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TN
Hot cathode direct current plasma chemical vapor deposition equipment (DCCVD) is developed on the basis of conventional cold cathode glow discharge, and is mainly used for the deposition and growth of diamond single crystal or polycrystalline film.
1. The composition area and basic characteristics of hot cathode glow discharge
The glow discharge of the hot cathode direct current plasma chemical vapor deposition equipment can be divided into four areas along the axis of the cathode to the anode: cathode glow layer, Faraday dark zone, positive column glow plasma ball, and anode glow layer. Among them, the cathode glow layer is a thin light-emitting layer close to the cathode, where the huge wave discharge occurs, which plays an important role in the glow discharge process; the Faraday dark zone is the transition zone between the cathode zone and the positive column zone. The electrons collide in the cathode region and lose energy, and the slow electrons are not enough to cause ionization and excitation, so they present a dark area that does not emit light; the glow plasma ball in the positive column area is at the most obvious position of the glow discharge, and its width is about the cathode The anode spacing is about 4/5, and the length changes with the change of the anode and cathode spacing; compared to the bright positive column area, the anode glow layer emits slightly darker light.
Hot cathode, high gas pressure and high current density are the basic characteristics of hot cathode glow discharge which are different from conventional cold cathode glow discharge. During discharge, there is a distribution of glow intensity, color, and brightness between the electrodes, which are divided into four obvious areas. The glow discharge covers the entire cathode surface, and the discharge voltage increases with the increase of the discharge current; the cathode electron emission is combined by the thermal emission and the γ process, and the degree of bias between the two is mainly determined by the cathode temperature; the cathode drop zone is to maintain the glow The indispensable part of the light discharge, the thickness of this area is very thin, there is a high potential drop, so the field strength in this area is very high, and generate a huge wave discharge. The current density of hot cathode glow discharge is much greater than that of cold cathode glow discharge.
2. DCCVD technical parameters of hot cathode DC plasma chemical vapor deposition equipment:
Deposition chamber | Stainless steel water-cooled interlayer | Design the appropriate cavity size according to the electrode size to ensure that there is no discharge between the cavity wall and the electrode |
Open cavity way | Lift to open the cavity or open the door in front, convenient for lofting and cleaning | |
Observation window | Set up multiple observation windows to ensure that the cathode, anode and deposition table can be observed | |
Vacuum system | Vacuum pump | Vacuum is pumped by mechanical pump, no need to configure molecular pump |
Ultimate vacuum | 0.1~1Pa | |
Pump down time | 5~15min | |
Vent setting | Ensure uniformity of pumping | |
Air pressure adjustment range | 0.1Pa~30KPa | |
Release valve | Can be restored to the atmosphere | |
Vacuum gauge | High-precision vacuum gauge accurately measures the pressure value of the cavity | |
Gas distribution system | Air source configuration | 5 gas sources of hydrogen, methane, nitrogen, argon, and oxygen, with an additional one reserved for backup |
Gas flow control | The volume flow is controlled by MFC, and a flow meter with a suitable range is selected according to the size of the cavity. Different flow sizes will affect the pressure rise time. In general, the flow rate of hydrogen: methane: nitrogen: argon: oxygen is 40:1:1:40:1 | |
Air intake setting | Reasonable air inlet setting to ensure air inlet uniformity | |
Water cooling system | Water cooler power | The cooling power and head of the water chiller should match the heat generation of the equipment and the cooling water flow, and the temperature should be adjustable, generally set at about 20°C |
Valve | The deposition chamber, cathode, and anode all need to be cooled, and a water separator needs to be installed, and manual valves are set at the inlet and outlet of each branch on the water separator. | |
Operating temperature | The anode working temperature is 600-1100℃, the cathode working temperature is 700-1100℃ | |
Power | Operating Voltage | 600~1200V, adjustable output voltage |
Working current | 6~15A | |
Control System | 1) Gas flow control; 2) Electrode lifting control, real-time display of cathode and anode distance, control accuracy 1mm; 3) Monitoring and display of cathode, anode and substrate temperature; 4) Some functions can be adjusted manually, such as air pressure; 5) Fault alarm to prevent misoperation; | |
Electrode | 1) The anode diameter is 60mm, and the material is copper 2) The diameter of the cathode is 80~100mm, and the material is molybdenum. After long-term use, carbon is easy to deposit on the surface of the cathode and the discharge is unstable. Therefore, it needs to be designed as a replaceable structure; 3) The distance between the cathode and anode is adjustable, the range is 10~60mm, the distance is displayed in real time, and the adjustment accuracy is 1mm; 4) The edges of the cathode and anode can be rounded to prevent edge discharge; 5) The anode can be negatively biased, and the bias voltage range is 0~400V; 6) The edge of the electrode is insulated to prevent edge discharge; | |
Hot cathode direct current plasma chemical vapor deposition equipment (DCCVD) is developed on the basis of conventional cold cathode glow discharge, and is mainly used for the deposition and growth of diamond single crystal or polycrystalline film.
