A method and apparatus for liquid phase epitaxy growth with dynamic regulation of lattice mismatch

Abstract

The application relates to the technical field of semiconductor material preparation, in particular to a liquid phase epitaxial growth method and equipment for dynamically regulating lattice mismatch. The specific content is as follows: a substrate is pretreated to prepare micro pits and grooves of the substrate, and a uniform solution is prepared according to phase diagram information; a temperature gradient is set in a multi-zone temperature control epitaxial furnace, and the epitaxial growth of the substrate is controlled through a boat device; the substrate and the solution pool are sequentially moved into the furnace; during the epitaxial growth process, the lattice constant error, morphology and photoelectric properties of the growth are detected, and when the detection signal deviates from the predetermined threshold, the lattice mismatch is compensated by adjusting the solution concentration and the temperature; during the displacement process, the mother liquor remaining between different layers is poured into the grooves of the substrate through the inclined substrate. The application solves the problem of lattice mismatch control by real-time detection and real-time regulation of the lattice mismatch, and improves the quality and performance of the epitaxial layer.

Description

Technical Field

[0001] This invention relates to the field of semiconductor material preparation technology, specifically to a liquid phase epitaxial growth method and equipment for dynamic control of lattice mismatch. Background Technology

[0002] Liquid phase epitaxy is an important method for preparing high-quality compound semiconductor materials and is widely used in the manufacture of optoelectronic devices, high-frequency devices, and power devices. This technique can achieve atomically flat epitaxial layer growth at relatively low temperatures, which is of great significance for the preparation of high-performance heterostructures.

[0003] However, existing liquid-phase epitaxy techniques face several challenges in fabricating heterostructures made from materials with different lattice constants. Traditional methods, employing fixed growth parameters, struggle to respond in real-time to changes in lattice mismatch during growth, leading to stress accumulation and the formation of high-density dislocations. Current technologies lack effective real-time monitoring methods, making it difficult to accurately grasp the lattice matching state of the epitaxial layers and to dynamically adjust process parameters for compensation during growth. Furthermore, contamination from residual mother liquor during interlayer switching severely impacts the growth quality of subsequent layers. These technical limitations restrict the fabrication of high-quality heterostructures, affecting the electrical performance and reliability of devices and hindering the development of related industries. Summary of the Invention

[0004] This invention provides a liquid phase epitaxial growth method and equipment for dynamic control of lattice mismatch, which solves the problems of difficulty in controlling lattice mismatch, high dislocation density and poor device performance caused by fixed parameter growth in the prior art, and realizes the stable preparation of high-quality heterostructures.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] A liquid-phase epitaxial growth method with dynamic control of lattice mismatch includes:

[0007] S100: The substrate is pretreated by high-temperature annealing and vapor phase polishing, and a micro-pit structure is formed on the substrate surface by wet etching; under the protection of an inert atmosphere, the ratio of solvent to solute is determined according to the phase diagram data of the target epitaxial layer material, and a homogeneous solution is formed by high-temperature pre-melting.

[0008] S200: An axial temperature gradient is established in a liquid phase epitaxial furnace with independent temperature control in multiple zones, and sequential contact between the substrate and different component solution pools is achieved through a programmable sliding boat system;

[0009] S300: During epitaxial growth, lattice constant deviation, surface morphology and photoelectric performance parameters are monitored in real time. When the monitoring signal deviates from the preset range, the solution component concentration and growth temperature are dynamically and collaboratively adjusted to achieve lattice mismatch compensation.

[0010] S400: During interlayer switching, the substrate is tilted by tilting the substrate structure, and the residual mother liquor is poured into the collection groove by gravity.

[0011] As a preferred technical solution of the present invention, in S100, the substrate pretreatment and micro-pit structure formation includes: high-temperature annealing of the substrate in H2 environment to remove the surface oxide layer, achieving atomic-level clean surface by HCl vapor phase polishing, and then forming hexagonal V-shaped micro-pits on the substrate surface by maskless wet etching process.

[0012] As a preferred technical solution of the present invention, in S100, the process of forming a uniform solution includes: determining the initial ratio of solvent to solute by phase diagram calculation so that the solution is saturated or supersaturated at the initial temperature; accurately weighing high-purity metal raw materials and dopants and mixing them according to the calculation results; pre-melting the raw materials at high temperature under inert gas protection to completely dissolve the raw materials and form a uniform solution; and adjusting the temperature or composition so that the solution reaches a dynamic equilibrium state after contacting the substrate.

[0013] As a preferred embodiment of the present invention, in S200, the establishment of the axial temperature gradient includes:

[0014] The furnace body is divided into three or more temperature control zones using a zoned temperature control method.

[0015] Target temperatures are set for different regions to create an axial temperature gradient;

[0016] Temperature feedback control is used to maintain temperature stability in each area;

[0017] Combined with insulation measures, the uniformity of the temperature field distribution is controlled.

[0018] As a preferred embodiment of the present invention, in S200, the sequential contact between the substrate and the different component solution pools includes:

[0019] The substrate is mounted on a movable carrier;

[0020] The vehicle's speed and dwell time are controlled according to a preset program;

[0021] The contact area between the substrate and the support surface is reduced by using line contact.

[0022] Ensure that the substrate surface is in full contact with the solution pool while maintaining uniform airflow coverage.

