MPCVD device

Abstract

The MPCVD device comprises a waveguide tube, a reaction chamber, a quartz plate, a circular substrate table, a substrate table circulating water path, an air inlet and an air outlet, the quartz plate is arranged between the opening of the top wall of the reaction chamber and the end part of the waveguide tube so as to separate the reaction chamber from the waveguide tube; the waveguide tube is used for being connected to a microwave source for generating microwaves and enabling the microwaves to penetrate through the waveguide tube and the quartz plate to be coupled into the reaction chamber, the circular substrate table is positioned in the reaction chamber, is located under the quartz plate and is separated from the quartz plate, and a substrate is arranged on the circular substrate table; the substrate table circulating water path is arranged below the circular substrate table; the gas inlet is formed in the reaction chamber; the exhaust port is arranged in the reaction chamber. The MPCVD device further comprises a plurality of heating lamps, the plurality of heating lamps are arranged on the peripheral wall of the reaction chamber around the circular substrate table in multiple circles which are concentric with the circular substrate table and aligned in the vertical direction, and the heating lamps in all the circles are used for horizontally and perpendicularly heating the circular substrate table and the substrate from the peripheral side of the circular substrate table.

Description

Technical Field

[0001] The present disclosure relates to the field of film coating, and more specifically to an MPCVD device. Background Art

[0002] Diamond materials have great application potential in many fields due to their excellent physical properties. Microwave plasma chemical vapor deposition (MPCVD) technology is a method of depositing diamond films on substrates through chemical reactions under the action of microwaves. In the MPCVD process, especially for the growth of large-sized diamond films, the temperature uniformity of the substrate has an important influence on the quality of the diamond film.

[0003] Figure 1 The existing MPCVD device 100' comprises a waveguide 1', a reaction chamber 2', a quartz plate 3', a circular substrate stage 4', a substrate stage circulation water path 5', an air inlet 6A', an exhaust port 6B', a lifting component 9' and a plurality of thermocouples 10'.

[0004] The quartz plate 3' is arranged as a microwave dielectric window between the opening 211' of the top wall 21' of the reaction chamber 2' and the end of the waveguide 1', so as to close the opening 211' of the top wall 21' of the reaction chamber 2' and thereby separate the reaction chamber 2' from the waveguide 1'. The waveguide 1' is used to be connected to a microwave source (not shown) that generates microwaves and couple the microwaves into the reaction chamber 2' through the waveguide 1' and the quartz plate 3'. The circular substrate stage 4' is positioned in the reaction chamber 2', directly below the quartz plate 3' and separated from the quartz plate 3', and the circular substrate stage 4' is provided with a substrate 300 on which a diamond film is to be deposited by microwave plasma chemical vapor deposition. The substrate stage circulation water circuit 5' is arranged below the circular substrate stage 4', and the substrate stage circulation water circuit 5 is used to control the temperature of the circular substrate stage 4' from below. The air inlet 6A is provided in the reaction chamber 2, and the air inlet 6A' is used to pass the reaction gas for forming the diamond film into the reaction chamber 2'. The exhaust port 6B' is provided in the reaction chamber 2', and is used to form a flowing vacuum in the reaction chamber 2' and continuously exhaust together with the air inlet 6A'. The lifting component 9' is provided to seal and penetrate the bottom wall 23' of the reaction chamber 2', and the lifting component 9' is connected to the substrate stage circulating water circuit 5' from below, and the lifting component 9' is used to lift the substrate stage circulating water circuit 5' and the circular substrate stage 4' to adjust the interval between the circular substrate stage 4' and the quartz plate 3'. The multiple thermocouples 10' are insulated and pass through the lifting component 9', the substrate stage circulating water circuit 5' and the circular substrate stage 4' to measure the temperature of the substrate 300 on the circular substrate stage 4'.

