Pulsed plasma enhanced chemical vapor deposition from CH2F2, C2H2F4, and CHCIF2

Pulsed plasma enhanced chemical vapor deposition films have been grown from C2H2F4, CH2F2 , and CHClF2. C-1s x-ray photoelectron spectroscopy (XPS) indicates a prevalence of C-CF species in the films from C2H2F4 and CH2F2, whereas CF2 species dominate the films from CKClF2. The CFx species distributions for the films are largely controlled by the competition between CF2-producing and HF elimination reactions in the pulsed plasmas. Dominance by HF elimination produces films with high C-CF and CF concentrations (e.g., CH2F2), whereas dominance by CS-producing reactions leads to films with higher CF2 concentrations (e.g., CHClF2). The % CF3 in the film is lowest for the precursor having the lowest F:H ratio, CH2F2 Little or no hydrogen was detected in the deposited films. Thermal degradation of films from C2H2F4 and CH2F2, as probed by solid-state nuclear magnetic resonance (NMR) spectroscopy, shows a loss through CB detachment and HF elimination, pulsed plasma films from all three precursors gave dielectric constants of 2.4, with loss tangents on the order of 10(-2). Dielectric measurements of pulsed plasma films from hexafluoropropylene oxide (HFPO) gave a dielectric constant of 2.0 +/- 0.1 with a loss tangent of 0.009.