An iridium crucible electrochemical cathodic protection system and method for gallium oxide melt growth

Abstract

The application relates to the field of crystal growth, and discloses an iridium crucible electrochemical cathode protection system and method for gallium oxide melt growth. The system comprises at least one electric conductor arranged in a gallium oxide melt of an iridium crucible to be protected, each electric conductor is at least partially immersed in the gallium oxide melt, an electrically conductive connecting wire, a direct current power supply, a positive electrode of the direct current power supply is electrically connected to the electric conductor through the electrically conductive connecting wire, and a negative electrode of the direct current power supply is electrically connected to an area of the iridium crucible to be protected which is not covered by the melt. The electric conductor as an anode undergoes an oxidation reaction, and the surface of the iridium crucible to be protected as a cathode is in an electron-rich and negative polarization state. Without significantly changing the growth atmosphere and thermal field conditions, the risk of oxidation of the iridium crucible to be protected can be reduced, thereby effectively reducing the oxidation and volatilization of the inner wall of the iridium crucible to be protected, reducing the pollution of the gallium oxide melt, prolonging the service life of the iridium crucible to be protected, and reducing the overall material and maintenance costs.

Description

Technical Field

[0001] This application relates to the field of crystal growth, and in particular to an iridium crucible electrochemical cathodic protection system and method for gallium oxide melt growth. Background Technology

[0002] When using gallium oxide (Ga2O3) melt for single crystal growth, the iridium crucible supporting the Ga2O3 melt must be exposed to temperatures exceeding 1700°C for extended periods, while simultaneously being directly exposed to a high-temperature oxygen-containing atmosphere. Iridium is easily oxidized and volatilized at high temperatures, and the resulting iridium oxide may fall into the Ga2O3 melt, affecting crystal purity. The crucible wall thickness gradually decreases with the growth cycle, and oxidation of the outer wall can cause deformation or even instability, shortening its lifespan. Furthermore, since iridium is a precious metal, this also increases costs.

[0003] To improve the above-mentioned problems of iridium crucibles, the following methods are currently used: (1) Adjusting the atmosphere: slowing down the oxidation rate by reducing the oxygen partial pressure in the furnace, using inert gas for dilution, and setting a specific oxygen partial pressure window. (2) Adjusting the thermal field: adjusting the crucible temperature field to make the temperature field more uniform, or reducing the local temperature of the outer wall of the crucible. (3) Setting an isolation layer: coating the crucible surface with an oxide coating or using a ceramic / metal composite structure to reduce the direct contact between iridium and oxygen. Currently, these methods are all indirect improvements and have certain defects. For method (1), it cannot fundamentally solve the oxidation reaction tendency of iridium; at the same time, the growth window of gallium oxide has strict requirements on the oxygen partial pressure. Too low an oxygen partial pressure will lead to melt decomposition or oxidation state imbalance, so this method is greatly limited. For method (2), high-temperature melt growth usually requires a specific temperature gradient and a stable hot spot structure. The thermal field cannot be changed significantly to delay oxidation, so this method can only improve locally, but the overall suppression ability is limited. For method (3), in environments exceeding 1700°C, the coating often peels off, cracks, or reacts with gallium oxide melt, introducing secondary pollution; the composite structure generally suffers from mechanical failure due to mismatch in thermal expansion coefficients. Therefore, this method has relatively poor durability and stability.

[0004] Therefore, there is an urgent need for a protection system and method that can actively control the electrochemical reaction tendency of iridium crucibles without significantly altering the overall atmosphere or overall thermal field as the main means, and is suitable for long-term operation. Summary of the Invention

[0005] The purpose of this application is to provide an electrochemical cathodic protection system and method for iridium crucibles used in gallium oxide melt growth, which reduces the risk of oxidation of the iridium crucible to be protected, while reducing melt contamination, extending the service life of the iridium crucible to be protected, and reducing costs.

[0006] To address the aforementioned technical problems, this application provides an iridium crucible electrochemical cathodic protection system for gallium oxide melt growth, comprising: At least one conductor is placed in the gallium oxide melt of the iridium crucible to be protected; each conductor is at least partially immersed in the gallium oxide melt; Conductive connecting wire; A DC power supply, wherein the positive terminal of the DC power supply is electrically connected to the conductor via the conductive connection line, and the negative terminal of the DC power supply is electrically connected to the area of ​​the iridium crucible to be protected not covered by the gallium oxide melt via the conductive connection line; wherein, there is a gap between each conductor and the inner wall of the iridium crucible to be protected.

[0007] Optionally, it further includes: an insulating component for isolating the conductive connection wire from other components, the other components including at least one of a heating furnace body and a heater support.

[0008] Optionally, the insulating component includes an insulating sleeve and an insulating support; The insulating sleeve is fitted onto the outer surface of the conductive connecting wire, and the insulating support is used to fix the conductive connecting wire to the heating furnace body and to isolate the conductive connecting wire from the heating furnace body.

[0009] Optionally, the conductor may comprise an inert metal or a conductive ceramic.

[0010] Optionally, when there are multiple conductors, the multiple conductors are distributed along the axial and / or circumferential direction of the iridium crucible to be protected.