[0005] In the existing MPCVD device 100', the temperature of the circular substrate stage 4' and the substrate 300 only depends on the microwave plasma 400 (also called glow) ignited on the substrate 300. Due to the uneven distribution of plasma density, the temperature gradient of the substrate 300 is large, and it is difficult to achieve uniform temperature distribution of the substrate 300, which easily causes uneven crystal quality and local defects in the diamond film during the growth process, thereby affecting the performance and application of the device made of the substrate with the diamond film. Utility Model Content

[0006] In view of the problems existing in the background technology, an object of the present disclosure is to provide an MPCVD device, which can improve the temperature distribution of the substrate and thus improve the uniformity of the growth of the diamond film.

[0007] Thus, an MPCVD device includes a waveguide, a reaction chamber, a quartz plate, a circular substrate stage, a substrate stage circulation water path, an air inlet, and an exhaust port; the quartz plate is arranged between the opening of the top wall of the reaction chamber and the end of the waveguide as a microwave dielectric window to close the opening of the top wall of the reaction chamber and thereby separate the reaction chamber from the waveguide; the waveguide is used to be connected to a microwave source that generates microwaves and couple the microwaves into the reaction chamber through the waveguide and the quartz plate; the circular substrate stage is positioned in the reaction chamber, directly below the quartz plate and separated from the quartz plate; the circular substrate stage is for a substrate to be deposited with a diamond film by microwave plasma chemical vapor deposition to be placed thereon; the substrate stage circulation water path is arranged below the circular substrate stage, and the substrate stage circulation water path is used to control the temperature of the circular substrate stage from below; the air inlet is arranged in the reaction chamber, and the air inlet is used to pass the reaction gas for forming the diamond film into the reaction chamber; the exhaust port is arranged in the reaction chamber, and is used to form a flowing vacuum in the reaction chamber together with the air inlet and to exhaust continuously. The MPCVD device also includes a plurality of heating lamps, which are arranged on the peripheral wall of the reaction chamber in a plurality of circles around the circular substrate stage in an up-and-down direction concentric with the circular substrate stage. The heating lamps in each circle are used for directly heating the circular substrate stage and the substrate horizontally from the peripheral side of the circular substrate stage.

[0008] The beneficial effects of the present disclosure are as follows: compared with the MPCVD device in the background technology, in the MPCVD device according to the present disclosure, a plurality of heating lamps are used as auxiliary heating sources for performing horizontal direct heating on the circular substrate stage and the substrate from the entire circumference of the circular substrate stage and the substrate. The heat provided by the plurality of heating lamps is combined with the heat generated by the microwave plasma, which can effectively improve the temperature distribution of the substrate, thereby improving the uniformity of the diamond growth film. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a schematic diagram of the structure of an existing MPCVD device.

[0010] Figure 2 It is a schematic diagram of the structure of the MPCVD device according to the present disclosure.

[0011] Figure 3 yes Figure 2 A schematic cross-sectional view of the layout of a circle of multiple heating lamps in an MPCVD device and the peripheral wall of the reaction chamber.

[0012] The reference numerals are described as follows:

[0013] 100'MPCVD device100MPCVD device

[0014] 1' waveguide 1 waveguide

[0015] 2' reaction chamber 2 reaction chamber

[0016] 21' top wall 21 top wall

[0017] 211' opening 211 opening

[0018] 22' surrounding wall 22 surrounding wall

[0019] 23' bottom wall 23' bottom wall

[0020] 3' Quartz Plate 3 Quartz Plate

[0021] 4' round substrate table 4 round substrate table

[0022] 5' substrate table circulating water circuit 5 substrate table circulating water circuit

[0023] 6A' Air Inlet 6A' Air Inlet

[0024] 6B' Exhaust Port 6B Exhaust Port

[0025] 9' lifting part 7 heating lamp

[0026] 10' Thermocouple 8 Circulating Water Loop

[0027] 300 substrate 9 lifting component

[0028] 400 plasma 10 thermocouples DETAILED DESCRIPTION

[0029] The accompanying drawings show embodiments of the present disclosure, and it will be understood that the disclosed embodiments are merely examples of the present disclosure, and the present disclosure can be implemented in various forms. Therefore, the specific details disclosed herein should not be interpreted as limiting, but merely as the basis for the claims and as a representative basis for teaching ordinary technicians in the field to implement the present disclosure in various ways.

