Effects of Ar addition on breakdown voltage in a Si(CH3)2(OCH3)2 RF discharge

We present detailed measurements on breakdown voltage (Vf) in a RF discharge with Si(CH3)2(OCH3)2 gas diluted with Ar. When Ar concentration (PAr) is increased, the Vf gradually decreases up to PAr = 50 %, and then is followed by a drastic decrease. The PAr dependence of Vf is well explained by a feature of the ion-induced secondary electron emission coefficient (γ) deduced from measured Paschen curves. A drastic increase in Ar ion flux with PAr induces high emission of electrons from cathode surface, resulting in lowing Vf.