We have investigated silicon particles formed in an inductively coupled plasma (ICP) system and have measured their structural properties by electron microscopy. ICP silane plasmas are shown to be an interesting and versatile source of nanoparticles. Three regimes are mapped out: a regime of no observable particle growth at the lowest pressures, a regime of polydisperse and agglomerated particles at the highest pressures, and a regime yielding highly monodisperse particles at intermediate pressures. Our results suggest that an ICP allows this unique production of monodisperse nanoparticles at high concentrations. The particle size can be controlled from 15 to 200 nm and is determined by the plasma on time. For short plasma times, particle growth appears to be due primarily to coagulation, while in the second phase particle growth is attributed primarily to surface deposition. For H2 dilutions less than 92%, the growth rate is almost independent of H2 partial pressure. Transmission electron micrographs, however, indicate that the addition of hydrogen decreases the particle density. At higher dilution ratios, polycrystalline particles are obtained. Under all other conditions the particles are amorphous.

Particle generation in thermal chemical vapor deposition ͑CVD͒ processes can lead to the formation of contaminant particles that affect film properties and eventually device performance. This article reports on measurements of particle formation during low-pressure CVD of SiO 2 from silane and oxygen. Measurements of aerosol size distributions were made using a particle beam mass spectrometer ͑PBMS͒ and were carried out at pressures and temperatures ranging from 0.5 to 2.0 Torr ͑67-267 Pa͒ and 200-800°C, using an O 2 /SiH 4 ratio of 20. We found that within this parameter space, there are three different particle formation regions and a particle-free region. The particle formation regions include an explosion region ͓200-300°C, Pտ1.0 Torr ͑ϳ80 Pa͔͒, an unsteady region ͓400-600°C, Pտ0.8 Torr ͑ϳ107 Pa͔͒, and a steady region ͓700-800°C, P տ0.6 Torr ͑ϳ67 Pa͔͒. PBMS size analysis in the steady region shows that the size distributions are bimodal with one mode around 7 nm in diameter and the other around 20 nm, which is in reasonable agreement with transmission electron microscopy measurements. A numerical model was developed to simulate particle nucleation and growth in this system. The model predicts that for a given temperature, there exists a critical pressure above which abundant particle formation occurs and below which particle production is insignificant. The pressures for which particle formation was measured with the PBMS are in good agreement with model predictions, and measured and calculated particle sizes are in reasonable agreement. It is also found that there is a correlation between particle concentration and film surface morphology, dielectric constant, and currentvoltage characteristics of the film.