred and heated in a water bath at 90 ° C for 8 min. Then, the solutions of the second and third beakers were simultaneously added to the first beaker and uniformly stirred, kept at a constant temperature, and prepared for use.

3. Specific process: First, the wafer of the laser device is cleaved into a bar; secondly, the laser bar to be passivated is immersed in the wet vulcanization passivation solution of the above step 1, the passivation time is 1- After 30 minutes of vulcanization passivation, the solution of the zinc sulfide film is prepared by immersing the bar in the chemical bath deposition method of the above step 2 (or the wet vulcanization passivation solution on the strip is first dried with nitrogen) for 10-30 min. . The strips are then removed from the solution and the zinc sulfide film can be as thick as 5 to 90 nm.

Subsequent bars can be used to deposit an optical film of the desired reflectivity on the front and rear cavity faces, or to further cut the bars into a single chip or array, depending on the application.

In the embodiment of the present application, after forming a passivation layer on the resonant cavity surface of the semiconductor laser device, the passivation layer is covered with a protective layer. The material of the protective layer is a wide band gap semiconductor material, which can prevent the cavity surface. Failure of passivation caused by oxidation or volatilization of the passivation layer. The function of the cavity surface passivation film of the semiconductor laser device of the present application mainly includes two aspects, namely, a passivation effect and stability thereof. Selecting a wide bandgap semiconductor material as a protective layer material can prevent the absorption of laser photons by the protective layer material, prevent oxidation or volatilization of the passivation layer material, and prevent the passivation layer material from failing. In this way, the cavity surface can be made blunt The film is effective for a long time, thereby ensuring the reliability of the semiconductor laser device and prolonging the service life of the semiconductor laser device.

The above description is only the embodiment of the present application, and thus does not limit the scope of the patent application, and the equivalent structure or equivalent process transformation of the specification and the drawings of the present application, or directly or indirectly applied to other related technologies. The fields are all included in the scope of patent protection of this application.

Claims (15)

1. A cavity surface passivation film for a semiconductor laser device, characterized in that the cavity surface passivation film comprises:

   a passivation layer covering the resonant cavity surface of the semiconductor laser device;

   And a protective layer covering the passivation layer, wherein the protective layer is formed by a chemical bath deposition method, and the protective layer is made of a wide band gap semiconductor material.
2. The cavity surface passivation film according to claim 1, wherein

   The chemical solution used in the chemical bath deposition method contains thiosulfate ions as a source of sulfur of a wide band gap sulfide; the chemical solution further comprises: zinc, cadmium, copper, magnesium, calcium, barium, strontium, boron, At least one of an ion of lithium, gallium, indium or tin or a complex ion.
3. The cavity surface passivation film according to claim 1, wherein

   The passivation layer is a sulfide film formed by reacting a cavity surface epitaxial material of the semiconductor laser device with a sulfur-containing compound; the passivation layer has a thickness of several to several tens of atomic layer thickness.
4. The cavity surface passivation film according to claim 1, wherein

   The material of the protective layer is a wide band gap sulfide semiconductor material; the protective layer has a thickness of 1-800 nm; and the protective layer is a component or all of the subsequent cavity surface optical film.
5. The cavity surface passivation film according to claim 4, wherein

   The wide band gap means that the band gap energy of the sulfide is greater than the photon energy of the laser.
6. The cavity surface passivation film according to claim 4, wherein

   The wide band gap sulfide semiconductor material includes: Zn(S _1-δ O _δ ), Cd(S _1-δ O _δ ), Cu(S _1-δ O _δ ), Cu ₂ (S _1-δ O _δ ) , Mg(S _1-δ O _δ ), Ca(S _1-δ O _δ ), Sr(S _1-δ O _δ ), Ba(S _1-δ O _δ ), B ₂ (S _1-δ O _{δ 3} , Al ₂ (S _1-δ O _δ ) ₃ , Ga ₂ (S _1-δ O _δ ) ₃ , In ₂ (S _1-δ O _δ ) ₃ , Sn(S _1-δ O _δ ) ₂ At least one of; wherein the range of δ is: 0.2 ≥ δ ≥ 0
7. The cavity surface passivation film according to claim 4, wherein

