A method for manufacturing an electro-absorption modulated laser and an electro-absorption modulated laser

Abstract

The present invention relates to the field of laser manufacturing technology, and specifically to a manufacturing method of an electro-absorption modulated laser and an electro-absorption modulated laser. The manufacturing method comprises the following steps: providing a multi-quantum well structure; the multi-quantum well structure comprises an electro-absorption modulation region, a waveguide region and a laser light source region, wherein the waveguide region is located between the electro-absorption modulation region and the laser light source region; forming an isolation protection layer on the multi-quantum well structure; the isolation protection layer covers the electro-absorption modulation region and the laser light source region, and exposes the waveguide region; forming a dielectric film layer; the dielectric film layer covers the isolation protection layer of the electro-absorption modulation region and the laser light source region, and the waveguide region; annealing and mixing; annealing the multi-quantum well structure formed with the dielectric film layer. The manufacturing method of the present invention can solve the problem of the degradation of crystal quality and the damage to the epitaxial layer caused by the long-term high-temperature annealing when the quantum well mixing method is used to manufacture the InGaAlAs-based electro-absorption modulated laser in the prior art.

Description

Technical Field

[0001] The invention relates to the technical field of laser manufacturing, and in particular to a manufacturing method of an electro-absorption modulated laser and the electro-absorption modulated laser. Background Art

[0002] Electro-absorption Modulated Laser (EML) integrates a laser (usually a DFB laser light source) and an electro-absorption modulator (EAM) on a single chip. It is a high-performance communication optical chip with a small size, high integration, and low wavelength chirp. It is the preferred light source for high-speed optical communication systems at home and abroad.

[0003] For EML manufacturing, one of the most preferred active layers is the InAlGaAs-based multiple quantum well (MQW) layer. Compared with InGaAsP, InAlGaAs is widely used as an MQW material due to its larger conduction band offset and smaller valence band offset. These advantages lead to superior high-temperature performance and better extinction ratio (ER) of EAM based on InAlGaAs. However, InAlGaAs-type multiple quantum wells are not suitable for the traditional butt-joint process. The butt-joint process requires deep etching and regrowth of multiple MQW regions (such as laser light source, EAM and waveguide region). However, because aluminum-containing InGaAlAs is very easy to oxidize, it will lead to deterioration of laser performance and reduction of device reliability. In addition, the butt-joint growth process requires precise control of etching and regrowth conditions to achieve high-quality butt-joint interfaces between various integrated components, thereby reducing scattering losses. This will greatly increase the complexity of the chip manufacturing process, directly affect the yield and cost of the chip, and is not conducive to large-scale production.

[0004] A common EML manufacturing process in the prior art is quantum well intermixing (QWI). Usually, the QWI process involves the sputtering of a dielectric film after the growth of a p-type protective layer, with a thickness of more than 1µm, and requires a long period of high-temperature annealing to induce quantum well intermixing in the EAM region. This process may lead to problems such as a decrease in crystal quality and damage to the epitaxial layer due to residual defects, making it difficult to achieve large-scale repeatable production. Summary of the invention

[0005] Therefore, the present invention provides a method for manufacturing an electro-absorption modulated laser and an electro-absorption modulated laser to solve the problem of crystal quality degradation and residual defects damaging the epitaxial layer due to long-term high-temperature annealing when manufacturing InGaAlAs-based electro-absorption modulated lasers by quantum well hybridization in the prior art.

[0006] The invention provides a method for manufacturing an electro-absorption modulated laser, comprising the following steps: providing a multi-quantum well structure; the multi-quantum well structure comprising an electro-absorption modulation region, a waveguide region and a laser light source region, wherein the waveguide region is located between the electro-absorption modulation region and the laser light source region; the multi-quantum well structure at least comprising alternately stacked barrier layers and InGaAlAs quantum well layers; forming an isolation protection layer on the multi-quantum well structure; the isolation protection layer covering the electro-absorption modulation region, the laser light source region and the waveguide region; forming a dielectric film layer; the dielectric film layer covering the isolation protection layer in the electro-absorption modulation region and the laser light source region and exposing the waveguide region; during the formation of the dielectric film layer, an interface between the dielectric film layer in the waveguide region and a film layer thereunder is destroyed to generate vacancy defects; the dielectric film layer is an undoped insulating dielectric film layer; annealing and mixing; annealing the multi-quantum well structure forming the dielectric film layer to induce the alternately stacked barrier layers and InGaAlAs quantum well layers in the waveguide region to change, thereby forming a quantum well mixed layer region together.

[0007] Optionally, the step of forming the dielectric film layer includes a sputtering deposition process; the material of the dielectric film layer includes SiO2 or SiN x ; The thickness of the dielectric film layer is 50nm~80nm.

