A semiconductor laser and a method for fabricating a semiconductor laser.

Abstract

The present invention provides a semiconductor laser and a method for preparing the semiconductor laser, wherein the semiconductor laser comprises an epitaxial wafer, a ridge waveguide formed on the epitaxial wafer, and a ridge waveguide anti-crushing structure arranged on both sides of the ridge waveguide, wherein the height of the ridge waveguide anti-crushing structure is higher than the height of the ridge waveguide, and the height difference between the ridge waveguide anti-crushing structure and the ridge waveguide is not less than a preset value, so that a clamp does not directly contact the ridge waveguide when clamping the semiconductor laser, thereby ensuring that the ridge waveguide is prevented from being crushed by the clamp.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor manufacturing, and in particular to a semiconductor laser and a method for preparing the semiconductor laser. Background Art

[0002] A semiconductor laser is a light source device made of semiconductor materials (usually gallium nitride, indium phosphide or gallium arsenide, etc.). It emits photons through the recombination of electrons and holes to form a beam of laser with a specific wavelength and coherence quality. Semiconductor lasers are widely used in various fields such as communications, medical treatment, measurement and manufacturing, and are favored for their miniaturization, high efficiency and reliability. Inside a semiconductor laser, the ridge waveguide is the core optical structure, which is usually the emission area of ​​the laser, has a relatively narrow width and a high refractive index, and can effectively limit and guide the laser beam. The ridge waveguide plays a vital role in the laser and directly affects the output power and beam quality of the laser.

[0003] However, if Figure 1 As shown in the figure, during the manufacturing process of semiconductor lasers, the ridge waveguide is usually at the same plane height as the supporting structures on both sides. Therefore, when the fixture is clamping the semiconductor laser, if the pressure distribution is uneven or the surface hardness of the fixture is high, it is easy to cause direct damage to the ridge waveguide or form indentations, and these damages may affect the optical performance of the ridge waveguide, and then affect the working efficiency and stability of the entire laser. Therefore, it is necessary to protect the ridge waveguide from pressure damage to avoid damage to the ridge waveguide by the fixture. Summary of the invention

[0004] The present invention provides a ridge waveguide preparation method and a ridge waveguide structure for preventing the ridge waveguide from being crushed, so as to solve the defect that the ridge waveguide is easily crushed in the prior art.

[0005] The present invention provides a semiconductor laser, comprising:

[0006] Epitaxial wafer;

[0007] A ridge waveguide formed on the epitaxial wafer;

[0008] The ridge waveguide anti-crushing structure is arranged on both sides of the ridge waveguide, and the height difference between the ridge waveguide anti-crushing structure and the ridge waveguide is not less than a preset value.

[0009] According to a semiconductor laser provided by the present invention, the preset value is 500 nm.

[0010] According to a semiconductor laser provided by the present invention, the semiconductor laser further comprises: a groove; the groove is formed in the epitaxial wafer and arranged on both sides of the ridge waveguide;

[0011] The spacing distance between the ridge waveguide anti-crushing structure and the outer side of the groove is 10-20um.

[0012] According to a semiconductor laser provided by the present invention, the epitaxial wafer includes: a substrate, a buffer layer, an N-type confinement layer, an N-type waveguide layer, an active region, a P-type waveguide layer, a P-type confinement layer and a contact layer.

[0013] According to a semiconductor laser provided by the present invention, the ridge waveguide anti-crushing structure and the epitaxial wafer are integrated into one structure.

[0014] The present invention also provides a method for preparing a semiconductor laser, for preparing any of the semiconductor lasers described above, the method comprising:

[0015] Providing an epitaxial wafer;

[0016] etching the epitaxial wafer to form a ridge waveguide;

[0017] A ridge waveguide anti-crushing structure is formed on both sides of the ridge waveguide, and a height difference between the ridge waveguide anti-crushing structure and the ridge waveguide is not less than a preset value.

