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

We present detailed measurements on breakdown voltage (V
_f
) in a RF discharge with Si(CH
₃
)
₂
(OCH
₃
)
₂
gas diluted with Ar. When Ar concentration (P
_Ar
) is increased, the V
_f
gradually decreases up to P
_Ar
= 50 %, and then is followed by a drastic decrease. The P
_Ar
dependence of V
_f
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 P
_Ar
induces high emission of electrons from cathode surface, resulting in lowing V
_f
.