[0008] Optionally, the step of forming the isolation protective layer includes: forming an initial isolation protective layer through a first growth process, wherein the initial isolation protective layer covers the entire surface of the multi-quantum well structure; removing the initial isolation protective layer located in the waveguide area through a first etching process to form the isolation protective layer covering the electro-absorption modulation area and the laser light source area, and exposing the waveguide area.

[0009] Optionally, the first growth process includes plasma enhanced chemical vapor deposition or metal organic chemical vapor deposition; the first etching process includes photolithography and / or wet etching and / or dry etching.

[0010] Optionally, the step of providing a multi-quantum well structure includes: providing a laser substrate, which is an N-type InP substrate; forming alternately stacked barrier layers and InGaAlAs quantum well layers on the laser substrate; forming a grating layer 310 and a P-type InP protective layer on the alternately stacked film layers; the grating layer 310 is only located in the laser light source area; the P-type InP protective layer covers the entire surface of the film layer below it and encapsulates the grating layer 310; forming an InGaAs sacrificial layer on the grating layer 310 and the P-type InP protective layer; the isolation protective layer and the dielectric film layer are formed on the InGaAs sacrificial layer.

[0011] Optionally, the method for manufacturing the electro-absorption modulated laser further includes: after the annealing and mixing step, removing the InGaAs sacrificial layer, the isolation protection layer and the dielectric film layer; thereafter, for a device with a ridge waveguide structure, further including: forming a P-type InP covering layer on the grating layer and the P-type InP protection layer; etching the electro-absorption modulation region, the laser light source region and the waveguide region to form a ridge waveguide structure; forming a side protection layer on the side of the ridge waveguide structure; forming an InGaAs contact layer on the surface of the P-type InP covering layer in the electro-absorption modulation region and the laser light source region; evaporating a P-type metal on the surface of the InGaAs contact layer, and evaporating an N-type metal on the surface of the laser substrate. to form an ohmic contact electrode; or, for a device with a buried heterojunction structure, it also includes: etching to form a mesa structure in the electro-absorption modulation region, the laser light source region and the waveguide region; growing a semi-insulating barrier layer and an N-type InP barrier layer on the side of the mesa structure by secondary epitaxial growth; forming a P-type InP covering layer on the surface of the mesa structure, the P-type InP covering layer covering the electro-absorption modulation region and the laser light source region; forming an InGaAs contact layer and an insulating spacer layer on the surface of the P-type InP covering layer in the electro-absorption modulation region and the laser light source region; evaporating a P-type metal on the surface of the InGaAs contact layer, and evaporating an N-type metal on the surface of the laser substrate to form an ohmic contact electrode.

[0012] Optionally, in the annealing mixing step, the annealing temperature is 650° C. to 750° C., and the annealing time is 100 s to 140 s.

[0013] The present invention also provides an electro-absorption modulated laser, which is manufactured using the manufacturing method of the electro-absorption modulated laser provided by the present invention, and comprises: a multi-quantum well structure; the multi-quantum well structure comprises an electro-absorption modulation region, a waveguide region and a laser light source region, wherein the waveguide region is located between the electro-absorption modulation region and the laser light source region; the multi-quantum well structure comprises at least alternately stacked barrier layers and InGaAlAs quantum well layers; and further comprises: a quantum well mixed layer region, wherein the quantum well mixed layer region is located in the waveguide region and is in the same layer as the alternately stacked barrier layers and InGaAlAs quantum well layers.

[0014] Optionally, the multi-quantum well structure includes: a laser substrate, which is an N-type InP substrate; alternately stacked barrier layers and InGaAlAs quantum well layers located on the laser substrate, and a quantum well hybrid layer region on the same layer; a grating layer 310 and a P-type InP protective layer located on the alternately stacked barrier layers and InGaAlAs quantum well layers and the quantum well hybrid layer region; the grating layer 310 is only located in the laser light source area; the P-type InP protective layer covers the entire surface of the film layer below it and encapsulates the grating layer 310.

[0015] Optionally, for a device with a ridge waveguide structure, it further includes: a P-type InP covering layer located on the grating layer 310 and the P-type InP protective layer; the P-type InP covering layer in the electro-absorption modulation area, the laser light source area and the waveguide area constitutes a ridge waveguide structure; a side protection layer located on the side of the ridge waveguide structure; an InGaAs contact layer located on the surface of the P-type InP covering layer in the electro-absorption modulation area and the laser light source area; a P-type metal electrode located on the surface of the InGaAs contact layer; and an N-type metal electrode located on the surface of the laser substrate.