[0011] Optionally, the DC power supply includes a DC power supply module, a control module, and a feedback module. The control module is used to control the output electrical parameters of the DC power supply module. The first end of the feedback module is connected to the control module, and the second end of the feedback module is connected to the detection interface on the conductive connection line. The feedback module is used to collect the actual electrical parameters on the protection circuit and transmit them to the control module; The control module is used to adjust the electrical parameters output by the DC power supply module according to the actual electrical parameters, so that the actual electrical parameters are the target electrical parameters.

[0012] Optionally, it further includes: a gas guiding structure disposed on the outside of the iridium crucible to be protected, and having a gap between it and the outer wall of the iridium crucible to be protected; the gas guiding structure has a gas flow path, and by adjusting at least one of the cross-sectional size, opening ratio, and gas flow direction of the gas flow path, the gas flow rate and oxygen supply in the area where the outer wall of the iridium crucible to be protected is located can be adjusted.

[0013] Optionally, it further includes: a detection device for detecting the morphology of the inner and outer walls of the iridium crucible to be protected after the gallium oxide crystal growth is completed, and / or detecting the mass change and wall thickness change of the iridium crucible to be protected; and / or detecting the composition of the deposits in the heating furnace cavity, and / or detecting the impurity content of the gallium oxide crystal sample.

[0014] Optionally, it further includes: a heat shield structure disposed on the outside of the iridium crucible to be protected, and having a gap between it and the iridium crucible to be protected; the heat shield structure is used to smooth the temperature gradient of the outer wall of the iridium crucible to be protected, reduce the peak temperature of the outer wall of the iridium crucible to be protected, and reduce local hot spots on the outer wall of the iridium crucible to be protected.

[0015] This application also provides an iridium crucible electrochemical cathodic protection method based on the above-described iridium crucible electrochemical cathodic protection system, comprising: When gallium oxide raw material is placed in the iridium crucible to be protected, the positive terminal of the DC power supply is electrically connected to the conductor through a conductive connecting wire, and the conductor is placed in the iridium crucible to be protected. The negative terminal of the DC power supply is electrically connected to the area of ​​the iridium crucible to be protected that is not covered by the gallium oxide melt via the conductive connection line. The gallium oxide raw material is heated to complete melting to form a gallium oxide melt, and the DC power supply outputs current or voltage to form an electrochemical circuit with the DC power supply, the conductor, and the iridium crucible to be protected.

[0016] Optionally, after controlling the output current or voltage of the DC power supply, the method further includes: The feedback module collects the actual electrical parameters on the protection circuit and transmits them to the control module; The control module adjusts the electrical parameters output by the DC power supply module according to the actual electrical parameters, so that the actual electrical parameters are the target electrical parameters.

[0017] Optionally, after the gallium oxide crystal growth is complete, the process further includes: The morphology of the inner and outer walls of the iridium crucible to be protected, and / or the mass of the iridium crucible to be protected, and / or the wall thickness variation of the iridium crucible to be protected are detected using testing equipment and compared with an unprotected iridium crucible.

[0018] The iridium crucible electrochemical cathodic protection system provided in this application includes at least one conductor, a conductive connecting wire, and a DC power supply. The positive terminal of the DC power supply is electrically connected to the conductor via the conductive connecting wire, and the negative terminal of the DC power supply is electrically connected to the area of ​​the iridium crucible to be protected that is not covered by the melt via the conductive connecting wire. Since the material in the iridium crucible to be protected is in a molten state, the gallium oxide melt in the iridium crucible to be protected acts as the electrolyte, and the DC power supply, the conductor, and the iridium crucible to be protected form a circuit. When the DC power supply outputs current or voltage, the iridium crucible to be protected acts as the cathode, and the conductor acts as the anode. The conductor undergoes an oxidation reaction, and the surface of the iridium crucible to be protected is in an electron-rich and negatively polarized state. Without significantly changing the growth atmosphere and thermal field conditions, the oxidation of the iridium crucible to be protected can be reduced, thereby effectively reducing the oxidation and volatilization of the inner wall of the iridium crucible to be protected, reducing gallium oxide melt contamination, extending the service life of the iridium crucible to be protected, and reducing overall material and maintenance costs.

[0019] In addition, this application also provides a protection method with the above advantages. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the structure of an iridium crucible electrochemical cathodic protection system provided in an embodiment of this application; Figure 2 A schematic diagram of an electrochemical circuit formed by an iridium crucible electrochemical cathodic protection system provided in this application embodiment; Figure 3 A flowchart of an iridium crucible electrochemical cathodic protection method provided in this application embodiment; In the figure, 1. Iridium crucible to be protected, 2. Conductor, 3. Conductive connecting wire, 4. DC power supply, 5. Gallium oxide melt. Detailed Implementation

[0022] To enable those skilled in the art to better understand the present application, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are merely some embodiments of the present application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0023] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0024] As described in the background section, the existing technologies for protecting iridium crucibles are all indirect, which has problems such as limited protection capability, easy secondary contamination of gallium oxide melt inside the iridium crucible, and poor protection stability.

[0025] In view of this, this application provides an iridium crucible electrochemical cathodic protection system for gallium oxide melt growth, please refer to... Figure 1 The system may include: At least one conductor 2 is placed in the gallium oxide melt 5 of the iridium crucible 1 to be protected; each conductor 2 is at least partially immersed in the gallium oxide melt 5; Conductive connecting wire 3; A DC power supply 4 is provided. The positive terminal of the DC power supply 4 is electrically connected to the conductor 2 via a conductive connecting line 3, and the negative terminal of the DC power supply 4 is electrically connected to the area of ​​the iridium crucible 1 to be protected that is not covered by the gallium oxide melt 5 via a conductive connecting line 3. There is a gap between each conductor 2 and the inner wall of the iridium crucible 1 to be protected.

