Figure 2From: Nanofabrication on monocrystalline silicon through friction-induced selective etching of Si3N4 maskVariation of etching depth of Si/Si 3 N 4 sample with etching period in HF solution. After etching for 30 min, Si was exposed on the scratched region while a residual Si3N4 mask of 15 nm in thickness was still covered on the original region.Back to article page