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DIY RF Coupling Plasma

Atoms consist of a positively charged nucleus surrounded by a cloud of negatively charged electrons. Sometimes atoms can gain or lose electrons, which leads to them acquiring a net positive or negative charge. An atom with a net charge is known as an ion. Plasma is a cloud of ions, and these can have a number of uses in the semiconducting processing industry. A plasma can be produced inside an Argon-filled vacuum chamber by using a power supply that generates radio frequency (RF) radiation.

Things You'll Need

RF vacuum chamber with Argon mass flow controller
Rotary pump
Turbo pump
RF power supply
RF matching network
2 RF cables

Instructions

- 1
  Switch on the rotary pump and wait for the pressure to get to 10^-3 millibar. Switch on the turbo pump, and wait for it to ramp up. Wait until a pressure of approximately 10^-6 millibar is reached.
- 2
  Connect an RF cable between the RF matching unit and RF power supply. Connect another cable between the RF matching unit, and the RF vacuum chamber electrode socket.
- 3
  Partially close the valve to the turbo pump. Switch on the Argon mass flow controller, and set a pressure of 15 millibar. Switch on the RF power supply and matching unit. Set a forward power of 50 Watts. The matching unit is heard as it tries to minimize the reflected RF power. When the reflected power is less than 1 percent of the forward power, increase the forward power to approximately 150 Watts. The plasma within the chamber should light, and be visible though the chamber view-port. Slowly decrease the forward power back to 50 Watts. The RF couple plasma is created.

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