Production mechanism and reactivity of the SiH radical in a silane plasma

Abstract

SiH free radicals in a dc multipole post-discharge plasma were analyzed using laser-induced fluorescence. The cross section for SiH formation from 40–70 eV electron impact induced dissociation of SiH4 was measured to be (10 ± 5) × 10−17 cm2. At the instant of its formation in its X2Π ground state, the rotational temperature of the SiH radical is 950 K. This temperature subsequently relaxes by collisions with SiH at a collisional relaxation rate k = (9 ± 2) × 1013 cm3/mole s. Quenching of the A2Δ electronic state of SiH was found to be negligible below 0.3 Torr. The primary reaction path for destruction of the SiH radical was observed to be via: SiH + SiH4 → products, k = 2 × 1012 cm3/mole s.