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Hot cathode direct current plasma chemical vapor deposition equipment (DCCVD)

모델명 :
제품 견적문의

상품상세정보

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.

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.

 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;