Breakdown behavior in radio-frequency argon discharges

The minimum voltage required to break down a discharge Vbrk has long been known to be a strong function of the product of the neutral gas pressure and the electrode separation (pd). This paper investigates the dependence of Vbrk on pd in radio-frequency (rf) systems using experimental, computational and analytic techniques. Experimental measurements of Vbrk in an argon discharge are made for pressures in the range 1–500 mTorr and electrode separations of 2–20 cm. A particle-in-cell simulation is used to investigate a similar pd range and examine the effect of the secondary emission coefficient on the rf breakdown curve, particularly at low pd values. A zero- dimensional global (volume averaged) model is also developed to compare with experimental and simulated measurements of breakdown.