Low-temperature compensation repair method for phosphorus vacancies after grating dry etching of inp-based dff laser

Abstract

The application relates to a low-temperature compensation repair method for phosphorus vacancies after InP-based DFB laser grating dry etching, which comprises the following steps: (1) completing dry etching of the InP-based DFB laser grating on the surface of an InP-based epitaxial wafer and removing residual photoresist; (2) placing the etched sample in a vacuumized MOCVD reaction chamber, and heating to 400-550 DEG C under the atmosphere of a protective gas; (3) after reaching a preset phosphorus compensation processing temperature and being stabilized, introducing tert-butyl phosphine gas into the reaction chamber and maintaining for 1-30 minutes, so that active phosphorus species released by TBP cracking fills the phosphorus vacancies on the etched surface; (4) directly performing secondary epitaxial buried growth in the MOCVD reaction chamber after completing phosphorus compensation. The device utilizes the characteristics that tert-butyl phosphine can be effectively cracked and active phosphorus sources can be provided under low-temperature conditions, performs low-temperature phosphorus compensation heat treatment on the etched grating sample in the MOCVD reaction chamber, makes active phosphorus atoms released by TBP cracking diffuse into the phosphorus vacancy sites on the etched surface, and repairs the lattice damage caused by dry etching.

Description

Technical Field

[0001] This invention relates to a low-temperature compensation and repair method for phosphorus vacancies after dry etching of the grating in an InP-based DFB laser. Background Technology

[0002] InP-based DFB semiconductor lasers are core optoelectronic devices for realizing 1.55μm band laser emission in fiber optic communication systems. The key lies in fabricating periodic Bragg gratings within the laser's epitaxial structure. Grating fabrication typically employs holographic exposure or electron beam lithography to form a photoresist pattern on the InP capping layer. This pattern is then transferred to the InP material and the grating layer material through etching. After grating etching, buried growth (i.e., secondary epitaxy) is performed to continue growing InP cladding and other structures above the grating.

[0003] Dry etching (including ion etching (RIE), inductively coupled plasma etching (ICP), etc.) has become a common method for fabricating InP-based gratings due to its excellent anisotropy, precise pattern transfer capability, and ability to fabricate high aspect ratio, steep sidewall grating structures. Common dry etching gas systems include CH4 / H2 / Ar and Cl2 / Ar systems.

[0004] In the existing technology, the common fabrication process of InP-based DFB laser gratings is as follows: (1) Perform epitaxial growth on an InP substrate, growing a buffer layer, a lower cladding layer, a multi-quantum-well active layer, an upper cladding layer, a grating layer, and a capping layer in sequence; (2) Form a photoresist grating pattern on the surface of the grating layer by holographic exposure or electron beam lithography; (3) Send the sample into an ICP or RIE device, introduce a CH4 / H2 / Ar (or Cl2 / Ar) mixed gas, and perform dry etching on the exposed InP capping layer and grating layer in a plasma environment to transfer the photoresist pattern into the grating structure and form a periodic grating structure; (4) Remove the residual photoresist; (5) Send the etched sample back into an MOCVD device for secondary epitaxy (buried growth), growing a p-type InP cladding layer, a p-type contact layer, etc. in sequence on the grating structure to complete the fabrication of the laser epitaxial structure. The above-mentioned existing technology has the following technical defects in practical applications: (1) Phosphorus vacancy damage caused by dry etching: During dry etching of InP in the CH4 / H2 / Ar or Cl2 / Ar system, preferential desorption or sputtering of phosphorus atoms occurs due to the difference in physicochemical properties between In and P atoms. Studies have shown that in CH4 / H2 / Ar etching, preferential desorption of P atoms produces droplet-like residues; under Ar ion beam bombardment, P atoms are preferentially sputtered, forming an indium-rich surface; in Cl2 / Ar etching, the high volatility of P chloride makes it easy to remove, while the low volatility of In chloride makes it easy to remain, further exacerbating the imbalance of surface stoichiometry. The above effects together lead to the absence of P atoms at the etching interface, forming an indium-rich damage layer with a thickness of about 10-40 Å. This damage layer disrupts the periodic structure of the InP lattice, introducing a large number of phosphorus vacancies on the grating surface and sidewalls.

