Semiconductor laser, preparation method thereof and laser projection equipment

Abstract

The embodiment of the invention provides a semiconductor laser, a preparation method thereof and laser projection equipment. The semiconductor laser comprises a substrate; the epitaxial layer is located on the first surface of the substrate; the epitaxial layer comprises a buffer layer, a first limiting layer, a first waveguide layer, an active layer, a second waveguide layer and a second limiting layer which are stacked in sequence; the epitaxial layer further comprises an insulating layer and an ohmic contact layer; the first electrode layer is located on the side, away from the substrate, of the epitaxial layer; the second electrode layer is located on the second surface of the substrate; and the at least one mode loss structure is located at a peak position of a high-order mode of the semiconductor laser, and the mode loss structure comprises a blind hole which extends from the second electrode layer to the interior of the second limiting layer along the thickness direction of the semiconductor laser. The embodiment of the invention is used for improving the quality of the output light beam of the wide-strip-shaped high-power semiconductor laser under the condition that the output power of the wide-strip-shaped high-power semiconductor laser is not reduced.

Description

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on March 15, 2024, with application number 2024103020053, the contents of which are incorporated by reference into this application. Technical Field

[0002] The embodiments of the present application relate to the field of laser projection technology, and more specifically, to a semiconductor laser and a method for manufacturing the same, and a laser projection device. Background Art

[0003] Due to its advantages such as wide output band coverage, high output power, small size and long life, broad area high-power semiconductor lasers (BA-HPLD) are widely used in military, civilian and other fields.

[0004] As the scope of application continues to expand, the output power and beam quality of wide-stripe high-power semiconductor lasers are facing higher standards. However, when a large current is injected into a wide-stripe high-power semiconductor laser to achieve high-power output, the heat generated inside it will cause the material temperature to rise, which in turn causes the refractive index to change, resulting in a thermal lens effect, thereby changing the optical path in the resonant cavity. This will change the intracavity conditions that are originally unfavorable for the propagation of high-order modes, and stimulate the generation of high-order modes. In addition, the dense carriers at the edge of the strip of the wide-stripe high-power semiconductor laser provide mode gain for the generation of high-order modes, further promoting the generation of high-order modes. As the injected current increases, these two factors will cause the far-field slow axis divergence angle to increase rapidly, reducing the quality of the output beam of the wide-stripe high-power semiconductor laser. Summary of the Invention

[0005] The exemplary embodiments of the present application provide a semiconductor laser, a method for manufacturing the same, and a laser projection device, which are used to improve the quality of the output beam of a wide-strip high-power semiconductor laser without reducing the output power of the wide-strip high-power semiconductor laser.

[0006] The technical solutions provided by the embodiments of this application are as follows:

[0007] In a first aspect, an embodiment of the present application provides a semiconductor laser, comprising:

[0008] substrate;

[0009] an epitaxial layer, the epitaxial layer being located on the first surface of the substrate; the epitaxial layer comprising a buffer layer, a first confinement layer, a first waveguide layer, an active layer, a second waveguide layer, and a second confinement layer stacked in sequence; the epitaxial layer further comprising: an insulating layer located on a side of the second confinement layer away from the substrate and covering a non-current injection region, and an ohmic contact layer located on a side of the second confinement layer away from the substrate and covering a current injection region;

[0010] a first electrode layer, the first electrode layer being located on a side of the epitaxial layer away from the substrate;

[0011] a second electrode layer, the second electrode layer being located on the second surface of the substrate;

[0012] At least one mode loss structure is located at a peak position of a high-order mode of the semiconductor laser, and the mode loss structure includes a blind hole extending from the second electrode layer along the thickness direction of the semiconductor laser to the inside of the second confinement layer.

[0013] In a second aspect, an embodiment of the present application provides a method for preparing a semiconductor laser, for preparing the semiconductor laser described in the first aspect, the method comprising:

[0014] forming the buffer layer, the first confinement layer, the first waveguide layer, the active layer, the second waveguide layer and the second confinement layer in sequence on the first surface of the substrate;

[0015] forming the ohmic contact layer in the current injection region of the second confinement layer;

[0016] forming the at least one mode loss structure at a peak position of a high-order mode of the semiconductor laser;

[0017] forming the insulating layer in a non-current injection region of the second confinement layer;

[0018] forming a first electrode layer covering the ohmic contact layer;

[0019] The second electrode layer is formed on the second surface of the substrate.

[0020] In a third aspect, an embodiment of the present application provides a laser projection device, comprising: a display control component, a light source driving component, a laser light source, a light valve, and a lens;

[0021] The display control component is connected to the light source driving component and the light valve respectively, and the light source driving component is connected to the laser light source;

[0022] The laser light source includes the semiconductor laser described in the first aspect or a semiconductor laser prepared by the method for preparing a semiconductor laser described in the second aspect.