[0030] [MPCVD equipment]

[0031] Figure 2 It is a schematic diagram of the structure of the MPCVD device according to the present disclosure. Figure 3 yes Figure 2 A schematic cross-sectional view of the layout of a circle of multiple heating lamps in an MPCVD device and the peripheral wall of the reaction chamber.

[0032] Reference Figure 2 and Figure 3 According to the present disclosure, the MPCVD device 100 includes a waveguide 1, a reaction chamber 2, a quartz plate 3, a circular substrate stage 4, a substrate stage circulation water channel 5, an air inlet 6A, an exhaust port 6B, and a plurality of heating lamps 7.

[0033] The quartz plate 3 is arranged as a microwave dielectric window between the opening 211 of the top wall 21 of the reaction chamber 2 and the end of the waveguide 1 to close the opening 211 of the top wall 21 of the reaction chamber 2 and separate the reaction chamber 2 from the waveguide 1. The waveguide 1 is used to connect to a microwave source (not shown) that generates microwaves and couple the microwaves into the reaction chamber 2 through the waveguide 1 and the quartz plate 3. The circular substrate stage 4 is positioned in the reaction chamber 2, directly below the quartz plate 3 and separated from the quartz plate 3, and the circular substrate stage 4 is provided with a substrate 300 to be deposited with a diamond film by microwave plasma chemical vapor deposition. The substrate stage circulation water circuit 5 is arranged below the circular substrate stage 4, and the substrate stage circulation water circuit 5 is used to control the temperature of the circular substrate stage 4 from below. The air inlet 6A is arranged in the reaction chamber 2, and the air inlet 6A is used to pass the reaction gas for forming the diamond film into the reaction chamber 2. The exhaust port 6B is provided in the reaction chamber 2, and is used to form a flowing vacuum and continuously exhaust gas in the reaction chamber 2 together with the air inlet 6A. The plurality of heating lamps 7 are provided on the peripheral wall 22 of the reaction chamber 2 in a plurality of circles aligned in the vertical direction concentric with the circular substrate stage 4, surrounding the circular substrate stage 4. The heating lamps 7 in each circle are used to heat the circular substrate stage 4 and the substrate 300 horizontally and directly from the peripheral side of the circular substrate stage 4.

[0034] Compared with the MPCVD device 100' in the background technology, in the MPCVD device 100 according to the present disclosure, a plurality of heating lamps 7 are used as auxiliary heating sources for performing horizontal direct heating on the circular substrate stage 4 and the substrate 300 from the entire circumference of the circular substrate stage 4 and the substrate 300. The heat provided by the plurality of heating lamps 7 is combined with the heat generated by the microwave plasma 400, which can effectively improve the temperature distribution of the substrate 300, thereby improving the uniformity of the diamond growth film.

[0035] Note that, Figure 1 and Figure 2 The difference between the MPCVD device 100 according to the present disclosure and the known MPCVD device 100 ′ lies in the multiple heating lamps 7 and the circulating water loop 8 matched with the multiple heating lamps 7 described later.

[0036] In the MPCVD device 100 according to the present disclosure, the arrangement of the gas inlet 6A is preferably to ensure the uniformity of the gas inlet. For example, the gas inlet 6A is arranged in multiples, and the multiple gas inlets 6A are arranged in a ring around the circular substrate stage 4 and the substrate 300 at equal intervals. The gas inlet 6A can be arranged on the peripheral wall 22 of the reaction chamber 2, or on the top wall 21 of the reaction chamber 2. The exhaust port 6B is usually arranged at the bottom of the MPCVD device 100, for example, the exhaust port 6B is arranged on the bottom wall 23 of the reaction chamber 2, or the exhaust port 6B is arranged at the bottom of the peripheral wall 22 of the reaction chamber 2.

