Controlled Growth of Ni Particles on Si(100)1a

Ni particles were grown on Si(100) by MOCVD from Ni(η5-C5H4Me)2 in the presence of H2. There is an induction period which is a function of the precursor flux. The Ni particle size is a function of the deposition time and precursor flux. For example, with precursor held at 47 °C, the particle size increases from 140 nm (5 min) to 180 nm (10 min) to 260 nm (20 min) as the deposition time is increased. TiCl4 surface treatment (a) and gas-phase addition of H2O (b) were explored further to influence growth. Both methods increase the growth rate as measured by the Ni(111) XRD peak intensity. (a) The TiCl4 reacts with surface OH groups to form TiO2 islands which act as nucleation sites for Ni growth. A 5 min exposure to TiCl4 results in large (1 mm) amorphous and oriented crystalline TiO2 islands. The Ni crystals first saturate the TiO2 islands and then break off to form individual islands. (b) The gas-phase addition of H2O into the carrier gas stream results in initial formation of large particles which later break up into smaller particles. The size and number of particles are functions of the concentration of H2O in the gas phase.