Electron-impact silane dissociation and deposition rate relationship in the PECVD of microcrystalline silicon thin films

E. Amanatides; D.E. Rapakoulias; D. Mataras

doi:doi:10.1051/jp4:2001390

Issue		J. Phys. IV France Volume 11, Number PR3, Août 2001 Thirteenth European Conference on Chemical Vapor Deposition


Page(s)		Pr3-715 - Pr3-722
DOI		https://doi.org/10.1051/jp4:2001390

Thirteenth European Conference on Chemical Vapor Deposition

J. Phys. IV France 11 (2001) Pr3-715-Pr3-722
DOI: 10.1051/jp4:2001390

Electron-impact silane dissociation and deposition rate relationship in the PECVD of microcrystalline silicon thin films

E. Amanatides, D.E. Rapakoulias and D. Mataras

Plasma Technology Laboratory, Department of Chemical Engineering, University of Patras, P.O. Box 1407, 26500 Patras, Greece

Abstract
An investigation of the relation between silane electron impact dissociation and deposition rates of microcrystalline silicon thin films, has been performed in highly diluted SiH₄ in H₂ discharges, by applying a combination of experimental measurements and modeling of the process. A wide range of frequencies (13.56 MHz - 50 MHz), power densities (11 mW/cm² - 162 mW/cm²) and silane partial pressures (2% - 6%) at two total SiH₄/H₂ pressures of 0.5 Torr and 1 Torr has been studied. In the lower pressure, independent of all other discharge parameters, SiH₄ primary dissociation has been found to be responsible for about 70% of the total silane consumption in the discharge, while a fraction of 12% of the initially produced silicon hydrides are incorporated into the growing film. The increase of pressure leads to a drop of the contribution of the SiH₄ primary dissociation to the total silane consumption and to an increase of the deposition efficiency of the initially produced radicals to a value of 26%. This result is attributed to the production of additional, two silicon atom precursors via secondary gas-phase reactions.