Fabrication of Sub-10 nm Planar Nanofluidic Channels Through Native Oxide Etch and Anodic Wafer Bonding

A simple, multiple-hydrofluoric (HF)-dip process is developed and characterized to etch native silicon-dioxide (SiO₂) to obtain shallow silicon trenches. The room-temperature SiO₂ grow-etch-grow process yields an etch rate of ~ 1 nm/HF-dip with atomically smooth trench surface. Low-temperature, low-voltage anodic bonding yields sub-10 nm deep planar nanochannels with aspect ratios as small as 0.002.