High-speed laser chip and preparation method thereof

Abstract

The invention provides a high-speed laser chip and a preparation method thereof, and relates to the technical field of lasers. The preparation method comprises the following steps: growing a mask layer on the surface of an epitaxial wafer; transferring a single ridge waveguide pattern into the mask layer; forming a single ridge waveguide pattern on the surface of the epitaxial wafer through dry etching, performing wet etching on the epitaxial wafer on which the preliminary single ridge waveguide pattern is formed to prepare a single ridge waveguide structure, and removing the residual mask layer; growing an insulating layer on the surface of the epitaxial wafer; forming a benzocyclobutene layer on the surface of the insulating layer, and thinning the benzocyclobutene layer through reactive ion etching; growing a SiNx layer on the surface of the thinned benzocyclobutene layer, patterning the SiNx layer, and removing the SiNx layer on the single ridge waveguide structure; and growing P-surface metal and N-surface metal on the surface of the SiNx layer to prepare the high-speed laser chip. According to the invention, the problem that the bonding pad falls off during gold wire bonding of the laser chip containing the BCB material can be solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of laser, in particular to a high-speed laser chip and a preparation method thereof. BACKGROUND

[0002] High-speed laser is widely used in the field of intensity modulation-direct detection due to its simple structure and low cost. With the continuous improvement of transmission rate, the requirement for modulation bandwidth of laser is also increasing, so how to improve the modulation bandwidth of laser becomes a primary problem to be solved.

[0003] The parasitic capacitance of the laser chip is a key parameter affecting the modulation bandwidth of the laser chip, and the commonly used method for reducing the parasitic capacitance of the laser chip is to fill the material with low dielectric constant under the electrode pad, among which the dielectric constant of benzocyclobutene (also known as BCB) is the smallest and is the filling medium widely used at present. However, due to the poor adhesion between BCB and metal, the pad falls off during gold wire bonding. Therefore, how to improve the adhesion between BCB and metal is a primary problem to be solved. SUMMARY

[0004] In view of the above problems, the present application provides a high-speed laser chip and a preparation method thereof, which are used to at least partially solve the above technical problems.

[0005] According to a first aspect of the present application, a preparation method of a high-speed laser chip is provided, comprising the following steps: growing a mask layer on the surface of an epitaxial wafer; defining a single ridge waveguide pattern on the mask layer through a photolithography process, and transferring the single ridge waveguide pattern into the mask layer through an etching process; etching the epitaxial wafer through a dry etching process to form a single ridge waveguide pattern on the surface of the epitaxial wafer, wet etching the epitaxial wafer with the preliminary single ridge waveguide pattern formed thereon to prepare a single ridge waveguide structure, and removing the remaining mask layer; growing an insulating layer on the surface of the epitaxial wafer; forming a benzocyclobutene layer on the surface of the insulating layer, and thinning the benzocyclobutene layer through a reactive ion etching process; growing a SiN x layer on the surface of the thinned benzocyclobutene layer, patterning the SiN x layer through a photolithography and etching process, and removing the SiN x layer on the single ridge waveguide structure; growing P-face metal and N-face metal on the surface of the SiN x layer to prepare a high-speed laser chip.

[0006] According to the embodiment of the present application, the method for forming a benzocyclobutene layer on the surface of an insulating layer and thinning the benzocyclobutene layer by dry etching comprises: spin-coating a benzocyclobutene material on the surface of the insulating layer and curing the benzocyclobutene material to form a benzocyclobutene layer; removing the benzocyclobutene material above a predetermined cleaving groove area on the surface of the benzocyclobutene layer by using a photolithography process; and thinning the benzocyclobutene layer to a target thickness by reactive ion etching.

[0007] According to the embodiment of the present application, the gas used for the reactive ion etching is sulfur hexafluoride and oxygen.

[0008] According to the embodiment of the present application, the material of the mask layer is silicon dioxide, and the material of the insulating layer is silicon dioxide.

[0009] Before forming the benzocyclobutene layer on the surface of the insulating layer, the method comprises: removing the insulating layer outside the single ridge waveguide structure.

[0010] According to the embodiment of the present application, the thickness of the SiN x layer is 80nm-150nm, the width of the single ridge waveguide structure is 1.8μm-2.6μm, and the height of the single ridge waveguide structure is 1.6μm-2.0μm.

