Fabrication method of on-chip gain waveguide based on deposition-injection dynamic cycle process

Abstract

The application discloses a preparation method of a gain waveguide on a chip based on a deposition-injection dynamic circulation process. The method combines thin film growth and conventional ion injection equipment, and can realize high-depth ion injection effect, overcome the dependence of ion injection on high-energy ion injection equipment, reduce the preparation equipment requirements and production cost, and is easy to expand in mass production. In addition, through the processes of sequentially performing annealing process treatment, photolithography process treatment and etching process treatment, the preparation process is simplified, the waveguide deformation caused by high-flux ion injection and the film shrinkage effect caused by high-temperature annealing are effectively relieved, the waveguide structure morphology quality is improved, and light scattering loss is reduced.

Description

Technical Field

[0001] This application relates to the field of optical waveguide fabrication technology, and in particular to an on-chip gain waveguide fabrication method based on a deposition-injection dynamic cycle process. Background Technology

[0002] As communication networks evolve towards higher bandwidth and lower latency, the demand for high-performance, low-noise on-chip optical amplifiers is becoming increasingly urgent. Researchers have achieved efficient optical amplification by embedding ions into waveguides such as silicon-based silicon nitride, utilizing the high optical field confinement capability of the waveguides. This technological approach not only inherits the low-noise advantage of fiber optic amplifiers but also achieves compatibility with photonic integrated circuits, significantly reducing system size, power consumption, and cost, thus giving rise to the waveguide amplifier technology route.

[0003] Waveguide amplifiers, as on-chip gain devices based on planar optical waveguide technology, hinge on how rare-earth ions are doped into the waveguide material. Ion implantation, as a crucial doping method, offers significant advantages in waveguide amplifiers, and implantation energy is one of the core parameters in the ion implantation process, directly determining the penetration depth of ions within the waveguide material. To achieve optimal overlap with the optical field mode, the optical waveguide must be relatively deep, necessitating the use of high-energy ion implanters to implant ions to a sufficient thickness.

[0004] However, high-energy ion implanters require stronger accelerating electric fields and vacuum systems, resulting in high equipment costs. Furthermore, while high-energy ion implantation achieves deeper ion penetration, it also generates more lattice defects due to collisions, making annealing more difficult. The market urgently needs to develop new ion implantation processes that can achieve high-penetration deep structures while reducing the equipment requirements, facilitating large-scale production and integration, and driving the development of high-speed optical interconnects and integrated photonics. Summary of the Invention

[0005] This application aims to at least solve the technical problems existing in the prior art. To this end, the first aspect of this application proposes an on-chip gain waveguide fabrication method based on a deposition-injection dynamic cycle process, the method comprising:

[0006] A thin film of optical waveguide material of a predetermined thickness is grown on a cleaned and polished substrate using a thin film manufacturing process. Then, ions to be implanted are implanted into the newly grown optical waveguide material film using a conventional ion implantation device to obtain the current film after ion implantation. The predetermined thickness is less than the predetermined total film growth thickness, and the current ion implantation energy of the conventional ion implantation device is less than one megaelectron volt.

[0007] The above steps are repeated for a preset number of cycles corresponding to the deposition-implantation dynamic cycle process until the target ion implantation depth is reached, thereby obtaining the target thin film after ion implantation; wherein, the target ion implantation depth is the same as the preset total film growth thickness, and the preset number of cycles is determined based on the preset thickness and the preset total film growth thickness; the deposition-implantation dynamic cycle process includes the thin film production process and the ion implantation process, and the thin film production process and the ion implantation process are performed alternately;

[0008] The target thin film after ion implantation is sequentially subjected to annealing, photolithography and etching processes to prepare the current on-chip gain waveguide.

[0009] After stripping and cleaning the current on-chip gain waveguide, a capping layer is deposited to prepare the target on-chip gain waveguide.

[0010] In one possible implementation, the preset thickness is determined based on the material of the optical waveguide thin film, the ions to be implanted, and the current ion implantation energy.

[0011] In one possible implementation, the preset thickness of the optical waveguide material film grown during the first deposition-injection dynamic cycle process is the largest.

[0012] In one possible implementation, ions to be implanted are implanted into a newly grown optical waveguide material thin film using a conventional ion implantation device to obtain the current thin film after ion implantation, including:

[0013] A multi-step ion implantation process is used to implant ions into a newly grown optical waveguide material film to obtain the current film after ion implantation; wherein, the current ion implantation energy in the multi-step ion implantation process can be adjusted.

