Anion Reactions in Silane Plasmas

Published

May 1, 2002

Author(s)

Alan Gallagher, A A. Howling, C Hollenstein

Abstract

Previously reported and unpublished measurements of Si_xH_m anions and electrons in the afterglow of silane discharges are analyzed here.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 SiH_m anions. Measured afterglow electron decay and SiH_m 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 (K_x) and mutual neutralization (k_MN) rate coefficients. However, the x dependence of the k_x required to fit the data is surprising. these conclusions have major consequences on particle-nucleation models for silane discharges.

Citation

Journal of Applied Physics

Volume

91

Issue

No. 9

Pub Type

Journals

Keywords

amorphous, discharges, silane, silicon

Citation

Gallagher, A. , Howling, A. and Hollenstein, C. (2002), Anion Reactions in Silane Plasmas, Journal of Applied Physics (Accessed April 19, 2024)