Reaction Studies between Fluorocarbon Films and Si Using Temperature-Programmed X-Ray Photoelectron and Desorption Spectroscopies

Surface structure of plasma-polymerized fluorocarbon thin film on Si and gas desorption were concurrently studied as a function of temperature between 20 and 700° C using temperature-programmed X-ray photoelectron spectroscopy with a residual gas analyzer. The films, consisting of CF3, CF2, CF and C-CF x bonds, with the F/C ratio of 1.7 were found to be stable up to 200° C and to thermally decompose above 200° C. SiF4 desorption, following gradual pyrolysis with decrease in CF3, CF2 and CF bonds due to desorption of fluorocarbon gases, was observed for F/C ratios ranging from 1 to 0.1. The pyrolytic process of the film and the thermal reaction with Si substrates were further discussed based on results of additional desorption and ion-induced reaction experiments.