Effects of gas flow on particle growth in silane RF discharges

The effects of gas flow on particle growth in silane RF discharges in a pla sma chemical vapor deposition (PCVD) reactor with a shower-type powered ele ctrode are studied using an in situ two-dimensional polarization-sensitive laser-light-scattering method. Particle growth depends on both the producti on of short-lifetime radicals and the loss of neural clusters in the radica l production region around the plasma/sheath boundary near the powered elec trode. Gas now of a velocity above about 6 cm/s is effective in suppressing particle growth because of increase in loss of neutral clusters, Moreover, particles larger than 120 nm in size that flow to the plasma/sheath bounda ry near the grounded electrode are found to pass through the sheath. This i mplies that such particles may deposit on film surfaces for PCVD reactors w ith the shower-type powered electrode.