Pulsed plasma-enhanced chemical vapor deposition from CH2F2, C2H2F4, and CHClF2

Pulsed plasma enhanced chemical vapor deposition films have been grown from 1,1,2,2-${\mathrm{C}}_{\mathrm{2}}{\mathrm{H}}_{\mathrm{2}}{\mathrm{F}}_{\mathrm{4}},$ ${\mathrm{CH}}_{\mathrm{2}}{\mathrm{F}}_{\mathrm{2}},$ and ${\mathrm{CHClF}}_{\mathrm{2}}.$ $\mathrm{C}\text{\hspace{0.05em}1s}$ x-ray photoelectron spectroscopy indicates a prevalence of $\underset{¯}{\mathrm{C}}\mathrm{–CF}$ species in the films from ${\mathrm{C}}_{\mathrm{2}}{\mathrm{H}}_{\mathrm{2}}{\mathrm{F}}_{\mathrm{4}}$ and ${\mathrm{CH}}_{\mathrm{2}}{\mathrm{F}}_{\mathrm{2}},$ whereas ${\mathrm{CF}}_{\mathrm{2}}$ species dominate the films from ${\mathrm{CHClF}}_{\mathrm{2}}.$ The ${\mathrm{CF}}_x$ species distributions for the films are largely controlled by the competition between ${\mathrm{CF}}_{\mathrm{2}}$ -producing and HF elimination reactions in the pulsed plasmas. Dominance by HF elimination produces films with high $\underset{¯}{\mathrm{C}}\mathrm{–CF}$ and CF concentrations (e.g., ${\mathrm{CH}}_{\mathrm{2}}{\mathrm{F}}_{\mathrm{2}}\mathrm{),}$ whereas dominance by ${\mathrm{CF}}_{\mathrm{2}}$ -producing reactions leads to films with higher ${\mathrm{CF}}_{\mathrm{2}}$ concentrations (e.g., ${\mathrm{CHClF}}_{\mathrm{2}}\mathrm{).}$ The % ${\mathrm{CF}}_{\mathrm{3}}$ in the film is lowest for the precursor having the lowest F:H ratio, ${\mathrm{CH}}_{\mathrm{2}}{\mathrm{F}}_{\mathrm{2}}.$ Little or no hydrogen was detected in the deposited films. Pulsed plasma films from all three precursors gave dielectric constants of 2.4, with loss tangents on the order of ${10}^{\text{−2}}.$ Dielectric measurements of pulsed plasma films from hexafluoropropylene oxide gave a dielectric constant of 2.0±0.1 with a loss tangent of 0.009.