Silane dissociation products in deposition discharges

Time-dependent production of higher-silane gases and a-Si:H film are measured relative to decomposed silane in rf and dc, hot and cold cathode, static-gas discharges. From the absence of higher-silane production in very low silane partial-pressure discharges, it is inferred that most higher silanes are produced by gas-phase SiH2-initiated reactions. The higher silanes are thus tracers of SiH2, while the film production traces the fraction of H, SiH, and SiH3 in the initial decomposition. From the measured stable product yields, we deduce that SiH4→SiH2+2H is the dominant electron-collisional dissociation channel.