CVD growth of Si nanocrystals on dielectric surfaces for nanocrystal floating gate memory application

Initial stages of growth of silicon on dielectric surface proceeds through Volmer-Webber growth mode (through island formation) and coalescence of islands to form a continuous thin film layer. Growth of silicon nanocrystals on dielectric surface can be achieved by controlling the nucleation and growth kinetics of these nanocrystals on the dielectric surface. In this study, we present CVD growth of Si nanocrystals on oxide, oxynitride and nitride surfaces using silane based chemistry. The effect of process conditions such as deposition temperature, precursor flow rate, cartier gas on nanocrystal incubation time, size and density of nanocrystals was studied. The nucleation and growth rate of the silicon nanocrystals is also a strong function of the surface chemistry, surface structure and strain in the dielectric film. We have studied the effect of oxide deposition temperature and surface pretreatments on the nucleation and growth characteristics of the silicon nanocrystals.