[0023] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a computing device, the computing device implements the method for preparing a semiconductor laser provided in an embodiment of the present application.

[0024] In a fifth aspect, an embodiment of the present application provides a computer program product. When the computer program product is run on a computer, the computer implements the method for preparing a semiconductor laser provided in an embodiment of the present application.

[0025] A semiconductor laser provided in an embodiment of the present application includes: a substrate, an epitaxial layer, a first electrode layer, a second electrode layer, and at least one mode loss structure; wherein the epitaxial layer is located on the first surface of the substrate and includes a buffer layer, a first confinement layer, a first waveguide layer, an active layer, a second waveguide layer, and a second confinement layer stacked in sequence; the epitaxial layer further includes: an insulating layer located on a side of the second confinement layer away from the substrate and covering a non-current injection region, and an ohmic contact layer located on a side of the second confinement layer away from the substrate and covering a current injection region; the first electrode layer is located on a side of the epitaxial layer away from the substrate; the second electrode layer is located on the second surface of the substrate; the at least one mode loss structure is located at a peak position of a high-order mode of the semiconductor laser, and the mode loss structure includes a blind hole extending from the second electrode layer along the thickness direction of the semiconductor laser to the interior of the second confinement layer. Since the semiconductor laser provided in the embodiment of the present application includes at least one mode loss structure located at the peak position of the high-order mode of the semiconductor laser, the semiconductor laser provided in the above embodiment can increase the loss and lasing threshold of the high-order mode, weaken the mode competition between the fundamental mode and the high-order mode in the semiconductor laser resonant cavity, thereby reducing the lateral far-field divergence angle of the semiconductor laser and improving the beam quality of the semiconductor laser. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the implementation methods in the embodiments of the present application or related technologies, the following is a brief introduction to the drawings required for use in the embodiments or related technology descriptions. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0027] Figure 1 shows a schematic structural diagram of a semiconductor laser in some embodiments;

[0028] Figure 2 shows a cross-sectional view of a semiconductor laser in some embodiments;

[0029] Figure 3 A schematic diagram showing a mode loss structure in some embodiments;

[0030] Figure 4 shows a schematic structural diagram of a semiconductor laser in some other embodiments;

[0031] Figure 5 shows a near-field distribution diagram of a semiconductor laser in some embodiments;

[0032] Figure 6 shows the far-field distribution diagram of the semiconductor laser in some embodiments;

[0033] Figure 7 A top view of a first electrode layer of a semiconductor laser in some embodiments is shown;

[0034] Figure 8 A schematic diagram showing the location of mode loss structures in some embodiments;

[0035] Figure 9 A flowchart showing the steps of a method for preparing a semiconductor laser in some embodiments is shown;

[0036] Figure 10 Schematic diagram of a scene displayed by laser projection in some embodiments is shown;

[0037] Figure 11 shows a schematic structural diagram of a laser projection device in some embodiments;

[0038] Figure 12 Shows a schematic structural diagram of a laser projection device in some other embodiments;

[0039] Figure 13 shows a schematic structural diagram of a laser light source in some embodiments;

[0040] Figure 14 A cross-sectional view of a laser light source in some embodiments is shown. DETAILED DESCRIPTION

[0041] In order to make the purpose and implementation of this application clearer, the exemplary implementation of this application will be clearly and completely described below in conjunction with the drawings in the exemplary embodiments of this application. Obviously, the described exemplary embodiments are only part of the embodiments of this application, not all of the embodiments.

[0042] It should be noted that the brief descriptions of terms in this application are only for the purpose of facilitating the understanding of the embodiments described below, and are not intended to limit the embodiments of this application. Unless otherwise specified, these terms should be understood according to their ordinary and usual meanings.

[0043] The terms "comprise," "include," and "have," and any variations thereof, are intended to cover but not exclude inclusion; for example, a product or device comprising a list of components is not necessarily limited to all the components expressly listed but may include other components not expressly listed or inherent to such product or device.

[0044] In the description of the present invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer" and the like, indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0045] The embodiment of the present application provides a semiconductor laser, Figure 1 The schematic diagram of the semiconductor laser structure. Figure 2 is a cross-sectional view of the semiconductor laser, refer to Figure 1 and Figure 2 As shown, the semiconductor laser provided in the embodiment of the present application includes:

[0046] A substrate 10 , an epitaxial layer 20 , a first electrode layer 30 , a second electrode layer 40 and at least one mode loss structure 50 .

