Nano-ring-shape growth of fluorocarbon macromolecules during SiO2 etching

A unique nanoscale ring-shape pattern of fluorocarbon macromolecules grown during SiO2 reactive ion etching (RIE) is presented. This pattern was discovered after SiO2 RIE using trifluoromethane (CHF3) and oxygen. Typical dimensions of the ring-type fluorocarbon structure are found to be ∼ 50 nm in diameter, ∼ 10 nm in wall thickness, and ∼ 50 nm in height in this study. The ring-shape structure grows towards a tube-shape structure up to 500 nm. Morphological studies are also presented with various plasma etching parameters. This experiment shows that oxygen-rich RIE etching produces more ring-type structures. This could be used as a nanoscale template for other applications.