[0005] (2) The serious impact of phosphorus vacancies on the quality of buried growth: If the phosphorus vacancy-damaged layer is not treated before secondary epitaxial buried growth, a series of problems will occur. First, the indium-rich surface reduces the nucleation quality of the subsequent epitaxial layer, resulting in crystal defects such as dislocations and microtwins in the buried layer; second, as a non-radiative recombination center, phosphorus vacancies will significantly reduce the luminous efficiency of the laser; third, the damaged layer may also introduce interface states, affecting the carrier injection efficiency and the reliability of the device.

[0006] (3) Limitations of existing repair methods: To address the above problems, existing technologies have attempted to remove the damaged layer using wet chemical etching (e.g., mild etching with diluted HCl solution). However, this method has the following problems: wet etching is isotropic and can over-etch the fine structure of the grating, leading to grating morphology degradation, duty cycle changes, and grating depth reduction, thereby affecting the mode selection properties and coupling efficiency of the DFB laser. Some studies have also attempted to repair the damage by high-temperature annealing in a phosphorus atmosphere. However, high-temperature annealing itself may cause further thermal decomposition of InP and the grating layer material, and requires specialized annealing equipment and a phosphorus source supply system, increasing the complexity and cost of the process. Summary of the Invention

[0007] This invention addresses the aforementioned problem by providing a low-temperature compensation and repair method for phosphorus vacancies in InP-based DFB laser gratings after dry etching. Specifically, it provides a method that effectively repairs phosphorus vacancies at the etching interface, restores surface stoichiometry, and does not damage the fine morphology of the grating, after dry etching and before buried growth of the InP-based DFB laser grating. This improves the crystal quality of the secondary epitaxial buried growth and ultimately enhances the photoelectric performance and reliability of the DFB laser.

[0008] The present invention is constructed as follows, comprising the following steps: (1) Dry etching of the InP-based DFB laser grating on the surface of the InP-based epitaxial wafer to remove residual photoresist; (2) Placing the etched sample in a vacuum-sealed MOCVD reaction chamber and heating it to 400-550°C under a protective gas atmosphere; (3) After reaching the preset phosphorus compensation treatment temperature and stabilizing, introducing tert-butylphosphine (TBP) gas into the reaction chamber and maintaining it for 1-30 minutes, so that the active phosphorus species released by TBP decomposition fill the phosphorus vacancies on the etched surface; (4) After completing phosphorus compensation, performing secondary epitaxial buried growth directly in the MOCVD reaction chamber.

[0009] Furthermore, in step (2), the protective gas is H2 or N2.

[0010] Furthermore, in step (3), the carrier gas of TBP is high-purity H2, the TBP flow rate is 50-500 sccm, and the MOCVD reaction chamber pressure is controlled at 50-500 Torr.

[0011] Furthermore, in step (3), TBP is partially cleaved at 400-550°C, and the resulting active phosphorus species include at least one of PH2 and PH, which react with excess In atoms on the etched surface to form In-P chemical bonds.

[0012] Furthermore, in step (1), on the InP wafer after one epitaxial growth, a photoresist grating pattern is formed on the surface of the grating layer by holographic exposure or electron beam lithography; the sample is placed in an ICP etching apparatus, and a CH4 / H2 / Ar mixed gas or a Cl2 / Ar mixed gas is introduced. Dry etching is performed under appropriate RF power and chamber pressure conditions to transfer the grating pattern into the InP-based grating layer; after etching is completed, the residual photoresist masking layer is removed.