[0014] In one possible implementation, the target thin film after ion implantation is sequentially subjected to annealing, photolithography, and etching processes to fabricate the current on-chip gain waveguide, including:

[0015] The target thin film after ion implantation is first subjected to an annealing process to repair lattice defects and activate the implanted ions, resulting in an annealed target thin film.

[0016] Then, a photolithography process is performed to transfer the pre-designed waveguide structure and stress relief structure from the preset mask onto the annealed target film, thus obtaining the photolithographic target film.

[0017] Finally, an etching process is performed to fabricate the waveguide structure and stress relief structure on the photolithographic target thin film, resulting in the current on-chip gain waveguide.

[0018] In one possible implementation, the substrate is a silicon wafer made of silicon dioxide, the optical waveguide material film is a silicon nitride film, and the ions to be implanted are erbium ions. An optical waveguide material film of a predetermined thickness is grown on a cleaned and polished substrate. Then, the ions to be implanted are implanted into the optical waveguide material film using a conventional ion implantation device to obtain the current film after ion implantation, including:

[0019] A silicon nitride thin film of a predetermined thickness is grown on a silicon wafer containing cleaned and polished silicon dioxide. Erbium ions are then implanted into the silicon nitride thin film using a conventional ion implantation device with an ion implantation energy of 500 keV to obtain the current thin film after ion implantation. The current thin film after ion implantation is the current silicon nitride thin film implanted with erbium ions.

[0020] In one possible implementation, the preset number of cycles for the deposition-implantation dynamic cycling process is four, the preset thickness of the silicon nitride film grown in the first cycle is 200 nm, and the preset thickness of the silicon nitride film grown in the subsequent three cycles is 150 nm each.

[0021] In one possible implementation, the target thin film after ion implantation is a target silicon nitride thin film implanted with erbium ions. The target thin film after ion implantation is subjected to annealing, photolithography, and etching processes in sequence to prepare the current on-chip gain waveguide, including:

[0022] The target silicon nitride thin film implanted with erbium ions is annealed at 1000°C in nitrogen for 1 hour, followed by photolithography and etching processes to prepare the current on-chip gain waveguide; wherein, the current on-chip gain waveguide is the current erbium-doped silicon nitride waveguide.

[0023] In one possible implementation, the target on-chip gain waveguide is fabricated by depositing a capping layer after stripping and cleaning the current on-chip gain waveguide, including:

[0024] After stripping and cleaning the current erbium-doped silicon nitride waveguide, a silicon dioxide capping layer is deposited to prepare the target on-chip gain waveguide; wherein, the target on-chip gain waveguide is the target erbium-doped silicon nitride waveguide.

[0025] The second aspect of this application proposes an on-chip gain waveguide, which is fabricated according to the on-chip gain waveguide fabrication method based on the deposition-injection dynamic cycle process described in the first aspect above.

[0026] The embodiments of this application have the following beneficial effects:

[0027] This application provides a method for fabricating an on-chip gain waveguide based on a deposition-implantation dynamic cyclic process. The method includes: growing an optical waveguide material film of a predetermined thickness on a cleaned and polished substrate using a thin film fabrication process; then implanting ions into the newly grown optical waveguide material film using a conventional ion implantation device to obtain the current film after ion implantation. The predetermined thickness is less than the predetermined total film growth thickness, and the current ion implantation energy of the conventional ion implantation device is less than one megaelectron volt. The above steps are repeated for a predetermined number of cycles corresponding to the deposition-implantation dynamic cyclic process until the target ion implantation depth is reached to obtain the target film after ion implantation. The target film after ion implantation is then subjected to annealing, photolithography, and etching processes to prepare the current on-chip gain waveguide. Finally, the current on-chip gain waveguide is subjected to a stripping and cleaning process, followed by deposition of a capping layer to prepare the target on-chip gain waveguide. This approach combines thin film growth with conventional ion implantation equipment to achieve high-depth ion implantation, overcoming the dependence of ion implantation on high-energy ion implantation equipment, reducing equipment requirements and production costs, and facilitating large-scale production. Furthermore, by sequentially performing annealing, photolithography, and etching processes, the fabrication process is simplified while effectively mitigating waveguide deformation caused by high-throughput ion implantation and thin film shrinkage effects from high-temperature annealing. This improves the waveguide structure morphology quality and reduces light dissipation. Attached Figure Description