[0011] According to the embodiment of the present application, the P-face metal and the N-face metal are grown on the surface of the SiN x layer, and the method comprises: depositing a composite metal film comprising an adhesion layer, a barrier layer and a conductive layer on the surface of the SiN x layer by using a magnetron sputtering process; and patterning the composite metal film to manufacture a P-face pad, so as to reduce the area of the P-face metal and reduce the parasitic capacitance.

[0012] The second aspect of the present application provides a high-speed laser chip prepared according to the method for preparing a high-speed laser chip according to any one of the present disclosure.

[0013] According to the embodiment of the present application, the epitaxial wafer structure of the chip comprises, from bottom to top, a substrate, a buffer layer, a grating layer, a grating cover layer, a lower limiting layer, an active layer, an upper limiting layer, an etching stop layer, a cladding layer and a contact layer.

[0014] According to the embodiment of the present application, the insulating layer, the benzocyclobutene layer, the SiN x layer and the metal electrode layer are sequentially arranged above the etching stop layer, and the metal electrode layer comprises a P-face metal and an N-face metal.

[0015] According to the embodiment of the present application, the insulating layer, the benzocyclobutene layer, the SiN x layer wrap the cladding layer and the contact layer, and the metal electrode layer covers the contact layer.

[0016] The high-speed laser chip and the method for preparing the same provided by the present application at least have the following technical effects:

[0017] 1. Plasma bombardment, i.e., reactive ion etching, before the BCB process can effectively improve the adhesion between BCB and silicon dioxide, and also enhance the growth of SiN. x Plasma bombardment can effectively remove the underlying film and prevent the formation of metal and SiN. x The problem of insufficient adhesion between them can be solved by addressing the issue of pad detachment during gold wire bonding of laser chips containing BCB material.

[0018] 2. By coating a layer of BCB material on the insulating layer on the surface of the epitaxial wafer, the low dielectric constant of BCB material is used to reduce the parasitic capacitance of the laser chip, increase the relaxation oscillation frequency of the laser chip, and thus improve the modulation bandwidth of the laser chip. Attached Figure Description

[0019] The above-described features, other objects, and advantages of the present invention will become clearer from the following description of embodiments of the invention with reference to the accompanying drawings, in which:

[0020] Figure 1 A flowchart illustrating a method for fabricating a high-speed laser chip according to an embodiment of the present invention is shown schematically.

[0021] Figure 2 A schematic diagram of a high-speed laser chip according to an embodiment of the present invention is shown.

[0022] Figure 3 An electrode structure diagram of a high-speed laser chip according to an embodiment of the present invention is shown schematically;

[0023] Figure 4 A schematic diagram of the grating structure of a high-speed laser chip according to an embodiment of the present invention is shown.

[0024] Figure 5 A schematic diagram illustrating the relationship between the parasitic capacitance and modulation bandwidth of a high-speed laser chip according to an embodiment of the present invention is shown.

[0025] Figure label:

[0026] 201-Substrate; 202-Buffer layer; 203-Grating layer; 204-Grating cap layer; 205-Lower confinement layer; 206-Active layer; 207-Upper confinement layer; 208-Etching stop layer; 209-Cladding layer; 210-Contact layer; 211-Insulating layer; 212-Benzocyclobutene layer; 213-SiN x Layer; 214-metal electrode layer. Detailed Implementation

[0027] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the invention. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the invention for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0028] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0029] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0030] When using expressions such as "at least one of A, B and C", they should generally be interpreted in accordance with the meaning that is commonly understood by those skilled in the art (e.g., "a system having at least one of A, B and C" should include, but is not limited to, a system having A alone, a system having B alone, a system having C alone, a system having A and B, a system having A and C, a system having B and C, and / or a system having A, B and C, etc.).

[0031] Figure 1 A flowchart illustrating a method for fabricating a high-speed laser chip according to an embodiment of the present invention is shown.

[0032] like Figure 1 As shown, an embodiment of the present invention provides a method for fabricating a high-speed laser chip, comprising the following steps:

[0033] S1. A mask layer is grown on the surface of the epitaxial wafer;

[0034] S2. Define a single ridge waveguide pattern on the mask layer using photolithography, and transfer the single ridge waveguide pattern into the mask layer using etching.