[0047] The epitaxial layer 20 is located on the first surface of the substrate 10. The epitaxial layer 20 includes a buffer layer 21, a first confinement layer 22, a first waveguide layer 23, an active layer 24, a second waveguide layer 25, and a second confinement layer 26, which are stacked in sequence. The epitaxial layer 20 also includes an insulating layer 27 located on a side of the second confinement layer 26 away from the substrate 10 and covering a non-current injection region, and an ohmic contact layer 28 located on a side of the second confinement layer 26 away from the substrate 10 and covering a current injection region.

[0048] The first electrode layer 30 is located on a side of the epitaxial layer 20 away from the substrate.

[0049] The second electrode layer 40 is located on the second surface of the substrate 10 .

[0050] The at least one mode loss structure is located at a peak position of a high-order mode of the semiconductor laser. The mode loss structure includes a blind hole extending from the second electrode layer 40 along the thickness direction of the semiconductor laser to the inside of the second confinement layer 26 .

[0051] In some embodiments, the substrate 10 is an N-type substrate formed of gallium arsenide (GaAs).

[0052] In some embodiments, the buffer layer 21 is made of the same material as the substrate 10. For example, if the substrate 10 is an N-type substrate formed of gallium arsenide (GaAs), the buffer layer 21 is formed of GaAs. For another example, if the substrate 10 is an N-type substrate formed of gallium nitride (GaN), the buffer layer 21 is formed of GaN.

[0053] In some embodiments, the first restriction layer 22 is composed of AI x1 In 1-x1 P is formed, where 0.48≤x1≤0.52.

[0054] In some embodiments, the first waveguide layer 23 is composed of (AI x2 Ga 1-x2 ) y1 In 1-y1 P is formed, where 0.4≤x2≤0.9, 0.4≤y1≤0.6.

[0055] In some embodiments, the active layer 24 includes: a first barrier layer, at least one quantum well layer, and a second barrier layer stacked in sequence.

[0056] In some embodiments, the quantum well layer is made of Ga x3 In 1-x3 P is formed, 0.35≤X3≤0.55. The number of quantum well layers included in the active layer 24 is greater than or equal to 1 and less than or equal to 3. The thickness of the quantum well layer is 7-13 nm.

[0057] In some embodiments, the first barrier layer and the second barrier layer are composed of (AI x4 Ga 1-x4 ) y2 In 1-y2 P is formed, 0.3≤x4≤0.62, 0.4≤y2≤0.6. The thickness of the first barrier layer and the second barrier layer is greater than or equal to 5 nanometers (nm) and less than or equal to 15 nanometers. In addition, the thickness of the first barrier layer and the second barrier layer can be the same or different. For example, the thickness of the first barrier layer can be greater than the thickness of the second barrier layer. This embodiment of the present application is not limited to this.

[0058] In some embodiments, the second waveguide layer 25 is composed of (AI x5 Ga 1-x5 ) y3 In 1-y3 P is formed, 0.4≤x5≤0.9, 0.4≤y3≤0.6.

[0059] In some embodiments, the second restriction layer 26 is composed of AI x6 In 1-x6 P formation, 0.48≤x6≤0.52.

[0060] In some embodiments, the insulating layer 27 is formed of silicon dioxide (SiO 2 ) and has a thickness of 150 to 350 microns. For example, the thickness of the insulating layer 27 may be 200 microns.

[0061] In some embodiments, the ohmic contact layer 28 is formed of highly doped GaAs.

[0062] In some embodiments, the first confinement layer is an N-type confinement layer, and the first waveguide layer is an N-type waveguide layer; the second confinement layer is a P-type confinement layer, and the second waveguide layer is a P-type waveguide layer.

[0063] Since the non-current injection region of the epitaxial layer 20 is covered with the insulating layer 27, when current is injected into the semiconductor laser through the first electrode layer 30, the current will only enter the semiconductor laser through the ohmic contact layer 28 in the current injection region, and will not enter the semiconductor laser through the non-current injection region.

[0064] In some embodiments, the peak position of the high-order mode portion of the semiconductor laser coincides with the peak position of the fundamental mode of the semiconductor laser. For the high-order mode peak position that coincides with the peak position of the fundamental mode of the semiconductor laser, the embodiment of the present application may not set a mode loss structure, thereby avoiding affecting the output power of the semiconductor laser and / or the quality of the output beam.

