Next-Generation Variable Capacitors to Reduce Capacitance Variable Time Using SiC MOSFETs and p-i-n Diodes in 13.56-MHz RF Plasma Systems

This article introduces a novel method of reducing the capacitance variable time of a vacuum variable capacitor (VVC) impedance matching circuit of 320 V/1 kW/13.56 MHz common to radio frequency (RF) plasma systems. Our method replaces the VVC with an electrical variable capacitor (EVC) that uses power electronics technology to reduce capacitance variable time. Simulation and testing of the proposed circuit showed that the variable time of the EVC was maintained below
$81~\mu \text{s}$
, and that due to the fast switching action of the power semiconductor switch, the proposed circuit can be applied in the impedance matching circuit of high-power and high-frequency RF plasma systems.