[0013] Furthermore, after step (1) and before step (2), the surface of the grating after dry etching is pretreated. After the photoresist is removed, a light wet cleaning can be selectively performed to remove surface contaminants that may be generated during the etching process. However, long-term wet etching should be avoided to maintain the grating morphology.

[0014] Furthermore, in step (4), after completing the phosphorus compensation heat treatment, the reaction chamber can be selectively purged to remove residual gas and byproducts; then the temperature of the reaction chamber is adjusted to the normal temperature for InP buried growth, which is 550-700°C, and an In source and a TBP growth source are introduced to perform secondary epitaxial buried growth of materials such as p-type InP cladding on the repaired grating structure.

[0015] Furthermore, the In source is trimethylindium™In, and the TBP growth source can also be PH3.

[0016] Furthermore, in step (3), during the phosphorus compensation treatment, the optimal phosphorus compensation treatment time is determined by in-situ monitoring or by offline testing.

[0017] Compared with the prior art, the present invention has the following beneficial effects: (1) Effective repair of phosphorus vacancy damage and restoration of surface stoichiometry: Through low-temperature TBP phosphorus compensation heat treatment, active phosphorus atoms can diffuse into the phosphorus vacancy sites on the etched surface and react with the indium-rich surface to form In-P bonds, restoring the surface stoichiometry to a state close to the ideal state of InP, fundamentally solving the phosphorus vacancy problem introduced by dry etching. Compared with the existing technology that relies solely on wet etching to remove the damaged layer, the compensation and repair scheme of this invention is "filling" rather than "removing", without losing grating material.

[0018] (2) Maintaining the fine morphology of the grating without damaging the micro / nano structure: The wet chemical etching in the prior art has isotropic characteristics, which will over-etch the sidewalls and top of the grating, resulting in grating morphology degradation, duty cycle changes and depth reduction. The low-temperature TBP phosphorus compensation heat treatment of the present invention is a surface reaction process carried out in a gas phase environment, which does not involve liquid phase corrosion. Therefore, it will not damage the fine morphology of the grating, and can maintain the key parameters such as the period, duty cycle and depth of the grating unchanged, which is beneficial to the mode selection stability of the DFB laser.

[0019] (3) Good process compatibility and can be integrated in situ with MOCVD epitaxy: The phosphorus compensation heat treatment of the present invention can be completed using existing MOCVD equipment without the need to purchase an additional annealing furnace or phosphorus atmosphere protection device. This treatment can be carried out in situ before secondary epitaxial buried growth, or even during the heating stage, without increasing additional equipment investment and production cycle, and is highly compatible with the existing InP-based DFB laser manufacturing process.

[0020] (4) Improved crystal quality of secondary epitaxial buried growth: Due to the correct stoichiometry and fewer lattice defects on the grating surface after phosphorus compensation repair, the nucleation quality of secondary epitaxial buried growth is significantly improved. The density of crystal defects such as dislocations and microtwins in the buried InP layer is reduced, and the interface between the grating and the buried layer is clearer and smoother, thereby reducing non-radiative recombination centers and improving the luminous efficiency and reliability of DFB lasers.

[0021] (5) Reduce the thermal budget and avoid secondary damage caused by high-temperature annealing: The high-temperature phosphorus atmosphere annealing used in the prior art usually needs to be carried out at a temperature above 600°C. Prolonged heating may cause further thermal decomposition and impurity diffusion of InP materials and grating materials. The present invention utilizes the low-temperature pyrolysis characteristics of TBP to control the phosphorus compensation treatment temperature at 400-550°C, which significantly reduces the thermal budget and avoids the adverse effects that high-temperature treatment may cause.

