Correlation of hydrogen content with the microstructure of a-C:H films

This paper shows the correlation of hydrogen content with the microstructure of a-C:H films. Samples having hydrogen content ranging from ∼3 to 40 at% and varying microstructures have been prepared using the DC-glow discharge of acetylene (C2H2). Infrared absorption spectroscopy was employed primarily for extracting the bonding information, elastic recoil detection analysis was used to measure the total hydrogen concentration and mass spectroscopic thermal effusion was used for studying the thermal stability of the films. Ion-beam-induced release of hydrogen during elastic recoil detection analysis suggests that the kinetics of this release process is related to the total hydrogen content and microstructure of the samples. Significant differences in the mass spectroscopic thermal effusion spectra obtained from soft as well as hard films also reveal that effusion of various species is dependent on the film microstructure, which in turn is governed by the film growth parameters.