Bias voltage sample table adopting microwave plasma deposition

Abstract

The utility model discloses a bias voltage sample table adopting microwave plasma deposition, and belongs to the technical field of diamond preparation. Comprising a microwave plasma chemical vapor deposition equipment reaction chamber, a water-cooling deposition table, a bias electrode lifting table, a quartz cylinder and a tungsten annular bias electrode, and a bias sample table is arranged at the bottom of the microwave plasma chemical vapor deposition equipment reaction chamber; and a quartz microwave window is arranged at the top of the reaction chamber of the microwave plasma chemical vapor deposition equipment. According to the utility model, the bias electrode for directly applying bias voltage to the plasma and the water-cooling deposition table are integrated, and the high and low positions of the bias electrode and the water-cooling deposition table can be independently adjusted, so that the most suitable real-time relative positions of the electrode, the sample table and the plasma can be easily found, and the stable, uniform and efficient bias voltage enhanced nucleation process is realized; and uniform nucleation and growth of the diamond on the deposition substrate are facilitated.

Description

Technical Field

[0001] This utility model relates to the field of diamond preparation technology, and in particular to a bias voltage sample stage using microwave plasma deposition. Background Technology

[0002] Diamond possesses excellent physical properties, such as extremely high hardness and elastic modulus, extremely high room temperature thermal conductivity, relatively wide bandgap and electromagnetic wave transmission range, excellent dielectric and insulating properties, excellent semiconductor properties, good chemical stability, and extremely high radiation resistance threshold, making it a much-needed new material in many traditional and high-tech fields. Microwave plasma chemical vapor deposition (MPCVD) technology offers advantages over other deposition methods, including high-quality deposited films, no electrode contamination, good controllability, and stable deposition parameters, making it the preferred method for depositing high-quality carbon-based thin films. MPCVD can be further divided into homoepitaxial and heteroepitaxial processes. Heteroepitaxial processes refer to the method of obtaining large-size epitaxial single diamond films by high-density epitaxial nucleation on non-diamond substrates and controlling the growth process to achieve grain merging and texture growth. Nucleation is the first step in heteroepitaxial diamond film preparation; improving nucleation density and uniformity is crucial. The most typical method to increase nucleation density is bias-enhanced nucleation (BEN), which involves applying a bias voltage to a heterogeneous substrate, causing certain particles in the plasma to accelerate and bombard the substrate, resulting in a series of interactions. Under the combined influence of carbon dissolution-precipitation and the substrate's template effect, diamond achieves a self-assembly epitaxial nucleation process. The uniformity of nucleation has a significant impact on the orientation, stress level, and crystal quality of the subsequently grown diamond.

[0003] The commonly reported method for applying bias voltage is to apply a DC bias voltage to the deposition substrate. This involves connecting the positive terminal of the DC power supply to the CVD equipment cavity and then grounding it, while the deposition stage where the heterostructure substrate is placed is connected to the negative terminal of the power supply, thus achieving a certain negative bias voltage on the deposition substrate (Patent Applications 202311600878.4, 201621057920.8, 202310318067.9, 202122932580.6). Conventional diamond deposition stages require a cooling water connection, and applying bias voltage to the deposition stage necessitates consideration of the cooling water circuit insulation. This results in a complex bias voltage device and a relatively low voltage. Furthermore, because the bias current varies only slightly with the bias voltage, the bias current level is low, leading to poor bias efficiency. This results in a concentrated and uneven distribution of primary diamond nuclei obtained from heteroepitaxial growth, i.e., poor nucleation uniformity, which is detrimental to the preparation of high-quality diamond.

[0004] Therefore, there is an urgent need to provide a bias voltage sample stage using microwave plasma deposition to solve the above problems. Utility Model Content

[0005] The technical problem to be solved by this utility model is to overcome the shortcomings of the prior art and provide a bias voltage sample stage using microwave plasma deposition.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A bias voltage sample stage using microwave plasma deposition is provided, comprising a microwave plasma chemical vapor deposition (PCVDC) equipment reaction chamber, a water-cooled deposition stage, a bias electrode lifting stage, a quartz cylinder, and a tungsten annular bias electrode. The bias sample stage is located at the bottom of the PCVDC reaction chamber, and a quartz microwave window is located at the top of the PCVDC reaction chamber. The water-cooled deposition stage is located at the center inside the PCVDC reaction chamber and is made of metal. A diamond deposition substrate is connected to the top of the water-cooled deposition stage, and plasma is disposed on the top of the diamond deposition substrate.