[0026] The iridium crucible 1 to be protected is preferably an integral metal structure, with its inner and outer walls maintaining continuous electrical conductivity, thereby forming an equipotential cathode in an electrochemical sense.

[0027] The negative electrode is electrically connected to the area of ​​the iridium crucible 1 not covered by the gallium oxide melt 5 via conductive connection line 3. This is to avoid interference with the interface of the gallium oxide melt 5 and the crystal growth process. The area of ​​the iridium crucible 1 not covered by the gallium oxide melt 5 can be the bottom, outer edge, or outer wall of the iridium crucible 1, which are non-crystalline growth functional areas.

[0028] The gallium oxide melt 5 provides an electrolyte environment at high temperatures, enabling current closure between the cathode and anode through ion migration. The gallium oxide melt 5 defines the current transport path, determines the electric field distribution of the system, and participates in the oxidation reaction in the anode region.

[0029] The gallium oxide melt 5 can be gallium oxide in a fully molten state at high temperatures. Within the crystal growth temperature range, molten gallium oxide has ionic conductivity, and its conductivity is affected by temperature, redox state, impurity content, and uniformity of the gallium oxide melt 5.

[0030] Conductor 2, iridium crucible 1 to be protected, and DC power supply 4 form a complete electrochemical circuit in the environment provided by gallium oxide melt 5. Conductor 2 serves as the anode, iridium crucible 1 to be protected serves as the cathode, and gallium oxide melt 5 serves as the high-temperature ion-conducting medium. The cathodic protection current is limited to ion migration within gallium oxide melt 5, thereby ensuring the effectiveness and controllability of the electrochemical circuit.

[0031] Conductor 2 bears the main oxidation reaction load in the electrochemical circuit, causing the oxidation reaction to preferentially occur in the anodic region, thereby migrating the high-temperature oxidation reaction that might originally occur on the surface of the iridium crucible 1 to conductor 2. The iridium crucible 1 to be protected is the final receiver of electron injection in the system. During system operation, its electrochemical potential is actively regulated to suppress the oxidation reaction at high temperatures. Therefore, in this application, the iridium crucible 1 to be protected not only serves as a container passively holding the gallium oxide melt 5, but also as the protected object, a protected structure in the electrochemical system whose surface state (especially the contact surface with the gallium oxide melt 5) is actively regulated.

[0032] The reaction mode of the conductor 2 includes at least: charge exchange reaction of charged species in gallium oxide melt 5 on the anode side, and / or controllable oxidation consumption reaction of the anode, thereby transferring the oxidation load from the surface of the iridium crucible 1 to be protected to the conductor 2, forming an engineering implementation path of "controllable anode consumption replacing the loss of the iridium crucible 1 to be protected".

[0033] There is a certain gap between the conductor 2 placed in the gallium oxide melt 5 and the iridium crucible 1 to be protected, that is, the conductor 2 and the inner wall of the iridium crucible 1 to be protected are not in direct contact. This avoids the local electric field being too strong, which may cause local reverse polarization or the generation of non-uniform reaction regions in the iridium crucible 1 to be protected, and reduces the influence of anodic reactions (such as local bubbles or local high reaction heat) on the stability of the crystal growth interface.

[0034] The electric field can be homogenized by configuring the number and shape of the conductors 2, thus avoiding excessive local current density.

[0035] It should be noted that the shape of the conductor 2 is not limited in this application, but depends on the volume of the gallium oxide melt 5 and the electric field distribution requirements. For example, the shape of the conductor 2 can be rod-shaped, sheet-shaped, or ring-shaped. The number of conductors 2 is also not limited in this application, but depends on the volume of the gallium oxide melt 5 and the electric field distribution requirements. For example, the number of conductors 2 can be one or at least two, with at least two conductors 2 forming an array structure.

[0036] This application does not limit the type of conductor 2, and any type can be selected. As one possible implementation, the conductor 2 includes an inert metal or a conductive ceramic.

[0037] The materials for conductor 2 can be functionally categorized into two types: inert and consumable. a. Inert anode: Utilizing materials with high chemical stability and conductivity in the high-temperature gallium oxide melt 5 to reduce the risk of anode dissolution or breakage. b. Consumable anode: Employing conductive materials that allow for controlled oxidation or controlled consumption, and designed as replaceable units to handle the primary oxidation load during system operation. The specific material type can be selected based on the temperature of the gallium oxide melt 5, the oxygen partial pressure window, the operating cycle, and the permissible level of impurity introduction.

[0038] In a preferred embodiment, the conductor 2 is an inert material with low dissolution tendency and high chemical stability in the gallium oxide melt 5 environment. Under the process window of low current density for cathodic protection, the intensity of the anodic reaction is limited, and the impurity flux it may introduce can be controlled at a low level. By suppressing the oxidation, volatilization, and structural loss of the iridium crucible 1 to be protected in a high-temperature oxygen-containing environment, under the above process conditions, the new impurity flux that the anode may bring is lower than the pollution flux introduced by the oxidation of the iridium crucible 1 to be protected when no cathodic protection is taken, thereby achieving a reduction in the overall pollution level at the system level.

[0039] The conductor 2 can be fixed to the furnace cover or support by a mechanical structure to ensure the stability of the depth and position after the gallium oxide melt 5 is inserted.

