Plasma deposition of amorphous carbon films on copper

Abstract

The plasma source ion implantation (PSII) technique was used in an attempt to promote diamond formation on a copper substrate via the so-called carbon-implantation-out-diffusion (CIOD) method. Carbon films were deposited on copper substrates in DC and pulsed plasma modes at temperatures and substrate bias voltages (BV) ranging from room temperature (RT) to 950°C and 0 to −30 kV, respectively. All carbon films deposited in the DC-plasma mode at 800–950°C with a BV up to 10 kV exhibited G-band and D-band Raman shifts typical of polycrystalline graphite. Very similar Raman spectra were also obtained from carbon films deposited in the pulsed plasma mode at 800–950°C and a BV up to −30 kV. The Raman spectral shape of the carbon film deposited at RT and −300 V in the pulsed plasma mode showed an asymmetric broad single peak typical of an amorphous diamond-like carbon film with G-band peak shifted toward the lower frequency end at 1520 cm −1 from the original graphite G-line position at 1580 cm −1. No trace of crystalline diamond, signatured by a distinct sharp peak at 1332 cm −1, was found under the experimental conditions examined. Results from XPS analyses were consistent with those of the Raman studies.