[0016] Alternatively, for a device with a buried heterojunction structure, it also includes: a mesa structure, wherein the mesa structure includes the electro-absorption modulation region, the laser light source region and the laser substrate at a partial height of the waveguide region, alternately stacked barrier layers and InGaAlAs quantum well layers, quantum well mixed layer regions and all of the grating layers 310 and P-type InP protective layers on the laser substrate; a semi-insulating barrier layer and an N-type InP barrier layer located on both sides of the mesa structure; a P-type InP covering layer and an insulating spacer layer located on the surface of the mesa structure; an InGaAs contact layer on the surface of the P-type InP covering layer in the electro-absorption modulation region and the laser light source region; a P-type metal electrode located on the surface of the InGaAs contact layer; and an N-type metal electrode located on the surface of the laser substrate.

[0017] The beneficial effects of the present invention are:

[0018] The manufacturing method of the electro-absorption modulated laser provided by the present invention comprises the following steps: forming an isolation protective layer on the multi-quantum well structure; the isolation protective layer covers the electro-absorption modulation area and the laser light source area, and exposes the waveguide area; forming a dielectric film layer; the dielectric film layer covers the electro-absorption modulation area, the laser light source area and the waveguide area; during the formation process, the interface between the dielectric film layer in the waveguide area and the film layer below it is destroyed to produce vacancy defects; the dielectric film layer is an undoped insulating dielectric film layer, and the interface between the dielectric film layer and the film layer below it is destroyed to produce vacancy defects when the dielectric film layer is formed in the multi-quantum well structure in the waveguide area, while other areas are covered by the isolation protective layer to keep the interface intact. During the subsequent annealing process, the vacancy defects in the waveguide area will quickly diffuse into the quantum wells in this area (i.e., the alternately stacked barrier layers and InGaAlAs quantum well layers), causing the mixing of well atoms and barrier atoms in the quantum wells, thereby causing changes in the composition of the quantum well materials. Unlike other quantum well intermixing methods such as ion implantation and impurity diffusion, the impurity-free and hole-free enhanced disordering process used in the present invention does not cause electrical and optical losses in the device, because there is no impurity intervention in the entire process, only the disorder of the lattice structure of the quantum well has changed. At the same time, in the present invention, only the very small area of ​​the waveguide area has completed the quantum well intermixing, and the remaining areas including the laser light source area and the electro-absorption modulation area are under the protection of the isolation protection layer. Neither the quantum well structure nor the performance will be affected, the crystal quality will not decrease, and there will be no problem of residual defects. The stability of the device is guaranteed to the greatest extent.

[0019] The electro-absorption modulated laser provided by the present invention is manufactured using the manufacturing method of the electro-absorption modulated laser provided by the present invention. During the formation process, the interface between the dielectric film layer located in the waveguide region and the film layer below it is destroyed to produce vacancy defects; the dielectric film layer is an undoped insulating dielectric film layer, and the interface between the dielectric film layer and the film layer below it in the waveguide region is destroyed to produce vacancy defects when the dielectric film layer is formed, while other regions are covered by an isolation protective layer to keep the interface intact. During the subsequent annealing process, the vacancy defects in the waveguide region will quickly diffuse into the quantum wells in this region (i.e., the alternately stacked barrier layers and InGaAlAs quantum well layers), causing the mixing of well atoms and barrier atoms in the quantum wells, thereby causing changes in the composition of the quantum well material. Unlike other quantum well intermixing methods such as ion implantation and impurity diffusion, the impurity-free and hole-free enhanced disordering process used in the present invention does not cause electrical and optical losses of the device, because there is no impurity intervention in the entire process, only the disorder of the lattice structure of the quantum well changes. At the same time, in the present invention, only the waveguide area, which is a very small area, completes the quantum well intermixing, and the rest of the area, including the laser light source area and the electro-absorption modulation area, is protected by the isolation protection layer, so that neither the quantum well structure nor the performance will be affected, the crystal quality will not be reduced, and there will be no residual defects, which greatly guarantees the stability of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 A schematic diagram of a process for manufacturing an electro-absorption modulated laser of the present invention;

[0022] Figure 2 A schematic diagram of forming an InGaAs sacrificial layer on the grating layer and the P-type InP protective layer in a method for manufacturing an electro-absorption modulated laser according to an embodiment of the present invention;

[0023] Figure 3 A schematic diagram of forming an isolation protection layer in a method for manufacturing an electro-absorption modulated laser according to an embodiment of the present invention;

[0024] Figure 4 It is a schematic diagram of forming a dielectric film layer in a method for manufacturing an electro-absorption modulated laser according to an embodiment of the present invention;

[0025] Figure 5A schematic diagram of forming a quantum well intermixed layer region in a method for manufacturing an electro-absorption modulated laser according to an embodiment of the present invention;

