Pulsed Aerosol-Assisted Low-Pressure Plasma for Thin-Film Deposition

Abstract

Plasma-enhanced chemical vapor deposition is a well-developed technique that is commonly applied in the preparation of thin films. However, this technique is limited to thermodynamically stable and chemically inert precursor gases or vapors. Recently, pulsed aerosol-assisted plasma processes have emerged as an advantageous alternative that allows for the injection of various liquid solutions in the plasma, regardless of their properties. This study examines the production of thin films by pulsed injection of pentane aerosols into a low-pressure RF capacitively coupled plasma. This technique produces thin films with high material balance and a high degree of control by adjusting the pulsed injection parameters. At the pulse scale, pulsed injection induces a temporary increase in the working pressure, resulting in time-dependent mechanisms that can affect the dynamics of thin-film deposition at the process scale. Overall, the results show a key role of droplets and their kinetics (ballistic transport, vaporization kinetics, electrostatic confinement). Hence, to efficiently apply this method in the preparation of (multi-)functional coatings, the aerosol must be carefully characterized.