STUDY ON INITIAL GROWTH OF PARTICLES IN LOW-PRESSURE AND LOW-POURER GEH4 RF DISCHARGES USING THE HIGH-SENSITIVITY PHOTON-COUNTING LASER-LIGHT-SCATTERING METHOD
H. Kawasaki et al., STUDY ON INITIAL GROWTH OF PARTICLES IN LOW-PRESSURE AND LOW-POURER GEH4 RF DISCHARGES USING THE HIGH-SENSITIVITY PHOTON-COUNTING LASER-LIGHT-SCATTERING METHOD, JPN J A P 2, 37(10B), 1998, pp. 1264-1267
A high-sensitivity photon-counting laser-light-scattering method is ap
plied to obtain information on initial growth of particles formed in l
ow pressure and low power GeH4 RF discharges. Particles of about 1 nm
in size are detected principally around the plasma/sheath boundary nea
r the RF electrode at an early time of 0.2 s after the discharge initi
ation and the corresponding particle density of 2 x 10(11) cm(-3) is a
bout two orders of magnitude higher than ion density. Spatial profiles
of particle amount are very similar to those of Ge emission intensity
which indicates a radical production rate. These results suggest that
short-lifetime radicals such as GeH2, having a high production rate,
are candidates for key species contributing to the nucleation and init
ial growth of particles, even for a low pressure (8-13 Pa) and a low p
ower density (0.04 W/cm(2)). Furthermore, surface reflection probabili
ties of particles 1-12 nm in size, measured after RF-power-off, are fo
und to be more than 80%.