[0035] S3. The epitaxial wafer is etched by dry etching process to form a single ridge waveguide pattern on the surface of the epitaxial wafer. The epitaxial wafer with the initial single ridge waveguide pattern is then wet etched to prepare the single ridge waveguide structure. The remaining mask layer is then removed.

[0036] S4. An insulating layer 211 is grown on the surface of the epitaxial wafer;

[0037] S5. A benzocyclobutene layer 212 is formed on the surface of the insulating layer 211, and the benzocyclobutene layer 212 is thinned by reactive ion etching.

[0038] S6. SiN is grown on the surface of the thinned benzocyclobutene layer 212. x Layer 213, patterned SiN using photolithography and etching processes. x Layer 213, removing SiN from the single ridge waveguide structure x Layer 213;

[0039] S7, in SiN x P-side and N-side metals are grown on the surface of layer 213 to fabricate a high-speed laser chip.

[0040] In the embodiments of this disclosure, plasma bombardment, i.e., reactive ion etching, performed before the BCB process can effectively improve the adhesion between BCB and silicon dioxide, and also enhance the growth of SiN. x Plasma bombardment can effectively remove the underlying film and prevent the formation of metal and SiN. x The problem of insufficient adhesion between them can be solved by addressing the issue of pad detachment during gold wire bonding of laser chips containing BCB material.

[0041] In step S5, a benzocyclobutene layer 212 is formed on the surface of the insulating layer 211, and the benzocyclobutene layer 212 is thinned by dry etching, including:

[0042] S501. Spin-coat benzocyclobutene material onto the surface of insulating layer 211 and cure it to form benzocyclobutene layer 212;

[0043] S502, Use photolithography to remove the benzocyclobutene material located above the predetermined cleavage channel region on the surface of the benzocyclobutene layer 212;

[0044] S503. The benzocyclobutene layer 212 is thinned to the target thickness by reactive ion etching.

[0045] It is important to understand that benzocyclobutene (BCB) is a novel high-performance microelectronic dielectric film material with characteristics such as low dielectric constant, high thermal conductivity, high bulk resistance, and strong insulation. Therefore, it can effectively reduce the parasitic capacitance of lasers and improve heat dissipation. BCB is classified into photosensitive and non-photosensitive types based on its light sensitivity; both types exhibit negative photoresist properties. The two types have different advantages and disadvantages: photosensitive BCB can directly achieve pattern transfer through photolithography, a simple process, but the pattern transfer accuracy is slightly lower and the price is slightly higher; non-photosensitive BCB has higher pattern accuracy, but requires multiple overlay steps to prepare a mask, followed by plasma etching for pattern transfer. In this embodiment of the invention, photosensitive BCB material is used to fill the lower layer of the electrode.

[0046] The BCB used in this invention is a photosensitive BCB, applied using a rotary coater, with DS2100 as the developer. The development method is immersion development, followed by curing in an oxygen-free oven. DS2100 is a commercially available developer developed by Dow Chemical (the original manufacturer of BCB) specifically for its photosensitive BCB products. Immersion development provides gentle action without mechanical impact, minimizing physical damage to intricate patterns (especially high aspect ratio structures). When BCB is exposed to oxygen at high temperatures (curing temperatures typically above 250°C), it undergoes a severe thermal oxidation reaction, leading to yellowing, brittleness, cracking, and deterioration of dielectric properties. Oxygen-free oven curing prevents the oxidative decomposition of the BCB.

[0047] For example, the thickness of the benzocyclobutene layer 212 after coating is 2.4μm~3μm, the development time is 1min~1min30s, and the baking temperature of the oxygen-free oven is 250℃.

[0048] The gases used in the reactive ion etching in step S503 above are sulfur hexafluoride and oxygen.

[0049] It's important to understand that reactive ion etching (RIE) is a mainstream, industrialized method for achieving plasma bombardment. It's a dry etching technique that utilizes the synergistic effect of chemically active free radicals and physical ion bombardment under low pressure. Its core lies in the directional acceleration of ions through a DC self-bias voltage, achieving highly anisotropic (vertical) pattern transfer.

