Ellipsometric study of a-Si:H thin films deposited by square wave modulated rf glow discharge

Lloret, A.
Bertran Serra, Enric
Andújar Bella, José Luis
Canillas i Biosca, Adolf
Morenza Gil, José Luis

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Publication date

October 2012

DOI

10.1063/1.347343

Publisher

AIP Publishing

Journal

Journal of Applied Physics

Abstract

Thin films of hydrogenated amorphous silicon (a‐Si:H), deposited by square wave modulated (SQWM) rf silane discharges, have been studied through spectroscopic and real time phase modulated ellipsometry. The SQMW films obtained at low mean rf power density (19 mW/cm2) have shown smaller surface roughness than those obtained in standard continuous wave (cw) rf discharges. At higher rf powers (≥56 mW/cm2), different behaviors depending on the modulating frequency have been observed. On the one hand, at low modulating frequencies (<40 Hz), the SQWM films have shown a significant increase of porosity and surface roughness as compared to cw samples. On the other, at higher modulating frequencies, the material density and roughness have been found...