A device and method for adjusting a diamond growth temperature field in situ

Abstract

The application provides a device and a method for adjusting a diamond growth temperature field in situ, and relates to the field of diamond growth temperature field regulation and control.The device comprises a liftable fixing table, the fixing table comprises a side wall and a cavity surrounded by the side wall, the inside of the cavity is provided with a liftable cooling table, the inside of the side wall and the inside of the cooling table are respectively connected to an external cooling circuit;the inside of the cavity is further provided with an adjusting table, the adjusting table is located above the cooling table, the adjusting table comprises an upper step and a middle step located below the upper step;the top of the fixing table is provided with a support, the bottom of the support is not closed, a substrate holder is arranged on the support, and a substrate is arranged on the substrate holder.In the process of large-size single crystal / multicrystal growth, annealing and the like, the application can realize in-situ stable temperature field and reduce temperature difference, thereby reducing the internal stress of large-size diamond and improving the growth yield.

Description

Technical Field

[0001] This invention relates to the field of diamond growth temperature field control, and in particular to a device and method for in-situ control of diamond growth temperature field. Background Technology

[0002] In MPCVD equipment, temperature is one of the key parameters affecting diamond growth. A suitable temperature range promotes diamond growth, while temperatures exceeding the rated range are detrimental. However, in actual MPCVD diamond growth, due to inconsistencies in plasma shape and material ionization deposition rate, uneven temperature fields are often encountered in the diamond deposition area under variations in power, gas pressure, and gas flow rate. This results in inconsistent diamond growth environments in different regions, leading to uneven thickness, high internal stress, and reduced growth yield. Furthermore, during the growth process and subsequent annealing, temperature field variations caused by changes in power, gas pressure, and diamond thickness can create significant temperature differences between the inner and outer rings.

[0003] The common method for controlling the growth temperature is to place the molybdenum growth stage directly on a water-cooled platform and machine a series of channels of varying thicknesses and shapes onto the stage to adjust local heat conduction and thus influence the growth temperature. This method has significant drawbacks: the operation is cumbersome, the molybdenum stage has a complex structure and requires a large amount of machining, leading to wasted molybdenum material; furthermore, the channel depth is fixed and statically preset, making it difficult to flexibly adjust the temperature at each stage of the growth process. Summary of the Invention

[0004] To address the aforementioned problems, the first aspect of this invention provides an in-situ device for regulating the temperature field during diamond growth. This device can achieve an in-situ stable temperature field and reduce temperature differences during large-size single / polycrystalline growth, annealing, and other processes, thereby reducing internal stress in large-size diamonds and improving growth yield.

[0005] The device for in-situ adjustment of the temperature field for diamond growth provided by the present invention includes: a liftable fixed platform, the fixed platform including a side wall and a cavity surrounded by the side wall, the cavity having a liftable cooling platform inside, and the interior of the side wall and the interior of the cooling platform being connected to an external cooling circuit respectively; the cavity also having an adjustment platform inside, the adjustment platform being located above the cooling platform, the adjustment platform including an upper step and a middle step located below the upper step; a support is provided on the top of the fixed platform, the bottom of the support is not closed, a substrate holder is provided on the support, the substrate holder is used to support the substrate, and the substrate is used for diamond deposition.

[0006] In one feasible embodiment, the adjustment platform further includes a lower step located below the middle step, wherein the diameters of the lower step, the middle step, and the upper step decrease sequentially.

[0007] In one possible embodiment, the support includes an upper edge step located at the top of the support, the upper edge step being connected to the top of the fixed platform.

[0008] In one feasible embodiment, the bracket further includes a lower edge step located at the bottom of the bracket, the lower edge step extending in the opposite direction to the upper edge step, and the inner diameter of the lower edge step being not less than the outer diameter of the middle step.

[0009] In one feasible embodiment, the bottom of the substrate holder is provided with a bottom groove, the diameter of which is not less than the diameter of the upper step.

[0010] In one possible embodiment, the top of the substrate holder is provided with a top groove for supporting the substrate.

[0011] In one feasible embodiment, the material of the substrate is selected from any one of non-metallic wafers such as silicon wafers, diamond single crystals or multi-crystal wafers, silicon carbide wafers, gallium nitride wafers, or high-temperature resistant metals and alloys such as molybdenum wafers and tungsten wafers; and / or, the material of the substrate holder is selected from any one of metals or alloys such as molybdenum, copper, stainless steel, tungsten, nickel, titanium, niobium, and tantalum.