[0065] A semiconductor laser provided in an embodiment of the present application includes: a substrate, an epitaxial layer, a first electrode layer, a second electrode layer, and at least one mode loss structure; wherein the epitaxial layer is located on the first surface of the substrate and includes a buffer layer, a first confinement layer, a first waveguide layer, an active layer, a second waveguide layer, and a second confinement layer stacked in sequence; the epitaxial layer further includes: an insulating layer located on a side of the second confinement layer away from the substrate and covering a non-current injection region, and an ohmic contact layer located on a side of the second confinement layer away from the substrate and covering a current injection region; the first electrode layer is located on a side of the epitaxial layer away from the substrate; the second electrode layer is located on the second surface of the substrate; the at least one mode loss structure is located at a peak position of a high-order mode of the semiconductor laser, and the mode loss structure includes a blind hole extending from the second electrode layer along the thickness direction of the semiconductor laser to the interior of the second confinement layer. Since the semiconductor laser provided in the embodiment of the present application includes at least one mode loss structure located at the peak position of the high-order mode of the semiconductor laser, the semiconductor laser provided in the above embodiment can increase the loss and lasing threshold of the high-order mode, weaken the mode competition between the fundamental mode and the high-order mode in the semiconductor laser resonant cavity, thereby reducing the lateral far-field divergence angle of the semiconductor laser and improving the beam quality of the semiconductor laser.

[0066] It should be noted that the mode loss structure of the semiconductor laser can also serve as a scattering center for carriers, regulating and redistributing the carriers at the edge of the semiconductor laser, thereby increasing carrier recombination and improving the output power and conversion efficiency of the semiconductor laser.

[0067] In some embodiments, reference Figure 3 As shown, the distance L from the bottom of the blind hole to the first surface of the second restriction layer 26 is 20-50 nanometers. The first surface of the second restriction layer 26 is the surface of the second restriction layer 26 close to the substrate 10.

[0068] That is, the etching depth of the blind hole slightly contacts the bottom of the second confinement layer 26 , and the remaining thickness of the second confinement layer 26 is 20-50 nanometers.

[0069] Setting the distance L from the bottom of the blind hole to the first surface of the second confinement layer 26 to 20 to 50 nanometers is beneficial to moderate overlap between the mode loss structure and the light field mode, thereby avoiding significant optical loss and maintaining the output power and efficiency of the laser.

[0070] In some embodiments, reference Figure 3 As shown, the aperture d of the blind hole is 3 to 7 microns.

[0071] If the aperture of the blind hole is small, it will cause greater difficulty in the preparation of the semiconductor laser, which will bring inconvenience to the production and preparation; if the aperture of the blind hole is large, it will cause loss of the fundamental mode, reducing the output power and conversion efficiency of the semiconductor laser and other performance. Therefore, the embodiment of the present application comprehensively considers the preparation difficulty and the impact on the performance of the semiconductor laser, and sets the aperture of the blind hole to 3 to 7 microns.

[0072] In some embodiments, the number of mode loss structures at the peak position of the high-order mode of the semiconductor laser is positively correlated with the offset distance of the peak position of the high-order mode of the semiconductor laser, wherein the offset distance of the peak position of the high-order mode of the semiconductor laser is the distance from the peak position of the high-order mode of the semiconductor laser to the peak position of the fundamental mode of the semiconductor laser.

[0073] Since the peak position of the fundamental mode of the semiconductor laser is the axis of the conductive region, the number of the mode loss structures at the peak position of the high-order mode of the semiconductor laser is positively correlated with the offset distance of the peak position of the high-order mode of the semiconductor laser, that is, the number of the mode loss structures increases from the axis of the conductive region to both sides.

[0074] Since the fundamental mode energy is mainly concentrated at the axis position of the conductive region, and the above embodiment sets the number of mode loss structures to increase from the axis of the conductive region to both sides, the above embodiment can increase the loss of high-order modes while reducing the impact on the fundamental mode of the semiconductor laser.

[0075] In some embodiments, the substrate, the buffer layer, and the first confinement layer are formed of N-type doped materials; the second confinement layer and the ohmic contact layer are formed of P-type doped materials; and the first electrode layer, the second electrode layer, the first waveguide layer, the second waveguide layer, and the active layer are formed of undoped materials.

[0076] Reference Figure 4 As shown, in some embodiments, the thickness of the second confinement layer 26 of the epitaxial layer 20 of the semiconductor laser provided in the above embodiments is greater in the current injection region than in the non-current injection region, thereby forming a strip-shaped ridge structure in the current injection region, and the first electrode layer 30 only covers the strip-shaped ridge structure.

[0077] Figure 4 In the semiconductor laser shown, the first electrode layer 30 only covers the strip-shaped ridge structure. When current is injected into the semiconductor laser through the first electrode layer 30, the current only enters the semiconductor laser through the ohmic contact layer 28 in the current injection area, and does not enter the semiconductor laser through the non-current injection area. Figure 4 The semiconductor laser shown is Figure 1The current injection methods of the semiconductor lasers shown are the same.