[0037] like Figure 2 and Figure 3 As shown, in one example, the plurality of heating lamps 7 are arranged around the circular substrate stage 4 in four circles aligned in the vertical direction, the heating lamps 7 in the bottom circle are used to directly heat the circular substrate stage 4 horizontally but are separated from the substrate stage circulation water path 5 in the vertical direction; the heating lamps 7 in the top circle are used to directly heat the space above the substrate 300 on the circular substrate stage 4 horizontally. Further, the heating lamps 7 on each circle are arranged at equal intervals. In one example, the number of heating lamps 7 on each circle is the same. For example, there are 16 heating lamps 7 on each circle. In one example, the power range of the heating lamps 7 in each circle is 0-3000W. The heating lamps 7 may be halogen lamps.

[0038] like Figure 2 and Figure 3 As shown, in one example, the MPCVD device 100 further includes a circulating water loop 8, which is disposed on the peripheral wall 22 of the reaction chamber 2 and radially outside the plurality of heating lamps 7, and is used to control the temperature of the peripheral wall 22 of the reaction chamber 2. Figure 2 In the embodiment, the range of the circulating water circuit 8 in the vertical direction covers the plurality of circles of the plurality of heating lamps 7 aligned in the vertical direction.

[0039] like Figure 2 As shown, in one example, the MPCVD device 100 also includes a lifting component 9, which is sealed and penetrates the bottom wall 23 of the reaction chamber 2. The lifting component 9 is connected to the substrate stage circulating water channel 5 from below. The lifting component 9 is used to lift the substrate stage circulating water channel 5 and the circular substrate stage 4 to adjust the interval between the circular substrate stage 4 and the quartz plate 3.

[0040] like Figure 2As shown, in one example, the MPCVD device 100 also includes at least three thermocouples 10, and the at least three thermocouples 10 are thermally insulated and pass through the lifting component 9, the substrate stage circulation water channel 5 and the circular substrate stage 4 to measure the temperature of the substrate 300 on the circular substrate stage 4; one of the thermocouples 10 is used to pass through the center of the top surface of the circular substrate stage 4 to measure the temperature of the substrate 300; one of the thermocouples 10 is used to pass through 2 / 5R of the top surface of the circular substrate stage 4 (where R is the radius of the circular substrate stage 4) to measure the temperature of the substrate 300; one of the thermocouples 10 is used to pass through 4 / 5R of the top surface of the circular substrate stage 4 to measure the temperature of the substrate 300.

[0041] [test]

[0042] Comparative Example 1

[0043] Comparative Example 1 is used to test the case where only a plurality of heating lamps 7 are used for heating.

[0044] The specific structure of the MPCVD device 100 used in Comparative Example 1 is as follows.