[0012] In one feasible embodiment, the material of the support is selected from any one of molybdenum, copper, stainless steel, tungsten, nickel, titanium, niobium, tantalum or alloys, and preferably, the support is a solid structure.

[0013] A second aspect of the present invention provides a method for in-situ conditioning of the temperature field during diamond growth, employing the apparatus for in-situ conditioning of the temperature field during diamond growth as provided in the first aspect of the present invention, comprising:

[0014] Raise the cooling platform, and adjust the top of the platform to gradually contact the bottom of the substrate holder to form the first stage of heat dissipation;

[0015] Optionally, the cooling stage is raised, and the top of the stage pushes the substrate holder upward and gradually away from the support, raising the relative position of the stage with respect to the fixed stage; at the same time, the fixed stage gradually moves downward, lowering the absolute position of the substrate, thereby keeping the substrate in place and forming a second stage of heat dissipation.

[0016] Alternatively, the cooling stage can be raised so that the relative position of the adjusting stage with respect to the fixed stage is raised, and the side wall of the middle step contacts the inner wall of the support; at the same time, the fixed stage gradually moves downward so that the absolute position of the substrate is lowered, thereby keeping the substrate in place and forming a third stage of heat dissipation.

[0017] In one feasible embodiment, during the first-stage heat dissipation, second-stage heat dissipation, and third-stage heat dissipation processes, when the temperature of the central region of the substrate is lower than that of the edge region, the cooling stage is lowered, thereby reducing the relative position of the adjusting stage with respect to the fixed stage. During the second-stage and third-stage heat dissipation processes, while the cooling stage is lowered, the fixed stage gradually moves upward, causing the absolute position of the substrate support to rise, thereby keeping the substrate in its original position.

[0018] In one feasible embodiment, the height of the relative displacement limit between the substrate holder and the support is such that the lower surface of the substrate holder does not exceed the upper surface of the support.

[0019] The device and method for in-situ regulating the temperature field of diamond growth provided by the present invention have the following beneficial effects: the present invention can achieve an in-situ stable temperature field and reduce temperature difference during large-size single crystal / polycrystalline growth, annealing and other processes, thereby reducing the internal stress of large-size diamonds and improving the growth yield. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure in the initial state of an embodiment of the present invention.

[0021] Figure 2 This is a schematic diagram of the parameters in an embodiment of the present invention.

[0022] Figure 3 This is a schematic diagram of the overall structure for implementing the first-stage heat dissipation in an embodiment of the present invention.

[0023] Figure 4 This is a schematic diagram of the overall structure for implementing the second-stage heat dissipation in an embodiment of the present invention.

[0024] Figure 5 This is a schematic diagram of the overall structure for implementing the third-stage heat dissipation in an embodiment of the present invention.

[0025] Figure Labels

[0026] Fixed platform 1

[0027] Side wall 1-1

[0028] Cavity 1-2

[0029] Cooling Platform 2

[0030] Adjustment table 3

[0031] Climbing Step 3-1

[0032] Middle Step 3-2

[0033] 3-3 steps down

[0034] Bracket 4

[0035] Upper edge step 4-1

[0036] Lower edge step 4-2

[0037] Substrate holder 5

[0038] Top groove 5-1

[0039] Bottom groove 5-2

[0040] Substrate 6 Detailed Implementation

[0041] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. In the description of the present invention, it should be noted that the terms "left side", "right side", "upper side", "lower side", "above", "below", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying 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, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0042] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0043] Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0044] This invention provides a device for in-situ adjustment of the temperature field during diamond growth, such as... Figures 1-3As shown, it includes: a liftable fixed platform 1, which includes a side wall 1-1 and a cavity 1-2 surrounded by the side wall 1-1. The bottom of the cavity 1-2 is usually closed so that the cavity 1-2 has only one opening at the top. A liftable cooling platform 2 is provided inside the cavity 1-2. The interior of the side wall 1-1 and the interior of the cooling platform 2 are respectively connected to an external cooling circuit. The medium in the cooling circuit can be pure water or coolant. The cooling circuit inside the side wall 1-1 and the cooling circuit inside the cooling platform 2 can be connected externally, that is, they use the same cooling circuit. The bottom of the fixed platform 1 can be equipped with a lifting component to drive the lifting of the fixed platform 1, and the bottom of the cooling platform 2 can also be equipped with a lifting component to drive the lifting of the cooling platform 2. The lifting component can be a common driving component such as a stepper motor, servo motor, DC geared motor, cylinder, or electric actuator. Preferably, a servo motor equipped with an encoder can be used to precisely adjust the lifting distance. Continuing as... Figure 1 As shown, the cavity 1-2 is further provided with an adjustment platform 3, which is located above the cooling platform 2. The adjustment platform 3 includes an upper step 3-1 and a middle step 3-2 located below the upper step 3-1. The top of the fixed platform 1 is provided with a bracket 4, and a substrate holder 5 is provided on the bracket 4. The bottom of the bracket 4 is not closed to provide objective conditions for the top of the adjustment platform 3 to contact the bottom of the substrate holder 5. The substrate holder 5 is used to support the substrate 6, and the substrate 6 is used for diamond deposition.