[0028] Figure 1 A schematic diagram of a conventional deposition-injection process provided in this application;

[0029] Figure 2 A flowchart illustrating the steps of an on-chip gain waveguide fabrication method based on a deposition-injection dynamic cyclic process, provided in this application embodiment;

[0030] Figure 3 A schematic diagram of a deposition-injection dynamic circulation process provided in this application;

[0031] Figure 4 A flowchart illustrating the steps for fabricating an on-chip gain waveguide, as provided in this application embodiment;

[0032] Figure 5 A schematic diagram illustrating the relationship between injection depth and injection energy provided in this application;

[0033] Figure 6 A schematic diagram of the fundamental transverse magnetic mode optical field distribution in an erbium-doped silicon nitride waveguide with a thickness of 700 nm provided in this application;

[0034] Figure 7A schematic diagram of the fundamental transverse magnetic mode optical field distribution in an erbium-doped silicon nitride waveguide with a thickness of 200 nm provided in this application;

[0035] Figure 8 This is a schematic diagram of a process for fabricating a target erbium-doped silicon nitride waveguide, as provided in this application. Detailed Implementation

[0036] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0037] With the rapid development of technologies such as 5G / 6G communication, data centers, the Internet of Things, artificial intelligence, and quantum information processing, the demand for information transmission and processing is exploding. Particularly in the field of optical communication, although high-efficiency erbium-doped fiber amplifiers (EDFAs) are core components for achieving long-term, high-capacity transmission, their design philosophy fundamentally conflicts with the new demands for integration. The core of an EDFA is a several-meter-long erbium-doped silica fiber, relying on a high-power pump source to excite erbium ion energy level transitions to amplify the optical signal. This discrete device-based architecture results in a large system size and high power consumption, making it difficult to be compatible with silicon-based photonic chips and meet the demands of modern information technology for miniaturization, low power consumption, and high performance. As communication networks evolve towards higher bandwidth and lower latency, the need for high-performance, low-noise on-chip optical amplifiers is becoming increasingly urgent. Against this backdrop, researchers have turned their attention to rare-earth-doped waveguide materials, namely, by embedding rare-earth ions into silicon-based silicon nitride waveguides, utilizing the high optical field confinement capability of the waveguides to achieve efficient optical amplification. This technological approach not only inherits the low-noise advantage of fiber optic amplifiers, but also achieves compatibility with photonic integrated circuits, significantly reducing system size, power consumption, and cost, thus giving rise to the waveguide amplifier technology route.

[0038] Waveguide amplifiers, as on-chip gain devices based on planar optical waveguide technology, hinge on the core principle of rare-earth ion doping into the waveguide material. Ion implantation, as a crucial doping method, offers significant advantages in optical waveguide amplifiers, such as precise control of doping concentration and distribution, material compatibility and flexibility, reliance on room and low-temperature environments, high spatial resolution, and compatibility with semiconductor processes. Implantation energy is a critical parameter in ion implantation, directly determining the penetration depth of ions within the material. To achieve optimal overlap with the optical field, the waveguide needs to be relatively deep, necessitating a high primary ion implantation energy to achieve sufficient rare-earth ion implantation thickness. For example, current technology uses an implantation energy of 2 MeV to achieve approximately 700 nm of erbium ion implantation in silicon nitride waveguides. However, high-energy ion implanters require stronger accelerating electric fields and vacuum systems, resulting in high equipment costs. Furthermore, while high-energy particle implantation achieves deeper particle penetration, it also generates more lattice defects due to collisions (such as vacancies and interstitial atoms), making annealing more challenging. The market urgently needs to develop new ion implantation processes that can reduce the equipment requirements while ensuring high penetration into deep structures, making it easier to achieve large-scale production and integration, and promoting the development of high-speed optical interconnects and integrated photonics.

