Influence of current modulation waveform on polycrystalline diamond film deposition using modulated induction thermal plasmas—numerical and experimental studies

Abstract

In this paper, the influence of amplitude-modulated coil current waveform on polycrystalline diamond deposition was studied using modulated induction thermal plasma (M-ITP) with numerical and experimental approaches. The M-ITP is useful in undertaking the nucleation of diamond particles necessary for the first stage of diamond film deposition. First, numerical thermo-fluid calculations were conducted for Ar M-ITP with CH4/H2 feedstock gas to investigate the influence of a modulation waveform on particle fluxes of different hydrocarbon species onto a Si substrate. Furthermore, experiments were performed to fabricate polycrystalline diamond film deposition using M-ITP with different modulation waveforms. The modulation waveform for the coil current was set as a rectangular waveform, a saw-tooth waveform and a reverse saw-tooth waveform in the calculations and the experiments. The experimental results showed that the saw-tooth M-ITP provided a higher deposition rate, of 2.05 µm h−1, than other waveforms. This could be attributed to the higher fluxes of neutral hydrocarbons in the saw-tooth M-ITP according to the calculation results.