[0026] Figure 6 It is a schematic diagram of forming a P-type InP capping layer after forming a quantum well mixed layer region in a method for manufacturing an electro-absorption modulated laser according to an embodiment of the present invention;

[0027] Figure 7 It is a schematic diagram of forming an InGaAs contact layer after forming a quantum well mixed layer region in a method for manufacturing an electro-absorption modulated laser according to an embodiment of the present invention;

[0028] Figure 8 It is a cross-sectional schematic diagram of a ridge waveguide structure device formed after forming a quantum well hybrid layer in a method for manufacturing an electro-absorption modulated laser according to an embodiment of the present invention;

[0029] Fig. 9 It is a cross-sectional schematic diagram of a buried heterojunction structure device formed after forming a quantum well hybrid layer in a method for manufacturing an electro-absorption modulated laser according to an embodiment of the present invention. DETAILED DESCRIPTION

[0030] In order to solve the problems of crystal quality degradation and residual defects damaging the epitaxial layer caused by long-term high-temperature annealing when manufacturing InGaAlAs-based electro-absorption modulated lasers by quantum well hybridization in the prior art, the present invention provides a method for manufacturing an electro-absorption modulated laser and an electro-absorption modulated laser.

[0031] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. In the description of the present invention, it should be noted that the terms "first", "second" and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0032] Example 1

[0033] refer to Figure 1 ,as well as Figure 2~Figure 5 This embodiment provides a method for manufacturing an electro-absorption modulated laser, comprising the following steps:

[0034] A multi-quantum well structure is provided; the multi-quantum well structure comprises an electro-absorption modulation region A, a waveguide region B and a laser light source region C, wherein the waveguide region is located between the electro-absorption modulation region A and the laser light source region C; the multi-quantum well structure comprises at least alternately stacked barrier layers and InGaAlAs quantum well layers 200;

[0035] An isolation protection layer 500 is formed on the multi-quantum well structure; the isolation protection layer 500 covers the electro-absorption modulation area A and the laser light source area C, and exposes the waveguide area B;

[0036] A dielectric film layer 600 is formed; the dielectric film layer 600 covers the isolation protection layer 500 of the electric absorption modulation area A and the laser light source area C, and the waveguide area B; during the formation of the dielectric film layer 600, the interface between the dielectric film layer 600 located in the waveguide area B and the film layer thereunder is destroyed to generate vacancy defects; the dielectric film layer 600 is an undoped insulating dielectric film layer;

[0037] Annealing and mixing; the multi-quantum well structure forming the dielectric film layer 600 is annealed to induce changes in the alternately stacked barrier layers and InGaAlAs quantum well layers 200 of the waveguide region B to form a quantum well mixed layer region 210 together.

[0038] It should be noted that 200 in the figure refers to the overall structure of alternately stacked barrier layers and InGaAlAs quantum well layers, rather than just the InGaAlAs quantum well layers.

[0039] The manufacturing method of the electro-absorption modulated laser provided in this embodiment is as follows: an isolation protection layer 500 is formed on the multi-quantum well structure; the isolation protection layer 500 covers the electro-absorption modulation area A and the laser light source area C, and exposes the waveguide area B; a dielectric film layer 600 is formed; the dielectric film layer 600 covers the electro-absorption modulation area A, the laser light source area C and the waveguide area B; during the formation process, the interface between the dielectric film layer 600 located in the waveguide area B and the film layer thereunder is destroyed to produce vacancy defects; the dielectric film layer 600 is an undoped insulating dielectric film layer, and when the dielectric film layer 600 is formed, the interface between the dielectric film layer 600 and the film layer thereunder in the exposed waveguide area B is destroyed to produce vacancy defects, while other areas are covered by the isolation protection layer 500 to keep the interface intact. During the subsequent annealing process, the vacancy defects in the waveguide region B will quickly diffuse into the quantum wells in this region (i.e., the alternately stacked barrier layers and InGaAlAs quantum well layers 200), causing the mixing of well atoms and barrier atoms in the quantum wells, thereby causing changes in the composition of the quantum well materials. Unlike other quantum well intermixing methods such as ion implantation and impurity diffusion, the impurity-free and hole-free enhanced disordering process used in the present invention does not cause electrical and optical losses in the device, because there is no impurity intervention in the entire process, only the disorder of the lattice structure of the quantum well has changed. At the same time, in the present invention, only the extremely small area of ​​the waveguide region B completes the quantum well intermixing, and the remaining areas including the laser light source region C and the electro-absorption modulation region A are under the protection of the isolation protection layer 500, and neither the quantum well structure nor the performance will be affected, the crystal quality will not decrease, and there will be no problem of residual defects. The stability of the device is greatly guaranteed.

