Growth of single-crystal SiO2 clusters on Si(001) surface

Abstract

Crystalline SiO2 clusters of nearly square shape were fabricated from amorphous silicon deposited on a clean Si(001) surface, where the deposited silicon was oxidized in the presence of atomic hydrogen and annealed in an O2 atmosphere. The side of these clusters was aligned along the [110] and [11¯0] azimuths of the Si(001) substrate. The crystallinity of the clusters was verified by grazing incidence x-ray diffraction and low-energy electron diffraction. The crystal structure of SiO2 clusters was estimated to be β-tridymite, whose [101¯0] and [0001] axes were parallel to the ⟨110⟩ axes of the substrate Si(001). When the Si(001) surface without deposited amorphous silicon was oxidized by the method described above, single-crystal SiO2 clusters were also prepared. However, the shape, the size, and the number density of the clusters were different from those of the clusters made from the amorphous silicon.