[0007] Through the above technical solution, this device applies a bias voltage to the plasma via a ring electrode, avoiding the problems of poor insulation, complex device, and low maximum allowable bias voltage caused by applying a bias voltage to a water-cooled deposition stage in traditional methods.

[0008] The present invention is further configured such that: the bottom two sides of the water-cooled deposition stage are connected to the bias electrode lifting stage through vacuum compression bellows A, the bottom of the water-cooled deposition stage is connected to a lifting motor B, and tungsten annular bias electrodes are provided on the outer two sides of the water-cooled deposition stage.

[0009] Through the above technical solution, this device is designed with highly independent and adjustable bias electrodes and deposition stages, which can adjust the relative positions of the bias electrodes, deposition stages and plasma in real time and with precision, which helps to achieve a stable, uniform and efficient diamond bias-enhanced nucleation process.

[0010] The present invention is further configured such that: the tungsten annular bias electrode is placed on the top of the quartz cylinder, and the quartz cylinder is placed on the top of the bias electrode lifting platform.

[0011] The present invention is further configured such that: the two sides of the bias electrode lifting platform are connected to the reaction chamber of the microwave plasma chemical vapor deposition equipment through vacuum compression bellows B.

[0012] Through the above technical solution, the device is designed with a height-adjustable bias electrode, which can be lowered to move away from the plasma after the diamond bias-enhanced nucleation process is completed. This avoids the plasma from eroding the bias electrode during the subsequent diamond growth process and also avoids the contamination of the diamond film by the metal atoms in the bias electrode.

[0013] The present invention is further configured such that: a lifting motor A is connected to the bottom of one side of the bias electrode lifting platform, and one of the tungsten annular bias electrodes is connected to a vacuum-sealed connector through a high-temperature resistant wire.

[0014] The present invention is further configured such that: the high-temperature resistant wire and the vacuum-sealed connector are connected to the outside of the reaction chamber of the microwave plasma chemical vapor deposition equipment, and the high-temperature resistant wire is further connected to a DC bias power supply, wherein the high-temperature resistant wire is connected to the positive terminal of the DC bias power supply.

[0015] Through the above technical solution, this device is designed with a highly adjustable bias electrode, which can complete the two steps of bias-enhanced nucleation and diamond growth in the same production process. This avoids the need for shutdown and startup, switching the reactor on and off, unnecessary cooling and heating processes between these two steps, and the negative impact on diamond nucleation and deposition.

[0016] The beneficial effects of this utility model are as follows:

[0017] 1. This invention applies a positive bias voltage directly to the plasma via electrodes, instead of applying a negative bias voltage to the sample stage. Therefore, the sample stage can always remain grounded, thus avoiding the problem of electrically insulating the sample stage (especially the water-cooled sample stage) required to apply a negative bias voltage.

[0018] 2. This utility model is designed so that the height of the bias electrode and the deposition sample stage can be independently adjusted in real time. Therefore, the relative positions of the electrode, sample stage and plasma can be adjusted. This allows the two steps of bias-enhanced nucleation and diamond growth to be completed in the same production process. This avoids the need to stop and start the machine, switch the reactor on and off, and the unnecessary cooling and heating processes between these two steps, as well as the negative impact on diamond nucleation and deposition.

[0019] 3. This invention features an adjustable bias electrode height, allowing the bias electrode to be raised to a high position during the bias nucleation step until it comes into contact with the plasma. This effectively reduces the contact resistance between the two and improves the bias efficiency. After the bias nucleation step, the bias electrode can be lowered to its lowest position, keeping it away from the plasma. This completely eliminates the etching effect of the plasma on the bias electrode in subsequent diamond growth steps and the resulting contamination of the diamond deposition process.

[0020] 4. This invention, through independent, precise, and real-time adjustment of the height of the electrode and the sample stage, facilitates finding the most suitable real-time relative position of the electrode, the sample stage, and the plasma, thereby achieving a stable, uniform, and efficient bias-enhanced nucleation process.

