Pulse current generator with improved waveform fidelity for high-voltage capacitively coupled plasma systems

This paper proposes a current source-type pulse generator circuit to improve load voltage waveforms by solving the voltage ringing problem of capacitively coupled plasma systems. The voltage source-type pulse power supplies used in the plasma industry have short-circuit currents and voltage ringing problems with capacitively coupled plasma loads. The current source-type pulse generator proposed in this paper can solve these problems. The proposed circuit consists of four detailed circuits: bias current generator, bias current modulator, slope current generator, and slope current modulator. They form two constant currents at the DC link, and output two pulse currents to the load. These output currents contribute to generating the plasma load voltage required by the capacitively coupled plasma process. The proposed circuit is verified by a PLECS simulator and a laboratory-scale hardware system. To check the improvement of the output waveform, a voltage source-type pulse generator and the current source-type pulse generator are tested under the same experimental conditions. The results are represented by load voltage and current waveforms. In addition, the entire system of the current source-type pulse generator is designed and verified by simulation and experimental results. The resulting output waveforms meet the process requirements, and the obtained results demonstrate that the proposed current source-type pulse generator circuit can be suitably used for capacitively coupled plasma loads.