[0040] For further reference, Figure 2 , the step of providing a multi-quantum well structure comprises:

[0041] Providing a laser substrate 100, wherein the laser substrate 100 is an N-type InP substrate;

[0042] Forming alternately stacked barrier layers and InGaAlAs quantum well layers 200 on the laser substrate 100; forming a grating layer 310 and a P-type InP protective layer 320 on the alternately stacked film layers;

[0043] The grating layer 310 is only located in the laser light source area;

[0044] The P-type InP protective layer 320 covers the entire surface of the film layer below it and encapsulates the grating layer 310;

[0045] forming an InGaAs sacrificial layer on the grating layer 310 and the P-type InP protective layer 320;

[0046] The isolation protection layer 500 and the dielectric film layer 600 are formed on the InGaAs sacrificial layer.

[0047] The above-mentioned film layers can be formed by epitaxial growth through a process such as metal organic chemical vapor deposition.

[0048] The thickness of the sacrificial layer is about 200nm~500nm, for example, it can be 200nm, 300nm, 400nm, 500nm. If the sacrificial layer is too thin, less than 200nm, it cannot form perfect coverage and cannot effectively protect the multi-quantum well structure underneath; if the sacrificial layer is too thick, greater than 500nm, it will increase the temperature and time required for quantum well intermixing. Therefore, the sacrificial layer thickness is within the range of 200nm~500nm, which can strike a balance between effectively protecting the multi-quantum well structure and minimizing the intermixing temperature and time.

[0049] For further reference, Figure 3 , forming an isolation protection layer 500, covering the electro-absorption modulation area A and the laser light source area C, exposing the waveguide area B. The step of forming the isolation protection layer 500 includes: forming an initial isolation protection layer through a first growth process, the initial isolation protection layer covering the entire surface of the multi-quantum well structure; removing the initial isolation protection layer located in the waveguide area B through a first etching process, forming the isolation protection layer 500 covering the electro-absorption modulation area A and the laser light source area C, and exposing the waveguide area B. In this way, during the formation of the dielectric film layer 600, the electro-absorption modulation area A and the laser light source area C can be protected from forming a damaged interface and vacancy defects. In the subsequent annealing process, there will be no defect diffusion, the crystal quality of the quantum well layer below will not be affected, and there will be no problem of residual defects.

[0050] Specifically, in this embodiment, the first growth process includes plasma enhanced chemical vapor deposition or metal organic chemical vapor deposition; the first etching process includes photolithography and / or wet etching and / or dry etching. In addition, it also includes pre-processing and post-processing steps such as cleaning, purging, and drying, and those skilled in the art can select according to actual needs.

[0051] For further reference, Figure 4 , forming a dielectric film layer 600, the dielectric film layer 600 covers the isolation protection layer 500 of the electro-absorption modulation area A and the laser light source area C, and the surface of the multi-quantum well structure exposed in the waveguide area B (i.e., the surface of the InGaAs sacrificial layer); the step of forming the dielectric film layer 600 includes a sputtering deposition process; the material of the dielectric film layer 600 includes SiO2 or SiN x; The thickness of the dielectric film layer 600 is 50nm~80nm, for example, it can be 50nm, 60nm, 70nm, 80nm. Due to the use of the sputtering deposition process, the dielectric film layer 600 formed by deposition causes the interface between the multi-quantum well structure surface exposed in the waveguide region B and the dielectric film layer 600 to be destroyed during the formation process, thereby forming vacancy defects. If the film thickness is less than 50nm, the dielectric film layer 600 is too thin and a uniform and stable coating layer cannot be formed; if it is greater than 80nm, the dielectric film layer 600 is too thick, which is not conducive to the removal of the dielectric film after the subsequent annealing is completed. Further, refer to Figure 5 . In the annealing step, the stacked alternating quantum well layers and barrier layers located below the dielectric film layer 600 in the waveguide region B are rearranged under the annealing conditions due to the diffusion lattice of defects to form a quantum well hybrid layer region 210. Wherein, different functional layers are formed according to different doping concentrations, including at least a confinement layer (SCH) and a buffer layer. In the annealing hybrid step, the annealing temperature is 650°C to 750°C, for example, it can be 650°C, 680°C, 700°C, 720°C, 750°C; the annealing time is 100s, 120s, 140s. If the annealing temperature is too high or the annealing time is too long, it is easy to cause excessive blue shift and degradation of material properties; if the annealing temperature is too low or the annealing time is too short, the wavelength blue shift is insufficient and cannot meet the performance requirements of the device. In a preferred embodiment, the annealing temperature is 700°C and the annealing time is 120s, which can induce a blue shift of about 20nm, meeting the working requirements of most electro-absorption modulators.

