Influence of plasma stimulation on Si nanowire nucleation and orientation dependence

A plasma was introduced during silane-hydrogen VLS nanowire growth on Si (100) substrates and its effect on the nucleation of Au seeded Si nanowires was investigated. Si nanowires were grown in an LPCVD reactor on AU seeded Si (100) surfaces from hydrogen-diluted silane gases under thermal conditions. The [111] oriented epitaxial nanowires were rotated at 45° to the vertical. Plasma excitation was found to significantly enhance the nucleation of [110] nanowires at all temperatures. The density of [110] nanowires for the two-step experiment showed a 4-fold greater density in nanowires. The growth rates of the nanowires were observed to increase under rf plasma excitation. It was also observed that the reduction in [111] nanowire nucleation under plasma excitation also results from the enhanced nucleation of smaller diameter nanowires.