[0023] As a preferred embodiment of the present invention, in step S300, the lattice mismatch compensation step includes:

[0024] The difference between the lattice constant of the epitaxial layer and the substrate is monitored in real time by X-ray diffraction. Surface roughness, growth ripples or dislocation density are detected by optical microscopy or scanning electron microscopy. Photoelectric performance parameters are detected by measuring carrier concentration, mobility and emission wavelength.

[0025] When the lattice constant deviation exceeds the set ratio of the substrate lattice constant, a synergistic adjustment mechanism of solution component concentration and growth temperature is adopted to achieve dynamic compensation of lattice mismatch through high temperature-high concentration coupling and thermodynamic compensation effect.

[0026] When the surface roughness exceeds the preset critical value or the dislocation density is abnormal, a step-by-step adjustment mechanism is adopted to first adjust the temperature to optimize the surface mobility and then fine-tune the concentration to repair the lattice distortion.

[0027] When the carrier mobility decreases beyond a preset threshold, growth is paused and in-situ annealing is performed.

[0028] As a preferred embodiment of the present invention, in step S400, the treatment of residual mother liquor between layers includes:

[0029] After each epitaxial layer is grown, the substrate is tilted to a preset angle;

[0030] Control the tilt angle and residence time to ensure that the residual mother liquor flows and is collected fully;

[0031] After completing liquid collection, return the substrate to a horizontal position;

[0032] Move to the next solution tank location for subsequent growth.

[0033] The present invention also includes a liquid phase epitaxy apparatus for dynamic control of lattice mismatch, comprising:

[0034] Preprocessing module: Used to execute the S100 process, including high-temperature annealing equipment, vapor phase polishing equipment, and wet etching equipment;

[0035] Temperature control module: Used to execute the S200 process, including multi-zone independently temperature-controlled liquid phase epitaxial furnace;

[0036] Transmission module: Used to execute the S200 process, including a programmable sliding boat system;

[0037] Monitoring module: Used to execute the S300 process, including X-ray diffraction equipment, optical microscope equipment, and in-situ photoluminescence spectroscopy measurement equipment;

[0038] Control module: Used to execute the S300 process, including solution component adjustment equipment and temperature control equipment;

[0039] Cleaning module: Used to perform the S400 process, including tilted substrate structure and collection groove device.

[0040] The beneficial effects of this invention are:

[0041] 1. This invention breaks through the traditional "open-loop" growth mode of liquid-phase epitaxy and establishes an intelligent closed-loop control mechanism of "monitoring-feedback-execution". By integrating a multi-parameter online monitoring system using X-ray diffraction, optical microscopy, and photoluminescence spectroscopy, it can detect changes in lattice constant deviation, surface morphology, and photoelectric properties in real time. Combined with a synergistic adjustment mechanism of solution component concentration and growth temperature, dynamic compensation is executed immediately when the monitoring signal deviates from the preset range. This technology transforms "post-event detection" into "process control," fundamentally suppressing the generation of dislocation defects and significantly improving the crystal quality and electrical properties of the epitaxial layer.

[0042] 2. This invention organically integrates substrate micropitting, sequential contact of multiple solution pools, collection of residual mother liquor between layers, and a dynamic control system into a complete solution. The V-shaped micropit structure provides optimized oriented nucleation sites, effectively relieving stress; the programmable sliding boat and tilted collection groove design ensure clean interfaces during interlayer switching, avoiding solution mixing; the dynamic control system guarantees high-quality growth for each layer. The synergistic effect of multiple technologies enables high-level fabrication of multilayer structures with clear, steep interfaces and low defects, significantly improving the production yield and performance consistency of complex structure devices. Attached Figure Description

[0043] The accompanying drawings, as part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention, but do not constitute an undue limitation of the invention. Obviously, the drawings described below are merely some embodiments, and those skilled in the art can obtain other drawings based on these drawings without creative effort. In the drawings:

[0044] Figure 1 This is a schematic flowchart of a liquid phase epitaxial growth method for dynamic control of lattice mismatch according to the present invention.

[0045] Figure 2 This is a schematic diagram of the system configuration of a liquid phase epitaxial device for dynamic control of lattice mismatch according to the present invention.

[0046] It should be noted that these accompanying drawings and textual descriptions are not intended to limit the scope of the invention in any way, but rather to illustrate the concept of the invention to those skilled in the art by referring to specific embodiments. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below with reference to the accompanying drawings. The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0048] In the description of this invention, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0049] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0050] Furthermore, 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 technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0051] [Example 1]

[0052] like Figure 1 As shown, the present invention provides a liquid-phase epitaxial growth method for dynamic control of lattice mismatch, comprising:

[0053] S100: The substrate is pretreated by high-temperature annealing and vapor phase polishing, and a micro-pit structure is formed on the substrate surface by wet etching; under the protection of an inert atmosphere, the ratio of solvent to solute is determined according to the phase diagram data of the target epitaxial layer material, and a homogeneous solution is formed by high-temperature pre-melting.