[0052] For further reference, Figure 6 The method for manufacturing the electro-absorption modulated laser provided in this embodiment further includes: after the annealing and mixing step, removing the InGaAs sacrificial layer, the isolation protection layer 500 and the dielectric film layer 600; thereafter,

[0053] refer to Figure 7 and Figure 8 , for devices with ridge waveguide structures, it also includes:

[0054] Forming a P-type InP capping layer 700 on the grating layer 310 and the P-type InP protective layer 320;

[0055] A ridge waveguide structure is formed by etching the electro-absorption modulation area A, the laser light source area C and the waveguide area B;

[0056] Forming a side protection layer 710 on the side of the ridge waveguide structure;

[0057] An InGaAs contact layer 800 is formed on the surface of the P-type InP cover layer 700 in the electro-absorption modulation region A and the laser light source region C;

[0058] P-type metal is evaporated on the surface of the InGaAs contact layer 800 to form a P-type metal electrode 910, and N-type metal is evaporated on the surface of the laser substrate 100 to form an N-type metal electrode 920. The P-type metal electrode 910 and the N-type metal electrode 920 are the ohmic contact electrodes.

[0059] Alternatively, refer to Figure 7 and Fig. 9 , for buried heterojunction devices, also includes:

[0060] A mesa structure is formed by etching the electro-absorption modulation area A, the laser light source area C and the waveguide area B;

[0061] A semi-insulating barrier layer 620 and an N-type InP barrier layer 630 are grown on the side of the mesa structure by secondary epitaxial growth;

[0062] A P-type InP covering layer 700 is formed on the surface of the mesa structure, and the P-type InP covering layer 700 covers the electro-absorption modulation area A and the laser light source area C;

[0063] An InGaAs contact layer 800 and an insulating spacer layer 810 are formed on the surface of the P-type InP cover layer 700 in the electro-absorption modulation area A and the laser light source area C;

[0064] P-type metal is evaporated on the surface of the InGaAs contact layer 800 to form a P-type metal electrode 910, and N-type metal is evaporated on the surface of the laser substrate 100 to form an N-type metal electrode 920. The P-type metal electrode 910 and the N-type metal electrode 920 are the ohmic contact electrodes.

[0065] Example 2

[0066] This embodiment provides an electro-absorption modulated laser, which is manufactured using the manufacturing method of the electro-absorption modulated laser provided in the above embodiment 1. Figure 5 ,include:

[0067] A multi-quantum well structure; the multi-quantum well structure comprises an electro-absorption modulation region A, a waveguide region B and a laser light source region C, wherein the waveguide region B is located between the electro-absorption modulation region A and the laser light source region C; the multi-quantum well structure comprises at least alternately stacked barrier layers and InGaAlAs quantum well layers 200;

[0068] It also includes: a quantum well hybrid layer region 210 , which is located in the waveguide region B and is in the same layer as the alternately stacked barrier layers and InGaAlAs quantum well layers 200 .

[0069] The electro-absorption modulated laser provided in this embodiment is manufactured using the manufacturing method of the electro-absorption modulated laser provided in the above-mentioned embodiment 1. During the formation process, the interface between the dielectric film layer 600 located in the waveguide region B and the film layer thereunder is destroyed to produce vacancy defects; the dielectric film layer 600 is an undoped insulating dielectric film layer 600, and the interface between the dielectric film layer 600 and the film layer thereunder in the multi-quantum well structure of the waveguide region B is destroyed to produce vacancy defects when the dielectric film layer 600 is formed, while other regions are covered by the isolation protection layer 500 to keep the interface intact. During the subsequent annealing process, the vacancy defects in the waveguide region B will quickly diffuse into the quantum wells in this region (i.e., the alternately stacked barrier layers and the InGaAlAs quantum well layers 200), causing the mixing of the well atoms and barrier atoms in the quantum wells, thereby causing changes in the composition of the quantum well materials. Unlike other quantum well intermixing methods such as ion implantation and impurity diffusion, the impurity-free and hole-free enhanced disordering process used in the present invention does not cause electrical and optical losses in the device, because there is no impurity intervention in the entire process, only the disorder of the lattice structure of the quantum well has changed. At the same time, in the present invention, only the very small area of ​​the waveguide area B has completed the quantum well intermixing, and the remaining areas including the laser light source area C and the electro-absorption modulation area A are under the protection of the isolation protection layer 500. Neither the quantum well structure nor the performance will be affected, the crystal quality will not decrease, and there will be no problem of residual defects. The stability of the device is guaranteed to the greatest extent.