[0039] like Figure 1 As shown, Figure 1 This illustration shows a traditional deposition-implantation process, using rare-earth ion implantation as an example. The traditional deposition-implantation process includes thin film growth and ion implantation. A thin film with a predetermined total thickness of h can be grown using methods such as low-pressure chemical vapor deposition (LPCVD) or plasma-enhanced chemical vapor deposition (PECVD). Rare-earth ions are then implanted into the thin film using an ion implanter. Because rare-earth ions have significantly higher atomic weights than common dopant ions, they lose kinetic energy more quickly when colliding with substrate atoms at the same implantation energy, leading to decreased penetration and limited implantation depth. Furthermore, when the larger rare-earth ions collide with substrate atomic nuclei, the nuclear blocking effect dominates, accelerating ion stopping and further shortening the implantation depth. Ion implantation depth is positively correlated with energy; therefore, achieving high-depth rare-earth ion implantation necessitates the use of high-energy ion implantation equipment. If a conventional ion implanter is used, the rare-earth ion implantation depth will inevitably be shallow, with the rare-earth ions mainly distributed in the shallow surface layer of the thin film. This severely reduces the overlap factor between rare-earth ions and the optical field mode, significantly limiting the performance of on-chip gain devices.

[0040] In view of this, this application proposes an on-chip gain waveguide fabrication method based on a deposition-implantation dynamic cycle process. This method achieves high-depth ion implantation by combining thin film growth and conventional ion implantation equipment, overcoming the dependence of ion implantation on high-energy ion implantation equipment, reducing the requirements for fabrication equipment and production costs, and is easily scalable for mass production. In addition, by sequentially performing annealing, photolithography, and etching processes, the fabrication process is simplified while effectively mitigating waveguide deformation caused by high-throughput ion implantation and thin film shrinkage caused by high-temperature annealing. This improves the waveguide structure morphology quality and reduces light dissipation.

[0041] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of this disclosure, unless otherwise stated, "a plurality of" means two or more. Furthermore, the use of "based on" or "according to" implies openness and inclusiveness, because processes, steps, calculations, or other actions "based on" or "according to" one or more of the stated conditions or values ​​may in practice be based on additional conditions or beyond the stated values.

[0042] like Figure 2 As shown, Figure 2 A flowchart illustrating the steps of an on-chip gain waveguide fabrication method based on a deposition-injection dynamic cyclic process, provided in this application embodiment, includes:

[0043] Step 202: Using thin film production technology, grow an optical waveguide material thin film of a predetermined thickness on a cleaned and polished substrate. Then, using ion implantation technology, implant ions to be implanted into the newly grown optical waveguide material thin film through conventional ion implantation equipment to obtain the current thin film after ion implantation.

[0044] The preset thickness refers to the thickness of each newly grown optical waveguide material film, and this preset thickness is less than the preset total film growth thickness. The current ion implantation energy of a conventional ion implantation device is less than one megaelectron volt; for example, the current ion implantation energy of a conventional ion implantation device is typically 500 keV.

[0045] In some optional embodiments, the preset thickness is determined based on the material of the optical waveguide film, the ions to be implanted, and the current ion implantation energy. It should be noted that the preset thickness can be adaptively adjusted according to actual needs. Optionally, the current ion implantation energy of a conventional ion implantation device can be flexibly selected. For example, if the maximum current ion implantation energy is 500 keV, a value less than or equal to 500 keV can be selected according to actual requirements, thereby changing the preset thickness.

[0046] In some alternative embodiments, the preset thickness of the optical waveguide material film grown each time can be the same, so that it is not necessary to select the current ion implantation energy of the conventional ion implantation equipment multiple times, thereby improving the growth efficiency of the optical waveguide material film.

[0047] In some alternative embodiments, the preset thickness of the first grown optical waveguide material film is the largest during the deposition-implantation dynamic cycle process. Optionally, during the cycle, the preset thickness of each subsequent grown optical waveguide material film can be the same or different, and can be customized according to actual needs. Furthermore, after determining the maximum preset thickness of the first grown optical waveguide material film, the preset thickness of each subsequent grown optical waveguide material film can also be determined by the peak concentration of implanted ions under the current ion implantation energy conditions of a conventional ion implantation device. This method can achieve a relatively flat ion distribution morphology.

[0048] Then, a thin-film optical waveguide material film of a predetermined thickness can be grown on a cleaned and polished substrate using thin-film manufacturing processes. Next, ion implantation is performed using conventional ion implantation equipment to implant ions into the newly grown optical waveguide material film, resulting in the current film after ion implantation. The ions to be implanted here are ions with large atomic mass, which can be rare earth ions or other element ions with large atomic mass. This embodiment uses rare earth ion implantation as an example for illustration.