[0045] Furthermore, the material of the substrate 6 can be a non-metallic wafer such as silicon wafer, diamond single crystal or multi-crystal wafer, silicon carbide wafer, gallium nitride wafer, or a high-temperature resistant metal and alloy such as molybdenum wafer, tungsten wafer, etc. The thickness of the substrate 6 can be 0.5~10 mm, and the diameter of the substrate 6 can be 45~120 mm, wherein the preferred diameter is 45~100 mm.

[0046] Furthermore, such as Figure 1 As shown, the adjusting platform 3 also includes a lower step 3-3 located below the middle step 3-2. The diameters of the lower step 3-3, the middle step 3-2, and the upper step 3-1 decrease sequentially, so that the adjusting platform 3 forms a three-stage variable-diameter step. The adjusting platform 3 can be made of metals or alloys such as molybdenum, copper, stainless steel, tungsten, nickel, titanium, niobium, and tantalum.

[0047] Furthermore, the substrate 5 can be made of metals or alloys such as molybdenum, copper, stainless steel, tungsten, nickel, titanium, niobium, and tantalum. Figure 1As shown, the substrate holder 5 has a top groove 5-1 at its top and a bottom groove 5-2 at its bottom; the top groove 5-1 is used to support the sample 6. Furthermore, the bottom groove 5-2 is aligned with the upper step 3-1, allowing it to contact the upper step 3-1 during the upward movement of the adjusting platform 3. The depth of the top groove 5-1 can be 0.5~10 mm, preferably 0.5~5 mm, and the diameter of the top groove 5-1 is not less than the outer diameter of the substrate 6, ensuring that the substrate 6 can be completely placed and removed. The depth of the bottom groove 5-2 is 0.5~3 mm, preferably 0.5~1 mm, and the diameter of the bottom groove 5-2 is not less than the diameter of the upper step 3-1, ensuring that the upper step 3-1 can be completely inserted.

[0048] Furthermore, the material of the support 4 can be molybdenum, copper, stainless steel, tungsten, nickel, titanium, niobium, tantalum, or an alloy. Even further, such as... Figure 1 As shown, the bracket 4 includes an upper edge step 4-1 located at the top of the bracket 4. The upper edge step 4-1 is connected to the top of the fixing platform 1. Typically, the upper edge step 4-1 is hung on the top of the fixing platform 1 and fixedly connected by screws. The bracket 4 also includes a lower edge step 4-2 located at the bottom of the bracket 4. The lower edge step 4-2 extends in the opposite direction to the upper edge step 4-1, and the inner diameter of the lower edge step 4-2 is not less than the outer diameter of the middle step 3-2. Specifically, as... Figure 1 As shown, the bracket 4 is Z-shaped.

[0049] Table 1 shows the parameter configuration relationships between the components in the embodiments of the present invention.

[0050] Table 1

[0051] Substrate 6 diameter Ø0 / mm Adjustment table 3 maximum diameter Ø7 / mm Substrate holder 5 diameter Ø1 and support 4 inner diameter Ø3 / mm <![CDATA[Height H1 / mm of substrate holder 5]]> <![CDATA[The sinking depth of the support 4 is denoted as H2]]> Bottom groove 5-2 diameter Ø2 and upper step 3-1 diameter Ø5 / mm The inner diameter of the lower edge step 4-2 is Ø4 and the diameter of the middle step 3-2 is Ø6 / mm. <![CDATA[Height H5 of the upper step 3-1 / mm]]> <![CDATA[Height H6 of the middle bench 3-2 / mm]]> <![CDATA[Height H7 of the lower step 3-3 / mm]]> 45~70 90 Ø0+5~20 3~19 <![CDATA[H2≤H1+4]]> Ø0-5~15 Ø1 > Ø4=Ø6 > Ø2 <![CDATA[H3<H5 <![CDATA[≥H3]]> 1~3 70~95 120 Ø0+5~20 7~40 <![CDATA[H2≤H1+4]]> Ø0-15~30 Ø1 > Ø4=Ø6 > Ø2 <![CDATA[H3<H5 <![CDATA[≥H3]]> 1~3 95~120 150 Ø0+5~20 7~40 <![CDATA[H2≤H1+4]]> Ø0-20~40 Ø1 > Ø4=Ø6 > Ø2 <![CDATA[H3<H5 <![CDATA[≥H3]]> 1~3