[0021] 5. This invention directly applies a bias voltage to the plasma through electrodes, which can generate a stable and uniform electric field between the plasma and the sample stage. Since plasma has excellent conductivity, it is beneficial for the uniform nucleation and growth of diamond on the deposition substrate. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of this utility model;

[0023] Figure 2 This is a structural diagram showing the relative positions of the water-cooled deposition stage, the bias electrode, and the plasma in the bias-enhanced nucleation process of diamond growth according to this utility model.

[0024] Figure 3 This is a structural diagram showing the relative positions of the water-cooled deposition stage, the bias electrode, and the plasma in the bias-enhanced nucleation diamond growth of this invention.

[0025] In the figure: 1. Reaction chamber of microwave plasma chemical vapor deposition equipment; 2. Quartz microwave window; 3. Plasma; 4. Water-cooled deposition stage; 5. Bias electrode lifting stage; 6. Vacuum compression bellows A; 7. Vacuum compression bellows B; 8. Lifting motor A; 9. Lifting motor B; 10. Quartz cylinder; 11. Tungsten annular bias electrode; 12. High-temperature resistant wire; 13. Vacuum-sealed connector; 14. DC bias power supply; 15. Diamond deposition substrate. Detailed Implementation

[0026] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the scope of protection of the present invention.

[0027] Please see Figures 1-3 A bias voltage sample stage using microwave plasma deposition includes a microwave plasma chemical vapor deposition equipment reaction chamber 1, a water-cooled deposition stage 4, a bias electrode lifting stage 5, a quartz cylinder 10, and a tungsten annular bias electrode 11. The bias electrode lifting stage 5 is connected to the microwave plasma chemical vapor deposition equipment reaction chamber 1 on both sides through vacuum compression bellows B7. This satisfies the requirement for independent lifting of the bias electrode lifting stage 5 while isolating the reaction chamber and maintaining its airtightness.

[0028] The bottom of the reaction chamber 1 of the microwave plasma chemical vapor deposition equipment is equipped with a bias sample stage. A lifting motor A8 is connected to one side of the bottom of the bias electrode lifting stage 5 to control and adjust the height of the bias electrode lifting stage 5. One of the tungsten ring bias electrodes 11 is connected to a vacuum-sealed connector 13 through a high-temperature resistant wire 12.

[0029] The high-temperature resistant wire 12 and the vacuum-sealed connector 13 are connected to the outside of the reaction chamber 1 of the microwave plasma chemical vapor deposition equipment. The high-temperature resistant wire 12 is further connected to a DC bias power supply 14. The high-temperature resistant wire 12 is connected to the positive terminal of the DC bias power supply 14, thereby applying a positive voltage to the tungsten ring bias electrode 11. The reaction chamber, the water-cooled deposition stage 4, the bias electrode lifting stage 5, etc. are grounded to maintain zero potential.

[0030] The microwave plasma chemical vapor deposition (IPV) equipment has a quartz microwave window 2 at the top of the reaction chamber 1. During operation, microwave energy enters the reaction chamber through the quartz microwave window 2 and forms plasma 3 above the diamond deposition substrate 15, thus achieving diamond deposition. The water-cooled deposition stage 4 is located at the center of the reaction chamber 1. The bottom sides of the water-cooled deposition stage 4 are connected to the bias electrode lifting stage 5 through vacuum compression bellows A6. This satisfies the requirement for independent lifting of the water-cooled deposition stage 4 and isolates the reaction chamber, maintaining its airtightness. The bottom of the water-cooled deposition stage 4 is connected to a lifting motor B9 to control and adjust its height. Tungsten annular bias electrodes 11 are installed on both sides of the water-cooled deposition stage 4.

[0031] A tungsten annular bias electrode 11 is placed on top of a quartz cylinder 10. The tungsten annular bias electrode 11 is arranged around the outside of the water-cooled deposition stage 4 and placed on a quartz cylindrical support to maintain electrical insulation from other parts of the bias device. The quartz cylinder 10 is placed on top of the bias electrode lifting platform 5. The water-cooled deposition stage 4 is made of metal, and the hollow part can be circulated with cooling water to cool the deposition substrate. A diamond deposition substrate 15 is connected to the top of the water-cooled deposition stage 4, and a plasma 3 is provided on the top of the diamond deposition substrate 15.

