A method for controlling the flow ratio between inner and outer chambers of MOCVD equipment

Abstract

The present invention provides a method for controlling the flow ratio of inner and outer cavities of MOCVD equipment, which relates to the technical field of MOCVD tail gas control, and comprises an inner cavity and an outer cavity, wherein the tail of the inner cavity is provided with an inner cavity tail gas filter, a first high-precision closed-loop control instrument, a first sensor, a first PID, a first analog quantity pair instrument, an inner cavity electric regulating valve, and an inner cavity flow meter which are connected in sequence, and the tail of the outer cavity is provided with an outer cavity tail gas filter, a second high-precision closed-loop control instrument, a second sensor, a second PID, a second analog quantity pair instrument, an outer cavity electric regulating valve, and an outer cavity flow meter which are connected in sequence, and a PUMP is connected to the ends of the inner cavity flow meter and the outer cavity flow meter, thereby ensuring the accuracy of the reaction, improving the quality of the product, promoting the uniformity and consistency of material growth, and an appropriate flow ratio can avoid unnecessary gas flow, reduce energy consumption, and reduce production costs.

Description

Technical Field

[0001] The invention relates to the technical field of MOCVD tail gas control, and more specifically, to a method for controlling the flow ratio of inner and outer cavities of MOCVD equipment. Background Art

[0002] In the reaction chamber of MOCVD equipment, there is an inner cavity and an outer cavity. The main gases, such as MO source and hydride source, flow in the inner cavity, and there are only some protective gases (such as nitrogen, hydrogen, etc.) in the outer cavity. The inner cavity is generally made of materials such as quartz and graphite. It is impossible to completely seal the inner cavity and the outer cavity, and there will always be gas exchange between the inner and outer cavities.

[0003] If there is exchange between the inner cavity and the outer cavity, the flow ratio of the exchange needs to be controlled. Otherwise, the product quality will be reduced, affecting the uniformity and consistency of material growth. At the same time, energy will be seriously wasted and the service life of the equipment will be shortened. Therefore, the flow ratio between the inner cavity and the outer cavity of the MOCVD equipment must be controlled.

[0004] Therefore, in view of this, the existing structure and defects are studied and improved, and a method for controlling the flow ratio between the inner and outer cavities of MOCVD equipment is provided, in order to achieve a more practical purpose. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a method for controlling the flow ratio between the inner and outer chambers of an MOCVD device to solve the above problems.

[0006] The present invention provides a method for controlling the flow ratio between the inner and outer cavities of an MOCVD device, which is achieved by the following specific technical means:

[0007] A method for controlling the flow ratio between inner and outer cavities of an MOCVD device comprises an inner cavity and an outer cavity, wherein the tail of the inner cavity is provided with an inner cavity exhaust filter, a first high-precision closed-loop control instrument, a first sensor, a first PID, a first analog quantity pair instrument, an inner cavity electric regulating valve, and an inner cavity flow meter which are connected in sequence, and the tail of the outer cavity is provided with an outer cavity exhaust filter, a second high-precision closed-loop control instrument, a second sensor, a second PID, a second analog quantity pair instrument, an outer cavity electric regulating valve, and an outer cavity flow meter which are connected in sequence, and a PUMP is connected between the ends of the inner cavity flow meter and the outer cavity flow meter.

[0008] Further, the specific steps are as follows:

[0009] 8) Check whether all parts are installed properly and working properly;

[0010] 9) Start the MOCVD equipment, the inner and outer chambers start working, and the gas flows in them to react;

[0011] 10) The exhaust gas generated in the inner cavity is first filtered through the inner cavity exhaust gas filter to remove impurities and particulate matter, and the exhaust gas generated in the outer cavity is filtered through the outer cavity exhaust gas filter;

[0012] 11) The filtered exhaust gas in the inner cavity reaches the first high-precision closed-loop control instrument, which measures the relevant parameters of the exhaust gas, and the filtered exhaust gas in the outer cavity reaches the second high-precision closed-loop control instrument for parameter measurement;

[0013] 12) The first sensor detects the temperature of the inner cavity exhaust gas and other physical quantities, and transmits the data to the first PID. The first PID performs calculations based on the set temperature value and the actual temperature value detected by the first sensor, and outputs a control signal. The second sensor detects the temperature of the outer cavity exhaust gas and other information, and transmits it to the second PID;

[0014] 13) The first analog quantity pair instrument processes and converts the control signal output by the first PID. The processed signal acts on the inner cavity electric regulating valve. The regulating valve adjusts the opening according to the signal to control the flow of the inner cavity. The second PID performs calculations and outputs control signals to the second analog quantity pair instrument. After the second analog quantity pair instrument processes and converts the control signal, it acts on the outer cavity electric regulating valve to control the flow of the outer cavity.