[0050] The etching gases are sulfur hexafluoride and oxygen, which can avoid the degradation of BCB materials caused by physical bombardment because the reaction products are all gases. However, this is not suitable for inorganic materials (such as silicon dioxide and SiN). xFluorine / oxygen radicals react with these materials either very slowly or produce non-volatile products. Therefore, it is possible to effectively control the etching of only the BCB material, keeping the etching rate within a suitable range without affecting its ability to reduce the parasitic capacitance of the laser chip. It is important to note that the oxygen content in the etching gas should not be too high to avoid surface cracking of the BCB.

[0051] Furthermore, the mask layer is made of silicon dioxide, and the insulating layer 211 is made of silicon dioxide; before forming the benzocyclobutene layer 212 on the surface of the insulating layer 211, the insulating layer 211 outside the single ridge waveguide structure is removed.

[0052] SiO2 is a perfect insulator with high resistivity. As a mask layer: In subsequent ridge waveguide dry etching, SiO2 exhibits extremely high resistance to these etching gases (high etch selectivity), effectively protecting areas that will not be etched. As an insulating layer 211: During subsequent BCB filling and patterning processes, neither BCB nor the developer or etchant has much impact on SiO2, providing a stable process interface.

[0053] A continuous SiO2 insulating layer 211 was grown on the epitaxial wafer, and then a protruding ridge waveguide was formed by photolithography and etching. At this point, the top and sidewalls of the ridge waveguide were covered with SiO2. The SiO2 outside the ridge waveguide was etched away, leaving only a small area on the top of the ridge as the electrode contact area. Then, BCB was spin-coated, and the liquid BCB could flow smoothly and completely fill the spaces between the ridges. Since there was no obstruction from the large area of ​​side SiO2 walls, BCB could achieve planarization through spin-coating and curing.

[0054] Furthermore, SiN x The thickness of layer 213 is 80nm~150nm, if SiN x The thickness of layer 213 is too small to effectively improve the adhesion between BCB and the metal, while SiN... x If layer 213 is too thick, it will be difficult to effectively improve parasitic capacitance, because SiN x The dielectric constant of the material is too high, and the SiN filling is too thick. x Parasitic capacitance will actually increase further, causing a decrease in modulation.

[0055] The width of a single ridge waveguide structure is 1.8μm~2.6μm, and the height is 1.6μm~2.0μm. If the height of a single ridge waveguide structure is too low, the lateral confinement factor of the laser chip is too small, making it difficult to confine the lateral modes of the laser chip. If the height of a single ridge waveguide structure is too high, the series resistance will increase sharply, leading to severe heat generation and reduced efficiency. If the width of a single ridge waveguide structure is too narrow, the current injection efficiency will decrease, and the excessive current density will increase the thermal effect, increase the damping factor of the laser chip, and reduce the modulation bandwidth of the laser. If the width of a single ridge waveguide structure is too wide, the lateral confinement effect of the laser chip will be reduced.

[0056] In step S7, in SiN x Layer 213 has P-plane and N-plane metals grown on its surface, including:

[0057] S701, in SiN x A composite metal film comprising an adhesion layer, a barrier layer and a conductive layer is deposited on the surface of layer 213 using a magnetron sputtering process.

[0058] S702 patterns the composite metal film to create P-side pads, thereby reducing the area of ​​the P-side metal and lowering parasitic capacitance.

[0059] After the P-side metal growth, the laser chip needs to be thinned by grinding and polishing. The thickness of the thinned laser chip is 100μm~130μm.

[0060] Figure 2 A schematic diagram of a high-speed laser chip according to an embodiment of the present invention is shown. Figure 3 An electrode structure diagram of a high-speed laser chip according to an embodiment of the present invention is shown schematically.

[0061] like Figure 2 As shown, an embodiment of the present invention also provides a high-speed laser chip, which is prepared according to the preparation method of the high-speed laser chip in any of the above embodiments.

[0062] In this embodiment, the epitaxial wafer structure of the high-speed laser chip includes, from bottom to top, a substrate 201, a buffer layer 202, a grating layer 203, a grating cap layer 204, a lower confinement layer 205, an active layer 206, an upper confinement layer 207, an etch stop layer 208, a cladding layer 209, and a contact layer 210.

