Semiconductor laser

Abstract

The semiconductor laser comprises an N-surface electrode, an N-type substrate, an N-type buffer layer, an N-type limiting layer, an N-type waveguide layer, an active layer, a P-type waveguide layer, a P-type limiting layer, an ohmic contact layer 109 and a P-surface electrode which are arranged in sequence, injection regions and non-injection regions are arranged in the P-type limiting layer, the non-injection regions are arranged at the two ends of the injection regions in the direction parallel to the plane where the P-type limiting layer is located, the non-injection regions are formed by the N-type barrier layer, and the injection regions are formed by the P-type limiting layer. Based on the above scheme, current lateral diffusion can be prevented or at least weakened, accumulation of current carriers can be inhibited, the injection efficiency of the current can be improved, and high-power, low-current threshold and conversion rate output can be realized; therefore, the near-field / far-field divergence angle of the semiconductor laser can be reduced to a certain extent, and the light beam quality and brightness of the semiconductor laser are improved.

Description

Technical Field

[0001] The present application relates to the technical field of display devices, and in particular to a semiconductor laser. Background Art

[0002] Wide stripe high-power laser diode (WS-HPLD) is widely used in various fields due to its advantages such as wide output band coverage, high output power, small size and long life. With the continuous expansion of application fields, higher requirements are put forward for its output power and electro-optical conversion efficiency. At present, the output power of a single tube of wide stripe semiconductor laser has reached tens of watts. In addition, for some fields, WS-HPLD is also required to be able to take into account high brightness output at the same time, such as fiber coupling, laser projection, optical communication, laser medical treatment and scientific research.

[0003] In order to achieve high-power output of the laser, a wide strip structure is usually used. The lateral current diffusion and carrier accumulation at the edge of the strip of this type of semiconductor laser will reduce the beam quality of the laser. Utility Model Content

[0004] In a first aspect, the present application provides a semiconductor laser, comprising an N-side electrode, an N-type substrate, an N-type buffer layer, an N-type confinement layer, an N-type waveguide layer, an active layer, a P-type waveguide layer, a P-type confinement layer, an ohmic contact layer 109 and a P-side electrode arranged in sequence;

[0005] An injection region and a non-injection region are arranged in the P-type restriction layer. In a direction parallel to the plane where the P-type restriction layer is located, the non-injection region is arranged at both ends of the injection region. The non-injection region is formed by an N-type barrier layer, and the injection region is formed by the P-type restriction layer.

[0006] In the above scheme, the present application forms a non-injection region by inserting an N-type barrier layer into a P-type restriction layer, thereby achieving the purpose of forming a reverse PN junction barrier bar. This structure can limit the current in the injection region while preventing or at least weakening the lateral diffusion of the current, inhibiting the accumulation of carriers, improving the injection efficiency of the current, and achieving high power, low current threshold, and conversion rate output. Since the accumulation of carriers in the non-injection region is weakened, the near-field / far-field divergence angle of the semiconductor laser can be reduced to a certain extent, thereby improving the beam quality and brightness of the semiconductor laser. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 A schematic diagram of a semiconductor laser epitaxial layer structure provided for one or more embodiments of the present application;

[0008] Figure 2A schematic diagram of another semiconductor laser epitaxial layer structure provided for one or more embodiments of the present application;

[0009] Figure 3 A schematic diagram of an N-type barrier epitaxial layer structure provided for one or more embodiments of the present application;

[0010] Figure 4 A schematic diagram of another semiconductor laser epitaxial layer structure provided in an embodiment of the present application;

[0011] Figure 5 A schematic diagram of another semiconductor laser epitaxial layer structure provided for one or more embodiments of the present application;

[0012] Figure 6 A schematic diagram of another semiconductor laser epitaxial layer structure provided for one or more embodiments of the present application;

[0013] Figure 7 A schematic diagram of another semiconductor laser epitaxial layer structure provided for one or more embodiments of the present application;

[0014] Figure 8 A schematic diagram of another semiconductor laser epitaxial layer structure provided for one or more embodiments of the present application;

[0015] Fig. 9 A schematic diagram of another semiconductor laser epitaxial layer structure provided for one or more embodiments of the present application;

[0016] Fig.10 A schematic diagram of another semiconductor laser epitaxial layer structure provided for one or more embodiments of the present application;

[0017] Fig.11 A schematic diagram of another semiconductor laser epitaxial layer structure provided for one or more embodiments of the present application;

[0018] Fig.12 A schematic diagram of another semiconductor laser epitaxial layer structure provided for one or more embodiments of the present application;

[0019] Fig.13 A schematic diagram of another semiconductor laser epitaxial layer structure provided for one or more embodiments of the present application;

[0020] Fig.14 A schematic diagram of another semiconductor laser epitaxial layer structure provided for one or more embodiments of the present application;

[0021] Fig.15 A schematic diagram of another semiconductor laser epitaxial layer structure provided for one or more embodiments of the present application;

[0022] Fig.16A schematic diagram of another semiconductor laser epitaxial layer structure provided for one or more embodiments of the present application;

[0023] Fig.17 A schematic diagram of another semiconductor laser epitaxial layer structure provided for one or more embodiments of the present application;

[0024] Fig.18 A schematic diagram of another semiconductor laser epitaxial layer structure provided for one or more embodiments of the present application;

[0025] Fig.19 A schematic diagram of another semiconductor laser epitaxial layer structure provided for one or more embodiments of the present application;

[0026] Fig. 20 A schematic diagram of another semiconductor laser epitaxial layer structure provided for one or more embodiments of the present application;

[0027] Fig.21 A schematic diagram of another semiconductor laser epitaxial layer structure provided for one or more embodiments of the present application. DETAILED DESCRIPTION

[0028] In order to make the purpose and implementation method of the present application clearer, the exemplary implementation method of the present application will be clearly and completely described below in conjunction with the drawings in the exemplary embodiments of the present application. Obviously, the described exemplary embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0029] It should be noted that the brief description of terms in this application is only for the convenience of understanding the embodiments described below, and is not intended to limit the embodiments of this application. Unless otherwise specified, these terms should be understood according to their common and usual meanings.

