Microwave plasma CVD (chemical vapor deposition) monocrystal diamond preparation device capable of improving stability and monocrystal diamond preparation method

Abstract

The invention relates to the technical field of diamond substrate preparation, in particular to a microwave plasma CVD (chemical vapor deposition) monocrystal diamond preparation device capable of improving stability and a monocrystal diamond preparation method. The device comprises microwave generators, a waveguide is arranged below the microwave generators and connected with an antenna, and a microwave medium window is formed below the antenna; and a molybdenum support is arranged below the microwave medium window, a monocrystal diamond seed crystal is arranged above the molybdenum support, and the antenna, the microwave medium window, the molybdenum support and the monocrystal diamond seed crystal are arranged in the cavity. According to the device and the method, power supply uninterrupted production can be ensured, and if a certain microwave generator is abnormal, a power supply system can automatically conduct compensation or start other generators, so that the continuous production is ensured.

Description

technical field [0001] The invention relates to the technical field of diamond substrate preparation, in particular to a device for preparing single crystal diamond by microwave plasma CVD with improved stability and a method for preparing single crystal diamond. Background technique [0002] Microwave plasma CVD (Chemical Vapor Deposition) equipment can synthesize gem-grade single crystal diamond, but the power supply of ordinary microwave plasma 250,000 plasma CVD deposition equipment to synthesize single crystal diamond is usually 6-30 kilowatts per unit, microwave equipment is fast Heating, the plasma center temperature is high, the substrate temperature is between 800-1300, and the substrate stage is cooled by water. If there is an abnormal situation, the output power will suddenly stop, causing the wafer to cool down rapidly to about 20°C, resulting in huge The thermal stress of the diamond crystal causes the internal lattice of the diamond crystal to break, and the ma...

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Problems solved by technology

[0002] Microwave plasma CVD (Chemical Vapor Deposition) equipment can synthesize gem-grade single crystal diamond, but the power supply of ordinary microwave plasma 250,000 daughter CVD deposition equipment to synthesize single crystal diamond is usually 6-30 kilowatts per unit, and microwave equipment is fast Heating, the plasma center temperature is high, the substrate temperature is between 800-1300, and the substrate stage is cooled by water. If there is an abnormal situation, the output power will suddenly stop, causing the wafer to cool down rapidly to about 20°C, resulting in huge The thermal stress of the diamond crystal causes the internal lattice of the diamond crystal to break and the material to be scrapped

On the other hand, to achieve large-area growth of single crystal diamond, a high-power microwave power supply is required. Existing microwave (or direct current, hot wire) plasma chemical vapor deposition devices use high-power microwave power supplies, which are extremely costly. Power supply costs, microwave generators, and maintenance costs are extremely high. The cost of a single 6kw power supply is 450,000 for a 15kw power supply, and 900,000 for a 30kw unit. A single microwave generator: 30,000 for a 6kw magnetron, 15 A kilowatt is 80,000, 30 kilowatts is 150,000, and it is a consumable, which needs to be replaced in 1-2 years, resulting in high production costs and energy consumption, which hinders its large-scale application

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