[0063] The grating layer 203, located on the N-plane, leverages the greater electron mobility than hole mobility to reduce the parasitic resistance of the laser chip, thereby improving the modulation bandwidth. The active layer 206 generates the laser; upon injection of current, electrons and holes recombine in this region to produce photons. The etching cutoff layer 208, during subsequent dry or wet etching processes for fabricating ridge waveguides, experiences extremely high selectivity, causing the process to automatically slow down or stop significantly. This ensures that all ridge waveguides have completely consistent heights, crucial for guaranteeing device performance uniformity.

[0064] like Figure 3 As shown, an insulating layer 211, a benzocyclobutene layer 212, and a SiN layer are sequentially disposed above the corrosion stop layer 208. x Layer 213 and metal electrode layer 214, the metal electrode layer 214 including P-side metal and N-side metal, insulating layer 211, benzocyclobutene layer 212, SiN x Layer 213 encapsulates layer 209 and contact layer 210, and metal electrode layer 214 covers contact layer 210.

[0065] The cladding 209, located above the etched stop layer 208, forms the main body of the ridge waveguide. It not only further assists in confining the optical field but also provides the primary vertical path for current to flow downwards from the top electrode to the active region. Removing the cladding 209 on both sides through subsequent etching (forming ridges) achieves lateral current confinement. The contact layer 210, grown at the very top, is extremely thin but has a very high doping concentration. When in contact with the metal electrode, it forms a non-rectifying ohmic contact with extremely low barrier and very low resistance, ensuring efficient current injection.

[0066] The total thickness of the laser chip is between 100μm and 130μm. If the laser chip is too thick, the series resistance of the laser will increase and the modulation bandwidth of the laser will decrease. At the same time, if the laser chip is too thick, it will be difficult to achieve optical coupling of the laser in the subsequent packaging process, which will affect the output power of the laser.

[0067] It's important to understand that the higher the relaxation frequency of a laser chip, the larger its 3dB bandwidth, and the relaxation frequency is closely related to photon density. Traditional... Phase-shifting gratings increase photon density in the cavity due to photon density accumulation in the phase-shift region. Higher photon density leads to a lower relaxation oscillation frequency, affecting the laser's 3dB bandwidth. Grating layer 203, composed of periodically modulated gratings, effectively improves the photon density in the cavity, reduces the laser's photon lifetime, and effectively decreases the laser's linewidth broadening factor, thus improving the laser's 3dB bandwidth to a certain extent.

[0068] Figure 4A schematic diagram of the grating structure of a high-speed laser chip according to an embodiment of the present invention is shown. Figure 4 As shown, the grating period of grating layer 203 satisfies:

[0069]

[0070] in, The grating period is the period of the non-modulated region. The grating period of the modulation region. The length of the modulation grating. The length ranges from 0.15L to 0.3L, where L is the total length of the grating layer 203.

[0071] The grating propagation constant of the modulation region is:

[0072]

[0073] The grating propagation constant in the unmodulated region is:

[0074]

[0075] The phase shift experienced is:

[0076]

[0077] To ensure that the phase shift introduced by the modulation region is π / 2, let ,Will and Substitution From this, we can obtain:

[0078]

[0079] To ensure that the phase shift introduced by the modulation region is π / 2, the grating period of the modulation region and the grating period of the non-modulation region should satisfy the relationship in the above formula.

[0080] The laser chip of this invention, compared to traditional... Phase-shifting gratings can reduce spatial hole burning and low-frequency roll-off effects. By using periodically modulated gratings, the photon density in the phase-shifting region can be reduced, effectively mitigating the spatial hole burning effect. By changing the duty cycle of the grating, the deterioration of the side-mode suppression ratio caused by the abrupt change in refractive index at both ends of the grating can be improved.

[0081] Figure 5 A schematic diagram illustrating the relationship between the parasitic capacitance and modulation bandwidth of a high-speed laser chip according to an embodiment of the present invention is shown.

[0082] like Figure 5As shown, the parasitic capacitance of the laser originates from the capacitance between the P-side electrode and the active region of the chip. As the parasitic capacitance increases, the relaxation oscillation frequency intensity of the laser chip continuously decreases, which severely limits the modulation bandwidth of the laser chip. By reducing the parasitic capacitance, the 3dB bandwidth of the laser chip can be effectively improved.

[0083] Those skilled in the art will understand that the features described in the various embodiments of the present invention can be combined or combined in various ways, even if such combinations or combinations are not explicitly described in the present invention. In particular, the features described in the various embodiments of the present invention can be combined and / or combined in various ways without departing from the spirit and teachings of the present invention. All such combinations and / or combinations fall within the scope of the present invention.