[0054] Furthermore, the pretreatment of the substrate by high-temperature annealing and vapor phase polishing, and the formation of micro-pit structures on the substrate surface by wet etching, includes: high-temperature annealing of the substrate in an H2 environment to remove the surface oxide layer, achieving an atomically clean surface by HCl vapor phase polishing, and then forming hexagonal V-shaped micro-pits on the substrate surface by a maskless wet etching process. The micro-pits have hexagonal geometric features and are arranged periodically.

[0055] Specifically, a c-plane GaN template substrate (polished wafer) is selected. It is ultrasonically cleaned sequentially with anhydrous isopropanol and ultrapure water, dried, and then placed in a quartz support boat, ensuring that the polished surface faces upward and the edge is aligned with the reference edge of the support boat to avoid uneven airflow and temperature field in the subsequent process.

[0056] The carrier boat is pushed into the quartz tube furnace, pressurized and sealed, and then high-purity H2 is introduced for displacement, maintaining continuous flow to remove residual air. The temperature is increased to the process temperature according to the set heating program, and maintained at this temperature for a fixed period to remove the surface oxide layer and adsorbed contaminants. After annealing, H2 is continuously introduced while the temperature is reduced at a set rate to the vapor phase polishing initiation temperature.

[0057] Under a continuously flowing H2 atmosphere, a measured amount of HCl is introduced as a vapor-phase etchant to induce controlled etching on the substrate surface, removing surface micro-protrusions and processing damage layers to obtain an atomically clean and smooth surface. During polishing, furnace pressure and total flow rate are monitored and kept stable. After polishing, the HCl supply is stopped, leaving only H2 to rinse the reaction zone, and then the temperature is lowered at a set rate to the temperature range required for wet etching.

[0058] The substrate was placed in an anti-corrosion treatment tank and gradually immersed in a pre-prepared constant-temperature KOH aqueous solution, ensuring that the polished surface of the substrate was completely covered by the solution and parallel to the liquid surface. By precisely controlling the reaction time and solution agitation frequency, the etching process was promoted to proceed along the anisotropic direction of the GaN crystal, naturally generating a hexagonal V-shaped pit array with periodic distribution characteristics on the substrate surface. After the etching process was completed, a high-flow-rate ultrapure water was used for immediate rinsing, followed by replacement of residual moisture with anhydrous isopropanol and drying with nitrogen gas flow to prevent watermark formation and secondary contamination. Optical microscopy was used to quickly inspect the integrity and uniformity of the micropit structure. After verifying that the continuity of the array structure and the clarity of the boundary contours were up to standard, the sample was stored for later use.

[0059] Furthermore, the step of determining the solvent-to-solute ratio based on the phase diagram data of the target epitaxial layer material and forming a homogeneous solution through high-temperature pre-melting includes: determining the initial ratio of solvent to solute through phase diagram calculation to ensure that the solution is saturated or supersaturated at the initial temperature; accurately weighing high-purity metal raw materials and dopants and mixing them according to the calculation results; completely dissolving the raw materials and forming a homogeneous solution through high-temperature pre-melting under inert gas protection; and achieving a dynamic equilibrium state after the solution comes into contact with the substrate by adjusting the temperature or composition.

[0060] Based on the phase diagram calculation results of the target epitaxial layer material, the initial ratio of solvent to solute required to achieve saturation or slight supersaturation at the initial temperature is determined. High-purity metal solvent, corresponding high-purity solute, and predetermined dopant are precisely weighed using an electronic balance in a clean glove box, placed into a pre-dried high-purity graphite crucible, and a dense graphite cap is placed at the crucible opening to reduce evaporation and external contamination.

[0061] The charging crucible is placed in the solution pool area of ​​the liquid phase epitaxy furnace, and high-purity inert gas is repeatedly introduced for replacement to maintain a stable flow. The temperature is increased to the pre-melting temperature according to the set heating program, and held at this temperature until the solid phase is completely dissolved and the solution becomes bright and uniform. During the holding period, the solution is intermittently stirred at low speed with a quartz stir bar to promote uniform distribution of components and eliminate local concentration gradients.

[0062] The homogeneity of the solution was confirmed by observing whether the surface reflection and surface fluctuation of the solution in the crucible were consistent, and by checking the crystal plane uniformity of the solidified wafer after cooling. After confirming homogeneity, the furnace temperature was slowly adjusted to the planned initial growth temperature, so that the solution state corresponded to a saturated or slightly supersaturated phase diagram. The inert atmosphere was kept continuously flowing and the temperature was kept stable for a period of time to establish a stable initial dynamic equilibrium, providing conditions for controlled nucleation and epitaxial growth upon subsequent contact with the substrate.

[0063] S200: An axial temperature gradient is established in a liquid phase epitaxial furnace with independent temperature control in multiple zones, and sequential contact between the substrate and different component solution pools is achieved through a programmable sliding boat system;

[0064] Furthermore, establishing an axial temperature gradient within a multi-zone independently temperature-controlled liquid phase epitaxial furnace includes:

[0065] The furnace body is divided into three or more temperature control zones using a zoned temperature control method.

[0066] Target temperatures are set for different regions to create an axial temperature gradient;

[0067] Temperature feedback control is used to maintain temperature stability in each area;

[0068] Combined with insulation measures, the uniformity of the temperature field distribution is controlled.