[0040] As one possible implementation, the conductor 2 can be a consumable or replaceable unit used to bear oxidation loss during long-term operation, thereby replacing the body loss of the iridium crucible 1 to be protected with anode consumption.

[0041] Conductor 2 not only serves as the circuit electrode, but also as the active bearing unit for high-temperature oxidation load. Through material selection, geometry and spatial arrangement, oxidation-related reactions are preferentially concentrated in the anode region, thereby significantly suppressing the high-temperature oxidation and volatilization loss of the iridium crucible 1 to be protected.

[0042] The electrochemical circuit formed by DC power supply 4, conductor 2, iridium crucible 1 to be protected, and gallium oxide melt 5 is as follows: Figure 2 As shown, it includes two parts: the external circuit electron flow and the internal ion migration / diffusion of the gallium oxide melt 5.

[0043] I. Electron flow path (external circuit).

[0044] The electron flow in the external circuit follows basic electrochemical principles and closes along the following paths: 1. Anode (conductor 2) → (electrons flow out) → DC power supply 4 positive terminal (+).

[0045] An oxidation reaction occurs at the anode, releasing electrons.

[0046] Electrons enter the external circuit from the anode and flow to the positive terminal of the DC power supply.

[0047] 2. DC power supply 4 positive terminal (+) → (through the inside of DC power supply 4) → DC power supply 4 negative terminal (-).

[0048] Inside DC power supply 4, electrons are re-output from the positive terminal to the negative terminal.

[0049] DC power supply 4 serves as the external circuit closed loop for the electronic pump.

[0050] 3. DC power supply 4 negative terminal (-) → cathode (iridium crucible 1 to be protected).

[0051] The iridium crucible serves as the cathode and receives electron injection from DC power supply 4.

[0052] The surface of the iridium crucible 1 to be protected forms a continuous electron enrichment, making the iridium crucible 1 to be protected more difficult to be oxidized.

[0053] Therefore, the complete path of the external electronic circuit is: anode → positive terminal of DC power supply 4 → inside DC power supply 4 → negative terminal of DC power supply 4 → cathode.

[0054] II. Ion migration path (internal circuit).

[0055] In the gallium oxide melt 5, the molten gallium oxide melt 5 provides high-temperature ionic conductivity, which enables the internal circuit to be closed: ions near the cathode interface migrate towards the anode; the corresponding oxidation reaction occurs at the anode interface, completing the charge conservation process of ions; the internal ion migration / diffusion and the external electron flow together constitute the circuit structure of the electrochemical system.

[0056] The iridium crucible 1 (cathode) continuously gains electrons → the surface of the iridium crucible 1 is in a reduced state → the oxidation tendency is significantly reduced; the anode bears the oxidation load → the oxidation reaction is transferred from the surface of the iridium crucible 1 to the anode; ions migrate through the closed internal circuit inside the gallium oxide melt 5; the positive and negative terminals of the DC power supply 4 → ensure the integrity of the external circuit without any breaks.

[0057] It should be noted that the number of conductors 2 is not limited in this application and can be set arbitrarily. For example, the number of conductors 2 can be one or more (at least two).

[0058] In one embodiment of this application, when there are multiple conductors 2, the multiple conductors 2 are distributed along the axial and / or circumferential direction of the iridium crucible 1 to be protected, so as to achieve electric field homogenization and reduce local current density, thereby making the protection effect of the iridium crucible 1 to be protected more uniform and reducing the impact on gallium oxide crystal growth.

[0059] When there are multiple conductors 2, the DC power supply 4 can selectively apply output to any one of the conductors 2, and / or switch to another backup conductor 2 when a certain conductor 2 malfunctions.

[0060] The crucible protection system provided in this embodiment includes a conductor 2, a conductive connecting line 3, and a DC power supply 4. The positive terminal of the DC power supply 4 is electrically connected to the conductor 2 via the conductive connecting line 3, and the negative terminal of the DC power supply 4 is electrically connected to the area of ​​the iridium crucible 1 to be protected that is not covered by the gallium oxide melt 5 via the conductive connecting line 3. Since the material in the iridium crucible 1 to be protected is in the state of gallium oxide melt 5, the material in the iridium crucible 1 to be protected acts as an electrolyte, and the DC power supply 4, the conductor 2, and the iridium crucible 1 to be protected form a circuit. When the DC power supply 4 outputs current or voltage, the iridium crucible 1 to be protected acts as the cathode, the conductor 2 acts as the anode, and the conductor 2 undergoes an oxidation reaction. The surface of the iridium crucible 1 to be protected is in an electron-rich and negatively polarized state. Without significantly changing the growth atmosphere and thermal field conditions, the risk of oxidation of the iridium crucible 1 to be protected can be reduced, thereby effectively reducing the oxidation and volatilization of the inner wall of the iridium crucible 1 to be protected, reducing gallium oxide melt 5 contamination, extending the service life of the iridium crucible 1 to be protected, and reducing overall material and maintenance costs.

[0061] Based on the above embodiments, in one embodiment of this application, the iridium crucible electrochemical cathodic protection system may further include: an insulating component for isolating the conductive connecting wire 3 from other components, wherein the other components include at least one of a heating furnace body and a heater support.

