Previously reported and unpublished measurements of SixHm anions and electrons in the afterglow of silane discharges are analyzed here. A model of plasma anion chemistry includes two sources of anions, two possible causes of x-x + 1 anion growth, and mutual-neutralization anion loss. Comparison to pulsed-discharge measuremnts for x=1-6, for a range of discharge times, clearly establishes radical reactions as the primary cause of anion growth; prior estimates generally suggested silane reactions. This comparison also indicates that electron attachment to radicals, not silane, is the largest source of SiHm anions. Measured afterglow electron decay and SiHm signals are also consistent with efficient, low energy electron attachment to radicals, REasonable agreement with the observations is obtained using realistic estimates of the radical density, cation density and the sizes of radical-anion (Kx) and mutual neutralization (kMN) rate coefficients. However, the x dependence of the kx required to fit the data is surprising. these conclusions have major consequences on particle-nucleation models for silane discharges.
Journal of Applied Physics
amorphous, discharges, silane, silicon
, Howling, A.
and Hollenstein, C.
Anion Reactions in Silane Plasmas, Journal of Applied Physics
(Accessed May 29, 2023)