[0052] Among them, such as Figure 2 As shown, the diameter of substrate 6 is denoted as Ø0, the diameter of substrate support 5 as Ø1, the diameter of bottom groove 5-2 as Ø2, the inner diameter of support 4 as Ø3, the inner diameter of lower edge step 4-2 as Ø4, the diameter of upper step 3-1 as Ø5, the diameter of middle step 3-2 as Ø6, and the diameter of lower step 3-3 as Ø7. The height of substrate support 5 is denoted as H1, the recess depth of support 4 as H2, the height of lower edge step 4-2 as H3, the straight-line distance from the upper surface of lower step 3-3 to the lower surface of lower edge step 4-2 as H4, the height of upper step 3-1 as H5, the height of middle step 3-2 as H6, and the height of lower step 3-3 as H7.

[0053] A second aspect of this invention also provides a method for in-situ regulating the temperature field of diamond growth, employing the apparatus for in-situ regulating the temperature field of diamond growth as provided in the first aspect of this invention. This invention is typically placed inside a growth chamber. This method primarily aims to reduce the temperature of the central region of the substrate 6, thereby reducing the temperature difference between the central region and the edge region of the substrate 6. The method includes:

[0054] Step 1) As Figure 3 As shown, the cooling platform 2 is raised, and the top of the adjusting platform 3 gradually contacts the bottom of the substrate holder 5, forming the first stage of heat dissipation. Figure 1 As shown, in the initial stage, the substrate holder 5 is completely placed in the support 4. At this time, the cooling circuit inside the side wall 1-1 carries away the heat from the edge of the substrate holder 5 through the support 4, while the adjustment stage 3 has not yet contacted the bottom of the substrate holder 5. Therefore, in the initial state, the temperature of the middle area of ​​the substrate holder 5 is higher, and the temperature of the edge area is lower, forming a large temperature difference. Figure 2 As shown, when the adjustment platform 3 gradually contacts the bottom of the substrate holder 5, the heat in the central area of ​​the substrate holder 5 will be transferred along the direction of the adjustment platform 3 and the cooling platform 2, and then carried away by the cooling circuit inside the cooling platform 2, so that the temperature in the central area of ​​the substrate holder 5 drops and the temperature difference between the central area and the edge area of ​​the substrate holder 5 decreases. This is the first stage of heat dissipation.

[0055] Step 2) Raise the cooling platform 2, and the top of the adjusting platform 3 pushes the substrate support 5 upward and gradually away from the support 4, raising the relative position of the adjusting platform 3 with respect to the fixed platform 1; simultaneously, the fixed platform 1 gradually moves downward, lowering the absolute position of the substrate 6, thereby keeping the substrate 6 in its original position and forming the second stage of heat dissipation. Figure 4 As shown, based on the first stage of heat dissipation, the cooling stage 2 is further raised, causing the substrate holder 5 to be lifted upwards by the top of the adjusting stage 3. At this point, the substrate holder 5 is not completely located within the support 4. Therefore, the cooling circuit inside the side wall 1-1 has a less effective heat dissipation effect on the edge region of the substrate holder 5 than in the initial state. This means that the temperature in the edge region of the substrate holder 5 will be higher than in the initial state, and the temperature difference between the center region and the edge region of the substrate holder 5 will further decrease. This is the second stage of heat dissipation. It should be emphasized that the absolute position refers to the absolute position within the growth chamber. That is, no matter how much the cooling stage 2 is raised, the absolute position of the substrate 6 inside the growth chamber should remain at zero.

[0056] Step 3) Raise the cooling platform 2, increasing the relative position of the adjusting platform 3 with respect to the fixed platform 1, so that the sidewall of the middle step 3-2 contacts the inner wall of the support 4; simultaneously, the fixed platform 1 gradually moves downward, lowering the absolute position of the substrate 6, thereby keeping the substrate 6 in its original position and forming the third stage of heat dissipation. Figure 5As shown, based on the second stage of heat dissipation, the cooling platform 2 is raised further, so that the substrate holder 5 is lifted further by the top of the adjustment platform 3. The heat dissipation effect of the edge area of ​​the substrate holder 5 is further reduced. During this process, the side wall of the middle step 3-2 comes into contact with the inner wall of the support 4, so that the heat in the center area of ​​the substrate holder 5 can be carried away not only by the cooling circuit inside the cooling platform 2, but also by the cooling circuit inside the side wall 1-1. This further reduces the temperature in the center area of ​​the substrate holder 5, and the temperature difference between the center area and the edge area of ​​the substrate holder 5 is reduced again. This is the third stage of heat dissipation.