[0078] The semiconductor lasers provided by the embodiments of the present application are illustrated by the following examples.

[0079] Refer to Figure 5 and Figure 6 as shown, Figure 5 which are the lateral near-field distribution diagrams of different modes of a wide-strip high-power semiconductor laser with a stripe width of 85 microns, Figure 6 and the horizontal far-field distribution diagrams of different modes of a wide-strip high-power semiconductor laser with a stripe width of 85 microns. As Figure 5 shown, a wide-strip high-power semiconductor laser with a stripe width of 85 microns has 5 modes, namely the fundamental mode (1st), the second-order mode (2nd), the third-order mode (3rd), the fourth-order mode (4th), and the fifth-order mode (5th), and as Figure 6 shown, the existence of the second-order mode (2nd), the third-order mode (3rd), the fourth-order mode (4th), and the fifth-order mode (5th) makes the corresponding far-field divergence angle wider, seriously affecting the output beam quality of the laser.

[0080] Refer to Figure 7 as shown, Figure 7 which is a top view of the first electrode layer 30 of a wide-strip high-power semiconductor laser with a width of 85 microns. Among them, the position shown by the straight line 71 on the first electrode layer 30 is the peak position of the fundamental mode (1st) of the semiconductor laser, and the positions shown by the straight lines 72 to 79 are the peak positions of the second-order mode (2nd), the third-order mode (3rd), the fourth-order mode (4th), and the fifth-order mode (5th) of the semiconductor laser. Therefore, refer to Figure 8 as shown, the mode loss structures described in the above embodiments can be set at the positions shown by the straight lines 72 to 79 to increase the loss of high-order modes and the lasing threshold. Define the distance from the positions shown by the straight lines 72 to 79 to the peak position of the fundamental mode of the semiconductor laser (the position shown by the straight line 71) as D72 to D79, then: D75 = D76 < D74 = D77 < D73 = D78 < D72 = D79. Therefore, the number of mode loss structures at the positions shown by the straight lines 75 and 76 can be made less than the number of mode loss structures at the positions shown by the straight lines 74 and 77, the number of mode loss structures at the positions shown by the straight lines 74 and 77 is less than the number of mode loss structures at the positions shown by the straight lines 73 and 78, and the number of mode loss structures at the positions shown by the straight lines 73 and 78 is less than the number of mode loss structures at the positions shown by the straight lines 72 and 79. Exemplarily, refer to Figure 8As shown, the number of mode loss structures 50 at the positions indicated by straight line 75 and straight line 76 is 3, the number of mode loss structures 50 at the positions indicated by straight line 74 and straight line 77 is 4, the number of mode loss structures 50 at the positions indicated by straight line 73 and straight line 78 is 5, and the number of mode loss structures 50 at the positions indicated by straight line 72 and straight line 79 is 6.

[0081] The present application also provides a method for preparing the semiconductor laser provided in the above embodiment, referring to Figure 9 As shown, the method for preparing the semiconductor laser includes the following steps:

[0082] S901 , sequentially forming the buffer layer, the first confinement layer, the first waveguide layer, the active layer, the second waveguide layer, and the second confinement layer on the first surface of the substrate.

[0083] In some embodiments, the buffer layer, the first confinement layer, the first waveguide layer, the active layer, the second waveguide layer, the second confinement layer, and the ohmic contact layer are sequentially formed on the first surface of the substrate, including: placing the substrate in an organic metal chemical vapor deposition (MOCVD) device for surface heat treatment, sequentially using GaAs to grow a buffer layer, using Al x1 In 1-x1 P grows the first confinement layer, through (AI x2 Ga 1-x2 ) y1 In 1-y1 The first waveguide layer is grown by P, and Ga x3 In 1-x3 P and (AI x4 Ga 1-x4 ) y2 In 1-y2 P grows the active layer, through (AI x5 Ga 1-x5 ) y3 In 1-y3 P grows the second waveguide layer through AI x6 In 1-x6 A second confinement layer is grown using P, wherein 0.48≤x1≤0.52, 0.4≤x2≤0.9, 0.4≤y1≤0.6, 0.35≤x3≤0.55, 0.3≤x4≤0.62, 0.4≤y2≤0.6, 0.4≤x5≤0.9, 0.4≤y3≤0.6, and 0.48≤x6≤0.52.

[0084] S902 , forming the ohmic contact layer in the current injection region of the second confinement layer.