[0030] The terms "first", "second", "third", etc. in the specification and claims of this application and the above drawings are used to distinguish similar or similar objects or entities, and do not necessarily mean to limit a specific order or sequence, unless otherwise noted. It should be understood that the terms used in this way can be interchangeable under appropriate circumstances.

[0031] The terms "comprises," "comprising," and "having," 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.

[0032] Wide stripe high-power laser diode (WS-HPLD) is widely used in various fields due to its advantages such as wide output band coverage, high output power, small size and long life. With the continuous expansion of application fields, higher requirements are put forward for its output power and electro-optical conversion efficiency. At present, the output power of a single tube of wide stripe semiconductor laser has reached tens of watts. In addition, for some fields, WS-HPLD is also required to be able to take into account high brightness output at the same time, such as fiber coupling, laser projection, optical communication, laser medical treatment and scientific research.

[0033] In order to achieve high-power output of semiconductor lasers, a wide strip structure is usually used. However, the light intensity distribution of this type of semiconductor laser in the far field is extremely asymmetric, and the spot is a narrow ellipse. This is mainly because the active area material of WS-HPLD has a strong refractive index restriction in the fast axis direction, and its beam divergence angle and beam width change little, and the beam quality is relatively stable; while the active area material has a weak refractive index restriction in the slow axis direction, and its beam divergence angle and beam width are easily affected by temperature changes, resulting in an increase in the slow axis divergence angle of the semiconductor laser, which leads to low beam quality output by WS-HPLD, bringing certain difficulties to the practical application of semiconductor lasers.

[0034] The lateral beam quality of the laser can be expressed by equation (1):

[0035] B lat =P / BPP lat (1)

[0036] BPP lat =0.25*ω 95％ *θ 95％ (2)

[0037] Where P represents output power, BPP lat Side beam parameter product, ω 95％ and θ 95％ They respectively represent the near-field width and far-field horizontal divergence angle when the light field energy is 95%.

[0038] In addition to the thermal lens effect, the lateral diffusion of current and accumulation of carriers at the edge of the strip will also reduce the beam quality of the laser. Domestic and foreign researchers have conducted research in different directions on this issue, with the aim of improving the beam quality of semiconductor lasers without changing the light output power, so as to improve the brightness of semiconductor lasers. For example, defects are introduced through high-energy deep ion implantation technology to limit the diffusion and accumulation of the injected current on the P side of the strip edge, thereby reducing the near / far field divergence angle and improving the beam quality. However, this method will introduce larger defects and seriously affect the output power and conversion efficiency of semiconductor lasers. The ridge structure laser currently used generally forms a refractive index guiding structure through deep etching. Although it can limit carriers to the strip injection area and improve the output power and conversion efficiency, the larger refractive index difference will reduce the beam quality. The buried structure grows high-bandgap waveguide layer materials on both sides of the current injection area through secondary epitaxial growth to form a built-in refractive index guiding structure, which weakens the lateral diffusion of current and carrier accumulation, thereby improving the output power and conversion efficiency. Similar to the ridge structure, the large refractive index difference will cause the existence of multiple high-order modes, reducing the quality of the beam output.

[0039] From the perspective of the different structures and processes currently used, it is impossible to simultaneously improve the beam quality and brightness of semiconductor lasers without changing the optical output power.

[0040] Based on the above problems, the present invention provides a semiconductor laser. Figure 1 A schematic diagram of a semiconductor laser epitaxial layer structure provided for one or more embodiments of the present application, the semiconductor laser comprises an N-side electrode 101, an N-type substrate 102, an N-type buffer layer 103, an N-type confinement layer 104, an N-type waveguide layer 105, an active layer 106, a P-type waveguide layer 107, a P-type confinement layer 108, an ohmic contact layer 109 and a P-side electrode 110 arranged in sequence. An injection region 200 and a non-injection region 300 are arranged in the P-type confinement layer 108, and the non-injection region 300 is arranged at both ends of the injection region 200 in a direction parallel to the plane where the P-type confinement layer 108 is located, and the non-injection region 300 is formed by the N-type barrier layer 111, and the injection region 200 is formed by the P-type confinement layer 108.

[0041] like Figure 1As shown, the N-type substrate 102, the N-type buffer layer 103 and the N-type limiting layer 104 in the embodiment of the present application are formed of N-type doped materials, the P-type limiting layer 108, the ohmic contact layer 109 and are formed of P-type doped materials, the N-type waveguide layer 105 and the P-type waveguide layer 107 are used to reduce photon absorption and loss, the undoped active layer 106 is not doped, and the N-type barrier layer 111 is formed of N-type doped materials. It should be noted that in the embodiment of the present application and the actual application scenario, the thickness difference between each epitaxial layer may be large, and in the illustration of the embodiment of the present application, in order to relatively clearly reflect the structure of each epitaxial layer, the thickness ratio between some epitaxial layers may be distorted, but the thickness of each epitaxial layer can be described in the embodiment of the present application in text, and the drawings are only used as examples.

