1.Beneficial for sputtering and plating insulation film. The rapid change in electrode polarity can be used to directly sputter insulating targets to obtain insulating films. If a DC power source is used to sputter and deposit insulation film, the insulation film will block positive ions from entering the cathode, forming a positive ion accumulation layer, which is prone to breakdown and ignition. After depositing an insulating film on the anode, electrons are blocked from entering the anode, resulting in the phenomenon of anode disappearance. When using an RF power source to coat insulation film, due to the alternating polarity of the electrodes, the positive charges accumulated on the cathode in the first half of the cycle will be neutralized by electrons in the second half of the cycle, and the electrons accumulated on the anode will be neutralized by positive ions. The opposite process in the second half cycle can eliminate the accumulation of charges on the electrode, and the discharge process can proceed normally.
2.High frequency electrodes generate self bias. In the RF device with a flat electrode structure, the high-frequency electrodes in the circuit using capacitive coupling matching generate self bias voltage. The huge difference between the electron migration speed and ion migration speed in discharge enables electrons to achieve a greater movement speed at a given time, while the slower ion speed causes accumulation. The high-frequency electrode is at a negative potential for most of each cycle, resulting in a negative voltage on the terrain, which is the phenomenon of self bias of the high-frequency electrode.
The self bias generated by the RF discharge electrode accelerates the ion bombardment of the cathode electrode to continuously emit Secondary electrons to maintain the discharge process, and the self bias plays a similar role to the cathode drop in DC glow discharge. Although using a RF power supply, the discharge can be stable due to the self bias voltage generated by the high-frequency electrode reaching 500-1000V.
3. Radio frequency discharge plays an important role in the atmospheric pressure glow discharge and dielectric barrier glow discharge introduced later.
Post time: Jun-21-2023