Low-temperature formation of nanocrystalline silicon (nc-Si) dots is demonstrated by controlling the early stages of a conventional parallel plate RF (13.56 MHz) plasma-enhanced chemical vapor deposition (PE-CVD) in silicon tetrachloride (SiCl4) and H-2 mixture. The nc-Si dots were directly formed on thermally-grown SiO2/c-Si at low temperatures of 150-200 degreesC. The size, height and number density of the dots were controlled by deposition time, pressure, substrate temperature and RF power. These specific features originate from a low sticking probability of deposition precursor, SiClx and the chemical stability of chlorine-terminated surface under hydrogen plasma. Not only the plasma conditions but also the surface chemistry of th-SiO2 determine the dot density.