[0085] In some embodiments, the ohmic contact layer is formed in the current injection region of the second confinement layer, including: first, growing a GaAs layer on the second confinement layer by MOCVD equipment to complete the growth of the epitaxial material, then forming a mask on the surface of the GaAs layer by a photolithography device, and performing photolithography and etching using a photolithography machine and dry and / or wet etching equipment to remove the GaAs layer in the non-current injection region and retain the GaAs layer in the current injection region to form the ohmic contact layer in the current injection region of the second confinement layer.

[0086] In some embodiments, after removing the ohmic contact layer in the non-current injection region, the second confinement layer may be further etched to a preset thickness, so that the thickness of the second confinement layer in the current injection region is greater than that in the non-current injection region.

[0087] S903 , forming the at least one mode loss structure at a peak position of a high-order mode of the semiconductor laser.

[0088] In some embodiments, forming the at least one mode loss structure at the peak position of the high-order mode of the semiconductor laser includes: forming the at least one mode loss structure at the peak position of the high-order mode of the semiconductor laser by dry etching using a photoresist as a mask. Specifically, a photoresist mask for the mode loss structure is first formed on the ohmic contact layer using a photoresist coating device, and then etching is performed using a dry etching device until the photoresist is etched into the second confinement layer, thereby forming the at least one mode loss structure at the peak position of the high-order mode of the semiconductor laser.

[0089] In some embodiments, when forming the at least one mode loss structure at the peak position of the high-order mode of the semiconductor laser, etching is performed until 20 to 50 nanometers remain in the second confinement layer.

[0090] S904 , forming the insulating layer in the non-current injection region of the second confinement layer.

[0091] In some embodiments, the insulating layer is formed in the non-current injection area of ​​the second confinement layer, including: using plasma enhanced chemical vapor deposition (PECVD) or magnetron sputtering equipment to form a SiO2 layer on the surface of the second confinement layer, with a deposition thickness of 150 to 350 microns, and then using a photolithography device with a photoresist as a mask to form a mask in the non-current injection area, and using reactive ion etching (RIE) equipment to remove the SiO2 layer in the current injection area to form the insulating layer in the non-current injection area of ​​the second confinement layer.

[0092] S905 , forming a first electrode layer covering the ohmic contact layer.

[0093] In some embodiments, forming a first electrode layer covering the ohmic contact layer includes: forming the first electrode layer by sputtering on a surface of a sample using a magnetron sputtering device.

[0094] In some embodiments, after forming a first electrode layer covering the ohmic contact layer, the method for preparing a semiconductor laser further includes: annealing the first electrode layer.

[0095] In some embodiments, the electrode material of the first electrode layer is titanium (Ti), platinum (Pt), and gold (Au).

[0096] In some embodiments, forming a first electrode layer covering the ohmic contact layer includes: forming an electrode layer only in the current injection region to obtain the first electrode layer covering the ohmic contact layer.

[0097] In some embodiments, forming a first electrode layer covering the ohmic contact layer includes: forming electrode layers in the current injection region and the non-current injection region to obtain the first electrode layer covering the ohmic contact layer.

[0098] In some embodiments, after forming the electrode layer in the current injection region and the non-current injection region, the method further includes: removing the electrode layer in the non-current injection region to obtain a first electrode layer covering the ohmic contact layer.

[0099] S906 , forming the second electrode layer on the second surface of the substrate.

[0100] In some embodiments, forming the second electrode layer on the second surface of the substrate includes: evaporating the second electrode layer on the second surface of the substrate using a magnetron sputtering device.

[0101] In some embodiments, the second electrode layer is made of nickel (Ni), gold-germanium alloy (AuGe), and gold (Au).

[0102] In some embodiments, before forming the second electrode layer on the second surface of the substrate, the method for preparing the semiconductor laser provided in the above embodiment further includes:

[0103] The second surface of the substrate is thinned and polished to reduce the thickness of the semiconductor laser to 80 to 130 microns.

[0104] For example, the semiconductor laser may be thinned to a thickness of 100 to 120 micrometers by performing a thinning and polishing process on the second surface of the substrate.

[0105] In some embodiments, after the second electrode layer is formed on the second surface of the substrate, the method for preparing the semiconductor laser provided in the above embodiment may further include: chip bar cleavage, cavity surface passivation / coating and other preparation processes, which are not limited in the embodiments of the present application.

[0106] The process flow of the semiconductor laser manufacturing method provided in the above embodiment is similar to the conventional wide-strip semiconductor laser manufacturing process. It is only necessary to add the process flow of forming at least one mode loss structure at the peak position of the high-order mode of the semiconductor laser. Therefore, the above embodiment can reduce the impact of process changes on laser manufacturing.