[0032] When this utility model is used, (1) before the bias-enhanced nucleation process begins, the microwave source is turned on to form plasma 3, and the bias electrode lifting platform 5 is raised so that the bias electrode approaches and eventually contacts the plasma 3. At the same time, the height of the water-cooled deposition platform 4 can be adjusted so that the state of plasma 3 above the deposition substrate is optimized, including the maximum area, the most uniform distribution, and the most stable operation. During the bias-enhanced nucleation process, a positive bias voltage is applied to the bias electrode by the DC bias power supply 14. Since the bias electrode and plasma 3 are in direct contact, the potential of plasma 3 tends to be close to the bias electrode. Thus, the potential difference between plasma 3 and the grounded (zero potential) deposition substrate tends to be close to the positive bias voltage on the bias electrode, thereby triggering the bias nucleation process. During the bias-enhanced nucleation process, the height of the bias electrode and the water-cooled deposition platform 4 can be dynamically adjusted to achieve the optimal bias nucleation effect.

[0033] (2) After the bias-enhanced nucleation process is completed, the plasma is kept constant, the DC bias power supply 14 is turned off, and the bias electrode lifting platform 5 is lowered to the lowest level so that the bias electrode is far away from the plasma 3. At the same time, the height of the water-cooled deposition platform 4 can be adjusted so that the state of the plasma 3 above the deposition substrate is optimized, including the maximum area, the most uniform distribution, and the most stable operation. The diamond growth process begins. During this process, the height of the water-cooled deposition platform 4 can be dynamically adjusted to achieve the best diamond growth effect.

[0034] The above description is merely an embodiment of this utility model and does not limit the patent scope of this utility model. Any equivalent structural or procedural transformations made based on the description and drawings of this utility model, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this utility model.

Claims

1. A bias voltage sample stage using microwave plasma deposition, comprising a microwave plasma chemical vapor deposition equipment reaction chamber (1), a water-cooled deposition stage (4), a bias electrode lifting stage (5), a quartz cylinder (10), and a tungsten ring bias electrode (11), characterized in that: The microwave plasma chemical vapor deposition equipment reaction chamber (1) is provided with a bias sample stage at the bottom and a quartz microwave window (2) at the top. The water-cooled deposition stage (4) is located at the center inside the microwave plasma chemical vapor deposition equipment reaction chamber (1) and is made of metal. The top of the water-cooled deposition stage (4) is connected to a diamond deposition substrate (15) and plasma (3) is provided on the top of the diamond deposition substrate (15).

2. The bias voltage sample stage using microwave plasma deposition according to claim 1, characterized in that: The bottom sides of the water-cooled deposition stage (4) are connected to the bias electrode lifting stage (5) through vacuum compression bellows A (6). The bottom of the water-cooled deposition stage (4) is connected to a lifting motor B (9). Tungsten annular bias electrodes (11) are provided on the outer sides of the water-cooled deposition stage (4).

3. The bias voltage sample stage using microwave plasma deposition according to claim 2, characterized in that: The tungsten annular bias electrode (11) is placed on top of the quartz cylinder (10), which is placed on top of the bias electrode lifting platform (5).

4. A bias voltage sample stage for microwave plasma deposition according to claim 1, characterized in that: The bias electrode lifting platform (5) is connected to the reaction chamber (1) of the microwave plasma chemical vapor deposition equipment through vacuum compression bellows B (7) on both sides.

5. A bias voltage sample stage for microwave plasma deposition according to claim 2, characterized in that: The bottom of one side of the bias electrode lifting platform (5) is connected to a lifting motor A (8), and one of the tungsten annular bias electrodes (11) is connected to a vacuum-sealed connector (13) via a high-temperature resistant wire (12).

6. A bias voltage sample stage for microwave plasma deposition according to claim 5, characterized in that: The high-temperature resistant wire (12) and vacuum-sealed connector (13) are connected to the outside of the reaction chamber (1) of the microwave plasma chemical vapor deposition equipment, and the high-temperature resistant wire (12) is further connected to a DC bias power supply (14), and the high-temperature resistant wire (12) is connected to the positive terminal of the DC bias power supply (14).

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