Pulsed-aerosol assisted low-pressure plasma for thin film deposition

Abstract

Plasma-enhanced chemical vapor deposition (PE-CVD) is intensively studied and developed to form (multi-)functional thin films. Generally produced in gases or vapors of thermodynamically stable and chemically inert precursors, aerosol assisted plasma process becomes an alternative as it enables to inject various liquid solutions independently of these characteristics. This study examines the case of pentane aerosols injected in pulsed mode in a low-pressure RF plasma. It produces diamond-like carbon thin films with material balance larger than those obtained in gaseous processes. Here, the deposition process is controlled by the pulsed injection. Indeed, the dynamics of thin film deposition result in time-dependent mechanisms at the pulse scale related to the temporary increase of the working pressure and the presence of liquid droplets in the plasma volume. Hence, thin film deposition is controlled by plasma-surface as well as plasma-droplets interactions. Consequently, aerosol-assisted plasma processes are really relevant for the deposition of (multi-)functional coatings.