Effectiveness of plasma diagnostic in ultra high frequency and radio frequency hybrid plasmas for synthesis of silicon nitride film at low temperature

Abstract

This work presents a systematic plasma diagnostic approach for plasma processing using radio frequency (RF) and RF/UHF (ultra high frequency) hybrid plasmas. The present work also studies the influence of frequency on the deposition of Hydrogenated silicon nitride (SiNx: H) film using N2/SiH4/NH3 discharges. Analysis of data reveals that the UHF power addition to RF is quite effective in the plasma and radicals formation in different operating conditions. For the diagnostics, we have used optical emission spectroscopy, vacuum ultraviolet absorption spectroscopy, and RF compensated Langmuir probe. The presented diagnostic method directly exploits the optimized condition for fabricating high-quality silicon rich nitride (SiNx: H) thin film, at low temperature. With the help of hybrid plasmas, it is possible to fabricate SiNx: H film with high transparency ∼90%.