[0062] In this embodiment, the insulating components can block all electrical contacts on the non-gallium oxide melt 5 path, limiting the current to be closed through the path of "DC power supply 4 → conductor 2 → gallium oxide melt 5 → iridium crucible 1 to be protected → DC power supply 4", preventing the current from forming a bypass through the heating furnace body or other structural components, thereby ensuring the stable realization of the protection effect of the iridium crucible 1 to be protected.

[0063] Insulating components can block bypass currents generated through the heating furnace body, heaters, and / or supports.

[0064] It should be noted that this application does not specifically limit the insulating components; the definition depends on the specific circumstances.

[0065] In one possible implementation, the insulating component includes an insulating sleeve and an insulating support; the insulating sleeve is fitted onto the outer surface of the conductive connecting wire 3, and the insulating support is used to fix the conductive connecting wire 3 to the heating furnace body and to isolate the conductive connecting wire from the heating furnace body.

[0066] In this embodiment, by providing an insulating sleeve on the outer surface of the conductive connecting wire 3, electrical contact between the conductive connecting wire 3 and conductive components that may come into contact with the heating furnace body can be avoided. The insulating support can fix the position of the conductive connecting wire 3 to prevent movement, and at the same time lead the conductive connecting wire 3 out of the heating furnace body.

[0067] Based on any of the above embodiments, in one embodiment of this application, the DC power supply 4 includes a DC power supply module, a control module, and a feedback module. The control module is used to control the output electrical parameters of the DC power supply module. The first end of the feedback module is connected to the control module, and the second end of the feedback module is connected to the detection interface on the conductive connection line 3. The feedback module is used to collect the actual electrical parameters on the protection circuit and transmit them to the control module. The control module is used to adjust the output electrical parameters of the DC power supply module according to the actual electrical parameters so that the actual electrical parameters are the target electrical parameters.

[0068] The target electrical parameters refer to the electrical parameters that need to be achieved in the protection circuit.

[0069] The DC power supply module applies controlled electron injection to the cathode (iridium crucible 1 to be protected), keeping its surface in a reduced state; thus, the oxidation reaction is mainly concentrated at the anode (conductor 2). The control module can also dynamically adjust the cathodic protection intensity according to the system operation stage; judge the anode state and interface changes based on the detection signal, and adjust the strategy accordingly.

[0070] The control module is used not only to output the set target electrical parameters, but also to prevent excessive cathodic protection current from causing disturbances in the gallium oxide melt or causing non-target reactions.

[0071] The control module can collect the voltage U and current I on the protection circuit, calculate the equivalent resistance R=U / I of the gallium oxide melt 5 and track its changes; when R or U undergoes abnormal sudden changes (such as indicating abnormal anode contact, changes in the state of the gallium oxide melt 5 or bypass leakage), the system can automatically perform at least one protection action: reduce the output current, enter the voltage limiting mode, suspend the output and perform circuit self-test, switch the backup conductor 2, adjust the position of the conductor 2, and issue an alarm to ensure stable and reliable cathodic protection.

[0072] The control module can also switch conductor 2 to a backup conductor 2 when an anomaly is detected.

[0073] The detection interface can be either a voltage detection interface or a current detection interface. Correspondingly, the electrical parameters can be voltage and / or current.

[0074] The DC power supply module and control module can adopt constant current, constant potential (voltage) or current-potential hybrid control modes.

[0075] As one possible implementation, the cathodic protection current density or cathodic potential is used as one of the control targets to maintain the surface of the iridium crucible 1 under cathodic protection without inducing disturbance or non-target reactions in the gallium oxide melt 5. Under different sizes of the iridium crucible 1 and volumes of the gallium oxide melt 5, the protection strength can be set within a wide range. For example, the cathodic protection current can be set to a current density of 0.1 mA / cm² for the effective protected area of ​​the iridium crucible 1. 2 Up to 1000 mA / cm 2 The adjustable range is [not specified]. Of course, in practice, it can be adaptively adjusted based on the conductivity, temperature, and process stage of the gallium oxide melt.

[0076] The control module can gradually establish cathode protection by using a current or potential ramp-up strategy during the initial formation stage of gallium oxide melt 5. The ramp-up slope can be set to increase linearly or piecewise over time. During the sensitive stage of crystal growth, the protection intensity can be reduced or finely adjusted, and the shutdown can be gradually reduced to take into account interface stability. During the heat preservation stage and steady-state stage, the protection output can be maintained at a constant level or according to a preset curve.

[0077] In this embodiment, the actual electrical parameters on the protection circuit (i.e., the electrochemical circuit) are collected in real time by the feedback module and fed back to the control module so that the control module can adjust the output of the DC power supply module in real time, thereby enabling the protection system to implement feedback regulation.

[0078] During the growth of gallium oxide melt 5, although the iridium crucible 1 to be protected is in a cathode bias state, its outer wall is still exposed to a high-temperature oxygen-containing atmosphere for a long time. In addition to being affected by the material potential, the oxidation rate of the outer wall is also significantly affected by the gas flow state, oxygen molecule supply rate and local temperature distribution.

[0079] Based on any of the above embodiments, in one embodiment of this application, the crucible protection system may further include: a gas guiding structure disposed on the outside of the iridium crucible 1 to be protected, and having a gap between it and the outer wall of the iridium crucible 1 to be protected; the gas guiding structure has a gas flow path, and by adjusting at least one of the cross-sectional size, opening ratio, and gas flow direction of the gas flow path, the gas flow rate and oxygen supply in the area where the outer wall of the iridium crucible 1 to be protected is located are adjusted.

