| This dissertation work applied the pulse modulated plasma to the plasma enhanced chemical vapor deposition (PECVD) of two types of dielectric materials: SiO2-like coatings and Teflon-like coatings.; SiO2-like coatings were firstly implemented with continuous plasma. It was proven that three different precursors: hexamethyldisiloxane (HMDSO), 1, 3, 5, 7-tetramethylcyclotetrasiloxane (TMCTS) and octamethylcyclotetrasiloxane (OMCTS) can be used to generate hard, clear and high density SiO2 deposition with coupled high growth rate and low processing temperature via PECVD. Under similar conditions, HMDSO has the lowest growth rate, lowest hardness and highest carbon content; TMCTS has the highest growth rate and hardness, and lowest carbon content; and OMCTS has moderate rates of these deposition qualities, but the best corrosion resistance. Substrate bias seems to have no effect on any deposition quality. High chamber pressure can significantly lower the carbon content in the thin films but does not affect any other qualities; the O2/precursor ratio is the most influential factor among all variables considered in this experiment. The deposition hardness and O:Si ratio always increase with this ratio while the carbon content always decreases. However, different precursors require different optimal ratios to achieve the highest growth rate.; Pulse modulation was introduced into PECVD of SiO2-like coatings and OMCTS was selected as the precursor. It was demonstrated that pulse frequency, duty ratio and peak power have significant effects on deposition qualities. The proper combination of the pulse parameters and other traditional plasma parameters can significantly lower the processing temperature while retaining or even improving other deposition qualities, such as growth rate, corrosion resistance and elemental composition. Hardness is the only sacrifice of the lower time-average power caused by pulsing. Therefore, pulse modulation can effectively expand the possible range of combinations of desired deposition qualities.; Finally, the pulsed plasma was used to implement PECVD of teflon-like coatings. An important discovery in this application is that in addition to pulse period, on-time and on-time peak power, the power level during the off-time is an important factor. The density of CF2 is a function of all these pulse parameters. The best result obtained is up to 67.2% CF2 and a 1.87:1 of F:C ratio when the off-time power level is ∼100--130 W the frequency is several Hz, the on-time peak power is ∼1000 W and the duty ratio is ∼7--10%. |