[0022] (6) Improve the photoelectric performance and yield of DFB lasers: Through the above comprehensive advantages, the InP-based DFB lasers prepared by the method of the present invention are superior to those prepared by existing technologies in terms of threshold current, slope efficiency, side-mode suppression ratio and high-temperature reliability. At the same time, it reduces device failures caused by buried layer quality problems, which helps to improve the product yield. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the process flow of an embodiment of the present invention; Figure 2 This is a schematic diagram illustrating the TBP low-temperature phosphorus compensation and repair principle in an embodiment of the present invention. Detailed Implementation

[0024] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0025] Example 1: As Figure 1-2 As shown in this embodiment, a low-temperature compensation repair method for phosphorus vacancies after dry etching of an InP-based DFB laser grating is provided, including the following steps: (1) Dry etching of the InP-based DFB laser grating is performed on the surface of the InP-based epitaxial wafer to remove residual photoresist; (2) The etched sample is placed in a vacuum-sealed MOCVD reaction chamber and heated to 400-550°C under a protective gas atmosphere; (3) After reaching the preset temperature and stabilizing, tert-butylphosphine (TBP) gas is introduced into the reaction chamber and maintained for 1-30 minutes to allow the active phosphorus species released by TBP decomposition to fill the phosphorus vacancies on the etched surface; (4) After completing the phosphorus compensation, secondary epitaxial buried growth is performed directly in the MOCVD reaction chamber.

[0026] In this embodiment of the invention, TBP is an organometallic phosphorus source with the molecular formula (CH3)3CPH2. Studies have shown that the thermal decomposition initiation temperature of TBP in a hydrogen environment is approximately 500°C (773K), and the decomposition products include isobutylene, phosphine, and isobutane. Decomposition tends to be complete above 700°C (973K). Compared to the conventional phosphorus source PH3, TBP decomposes at a lower temperature and provides active phosphorus atoms. Further studies show that the adhesion probability of TBP on the InP surface decreases with increasing temperature from 0.007 at 420°C to 0.001 at 520°C, indicating that TBP has better surface adsorption and decomposition efficiency in the lower temperature range. Studies have shown that rapid thermal annealing of InP substrates in a TBP atmosphere can obtain a damage-free surface at temperatures up to 700°C.

[0027] The low-temperature phosphorus compensation repair of this invention utilizes this characteristic of TBP: in the low-temperature range of 400-550°C, TBP is adsorbed and partially decomposed on the InP surface, releasing active phosphorus atoms or phosphorus-containing groups (such as PH2, PH, etc.). These active phosphorus species can diffuse into the phosphorus vacancy sites on the etched surface, react with the indium-rich surface, reform In-P chemical bonds, repair the lattice damage caused by the absence of P atoms, and restore the surface stoichiometry to a state close to the ideal InP ratio.

[0028] The advantages of this invention are as follows: (1) Using the low-temperature pyrolysis characteristics of TBP to repair phosphorus vacancies: For the first time, it is proposed that after dry etching of the InP-based DFB laser grating and before buried growth, the phosphorus compensation heat treatment of the etched surface can be carried out by utilizing the characteristic that TBP can effectively pyrolyze and release active phosphorus at a low temperature of 400-550°C to repair the surface lattice damage caused by the absence of P atoms.

[0029] (2) Temperature window for phosphorus compensation treatment: The temperature of phosphorus compensation treatment is limited to 400-550°C. This temperature range ensures the full decomposition of TBP and the effective supply of phosphorus, while avoiding the thermal decomposition of InP and grating materials and the degradation of grating morphology that may be caused by high temperature treatment.

[0030] (3) In-situ integration of phosphorus compensation treatment and buried growth: The low-temperature TBP phosphorus compensation heat treatment and secondary epitaxial buried growth are continuously completed in the same MOCVD reaction chamber, or phosphorus compensation is achieved in-situ during the heating process of buried growth, without the need for additional annealing equipment, thus simplifying the process.

[0031] (4) Application of TBP as a phosphorus compensation source: TBP is used as an active phosphorus source for phosphorus compensation and repair. Taking advantage of its lower pyrolysis temperature than PH3 and suitable surface adhesion characteristics, it can achieve efficient phosphorus vacancy filling at low temperature.

