Spatially resolved SiF and SiF2 densities in inductively driven dischargescontaining C2F6 and C4F8

Laser-induced fluorescence was used to measure the spatially resolved SiF a nd SiF2 radical densities in inductively driven discharges containing fluor ocarbon gases. Measurements of the spatially resolved SiF and SiF2 densitie s were performed in C2F6 and C4F8 discharges as functions of the induction coil power, pressure, and bias power above a silicon surface. The SiF densi ty had a maximum at a radial distance of 2-3 cm from the center of the plas ma, and then monotonically decreased towards the edge of the plasma region. While the density was a function of the plasma parameters, the general sha pe of the SiF spatial distribution was generally independent of the plasma conditions and gas. The SiF2 density had a maximum at a radial distance of approximately 7 cm from the center of the plasma. At this location, the SiF 2 plasma-induced optical emission was approximately 10% of the value in the center of the discharge. The SiF2 spatial distribution was dependent on th e induction coil power. The location of the peak in the SiF2 density did no t depend on the plasma confinement structures or material. (C) 2001 America n Institute of Physics.