[0042] In the above embodiment, the present application actually inserts a layer structure of N-type doping material into the P-type confinement layer 108, that is, a reverse PN junction is formed in the original semiconductor laser structure. This structure can limit the current to the injection region 200 while preventing or at least weakening the lateral diffusion of the current, inhibiting the accumulation of carriers, improving the injection efficiency of the current, and achieving high power, low current threshold, and conversion rate output. Since the accumulation of carriers in the non-injection region 300 is weakened, the near-field / far-field divergence angle of the semiconductor laser can be reduced to a certain extent, thereby improving the beam quality and brightness of the semiconductor laser.

[0043] Figure 2 A schematic diagram of another semiconductor laser epitaxial layer structure provided for one or more embodiments of the present application, in some embodiments, the N-type barrier layer 111 includes an N-type etch barrier layer 1111 and an N-type doped barrier layer 1112, and the N-type doped barrier layer 1112 is located on the side of the N-type etch barrier layer 1111 away from the P-type waveguide layer 107. The N-type etch barrier layer 1111 and the N-type doped barrier layer 1112 are made of different materials, the N-type doped barrier layer 1112 is used to block current, and the N-type etch barrier layer 1111 is used to block etching materials.

[0044] In the embodiment of the present application, the injection region 200 and the non-injection region 300 can be formed by etching the etching material. The materials of the N-type etching barrier layer 1111 and the N-type doped barrier layer 1112 are different. The same etching material cannot etch the N-type etching barrier layer 1111 and the N-type doped barrier layer 1112 formed by the two materials. Therefore, the purpose of better etching the N-type etching barrier layer 1111 and the N-type doped barrier layer 1112 to form a better injection region 200 and non-injection region 300 can be achieved.

[0045] Figure 3A schematic diagram of an N-type barrier layer structure provided for one or more embodiments of the present application, in some embodiments, the thickness H1 of the N-type etch barrier layer 1111 is greater than or equal to 15 nm, and / or less than or equal to 25 nm. The thickness H2 of the N-type doping barrier layer 1112 is greater than or equal to 30 nm, and / or less than or equal to 50 nm.

[0046] Exemplarily, a smaller thickness of the N-type doped barrier layer 1112 has a weaker blocking effect on the current, while a larger thickness of the N-type doped barrier layer 1112 will result in a poor flatness on the side of the N-type doped barrier layer 1112 away from the N-type etching barrier layer 1111, which is not conducive to the output of semiconductor laser characteristics. Therefore, the thickness of the N-type doped barrier layer 1112 may be greater than or equal to 30 nm, or less than or equal to 50 nm. A smaller thickness of the N-type etching barrier layer 1111 may result in an inability to form a better blocking effect on the etching material, while a larger thickness of the N-type etching barrier layer 1111 will also affect the flatness of the side of the N-type etching barrier layer 1111 facing the N-type doped barrier layer 1112, thereby affecting the output of semiconductor laser characteristics.

[0047] In the embodiment of the present application, the thickness of the N-type doped barrier layer 1112 is greater than the thickness of the N-type etch barrier layer 1111. If the thickness ratio between the N-type doped barrier layer 1112 and the N-type etch barrier layer 1111 is too large, it may cause the overall voltage of the semiconductor laser to increase, which is not conducive to the output of the semiconductor laser characteristics. Preferably, the thickness ratio between the N-type doped barrier layer 1112 and the N-type etch barrier layer 1111 can be 2:1.

[0048] In some embodiments, the material of the N-type etch stop layer 1111 includes GaInP, the doping source of the N-type etch stop layer 1111 includes Si2H6, and the doping concentration of Si2H6 is greater than or equal to 1.5E18 / cm 3 , and / or less than or equal to 3.5E18 / cm 3 .

[0049] The material of the N-type doped barrier layer 1112 includes GaAs, and the doping source of the N-type etching barrier layer 1111 includes Si2H6, and the doping concentration of Si2H6 is greater than or equal to 1.5E18 / cm 3 , and / or less than or equal to 3.5E18 / cm 3 .

[0050] Specifically, the N-type etch stop layer 1111 and the N-type doping stop layer 1112 may be formed of different materials, but both are N-type doped materials. The material of the N-type etch stop layer 1111 may be GaInP. More specifically, GaInP may be described as Ga x1 In 1-x1P, where x1 represents the composition ratio of Ga element in GaInP, 1-x1 represents the composition ratio of In element in GaInP, and Ga x1 In 1-x1 P indicates that the ratio of Ga element, In element and P element in GaInP is x1:(1-x1):1, wherein x1<1.

[0051] The doping source of the N-type doping barrier layer 1112 and the N-type etching barrier layer 1111 can be Si element. When the doping concentration is too low, the blocking effect on the current is weak. When the doping concentration is too high, it is easy to cause the failure of the semiconductor laser. After research, it is found that the doping concentration of Si element can be greater than or equal to 1.5E18 / cm 3 , or less than or equal to 3.5E18 / cm 3 , thereby achieving the purpose of both better blocking the current and preventing the semiconductor laser from failing.