[0032] (5) Repair method for phosphorus vacancy damage of dry etching InP-based gratings: For phosphorus vacancy damage layers generated after dry etching of InP-based gratings in CH4 / H2 / Ar system and Cl2 / Ar system, a non-destructive repair scheme that maintains the fine morphology of the grating is provided.

[0033] In this embodiment of the invention, in step (2), the protective gas is H2 or N2.

[0034] In this embodiment of the invention, in step (3), the carrier gas of TBP is high-purity H2, the TBP flow rate is 50-500 sccm, and the MOCVD reaction chamber pressure is controlled at 50-500 Torr.

[0035] In this embodiment of the invention, in step (3), TBP is partially decomposed at 400-550°C, and the resulting active phosphorus species include at least one of PH2 and PH, which react with the excess In atoms on the etched surface to generate In-P chemical bonds.

[0036] In this embodiment of the invention, in step (1), a photoresist grating pattern is formed on the surface of the grating layer by holographic exposure or electron beam lithography on the InP wafer after one epitaxial growth is completed; the sample is placed in an ICP etching apparatus, and a CH4 / H2 / Ar mixed gas or a Cl2 / Ar mixed gas is introduced. Dry etching is performed under appropriate radio frequency power and chamber pressure conditions to transfer the grating pattern into the InP-based grating layer; after etching is completed, the residual photoresist masking layer is removed.

[0037] In this embodiment of the invention, after step (1) and before step (2), the surface of the grating after dry etching is pretreated. After the photoresist is removed, a light wet cleaning can be selectively performed to remove surface contaminants that may be generated during the etching process. However, long-term wet etching should be avoided to maintain the grating morphology.

[0038] In this embodiment of the invention, in step (4), after completing the phosphorus compensation heat treatment, the reaction chamber can be selectively purged to remove residual gas and byproducts; then the temperature of the reaction chamber is adjusted to the normal temperature for InP buried growth, which is 550-700°C, and an In source and a TBP growth source are introduced to perform secondary epitaxial buried growth of materials such as p-type InP cladding on the repaired grating structure.

[0039] The In source is trimethylindium™In, and the TBP growth source can also be PH3.

[0040] In this embodiment of the invention, in step (3), during the phosphorus compensation treatment, the optimal phosphorus compensation treatment time is determined by in-situ monitoring or by offline testing.

[0041] In-situ monitoring methods can include reflectance monitoring, while offline testing can include methods such as XPS and PL.

[0042] Example 2: Based on Example 1, the specific working steps in this embodiment of the invention are as follows: Step 1: Dry etching of InP-based DFB laser grating On an InP wafer after epitaxy, a photoresist grating pattern is formed on the surface of the grating layer by holographic exposure or electron beam lithography. The sample is placed in an ICP etching apparatus, and a CH4 / H2 / Ar mixed gas (or Cl2 / Ar mixed gas) is introduced. Dry etching is performed under appropriate RF power and chamber pressure conditions to transfer the grating pattern into the InP-based grating layer. After etching, the residual photoresist masking layer is removed.

[0043] During the aforementioned dry etching process, due to the aforementioned mechanisms such as preferential desorption, preferential sputtering, and differences in chloride volatility, phosphorus vacancy damage layers inevitably form on the etched surface and sidewalls of the InP-based grating, resulting in an excess of In atoms on the surface and the formation of an indium-rich surface with a non-stoichiometric ratio.

[0044] Step 2: Pretreatment of the grating surface after dry etching After the photoresist is removed, a light wet cleaning can be selectively performed to remove surface contaminants that may have been generated during the etching process, but prolonged wet etching should be avoided to maintain the grating morphology.

[0045] Step 3: Low-temperature TBP phosphorus-compensated heat treatment The dry-etched sample is immediately transferred to the MOCVD reaction chamber (or after being stored in a clean environment); after the reaction chamber is evacuated, it is heated to the preset phosphorus compensation treatment temperature under a protective gas atmosphere (preferably H2 or N2), such as... Figure 2 As shown.