[0045] With the help of Figure 2The MPCVD device 100 used in Comparative Example 1 includes a waveguide 1, a reaction chamber 2, a quartz plate 3, a circular substrate stage 4, a substrate stage circulating water path 5, an air inlet 6A, an exhaust port 6B, a plurality of heating lamps 7, a circulating water loop 8, a lifting component 9, and a thermocouple 10. The quartz plate 3 is arranged between the opening 211 of the top wall 21 of the reaction chamber 2 and the end of the waveguide 1 as a microwave dielectric window to close the opening 211 of the top wall 21 of the reaction chamber 2 and thereby separate the reaction chamber 2 from the waveguide 1. The waveguide 1 is used to connect to a microwave source (not shown) that generates microwaves and couple the microwaves into the reaction chamber 2 through the waveguide 1 and the quartz plate 3. The circular substrate stage 4 is positioned in the reaction chamber 2, directly below the quartz plate 3 and separated from the quartz plate 3. The substrate stage circulating water path 5 is arranged below the circular substrate stage 4, and the substrate stage circulating water path 5 is used to control the temperature of the circular substrate stage 4 from below. The air inlet 6A is provided on the peripheral wall 22 of the reaction chamber 2, and is provided in 12 rings at equal intervals around the circular substrate stage 4. The exhaust port 6B is provided on the bottom wall 23 of the reaction chamber 2. The plurality of heating lamps 7 are provided on the peripheral wall 22 of the reaction chamber 2 in four circles aligned in the vertical direction concentric with the circular substrate stage 4 around the circular substrate stage 4, and the heating lamps 7 in each circle are used to heat the circular substrate stage 4 and the substrate 300 horizontally and directly from the peripheral side of the circular substrate stage 4. The heating lamps 7 in the lowest circle are used to heat the circular substrate stage 4 horizontally and directly, but are separated from the substrate stage circulation water path 5 in the vertical direction; the heating lamps 7 in the highest circle are used to heat the space above the substrate 300 on the circular substrate stage 4 horizontally and directly. The heating lamps 7 on each circle are arranged at equal intervals. There are 16 heating lamps 7 on each circle. Each heating lamp 7 is a halogen lamp with a rated power of 150W, and the power of the halogen lamp is adjusted by the current supplied by the connected power supply. The circulating water loop 8 is arranged on the peripheral wall 22 of the reaction chamber 2 and is located radially outside the plurality of heating lamps 7, and is used to control the temperature of the peripheral wall 22 of the reaction chamber 2. The range of the circulating water loop 8 in the vertical direction covers four circles of the plurality of heating lamps 7 aligned in the vertical direction. Three thermocouples 10 are used; the thermocouples 10 are heat-insulated and pass through the lifting component 9, the substrate stage circulating water path 5 and the circular substrate stage 4 to measure the temperature of the substrate 300 on the circular substrate stage 4, one of the thermocouples 10 is used to pass through the center of the top surface of the circular substrate stage 4 to measure the temperature of the substrate 300, one of the thermocouples 10 is used to pass through 2 / 5R of the top surface of the circular substrate stage 4 to measure the temperature of the substrate 300, and one of the thermocouples 10 is used to pass through 4 / 5R of the top surface of the circular substrate stage 4 to measure the temperature of the substrate 300.

[0046] During operation, a silicon wafer substrate 300 is placed on the circular substrate stage 4, and the diameter of the substrate 300 is larger than 4 / 5R of the circular substrate stage 4 but smaller than R (i.e., radius) of the circular substrate stage 4. The lifting component 9 adjusts the substrate 300 on the circular substrate stage 4 to a height of 200 mm away from the quartz plate 3. The substrate stage circulating water circuit 5 and the circulating water circuit 8 are turned on, and the microwave source is not turned on. The reaction chamber 2 is first evacuated to 10 KPa through the air inlet 6A and the exhaust port 6B, and then hydrogen is introduced through the air inlet 6A. The total flow rate of hydrogen in all the air inlets 6A is 500 sccm. The pressure of the reaction chamber 2 is maintained at 10 KPa through the air inlet 6A and the exhaust port 6B; thereafter, the four circles of heating lamps 7 are turned on to preheat the circular substrate stage 4 for 5 minutes, wherein the power of the four circles of heating lamps 7 is 1000 W through current adjustment; after preheating for 5 minutes, the temperature of the substrate 300 on the circular substrate stage 4 is measured by three thermocouples 10, and the temperatures of the substrate 300 at the center of the circular substrate stage 4, at 2 / 5R of the circular substrate stage 4 and at 4 / 5R of the circular substrate stage 4 are measured to be 175.2°C, 180.5°C and 186.1°C, respectively.

[0047] Based on the test of comparative example 1, it is explained that by setting up multiple circles of heating lamps 7, the temperature of the substrate 300 is low in the center and high at the edge.

[0048] Comparative Example 2

[0049] Comparative Example 2 was used to test the case of microwave plasma heating only.

[0050] The structure of the MPCVD device 100 of comparative example 1 is adopted, the same substrate 300 is placed, and the lifting component 9 is adjusted to the same distance.

