Preferential growth of Si nanocrystals in SiO2/Si/SiO2 sandwich structure

SiO2/Si/SiO2 sandwich structure was fabricated by sputtering deposition. Many columnar {1 1 1} Si nanocrystals containing nanotwins were observed perpendicular to Si/SiO2 interface after annealing. The preferential growth of {1 1 1} Si nanocrystals can attribute to two reasons, namely the nucleation at Si/SiO2 interface and the lowest surface energy of {1 1 1} planes. The formation of nanotwins is the result of the internal stress during the growth progress of nanocrystals.