InP laser structure and manufacturing method thereof

Abstract

The invention provides an InP laser structure and a manufacturing method thereof, and the method comprises the steps: forming an electrode opening in a passivation layer, carrying out Si ion implantation to form a doping compensation layer with the thickness smaller than that of a contact layer in the contact layer at the electrode opening, and then forming a P-surface metal electrode filled in the electrode opening, and local laser thermal annealing is carried out at the interface of the P-surface metal electrode and the contact layer so as to form a gold silicide layer at the interface. On one hand, Si ion implantation can reduce the surface carrier concentration of the uppermost layer of the device and reduce the Schottky barrier so as to obtain smaller contact resistance, on the other hand, the Si ion implantation can react with Au ions diffused to the surface of the contact layer in the subsequent laser annealing process to generate a gold silicide layer so as to further reduce the contact resistance, and meanwhile, the device performance is improved. By controlling the size of the laser beam spot, the influence on the active area can be reduced, and the product performance is improved. The InP laser structure provided by the invention has lower contact resistance and higher active area quality.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductors and relates to an InP laser structure and a manufacturing method thereof. Background Art

[0002] Indium Phosphide (InP) lasers, based on III-V compound semiconductor materials, are widely used in fiber optic communications, optical sensing, and other fields due to their efficient output in the long-wavelength (1.3-1.6μm) band. The core principle of InP lasers is stimulated emission amplification, which requires three key conditions: population inversion, resonant cavity feedback, and gain greater than loss.

[0003] The core materials of InP lasers are InP (indium phosphide) and related alloys (such as InGaAsP). Their energy band structure is that of a direct bandgap semiconductor (the bottom of the conduction band and the top of the valence band are at the same wave vector), and photons can be directly released when electrons and holes recombine. When a forward bias is applied to both ends of the laser, electrons are injected from the n-type region (such as n-InP) into the conduction band, and holes are injected from the p-type region (such as p-InP) into the valence band, eventually accumulating in the active region (such as the InGaAsP quantum well). The active region is the core area for carrier recombination (the bandgap width of the material is smaller than the confinement layers on both sides). When the injected carrier concentration is high enough, the number of electrons in the conduction band exceeds the number of holes in the valence band (or the number of high-energy-level particles exceeds the number of low-energy levels), forming a "population inversion" (the prerequisite for stimulated emission). At this time, when electrons transition from the conduction band to the valence band, they release photons with energy matching the bandgap width. The cleavage surfaces (or coated mirrors) at both ends of the laser form a resonant cavity. When photons reflect back and forth in the cavity, they will continue to interact with the particles in the active area, triggering "stimulated radiation" (photon-induced electron-hole recombination, generating new photons with the same frequency, phase, and direction as the incident photons), thereby amplifying the optical signal. When the gain of the optical amplification (provided by the active area) is greater than the loss in the cavity (such as reflection loss and material absorption), the "threshold condition" is met, and the optical signal forms a stable oscillation in the resonant cavity, eventually outputting coherent laser light from one end (or both ends). The output wavelength of the InP laser is determined by the bandgap width of the active area material.

[0004] InP lasers usually include substrate, buffer layer, lower confinement layer, active region, upper confinement layer, waveguide layer, contact layer and electrode layer (upper electrode, lower electrode). The contact layer usually uses P-type InGaAs. Since high doping concentration will reduce the quality of the contact layer material, the doping concentration of the contact layer usually does not exceed 1E19 / cm 3 , resulting in a high contact resistance (20–100Ω·cm 2To obtain good ohmic contact, the product usually needs to be annealed, and the annealing requires a relatively high temperature (annealing temperature > 450°C) for activation. Conventional annealing processes have the risk of damaging the active area because the contact layer is close to the active area (<5μm).

[0005] Therefore, how to improve the manufacturing process of InP laser electrodes to reduce contact resistance while retaining electrode adhesion, reduce the impact on the active area, improve product performance, and achieve simple process and controllable cost has become an important technical problem that needs to be solved urgently by technical personnel in this field.

