Chemical and Physical Effects of the Carrier Gas on the Atmospheric Pressure PECVD of Fluorinated Precursors

TL;DR

This study examines how different carrier gases, argon and helium, influence the chemical reactions, film composition, and surface morphology during atmospheric pressure PECVD of fluorinated coatings, revealing gas-specific effects on film properties.

Contribution

It provides new insights into how carrier gases affect plasma chemistry, film composition, and surface morphology in PECVD processes using fluorinated precursors.

Findings

Argon increases fragmentation and surface roughness.

Helium reacts with oxygen impurities forming CxFyOz compounds.

Argon discharge streamers enhance surface hydrophobicity.

Abstract

The atmospheric pressure PECVD deposition and texturization of hydrophobic coatings using liquid fluorinated C6F12 and C6F14 precursors are investigated. The effect of the carrier gas (argon and helium) is discussed in terms of the behavior of the gas phase and of the characteristics of the deposited film. Mass spectrom-etry measurements indicate that the fragmentation is higher with argon while helium reacts very easily with oxygen impurities leading to the formation of CxFyOz compounds. These observations are consistent with the chemical composition of the films determined by XPS and the variation in the deposition rate. Moreover, the streamers present in the argon discharge affect the morphology of the surface by increasing the roughness, which leads to the increase in the hydrophobicity of the coatings.