[0015] The inner cavity flowmeter measures the actual flow of the inner cavity exhaust gas in real time and feeds the flow data back to the control system. The outer cavity flowmeter measures the actual flow of the outer cavity exhaust gas. The flow data measured by the inner cavity flowmeter and the outer cavity flowmeter are transmitted to the PUMP. The PUMP adjusts the suction power according to the received flow data to control the flow ratio between the actual inner cavity and the outer cavity.

[0016] Furthermore, when the opening degree of the outer cavity electric regulating valve is 8%, the reading of the outer cavity flowmeter is 0.4, the degree of the inner cavity flowmeter is 40, and the flow ratio between the inner cavity and the outer cavity is 100:1; when the opening degree of the outer cavity electric regulating valve is 10%, the reading of the outer cavity flowmeter is 0.5, the degree of the inner cavity flowmeter is 50, and the flow ratio between the inner cavity and the outer cavity is 100:1; when the opening degree of the outer cavity electric regulating valve is 16%, the reading of the outer cavity flowmeter is 0.8, the degree of the inner cavity flowmeter is 80, and the flow ratio between the inner cavity and the outer cavity is 100:1.

[0017] Furthermore, the inner cavity flow meter, the outer cavity flow meter and the PUMP are electrically connected.

[0018] Furthermore, the inner cavity electric regulating valve is a large-diameter regulating valve, and the outer cavity electric regulating valve is a small-diameter regulating valve.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The flow rate of the inner cavity exhaust gas is controlled by using the inner cavity exhaust gas filter, the first high-precision closed-loop control instrument, the first sensor, the first PID, the first analog quantity pair instrument, the inner cavity electric regulating valve, and the inner cavity flow meter connected with the inner cavity; the flow rate of the outer cavity exhaust gas is controlled by using the outer cavity exhaust gas filter, the second high-precision closed-loop control instrument, the second sensor, the second PID, the second analog quantity pair instrument, the outer cavity electric regulating valve, and the outer cavity flow meter connected with the outer cavity, so as to control the flow ratio between the inner cavity and the outer cavity to be in an optimal state, thereby ensuring the accuracy of the reaction, improving the quality of the product, and promoting the uniformity and consistency of material growth. The appropriate flow ratio can avoid unnecessary gas flow, reduce energy consumption, and reduce production costs. The stable flow ratio can reduce the impact and erosion of the airflow on the internal components of the reaction chamber, thereby also extending the service life of the equipment.

[0021] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a flow chart of the present invention.

[0023] In the figure, the corresponding relationship between the component names and the figure numbers is as follows:

[0024] 1. Inner cavity; 2. Inner cavity exhaust filter; 3. First high-precision closed-loop control instrument; 4. First sensor; 5. First PID; 6. First analog quantity pair instrument; 7. Inner cavity electric regulating valve; 8. Inner cavity flow meter; 9. Outer cavity; 10. Outer cavity exhaust filter; 11. Second high-precision closed-loop control instrument; 12. Second sensor; 13. Second PID; 14. Second analog quantity pair instrument; 15. Outer cavity electric regulating valve; 16. Outer cavity flow meter; 17. PUMP. DETAILED DESCRIPTION

[0025] The following embodiments of the present invention are described in further detail in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0026] In the description of the present invention, unless otherwise specified, "plurality" means two or more than two; the orientations or positional relationships indicated by the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0027] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. Example

[0028] As attached Figure 1 As shown:

[0029] The present invention provides a method for controlling the flow ratio of the inner and outer cavities of an MOCVD device, comprising an inner cavity 1 and an outer cavity 9, wherein the tail of the inner cavity 1 is provided with an inner cavity tail gas filter 2, a first high-precision closed-loop control instrument 3, a first sensor 4, a first PID5, a first analog quantity pair instrument 6, an inner cavity electric regulating valve 7, and an inner cavity flow meter 8, which are connected in sequence, and the tail of the outer cavity 9 is provided with an outer cavity tail gas filter 10, a second high-precision closed-loop control instrument 11, a second sensor 12, a second PID13, a second analog quantity pair instrument 14, an outer cavity electric regulating valve 15, and an outer cavity flow meter 16, which are connected in sequence, and the inner cavity flow meter 8 is connected to the end of the outer cavity flow meter 16 by a PUMP 17. The inner cavity tail gas filter 2 can filter impurities and particulate matter in the inner cavity tail gas to prevent them from entering the device and causing damage or affecting the measurement accuracy, and the first high-precision closed-loop control instrument 3 accurately measures and monitors the temperature, pressure, flow and other parameters of the inner cavity tail gas. The first PID5 performs calculations based on the proportional, integral, differential operations and the actual value detected by the first sensor 4, and accurately adjusts the parameters such as the temperature of the inner cavity to keep it near the set value. The first analog quantity instrument 6 processes and converts the analog signal and transmits it to the inner cavity electric regulating valve 7. The inner cavity electric regulating valve 7 adjusts the opening according to the signal to control the flow rate of the inner cavity exhaust gas. The inner cavity flowmeter 8 measures the actual flow rate of the inner cavity exhaust gas in real time and feeds the data back to the control system.

[0030] The specific steps are as follows:

[0031] 14) Check whether all parts are installed properly and working properly;

[0032] 15) Start the MOCVD equipment, the inner chamber 1 and the outer chamber 9 start to work, and the gas flows in them to react;

[0033] 16) The exhaust gas generated in the inner cavity 1 first passes through the inner cavity exhaust gas filter 2 to filter out impurities and particulate matter therein, and the exhaust gas generated in the outer cavity 9 passes through the outer cavity exhaust gas filter 10 to filter;

[0034] 17) The filtered exhaust gas in the inner cavity 1 reaches the first high-precision closed-loop control instrument 3, which measures the relevant parameters of the exhaust gas, and the filtered exhaust gas in the outer cavity 9 reaches the second high-precision closed-loop control instrument 11 for parameter measurement;

[0035] 18) The first sensor 4 detects the temperature of the exhaust gas in the inner cavity 1 and other physical quantities, and transmits the data to the first PID 5. The first PID 5 performs calculations based on the set temperature value and the actual temperature value detected by the first sensor 4, and outputs a control signal. The second sensor 12 detects the temperature of the exhaust gas in the outer cavity 9 and other information, and transmits it to the second PID 13;

[0036] 19) The first analog quantity pair instrument 6 processes and converts the control signal output by the first PID5. The processed signal acts on the inner cavity electric regulating valve 7. The regulating valve adjusts the opening according to the signal to control the flow of the inner cavity 1. The second PID 13 performs calculations and outputs the control signal to the second analog quantity pair instrument 14. After the second analog quantity pair instrument 14 processes and converts the control signal, it acts on the outer cavity electric regulating valve 15 to control the flow of the outer cavity 9.

[0037] The inner cavity flow meter 8 measures the actual flow of the exhaust gas in the inner cavity 1 in real time, and feeds the flow data back to the control system. The outer cavity flow meter 16 measures the actual flow of the exhaust gas in the outer cavity 9. The flow data measured by the inner cavity flow meter 8 and the outer cavity flow meter 16 are transmitted to PUMP17. PUMP17 adjusts the suction power according to the received flow data to control the flow ratio between the actual inner cavity 1 and the outer cavity 9.

[0038] Among them, when the opening of the outer cavity electric regulating valve 15 is 8%, the reading of the outer cavity flowmeter 16 is 0.4, the degree of the inner cavity flowmeter 8 is 40, and the flow ratio between the inner cavity 1 and the outer cavity 9 is 100:1. When the opening of the outer cavity electric regulating valve 15 is 10%, the reading of the outer cavity flowmeter 16 is 0.5, the degree of the inner cavity flowmeter 8 is 50, and the flow ratio between the inner cavity 1 and the outer cavity 9 is 100:1. When the opening of the outer cavity electric regulating valve 15 is 16%, the reading of the outer cavity flowmeter 16 is 0.8, the degree of the inner cavity flowmeter 8 is 80, and the flow ratio between the inner cavity 1 and the outer cavity 9 is 100:1. The experimental data can be used to verify the specific operation of the equipment and the feasibility of the experiment.