[0006] It should be noted that the above introduction to the technical background is merely intended to provide a clear and complete description of the technical solutions of this application and facilitate understanding by those skilled in the art. Simply because these solutions are described in the background technology section of this application, it should not be assumed that the above technical solutions are well known to those skilled in the art. Summary of the Invention

[0007] In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide an InP laser structure and a manufacturing method thereof, which are used to solve the problem that the contact resistance between the electrode and the contact layer in the existing InP laser is high and the active area is easily damaged during the manufacturing process.

[0008] To achieve the above-mentioned and other related purposes, the present invention provides a method for manufacturing an InP laser structure, comprising the following steps:

[0009] A semiconductor structure is provided, comprising an InP substrate, an active layer, a waveguide layer, and a contact layer arranged in sequence from bottom to top, wherein the waveguide layer comprises a ridge waveguide, and the contact layer comprises a P-type InGaAs layer;

[0010] forming a passivation layer on the surface of the semiconductor structure, and forming an electrode opening in the passivation layer above the ridge waveguide;

[0011] Performing Si ion implantation to form a doped compensation layer in the contact layer at the electrode opening, wherein the thickness of the doped compensation layer is smaller than the thickness of the contact layer;

[0012] forming a P-side metal electrode filled in the electrode opening, wherein the P-side metal electrode comprises an Au layer;

[0013] A laser annealing process is used to perform local thermal annealing at the interface between the P-side metal electrode and the contact layer to form a gold silicide layer at the interface.

[0014] Optionally, the doping concentration range of the P-type InGaAs layer is 1E17-1E19 cm -3The dose range of Si ion implantation is 1E15~9E15 cm -2 The energy range of the Si ion implantation is 2 to 10 keV.

[0015] Optionally, the plane where the peak concentration of the Si ion implantation is located is located below the interface between the P-side metal electrode and the contact layer and the distance between the plane and the interface is in the range of 5 to 10 nm, and the thickness of the doping compensation layer is in the range of 5 to 10 nm.

[0016] Optionally, the P-side metal electrode further includes a Ti layer, the Au layer is located above the Ti layer, and the thickness of the Ti layer is less than 10 nm.

[0017] Optionally, the thickness of the Au layer is in the range of 50 to 150 nm.

[0018] Optionally, the laser beam spot area used in the laser annealing process is no greater than 120% of the electrode region area.

[0019] Optionally, the laser beam spot diameter used in the laser annealing process is less than 5 microns.

[0020] Optionally, the laser annealing process uses a laser wavelength range of 510-550 nm and an energy density range of 1-5 J / cm 2 .

[0021] Optionally, the laser annealing process uses a single pulse to complete annealing, and the pulse width range is 2 to 8 ms.

[0022] The present invention also provides an InP laser structure, comprising:

[0023] An InP substrate, an active layer, a waveguide layer, and a contact layer are sequentially arranged from bottom to top, wherein the waveguide layer includes a ridge waveguide, and the contact layer includes a P-type InGaAs layer;

[0024] A P-surface metal electrode is located above the ridge waveguide and on the surface of the contact layer, wherein the P-surface metal electrode comprises an Au layer;

[0025] A gold silicide layer is located at the interface between the P-side metal electrode and the contact layer.

[0026] As described above, the method for manufacturing an InP laser structure of the present invention comprises: after forming an electrode opening in the passivation layer, performing Si ion implantation to form a doped compensation layer in the contact layer at the electrode opening; the doped compensation layer is thinner than the contact layer; then forming a P-side metal electrode including an Au layer filled in the electrode opening; and then performing local thermal annealing at the interface between the P-side metal electrode and the contact layer using a laser annealing process to form a gold silicide layer at the interface. The present invention, by implanting a certain dose of Si ions into the P-type InGaAs layer, can reduce the surface carrier concentration of the topmost layer of the device, thereby lowering the Schottky barrier and thus obtaining a lower contact resistance; and, during the subsequent laser annealing process, the injected Si ions react with the Au ions diffused to the surface of the contact layer to form a gold silicide layer, which can further reduce the contact resistance. At the same time, by controlling the laser beam spot size during the laser annealing process, the impact on the active area can be reduced, thereby improving product performance. The InP laser structure of the present invention has a gold silicide layer at the interface between the P-face metal electrode and the contact layer, has lower contact resistance, and has a higher quality active region and good device performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The diagram shows a structure obtained after performing an epitaxial doping process and a metal deposition process in a manufacturing method.