[0052] In some embodiments, the ratio of Ga element, In element and P element in the GaInP material is x1:(1-x1):1, wherein x1 is greater than or equal to 0.48 and / or less than or equal to 0.52.

[0053] For example, the Ga content of the GaInP material may be greater than or equal to 48%, or less than or equal to 52%, that is, the In content may be greater than or equal to 48%, or less than or equal to 52%.

[0054] Exemplarily, the P-type confinement layer 108 and the N-type barrier layer 111 are formed by secondary epitaxy. The Al content in the P-type confinement layer 108 is lower than the Al content in the P-type waveguide layer 107, or the P-type confinement layer 108 does not include Al.

[0055] In the embodiment of the present application, the P-type restriction layer 108 and the N-type barrier layer 111 are prepared based on the secondary epitaxial method. Specifically, in the process of preparing the P-type restriction layer 108 and the N-type restriction layer 104, in order to set the N-type restriction layer 104 in the P-type restriction layer 108, the P-type restriction layer 108 can be prepared in two steps.

[0056] The P-type confinement layer 108 may include a P-type lower confinement layer 1081 and a P-type upper confinement layer 1082. In the embodiment of the present application, the P-type lower confinement layer 1081 may be prepared first, and then the N-type confinement layer 104 may be prepared, and the injection region 200 and the non-injection region 300 may be formed, and then the P-type upper confinement layer 1082 may be prepared. Based on the above scheme, the P-type confinement layer 108 and the N-type barrier layer 111 may be prepared by secondary epitaxy.

[0057] After the preparation of the P-type lower confinement layer 1081 is completed, the unfinished semiconductor laser needs to be taken out from the relevant equipment and exposed to the air, and then transferred to the relevant equipment for preparing the N-type confinement layer 104. In this process, if the P-type confinement layer 108 contains Al elements, it will undergo an oxidation reaction with the O element in the air, thereby causing oxidation damage to the P-type confinement layer 108, affecting the overall performance of the semiconductor laser.

[0058] Specifically, oxidation of the Al element produces Al2O3 with a high refractive index, which leads to the formation of additional light scattering centers, increased optical losses, and reduced internal reflection efficiency and beam quality of semiconductor lasers.

[0059] Al2O3 has absorption properties for certain wavelengths of light and may therefore cause additional light absorption, which will reduce the optical power that can propagate through the waveguide and reach the threshold oscillation.

[0060] Al2O3 may destroy the original semiconductor heterojunction structure, affect the effective injection and recombination of carriers, and further reduce the working efficiency and stability of semiconductor lasers.

[0061] The heat generated by the oxidation process and the resulting increase in light absorption may cause local temperature increases, aggravating thermal effects, causing the operating point of the semiconductor laser to deviate from the optimal state and may even lead to thermal collapse.

[0062] In the embodiment of the present application, the P-type confinement layer 108 does not include the Al element, so the above-mentioned problem can be avoided directly from the source.

[0063] Alternatively, since the P-type waveguide layer 107 is the area where the semiconductor laser light field is mainly concentrated, if the Al element content in the P-type confinement layer 108 is lower than the Al element content in the P-type waveguide layer 107, compared to setting the N-type barrier layer 111 in the P-type waveguide layer 107, the above problem can be alleviated to a certain extent.

[0064] Figure 4 A schematic diagram of another semiconductor laser epitaxial layer structure provided in an embodiment of the present application. In some embodiments, the material of the N-type substrate 102 includes GaAs.

[0065] The material of the N-type buffer layer 103 includes GaAs, the doping source of the N-type buffer layer 103 includes Si2H6, and the thickness of the N-type buffer layer 103 is greater than or equal to 0.35 μm and / or less than or equal to 0.5 μm.

[0066] The material of the N-type confinement layer 104 includes AlInP, the doping source of the N-type confinement layer 104 includes Si2H6, and the thickness of the N-type confinement layer 104 is greater than or equal to 0.9 μm and / or less than or equal to 1 μm.

[0067] The material of the N-type waveguide layer 105 includes AlGaInP, the N-type waveguide layer 105 is not doped, and the thickness of the N-type waveguide layer 105 is greater than or equal to 100 nm and / or less than or equal to 200 nm.

[0068] The active layer 106 includes a first barrier layer 1061, a quantum well layer 1062, and a second barrier layer 1063, which are sequentially arranged in a direction away from the N-type waveguide layer 105. The material of the first barrier layer 1061 includes AlGaInP, the first barrier layer 1061 is not doped, and the thickness of the first barrier layer 1061 is greater than or equal to 8nm, and / or less than or equal to 15nm. The material of the quantum well layer 1062 includes GaInP, the quantum well layer 1062 is not doped, and the thickness of the quantum well layer 1062 is greater than or equal to 7nm, and / or less than 13nm. The material of the second barrier layer 1063 includes AlGaInP, and the thickness of the second barrier layer 1063 is greater than or equal to 8nm, and / or less than or equal to 15nm.

[0069] The material of the P-type waveguide layer 107 includes AlGaInP, the P-type waveguide layer 107 is not doped, and the thickness of the P-type waveguide layer 107 is greater than or equal to 100 nm and / or less than or equal to 200 nm.