[0051] The difference from Example 1 during operation is that the heating lamp 7 is not turned on, the substrate table circulating water circuit 5 is turned on, and the circulating water loop 8 is not turned on. The reaction chamber 2 is first evacuated to below 0.1 Pa through the air inlet 6A and the exhaust port 6B, and hydrogen is introduced through the air inlet 6A. The total flow rate of all the air inlets 6A is 500 sccm. At the same time, the microwave source is turned on, and the microwave power of the microwave source and the chamber pressure of the reaction chamber 2 are slowly increased. The pressure of the reaction chamber 2 is controlled at 20 KPa. The microwave power is controlled in real time by the temperatures measured by the three thermocouples 10. The temperatures of the substrate 300 measured by the three thermocouples 10 are 871.7°C (0 / 5R position), 866.1°C (2 / 5R position) and 860.5°C (4 / 5R position), respectively. The temperature at the 0 / 5R position differs from the temperature at the 4 / 5 position by more than 10°C, and the temperature of the heated substrate 300 is high in the center and low at the edge.

[0052] Example 1

[0053] Example 1 is used to test the situation where multiple heating lamps 7 and microwave plasma are heated together.

[0054] The same MPCVD device 100 structure as in Comparative Example 1 is used, the same substrate 300 is placed, and the lifting component 9 is adjusted to the same distance.

[0055] The difference between the operation and the comparative example 1 is that the microwave source is not turned on, the substrate stage circulating water circuit 5 and the circulating water circuit 8 are turned on, the reaction chamber 2 is first evacuated to below 0.1 Pa through the air inlet 6A and the exhaust port 6B, the power of the heating lamp per circle is adjusted to 200W, and the circular substrate stage 4 and the substrate 300 are preheated for 5 minutes; after the preheating is completed, hydrogen is introduced through the air inlet 6A, and the total flow rate of all the air inlets 6A is 500sccm, and the microwave source is turned on at the same time, and the microwave power of the microwave source and the cavity of the reaction chamber 2 are slowly increased. The chamber pressure, microwave power is added to 3000W, the pressure of the reaction chamber 2 is controlled at 20KPa, and the temperatures measured by the three thermocouples 10 are used to adjust the microwave power and the power of each circle of heating lamps 7 in real time to ensure the uniformity of the temperature of the substrate 300. The temperatures measured by the three thermocouples 10 are 871.5℃ (0 / 5R position), 868.5℃ (2 / 5R position) and 871.8 (4 / 5R position), respectively, so that the temperature of the substrate 300 measured by the three thermocouples 10 can reach 870±2℃.

[0056] Based on the test of Example 1 and compared with Comparative Example 2, it is shown that the uniform heating of the substrate 300 can be achieved through the cooperation of the multi-circle heating lamp 7 and the microwave power.

[0057] Example 2

[0058] Example 2 is used to test the diamond coating process under auxiliary heating by multiple heating lamps 7 .

[0059] The structure of the MPCVD device 100 of comparative example 1 is adopted, the same substrate 300 is placed, and the lifting component 9 is adjusted to the same distance.

[0060] Before being placed on the circular substrate stage 4, the substrate 300 is cleaned and pickled using an acid solution formed by 65% ​​concentrated nitric acid and 98% concentrated sulfuric acid in a volume ratio of 3:1. The temperature of the acid solution is set to 190°C and the pickling time is 25 minutes. After the pickling treatment, the single crystal substrate is placed in ionized water for ultrasonic cleaning, and then ultrasonic cleaning is performed alternately using 95% concentration alcohol and acetone. Each cleaning time is 5 minutes, and the cleaning is performed three times in a row.

[0061] During operation:

[0062] The cleaned substrate 300 is placed on the circular substrate stage 4, the microwave source is not turned on, the substrate stage circulating water circuit 5 and the circulating water loop 8 are turned on, the reaction chamber 2 is first evacuated to below 0.1 Pa through the air inlet 6A and the exhaust port 6B, the power of the heating lamp 7 per circle is adjusted to 200 W, and the circular substrate stage 4 and the substrate 300 are preheated for 5 minutes;

[0063] After the preheating is completed, hydrogen is introduced through the air inlet 6A, and the total hydrogen flow rate of all the air inlets 6A is 500 sccm. At the same time, the microwave source is turned on, and the microwave power of the microwave source and the chamber pressure of the reaction chamber 2 are slowly increased. The pressure of the reaction chamber 2 is controlled at 20 KPa;