[0107] Figure 10 A schematic diagram of a scene of laser projection display in some embodiments of the present application is shown. The scene of laser projection display includes: a laser projection device 100, a projection medium 200, a mobile terminal 300 and a control device 400. The projection of the laser projection area of ​​the laser projection device 100 is consistent with the display surface of the projection medium 200. The laser projection device 100 can be connected to a computer, a broadcasting network, the Internet, a video high-density optical disc (Video Compact Disc, VCD), a digital video disc (Digital Versatile Disc Recordable, DVD), a game console, a DV and other devices through different interfaces to receive projection content such as images, videos, texts, etc., and project the projection content onto the projection medium 200 formed by a physical entity such as a wall, a curtain, or a screen. The user can operate the laser projection device 100 through the mobile terminal 300 or the control device 400 to achieve control of the laser projection device 100. The laser projection device 100 may be a laser TV host, the projection medium 200 may be a laser TV screen, and the control device 400 may be a remote controller. Communication between the remote controller and the laser projection device 100 may include infrared protocol communication, Bluetooth protocol communication, wireless or other wired methods to control the laser projection device 100. The user may control the laser projection device 100 by inputting user commands through physical buttons on the remote controller, voice input, a control panel, etc.

[0108] Reference Figure 11 As shown, Figure 11 A schematic diagram of the structure of the laser projection device 100 in some embodiments of the present application. Figure 11 As shown, the laser projection device 100 includes: a display control component 111 , a light source driving component 112 , a laser light source 113 , a light valve 114 and a lens 115 .

[0109] In which, the display control component 111 is respectively connected to the light source driving component 112 and the light valve 114, and the light source driving component 112 is connected to the laser light source 113; the laser light source includes the semiconductor laser provided in any of the above embodiments or a semiconductor laser prepared by the preparation method of the semiconductor laser provided in any of the above embodiments.

[0110] Reference Figure 12 As shown, in some embodiments, the laser projection device 100 further includes: at least one of a controller 121, a tuner and demodulator 122, a communicator 123, an external device interface 124, an audio output interface 125, a memory 126, a power supply, and a user interface.

[0111] In some embodiments, controller 121 includes at least one of a central processing unit (CPU), a video processor, an audio processor, a graphics processing unit (GPU), random access memory (RAM), read-only memory (ROM), first through nth interfaces for input / output, and a communication bus. Controller 121 controls the operation of the laser projection device and responds to user operations via various software control programs stored in memory 126. Controller 121 controls the overall operation of the projection device.

[0112] The tuner-demodulator 122 receives broadcast television signals via wired or wireless reception, and demodulates audio and video signals, such as EPG data signals, from a plurality of wireless or wired broadcast television signals.

[0113] The communicator 123 is a component for communicating with external devices or servers according to various communication protocols. For example, the communicator may include at least one of a Wi-Fi module, a Bluetooth module, a wired Ethernet module, or other network communication protocol chips or a near-field communication protocol chip, and an infrared receiver.

[0114] The external device interface 124 may include, but is not limited to, any one or more of the following: a high-definition multimedia interface (HDMI), an analog or digital high-definition component input interface (component), a composite video input interface (CVBS), a USB input interface (USB), an RGB port, etc. It may also be a composite input / output interface formed by multiple of the above interfaces.

[0115] The audio output interface 125 is an interface for outputting audio information. The audio output interface 125 may include, but is not limited to, a microphone interface, an earphone interface, and the like.

[0116] Reference Figure 13 and Figure 14 As shown, the laser light source 113 further includes: a bottom plate 131, a tube wall 132, at least one reflecting prism 133, a heat sink 134, a transparent sealing glass 135 and a collimating lens group 136;

[0117] The semiconductor laser 137 is welded to the heat sink 134. The tube wall 132, the semiconductor laser 137 and the reflecting prism 133 are all fixed to the base plate 131. The semiconductor laser 137 and the reflecting prism 133 are surrounded by the tube wall 132. The transparent sealing glass 135 is sealed on the tube wall 132. The collimating lens group 136 covers the transparent sealing glass 135. The laser light emitted by the semiconductor laser 137 is reflected in a direction away from the base plate 131 via the reflecting prism 133. The reflected laser light is emitted perpendicular to the base plate 131 via the collimating lens group 136.

[0118] In some embodiments, an embodiment of the present application provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a computing device, the computing device implements the method for preparing a semiconductor laser described in any of the above embodiments.

[0119] In some embodiments, embodiments of the present application provide a computer program product, which, when executed on a computer, enables the computer to implement the method for preparing a semiconductor laser as described in any of the above embodiments.