[0018] According to a method for preparing a semiconductor laser provided by the present invention, after etching the epitaxial wafer to form a ridge waveguide, the method further comprises:

[0019] After depositing a dielectric film on the surface of the epitaxial wafer forming the ridge waveguide, an electric injection window is prepared;

[0020] The surface of the epitaxial wafer with the electric injection window prepared is subjected to metal evaporation and metal electroplating to form a P-surface electrode.

[0021] According to a method for preparing a semiconductor laser provided by the present invention, after forming a ridge waveguide anti-crushing structure on both sides of the ridge waveguide, the method further comprises:

[0022] The back side of the substrate of the epitaxial wafer with the P-side electrode is thinned and metal is evaporated to form an N-side electrode.

[0023] The present invention also provides a method for preparing a semiconductor laser, for preparing any of the semiconductor lasers described above, the method comprising:

[0024] Providing an epitaxial wafer;

[0025] Etching the epitaxial wafer based on a preset depth and a preset width to form a ridge waveguide anti-scratch structure and an etching area;

[0026] The etched area is corroded to form a ridge waveguide, the ridge waveguide anti-crushing structure is arranged on both sides of the ridge waveguide, and the height difference between the ridge waveguide anti-crushing structure and the ridge waveguide is not less than a preset value.

[0027] According to a method for preparing a semiconductor laser provided by the present invention, after the etched area is corroded to form a ridge waveguide, the method further comprises:

[0028] After depositing a dielectric film on the surface of the epitaxial wafer forming the ridge waveguide, an electric injection window is prepared;

[0029] Performing metal evaporation and metal electroplating on the surface of the epitaxial wafer on which the electric injection window is prepared to form a P-surface electrode;

[0030] The back side of the substrate of the epitaxial wafer with the P-side electrode is thinned and metal is evaporated to form an N-side electrode.

[0031] According to a method for preparing a semiconductor laser provided by the present invention, the method further comprises:

[0032] Obtaining a metal layer pre-evaporated on the ridge waveguide;

[0033] The preset value is determined based on the material of the metal layer and the clamping force of a clamp for pre-clamping the semiconductor laser.

[0034] According to a method for preparing a semiconductor laser provided by the present invention, the method further comprises:

[0035] The height difference between the ridge waveguide and the ridge waveguide anti-crushing structure is preset as an initial value, and the number of the initial values ​​is at least two;

[0036] Prepare a plurality of semiconductor laser samples based on any of the initial values, perform a trial clamping on each of the semiconductor laser samples, and determine scratch state information on the surface of the ridge waveguide of each of the semiconductor laser samples after the trial clamping;

[0037] Based on the scratch state information, at least one of the initial values ​​is determined to be the preset value.

[0038] According to a semiconductor laser manufacturing method provided by the present invention, based on the scratch state information, determining at least one of the initial values ​​as the preset value comprises:

[0039] Based on the scratch state information, determining the scratch size and scratch features on the surface of the ridge waveguide of the semiconductor laser sample, wherein the scratch features are used to characterize the exposed state of the ridge waveguide;

[0040] Obtaining the semiconductor laser sample in which the scratch size is not greater than a preset size threshold and the scratch feature is that the ridge waveguide is not exposed;

[0041] An initial value corresponding to the semiconductor laser sample is determined to be the preset value.

[0042] The present invention provides a semiconductor laser and a method for preparing a semiconductor laser, wherein the semiconductor laser includes an epitaxial wafer, a ridge waveguide formed on the epitaxial wafer, and a ridge waveguide anti-crushing structure arranged on both sides of the ridge waveguide, and the height of the ridge waveguide anti-crushing structure is higher than the height of the ridge waveguide, so that the clamp does not directly contact the ridge waveguide when clamping the semiconductor laser, thereby ensuring that the ridge waveguide is prevented from being crushed by the clamp. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0044] Figure 1 It is a structural schematic diagram of a ridge waveguide structure of a semiconductor laser provided by the prior art;

[0045] Figure 2 This is one of the structural schematic diagrams of the semiconductor laser provided by the present invention;

[0046] Figure 3 It is a schematic diagram of the structure of the epitaxial wafer provided by the present invention;

