Selective Si growth on partially desorbed SiO2/Si(001) surfaces

We used in situ reflection high energy electron diffraction and ex situ atomic force microscopy to study the selective epitaxial growth of Si structures on partially desorbed SiO2/Si surfaces. The low temperature desorption of the oxide layer results in the formation of square apertures oriented along 〈110〉 directions. The selective growth of Si from silane is shown to evolve from (001) truncated pyramids toward the formation of complete pyramids limited by {113} facets. A model based on the anisotropic diffusion of silane is proposed to explain the formation of these Si structures.