Deposition parameters and surface topography of a-Si:H thin films obtained by the RF glow discharge process

The surface topography of glow discharge a-Si:H thin films has been studied here through the evaluation of the related statistical characteristics which are: the root mean square roughness (σ) and the autocovariance length (Lc). It is shown that some factors of the film deposition process greatly affect their respective values, modifying the film surface morphology. An high deposition rate (r), increases markedly both σ and Lc while an increase of the substrate temperature (T_s) leads to a reduction of their respective values. The use of an high ion bombardment in the plasma during the deposition process further reduces σ but leads to a noticeable increase of Lc.