[0046] The preferred phosphorus compensation treatment temperature is 400-550°C. Within this temperature range, TBP has the following advantages: (1) TBP begins to undergo thermal decomposition, generating sufficient active phosphorus species to fill phosphorus vacancies; (2) The temperature is lower than the significant thermal decomposition temperature of InP, which can avoid further thermal decomposition of InP substrate and grating structure; (3) The surface adhesion probability of TBP is relatively high in this temperature range, which is conducive to the effective deposition and diffusion of phosphorus.

[0047] After the preset temperature is reached and stabilized, TBP gas is introduced into the MOCVD reaction chamber. The preferred carrier gas for TBP is high-purity H2, and the preferred TBP flow rate is 50-500 sccm (adjustable according to the reaction chamber volume and sample size). The reaction chamber pressure is preferably controlled between 50-500 Torr.

[0048] After TBP gas enters the reaction chamber, it undergoes adsorption and partial decomposition on the heated grating surface. TBP molecules bind to exposed In atoms on the surface through coordination bonds, followed by dehydrogenation and detert-butylation reactions, releasing reactive phosphorus-containing species such as PH2 or PH. These reactive phosphorus species have high migration and reactivity, and can diffuse into phosphorus vacancies on the grating surface, forming In-P chemical bonds with excess In atoms, gradually restoring the stoichiometry of InP and lattice integrity on the surface.

[0049] The optimal duration of phosphorus compensation treatment is 1-30 minutes. Too short a treatment time may result in insufficient phosphorus compensation, while too long a treatment time may cause unnecessary surface roughening or byproduct accumulation. The optimal treatment time can be determined through in-situ monitoring (such as reflectivity monitoring) or offline testing (such as XPS, PL).

[0050] Step 4: Secondary epitaxial growth After completing the phosphorus-compensated heat treatment, the reaction chamber can be selectively purged to remove residual gases and byproducts. Subsequently, the reaction chamber temperature is adjusted to the conventional temperature for InP buried growth (usually 550-700°C), and growth sources such as In (e.g., trimethylindium™In) and TBP (or PH3) are introduced to perform secondary epitaxial buried growth of materials such as p-type InP cladding on the repaired grating structure.

[0051] Since the low-temperature phosphorus compensation treatment in step three has effectively repaired the phosphorus vacancy damage caused by dry etching, the stoichiometry of the etched surface has been restored to near-ideal state. Therefore, the nucleation quality of secondary epitaxial growth is significantly improved, the crystal defect density in the buried layer is reduced, and the interface quality between the grating and the buried layer is improved, which is conducive to improving the optoelectronic performance of the DFB laser.

[0052] Unless otherwise stated, if any of the technical solutions disclosed in this invention specify a numerical range, then the disclosed numerical range is a preferred numerical range. Anyone skilled in the art should understand that the preferred numerical range is merely one among many feasible numerical values ​​that has a more obvious or representative technical effect. Because there are many numerical values, it is impossible to list them all. Therefore, this invention discloses only some numerical values ​​to illustrate the technical solutions of this invention. Furthermore, the numerical values ​​listed above should not constitute a limitation on the scope of protection of this invention.

[0053] Furthermore, if the present invention discloses or relates to mutually fixedly connected components or structural parts, then unless otherwise stated, a fixed connection can be understood as: a detachable fixed connection (e.g., using bolts or screws), or a non-detachable fixed connection (e.g., riveting, welding). Of course, mutually fixed connections can also be replaced by an integral structure (e.g., manufactured using a casting process) (except where it is obviously impossible to use an integral molding process).

[0054] In addition, unless otherwise stated, the terms used in any of the technical solutions disclosed in this invention to indicate positional relationships or shapes include states or shapes that are similar to, close to, or approximate with those states or shapes.