[0047] Figure 4 This is the second structural schematic diagram of the semiconductor laser provided by the present invention;

[0048] Figure 5 This is one of the flow diagrams of the method for preparing a semiconductor laser provided by the present invention;

[0049] Figure 6 This is the second schematic flow chart of the semiconductor laser preparation method provided by the present invention. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] Figure 2 is one of the structural schematic diagrams of the semiconductor laser provided by the present invention, such as Figure 2 As shown, the semiconductor laser includes:

[0052] Epitaxial wafer 210;

[0053] A ridge waveguide 220 formed on the epitaxial wafer 210;

[0054] The ridge waveguide anti-crushing structure 230 is disposed on both sides of the ridge waveguide 220 , and the height of the ridge waveguide anti-crushing structure 230 is higher than the height of the ridge waveguide 220 .

[0055] Here, since the height of the ridge waveguide anti-crushing structure 230 arranged on both sides of the ridge waveguide 220 is higher than the height of the ridge waveguide 220, the clamp can reduce or even eliminate the direct pressure applied by the clamp to the ridge waveguide area when clamping the semiconductor laser, thereby preventing the ridge waveguide from being clamped by the clamp.

[0056] Wherein, the height difference between the ridge waveguide anti-crushing structure and the ridge waveguide is not less than a preset value. In some embodiments, the preset value may be 500 nm.

[0057] In some embodiments, the semiconductor laser further includes: grooves formed in the epitaxial wafer and disposed on both sides of the ridge waveguide; the spacing distance between the ridge waveguide anti-crushing structure and the outer side of the groove is 10-20 um.

[0058] In some embodiments, Figure 3 As shown, the epitaxial wafer includes: a substrate, a buffer layer, an N-type confinement layer, an N-type waveguide layer, an active region, a P-type waveguide layer, a P-type confinement layer and a contact layer. The ridge waveguide is formed in the P-type confinement layer and the contact layer.

[0059] In some embodiments, Figure 4 As shown on the left, the ridge waveguide anti-crush structure and the epitaxial wafer may be separate structures. Figure 4 As shown on the right side, the ridge waveguide anti-crush structure and the epitaxial wafer can be integrated into an integrated structure, thereby avoiding the introduction of additional process steps when preparing the corresponding semiconductor laser.

[0060] A semiconductor laser provided by an embodiment of the present invention comprises an epitaxial wafer, a ridge waveguide formed on the epitaxial wafer, and a ridge waveguide anti-crushing structure arranged on both sides of the ridge waveguide, wherein the height of the ridge waveguide anti-crushing structure is higher than the height of the ridge waveguide, so that a clamp does not directly contact the ridge waveguide when clamping the semiconductor laser, thereby ensuring that the ridge waveguide is prevented from being crushed by the clamp.

[0061] Figure 5 is one of the flow diagrams of the method for preparing a semiconductor laser provided by the present invention, which is used to prepare a semiconductor laser provided by any of the above embodiments, such as Figure 5 As shown, the method includes:

[0062] Step 510, providing an epitaxial wafer;

[0063] Step 520, etching the epitaxial wafer to form a ridge waveguide;

[0064] Step 530: forming a ridge waveguide anti-crushing structure on both sides of the ridge waveguide, wherein the height difference between the ridge waveguide anti-crushing structure and the ridge waveguide is not less than a preset value.

[0065] Specifically, the epitaxial wafer includes: a substrate, a buffer layer, an N-type confinement layer, an N-type waveguide layer, an active region, a P-type waveguide layer, a P-type confinement layer and a contact layer. A ridge waveguide can be formed by etching the epitaxial wafer. Among them, the P-type confinement layer and the contact layer of the epitaxial wafer can be corroded to form a ridge waveguide. Subsequently, a ridge waveguide anti-crushing structure with a height higher than the ridge waveguide is formed on both sides of the ridge waveguide. In some embodiments, a ridge waveguide anti-crushing structure with a height higher than the ridge waveguide can be formed on the contact layer, thereby reducing or eliminating the direct pressure applied by the clamp on the ridge waveguide surface when clamping the semiconductor laser. Among them, the height difference between the ridge waveguide anti-crushing structure and the ridge waveguide is not less than a preset value.