[0028] Figure 2 Shown as Figure 1 Schematic diagram of annealing of the structure shown.

[0029] Figure 3 Shown is a process flow chart of the method for manufacturing the InP laser structure of the present invention.

[0030] Figure 4 A schematic diagram showing a semiconductor structure provided for the method of fabricating an InP laser structure of the present invention.

[0031] Figure 5 It is a schematic diagram showing the structure obtained after forming electrode openings in the passivation layer according to the method for manufacturing the InP laser structure of the present invention.

[0032] Figure 6 It is a schematic diagram showing the method for manufacturing an InP laser structure of the present invention, wherein Si ions are implanted into a structure having an electrode opening.

[0033] Figure 7 It is a schematic diagram showing the structure obtained after forming a P-side metal electrode filled in the electrode opening according to the method for manufacturing the InP laser structure of the present invention.

[0034] Figure 8It is a schematic diagram showing the method for manufacturing the InP laser structure of the present invention, wherein a laser annealing process is used to perform local thermal annealing at the interface between the P-side metal electrode and the contact layer.

[0035] Figure 9 It is a schematic diagram showing the structure obtained after laser local thermal annealing according to the method for manufacturing the InP laser structure of the present invention.

[0036] Description of Reference Numerals

[0037] 101 InP substrate

[0038] 102 active layer

[0039] 103 waveguide layer

[0040] 104 contact layer

[0041] 105 passivation layer

[0042] 106 Metal Layer

[0043] Steps S1 to S5

[0044] 201 InP substrate

[0045] 202 active layer

[0046] 203 waveguide layer

[0047] 203a Ridge waveguide

[0048] 203b Groove

[0049] 204 contact layer

[0050] 205 passivation layer

[0051] 206 electrode opening

[0052] 207 Doped Compensation Layer

[0053] 208 P surface metal electrode

[0054] 209 Laser beam spot

[0055] 210 Gold Silicide Layer DETAILED DESCRIPTION

[0056] See also Figure 1 and Figure 2 ,in, Figure 1 The schematic diagram shows a structure obtained after epitaxial doping and metal deposition processes in a manufacturing method, including an InP substrate 101, an active layer 102, a waveguide layer 103, a contact layer 104, a passivation layer 105, and a metal layer 106. Figure 2 Shown as Figure 1 The schematic diagram of the structure shown in the figure shows annealing, where double-sided heating is used at a temperature of 460°. Due to the high annealing temperature and the close proximity to the active area (<5μm), there is a risk of damaging the active area. The present invention provides a simple and cost-effective method for fabricating an InP laser structure. This method can reduce the contact resistance between the electrode and the contact layer and minimize the impact of electrode fabrication on the active area, thereby helping to improve product performance.

[0057] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention.

[0058] It should be emphasized that the term "include / comprising" when used herein refers to the presence of features, integers, steps or components, but does not exclude the presence or addition of one or more other features, integers, steps or components.

[0059] Features described and / or illustrated with respect to one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments.

[0060] For example, when describing the embodiments of the present invention, schematic diagrams illustrating device structures may be partially enlarged for ease of explanation. These schematic diagrams are merely illustrative and should not limit the scope of the present invention. Furthermore, in actual production, three-dimensional dimensions, including length, width, and depth, should be included.

[0061] For convenience, spatially relative terms such as "under," "below," "below," "below," "above," and "on" may be used herein to describe the relationship of one element or feature to other elements or features shown in the drawings. It will be understood that these spatially relative terms are intended to encompass orientations of the device in use or operation in addition to the orientation depicted in the drawings. Additionally, when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present.

[0062] In the context of the present application, a structure described as a first feature being "above" a second feature may include embodiments where the first and second features are in direct contact, and may also include embodiments where additional features are formed between the first and second features, such that the first and second features may not be in direct contact.

[0063] It should be noted that the illustrations provided in this embodiment are only used to schematically illustrate the basic concept of the present invention. Therefore, the illustrations only show components related to the present invention and are not drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component can be changed at will, and the component layout type may also be more complicated.