[0084] The embodiments of the present invention have been described above. However, these embodiments are merely illustrative and not intended to limit the scope of the invention. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. The scope of the invention is defined by the appended claims and their equivalents. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of the invention, and all such substitutions and modifications should fall within the scope of the invention.

Claims

1. A method for fabricating a high-speed laser chip, characterized in that, Includes the following steps: A mask layer is grown on the surface of the epitaxial wafer; A single ridge waveguide pattern is defined on the mask layer using photolithography, and the single ridge waveguide pattern is transferred to the mask layer using etching. The epitaxial wafer is etched using a dry etching process to form a single-ridge waveguide pattern on the surface of the epitaxial wafer. The epitaxial wafer with the initial single-ridge waveguide pattern is then subjected to wet etching to fabricate a single-ridge waveguide structure. The remaining mask layer is then removed. An insulating layer (211) is grown on the surface of the epitaxial wafer. A benzocyclobutene layer (212) is formed on the surface of the insulating layer (211), and the benzocyclobutene layer (212) is thinned by reactive ion etching; SiN was grown on the surface of the thinned benzocyclobutene layer (212). x Layer (213), patterned using photolithography and etching processes, is used to pattern the SiN. x Layer (213), removing the SiN on the single ridge waveguide structure x Layer (213); In the SiN x P-plane metal and N-plane metal are grown on the surface of layer (213) to form the high-speed laser chip.

2. The method for fabricating a high-speed laser chip according to claim 1, characterized in that, The process of forming a benzocyclobutene layer (212) on the surface of the insulating layer (211) and thinning the benzocyclobutene layer (212) by dry etching includes: Benzocyclobutene material is spin-coated onto the surface of the insulating layer (211) and cured to form a benzocyclobutene layer (212). The benzocyclobutene material located above the predetermined cleavage channel region is removed from the surface of the benzocyclobutene layer (212) using a photolithography process; The benzocyclobutene layer (212) was thinned to the target thickness by reactive ion etching.

3. The method for fabricating a high-speed laser chip according to claim 1, characterized in that, The gases used in the reactive ion etching are sulfur hexafluoride and oxygen.

4. The method for fabricating a high-speed laser chip according to claim 1, characterized in that, The mask layer is made of silicon dioxide, and the insulating layer (211) is made of silicon dioxide. Before forming the benzocyclobutene layer (212) on the surface of the insulating layer (211), the process includes removing the insulating layer (211) outside the single ridge waveguide structure.

5. The method for fabricating a high-speed laser chip according to claim 1, characterized in that, The SiN x The thickness of layer (213) is 80nm~150nm, the width of the single ridge waveguide structure is 1.8μm~2.6μm, and the height is 1.6μm~2.0μm.

6. The method for fabricating a high-speed laser chip according to claim 1, characterized in that, The SiN x Layer (213) has P-plane and N-plane metals grown on its surface, including: In the SiN x The surface of layer (213) is deposited with a composite metal film containing an adhesion layer, a barrier layer and a conductive layer by magnetron sputtering. The composite metal film is patterned to create P-side pads, thereby reducing the area of ​​the P-side metal and lowering parasitic capacitance.

7. A high-speed laser chip, characterized in that, The chip is prepared by the method for preparing a high-speed laser chip according to any one of claims 1-6.

8. The high-speed laser chip according to claim 7, characterized in that, The epitaxial wafer structure of the chip includes, from bottom to top, a substrate (201), a buffer layer (202), a grating layer (203), a grating cap layer (204), a lower confinement layer (205), an active layer (206), an upper confinement layer (207), an etch stop layer (208), a cladding layer (209), and a contact layer (210).

9. The high-speed laser chip according to claim 8, characterized in that, An insulating layer (211), a benzocyclobutene layer (212), and a SiN layer are sequentially disposed above the corrosion stop layer (208). x The layer (213) and the metal electrode layer (214) include P-side metal and N-side metal.

10. The high-speed laser chip according to claim 9, characterized in that, The insulating layer (211), the benzocyclobutene layer (212), and the SiN x The layer (213) encloses the cladding layer (209) and the contact layer (210), and the metal electrode layer (214) covers the contact layer (210).

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