[0070] The P-type confinement layer 108 includes a P-type lower confinement layer 1081 and a P-type upper confinement layer 1082. The P-type upper confinement layer 1082 is arranged on a side of the P-type lower confinement layer 1081 away from the P-type waveguide layer 107, and the N-type barrier layer 111 is arranged between the P-type lower confinement layer 1081 and the P-type upper confinement layer 1082. The material of the P-type lower confinement layer 1081 includes AlGaP, the doping source of the P-type lower confinement layer 1081 includes Cp2Mg or DEZn, and the thickness of the P-type lower confinement layer 1081 is greater than or equal to 0.3μm, and / or less than or equal to 0.7μm. The material of the P-type upper confinement layer 1082 includes AlInP, the doping source of the P-type upper confinement layer 1082 includes Cp2Mg or DEZn, the thickness of the P-type upper confinement layer 1082 is greater than or equal to 0.2μm, and / or the thickness of the P-type upper confinement layer 1082 is less than or equal to 0.6μm.

[0071] The material of the ohmic contact layer 109 includes GaAs, the doping source of the ohmic contact layer 109 includes CBr4, and the thickness of the ohmic contact layer 109 is greater than or equal to 0.2 μm and / or less than or equal to 0.3 μm.

[0072] First, the semiconductor laser provided in the embodiments of the present application may be a semiconductor laser of various wavelength bands, including but not limited to GaAs, GaN, InP and other substrates.

[0073] The following is an exemplary process for preparing a semiconductor laser provided in an embodiment of the present application:

[0074] After the N-type GaAs substrate 102 is placed in MOCVD for surface heat treatment, an N-type buffer layer 103, an N-type confinement layer 104, an N-type waveguide layer 105, an active layer 106, a P-type waveguide layer 107, a P-type lower confinement layer 1081, an N-type etch barrier layer 1111, and an N-type doped barrier layer 1112 are grown in sequence to complete the first epitaxial growth, and the current injection region 200 is prepared by a non-in-situ etching method, and then a P-type upper confinement layer 1082 and an ohmic contact layer 109 are grown.

[0075] The active layer 106 includes 1 to 3 quantum well layers 1062 and barrier layers on both sides thereof. The material of the N-type confinement layer 104 can be specifically represented by Al x2 In 1-x2 The material of the P, N type waveguide layer 105 can be specifically expressed as (Al x3 Ga 1-x3 ) y1 In 1-y1 P, the material of the active layer 106 can be specifically represented by Ga x4 In 1-x4 P / (Al x5 Ga 1-x5 ) y2 In 1-y2 The material of the P-type waveguide layer 107 can be specifically expressed as (Al x6 Ga 1-x6 ) y3 In 1-y3 P, the material of the P-type lower limiting layer 1081 can be specifically expressed as Al x7 In 1-x7 The material of the P, N-type etching stopper layer 1111 can be specifically represented by Ga x1 In 1-x1 P, the material of the P-type upper confinement layer 1082 can be specifically expressed as Al x8 In 1-x8 P.

[0076] Among them, 0.48≤x2≤0.52, 0.4≤x3≤0.9, 0.4≤y1≤0.6, 0.35≤x4≤0.55, 0.3≤x5≤0.62, 0.4≤y2≤0.6, 0.4≤x6≤0.9, 0.4≤y3≤0.6, 0.48≤x7≤0.52, 0.1≤x1≤0.9, 0.48≤x8≤0.52, x7≤x8.

[0077] Specifically,

[0078] First, an N-type substrate 102 is provided, such as Figure 5A schematic diagram of another semiconductor laser epitaxial layer structure provided for one or more embodiments of the present application.

[0079] The N-type GaAs substrate 102 is placed in MOCVD and the temperature in the chamber is raised to 710±20° C. in a H 2 atmosphere for baking. Then, AsH 3 is introduced to perform surface heat treatment on the N-type substrate 102 .

[0080] The temperature is slowly lowered to 680±10°C, TMGa and AsH3 are introduced, and an N-type buffer layer 103 is grown on the N-type substrate 102. The thickness of the N-type buffer layer 103 can be greater than or equal to 0.35 μm, or less than or equal to 0.5 μm. The doping source is Si2H6, and the doping concentration can be greater than or equal to 1.5E18 / cm 3 , or less than or equal to 2.5E18 / cm 3 , which is N-type doping. The purpose of the N-type buffer layer 103 is to prevent the influence of the substrate's own defects on the epitaxial layer growth and provide a good growth interface and growth quality. Figure 6 A schematic diagram of another semiconductor laser epitaxial layer structure provided for one or more embodiments of the present application.

[0081] The temperature is slowly raised to 700±10℃, TMGa, TMAl and PH3 are introduced, and AsH3 is stopped until the As atoms in the cavity are exhausted. An N-type confinement layer 104 is grown on the N-type buffer layer 103. The thickness of the N-type confinement layer 104 can be greater than or equal to 0.9μm or less than or equal to 1μm. The doping source is Si2H6, and the doping concentration can be greater than or equal to 4E17 / cm 3 , or less than or equal to 2E18 / cm 3 , is N-type doping. Figure 7 A schematic diagram of another semiconductor laser epitaxial layer structure provided for one or more embodiments of the present application.

[0082] The growth temperature is maintained at 700±10°C, TMGa, TMAl, TMIn and PH3 are introduced, and an N-type waveguide layer 105 is grown on the N-type confinement layer 104. The thickness of the N-type waveguide layer 105 can be greater than or equal to 100nm, or less than or equal to 200nm. The N-type waveguide layer 105 is used to transmit light beams, and the N-type waveguide layer 105 is not doped to achieve the purpose of reducing photon absorption and loss. Figure 8 A schematic diagram of another semiconductor laser epitaxial layer structure provided for one or more embodiments of the present application.