[0049] In some alternative embodiments, implanting ions to be implanted into the newly grown optical waveguide material film using conventional ion implantation equipment to obtain the current film after ion implantation may include: using a multi-step ion implantation process to implant ions to be implanted into the newly grown optical waveguide material film to obtain the current film after ion implantation.

[0050] In the multi-step ion implantation process, the current ion implantation energy can be adjusted. For example, if the current maximum ion implantation energy is 500 keV, a multi-step ion implantation method can be adopted each time ion implantation is performed. For each step of ion implantation, a value less than or equal to 500 keV can be selected according to actual needs.

[0051] In this embodiment, a multi-step ion implantation process was adopted to achieve precise control over the concentration distribution and morphology of implanted rare earth ions.

[0052] Step 204: Repeat the above steps for the preset number of cycles corresponding to the deposition-implantation dynamic cycle process until the target ion implantation depth is reached, and obtain the target thin film after ion implantation.

[0053] The target ion implantation depth is the same as the preset total film growth thickness, and the preset number of cycles is determined based on the preset thickness and the preset total film growth thickness. The aforementioned deposition-implantation dynamic cycling process includes a film production process and an ion implantation process, which are performed alternately.

[0054] This allows for the repeated execution of a process where a pre-defined optical waveguide material film of a predetermined thickness is grown on a cleaned and polished substrate using thin film manufacturing technology. Then, ions to be implanted are implanted into the newly grown optical waveguide material film using a conventional ion implantation process, resulting in the current film after ion implantation. This process continues in a cyclic deposition-implantation process, and finally, by repeating the process a predetermined number of times to achieve the target ion implantation depth, the target film after ion implantation is obtained.

[0055] like Figure 3 As shown, Figure 3 This diagram illustrates a deposition-implantation dynamic cycling process provided in this application, using rare earth ion implantation as an example. N represents the preset number of cycles, which can be determined by the preset thickness and the preset total film growth thickness h. Alternatively, the preset thickness of the optical waveguide material film grown each time can be calculated using the ratio of h to N.

[0056] Step 206: After ion implantation, the target thin film is subjected to annealing, photolithography and etching processes in sequence to prepare the current on-chip gain waveguide.

[0057] After obtaining the target thin film after ion implantation, the target thin film can be subjected to annealing, photolithography and etching processes in sequence to prepare the current on-chip gain waveguide.

[0058] In some alternative embodiments, such as Figure 4 As shown, Figure 4 A flowchart illustrating the steps for fabricating an on-chip gain waveguide, as provided in this application embodiment, includes:

[0059] Step 402: Perform an annealing process on the target thin film after ion implantation to repair lattice defects and activate the implanted ions, thereby obtaining the annealed target thin film.

[0060] Step 404: Perform photolithography to transfer the pre-designed waveguide structure and stress relief structure from the preset mask onto the annealed target film, thus obtaining the photolithographic target film.

[0061] Step 406: Finally, perform an etching process to fabricate the waveguide structure and stress relief structure on the photolithographic target thin film to obtain the current on-chip gain waveguide.

[0062] After the deposition-implantation dynamic cycle process, the required ion implantation thickness is achieved. Then, the annealing-photolithography-etching process is required. The annealing-photolithography-etching process in this application mainly includes rapid annealing, photolithography, and etching. The rapid annealing process has two main functions: repairing lattice defects caused by ion implantation and activating the implanted ions. The photolithography process is used to transfer the pre-designed waveguide structure and stress relief structure from the preset mask to the target thin film after annealing. The etching process is used to complete the fabrication of the designed waveguide structure.

[0063] The sequence of processes in this application is also a key feature. The deposition-implantation dynamic cycle process requires ion implantation to be completed before the annealing-photolithography-etching process, i.e., waveguide structure fabrication is performed only after the annealing-photolithography-etching process. This saves time by allowing waveguide fabrication to be completed in a single step, eliminating the need for waveguide structure fabrication after each film growth. Furthermore, by ion implanting the entire film material instead of the waveguide structure, waveguide deformation caused by high-throughput ion implantation is completely avoided. Additionally, the annealing-photolithography-etching process must strictly adhere to the annealing, photolithography, and etching sequence. This is because high-temperature annealing produces a film shrinkage effect, which significantly affects the waveguide structure, causing unpredictable bending and thus impacting the light field distribution within the waveguide, leading to light scattering. However, performing high-temperature annealing first, followed by photolithography and etching, effectively avoids this phenomenon and helps improve the morphology quality of the optical waveguide.