[0057] During steps 2) and 3), it should be emphasized that the apparatus provided in this invention is typically used in a growth chamber. The position of the substrate 6 within the growth chamber usually needs to remain constant during the growth process to ensure the stability of the plasma distribution. Therefore, in steps 2) and 3), when the position of the substrate 6 is raised, the stationary stage 1 needs to move downwards, causing the entire apparatus to shift downwards, thereby offsetting the rise of the substrate 6 and maintaining a constant height of the substrate 6 within the growth chamber.

[0058] In addition, during the first, second, and third stages of heat dissipation, when the temperature of the central region of the substrate 6 is lower than that of the edge region, the cooling stage 2 is lowered. Specifically, during the second and third stages of heat dissipation, while the cooling stage 2 is lowered, the fixing stage 1 gradually moves upwards to keep the substrate 6 in its original position. That is, if the opposite situation occurs during the growth of the substrate 6—the temperature of the edge region being higher than that of the central region—the cooling stage 2 and the fixing stage 1 can reverse their operation at any time in steps 1), 2), and 3).

[0059] Example 1

[0060] In this embodiment, the substrate 6 is made of single-crystal silicon, and the diameter Ø0 of the substrate 6 is 110 mm and the thickness is 3 mm, and the structural component size is selected.

[0061] The bracket 4 is fixedly connected to the top of the fixed platform 1 by a 5 mm diameter threaded screw, that is, the upper edge step 4-1 is threadedly connected to the top of the fixed platform 1. The recess height H2 of the bracket 4 is 31 mm, the inner diameter Ø3 of the bracket 4 is 120 mm, the height H3 of the lower edge step 4-2 is 16 mm, the inner diameter Ø4 of the lower edge step 4-2 is 90 mm, and the lower edge step 4-2 can overlap to place the substrate holder 5.

[0062] The substrate holder 5 has a diameter Ø1 of 120 mm and a height H1 of 30 mm; the top groove 5-1 has a depth of 1 mm and a diameter Ø0 of 121 mm; the bottom groove 5-2 has a depth of 0.5 mm and a diameter Ø2 of 75 mm.

[0063] The adjustment platform 3 has the following dimensions: the upper step 3-1 has a diameter of Ø5 of 75 mm and a height of H5 of 31 mm; the middle step 3-2 has a diameter of Ø6 of 90 mm and a height of H6 of 16 mm; and the lower step 3-3 has a diameter of Ø7 of 150 mm and a height of H7 of 2 mm.

[0064] Initially, the straight-line distance H4 from the upper surface of the lower step 3-3 to the lower surface of the lower edge step 4-2 is 37 mm (hereinafter referred to as distance H4), and the straight-line distance between the upper surface of the upper step 3-1 and the lower surface of the substrate holder 5 is 6 mm. The upper step 3-1 does not contact the substrate holder 5, and the cooling circuit inside the sidewall 1-1 plays a dominant role in cooling. Initially, the temperature of the edge region of the substrate holder 5 is lower than that of the middle region. The initial position of the substrate 6 in the cavity is recorded to locate the 0 point of the substrate 6.

[0065] Subsequently, the growth chamber was evacuated to a vacuum level of 10. -2 Pa, hydrogen gas is introduced to start the microwave power supply. The sample growth process typically includes the following stages: heating stage, growth stage, annealing stage, and cooling stage.

[0066] Heating stage: Adjust the gas pressure and microwave power of the MPCVD (microwave plasma chemical vapor deposition) equipment to ensure plasma coverage of substrate 6. During this process, gradually raise the cooling stage 2. When the distance to H4 is 32 mm, the upper step 3-1 gradually approaches the middle region of the substrate support 5 (the straight-line distance between the upper surface of the upper step 3-1 and the lower surface of the substrate support 5 is 1 mm). The heat dissipation effect of the middle region of substrate 6 is gradually improved. At this time, the temperature difference ΔT between the middle region and the edge region of substrate 6 is ≤ 20 ℃ (obtained by subtracting the lowest temperature of the edge region of substrate 6 from the highest temperature of the middle region of substrate 6).