[0064] The present invention provides a method for manufacturing an InP laser structure. Figure 3 , shown as a process flow diagram of the method, comprising the following steps:

[0065] S1: providing a semiconductor structure, the semiconductor structure comprising an InP substrate, an active layer, a waveguide layer, and a contact layer arranged in sequence from bottom to top, the waveguide layer comprising a ridge waveguide, and the contact layer comprising a P-type InGaAs layer;

[0066] S2: forming a passivation layer on the surface of the semiconductor structure, and forming an electrode opening in the passivation layer above the ridge waveguide;

[0067] S3: performing Si ion implantation to form a doped compensation layer in the contact layer at the electrode opening, wherein the thickness of the doped compensation layer is smaller than the thickness of the contact layer;

[0068] S4: forming a P-side metal electrode filled in the electrode opening, wherein the P-side metal electrode includes an Au layer;

[0069] S5: performing local thermal annealing at the interface between the P-side metal electrode and the contact layer using a laser annealing process to form a gold silicide layer at the interface.

[0070] The above steps are described in detail below with reference to the structural diagram.

[0071] First see Figure 4 , performing the step S1: providing a semiconductor structure, the semiconductor structure comprising an InP substrate 201, an active layer 202, a waveguide layer 203 and a contact layer 204 arranged in sequence from bottom to top.

[0072] As an example, the active layer 202 can be epitaxially grown on the InP substrate 201. In some embodiments, the active layer 202 uses an indium gallium arsenide / indium phosphide (InGaAs / InP) multiple quantum well, which is composed of a plurality of alternating InGaAs quantum wells and InP quantum barriers. According to the quantum confinement effect, when electrons and holes are injected into the active region, they are confined in the InGaAs quantum well, and their movement is restricted in the direction perpendicular to the well wall, thereby quantizing the energy levels of electrons and holes. This quantized energy level is conducive to the recombination of electrons and holes. During the recombination process, energy is released in the form of photons to achieve laser emission. By adjusting the composition of In and Ga in the InGaAs quantum well and the thickness of the quantum well and barrier, a wide wavelength range can be covered.

[0073] As an example, the thickness of the active layer 202 ranges from 50 nm to 150 nm. For example, in one embodiment, the thickness of the active layer 202 is 100 nm.

[0074] As an example, the waveguide layer 203 may be obtained by epitaxial growth. In some embodiments, the waveguide layer 203 includes an InP layer and / or an InGaAsP layer.

[0075] Specifically, the waveguide layer 203 includes a ridge waveguide 203a. In some embodiments, the waveguide layer 203 is provided with grooves 203b defining the ridge waveguide 203a. These grooves 203b are formed in the waveguide layer 203 by a patterning process, such as photolithography, etching, or self-alignment. The step of patterning the waveguide layer 203 can be performed before or after the formation of the passivation layer and / or the metal electrode layer as needed, for example, before the formation of the passivation layer and / or the metal electrode layer. Figure 4 In a corresponding embodiment, the step of patterning the waveguide layer 203 is performed before the passivation layer is formed, wherein the ridge waveguide pattern is defined by photolithography, and the ridge waveguide is formed by ICP etching (Cl2 / Ar), deeply penetrating the waveguide layer 203 to the active layer 202.

[0076] As an example, the contact layer 204 may be grown on the surface of the waveguide layer 203 by epitaxial doping, and the contact layer 204 includes a P-type InGaAs layer.

[0077] As an example, the doping concentration range of the P-type InGaAs layer is 1E17-1E19 cm -3 For example, in one embodiment, the doping concentration range of the P-type InGaAs layer is 1E18 cm -3 .

[0078] As an example, the thickness of the P-type InGaAs layer ranges from 50 to 150 nm. For example, in one embodiment, the thickness of the P-type InGaAs layer is 100 nm.

[0079] See also Figure 5 , performing the step S2: forming a passivation layer 205 on the surface of the semiconductor structure, and forming an electrode opening 206 in the passivation layer 205 above the ridge waveguide 203a.

[0080] As an example, the material of the passivation layer 205 can be silicon dioxide, silicon nitride or other suitable materials, and can be deposited by plasma enhanced chemical vapor deposition (PECVD) or other suitable methods.

