Two-dimensional spatial profiles of size and density of particulates grown in RF silane plasmas

Two-dimensional (2-D) spatial profiles of size and density of particulates in RF silane plasmas have been measured simultaneously using a newly developed in situ polarization-sensitive laser light scattering method. Particulates are observed principally in the annular region, around the plasma/sheath boundary near the RF electrode. Their size and density are in ranges of 50~110 nm and 10⁶~10⁸ cm^-3, respectively. Furthermore, larger particulates tend to be localized nearer to the RF electrode and to about 10 mm off the discharge-column-axis. The observed profiles of particulates along the discharge-column-axis can be explained by a balance between electrostatic and ion drag forces exerted on them. Their annular radial profiles may be explained by taking into account that the ion density has the radial distribution, and the electric field around the plasma/sheath boundary has the radial component