Atmospheric Pressure Radio-Frequency DBD Deposition of Dense Silicon Dioxide Thin Film
Résumé
Radio-frequency (RF) homogeneous dielectric barrier discharge (DBD) is compared to low frequency glow DBD to make silicon oxide from Ar/NH3/SiH4. RF-DBD is a more powerful discharge, and the growth rate is not limited by precursor dissociation rate but by powder formation. Powders are not deposited in the plasma zone but in the post-discharge due to their trapping by the electric field. Modulation of the RF-DBD is a useful solution to avoid powder formation. Powders are systematically avoided if the plasma energy during time on stays below 750 µJ. RF-DBD modulation also increases the growth rate twofold compare to continuous RF. The optimum growth rate without powder corresponds to a short Ton to limit precursor dissociation, a long Toff to enhance diffusion and a fast repeat frequency to increase deposition rate.