Discharge frequency dependence of particulate growth in high frequency silane plasmas

Discharge frequency dependence of growth of particulates is studied in high frequency silane plasmas. Particulates appear earlier after discharge initiation and the increasing rate of their amount in the subsequent phase decreases with increasing the discharge frequency from 3.5 to 28 MHz. Even in the early phase of their formation for all 3.5-28 MHz discharges, particulates grow principally around the plasma/sheath boundary near the powered electrode, where short lifetime radicals are actively generated. For 28 MHz, the density of particulates in the early discharge phase is extremely high (≥10 ¹¹cm³). The latter two features suggest that many short lifetime neutral radicals (such as SiH₂), being produced at a high rate, significantly contribute to the nucleation and initial growth of one particulate, at least, for a relatively high power density of the order of 0.5 W/cm².