[0064] Step 208: After stripping and cleaning the current on-chip gain waveguide, a capping layer is deposited to prepare the target on-chip gain waveguide.

[0065] After obtaining the current on-chip gain waveguide, a stripping and cleaning process can be used to remove residual mask layers and other impurities. Finally, a capping layer is deposited on the fabricated ion-doped waveguide structure to protect the waveguide structure, thus obtaining the final target on-chip gain waveguide.

[0066] In some alternative embodiments, this application provides the use of a silicon wafer with high-quality silicon dioxide as the substrate, silicon nitride (Si3N4) as the optical waveguide material, and erbium ions (Er) as the optical waveguide material. 3+For the ions to be implanted, the current implantation energy of conventional ion implantation equipment is 500 keV. It should be noted that this method can also be applied to other implanted ions and optical waveguide materials. For example, in addition to rare earth ions such as erbium, ytterbium, and thulium ions, other element ions with large atomic masses can also be implanted. Furthermore, other materials with low transmission loss, such as aluminum nitride and silicon oxynitride, can also be selected as optical waveguide materials. This embodiment is merely an illustrative example.

[0067] First, to effectively illustrate the relationship between implantation depth and implantation energy in rare-earth ion implantation, this application also presents the implantation concentration distribution of erbium ions in silicon nitride waveguides at different implantation energies, such as... Figure 5 As shown, Figure 5 This application provides a schematic diagram showing the relationship between implantation depth and implantation energy, where the horizontal axis represents the implanted erbium ion Er. 3+ The vertical axis represents the implantation depth of erbium ions in the silicon nitride waveguide. The figure clearly shows that the erbium ion distribution in the silicon nitride waveguide exhibits a Gaussian pattern, and the implantation depth increases with increasing implantation energy. For conventional ion implanters, the implantation depth does not exceed 300 nm. For the most widely used ion implanters in the industrial field, with a maximum current implantation energy of 500 keV, the implantation depth will be less than 200 nm.

[0068] In addition, such as Figure 6 and Figure 7 As shown, Figure 6 This application provides a schematic diagram of the fundamental transverse magnetic mode optical field distribution in an erbium-doped silicon nitride waveguide with a thickness of 700 nm. Figure 7 This application provides a schematic diagram of the fundamental transverse magnetic mode optical field distribution in a 200nm thick erbium-doped silicon nitride waveguide, where the fundamental transverse magnetic mode is the TM00 mode. The width of the erbium-doped silicon nitride waveguide is 6000nm. It can be seen that for erbium-doped silicon nitride waveguides in the 1550nm band, if the thickness of the erbium-doped silicon nitride waveguide reaches 700nm, the energy proportion of the fundamental transverse magnetic mode within the waveguide can reach 95.8%, meaning almost all the optical field energy is confined inside the waveguide. However, when the thickness of the erbium-doped silicon nitride waveguide is 200nm, the energy proportion of the fundamental transverse magnetic mode within the waveguide drops to 58.6%, with approximately 40% of the optical field energy leaking into the surrounding material, resulting in significant energy loss.

[0069] Therefore, the preparation process may include: Figure 8 As shown, Figure 8This application provides a schematic flowchart for fabricating a target erbium-doped silicon nitride waveguide. Specifically, a silicon nitride thin film of a predetermined thickness can be grown on a cleaned and polished silicon dioxide silicon wafer using low-pressure vapor deposition or similar methods. Then, erbium ions are implanted into the silicon nitride thin film using a conventional ion implantation device with an ion implantation energy of 500 keV, resulting in the current thin film after rare-earth ion implantation. The current thin film after ion implantation is the erbium-doped silicon nitride thin film.

[0070] Based on the current thin film after ion implantation, the following steps can be repeated: "Using thin film manufacturing processes, a silicon nitride thin film of a predetermined thickness is grown on a cleaned and polished silicon dioxide wafer using low-pressure vapor deposition, followed by ion implantation using a conventional ion implantation device with an ion implantation energy of 500 keV to implant erbium ions into the silicon nitride thin film, resulting in the current ion-implanted thin film." This process can be repeated three times to achieve an erbium ion implantation thickness of approximately 650 nm in the silicon nitride thin film. The preset number of cycles for the deposition-implantation dynamic cycle process is four. The preset thickness of the silicon nitride thin film grown in the first cycle is 200 nm, and the preset thickness of the silicon nitride thin films grown in the subsequent three cycles is 150 nm each. It should be noted that, because the peak concentration of implanted erbium ions is approximately 120 nm under the 500 keV implantation energy condition, the thickness of the subsequent silicon nitride thin films is controlled to be around 150 nm to obtain a relatively flat erbium ion distribution.