[0069] Specifically, the liquid phase epitaxial furnace is divided into three or more temperature control zones according to the design. Each zone contains an independent resistance heating element and a composite insulation layer, formed by stacking multiple layers of thermal insulation material, which works in conjunction with the heating element to control the radial temperature difference. A temperature sensor is installed near the substrate in each zone, and each sensor is connected to its respective closed-loop controller, which adjusts the power of the heating element in that zone. An inert gas inlet and outlet are axially positioned within the furnace body. The atmosphere of the furnace cavity is maintained by a continuous axial flow of inert gas, and gas guide plates guide the airflow along the substrate surface to form a stable covering flow field, ensuring uniform airflow coverage.

[0070] The heaters in each temperature-controlled zone are started sequentially according to the program. The closed-loop controller gradually increases the temperature according to the preset target temperature and reaches a stable temperature in each zone. Through real-time feedback from the temperature sensor, the closed-loop controller adjusts the output of the heating element to keep the temperature in each zone stable until the axial temperature distribution reaches the required gradient and remains in a stable state for a certain period of time to complete thermal equilibrium. The actual temperature distribution in each zone is checked using an infrared thermometer inside the furnace cavity or by extracting cooling samples, and the deviation is fine-tuned until the temperature field achieves the required uniformity in both the axial and radial directions.

[0071] Furthermore, the sequential contact between the substrate and different component solution pools via a programmable sliding boat system includes:

[0072] The substrate is mounted on a movable carrier;

[0073] The vehicle's speed and dwell time are controlled according to a preset program;

[0074] The contact area between the substrate and the support surface is reduced by using line contact.

[0075] Ensure that the substrate surface is in full contact with the solution pool while maintaining uniform airflow coverage.

[0076] Specifically, the boat body of the sliding boat system is placed on a high-temperature resistant alloy guide rail. The boat body is made of high-purity graphite or high-temperature resistant metal. Pairs of support components are installed on both sides of the boat, each with an arc-shaped support surface to form line contact with the substrate. The substrate is fixed to a movable carrier, using an edge clamping mechanism to hold it, ensuring the polished surface is exposed and the carrier is aligned with the boat body. The carrier and support components maintain line contact to reduce the contact area and minimize thermal short circuits. A pushing mechanism is connected to a servo driver, allowing for precise linear movement along the guide rail. The servo driver is controlled by a programmable logic controller (PLC).

[0077] The growth sequence is entered into the programmable logic controller (PLC), recording the relative position of each solution pool, the approach speed of the carrier, and the dwell time in place according to the growth layer sequence. Advance / retreat logic and motion limit values ​​are set in the controller to ensure the carrier reaches the predetermined position before contact and retracts according to the program after contact. During contact, the controller simultaneously monitors the temperature sensor output and airflow parameters. If any abnormal temperature or airflow is detected, the controller immediately executes preset protective actions to stop movement and retreat the carrier to a safe position.

[0078] The carrier, carrying the substrate, is smoothly advanced from its initial position along the guide rail to the approach position in front of the first solution pool. The advancement speed is controlled by a programmable controller according to the program, and a closed-loop controller continuously maintains local temperature stability during the advancement process. When the carrier reaches the contact position, it continues to advance precisely at a low speed to the designed contact position, ensuring full contact between the substrate surface and the solution pool. Simultaneously, the support components support the substrate edge with line contact, keeping the substrate surface exposed and covered by airflow. A preset dwell time is maintained at the contact position to complete the material transport and nucleation process. During the dwell time, the gas flow field remains stable, and gas guide plates maintain uniform airflow coverage on the substrate surface. After the dwell time, the controller withdraws the carrier to the non-contact position at a controlled speed. The withdrawal process is smooth to avoid forming large volumes of residual liquid or impacting the substrate surface. The carrier is then withdrawn and moved to the next solution pool, and the above contact steps are repeated until the current layer growth is complete.

[0079] Displacement sensors and visual monitoring devices are installed at key locations in the sliding boat system to confirm the carrier's position and contact status. Signals from the monitoring devices are linked with the programmable controller to form a process interlock. Real-time data from temperature and airflow sensors are input to the closed-loop controller. The closed-loop controller adjusts the heating elements or triggers alarms and protection procedures based on deviations to ensure the axial temperature gradient remains stable throughout the growth process. In case of an anomaly, the controller first uses programmed actions to remove the carrier from the solution bath and move the substrate back to a pre-cooling or safe position. Then, it processes the issue according to a preset procedure and records the fault data for subsequent analysis.

[0080] After this multi-layered programmed contact is completed, the carrier is moved to the reset position and fixed, and the movement of the sliding boat actuator is turned off to put it into standby mode. The temperature curves, carrier displacement records, dwell time records, and process monitoring data from this operation are exported and saved as a basis for process quality traceability.

[0081] S300: During epitaxial growth, lattice constant deviation, surface morphology and photoelectric performance parameters are monitored in real time. When the monitoring signal deviates from the preset range, the solution component concentration and growth temperature are dynamically and collaboratively adjusted to achieve lattice mismatch compensation.

[0082] Furthermore, the step of achieving lattice mismatch compensation includes:

[0083] The difference between the lattice constant of the epitaxial layer and the substrate is monitored in real time by X-ray diffraction. Surface roughness, growth ripples or dislocation density are detected by optical microscopy or scanning electron microscopy. Photoelectric performance parameters are detected by measuring carrier concentration, mobility and emission wavelength.

