Fabrication of nanocrystalline silicon with small spread of particle size by pulsed gas plasma

We have investigated the formation of nanocrystalline Si (nc-Si) in SiH4 plasma using a pulsed-H-2 gas supply by very-high-frequency (VHF; 144MHz) excitation. Nanocrystalline Si is formed in the gas phase of a SiH4 plasma cell by the coalescence of radicals. The particle size of nc-Si is determined by the growth time of nc-Si in the plasma cell. Supplying H-2 into SiH4 plasma enhances nucleation of nc-Si. When the H-2 gas supply is turned off, nucleated nc-Si particles grow larger in SiH4 plasma. In the next cycle of H-2 gas supply; nc-Si particles grown in the previous cycle are pushed out of the cell into the deposition chamber. Using this method, fabrication of nc-Si with a diameter around 8 nm and a narrow spread (+/-1 nm) of particle size was realized.