[0067] Growth stage: Continuously monitor the temperature difference ΔT, continue to raise the cooling stage 2, adjust the top of the stage 3 to push the substrate holder 5 upward and gradually move it away from the support 4, while lowering the fixing stage 1 to keep the substrate 6 near the 0 point. At this time, the temperature of the edge region of the substrate 6 increases as it moves away from the support 4 (i.e., away from the cooling circuit inside the fixing stage 1), with a temperature difference ΔT ≤ 10 ℃ and a distance of 25 mm from H4.

[0068] During the 210h growth period, the temperature in the middle region of substrate 6 increased, causing the temperature difference ΔT to gradually increase. The cooling stage 2 was raised and the fixing stage 1 was lowered to keep substrate 6 near the 0 site. At the end of the growth segment, the distance from H4 was 23 mm, and the temperature difference ΔT was maintained at ≤10℃.

[0069] Annealing section: After shutting off methane, increase power and gas pressure to raise the temperature to 1003 ℃ (maximum temperature) for annealing. At this point, the temperature difference ΔT changes by +15 ℃. Continue to raise the cooling stage 2 and lower the fixing stage 1 to keep the substrate 6 near the 0 point. The temperature of the edge region of the substrate 6 continues to rise, maintaining a temperature difference ΔT ≤ 10 ℃. At the end of annealing, the distance from H4 is 17 mm.

[0070] Cooling stage: After annealing, gradually and slowly reduce the power and gas pressure, monitor the temperature changes in the edge and middle areas of substrate 6, adjust the height of cooling stage 2 and fixed stage 1 to control the temperature difference to ≤10 ℃, repeat the cooling and adjusting of the height of cooling stage 2 and fixed stage 1 to avoid cracking caused by uneven cooling during the cooling process.

[0071] In this embodiment, the sidewall of the middle step 3-2 does not contact the sidewall of the lower edge step 4-2, so only the first and second stages of heat dissipation are actually used, and the third stage of heat dissipation is not used.

[0072] The test temperatures for each stage in this embodiment are shown in Table 2.

[0073] Table 2

[0074] Position on substrate 6 / mm Heating range / ℃ Growth stage start-up / ℃ At the end of the growth stage / ℃ Annealing section / ℃ Cooling section / ℃ -55 771 842 848 996 829 -45 770 844 847 995 827 -35 774 846 848 997 828 -25 778 845 850 998 829 -15 780 847 853 1002 832 -5 784 849 856 1001 831 0 788 850 855 1002 832 5 786 851 855 1003 834 15 782 848 853 1001 833 25 779 846 852 999 829 35 773 846 851 997 828 45 773 845 850 997 827 55 771 843 847 998 829 Temperature difference ΔT / ℃ 18 9 9 9 7 H4 height / mm 32 25 23 17 20

[0075] Example 2

[0076] In this embodiment, the substrate 6 is made of single-crystal diamond, and the diameter Ø0 of the substrate 6 is 50 mm and the thickness is 3 mm, which is the size of the structural component.

[0077] The bracket 4 is fixedly connected to the top of the fixed platform 1 by a 3 mm diameter threaded screw, that is, the upper edge step 4-1 is threadedly connected to the top of the fixed platform 1. The recess height H2 of the bracket 4 is 16 mm, the inner diameter Ø3 of the bracket 4 is 60 mm, the height H3 of the lower edge step 4-2 is 13 mm, the inner diameter Ø4 of the lower edge step 4-2 is 40 mm, and the lower edge step 4-2 can overlap to place the substrate holder 5.

[0078] The substrate holder 5 has a diameter Ø1 of 60 mm and a height H1 of 15 mm; the top groove 5-1 has a depth of 1 mm and a diameter Ø0 of 51 mm; the bottom groove 5-2 has a depth of 0.5 mm and a diameter Ø2 of 35 mm.

[0079] The adjustment platform 3 has the following dimensions: the upper step 3-1 has a diameter of Ø5 of 35 mm and a height of H5 of 20 mm; the middle step 3-2 has a diameter of Ø6 of 40 mm and a height of H6 of 15 mm; and the lower step 3-3 has a diameter of Ø7 of 90 mm and a height of H7 of 1 mm.