[0083] The temperature is slowly lowered to 640±10°C, TMGa, TMAl, TMIn and PH3 are introduced, and a first barrier layer 1061 is grown on the N-type waveguide layer 105. The thickness of the first barrier layer 1061 can be greater than or equal to 8nm, or less than or equal to 15nm. The first barrier layer 1061 is not doped. Fig. 9 A schematic diagram of another semiconductor laser epitaxial layer structure provided for one or more embodiments of the present application.

[0084] The growth temperature is maintained at 640±10°C, TMGa, TMIn and PH3 are introduced, and a quantum well layer 1062 is grown on the first barrier layer 1061. The thickness of the quantum well layer 1062 can be greater than or equal to 7nm, or less than or equal to 13nm. The quantum well layer 1062 is not doped. Fig.10 A schematic diagram of another semiconductor laser epitaxial layer structure provided for one or more embodiments of the present application.

[0085] The growth temperature is maintained at 640±10°C, TMGa, TMAl, TMIn and PH3 are introduced, and a second barrier layer 1063 is grown on the quantum well layer 1062. The thickness of the second barrier layer 1063 can be greater than or equal to 8nm, or less than or equal to 15nm. The second barrier layer 1063 is not doped. Fig.11 A schematic diagram of another semiconductor laser epitaxial layer structure provided for one or more embodiments of the present application.

[0086] The temperature is slowly raised to 700±10°C, TMGa, TMAl, TMIn and PH3 are introduced, and a P-type waveguide layer 107 is grown on the second barrier layer 1063. The thickness of the P-type waveguide layer 107 can be greater than or equal to 100nm, or less than or equal to 200nm. The P-type waveguide layer 107 is not doped to reduce photon absorption and loss. Fig.12 A schematic diagram of another semiconductor laser epitaxial layer structure provided for one or more embodiments of the present application.

[0087] The growth temperature is maintained at 700±10°C, TMGa, TMAl and PH3 are introduced, and a P-type lower confinement layer 1081 is grown on the P-type waveguide layer 107. The thickness of the P-type lower confinement layer 1081 can be greater than or equal to 0.3nm, or less than or equal to 0.7μm. The doping source is Cp2Mg or DEZn, and the doping concentration can be greater than or equal to 4E17 / cm 3 , or less than or equal to 2E18 / cm 3 , is P-type doping. Fig.13 A schematic diagram of another semiconductor laser epitaxial layer structure provided for one or more embodiments of the present application.

[0088] The growth temperature is maintained at 700±10°C, TMGa, TMIn and PH3 are introduced, and an N-type etching stopper layer 1111 is grown on the P-type lower limiting layer 1081. The thickness of the N-type etching stopper layer 1111 can be greater than or equal to 15nm, or less than or equal to 25nm. The doping source is Si2H6, and the doping concentration can be greater than or equal to 1.5E18 / cm 3 , or less than or equal to 3.5E18 / cm 3 , is N-type doping. Fig.14 A schematic diagram of another semiconductor laser epitaxial layer structure provided for one or more embodiments of the present application.

[0089] The growth temperature is maintained at 700±10°C, TMGa and AsH3 are introduced, and an N-type doped barrier layer 1112 is grown on the N-type etching barrier layer 1111. The thickness of the N-type doped barrier layer 1112 can be greater than or equal to 30nm, or less than or equal to 50nm. The doping source is Si2H6, and the doping concentration can be greater than or equal to 1.5E18 / cm 3 , or less than or equal to 3.5E18 / cm 3 , is N-type doping. Fig.15 A schematic diagram of another semiconductor laser epitaxial layer structure provided for one or more embodiments of the present application. At this point, the first epitaxial growth is completed, and then the primary epitaxial wafer (the unfinished semiconductor laser) is taken out, and a SiO2 film is grown on the primary epitaxial wafer using PECVD as a mask protection layer, and the current injection region 200 is prepared by etching through photolithography and ICP etching / wet etching methods. Since the structure contains an N-type etching barrier layer 1111, which is a different material from the N-type doped barrier layer 1112, the same ICP etching gas / wet etching solution cannot clean both materials at the same time, so the N-type doped barrier layer 1112 and the N-type etching barrier layer 1111 can be better cleaned. After the SiO2 mask protection layer is cleaned and removed using BOE etching solution, it is immersed in a dilute HCI solution for 10 to 30 seconds to remove the oxide layer formed in the air. Fig.16 A schematic diagram of another semiconductor laser epitaxial layer structure provided for one or more embodiments of the present application.

[0090] Then, the primary epitaxial wafer is placed in MOCVD, the temperature is slowly grown to 700±10°C, TMGa, TMAl and PH3 are introduced, and a P-type upper confinement layer 1082 is grown on the N-type doped barrier layer 1112 (and the P-type lower confinement layer 1081). The thickness of the P-type upper confinement layer 1082 can be greater than or equal to 0.2μm, or less than or equal to 0.6μm; the doping source is Cp2Mg or DEZn, and the doping concentration can be greater than or equal to 4E17cm 3 , or less than or equal to 2E18 / cm 3, is P-type doping; preferably, the total thickness of the P-type lower limiting layer 1081 and the P-type upper limiting layer 1082 is 0.9 um. Fig.17 A schematic diagram of another semiconductor laser epitaxial layer structure provided for one or more embodiments of the present application.