[0066] In some embodiments, after etching the epitaxial wafer to form a ridge waveguide, a dielectric film may be deposited on the surface of the epitaxial wafer forming the ridge waveguide to prepare an electric injection window, and metal evaporation and metal electroplating may be performed on the surface of the epitaxial wafer on which the electric injection window is prepared to form a P-side electrode. Subsequently, the back side of the substrate of the epitaxial wafer on which the P-side electrode is prepared may be thinned and metal evaporated to form an N-side electrode.

[0067] Figure 6 FIG. 2 is a flow chart of a method for preparing a semiconductor laser provided by the present invention, which is used to prepare a semiconductor laser provided by any of the above embodiments, such as Figure 6 As shown, the method includes:

[0068] Step 610, providing an epitaxial wafer;

[0069] Step 620, etching the epitaxial wafer based on a preset depth and a preset width to form a ridge waveguide anti-scratch structure and an etching area;

[0070] Step 630, corroding the etched area to form a ridge waveguide, wherein the ridge waveguide anti-crushing structure is disposed on both sides of the ridge waveguide, and the height difference between the ridge waveguide anti-crushing structure and the ridge waveguide is not less than a preset value.

[0071] Specifically, in order to prevent the ridge waveguide from being crushed by the clamp, the provided epitaxial wafer is corroded based on a preset depth and a preset width to form an etched area and a ridge waveguide anti-crush structure, and the etched area is corroded to form a ridge waveguide. In some embodiments, the contact layer can be corroded to form an etched area and a ridge waveguide anti-crush structure. The ridge waveguide anti-crush structure is arranged on both sides of the ridge waveguide, and the height difference between the ridge waveguide anti-crush structure and the ridge waveguide is not less than a preset value, so as to reduce or even eliminate the direct pressure applied by the clamp on the ridge waveguide surface when clamping the semiconductor laser. Compared to Figure 5 The preparation method exemplified in the example, in which the ridge waveguide anti-crush structure is formed by etching before the ridge waveguide, and the ridge waveguide anti-crush structure is located on both sides of the ridge waveguide and is integrated with the epitaxial wafer, forming a structure such as Figure 4 The semiconductor laser structure shown on the right.

[0072] In some embodiments, after the etched area is corroded to form a ridge waveguide, an electric injection window can be prepared by depositing a dielectric film on the surface of the epitaxial wafer forming the ridge waveguide, and then the surface of the epitaxial wafer with the electric injection window prepared is subjected to metal evaporation and metal electroplating to form a P-side electrode, and the back side of the substrate of the epitaxial wafer with the P-side electrode is thinned and metal evaporated to form an N-side electrode.

[0073] In some embodiments, the semiconductor laser manufacturing method further includes:

[0074] Obtaining a metal layer pre-evaporated on the ridge waveguide;

[0075] The preset value is determined based on the material of the metal layer and the clamping force of a clamp for pre-clamping the semiconductor laser.

[0076] Here, after obtaining the metal layer pre-evaporated on the ridge waveguide, the material of the metal layer can be determined, thereby determining the deformation parameters of the metal layer. Combined with the material of the metal layer and the clamping force of the clamp for pre-clamping the semiconductor laser, the degree of deformation of the metal layer caused by the clamp when clamping the semiconductor laser with the corresponding clamping force can be evaluated. According to the degree of deformation of the metal layer caused by the clamp when clamping the semiconductor laser with the corresponding clamping force, a suitable preset value can be set so that the height difference between the ridge waveguide and the ridge waveguide anti-crushing structure is sufficient to compensate for the deformation of the metal layer evaporated on the surface of the ridge waveguide when the clamp clamps the semiconductor laser with the corresponding clamping force, thereby avoiding damage to the ridge waveguide when the clamp clamps the semiconductor laser.