[0084] When the lattice constant deviation exceeds the set ratio of the substrate lattice constant, a synergistic adjustment mechanism of solution component concentration and growth temperature is adopted to achieve dynamic compensation of lattice mismatch through high temperature-high concentration coupling and thermodynamic compensation effect.

[0085] When the surface roughness exceeds the preset critical value or the dislocation density is abnormal, a step-by-step adjustment mechanism is adopted to first adjust the temperature to optimize the surface mobility and then fine-tune the concentration to repair the lattice distortion.

[0086] When the carrier mobility decreases beyond a preset threshold, growth is paused and in-situ annealing is performed.

[0087] Specifically, the following online detection devices are integrated and operated in parallel within the liquid phase epitaxial furnace: a high-resolution in-situ solution X-ray diffraction module, a long working distance optical microscopy imaging module, an in-situ photoluminescence spectroscopy measurement module, and a sample contact stage for Hall effect measurements during growth intervals. Signals from each detection device are connected to the process data acquisition and control system. Before growth begins, after initial thermal equilibration of the substrate and solution according to the process flow, baseline data is acquired sequentially using X-ray diffraction, optical microscopy, and in-situ photoluminescence spectroscopy. During short pauses, carrier concentration and mobility are measured on the sample contact stage, and the baseline data is written into the process control system as a preset reference range.

[0088] In-situ X-ray diffraction continuously acquires diffraction peak position information of crystal planes. The difference between the lattice constant of the epitaxial layer and the substrate lattice constant is calculated by peak position drift, and this difference is compared with a baseline reference to generate a lattice deviation signal. Optical microscopy is used to acquire real-time images of the substrate surface, and automated analysis is performed to extract surface roughness indicators and ripple morphology characteristics, outputting a surface morphology signal. In-situ photoluminescence measurement is used to periodically acquire emission spectra, extracting emission peak positions and intensities, and outputting photoelectric performance signals. The process control system compares these three signals in real-time against preset allowable ranges; any deviation from the allowable range triggers a response procedure.

[0089] When the lattice deviation calculated by in-situ X-ray diffraction exceeds the allowable range set by the process, the process control system automatically enters the "synchronous adjustment" mode. The control system first instructs the sliding boat to pause its movement and enter a stable position, while maintaining the contact state between the solution and the substrate without mechanical disturbance. The control system then increases the target temperature of the designated heating zone at a controlled rate, allowing the growth zone temperature to rise smoothly to a new steady-state temperature according to a predetermined heating curve. The heating process is executed by a closed-loop temperature controller, which records the temperature curve. During the temperature increase, the control system activates a closed-loop micro-feeding device to inject a pre-prepared high-concentration solute solution into the solution. The injection is metered by a mass flow meter and precisely controlled by a micro-pump. The injection process is carried out under inert gas protection and completed through a sealed transmission channel. After injection, the solution is rapidly mixed by low-speed mechanical stirring within the furnace or micro-vibration of the graphite boat. The control system monitors the recovery trend of the lattice deviation under real-time feedback from in-situ XRD. When the XRD real-time signal returns to the preset range and remains stable within the confirmation period, the control system first stops the injection according to the predetermined procedure, then restores the temperature to the original growth setting at a controlled rate and records all process parameters; if the deviation is not restored, the control system will pause growth and save all monitoring data, prompting manual intervention.

[0090] When image analysis detects that surface roughness or ripple morphology deviates from the allowable range, the process control system automatically switches to "step-by-step adjustment" mode. The control system moderately increases the temperature of the growth zone along a gentle curve to promote surface atomic migration activity. After the temperature increase is completed, it is maintained for a preset period of time to monitor changes in surface morphology. The optical microscopy module continuously acquires and analyzes images. When the surface roughness returns to the allowable range, the system restores the initial settings and continues growth. If the morphology still does not improve after temperature adjustment, the control system performs micro-addition of solute or solvent to correct the supersaturated state of the solution. A short-pulse addition mode is used, combined with mixing. After addition, the system maintains a stable state to monitor the morphology recovery effect. When the morphology parameters recover and remain stable within the confirmation time, the control system terminates the addition and returns the temperature to the growth setting; if it still does not recover, a protection program is activated and growth is stopped pending manual intervention.

[0091] When the peak position of in-situ photoluminescence measurement shifts significantly or the in-situ photoluminescence intensity decreases, or when historical data trends show that the carrier mobility is approaching the warning threshold, the control system executes an intermittent measurement program. The control system smoothly removes the carrier to the sample contact stage according to the program, lowers the temperature to the allowable measurement temperature, activates the sample contact stage to bring the probe to the sample edge, and performs Hall measurements under the action of the integrated magnetic field source to obtain carrier concentration and mobility data. After the measurement, the probe is withdrawn and the substrate is reset to the growth position. If the Hall measurement shows that the mobility decrease exceeds the allowable threshold, the control system initiates an in-situ annealing program, briefly raising the temperature of the growth region to the annealing set temperature under an inert atmosphere and maintaining the annealing time to repair lattice defects. After annealing, the growth temperature is restored at a controlled rate, and Hall measurements are performed again to confirm the mobility recovery. If the mobility recovers to the allowable range after annealing, growth continues and all data is recorded; if the mobility is still abnormal, the control system pauses growth, records all monitoring and processing data, issues a fault alarm, and arranges for manual inspection.