[0080] Initially, the straight-line distance H4 from the upper surface of the lower step 3-3 to the lower surface of the lower edge step 4-2 is 31 mm (hereinafter referred to as distance H4), and the straight-line distance between the upper surface of the upper step 3-1 and the lower surface of the substrate holder 5 is 8 mm. The upper step 3-1 does not contact the substrate holder 5, and the cooling circuit inside the sidewall 1-1 plays a dominant role in cooling. Initially, the temperature of the edge region of the substrate holder 5 is lower than that of the middle region. The initial position of the substrate 6 in the cavity is recorded to locate the 0 point of the substrate 6.

[0081] Subsequently, the growth chamber was evacuated to a vacuum level of 10. -2 Pa, hydrogen gas is introduced to start the microwave power supply. The sample growth process typically includes the following stages: heating stage, growth stage, annealing stage, and cooling stage.

[0082] Heating phase: Adjust the gas pressure and microwave power of the MPCVD (microwave plasma chemical vapor deposition) equipment to ensure that the plasma covers the substrate 6. During this process, the cooling stage 2 gradually moves upward. When the distance H4 is 24 mm (the straight-line distance between the upper surface of the upper step 3-1 and the lower surface of the substrate support 5 is 1 mm), the upper step 3-1 gradually contacts the middle area of ​​the substrate support 5. The heat dissipation effect of the middle area of ​​the substrate 6 is gradually improved. At this time, the temperature difference of the substrate 6 is within +30 ℃ (obtained by subtracting the lowest temperature of the edge area of ​​the substrate 6 from the highest temperature of the middle area of ​​the substrate 6).

[0083] Growth Stage: Continuously monitor the temperature difference ΔT. Continue raising the cooling stage 2, and adjust the top of the stage 3 to push the substrate holder 5 upwards and gradually move it away from the support 4. Simultaneously, lower the fixed stage 1 to keep the substrate 6 near the 0 point. At this time, the temperature of the edge region of the substrate 6 increases as it moves away from the support 4 (i.e., away from the cooling circuit inside the fixed stage 1), maintaining a temperature difference ΔT of +14 ℃ and a distance of 18 mm from H4. At this stage, the second-stage heat dissipation reaches its limit, and a third-stage heat dissipation is adopted. The cooling stage 2 is further raised so that the middle step 3-2 gradually contacts the lower edge step 4-2, improving heat dissipation in the middle region. The substrate holder 5 continues to move away from the side support 4, increasing the temperature of the edge region of the substrate 6. This dual effect reduces the temperature difference. During this process, lower the fixed stage 1 to keep the substrate 6 near the 0 point, maintaining a temperature difference ΔT ≤ 10 ℃ and a distance of 10 mm from H4.

[0084] Subsequently, after 110 hours of growth, the temperature of the edge region of substrate 6 gradually increased, and the temperature difference ΔT changed to -12 ℃ (the lowest temperature in the middle region minus the highest temperature in the edge region, i.e., the temperature in the middle region is 12 ℃ lower than that in the edge region). The cooling stage 2 was lowered, while the fixed stage 1 was raised to keep substrate 6 near the 0 site, maintaining a temperature difference ΔT ≤ 10 ℃, and a distance of 14 mm from H4.

[0085] During the growth period of 110h to 240h, the height of cooling platform 2 was finely adjusted according to the temperature difference ΔT. After 240h of growth, the distance from H4 was 16 mm.

[0086] Annealing section: After shutting off methane, increase power and gas pressure to raise the temperature to 982℃ for annealing. At this point, the temperature difference between the edge and center regions of the substrate will change to within +12℃, and H4 = 16mm. Continue to raise the cooling stage 2 and lower the fixing stage 1, keeping the substrate 6 near the 0 point. The temperature of the edge region of the substrate 6 continues to rise, and the temperature difference between the edge and center regions of the substrate 6 is maintained within +10℃. At the end of annealing, the distance H4 is 11 mm.

[0087] Cooling stage: Gradually and slowly reduce power and air pressure, monitor temperature changes in the edge and middle areas of substrate 6, adjust the height of cooling stage 2 and fixed stage 1 to control the temperature difference within 10℃, repeat the cooling and adjustment of cooling stage 2 and fixed stage 1 to avoid cracking caused by uneven cooling during the cooling process.

[0088] In this embodiment, the first-stage heat dissipation, the second-stage heat dissipation, and the third-stage heat dissipation are fully utilized.

[0089] The test temperatures for each stage in this embodiment are shown in Table 2.