[0077] In some other embodiments, the semiconductor laser manufacturing method further includes:

[0078] The height difference between the ridge waveguide and the ridge waveguide anti-crushing structure is preset as an initial value, and the number of the initial values ​​is at least two;

[0079] Prepare a plurality of semiconductor laser samples based on any of the initial values, perform a trial clamping on each of the semiconductor laser samples, and determine scratch state information on the surface of the ridge waveguide of each of the semiconductor laser samples after the trial clamping;

[0080] Based on the scratch state information, at least one of the initial values ​​is determined to be the preset value.

[0081] Specifically, the height difference between the ridge waveguide and the ridge waveguide anti-crushing structure can be preset to a variety of initial values, such as 300nm, 500nm, 800nm, etc. For any initial value, a DOE (DESIGN OF EXPERIMENT) verification tool can be used to prepare several semiconductor laser samples corresponding to the corresponding initial value. The preparation method of the semiconductor laser sample here is the same as the preparation method given in the above embodiment, and will not be repeated here. Subsequently, each semiconductor laser sample is trial clamped to determine the scratch state information on the surface of the ridge waveguide of each semiconductor laser sample after the trial clamping. Among them, the scratch state information on the surface of the ridge waveguide of the semiconductor laser sample includes the scratch size and scratch characteristics, and the scratch characteristics are used to characterize the exposed state of the ridge waveguide in the corresponding scratch area.

[0082] Here, a clamp can be used to test clamp each semiconductor laser sample, and then a microscope image of the ridge waveguide surface of each semiconductor laser sample after the test clamp is collected. Based on the automatic clamp detection algorithm, the microscope image of the ridge waveguide surface of each semiconductor laser sample after the test clamp is clamped to detect the scratch area on the ridge waveguide surface of each semiconductor laser sample after the test clamp, and the scratch area on the ridge waveguide surface of each semiconductor laser sample after the test clamp is determined. Subsequently, based on the image features of the scratch area on the ridge waveguide surface of each semiconductor laser sample after the test clamp, the scratch size and scratch features on the ridge waveguide surface of each semiconductor laser sample after the test clamp are determined. Among them, regarding the scratch size, based on the pixel area of ​​the scratch area, the number of pixels in the corresponding direction can be determined from each direction to obtain the maximum scratch width in each direction, and the scratch size on the ridge waveguide surface can be determined based on the maximum value of the maximum scratch width in each direction. The scratch feature characterizes whether there is a problem of ridge waveguide exposure in the corresponding scratch area (that is, the contact layer or P-type confinement layer contained in the ridge waveguide leaks out). Considering that there is a difference in image brightness between the ridge waveguide and the metal layer evaporated on the surface of the ridge waveguide in the microscope image, it is possible to determine whether there is a problem of ridge waveguide exposure based on the uniformity of pixel brightness in the scratch area. For example, if the difference between the pixel brightness at adjacent positions in the scratch area is greater than a preset brightness threshold, it can be determined that there is a problem of ridge waveguide exposure.

[0083] Based on the scratch state information on the surface of the ridge waveguide of each semiconductor laser sample corresponding to each initial value, at least one initial value can be determined as the above-mentioned preset value. Among them, based on the scratch state information on the surface of the ridge waveguide of each semiconductor laser sample, the scratch size and scratch characteristics on the surface of the ridge waveguide of the corresponding semiconductor laser sample can be determined, and a semiconductor laser sample with a scratch size not greater than a preset size threshold and a scratch characteristic of the ridge waveguide not being exposed is obtained. Subsequently, the initial value corresponding to the semiconductor laser sample with a scratch size not greater than the preset size threshold and a scratch characteristic of the ridge waveguide not being exposed is determined to be the above-mentioned preset value.