[0080] The gas guiding structure is electrically isolated from the electrochemical circuit and does not come into contact with the gallium oxide melt 5.

[0081] The gas guiding structure has a gas flow path. By limiting the cross-sectional size, opening ratio or flow direction of the gas flow path, the gas convection velocity in the region adjacent to the outer wall of the iridium crucible 1 to be protected is reduced and the gas renewal rate is slowed down. This prolongs the residence time of the gas near the outer wall of the iridium crucible 1 to be protected, reduces the continuous supply intensity of fresh oxygen, and slows down the gas phase oxidation kinetics of the outer wall of the iridium crucible 1 to be protected.

[0082] It should be noted that this application does not limit the specific type of gas guiding structure, and it can be designed as desired. For example, the gas guiding structure can be a guide hood, a guide ring, a semi-enclosed cavity, or a labyrinth-type airway structure, etc.

[0083] In one embodiment of this application, the iridium crucible electrochemical cathodic protection system may further include: a heat shield structure disposed on the outside of the iridium crucible 1 to be protected, and having a gap between it and the iridium crucible 1 to be protected; the heat shield structure is used to smooth the temperature gradient of the outer wall of the iridium crucible 1 to be protected, reduce the peak temperature of the outer wall of the iridium crucible 1 to be protected, and reduce local hot spots on the outer wall of the iridium crucible 1 to be protected.

[0084] The thermal shield structure is electrically isolated from the electrochemical circuit and does not come into contact with the gallium oxide melt.

[0085] The heat shield structure can be arranged with the reflective surface facing the outer wall of the iridium crucible 1 to be protected, in order to smooth the temperature gradient of the outer wall of the iridium crucible 1 to be protected, reduce the peak temperature of the outer wall and reduce the formation of local hot spots.

[0086] The heat shield structure can be single-layered or multi-layered. By controlling the number of layers, material type, and distance between the heat shield structure and the outer wall of the iridium crucible 1 to be protected, the thermal radiation and convection environment of the outer wall can be improved without changing the overall thermal field design.

[0087] Since the outer wall of the iridium crucible 1 to be protected lacks an electrolyte, it does not form an electrochemical circuit and does not participate in the electrochemical closure of the anode-gallium oxide melt 5-cathode. Therefore, the gas guiding structure and the heat shield structure will not generate a continuous electrochemical reaction like the inner wall cathodic protection, and only play an auxiliary role in improving the environment.

[0088] Based on the above embodiments, in one embodiment of this application, the crucible protection system may further include: a detection device for detecting the morphology of the inner and outer walls of the iridium crucible 1 to be protected after the gallium oxide crystal growth is completed, and / or detecting the mass change and wall thickness change of the iridium crucible 1 to be protected; and / or detecting the composition of the deposits in the heating furnace cavity; and / or detecting the impurity content of the gallium oxide melt 5 and the crystal sample.

[0089] The testing equipment may include a microscope to detect the morphology of the inner and outer walls of the iridium crucible 1 to be protected; the testing equipment may include a weighing meter to measure the mass change of the iridium crucible 1 to be protected before and after the growth of the gallium oxide melt 5 into a crystal; and the testing equipment may include a vernier caliper to measure the wall thickness change of the iridium crucible 1 to be protected before and after the growth of the gallium oxide melt 5 into a crystal.

[0090] In this embodiment, the morphology, quality, and wall thickness changes of the iridium crucible 1 to be protected before and after the growth of the crystal in the gallium oxide melt 5 can be detected by the detection equipment. The results of the changes can be compared with the control furnace without cathodic protection to quantify the comprehensive suppression effect of this application on the high-temperature oxidation, volatilization, structural failure and contamination of the iridium crucible 1 to be protected.

[0091] This application also provides an iridium crucible electrochemical cathodic protection method based on the above-described iridium crucible electrochemical cathodic protection system. Please refer to [reference needed]. Figure 3 The method may include: Step S101: When gallium oxide raw material is placed in the iridium crucible to be protected, the positive terminal of the DC power supply is electrically connected to the conductor through a conductive connecting wire, and the conductor is placed in the iridium crucible to be protected.

[0092] The target material is the material required for crystal growth. The target material will be heated to form a melt, which will then grow into a crystal.

[0093] Step S102: Connect the negative terminal of the DC power supply to the area of ​​the iridium crucible to be protected that is not covered by the gallium oxide melt via a conductive connection wire.

[0094] Step S103: Heat the gallium oxide raw material until it is completely melted to form a gallium oxide melt, and control the DC power supply to output current or voltage so that the DC power supply, the conductor, and the iridium crucible to be protected form an electrochemical circuit.

[0095] This step employs a gradual escalation strategy to progressively establish cathodic protection.

[0096] During step S103, the control module in the DC power supply can acquire the voltage U and / or current I on the circuit, and perform closed-loop regulation of the DC power supply output based on the acquisition results, so that the voltage and / or current on the circuit reach the target electrical parameters.

[0097] The equivalent resistance R of the gallium oxide melt is calculated based on the voltage U and current I in the circuit. When an abnormal change in voltage U, current I or equivalent resistance R is detected, at least one action is performed: reducing the output current, entering the voltage limiting mode, pausing the output and performing a circuit self-test, switching to a backup conductor, or adjusting the position of the conductor.