[0064] After the deposition temperature of the substrate 300 is reached, reactant gases methane and hydrogen are introduced through the gas inlet 6A, the deposition temperature is 900° C., the volume flow ratio of methane to hydrogen is 1:10, and the diamond film is deposited. The temperatures of different areas of the substrate 300 of the circular substrate stage 4 are monitored in real time by three thermocouples 10. The microwave power and the power of each circle of heating lamps 7 are adjusted in real time by the temperatures measured by the three thermocouples 10, so that the temperatures of the substrate 300 on the annular substrate stage 4 measured by the three thermocouples 10 tend to be consistent and remain stable until the deposition is completed;

[0065] After the deposition is completed, the microwave power is gradually reduced, and the power of the heating lamp 7 is adjusted and the temperature of different positions of the substrate 300 is monitored by three thermocouples 10, and the temperature is slowly lowered. After cooling, the grown diamond is taken out;

[0066] Measuring the uniformity of the grown diamond films.

[0067] Comparative Example 3

[0068] The structure of the MPCVD device 100 of comparative example 1 is adopted, the same substrate 300 is placed, and the lifting component 9 is adjusted to the same distance.

[0069] Before the substrate 300 is placed on the circular substrate stage 4, the cleaning process is performed in the same manner as in Example 2.

[0070] During operation:

[0071] The cleaned substrate 300 is placed on the circular substrate stage 4, the microwave source is turned off, the substrate stage circulating water circuit 5 is turned on, the circulating water loop 8 is turned off, and all the heating lamps 7 are turned off, and the reaction chamber 2 is first evacuated to below 0.1 Pa through the air inlet 6A and the exhaust port 6B;

[0072] After the preheating is completed, hydrogen is introduced through the air inlet 6A, and the total hydrogen flow rate of all the air inlets 6A is 500 sccm. At the same time, the microwave source is turned on, and the microwave power of the microwave source and the chamber pressure of the reaction chamber 2 are slowly increased. The pressure of the reaction chamber 2 is controlled at 20 KPa;

[0073] After the deposition temperature of the substrate 300 is reached, reactant gases methane and hydrogen are introduced through the gas inlet 6A, the deposition temperature is 900° C., the volume flow ratio of methane to hydrogen is 1:10, and the diamond film is deposited. The temperatures of different regions of the substrate 300 of the circular substrate stage 4 are monitored in real time by three thermocouples 10. The microwave power is adjusted in real time in the same manner as in Example 3 by the temperatures measured by the three thermocouples 10, so that the temperatures of the substrate 300 on the annular substrate stage 4 measured by the three thermocouples 10 are as close to the same as those of Example 3, and remain stable until the deposition is completed;

[0074] After the deposition is completed, the microwave power is gradually reduced, and the power of the heating lamp 7 is adjusted and the temperature of different positions of the substrate 300 is monitored by three thermocouples 10, and the temperature is slowly lowered. After cooling, the grown diamond is taken out;

[0075] Measuring the uniformity of the grown diamond films.

[0076] The uniformity of the grown diamond film measured in Example 3 is 3.4%, and the uniformity of the grown diamond film measured in Comparative Example 2 is 9.8%, which differs by 6.4%. The uniformity refers to the uniformity of the grown thickness. The thickness of the diamond film on the substrate 300 is measured at 49 points by a spiral micrometer (i.e., the overall thickness minus the thickness of the substrate 300), and the uniformity of the thickness of the diamond film is calculated by the variance method.

[0077] The above detailed description is used to describe multiple exemplary embodiments, but this document is not intended to be limited to the explicitly disclosed combinations. Therefore, unless otherwise stated, the various features disclosed herein can be combined together to form multiple additional combinations that are not shown for the sake of simplicity.

