6KW MPCVD Machine

Equipment composition and main characteristics:

1. Microwave power source

The system adopts a 6kW/2450MHz switch type microwave power source. Its microwave power is continuously adjustable from 0.5 to 6kW; Stability better than ± 1%; Ripple degree is better than 2%, with good control performance; PLC provides convenient control; Adopting advanced magnetron filament voltage reduction tracking technology and high-precision magnetic field feedback adjustment and stability technology; We have adopted a comprehensive line safety locking control system, which ensures a long working life, excellent electrical performance, safety and reliability, and simple and convenient operation.

2. Waveguide transmission unit

The system adopts an excellent microwave transmission system consisting of a high-performance microwave circulator, a three pin mixer, a water load with reflected wave sampling, and a connected waveguide segment waveguide. It ensures good isolation of the reflected wave from the magnetron, ensuring its stable operation. It can also conveniently adjust the optimal match when the plasma load changes, achieving the optimal transmission of microwave power. Through sampling of the reflected wave, the reflected power and real-time working status are displayed digitally.

3. Mode Transformation and Downinjection Microwave Coupling Cavity

This is a new generation of relatively mature microwave plasma coupling cavities, which are composed of cylindrical cavities operating in TM mode, gate button coaxial waveguide couplers with adjustable coaxial coupling probes, and plate quartz windows. By adjusting the waveguide short-circuit piston and coaxial coupling probe, microwave power can be efficiently coupled to the plasma discharge cavity over a wide operating range, generating high-density, high ionization degree, and large area uniform and stable microwave discharge. It adopts a double-layer water-cooled cavity wall to ensure stable operation.

4. Multi port plasma discharge cavity

This system adopts a large volume discharge chamber with a double-layer water-cooled structure welded from stainless steel, and the upper end is connected to the microwave reaction chamber, which is the continuation part of the cylindrical cavity. It also has the following functional ports:

1) A rotating door type feeding and discharging window is set up in front of the cavity, which can facilitate the discharge of substrate samples of no less than 50mm, and is equipped with a mesh microwave shielding window to clearly observe the discharge operation in the cavity during operation. Infrared temperature measurement is used for substrate temperature measurement at 300-1400 ℃

2) A specially designed inflation flange is used to provide the main mixing and inflation pipelines, as well as the inflation ring near the substrate, as an auxiliary inflation pipeline to form a double-layer gas feeding system.

The above design makes the water-cooled discharge chamber of this port have a large volume and complete functions, especially suitable for the needs of small-scale plasma processing.

5. Sample holder adjustment

This device can electrically continuously adjust the cavity plate and sample substrate stage respectively to achieve the optimal state of the plasma discharge area, which is simple, reliable, and easy to control. It can meet the requirements of various plasma processing processes.

6. Vacuum acquisition and measurement

The system uses a vacuum pump with a pumping speed of 8L/s as the pumping system, with an ultimate vacuum better than 6×10-1Pa. The system is equipped with medium to low pressure measurement gauges from the atmosphere to 10-1Pa and pressure resistance vacuum gauges from 100Pa to 100kPa. The measuring instruments are placed in the cabinet for easy control and reading.

Static sealing adopts silicone rubber and metal sealing; The dynamic seal adopts a metal corrugated pipe structure. The working pressure control is completed using high-precision valves and controllers, with stable air pressure control and convenient adjustment.

7. Multi channel gas mass flow control (MFC)

To ensure the process requirements of MPCVD, the system adopts a 4-way gas mass flow control system supply and control system (MFC) composed of H2 (1SLM), CH4 (100SCCM), O2 (50SCCM), and N2 (50SCCM). The system adopts a reliable 1/4 ‘VCR interface built-in in the equipment cabinet, which is short, compact, and easy to control and adjust.

8. The control system and cabinet

System adopt a compact and concise main structure, as well as independent control units. Adopting PLC and touch screen multi parameter control, the entire equipment has a beautiful appearance and easy and reliable operation. The main control cabinet is equipped with automatic protection for overcurrent, overheating, water interruption, as well as power and fault indications.Microwave leakage is superior to national standards.

Overall technical parameters of the equipment

1) Microwave source and system

Working frequency: 2450 ± 50MHz

Output power: 0.5~6kW continuously adjustable

Power stability: better than ± 1% (at rated power level)

Ripple degree: better than ± 2%

Control method: PLC control, touch screen operation

Output waveguide interface: BJ-26, 22 with FD-26, 22 standard flange

Input power supply: 380VAC/50Hz, three-phase four wire, separate ground wire, 8kW

Cooling water flow rate: 6L/min

System standing wave coefficient: VSWR ≤ 1.5

Microwave leakage: ≤ 2mW/cm2 (better than the national standard GB10436-89)

2) Microwave vacuum discharge cavity

Size and working mode: Φ 200 x 300 (H) TM mode

3) Vacuum acquisition: 8L/s vacuum pump

The ultimate vacuum degree is better than 6×10-1Pa

4) Gas mass flow rate: 4-way MFC (gas type and range can be determined by the user) H2 (1SLM), CH4 (100SCCM),O2 (50SCCM), N2 (50SCCM)

5) Sample stage device: Sample stage diameter Φ 60 mm, water-cooled structure;

Electric lifting adjustment distance: 0-80 mm

6) Substrate temperature measurement: Infrared temperature measurement range 300~1400 ℃ (monochromatic)

7) Total power supply: 380VAC ± 5%/50Hz, three-phase four wire, separate ground wire, 10kW

8) Total cooling water: 15L/min, clean soft water, inlet water temperature 20 ℃± 5 ℃;

9) External dimensions:~1.85 (L) x 0.9 (W) x 1.85 (H) m

10) Working technical parameters:

(1) The plasma discharge area of the system is not less than the diameter Φ 50mm; Stable discharge without deviation;

(2) Working temperature: 600~1200 ℃ (infrared temperature measurement);

(3) Working pressure: 1kPa~25kPa;

(4) Realize long-term (>24 hours) continuous and stable operation under set output power, gas flow rate, and pressure conditions.

Equipment composition and configuration

• Configuration List

• Spare parts list

Note: The entire equipment is guaranteed for one year (with the magnetron tube guaranteed by the supplier).

3、 Equipment acceptance standards:

1). Limit pressure: The limit pressure measured by an external vacuum gauge should be less than 1.0 x 10-2Torr (within 20 minutes of continuous pumping by the vacuum pump);

2). Vacuum leakage rate: The leakage rate of the vacuum chamber should be less than 100mtorr/h (holding pressure for more than 10 hours)

3). MW radiation: Microwave radiation should be less than 2 mW/cm2, measured by a microwave measuring instrument (tested at 5.0 kW)

4). Leakage: Confirm that the water pipe is not leaking

5). Safety interlocking: Confirm that each interlocking action is correct

6). System testing: System startup and operation function testing

7). Polycrystalline diamond growth: Polycrystalline diamond growth was tested on 2-inch Si wafers for more than 24 hours, and the diamond distribution on the sample surface was uniform, without nitrogen vacancy related impurity peaks. The grown Si wafers were provided by the manufacturer.

8). The equipment operates continuously for 72 hours to produce diamond single crystals or polycrystals, with a growth rate of 2 micrometers per hour.