[0092] During each adjustment process, the process control system records the trigger signal, executed actions, temperature profile, injection volume, in-situ XRD curve, image sequence, and in-situ PL spectrum, and writes these records to the process database for traceability. Maximum allowable correction counts and maximum correction times are set for all automatic adjustments. If these limits are exceeded, the interlock system immediately pauses growth and locks the furnace, entering a safe handling mode. If any abnormal atmosphere, heating, or injection system occurs during adjustment, the interlock system prioritizes safe evacuation and saves fault information. This step establishes a triple feedback loop of lattice, morphology, and photoelectric properties, ensuring real-time monitoring and dynamic adjustment of the growth process and avoiding irreversible defects caused by post-processing detection.

[0093] S400: During interlayer switching, the substrate is tilted by tilting the substrate structure, and the residual mother liquor is poured into the collection groove by gravity.

[0094] Furthermore, during interlayer switching, the substrate is tilted by using a tilted substrate structure to guide the residual mother liquor into the collection groove using gravity, including:

[0095] After each epitaxial layer is grown, the substrate is tilted to a preset angle;

[0096] Control the tilt angle and residence time to ensure that the residual mother liquor flows and is collected fully;

[0097] After completing liquid collection, return the substrate to a horizontal position;

[0098] Move to the next solution tank location for subsequent growth.

[0099] Specifically, when the epitaxial growth of this layer is completed, the system controller receives a growth completion signal (triggered by thickness monitoring or dwell time), issues a command to the sliding boat to stop moving and maintain its current position, and simultaneously shuts down all mechanical disturbances (such as rotation or vibration) used for the growth of this layer. The controller brings the solution pool to a steady state in a preset sequence and keeps the solution-substrate interface undisturbed by external forces, entering the interlayer cleaning preparation state.

[0100] The push actuator is in a non-contact standby position. The actuator is a servo-driven push rod mechanism, and its push rod end is equipped with a high-temperature and corrosion-resistant contact pad that matches the contact area with the substrate carrier. After the controller confirms that the carrier is in a standby locked state and detects no abnormalities in the carrier position sensor signal, it sends an action permission signal to the push actuator.

[0101] The push actuator advances at a controlled speed according to a program, contacts the designated push point of the substrate carrier, and applies a controllable force, causing the carrier to tilt around its pre-installed hinge axis. The tilt angle is fed back to the controller in real time by a tilt angle sensor, and closed-loop motion control ensures that the preset angle is reached and maintained. During the tilting process, the sliding boat remains stationary, the system continuously maintains the flow of inert gas to keep the atmosphere stable, and the temperature control closed loop maintains the temperature range required for interlayer switching.

[0102] After the substrate is tilted into position, the mother liquor flows along the substrate surface to its lower edge under gravity, and then flows into a pre-designed collection groove on the downstream side of the boat. This collection groove is a sealed groove integrated with the boat, and its opening is geometrically matched with the lower edge of the substrate to reduce splashing and guide the liquid into the groove. A liquid level sensor and a temperature sensor are installed inside the groove to monitor the liquid collection status in real time. The bottom of the groove is connected to an external recovery tank of the furnace cavity through a sealed drainage channel. The drainage channel is equipped with a high-temperature valve and an external wall penetration seal to maintain the airtightness of the furnace cavity.

[0103] When the liquid level sensor detects that the preset collection volume has been reached, the controller drives the drain valve to open and starts the external recovery pump (e.g., a diaphragm pump or peristaltic pump), drawing the mother liquor in the collection groove through a sealed channel to the external recovery tank. The draining process is monitored and the suction volume is recorded by a flow sensor. After draining is complete, the controller closes the drain valve and activates the inert gas purging device in short pulses. The residual liquid droplets are propelled out along the drain channel by inert gas through the purging port of the collection groove, while simultaneously maintaining a stable furnace atmosphere at a low flow rate. The purging process continues until the liquid level in the groove and the visual monitoring device confirm that there is no visible residual liquid.

[0104] A visual monitoring device (a high-temperature resistant, long-working-distance microscope camera) photographs the substrate surface to confirm that residual liquid has been effectively removed. The images are automatically compared to determine that there is no obvious droplet accumulation on the substrate surface. After visual confirmation, the controller issues a reset command. The push actuator resets the substrate carrier to a horizontal position along the hinge axis at a controlled speed. After the tilt angle sensor confirms accurate reset, the actuator returns to the standby position.

[0105] After the substrate is reset and re-clamped by the carrier locking mechanism, the sliding boat system releases the static lock and smoothly moves the carrier to the approach position of the next solution tank according to the growth program. During the movement, the temperature control closed loop continues to maintain the stability of the axial temperature gradient. Before the sliding boat moves, the controller writes the execution record of this interlayer cleaning (tilt angle, dwell time, aspiration volume, visual confirmation results) into the process database for traceability.

[0106] If any step during the collection or drainage process triggers a signal indicating abnormal liquid level, drainage failure, or visual failure, the interlock system immediately stops the sliding boat movement and maintains the substrate in a tilted or reset safe position. The controller records the fault and issues an alarm for manual inspection and intervention. This step efficiently removes residual mother liquor, avoiding new layer defects caused by impurities or droplet residue, thereby improving the interface cleanliness and overall crystal quality of the multilayer epitaxial structure.