   The material of the protective layer is a mixture of wide band gap sulfide semiconductor materials.
8. The cavity surface passivation film according to claim 7, wherein

   The mixture of the wide band gap sulfide semiconductor material comprises: a mixture of Zn(S _1-δ O _δ ) and Cd(S _1-ξ O _ξ ), Cu(S _1-δ O _δ ) and Cu ₂ (S _1- a mixture of _ξ O _ξ ), a mixture of Zn(S _1-δ O _δ ) and Mg(S _1-δ O _δ ), 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 Al ₂ (S _1-δ O _δ ) ₃ and Ga ₂ (S _1-ξ O _ξ ) ₃ , Al At least one of a mixture of ₂ (S _1-δ O _δ ) ₃ and Mg(S _1-ξ O _ξ ), a mixture of Cu ₂ (S _1-δ O _δ ) and Sn(S _1-ξ O _ξ ) ₂ , wherein the ranges of δ and ξ are: 0.2 ≥ δ, ξ ≥ 0.
9. The cavity surface passivation film according to claim 4, wherein

   The material of the protective layer is an alloy semiconductor material of a wide band gap sulfide.
10. The cavity surface passivation film according to claim 9, wherein

    The alloy semiconductor material of the wide band gap sulfide includes: (Zn _1-x Cd _x )(S _1-δ O _δ ), (Zn _1-xy Cd _x Cu _y )(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-xy Ca _x Ba _y )(S _1-δ O _δ ), (Al _1-x Ga _x ) ₂ (S _1-δ O _δ ) ₃ , (Sn _1-x Cu _x )(S _1-δ At least one of O _δ ) ₂ , Cu ₄ Sn(S _1-δ O _δ ) ₄ , wherein the range of x and y is: 1 ≥ x, y ≥ 0, and the range of δ is: 0.2 ≥ δ ≥ 0.
11. A semiconductor laser device comprising a cavity surface passivation film, the cavity face passivation film being the cavity face passivation film according to any one of claims 1 to 10. .
12. A method for fabricating a resonant cavity surface passivation film of a semiconductor laser device, characterized in that the method comprises:

    Coating a film of a passivation layer on a cavity surface of the semiconductor laser device;

    The passivation layer is covered with a film of a protective layer by chemical bath deposition, and the material of the protective layer is a wide band gap semiconductor material.
13. The manufacturing method according to claim 12, wherein the film on the resonant cavity surface of the semiconductor laser device is covered with a passivation layer, comprising:

    Forming a passivation layer on the resonant cavity surface of the semiconductor laser device by a wet vulcanization method; the wet vulcanization method uses a sulfur-containing chemical solution containing: ammonium sulfide, lithium sulfide, and sulfurization a sulfide of at least one of sodium, potassium sulfide, magnesium sulfide, calcium sulfide, barium sulfide, barium sulfide, thiourea or thioacetamide; the solvent of the sulfur-containing chemical solution is water or an organic solvent, or a mixed solution of water and an organic solvent; after the wet vulcanization, the passivation layer has a thickness of several atomic layers to several tens of atomic layers.
14. The method according to claim 12, wherein the material of the protective layer is a wide band gap sulfide semiconductor material; and the band gap energy of the wide band gap sulfide semiconductor material is greater than the laser photon energy.
15. The method according to claim 12, wherein the chemical solution used in the chemical bath deposition method contains thiosulfate ions as a source of sulfur of the wide band gap sulfide; the chemical solution further comprises: zinc, At least one of ions or complex ions of cadmium, copper, magnesium, calcium, strontium, barium, boron, aluminum, gallium, indium or tin.

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