[0084] In other embodiments, the minimum value of the initial value corresponding to the semiconductor laser sample with a scratch size not greater than a preset size threshold and a scratch feature of an unexposed ridge waveguide can be determined as the minimum protection thickness, and the epitaxial wafer sample is etched based on the minimum protection thickness to form an etched area, and the corrosion depth of each part in the etched area is determined, thereby determining the corrosion difference value of the etched area. Here, considering the uniformity of the P-type epitaxial wafer when wet etching is used, the epitaxial wafer can be etched according to the above minimum protection thickness to form an etched area, and then the actual corrosion depth corresponding to the position with the shallowest corrosion depth in the etched area and the average value of the actual corrosion depth of the entire etched area are determined, and the difference between the actual corrosion depth corresponding to the position with the shallowest corrosion depth and the average value of the actual corrosion depth of the entire etched area is determined as the above corrosion difference value. Subsequently, the sum of the minimum protection thickness and the corrosion difference value is determined as the above preset value.

[0085] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A semiconductor laser, characterized in that: The semiconductor laser comprises: Epitaxial wafer; A ridge waveguide formed on the epitaxial wafer; A ridge waveguide anti-crushing structure is arranged on both sides of the ridge waveguide, and the height difference between the ridge waveguide anti-crushing structure and the ridge waveguide is not less than a preset value; The ridge waveguide anti-crush structure is integrated with the epitaxial wafer, and the ridge waveguide anti-crush structure is formed on the contact layer of the epitaxial wafer; The preset value is determined based on any of the following methods: Obtaining a metal layer pre-evaporated on the ridge waveguide; determining the preset value based on the material of the metal layer and the clamping force of the clamp pre-clamping the semiconductor laser; Or, the height difference between the preset ridge waveguide and the ridge waveguide anti-crushing structure is an initial value, and the number of the initial values ​​is at least two; based on any of the initial values, a number of semiconductor laser samples are prepared, and a trial clamping is performed on each of the semiconductor laser samples to determine the scratch state information on the surface of the ridge waveguide of each of the semiconductor laser samples after the trial clamping; based on the scratch state information, at least one of the initial values ​​is determined to be the preset value.

2. The semiconductor laser according to claim 1, characterized in that The semiconductor laser further comprises: a groove; the groove is formed in the epitaxial wafer and arranged on both sides of the ridge waveguide; The spacing distance between the ridge waveguide anti-crushing structure and the outer side of the groove is 10-20um.

3. The semiconductor laser according to claim 2, characterized in that The preset value is 500 nm.

4. The semiconductor laser according to any one of claims 1 to 3, characterized in that: The epitaxial wafer comprises: a substrate, a buffer layer, an N-type limiting layer, an N-type waveguide layer, an active region, a P-type waveguide layer, a P-type limiting layer and a contact layer.

5. The semiconductor laser according to claim 1, characterized in that Based on the scratch state information, determining at least one of the initial values ​​as the preset value comprises: Based on the scratch state information, determining the scratch size and scratch features on the surface of the ridge waveguide of the semiconductor laser sample, wherein the scratch features are used to characterize the exposed state of the ridge waveguide; Obtaining the semiconductor laser sample in which the scratch size is not greater than a preset size threshold and the scratch feature is that the ridge waveguide is not exposed; An initial value corresponding to the semiconductor laser sample is determined to be the preset value.

6. A method for preparing a semiconductor laser, characterized in that: The method is used to prepare the semiconductor laser according to any one of claims 1 to 4, and the method comprises: Providing an epitaxial wafer; Etching the epitaxial wafer based on a preset depth and a preset width to form a ridge waveguide anti-scratch structure and an etching area; The etched area is corroded to form a ridge waveguide, the ridge waveguide anti-crushing structure is arranged on both sides of the ridge waveguide, and the height difference between the ridge waveguide anti-crushing structure and the ridge waveguide is not less than a preset value.

7. The laser preparation method according to claim 6, characterized in that: After the etched area is corroded to form a ridge waveguide, the method further comprises: After depositing a dielectric film on the surface of the epitaxial wafer forming the ridge waveguide, an electric injection window is prepared; Performing metal evaporation and metal electroplating on the surface of the epitaxial wafer on which the electric injection window is prepared to form a P-surface electrode; The back side of the substrate of the epitaxial wafer with the P-side electrode is thinned and metal is evaporated to form an N-side electrode.

Images