[0070] For further information, please refer to Figure 5 , the multi-quantum well structure comprises:

[0071] A laser substrate 100, wherein the laser substrate 100 is an N-type InP substrate;

[0072] The alternately stacked barrier layers and InGaAlAs quantum well layers 200 and the quantum well hybrid layer region 210 on the same layer are located on the laser substrate 100;

[0073] A grating layer 310 and a P-type InP protective layer 320 located on the alternately stacked barrier layers and InGaAlAs quantum well layers 200 and the quantum well mixed layer region 210;

[0074] The grating layer 310 is only located in the laser light source area; the P-type InP protection layer 320 covers the entire surface of the film layer below it and encapsulates the grating layer 310 .

[0075] refer to Figure 7 and Figure 8 , for devices with ridge waveguide structures, it also includes:

[0076] A P-type InP capping layer 700 located on the grating layer 310 and the P-type InP protective layer 320;

[0077] The P-type InP cover layer 700 of the electro-absorption modulation area A, the laser light source area C and the waveguide area B constitute a ridge waveguide structure;

[0078] A side protection layer 710 located at the side of the ridge waveguide structure;

[0079] An InGaAs contact layer 800 located on the surface of the P-type InP cover layer 700 in the electro-absorption modulation region A and the laser light source region C;

[0080] A P-type metal electrode 910 located on the surface of the InGaAs contact layer 800;

[0081] An N-type metal electrode 920 located on the surface of the laser substrate 100;

[0082] Alternatively, refer to Figure 7 and Fig. 9 , for buried heterojunction devices, also includes:

[0083] A mesa structure, the mesa structure includes the laser substrate 100 of a part of the height of the electro-absorption modulation region A, the laser light source region C and the waveguide region B, the alternately stacked barrier layers and InGaAlAs quantum well layers 200 on the laser substrate 100, the quantum well mixed layer region 210, and all of the grating layer 310 and the P-type InP protective layer 320;

[0084] A semi-insulating barrier layer 620 and an N-type InP barrier layer 630 located on both sides of the mesa structure;

[0085] A P-type InP capping layer 700 located on the surface of the mesa structure;

[0086] The InGaAs contact layer 800 and the insulating spacer layer 810 on the surface of the P-type InP cover layer 700 of the electro-absorption modulation region A and the laser light source region C;

[0087] A P-type metal electrode 910 located on the surface of the InGaAs contact layer 800;

[0088] An N-type metal electrode 920 is located on the surface of the laser substrate 100 .

[0089] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A method for manufacturing an electro-absorption modulated laser, characterized in that: The following steps are involved: A multi-quantum well structure is provided; the multi-quantum well structure comprises an electro-absorption modulation region, a waveguide region and a laser light source region, wherein the waveguide region is located between the electro-absorption modulation region and the laser light source region; the multi-quantum well structure comprises at least alternately stacked barrier layers and InGaAlAs quantum well layers; forming an isolation protection layer on the multi-quantum well structure; the isolation protection layer covers the electro-absorption modulation area and the laser light source area, and exposes the waveguide area; A dielectric film layer is formed; the dielectric film layer covers the isolation protection layer of the electric absorption modulation area and the laser light source area, and the waveguide area; during the formation of the dielectric film layer, the interface between the dielectric film layer in the waveguide area and the film layer thereunder is destroyed to generate vacancy defects; the dielectric film layer is an undoped insulating dielectric film layer; Annealing and mixing; annealing the multi-quantum well structure forming the dielectric film layer to induce changes in the alternately stacked barrier layers and InGaAlAs quantum well layers in the waveguide region to jointly form a quantum well mixed layer region.

2. The method for manufacturing an electro-absorption modulated laser according to claim 1, characterized in that: The step of forming the dielectric film layer includes a sputtering deposition process; The material of the dielectric film layer includes SiO2 or SiN x ; The thickness of the dielectric film layer is 50nm-80nm.

3. The method for manufacturing an electro-absorption modulated laser according to claim 1, characterized in that: The step of forming the isolation protection layer includes: Forming an initial isolation protection layer through a first growth process, wherein the initial isolation protection layer covers the entire surface of the multi-quantum well structure; The initial isolation protection layer located in the waveguide region is removed through a first etching process to form an isolation protection layer covering the electro-absorption modulation region and the laser light source region and exposing the waveguide region.

4. The method for manufacturing an electro-absorption modulated laser according to claim 3, characterized in that: The first growth process includes plasma enhanced chemical vapor deposition or metal organic chemical vapor deposition; The first etching process includes photolithography and / or wet etching and / or dry etching.