[0071] Next, the target silicon nitride film implanted with erbium ions can be annealed at 1000°C in nitrogen for 1 hour, followed by photolithography and etching processes to fabricate the current on-chip gain waveguide; wherein, the current on-chip gain waveguide is the current erbium-doped silicon nitride waveguide. Specifically, the annealing process can activate the implanted erbium ions and repair lattice defects caused by erbium ion implantation after annealing the target silicon nitride film implanted with erbium ions at 1000°C in nitrogen for 1 hour. Then, the photolithography process is performed to transfer the designed waveguide structure and stress relief structure from the mask to the photoresist-coated wafer, and the exposed wafer is developed using a developer to remove or retain the photoresist that has undergone photochemical reactions after exposure. Finally, the etching process is performed to etch away the silicon nitride material that needs to be removed, completing the fabrication of the silicon nitride waveguide structure and stress relief structure.

[0072] Next, the current erbium-doped silicon nitride waveguide can be stripped and cleaned before a silicon dioxide capping layer is deposited to fabricate the target on-chip gain waveguide. Specifically, the target on-chip gain waveguide is the target erbium-doped silicon nitride waveguide. The stripping and cleaning process removes residual photoresist and other impurities, and then a silicon dioxide capping layer is deposited on the fabricated erbium-doped silicon nitride waveguide structure to protect it.

[0073] This application proposes an on-chip gain waveguide fabrication method based on a deposition-implantation dynamic cyclic process. The method includes: growing an optical waveguide material film of a predetermined thickness on a cleaned and polished substrate using a thin film fabrication process; then implanting ions into the newly grown optical waveguide material film using a conventional ion implantation device to obtain the current film after ion implantation. The predetermined thickness is less than the predetermined total film growth thickness, and the current ion implantation energy of the conventional ion implantation device is less than one megaelectron volt. The above steps are repeated for a predetermined number of cycles corresponding to the deposition-implantation dynamic cyclic process until the target ion implantation depth is reached to obtain the target film after ion implantation. The target film after ion implantation is then subjected to annealing, photolithography, and etching processes to prepare the current on-chip gain waveguide. Finally, the current on-chip gain waveguide is subjected to a stripping and cleaning process, followed by deposition of a capping layer to prepare the target on-chip gain waveguide. This approach combines thin film growth with conventional ion implantation equipment to achieve high-depth ion implantation, overcoming the dependence of ion implantation on high-energy ion implantation equipment, reducing equipment requirements and production costs, and facilitating large-scale production. Furthermore, by sequentially performing annealing, photolithography, and etching processes, the fabrication process is simplified while effectively mitigating waveguide deformation caused by high-throughput ion implantation and thin film shrinkage effects from high-temperature annealing. This improves the waveguide structure morphology quality and reduces light dissipation.

[0074] This application also provides an on-chip gain waveguide, which is fabricated according to the above-described on-chip gain waveguide fabrication method based on a deposition-injection dynamic cycle process. Specific implementation processes and beneficial effects can be found in the above-described method embodiments, and will not be repeated here.

[0075] It is readily understood that, based on the several embodiments provided in this application, those skilled in the art can combine, split, or reorganize the embodiments of this application to obtain other embodiments, none of which exceed the protection scope of this application.

[0076] The above detailed embodiments further illustrate the purpose, technical solution, and beneficial effects of the embodiments of this application. It should be understood that the above are merely specific embodiments of the embodiments of this application and are not intended to limit the protection scope of the embodiments of this application. Any modifications, equivalent substitutions, improvements, etc., made on the basis of the technical solutions of the embodiments of this application should be included within the protection scope of the embodiments of this application.