[0098] The protection strength of the iridium crucible to be protected is adjusted in stages according to the gallium oxide crystal growth stage. The stage adjustment includes: gradual increase in the melt formation stage, decrease or fine adjustment in the crystal growth sensitive stage, maintenance in the steady state stage, and gradual decrease until the power supply is stopped after the crystal growth is completed.

[0099] After crystal growth is complete, the control module gradually reduces the cathodic protection intensity until power is stopped, and the process ends after cooling to a suitable temperature.

[0100] It should be noted that before heating the gallium oxide raw material to a complete melt to form a gallium oxide melt, it is necessary to confirm through detection that a reliable conductive relationship has been established between the cathode, anode and melt (i.e., an electrochemical circuit has been formed), and to ensure that there is no current bypass formed through the furnace body, heater and / or support components.

[0101] The DC power supply gradually applies protection to the iridium crucible to be protected, establishing a stable ion migration path between the anode and cathode in the melt, and causing the surface of the iridium crucible to enter an electron-rich state.

[0102] As one possible implementation method, the cathodic protection current can be gradually increased to allow the iridium crucible to be protected to enter a state of overall cathodicization, thereby avoiding melt disturbance caused by potential abrupt changes.

[0103] At different stages of crystal growth, the protection of the iridium crucible can be dynamically controlled: based on factors such as temperature, interface state, and melt stability, the protection current or potential can be dynamically adjusted by controlling the module to keep the cathodic protection effect within an appropriate range.

[0104] The control process can include: a stable holding phase; slow adjustment in response to temperature changes; feedback adjustment based on changes in protection circuit voltage; fine-tuning of protection strength during sensitive phases; and gradual reduction during shutdown. These strategies enable the system to adapt to various actual operating conditions.

[0105] Regarding the abnormal detection and protection actions in dynamic control, if an abnormal increase in loop voltage is detected during dynamic control (which may correspond to anode passivation, changes in anode insertion depth, or poor contact), or an abnormal decrease in loop voltage is detected accompanied by an abnormal temperature rise in the furnace body / structural components (which may correspond to the formation of a current bypass), the control module can perform at least one action: reduce the output current, enter the voltage limiting mode, suspend the output and perform loop self-test, switch the backup anode channel, or adjust the anode position; after the abnormality is eliminated, the output is restored according to the gradual increase strategy to avoid cathodic protection failure or adverse effects on growth stability.

[0106] The electrochemical cathodic protection method for iridium crucibles provided in this embodiment establishes an electrochemical protection circuit for the iridium crucible to be protected through a melt, a conductor, a conductive connecting wire, and a DC power supply. The iridium crucible to be protected acts as the cathode, and the conductor acts as the anode. The conductor undergoes an oxidation reaction, and the surface of the iridium crucible to be protected is in an electron-rich and negatively polarized state, thereby preventing oxidation of the iridium crucible. Therefore, this embodiment essentially inhibits the oxidation of the iridium crucible to be protected, thereby effectively reducing oxidation and volatilization of the inner wall of the iridium crucible to be protected, reducing melt contamination, extending the service life of the iridium crucible to be protected, and reducing overall material and maintenance costs.

[0107] Based on any of the above embodiments, in one embodiment of this application, after controlling the output current or voltage of the DC power supply, the crucible protection method may further include: The feedback module collects the actual electrical parameters on the protection circuit and transmits them to the control module; The control module adjusts the electrical parameters output by the DC power supply module according to the actual electrical parameters, so that the actual electrical parameters are the target electrical parameters.

[0108] In this embodiment, the output of the DC power supply module can be adjusted in real time by measuring the actual electrical parameters on the protection circuit.

[0109] Based on any of the above embodiments, in one embodiment of this application, the iridium crucible electrochemical cathodic protection method may further include: A gas guiding structure is set on the outside of the iridium crucible to be protected, and the cross-sectional size, opening ratio or flow direction of the gas flow path in the gas guiding structure is adjusted.

[0110] In this embodiment, by setting up a gas guiding structure, the gas conditions outside the iridium crucible to be protected can be adjusted, thereby improving the oxidation conditions and slowing down the oxidation.

[0111] Based on any of the above embodiments, in one embodiment of this application, the iridium crucible electrochemical cathodic protection method may further include: setting a heat shield structure on the outside of the iridium crucible to be protected.

[0112] By setting up a heat shield structure, the temperature environment on the outside of the iridium crucible to be protected can be improved, the temperature gradient on the outer wall of the iridium crucible to be protected can be smoothed, the peak temperature on the outer wall can be reduced, and the formation of local hot spots can be reduced.

[0113] Based on any of the above embodiments, in one embodiment of this application, after the gallium oxide crystal growth is completed, the iridium crucible electrochemical cathodic protection method may further include: The morphology of the inner and outer walls of the iridium crucible to be protected, and / or the mass of the iridium crucible to be protected, and / or the wall thickness variation of the iridium crucible to be protected are detected using testing equipment and compared with an unprotected iridium crucible.

[0114] And / or, using detection equipment to detect the composition of the deposits in the heating furnace cavity, and / or, the impurity content of gallium oxide melt and crystal samples.

[0115] In this embodiment, after the crystal growth is completed, the changes in the morphology, quality, and wall thickness of the iridium crucible to be protected before and after the crystal growth in the melt are detected. The results of these changes can be compared with those of a control furnace without cathodic protection, so as to quantify the comprehensive suppression effect of this application on the high-temperature oxidation, volatilization, structural failure, and contamination of the iridium crucible to be protected.