[0081] As an example, a photoresist may be coated on the passivation layer 205 , and an electrode window pattern may be formed after exposure and development. The passivation layer in the window area may be removed by RIE or wet etching to expose the contact layer 204 .

[0082] See also Figure 6 , performing step S3: performing Si ion implantation to form a doped compensation layer 207 in the contact layer 204 at the electrode opening 206 , wherein the bottom surface of the doped compensation layer 207 is higher than the bottom surface of the contact layer 204 .

[0083] Specifically, an important function of the Si ion implantation in this step is to neutralize the P-type doping on the surface of the contact layer 204 (P-type InGaAs layer), reduce the Schottky barrier, and thus obtain a smaller contact resistance.

[0084] Specifically, the passivation layer 205 serves as an ion implantation barrier layer, so that Si ions are implanted only into the contact layer 204 exposed by the electrode opening 206 .

[0085] Specifically, when performing Si ion implantation, the implantation dose needs to be controlled so as to neutralize only the P-type doping on the surface of the P-type InGaAs layer. At the same time, the implantation energy needs to be controlled to control the implantation depth, and ultimately a weak N-type layer is formed within a certain thickness range (for example, within 10 nm) on the surface of the contact layer 204, but this does not affect the heavy P-type doping of the contact layer 204 as a whole.

[0086] As an example, the dose range of the Si ion implantation is 1E15 to 9E15 cm -2 The energy range of the Si ion implantation is 2-10 keV. For example, in one embodiment, the dose of the Si ion implantation is 2E15 cm -2 , the energy of the Si ion implantation is 6keV.

[0087] As an example, the plane where the peak concentration of the Si ion implantation is located is located below the interface between the subsequently formed P-side metal electrode and the contact layer and the distance between the interface is 5 to 10 nm, and the thickness of the doping compensation layer is 5 to 10 nm.

[0088] See also Figure 7 , performing the step S4: forming a P-side metal electrode 208 filled in the electrode opening 206, wherein the P-side metal electrode 208 includes an Au layer.

[0089] Specifically, the Au layer can provide a low-resistance current path and facilitate wire bonding.

[0090] As an example, in order to improve the adhesion between the Au layer and the contact layer 204 , the P-side metal electrode 208 further includes a Ti layer, and the Au layer is located above the Ti layer.

[0091] It should be noted that a conventional Ti / Au electrode structure also includes a barrier layer (e.g., a Pt layer or other barrier metal) between the Ti layer and the Au layer to prevent the top layer of Au from diffusing into the layers below. However, in the present invention, the P-side metal electrode 208 does not include a barrier layer to facilitate the diffusion of Au into the contact layer 204 during the subsequent laser local thermal annealing process, thereby facilitating the formation of gold silicide.

[0092] In order to further optimize the Ti / Au electrode structure and increase the diffusion of Au, the present invention also reduces the thickness of the Ti layer.

[0093] As an example, the thickness of the Au layer ranges from 50 to 150 nm, and the thickness of the Ti layer is less than 10 nm. For example, in one embodiment, the P-side metal electrode 208 uses a 3 nm Ti layer and a 100 nm Au layer.

[0094] As an example, a metal layer is deposited by evaporation or other suitable methods to form the P-side metal electrode 208 .

[0095] As an example, a lift-off process is used to form a metal electrode pattern, that is, a photoresist layer is first formed and patterned, and then metal is deposited, wherein the area not covered by the photoresist forms an electrode, and the metal on the photoresist can be removed by lift-off to achieve a high-precision electrode pattern.

[0096] See also Figure 8 and Figure 9 , executing the step S5: performing local thermal annealing at the interface between the P-side metal electrode 208 and the contact layer 204 using a laser annealing process to form a gold silicide layer 210 at the interface, wherein, Figure 8The laser beam spot 209 is shown in FIG. Figure 9 Shown is a schematic diagram of the resulting structure after laser local thermal annealing.

[0097] Specifically, the purpose of the laser local thermal annealing in this step is to form an ohmic contact between the P-side metal electrode 208 and the contact layer 204. Based on the previous use of Si ion implantation to reduce the Schottky barrier to obtain a smaller contact resistance, this step can further reduce the contact resistance while retaining the adhesion of the Ti / Au electrode through the synergistic effect of silicon implantation and laser annealing, while avoiding damage to the active area caused by high-temperature annealing, thereby achieving a solution with simple process and controllable cost.