[0107] [Example 2]

[0108] A semiconductor manufacturer needs to produce high-quality core chips for developing next-generation high-speed communication bands. The channel layer and the InP substrate form a lattice-matched heterostructure. Traditional liquid phase epitaxy (LPE) methods, due to temperature fluctuations and component fractionation effects during growth, struggle to precisely control the dynamic matching of the lattice constant, leading to high-density mismatch dislocations (>5×10⁻⁶) at the interface. 4 cm -2 This results in a significant decrease in carrier mobility and an increase in device noise figure, severely impacting high-frequency performance. The overall product yield consistently remains below 60%, failing to meet commercial mass production requirements. Therefore, this invention employs a liquid phase epitaxial growth method and equipment for dynamic control of lattice mismatch, comprising:

[0109] Pre-processing module: includes high-temperature annealing equipment, vapor phase polishing equipment, and wet etching equipment;

[0110] Temperature control module: including multi-zone independent temperature-controlled liquid phase epitaxial furnace;

[0111] Transmission module: includes a programmable sliding boat system;

[0112] Monitoring module: includes X-ray diffraction equipment, optical microscope equipment, and in-situ photoluminescence spectroscopy measurement equipment;

[0113] Control module: includes solution component adjustment equipment and temperature control equipment;

[0114] Cleaning module: includes a tilted substrate structure and a collection groove device.

[0115] Specifically, the pretreatment module uses a high-temperature annealing device to anneal the n-type InP(100) substrate in a H2 atmosphere at 1050℃, followed by vapor phase polishing at 900℃ using HCl to obtain an atomically clean surface. A wet etching device uses an H3PO4:H2O2:H2O (3:1:50) solution to form a V-shaped pit array, providing optimized nucleation sites for subsequent epitaxial growth. The temperature control module's multi-zone independently temperature-controlled liquid phase epitaxial furnace prepares an indium-rich In-Ga-As solution pool according to phase diagram calculations. The programmable sliding boat system of the transport module ensures precise contact between the InP substrate and the solution pool for epitaxial growth.

[0116] During this process, the real-time monitoring and dynamic correction functions unique to this invention were activated. Real-time data from the X-ray diffraction device in the monitoring module showed a slight deviation of +0.08% between the epitaxial layer lattice parameters and the InP substrate in the early stages of growth. The control module then initiated the "cooperative adjustment" mechanism (see S300 process in Example 1). While maintaining growth continuity, the temperature control device made a slight adjustment to the growth region (lowering it by 5°C), and the solution composition control device added a quantitative amount of Ga source material to the solution pool via a precision feeding system. This adjustment operation brought the lattice deviation value detected by the X-ray diffraction device to the optimal matching range of ±0.02% within 30 seconds, and maintained this stable state throughout the subsequent growth stages.

[0117] After the InGaAs channel layer growth is completed, the tilted substrate structure and collection groove device of the cleaning module, as described in Example 1 S400, thoroughly remove the residual mother liquor, providing a clean interface for the subsequent growth of a high-quality barrier layer.

[0118] The results of full-range testing on 10 epitaxial wafers grown in the same batch are shown in the table below:

[0119] Table 1 Comparison data for Solution 1

[0120]

[0121] This embodiment verifies the significant effect of the liquid-phase epitaxial device with dynamic lattice mismatch control of the present invention. Through the coordinated operation of various functional modules and the dynamic correction mechanism, the key technical problem of lattice mismatch control in the InGaAs / InP system is solved from the source. The pretreatment module ensures the substrate surface quality, the temperature control module and the transport module achieve precise growth control, the monitoring module and the control module construct a real-time feedback and dynamic correction system, and the cleaning module maintains the cleanliness of the interlayer interface. Epitaxial materials with extremely low dislocation density, excellent electrical properties, and uniform distribution were successfully prepared, significantly increasing the yield of HEMT structure production from the previous substandard level to over 90%, fully meeting the requirements of large-scale production of high-end RF devices. This fully demonstrates the significant technological innovation value and economic application prospects of the device of the present invention in the field of high-performance compound semiconductor device manufacturing.

