The influence of thermophoresis effects during deposition of hydrogenated amorphous silicon thin films with nanocrystalline silicon inclusions

Silicon cluster formation is known to occur within silane plasmas when a capacitively-coupled deposition reactor is operated at high gas chamber pressures. These clusters are sensitive to the thermophoretic forces that will, depending on the sign of the thermal gradient, direct them toward or away from the silicon film's growing surface. We have developed a dual-chamber deposition system that produces nanocrystalline silicon particles (roughly 3-5 nm in diameter) in a flow-through reactor, and injects these particles into a separate capacitively-coupled plasma chamber where the amorphous film is produced. The structural, optical and electronic properties of these mixed-phase materials are investigated as a function of the controllable thermal gradient applied across the silane plasma during deposition.