Experimental and Modeling Studies on the Nucleation and Growth of

Silicon Nanoparticles from the Vapor Phase

Mark T. Swihart

Department of Chemical Engineering

University at Buffalo (SUNY), Buffalo, NY 14260, USA

Synthesis of semiconductor nanoparticles is of great interest due to their unique, size-dependent optical and electronic properties. Controllable production of nanoparticles of desired size and composition would benefit from an improved understanding of particle nucleation and growth, and from the ability to quantitatively model these processes. On the other hand, particulate contamination due to particles nucleated within processing equipment is an important source of yield loss in microelectronics manufacturing. To control this unwanted homogeneous nucleation of particles, again, we must understand and be able to quantitatively model the nucleation process. We are developing chemical kinetic models for the nucleation of silicon particles. These models allow us to identify key reaction pathways for nucleation and to predict particle nucleation rates and incorporate them into aerosol dynamics models of processing equipment that include descriptions of particle growth, coagulation, and transport. At the same time, we are conducting experiments on the vapor-phase synthesis of semiconductor nanoparticles in a laser-driven reactor system. We have succeeded in producing sub-10-nm diameter non-agglomerated crystalline silicon nanoparticles, as well as agglomerates with comparable primary particle size in much higher concentrations. This talk will present a brief overview of our work in these areas, including:

(1) Manual and automated construction of chemically detailed models of the nucleation of silicon nanoparticles during gas-phase thermal decomposition of silane

(2) Incorporation of these models into aerosol dynamics models to predict particle concentrations and size distributions in simple reactor geometries;

(3) Production of silicon nanoparticles in our laser-driven aerosol reactor system and dependence of nanoparticle size and properties on reaction conditions; and

(4) Post-processing and characterization of these silicon nanoparticles to achieve photoluminescence properties useful for applications in microelectronics, nanophotonics, and bio-imaging.