[0122] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0123] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present invention. The implementation schemes in the above embodiments can also be further combined or replaced. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A liquid-phase epitaxial growth method with dynamic control of lattice mismatch, characterized in that, include: S100: The substrate is pretreated by high-temperature annealing and vapor phase polishing, and micro-pit structures are formed on the substrate surface by wet etching. Under an inert atmosphere, the ratio of solvent to solute is determined based on the phase diagram data of the target epitaxial layer material, and a homogeneous solution is formed by high-temperature pre-melting. S200: An axial temperature gradient is established in a liquid phase epitaxial furnace with independent temperature control in multiple zones, and sequential contact between the substrate and different component solution pools is achieved through a programmable sliding boat system; S300: During epitaxial growth, lattice constant deviation, surface morphology and photoelectric performance parameters are monitored in real time. When the monitoring signal deviates from the preset range, the solution component concentration and growth temperature are dynamically and collaboratively adjusted to achieve lattice mismatch compensation. S400: During interlayer switching, the substrate is tilted by tilting the substrate structure, and the residual mother liquor is poured into the collection groove by gravity. In step S300, the lattice mismatch compensation step includes: The difference between the lattice constant of the epitaxial layer and the substrate is monitored in real time by X-ray diffraction. Surface roughness, growth ripples or dislocation density are detected by optical microscopy or scanning electron microscopy. Photoelectric performance parameters are detected by measuring carrier concentration, mobility and emission wavelength. When the lattice constant deviation exceeds the set ratio of the substrate lattice constant, a synergistic adjustment mechanism of solution component concentration and growth temperature is adopted to achieve dynamic compensation of lattice mismatch through high temperature-high concentration coupling and thermodynamic compensation effect. When the surface roughness exceeds the preset critical value or the dislocation density is abnormal, a step-by-step adjustment mechanism is adopted to first adjust the temperature to optimize the surface mobility and then fine-tune the concentration to repair the lattice distortion. When the carrier mobility decreases beyond a preset threshold, growth is paused and in-situ annealing is performed. Specifically, the dynamic compensation for lattice mismatch achieved through high-temperature-high-concentration coupling and thermodynamic compensation effects includes: The control system increases the target temperature of the designated heating zone at a controlled rate, so that the temperature of the growth zone rises smoothly to a new steady-state temperature according to the predetermined heating curve. The heating process is executed by the closed-loop temperature controller and the temperature curve is recorded. During the temperature increase process, the control system activates the closed micro-feeding device to inject a pre-prepared high-concentration solute solution into the solution. The injection is metered by a mass flow meter and the injection volume is precisely controlled by a micro pump. The injection process is protected by inert gas and completed through a sealed transmission channel. After injection, the solution is rapidly mixed by low-speed mechanical stirring in the furnace or micro-vibration of the graphite boat, and the control system monitors the recovery trend of lattice deviation under real-time feedback of in-situ XRD. When the XRD real-time signal returns to the preset range and remains stable within the confirmation period, the control system first stops the injection according to the predetermined program, then restores the temperature to the original growth setting at a controlled rate and records the parameters of the entire process. If the deviation is not corrected, the control system will pause growth and save all monitoring data, prompting manual intervention.

2. The liquid-phase epitaxial growth method with dynamic control of lattice mismatch as described in claim 1, characterized in that, In S100, substrate pretreatment and micro-pit structure formation include: high-temperature annealing of the substrate in H2 environment to remove the surface oxide layer, atomically clean surface achieved by HCl vapor phase polishing, and then forming hexagonal V-shaped micro-pits on the substrate surface using a maskless wet etching process.

3. The liquid-phase epitaxial growth method with dynamic control of lattice mismatch as described in claim 1, characterized in that, In S100, the process of forming a homogeneous solution includes: determining the initial ratio of solvent to solute through phase diagram calculations to make the solution saturated or supersaturated at the initial temperature; accurately weighing high-purity metal raw materials and dopants and mixing them according to the calculation results; pre-melting the raw materials at high temperature under inert gas protection to completely dissolve the raw materials and form a homogeneous solution; and adjusting the temperature or composition to make the solution reach a dynamic equilibrium state after contacting the substrate.

4. The liquid-phase epitaxial growth method with dynamic control of lattice mismatch as described in claim 1, characterized in that, In S200, the establishment of the axial temperature gradient includes: The furnace body is divided into three or more temperature control zones using a zoned temperature control method. Target temperatures are set for different regions to create an axial temperature gradient; Temperature feedback control is used to maintain temperature stability in each area; Combined with insulation measures, the uniformity of the temperature field distribution is controlled.

5. The liquid-phase epitaxial growth method with dynamic control of lattice mismatch as described in claim 1, characterized in that, In S200, the sequential contact between the substrate and the different component solution pools includes: The substrate is mounted on a movable carrier; The vehicle's speed and dwell time are controlled according to a preset program; The contact area between the substrate and the support surface is reduced by using line contact. Ensure that the substrate surface is in full contact with the solution pool while maintaining uniform airflow coverage.

6. The liquid-phase epitaxial growth method with dynamic control of lattice mismatch as described in claim 1, characterized in that, In step S400, the treatment of residual mother liquor between layers includes: After each epitaxial layer is grown, the substrate is tilted to a preset angle; Control the tilt angle and residence time to ensure that the residual mother liquor flows and is collected fully; After completing liquid collection, return the substrate to a horizontal position; Move to the next solution tank location for subsequent growth.

7. A liquid phase epitaxy apparatus for dynamic control of lattice mismatch, used to implement the method described in any one of claims 1-6, characterized in that, include: Preprocessing module: Used to execute the S100 process, including high-temperature annealing equipment, vapor phase polishing equipment, and wet etching equipment; Temperature control module: Used to execute the S200 process, including multi-zone independently temperature-controlled liquid phase epitaxial furnace; Transmission module: Used to execute the S200 process, including a programmable sliding boat system; Monitoring module: Used to execute the S300 process, including X-ray diffraction equipment, optical microscope equipment, and in-situ photoluminescence spectroscopy measurement equipment; Control module: Used to execute the S300 process, including solution component adjustment equipment and temperature control equipment; Cleaning module: Used to perform the S400 process, including tilted substrate structure and collection groove device.

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