[0098] Specifically, in the process of performing local thermal annealing at the interface between the metal and the contact layer using a laser annealing process, it is necessary to control the temperature and annealing time to form gold silicide at the interface. The present invention adopts the following control scheme:

[0099] (1) Control the laser wavelength to match the absorption peak of InGaAs;

[0100] (2) Selecting an appropriate energy density to control the annealing temperature, ensuring that the heat can promote the formation of gold silicide by the injected Si and the diffused Au, effectively reducing the contact resistance, while avoiding the formation of Ti silicide (which has a higher resistance than gold silicide) due to excessive temperature;

[0101] (3) Select appropriate pulse width, control heating time, accelerate cooling time, and avoid diffusion of Ti into the laser active area at high temperature;

[0102] (4) Select a suitable focused spot and control the heating area, heating only the local area between the contact layer and the metal to avoid heating the active area at the same time, causing damage and reducing the performance of the laser.

[0103] Specifically, ideally, the laser annealing spot diameter is controlled to cover only the electrode area. However, since the laser beam spot shape may be inconsistent with the electrode shape, in some embodiments, the laser beam spot area used in the laser annealing process is controlled to be no larger than 120% of the electrode area.

[0104] As an example, the laser beam spot diameter used in the laser annealing process is less than 5 microns.

[0105] As an example, the laser annealing process uses a laser wavelength range of 510-550 nm and an energy density range of 1-5 J / cm 2 For example, in one embodiment, the laser wavelength used is 532 nm and the energy density is 3 J / cm 2 .

[0106] As an example, the laser annealing process uses a single pulse to complete annealing, and the pulse width range is 2 to 8 ms. For example, in one embodiment, the light spot is focused on the electrode area, and the annealing is completed by a single pulse with a pulse width of 5 ms.

[0107] At this point, the preparation of the InP laser Ti / Au electrode is completed. The silicon injection + laser annealing scheme of the present invention can effectively reduce the contact resistance between the P-side metal electrode 208 and the contact layer 204, wherein the Si injection can compensate for the P-type doping in the electrode area, and the reaction of the injected Si and the contact electrode metal Au is locally activated by laser annealing to form a low-resistance contact, and the scheme retains the excellent adhesion of the Ti / Au electrode. In addition, the manufacturing method of the InP laser structure of the present invention is compatible with existing processes, wherein the Si ion implantation utilizes a waveguide passivation layer as an injection barrier layer, and only laser annealing is used to replace traditional high-temperature annealing, which is compatible with the P-side metal electrode process of existing lasers. In addition, the method of the present invention can also achieve active area protection. Local laser annealing can reduce the impact of the process on the laser active area compared to conventional full-structure annealing, and avoid damage to the active area by high-temperature annealing. In summary, the manufacturing method of the InP laser structure of the present invention is simple in process and cost-controlled, and is suitable for mass production of high-performance InP lasers.

[0108] The present invention also provides an InP laser structure, which can be manufactured by using the manufacturing method of the InP laser structure described in any of the above schemes or other suitable schemes, see Figure 9 , which is a schematic diagram of the structure, includes, from bottom to top, an InP substrate 201, an active layer 202, a waveguide layer 203, and a contact layer 204, and includes a P-side metal electrode 208 and a gold silicide layer 210. The waveguide layer 203 includes a ridge waveguide 203a, the contact layer 204 includes a P-type InGaAs layer, the P-side metal electrode 208 is located above the ridge waveguide 203a and on the surface of the contact layer 204, the P-side metal electrode 208 includes an Au layer, and the gold silicide layer 210 is located at the interface between the P-side metal electrode 208 and the contact layer 204. The InP laser structure of the present invention has a gold silicide layer at the interface between the P-side metal electrode and the contact layer, resulting in lower contact resistance, higher quality of the active region, and good device performance.

