| In the experimental portion of this work, carbon films are deposited on substrates of silicon, sapphire and borosilicate glass at beam energies ranging from 500–3500 eV, using Ar+ and Ne+ incident ions, with one sample of each substrate material thermally bonded to the cooled platform and another left in point contact. The films grown on substrates attached to the platform with thermal paste exhibit higher electrical resistivities than those grown on substrates which are left in point contact with the platform. This implies that the sp3 content of the films decreases with increasing substrate temperature. The films deposited on glass are found to have higher electrical resistivities than those grown on sapphire, suggesting that the films grown on glass substrates may suffer more damage than those grown on sapphire. The Raman spectra suggest that the sp3 content of the films grown on backed sapphire substrates follows the same trend as the electrical resistivity.; In the computational portion of this work, the impact of 500 eV Ar +, Ne+ and Kr+ ions on an amorphous carbon target is simulated at incident angles ranging from 0° (normal) to 75°. Findings suggest that amorphous carbon films of the highest sp 3 contents would be grown using neon at grazing incidence. The average sputter yield is found to increase from normal incidence to a maximum at 45° or 60° incidence and to decrease toward grazing incidence. This and other evidence suggests that the fundamental behavior of the sputtering process changes at grazing incidence from that characteristic of the linear cascade regime to that expected for the single-knockon regime. As expected, we find that the sputter yield from the carbon coated tungsten target is dramatically enhanced at normal incidence. As we move toward grazing incidence, the enhancement becomes less significant. Though the average energy of the sputtered carbon atoms is not increased as thought, the average total energy released due to each ion impact is significantly increased. Also, the energy distribution of the sputtered atoms is significantly narrower than that for a plain carbon target. Both of these facts have positive implications for the deposition of high sp3 content amorphous carbon films. (Abstract shortened by UMI.)... |