Claims

1. An MPCVD device, comprising a waveguide (1), a reaction chamber (2), a quartz plate (3), a circular substrate stage (4), a substrate stage circulation water path (5), an air inlet (6A), and an exhaust port (6B); A quartz plate (3) is arranged as a microwave dielectric window between an opening (211) of a top wall (21) of a reaction chamber (2) and an end of a waveguide (1) to close the opening (211) of the top wall (21) of the reaction chamber (2) and thereby separate the reaction chamber (2) and the waveguide (1); The waveguide (1) is used to connect to a microwave source that generates microwaves and couple the microwaves into the reaction chamber (2) through the waveguide (1) and the quartz plate (3). The circular substrate stage (4) is positioned in the reaction chamber (2), directly below the quartz plate (3) and spaced apart from the quartz plate (3), and the circular substrate stage (4) is used to place a substrate (300) on which a diamond film is to be deposited by microwave plasma chemical vapor deposition; The substrate stage circulation water circuit (5) is arranged below the circular substrate stage (4), and the substrate stage circulation water circuit (5) is used to control the temperature of the circular substrate stage (4) from below; An air inlet (6A) is arranged in the reaction chamber (2), and the air inlet (6A) is used to pass reaction gas for forming a diamond film into the reaction chamber (2); The exhaust port (6B) is arranged in the reaction chamber (2) and is used to form a flowing vacuum in the reaction chamber (2) together with the air inlet (6A) and to exhaust the air continuously; It is characterized in that The MPCVD device (100) further includes a plurality of heating lamps (7), The plurality of heating lamps (7) are arranged on the peripheral wall (22) of the reaction chamber (2) in a plurality of circles around the circular substrate stage (4) in a vertical direction aligned concentrically with the circular substrate stage (4). The heating lamps (7) in each circle are used to directly heat the circular substrate stage (4) and the substrate (300) horizontally from the circumference of the circular substrate stage (4).

2. The MPCVD device according to claim 1, characterized in that: The plurality of heating lamps (7) are arranged in four circles aligned in the vertical direction around the circular substrate stage (4). The heating lamps (7) in the lowest circle are used to directly heat the circular substrate table (4) horizontally but are separated from the substrate table circulation water path (5) in the vertical direction; The uppermost circle of heating lamps (7) is used to directly heat the space above the substrate (300) on the circular substrate stage (4) horizontally.

3. The MPCVD device according to claim 1, characterized in that: The heating lamps (7) on each circle are arranged at equal intervals.

4. The MPCVD device according to claim 3, characterized in that: The number of heating lamps (7) on each circle is the same; There are 16 heating lamps (7) on each circle.

5. The MPCVD device according to claim 4, characterized in that: The heating lamp (7) is a halogen lamp.

6. The MPCVD device according to claim 1, characterized in that: The MPCVD device (100) further comprises a circulating water loop (8), The circulating water loop (8) is arranged on the peripheral wall (22) of the reaction chamber (2) and is located radially outside the plurality of heating lamps (7) and is used to control the temperature of the peripheral wall (22) of the reaction chamber (2).

7. The MPCVD device according to claim 6, characterized in that: The circulating water circuit (8) also covers a plurality of circles of the plurality of heating lamps (7) aligned in the vertical direction in a range in the vertical direction.

8. The MPCVD device according to claim 1, characterized in that: The MPCVD device (100) further includes a lifting component (9), The lifting component (9) is sealed and penetrates the bottom wall (23) of the reaction chamber (2). The lifting component (9) is connected to the substrate stage circulation water path (5) from below. The lifting component (9) is used to lift the substrate stage circulation water path (5) and the circular substrate stage (4) to adjust the interval between the circular substrate stage (4) and the quartz plate (3).

9. The MPCVD device according to claim 1, characterized in that: The MPCVD device (100) further comprises at least three thermocouples (10), The at least three thermocouples (10) are thermally insulated and pass through the lifting component (9), the substrate stage circulation water path (5) and the circular substrate stage (4) to measure the temperature of the substrate (300) on the circular substrate stage (4); One of the thermocouples (10) is used to measure the temperature of the substrate (300) through the center of the top surface of the circular substrate stage (4); One of the thermocouples (10) is used to measure the temperature of the substrate (300) through 2 / 5R of the top surface of the circular substrate stage (4); One of the thermocouples (10) is used to measure the temperature of the substrate (300) through 4 / 5R of the top surface of the circular substrate stage (4).

Images