5. The method for manufacturing an electro-absorption modulated laser according to claim 1, characterized in that: The steps of providing a multi-quantum well structure include: Providing a laser substrate, wherein the laser substrate is an N-type InP substrate; forming alternately stacked barrier layers and InGaAlAs quantum well layers on the laser substrate; A grating layer and a P-type InP protective layer are formed on the alternately stacked film layers; the grating layer is only located in the laser light source area; the P-type InP protective layer covers the entire surface of the film layer below it and encapsulates the grating layer; forming an InGaAs sacrificial layer on the grating layer and the P-type InP protective layer; The isolation protection layer and the dielectric film layer are formed on the InGaAs sacrificial layer.

6. The method for manufacturing an electro-absorption modulated laser according to claim 5, characterized in that: Also includes: After the annealing and mixing step, removing the InGaAs sacrificial layer, the isolation protection layer and the dielectric film layer; After that, for ridge waveguide structure devices, it also includes: forming a P-type InP capping layer on the grating layer and the P-type InP protective layer; Etching to form a ridge waveguide structure in the electro-absorption modulation area, the laser light source area and the waveguide area; forming a side protection layer on the side of the ridge waveguide structure; Forming an InGaAs contact layer on the surface of the P-type InP cover layer in the electro-absorption modulation region and the laser light source region; Vapor-depositing a P-type metal on the surface of the InGaAs contact layer and vapor-depositing an N-type metal on the surface of the laser substrate to form an ohmic contact electrode; Alternatively, for a buried heterojunction device, the invention further comprises: Etching to form a mesa structure in the electro-absorption modulation area, the laser light source area and the waveguide area; Growing a semi-insulating barrier layer and an N-type InP barrier layer on the side of the mesa structure by secondary epitaxial growth; Forming a P-type InP covering layer on the surface of the mesa structure, wherein the P-type InP covering layer covers the electro-absorption modulation region and the laser light source region; Forming an InGaAs contact layer and an insulating spacer layer on the surface of the P-type InP cover layer in the electro-absorption modulation region and the laser light source region; P-type metal is evaporated on the surface of the InGaAs contact layer and the insulating spacer layer, and N-type metal is evaporated on the surface of the laser substrate to form an ohmic contact electrode.

7. The method for manufacturing an electro-absorption modulated laser according to claim 1, characterized in that: In the annealing mixing step, the annealing temperature is 650° C. to 750° C., and the annealing time is 100 s to 140 s.

8. An electro-absorption modulated laser, characterized in that: The method for manufacturing an electro-absorption modulated laser according to claim 1 comprises: A multi-quantum well structure; the multi-quantum well structure comprises an electro-absorption modulation region, a waveguide region and a laser light source region, wherein the waveguide region is located between the electro-absorption modulation region and the laser light source region; The multi-quantum well structure comprises at least alternately stacked barrier layers and InGaAlAs quantum well layers; It also includes: a quantum well hybrid layer region, which is located in the waveguide region and is in the same layer as the alternately stacked barrier layers and InGaAlAs quantum well layers.

9. The electro-absorption modulated laser according to claim 8, characterized in that: The multi-quantum well structure comprises: A laser substrate, wherein the laser substrate is an N-type InP substrate; Alternatingly stacked barrier layers and InGaAlAs quantum well layers located on the laser substrate, and a quantum well hybrid layer region on the same layer; A grating layer and a P-type InP protective layer are located on the alternately stacked barrier layers and InGaAlAs quantum well layers and the quantum well mixed layer region; the grating layer is only located in the laser light source region; the P-type InP protective layer covers the entire surface of the film layer below it and encapsulates the grating layer.

10. The electro-absorption modulated laser according to claim 9, characterized in that: For devices with ridge waveguide structures, it also includes: A P-type InP capping layer located on the grating layer and the P-type InP protective layer; The electro-absorption modulation region, the laser light source region and the P-type InP covering layer in the waveguide region form a ridge waveguide structure; A side protection layer located at a side of the ridge waveguide structure; An InGaAs contact layer located on the surface of the P-type InP cover layer in the electro-absorption modulation region and the laser light source region; A P-type metal electrode located on the surface of the InGaAs contact layer; An N-type metal electrode located on the surface of the laser substrate; Alternatively, for a buried heterojunction device, the invention further comprises: A mesa structure, comprising the electro-absorption modulation region, the laser light source region and the laser substrate at a partial height of the waveguide region, alternately stacked barrier layers and InGaAlAs quantum well layers on the laser substrate, a quantum well hybrid layer region, and all of the grating layers and a P-type InP protective layer; A semi-insulating barrier layer and an N-type InP barrier layer located on both sides of the mesa structure; A P-type InP capping layer located on the surface of the mesa structure; InGaAs contact layer and insulating spacer layer on the surface of the P-type InP cover layer in the electro-absorption modulation region and the laser light source region; A P-type metal electrode located on the surface of the InGaAs contact layer; An N-type metal electrode is located on the surface of the laser substrate.

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