Particles in silicon deposition discharges

The causes of particle growth in silane discharges, and of their escape to growing devices, are discussed. The relation between particle densities, sizes, and escape to the electrodes in an experimental reactor versus those expected (versus location) in large device-production reactors are explained. Available particle growth, density, and escape data is briefly reviewed and explained. In particular, the important distinction between particles drifting with the gas flow and those trapped at the downstream edge of the plasma is clarified. The very important role of thermophoretic forces is discussed, particularly its influence on the size of particles that incorporate into devices. Methods are suggested to mitigate particle incorporation into devices, and to prevent major particle buildup at the downstream end of a reactor.