[0039] Among them, the inner cavity flow meter 8, the outer cavity flow meter 16 are electrically connected to the PUMP 17. PUMP is a vacuum pump, and the inner cavity flow meter 8, the outer cavity flow meter 16 and the PUMP 17 are connected to transmit the actual flow data of the inner cavity 1 and the outer cavity 9 to the PUMP 17 in real time, so that the PUMP 17 can timely understand the current flow situation, and the inner cavity flow meter 8 and the outer cavity flow meter 16 provide accurate flow information for the PUMP 17, so that it can accurately adjust the suction power and speed according to the flow requirements of the inner cavity 1 and the outer cavity 9, thereby realizing the precise control of the flow ratio between the inner cavity and the outer cavity, and the three operate in coordination.

[0040] The inner cavity electric regulating valve 7 is a large-caliber regulating valve, and the outer cavity electric regulating valve 15 is a small-caliber regulating valve. The inner cavity has a large airflow rate, and a large-caliber regulating valve is required to meet a large flow adjustment range, while the outer cavity is mainly protective gas, and the flow demand is relatively small, thereby achieving a more accurate control of the flow ratio between the outer cavity 9 and the inner cavity 1, reducing equipment costs and energy saving.

[0041] When in use, the MOCVD equipment is started, the inner cavity 1 and the outer cavity 9 start working, the gas flows and reacts therein, the exhaust gas generated in the inner cavity first passes through the inner cavity exhaust filter 2 to filter out impurities and particulate matter therein, and the filtered exhaust gas reaches the first high-precision closed-loop control instrument 3, the instrument measures the relevant parameters of the exhaust gas, the first sensor 4 detects the temperature and other physical quantities of the exhaust gas, and transmits the data to the first PID5, the first PID5 performs calculations based on the set temperature value and the actual temperature value detected by the first sensor 4, and outputs a control signal, the first analog quantity instrument 6 processes and converts the control signal output by the first PID5, the processed signal acts on the inner cavity electric regulating valve 7, the regulating valve adjusts the opening according to the signal, thereby controlling the flow rate of the inner cavity, the inner cavity flowmeter 8 measures the actual flow rate of the inner cavity exhaust gas in real time, and The flow data is fed back to the control system, the exhaust gas generated in the outer cavity is filtered through the outer cavity exhaust gas filter 10, and the filtered exhaust gas reaches the second high-precision closed-loop control instrument 11 for parameter measurement. The second sensor 12 detects the temperature of the outer cavity exhaust gas and other information, and transmits it to the second PID13. The second PID13 performs calculations and outputs control signals to the second analog quantity pair instrument 14. After the second analog quantity pair instrument 14 processes and converts the control signal, it acts on the outer cavity electric regulating valve 15 to control the flow of the outer cavity. The outer cavity flowmeter 16 measures the actual flow of the outer cavity exhaust gas. The flow data measured by the inner cavity flowmeter 8 and the outer cavity flowmeter 16 are transmitted to the PUMP vacuum pump 17. The vacuum pump 17 adjusts the vacuum power according to the received flow data to realize the flow ratio control between the inner cavity and the outer cavity.

[0042] The embodiments of the present invention are given for the purpose of illustration and description, and are not intended to be exhaustive or to limit the invention to the disclosed forms. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments are selected and described in order to better illustrate the principles and practical applications of the present invention and to enable those of ordinary skill in the art to understand the present invention and thereby design various embodiments with various modifications suitable for specific uses.