[0091] The temperature is slowly lowered to 540±10°C, and TMGa and AsH3 are continuously introduced to grow an ohmic contact layer 109 on the P-type upper confinement layer 1082. The thickness of the ohmic contact layer 109 can be greater than or equal to 0.2 μm, or less than or equal to 0.3 μm. The doping source is CBr4, and the doping concentration can be greater than or equal to 4E18 / cm 3 , or less than or equal to 1E20 / cm 3 , is P-type doping. Fig.18 A schematic diagram of another semiconductor laser epitaxial layer structure provided for one or more embodiments of the present application.

[0092] The secondary epitaxial wafer is taken out, and an N-side electrode 101 is provided on the surface of the N-type substrate 102, and a P-side electrode 110 is provided on the surface of the ohmic contact layer 109 by photolithography and etching. Fig.19 A schematic diagram of another semiconductor laser epitaxial layer structure provided for one or more embodiments of the present application.

[0093] Thus, the preparation of the semiconductor laser can be completed.

[0094] In some embodiments, the N-type confinement layer 104 and the P-type confinement layer 108 adopt a composition gradient or doping gradient epitaxial layer structure.

[0095] Specifically, the composition gradient can represent the composition gradient between various elements in the material constituting the epitaxial layer. Taking the P-type lower confinement layer 1081 in the P-type confinement layer 108 as an example, the material of the P-type lower confinement layer 1081 can be AlInP, wherein the composition ratio between the Al element and the In element can be gradually changed in the direction perpendicular to the plane where the P-type lower confinement layer 1081 is located. The doping gradient can represent the doping concentration gradient of the doping source in the material constituting the epitaxial layer. Still taking the P-type lower confinement layer 1081 as an example, the doping source of the P-type lower confinement layer 1081 can be Cp2Mg, and the concentration of Cp2Mg can be gradually changed in the direction perpendicular to the plane where the P-type lower confinement layer 1081 is located. In this way, the optical and electrical properties of the semiconductor laser can be further improved.

[0096] In some embodiments, the N-type waveguide layer 105 and the P-type waveguide layer 107 adopt a composition-graded or doping-graded epitaxial layer structure.

[0097] Similar to the above embodiment, composition gradient or doping gradient may be applied to the N-type waveguide layer 105 and the P-type waveguide layer 107 to better improve the optical and electrical properties of the semiconductor laser, which will not be described in detail here.

[0098] In some embodiments, the N-type confinement layer 104 , the P-type confinement layer 108 , the N-type waveguide layer 105 , and the P-type waveguide layer 107 may all adopt a composition gradient or doping gradient epitaxial layer structure.

[0099] In some embodiments, an asymmetric structure may be adopted for the P-type waveguide layer 107 and the N-type waveguide layer 105 .

[0100] Fig. 20 Another schematic diagram of a semiconductor laser epitaxial layer structure provided for one or more embodiments of the present application, in some embodiments, a first bandgap transition layer 112 is disposed between the N-type buffer layer 103 and the N-type confinement layer 104. The thickness of the first bandgap transition layer 112 is greater than or equal to 20 nm, and / or less than or equal to 70 nm.

[0101] For example, the material of the first bandgap transition layer 112 may be GaInP, wherein the composition ratio of Ga element, In element and P element may be 0.5:0.5:1.

[0102] By providing the first bandgap transition layer 112 , the operating voltage of the semiconductor laser can be effectively reduced, thereby reducing the heat generated by the semiconductor laser and improving the temperature characteristics of the semiconductor laser.

[0103] Fig.21 A schematic diagram of another semiconductor laser epitaxial layer structure is provided for one or more embodiments of the present application. In some embodiments, a second bandgap transition layer 113 is arranged between the P-type confinement layer 108 and the ohmic contact layer 109, and the thickness of the second bandgap transition layer 113 is greater than or equal to 20 nm, and / or less than or equal to 50 nm.

[0104] Exemplarily, the material of the second bandgap transition layer 113 may also be GaInP, wherein the composition ratio between the Ga element, the In element and the P element may also be 0.5:0.5:1.

[0105] By providing the second bandgap transition layer 112 , the operating voltage of the semiconductor laser can be effectively reduced, thereby reducing the heat generated by the semiconductor laser and improving the temperature characteristics of the semiconductor laser.

[0106] In some embodiments, the present application may also simultaneously set a first bandgap transition layer 112 and a second bandgap transition layer 113 to improve the electrical characteristics of the semiconductor laser, which will not be described in detail here.

[0107] 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 it. 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 replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

[0108] For the convenience of explanation, the above description has been made in conjunction with specific embodiments. However, the above exemplary discussion is not intended to be exhaustive or limit the embodiments to the specific forms disclosed above. Based on the above teachings, various modifications and variations can be obtained. The selection and description of the above embodiments are to better explain the principles and practical applications, so that those skilled in the art can better use the embodiments and various different variations of the embodiments suitable for specific use considerations.

Claims

1. A semiconductor laser, characterized in that: It includes an N-side electrode, an N-type substrate, an N-type buffer layer, an N-type confinement layer, an N-type waveguide layer, an active layer, a P-type waveguide layer, a P-type confinement layer, an ohmic contact layer 109 and a P-side electrode which are arranged in sequence; An injection region and a non-injection region are arranged in the P-type restriction layer. In a direction parallel to the plane where the P-type restriction layer is located, the non-injection region is arranged at both ends of the injection region. The non-injection region is formed by an N-type barrier layer, and the injection region is formed by the P-type restriction layer.

