Nucleation and growth analysis of microcrystalline silicon by scanning probe microscopy: substrate dependence, local structural and electronic properties of as-grown surfaces

Nucleation and growth of hydrogenated microcrystalline silicon films are investigated by scanning probe microscopy and spectroscopy of as-grown films. We measure highly doped films grown on oxidized silicon and discuss nucleation of crystallites in comparison with hydrogen-passivated substrates. It turns out that the oxidized substrate mediates nucleation. This mechanism is preferred over nucleation on hydrogenated amorphous silicon. For films as thin as a few nanometers we demonstrate that scanning tunneling microscopy and spectroscopy are capable of spatially resolving structural and electronic surface properties. Amorphous and microcrystalline surface elements are distinguished by different types of tunneling spectra showing by a factor of ∼5 a larger rectification for crystallites.