[0120] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application 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 or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

[0121] For ease of explanation, the above description has been made with reference to specific embodiments. However, the above exemplary discussion is not intended to be exhaustive or to limit the embodiments to the specific forms disclosed above. Based on the above teachings, various modifications and variations are possible. The above embodiments are selected and described to better explain the principles and practical applications, so that those skilled in the art can better utilize the embodiments and various different variations of the embodiments suitable for specific use considerations.

Claims

1. A semiconductor laser, characterized in that include: substrate; an epitaxial layer, the epitaxial layer being located on the first surface of the substrate; The epitaxial layer includes a buffer layer, a first confinement layer, a first waveguide layer, an active layer, a second waveguide layer, and a second confinement layer stacked in sequence; the epitaxial layer also includes: an insulating layer located on a side of the second confinement layer away from the substrate and covering a non-current injection region, and an ohmic contact layer located on a side of the second confinement layer away from the substrate and covering a current injection region; a first electrode layer, the first electrode layer being located on a side of the epitaxial layer away from the substrate; a second electrode layer, the second electrode layer being located on the second surface of the substrate; At least one mode loss structure is located at a peak position of a high-order mode of the semiconductor laser, and the mode loss structure includes a blind hole extending from the second electrode layer along the thickness direction of the semiconductor laser to the inside of the second confinement layer.

2. The semiconductor laser according to claim 1, wherein The distance between the bottom of the blind hole and the first surface of the second restriction layer is 20 to 50 nanometers; The first surface of the second restriction layer is a surface of the second restriction layer close to the substrate.

3. The semiconductor laser according to claim 1, wherein The blind hole has a diameter of 3 to 7 microns.

4. The semiconductor laser according to claim 1, wherein The number of the mode loss structures at the peak position of the high-order mode of the semiconductor laser is positively correlated with the offset distance of the peak position of the high-order mode of the semiconductor laser; The offset distance of the peak position of the high-order mode of the semiconductor laser is the distance from the peak position of the high-order mode of the semiconductor laser to the peak position of the fundamental mode of the semiconductor laser.

5. The semiconductor laser according to any one of claims 1 to 4, characterized in that: The substrate, the buffer layer and the first confinement layer are formed of N-type doped materials; The second confinement layer and the ohmic contact layer are formed of a P-type doped material; The first electrode layer, the second electrode layer, the first waveguide layer, the second waveguide layer, and the active layer are formed of undoped materials.

6. A method for preparing a semiconductor laser, characterized in that: For preparing a semiconductor laser according to any one of claims 1 to 5, the method comprises: forming the buffer layer, the first confinement layer, the first waveguide layer, the active layer, the second waveguide layer and the second confinement layer in sequence on the first surface of the substrate; forming the ohmic contact layer in the current injection region of the second confinement layer; forming the at least one mode loss structure at a peak position of a high-order mode of the semiconductor laser; forming the insulating layer in a non-current injection region of the second confinement layer; forming a first electrode layer covering the ohmic contact layer; The second electrode layer is formed on the second surface of the substrate.

7. The method according to claim 6, characterized in that The forming of the at least one mode loss structure at a peak position of a high-order mode of the semiconductor laser comprises: The at least one mode loss structure is formed at a peak position of a high-order mode of the semiconductor laser by dry and / or wet etching using a photoresist as a mask.

8. The method according to claim 6, characterized in that Before forming the second electrode layer on the second surface of the substrate, the method further includes: The second surface of the substrate is thinned and polished to reduce the thickness of the semiconductor laser to 80 to 130 microns.

9. A laser projection device, characterized in that: include: Display control assembly, light source driving assembly, laser light source, light valve and lens; The display control component is connected to the light source driving component and the light valve respectively, and the light source driving component is connected to the laser light source; The laser light source comprises the semiconductor laser according to any one of claims 1 to 5 or a semiconductor laser prepared by the method for preparing a semiconductor laser according to any one of claims 6 to 8.

10. The laser projection device according to claim 9, characterized in that: The laser light source further comprises: a bottom plate, a tube wall, at least one reflecting prism, a heat sink, a transparent sealing glass and a collimating lens group; The semiconductor laser is welded on the heat sink, the tube wall, the semiconductor laser and the reflective prism are all fixed on the base plate, the semiconductor laser and the reflective prism are surrounded by the tube wall, the transparent sealing glass is sealed on the tube wall, and the collimating lens group covers the transparent sealing glass; the laser light emitted by the semiconductor laser is reflected in a direction away from the base plate through the reflective prism, and the reflected laser light is emitted perpendicular to the base plate through the collimating lens group.

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