2. The semiconductor laser according to claim 1, characterized in that The N-type barrier layer comprises an N-type etch barrier layer and an N-type doped barrier layer, wherein the N-type doped barrier layer is located on a side of the N-type etch barrier layer away from the P-type waveguide layer; The N-type etch barrier layer and the N-type doped barrier layer are made of different materials. The N-type doped barrier layer is used to block current, and the N-type etch barrier layer is used to block etching materials.

3. The semiconductor laser according to claim 2, characterized in that The thickness of the N-type etching barrier layer is greater than or equal to 15 nm, and / or less than or equal to 25 nm; the thickness of the N-type doping barrier layer is greater than or equal to 30 nm, and / or less than or equal to 50 nm.

4. The semiconductor laser according to claim 2, characterized in that The material of the N-type etching stop layer includes GaInP, and the doping source of the N-type etching stop layer includes Si2H6, and the doping concentration of Si2H6 is greater than or equal to 1.5E18 / cm 3 , and / or less than or equal to 3.5E18 / cm 3 ; The material of the N-type doped barrier layer includes GaAs, the doping source of the N-type etch barrier layer includes Si2H6, and the doping concentration of Si2H6 is greater than or equal to 1.5E18 / cm 3 , and / or less than or equal to 3.5E18 / cm 3 .

5. The semiconductor laser according to claim 4, characterized in that The ratio of Ga element, In element and P element in the GaInP material is x1:(1-x1):1; wherein x1 is greater than or equal to 0.48 and / or less than or equal to 0.

52.

6. The semiconductor laser according to claim 1, characterized in that The Al content in the P-type confinement layer is lower than the Al content in the P-type waveguide layer, or the P-type confinement layer does not include the Al element.

7. The semiconductor laser according to claim 1, characterized in that The P-type limiting layer and the N-type blocking layer are prepared based on a secondary epitaxial method.

8. The semiconductor laser according to claim 1, characterized in that The N-type confinement layer and the P-type confinement layer adopt a composition gradient or doping gradient epitaxial layer structure; and / or, The N-type waveguide layer and the P-type waveguide layer adopt a composition gradient or doping gradient epitaxial layer structure.

9. The semiconductor laser according to claim 1, characterized in that A first bandgap transition layer is disposed between the N-type buffer layer and the N-type restriction layer; the thickness of the first bandgap transition layer is greater than or equal to 20 nm, and / or less than or equal to 70 nm; and / or, A second bandgap transition layer is disposed between the P-type confinement layer and the ohmic contact layer, and a thickness of the second bandgap transition layer is greater than or equal to 20 nm and / or less than or equal to 50 nm.

10. The semiconductor laser according to claim 1, characterized in that The material of the N-type substrate includes GaAs; The material of the N-type buffer layer includes GaAs, the doping source of the N-type buffer layer includes Si2H6, and the thickness of the N-type buffer layer is greater than or equal to 0.35 μm and / or less than or equal to 0.5 μm; The material of the N-type confinement layer includes AlInP, the doping source of the N-type confinement layer includes Si2H6, and the thickness of the N-type confinement layer is greater than or equal to 0.9 μm and / or less than or equal to 1 μm; The material of the N-type waveguide layer includes AlGaInP, the N-type waveguide layer is not doped, and the thickness of the N-type waveguide layer is greater than or equal to 100 nm and / or less than or equal to 200 nm; The active layer comprises a first barrier layer, a quantum well layer and a second barrier layer which are sequentially arranged in a direction away from the N-type waveguide layer. The material of the first barrier layer comprises AlGaInP, the first barrier layer is not doped, and the thickness of the first barrier layer is greater than or equal to 8nm and / or less than or equal to 15nm; the material of the quantum well layer comprises GaInP, the quantum well layer is not doped, and the thickness of the quantum well layer is greater than or equal to 7nm and / or less than 13nm; the material of the second barrier layer comprises AlGaInP, and the thickness of the second barrier layer is greater than or equal to 8nm and / or less than or equal to 15nm; The material of the P-type waveguide layer includes AlGaInP, the P-type waveguide layer is not doped, and the thickness of the P-type waveguide layer is greater than or equal to 100 nm and / or less than or equal to 200 nm; The P-type confinement layer comprises a P-type lower confinement layer and a P-type upper confinement layer, the P-type upper confinement layer is arranged on a side of the P-type lower confinement layer away from the P-type waveguide layer, and the N-type barrier layer is arranged between the P-type lower confinement layer and the P-type upper confinement layer; the material of the P-type lower confinement layer comprises AlInP, the doping source of the P-type lower confinement layer comprises Cp2Mg or DEZn, the thickness of the P-type lower confinement layer is greater than or equal to 0.3μm, and / or less than or equal to 0.7μm; the material of the P-type upper confinement layer comprises AlInP, the doping source of the P-type upper confinement layer comprises Cp2Mg or DEZn, the thickness of the P-type upper confinement layer is greater than or equal to 0.2μm, and / or the thickness of the P-type upper confinement layer is less than or equal to 0.6μm; The material of the ohmic contact layer includes GaAs, the doping source of the ohmic contact layer includes CBr4, and the thickness of the ohmic contact layer is greater than or equal to 0.2 μm and / or less than or equal to 0.3 μm.

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