[0109] In summary, the method for manufacturing an InP laser structure of the present invention forms an electrode opening in the passivation layer, then performs Si ion implantation to form a doped compensation layer in the contact layer at the electrode opening, wherein the bottom surface of the doped compensation layer is higher than the bottom surface of the contact layer, and then forms a P-side metal electrode including an Au layer filled in the electrode opening. Subsequently, a laser annealing process is used to perform local thermal annealing at the interface between the P-side metal electrode and the contact layer to form a gold silicide layer at the interface. The present invention, by implanting a certain dose of Si ions into the P-type InGaAs layer, can reduce the surface carrier concentration of the topmost layer of the device, thereby lowering the Schottky barrier and obtaining a lower contact resistance. On the other hand, during the subsequent laser annealing process, the injected Si ions react with the Au ions diffused to the surface of the contact layer to form a gold silicide layer, which can further reduce the contact resistance. At the same time, by controlling the laser beam spot size during the laser annealing process, the impact on the active area can be reduced, thereby improving product performance. The InP laser structure of the present invention features a gold silicide layer at the interface between the P-side metal electrode and the contact layer, resulting in lower contact resistance, a higher-quality active region, and excellent device performance. Therefore, the present invention effectively overcomes the shortcomings of existing technologies and possesses high industrial value.

[0110] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A method for manufacturing an InP laser structure, characterized in that: The following steps are involved: A semiconductor structure is provided, comprising an InP substrate, an active layer, a waveguide layer, and a contact layer arranged in sequence from bottom to top, wherein the waveguide layer comprises a ridge waveguide, and the contact layer comprises a P-type InGaAs layer; forming a passivation layer on the surface of the semiconductor structure, and forming an electrode opening in the passivation layer above the ridge waveguide; Performing Si ion implantation to form a doped compensation layer in the contact layer at the electrode opening, wherein the thickness of the doped compensation layer is smaller than the thickness of the contact layer; forming a P-side metal electrode filled in the electrode opening, wherein the P-side metal electrode comprises an Au layer; A laser annealing process is used to perform local thermal annealing at the interface between the P-side metal electrode and the contact layer to form a gold silicide layer at the interface.

2. The method for manufacturing an InP laser structure according to claim 1, wherein: The doping concentration range of the P-type InGaAs layer is 1E17 to 1E19 cm -3 The dose range of Si ion implantation is 1E15~9E15 cm -2 The energy range of the Si ion implantation is 2 to 10 keV.

3. The method for manufacturing an InP laser structure according to claim 1 or 2, wherein: The plane where the peak concentration of the Si ion implantation is located is located below the interface between the P-side metal electrode and the contact layer and the distance between the interface and the interface is in the range of 5 to 10 nm. The thickness of the doping compensation layer is in the range of 5 to 10 nm.

4. The method for manufacturing an InP laser structure according to claim 1, wherein: The P-side metal electrode further includes a Ti layer, the Au layer is located above the Ti layer, and the thickness of the Ti layer is less than 10 nm.

5. The method for manufacturing an InP laser structure according to claim 1 or 4, characterized in that: The thickness of the Au layer is in the range of 50 to 150 nm.

6. The method for manufacturing an InP laser structure according to claim 1, wherein: The laser beam spot area used in the laser annealing process is no greater than 120% of the electrode area.

7. The method for manufacturing an InP laser structure according to claim 1 or 6, characterized in that: The laser beam spot diameter used in the laser annealing process is less than 5 microns.

8. The method for manufacturing an InP laser structure according to claim 1 or 6, wherein: The laser annealing process uses a laser wavelength range of 510-550 nm and an energy density range of 1-5 J / cm 2 .

9. The method for manufacturing an InP laser structure according to claim 1 or 6, wherein: The laser annealing process uses a single pulse to complete annealing, and the pulse width range is 2 to 8 ms.

10. An InP laser structure, characterized in that: include: An InP substrate, an active layer, a waveguide layer, and a contact layer are sequentially arranged from bottom to top, wherein the waveguide layer includes a ridge waveguide, and the contact layer includes a P-type InGaAs layer; A P-surface metal electrode is located above the ridge waveguide and on the surface of the contact layer, wherein the P-surface metal electrode comprises an Au layer; A gold silicide layer is located at the interface between the P-side metal electrode and the contact layer.

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