[0090] Table 3

[0091] Location on substrate / mm Heating range / ℃ Heating range / ℃ Growth stage start-up / ℃ Growth time 110 hours / ℃ At the end of the growth stage / ℃ Annealing section / ℃ Cooling section / ℃ -25 740 834 847 861 853 973 635 -20 745 836 849 857 852 974 636 -15 752 838 850 855 848 977 639 -10 758 840 851 856 846 980 640 -5 760 843 852 854 849 982 643 0 762 846 854 856 850 981 643 5 755 843 853 853 848 981 644 10 750 840 850 854 845 980 644 15 743 838 849 855 850 978 641 20 740 834 848 858 851 975 638 25 736 833 846 860 854 974 636 Overall temperature difference ΔT / ℃ 26 13 8 -8 -9 9 9 H4 height / mm 24 18 10 14 16 11 12

[0092] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A device for in-situ regulating the temperature field of diamond growth, characterized in that, include: A liftable fixed platform, the fixed platform including a side wall and a cavity surrounded by the side wall, the cavity having a liftable cooling platform inside, and the interior of the side wall and the interior of the cooling platform being connected to an external cooling circuit respectively; The cavity is also equipped with an adjustment platform located above the cooling platform. The adjustment platform includes an upper step and a middle step located below the upper step. The top of the fixed platform is equipped with a bracket, the bottom of which is not closed. A substrate support is provided on the bracket to support the substrate, which is used for diamond deposition.

2. The device for in-situ adjustment of the diamond growth temperature field according to claim 1, characterized in that, The adjustment platform also includes a lower step located below the middle step, and the diameters of the lower step, middle step, and upper step decrease sequentially.

3. The device for in-situ adjustment of the diamond growth temperature field according to claim 1, characterized in that, The support includes an upper edge step located at the top of the support, which is connected to the top of the fixed platform.

4. The device for in-situ adjustment of the diamond growth temperature field according to claim 3, characterized in that, The support also includes a lower edge step located at the bottom of the support, the lower edge step extending in the opposite direction to the upper edge step, and the inner diameter of the lower edge step being not less than the outer diameter of the middle step.

5. The device for in-situ adjustment of the diamond growth temperature field according to claim 1, characterized in that, The substrate holder has a bottom groove at its bottom, the diameter of which is not less than the diameter of the upper step; and / or, the substrate holder has a top groove at its top, the top groove being used to support the substrate.

6. The device for in-situ adjustment of the temperature field for diamond growth according to claim 1, characterized in that, The substrate material is selected from any one of the following: silicon wafers, diamond single crystals or multi-crystal wafers, silicon carbide wafers, gallium nitride wafers, and other non-metallic wafers, or high-temperature resistant metals and alloys such as molybdenum wafers and tungsten wafers; and / or, the substrate holder material is selected from any one of the following: molybdenum, copper, stainless steel, tungsten, nickel, titanium, niobium, tantalum, and other metals or alloys.

7. The apparatus for in-situ adjustment of the diamond growth temperature field according to claim 5, characterized in that, The material of the support is selected from any one of molybdenum, copper, stainless steel, tungsten, nickel, titanium, niobium, tantalum or alloys, and preferably, the support is a solid structure.

8. A method for in-situ regulating the temperature field of diamond growth, characterized in that, The apparatus for in-situ adjustment of the diamond growth temperature field as described in any one of claims 1 to 7 comprises: Raise the cooling platform, and adjust the top of the platform to gradually contact the bottom of the substrate holder to form the first stage of heat dissipation; Optionally, the cooling stage is raised, and the top of the stage pushes the substrate holder upward and gradually away from the support, raising the relative position of the stage with respect to the fixed stage; at the same time, the fixed stage gradually moves downward, lowering the absolute position of the substrate holder, thereby keeping the substrate in place and forming a second stage of heat dissipation. Alternatively, the cooling platform can be raised so that the relative position of the adjusting platform with respect to the fixed platform is raised, and the side wall of the middle step contacts the inner wall of the support; at the same time, the fixed platform gradually moves downward so that the absolute position of the substrate holder is lowered, thereby keeping the substrate in place and forming a third stage of heat dissipation.

9. The method according to claim 8, characterized in that, During the first, second, and third stages of heat dissipation, when the temperature in the central region of the substrate is lower than that in the edge region, the cooling stage is lowered, causing the relative position of the adjusting stage to the fixed stage to decrease. During the second and third stages of heat dissipation, while the cooling stage is lowered, the fixed stage gradually moves upward, causing the absolute position of the substrate support to rise, thereby keeping the substrate in its original position.

10. The method according to claim 8, characterized in that, The height of the relative displacement limit between the substrate holder and the support is such that the lower surface of the substrate holder does not exceed the upper surface of the support.

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