1. The composition area and basic characteristics of hot cathode glow discharge
The glow discharge of the hot cathode direct current plasma chemical vapor deposition equipment can be divided into four areas along the axis of the cathode to the anode: cathode glow layer, Faraday dark zone, positive column glow plasma ball, and anode glow layer. Among them, the cathode glow layer is a thin light-emitting layer close to the cathode, where the huge wave discharge occurs, which plays an important role in the glow discharge process; the Faraday dark zone is the transition zone between the cathode zone and the positive column zone. The electrons collide in the cathode region and lose energy, and the slow electrons are not enough to cause ionization and excitation, so they present a dark area that does not emit light; the glow plasma ball in the positive column area is at the most obvious position of the glow discharge, and its width is about the cathode The anode spacing is about 4/5, and the length changes with the change of the anode and cathode spacing; compared to the bright positive column area, the anode glow layer emits slightly darker light.
Hot cathode, high gas pressure and high current density are the basic characteristics of hot cathode glow discharge which are different from conventional cold cathode glow discharge. During discharge, there is a distribution of glow intensity, color, and brightness between the electrodes, which are divided into four obvious areas. The glow discharge covers the entire cathode surface, and the discharge voltage increases with the increase of the discharge current; the cathode electron emission is combined by the thermal emission and the γ process, and the degree of bias between the two is mainly determined by the cathode temperature; the cathode drop zone is to maintain the glow The indispensable part of the light discharge, the thickness of this area is very thin, there is a high potential drop, so the field strength in this area is very high, and generate a huge wave discharge. The current density of hot cathode glow discharge is much greater than that of cold cathode glow discharge.
2. DCCVD technical parameters of hot cathode DC plasma chemical vapor deposition equipment:
Deposition chamber | Stainless steel water-cooled interlayer | Design the appropriate cavity size according to the electrode size to ensure that there is no discharge between the cavity wall and the electrode |
Open cavity way | Lift to open the cavity or open the door in front, convenient for lofting and cleaning | |
Observation window | Set up multiple observation windows to ensure that the cathode, anode and deposition table can be observed | |
Vacuum system | Vacuum pump | Vacuum is pumped by mechanical pump, no need to configure molecular pump |
Ultimate vacuum | 0.1~1Pa | |
Pump down time | 5~15min | |
Vent setting | Ensure uniformity of pumping | |
Air pressure adjustment range | 0.1Pa~30KPa | |
Release valve | Can be restored to the atmosphere | |
Vacuum gauge | High-precision vacuum gauge accurately measures the pressure value of the cavity | |
Gas distribution system | Air source configuration | 5 gas sources of hydrogen, methane, nitrogen, argon, and oxygen, with an additional one reserved for backup |
Gas flow control | The volume flow is controlled by MFC, and a flow meter with a suitable range is selected according to the size of the cavity. Different flow sizes will affect the pressure rise time. In general, the flow rate of hydrogen: methane: nitrogen: argon: oxygen is 40:1:1:40:1 | |
Air intake setting | Reasonable air inlet setting to ensure air inlet uniformity | |
Water cooling system | Water cooler power | The cooling power and head of the water chiller should match the heat generation of the equipment and the cooling water flow, and the temperature should be adjustable, generally set at about 20°C |
Valve | The deposition chamber, cathode, and anode all need to be cooled, and a water separator needs to be installed, and manual valves are set at the inlet and outlet of each branch on the water separator. | |
Operating temperature | The anode working temperature is 600-1100℃, the cathode working temperature is 700-1100℃ | |
Power | Operating Voltage | 600~1200V, adjustable output voltage |
Working current | 6~15A | |
Control System | 1) Gas flow control; 2) Electrode lifting control, real-time display of cathode and anode distance, control accuracy 1mm; 3) Monitoring and display of cathode, anode and substrate temperature; 4) Some functions can be adjusted manually, such as air pressure; 5) Fault alarm to prevent misoperation; | |
Electrode | 1) The anode diameter is 60mm, and the material is copper 2) The diameter of the cathode is 80~100mm, and the material is molybdenum. After long-term use, carbon is easy to deposit on the surface of the cathode and the discharge is unstable. Therefore, it needs to be designed as a replaceable structure; 3) The distance between the cathode and anode is adjustable, the range is 10~60mm, the distance is displayed in real time, and the adjustment accuracy is 1mm; 4) The edges of the cathode and anode can be rounded to prevent edge discharge; 5) The anode can be negatively biased, and the bias voltage range is 0~400V; 6) The edge of the electrode is insulated to prevent edge discharge; | |
