Formation of nanocrystalline silicon dots from chlorinated materials by RF plasma-enhanced chemical vapor deposition

Abstract

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 (SiCl 4) and H 2 mixture. The nc-Si dots were directly formed on thermally-grown SiO 2/c-Si at low temperatures of 150–200 °C. 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, SiCl x and the chemical stability of chlorine-terminated surface under hydrogen plasma. Not only the plasma conditions but also the surface chemistry of th-SiO 2 determine the dot density.