Claims

1. A method for fabricating on-chip gain waveguides based on a deposition-injection dynamic cyclic process, characterized in that, The method includes: A thin film of optical waveguide material of a predetermined thickness is grown on a cleaned and polished substrate using a thin film manufacturing process. Then, ions to be implanted are implanted into the newly grown optical waveguide material film using a conventional ion implantation device to obtain the current film after ion implantation. The predetermined thickness is less than the predetermined total film growth thickness, and the current ion implantation energy of the conventional ion implantation device is less than one megaelectron volt. The above steps are repeated for a preset number of cycles corresponding to the deposition-implantation dynamic cycle process until the target ion implantation depth is reached to obtain the target thin film after ion implantation; wherein, the target ion implantation depth is the same as the preset total thin film growth thickness, and the preset number of cycles is determined based on the preset thickness and the preset total thin film growth thickness; the deposition-implantation dynamic cycle process includes the thin film production process and the ion implantation process, and the thin film production process and the ion implantation process are performed alternately; The target thin film after ion implantation is sequentially subjected to annealing, photolithography and etching processes to prepare the current on-chip gain waveguide. After stripping and cleaning the current on-chip gain waveguide, a capping layer is deposited to prepare the target on-chip gain waveguide.

2. The method according to claim 1, characterized in that, The preset thickness is determined based on the material of the optical waveguide thin film, the ions to be implanted, and the current ion implantation energy.

3. The method according to claim 1, characterized in that, During the deposition-injection dynamic cycle process, the preset thickness of the optical waveguide material film grown in the first stage is the largest.

4. The method according to claim 1, characterized in that, The process of implanting ions into the newly grown optical waveguide material film using conventional ion implantation equipment to obtain the current film after ion implantation includes: A multi-step ion implantation process is used to implant ions into the newly grown optical waveguide material film to obtain the current film after ion implantation; wherein, the current ion implantation energy in the multi-step ion implantation process can be adjusted.

5. The method according to any one of claims 1-4, characterized in that, The target thin film after ion implantation is sequentially subjected to annealing, photolithography, and etching processes to prepare the current on-chip gain waveguide, including: The target film after ion implantation is first subjected to an annealing process to repair lattice defects and activate the implanted ions, resulting in an annealed target film. Then, a photolithography process is performed to transfer the pre-designed waveguide structure and stress relief structure from the preset mask onto the annealed target film, thereby obtaining the photolithographic target film. Finally, an etching process is performed to fabricate the waveguide structure and the stress relief structure on the photolithographic target thin film, thereby obtaining the current on-chip gain waveguide.

6. The method according to any one of claims 1-4, characterized in that, The substrate is a silicon wafer made of silicon dioxide, the optical waveguide material film is a silicon nitride film, and the ions to be implanted are erbium ions. The process involves growing an optical waveguide material film of a predetermined thickness on a cleaned and polished substrate, and then implanting the ions to be implanted into the optical waveguide material film using a conventional ion implantation device to obtain the current film after ion implantation, including: A silicon nitride thin film of a predetermined thickness is grown on a silicon wafer containing cleaned and polished silicon dioxide. Erbium ions are then implanted into the silicon nitride thin film using a conventional ion implantation device with an ion implantation energy of 500 keV to obtain the current thin film after ion implantation. The current thin film after ion implantation is the current silicon nitride thin film implanted with erbium ions.

7. The method according to claim 6, characterized in that, The preset number of cycles for the deposition-implantation dynamic cycling process is four. The preset thickness of the silicon nitride film grown in the first cycle is 200 nm, and the preset thickness of the silicon nitride film grown in the subsequent three cycles is 150 nm.

8. The method according to claim 6, characterized in that, The target thin film after ion implantation is a target silicon nitride thin film implanted with erbium ions. The target thin film after ion implantation is subjected to annealing, photolithography, and etching processes in sequence to prepare the current on-chip gain waveguide, including: The target silicon nitride thin film implanted with erbium ions is annealed at 1000°C in nitrogen for 1 hour, followed by photolithography and etching processes to prepare the current on-chip gain waveguide; wherein, the current on-chip gain waveguide is the current erbium-doped silicon nitride waveguide.

9. The method according to claim 8, characterized in that, The process of stripping and cleaning the current on-chip gain waveguide followed by depositing a capping layer to prepare the target on-chip gain waveguide includes: After stripping and cleaning the current erbium-doped silicon nitride waveguide, a silicon dioxide capping layer is deposited to prepare the target on-chip gain waveguide; wherein, the target on-chip gain waveguide is the target erbium-doped silicon nitride waveguide.

10. An on-chip gain waveguide, characterized in that, The on-chip gain waveguide is fabricated using the on-chip gain waveguide fabrication method based on the deposition-injection dynamic cycle process according to any one of claims 1-9.

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