Controlled Nucleation Aerosol Reactors: Production of Bulk Silicon

A new type of aerosol reactor is described. By controlling the rate of gas phase reactions such that vapor diffusion to existing particles is favored over homogeneous nucleation, a small number of seed particles can be grown to supermicron sizes. A model for the influence of growing particles on the rate of homogeneous nucleation has been used to design a reactor for the production of silicon particles by thermal decomposition of silane gas. Particles as large as 9 μm mass median diameter have been grown in this two-stage reactor. Silicon aerosol yields ranging from 70% to 83% have been achieved with this system.