[0116] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0117] The above provides a detailed description of the iridium crucible electrochemical cathodic protection system and method for gallium oxide melt growth provided in this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are merely for the purpose of helping to understand the solution and core ideas of this application. It should be noted that those skilled in the art can make various improvements and modifications to this application without departing from its principles, and these improvements and modifications also fall within the protection scope of this application.

Claims

1. An iridium crucible electrochemical cathodic protection system for gallium oxide melt growth, characterized in that, include: At least one conductor is provided for placement in the gallium oxide melt of the iridium crucible to be protected; each conductor is at least partially immersed in the gallium oxide melt. Conductive connecting wire; A DC power supply, wherein the positive terminal of the DC power supply is electrically connected to the conductor via the conductive connection line, and the negative terminal of the DC power supply is electrically connected to the area of ​​the iridium crucible to be protected not covered by the gallium oxide melt via the conductive connection line; wherein, there is a gap between each conductor and the inner wall of the iridium crucible to be protected.

2. The iridium crucible electrochemical cathodic protection system as described in claim 1, characterized in that, Also includes: An insulating component is provided to isolate the conductive connection wire from other components, including at least one of a heating furnace body and a heater support.

3. The iridium crucible electrochemical cathodic protection system as described in claim 2, characterized in that, The insulating components include an insulating sleeve and an insulating support; The insulating sleeve is fitted onto the outer surface of the conductive connecting wire, and the insulating support is used to fix the conductive connecting wire to the heating furnace body and to isolate the conductive connecting wire from the heating furnace body.

4. The iridium crucible electrochemical cathodic protection system as described in claim 1, characterized in that, The conductor may be an inert metal or a conductive ceramic.

5. The iridium crucible electrochemical cathodic protection system as described in claim 1, characterized in that, When there are multiple conductors, the multiple conductors are distributed along the axial and / or circumferential direction of the iridium crucible to be protected.

6. The iridium crucible electrochemical cathodic protection system as described in claim 1, characterized in that, The DC power supply includes a DC power supply module, a control module, and a feedback module. The control module is used to control the output electrical parameters of the DC power supply module. The first end of the feedback module is connected to the control module, and the second end of the feedback module is connected to the detection interface on the conductive connection line. The feedback module is used to collect the actual electrical parameters on the protection circuit and transmit them to the control module; The control module is used to adjust the electrical parameters output by the DC power supply module according to the actual electrical parameters, so that the actual electrical parameters are the target electrical parameters.

7. The iridium crucible electrochemical cathodic protection system as described in claim 1, characterized in that, Also includes: A gas guiding structure is disposed on the outside of the iridium crucible to be protected and has a gap between it and the outer wall of the iridium crucible to be protected; the gas guiding structure has a gas flow path, and by adjusting at least one of the cross-sectional size, opening ratio, and gas flow direction of the gas flow path, the gas flow rate and oxygen supply in the area where the outer wall of the iridium crucible to be protected is located can be adjusted.

8. The iridium crucible electrochemical cathodic protection system as described in claim 1, characterized in that, Also includes: The detection equipment is used to detect the morphology of the inner and outer walls of the iridium crucible to be protected after the gallium oxide crystal growth is completed, and / or to detect the mass change and wall thickness change of the iridium crucible to be protected; and / or to detect the composition of the deposits in the heating furnace cavity, and / or to detect the impurity content of the gallium oxide crystal sample.

9. The iridium crucible electrochemical cathodic protection system according to any one of claims 1 to 8, characterized in that, Also includes: A heat shield structure is disposed on the outside of the iridium crucible to be protected, and there is a gap between the heat shield structure and the iridium crucible to be protected; The heat shield structure is used to smooth the temperature gradient of the outer wall of the iridium crucible to be protected, reduce the peak temperature of the outer wall of the iridium crucible to be protected, and reduce local hot spots on the outer wall of the iridium crucible to be protected.

10. An iridium crucible electrochemical cathodic protection method based on the iridium crucible electrochemical cathodic protection system of claim 1, characterized in that, include: When gallium oxide raw material is placed in the iridium crucible to be protected, the positive terminal of the DC power supply is electrically connected to the conductor through a conductive connecting wire, and the conductor is placed in the iridium crucible to be protected. The negative terminal of the DC power supply is electrically connected to the area of ​​the iridium crucible to be protected that is not covered by the gallium oxide melt via the conductive connection line. The gallium oxide raw material is heated to complete melting to form a gallium oxide melt, and the DC power supply outputs current or voltage to form an electrochemical circuit with the DC power supply, the conductor, and the iridium crucible to be protected.

11. The iridium crucible electrochemical cathodic protection method as described in claim 10, characterized in that, After controlling the output current or voltage of the DC power supply, the method further includes: The feedback module collects the actual electrical parameters on the protection circuit and transmits them to the control module; The control module adjusts the electrical parameters output by the DC power supply module according to the actual electrical parameters, so that the actual electrical parameters are the target electrical parameters.

12. The iridium crucible electrochemical cathodic protection method as described in claim 10 or 11, characterized in that, After the gallium oxide crystal growth is complete, the following steps are also included: The morphology of the inner and outer walls of the iridium crucible to be protected, and / or the mass of the iridium crucible to be protected, and / or the wall thickness variation of the iridium crucible to be protected are detected using testing equipment and compared with an unprotected iridium crucible.

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