Claims

1. A method for controlling the flow ratio between inner and outer chambers of an MOCVD device, comprising an inner chamber (1) and an outer chamber (9), characterized in that: The tail of the inner cavity (1) is provided with an inner cavity exhaust filter (2), a first high-precision closed-loop control instrument (3), a first sensor (4), a first PID (5), a first analog quantity meter (6), an inner cavity electric regulating valve (7), and an inner cavity flow meter (8), which are connected in sequence; the tail of the outer cavity (9) is provided with an outer cavity exhaust filter (10), a second high-precision closed-loop control instrument (11), a second sensor (12), a second PID (13), a second analog quantity meter (14), an outer cavity electric regulating valve (15), and an outer cavity flow meter (16), which are connected in sequence; and a PUMP (17) is connected to the end of the inner cavity flow meter (8) and the end of the outer cavity flow meter (16).

2. A method for controlling the flow ratio between the inner and outer chambers of a MOCVD device as claimed in claim 1, characterized in that The specific steps are as follows: 1) Check whether all parts are installed properly and working properly; 2) The MOCVD equipment is started, the inner chamber (1) and the outer chamber (9) begin to work, and the gas flows therein to react; 3) The exhaust gas generated in the inner cavity (1) first passes through the inner cavity exhaust gas filter (2) to filter out impurities and particulate matter therein, and the exhaust gas generated in the outer cavity (9) passes through the outer cavity exhaust gas filter (10) to filter; 4) The filtered exhaust gas in the inner cavity (1) reaches a first high-precision closed-loop control instrument (3), which measures relevant parameters of the exhaust gas, and the filtered exhaust gas in the outer cavity (9) reaches a second high-precision closed-loop control instrument (11) for parameter measurement; 5) The first sensor (4) detects physical quantities such as the temperature of the exhaust gas in the inner cavity (1), and transmits the data to the first PID (5). The first PID (5) performs calculations based on the set temperature value and the actual temperature value detected by the first sensor (4), and outputs a control signal. The second sensor (12) detects information such as the temperature of the exhaust gas in the outer cavity (9), and transmits the information to the second PID (13); 6) The first analog quantity pair instrument (6) processes and converts the control signal output by the first PID (5), and the processed signal acts on the inner cavity electric regulating valve (7), and the regulating valve adjusts the opening according to the signal, thereby controlling the flow of the inner cavity (1). The second PID (13) performs calculations and outputs a control signal to the second analog quantity pair instrument (14). After the second analog quantity pair instrument (14) processes and converts the control signal, it acts on the outer cavity electric regulating valve (15) to control the flow of the outer cavity (9); 7) The inner cavity flow meter (8) measures the actual flow rate of the exhaust gas in the inner cavity (1) in real time and feeds the flow data back to the control system. The outer cavity flow meter (16) measures the actual flow rate of the exhaust gas in the outer cavity (9). The flow data measured by the inner cavity flow meter (8) and the outer cavity flow meter (16) are transmitted to the PUMP (17). The PUMP (17) adjusts the suction power according to the received flow data to control the flow ratio between the actual inner cavity (1) and the outer cavity (9).

3. A method for controlling the flow ratio between the inner and outer chambers of a MOCVD device as claimed in claim 2, characterized in that: When the opening degree of the outer cavity electric regulating valve (15) is 8%, the reading of the outer cavity flow meter (16) is 0.4, the degree of the inner cavity flow meter (8) is 40, and the flow ratio between the inner cavity (1) and the outer cavity (9) is 100:1; when the opening degree of the outer cavity electric regulating valve (15) is 10%, the reading of the outer cavity flow meter (16) is 0.5, the degree of the inner cavity flow meter (8) is 50, and the flow ratio between the inner cavity (1) and the outer cavity (9) is 100:1; when the opening degree of the outer cavity electric regulating valve (15) is 16%, the reading of the outer cavity flow meter (16) is 0.8, the degree of the inner cavity flow meter (8) is 80, and the flow ratio between the inner cavity (1) and the outer cavity (9) is 100:

1.

4. A method for controlling the flow ratio between the inner and outer chambers of a MOCVD device as claimed in claim 2, characterized in that: The inner cavity flow meter (8), the outer cavity flow meter (16) and the PUMP (17) are electrically connected.

5. A method for controlling the flow ratio between the inner and outer chambers of a MOCVD device as claimed in claim 2, characterized in that: The inner cavity electric regulating valve (7) is a regulating valve with a large diameter, and the outer cavity electric regulating valve (15) is a regulating valve with a small diameter.

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