[0055] Any component provided by this invention can be assembled from multiple individual components or can be a single component manufactured by a one-piece molding process.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of the present invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. A low-temperature compensation and repair method for phosphorus vacancies after dry etching of the grating in an InP-based DFB laser, characterized in that, Includes the following steps: (1) Dry etching of the InP-based DFB laser grating is performed on the surface of the InP-based epitaxial wafer to remove residual photoresist; (2) The etched sample is placed in a vacuum-sealed MOCVD reaction chamber and heated to 400-550°C under a protective gas atmosphere; (3) After reaching the preset phosphorus compensation treatment temperature and stabilizing, tert-butylphosphine (TBP) gas is introduced into the reaction chamber and maintained for 1-30 minutes to allow the active phosphorus species released by TBP decomposition to fill the phosphorus vacancies on the etched surface; (4) After completing phosphorus compensation, secondary epitaxial buried growth is performed directly in the MOCVD reaction chamber.

2. The low-temperature compensation and repair method for phosphorus vacancies after dry etching of the grating in an InP-based DFB laser according to claim 1, characterized in that, In step (2), the protective gas is H2 or N2.

3. The low-temperature compensation and repair method for phosphorus vacancies after dry etching of the grating in an InP-based DFB laser according to claim 1, characterized in that, In step (3), the carrier gas of TBP is high-purity H2, the TBP flow rate is 50-500 sccm, and the MOCVD reaction chamber pressure is controlled at 50-500 Torr.

4. The low-temperature compensation and repair method for phosphorus vacancies after dry etching of the grating in an InP-based DFB laser according to claim 1, characterized in that, In step (3), TBP is partially pyrolyzed at 400-550°C, and the resulting active phosphorus species include at least one of PH2 and PH, which react with excess In atoms on the etched surface to form In-P chemical bonds.

5. The low-temperature compensation and repair method for phosphorus vacancies after dry etching of the grating in an InP-based DFB laser according to claim 1, characterized in that, In step (1), a photoresist grating pattern is formed on the surface of the grating layer by holographic exposure or electron beam lithography on the InP wafer after one epitaxial growth is completed; the sample is placed in an ICP etching device, and a CH4 / H2 / Ar mixed gas or a Cl2 / Ar mixed gas is introduced. Dry etching is performed under appropriate radio frequency power and chamber pressure conditions to transfer the grating pattern into the InP-based grating layer. After etching is complete, remove the remaining photoresist masking layer.

6. The low-temperature compensation and repair method for phosphorus vacancies after dry etching of the grating in an InP-based DFB laser according to claim 1, characterized in that, After step (1) and before step (2), the surface of the grating after dry etching is pretreated. After the photoresist is removed, a light wet cleaning can be selectively performed to remove surface contaminants that may be generated during the etching process. However, long-term wet etching should be avoided to maintain the grating morphology.

7. A low-temperature compensation and repair method for phosphorus vacancies after dry etching of an InP-based DFB laser grating, as described in claim 1, is characterized in that... In step (4), after completing the phosphorus compensation heat treatment, the reaction chamber can be selectively purged to remove residual gas and byproducts; then the temperature of the reaction chamber is adjusted to the normal temperature for InP buried growth, which is 550-700°C, and an In source and a TBP growth source are introduced to perform secondary epitaxial buried growth of materials such as p-type InP cladding on the repaired grating structure.

8. A low-temperature compensation and repair method for phosphorus vacancies after dry etching of an InP-based DFB laser grating, as described in claim 7, is characterized in that... The In source is trimethylindium™In, and the TBP growth source can also be PH3.

9. A low-temperature compensation and repair method for phosphorus vacancies after dry etching of an InP-based DFB laser grating, as described in claim 1, characterized in that, In step (3), the optimal phosphorus compensation treatment time is determined by in-situ monitoring or by offline testing during the phosphorus compensation treatment.

Images