Experimental investigation of powder formation in SiF4-H2 and SiH4-H2 Discharges

Radiofrequency discharges (13.56 MHz) of SiH4-H2 and SiF4-H2 mixtures are widely used in plasma enhanced chemical vapor deposition (PECVD) of hydrogenated amorphous silicon films, employed in photovoltaic and electronic applications. Since powder formation in these low pressure r.f. discharges is a serious concern, in the last years, great attention has been placed on the particle genesis study. In this work, we report on preliminary results on He-Ne laser Mie scattering in SiF4-H2 plasma. A comparison with results obtained in SiH4-H2 plasma is also reported.