Controllable shrinking of silicon oxide nanopores by high temperature annealing

This paper presents a novel method for fabricating silicon oxide nanopores. First, pores of 80–400 nm were fabricated in a free-standing silicon membrane by anisotropic wet etching process. After thermal oxidation of 90 nm silicon oxide, the pores can be reduced to 35–300 nm. Finally, high temperature annealing promotes the viscous flow of the silicon dioxide membrane and results in shrinking the pores to sub-15 nm, with an estimated precision of 1 nm. Our results are in agreement with the surface-tension-driven model.