Fabrication of Single-Crystal Silicon Nanoslits with Feature Sizes Down to 4 nm and High Length-Width Ratios

In this paper we report firstly the realization of nanoslits with feature sizes down to sub-4 nm in single-crystal silicon substrate at chip scale. Three-step anisotropic wet etching (TSWE) method was used in the fabrication process and a low-noise current feedback experimental set-up was developed to monitor the slit-opening event in the last step. Individual nanoslit with 3.8 nm width and $3.88\ \mu \mathrm{m}$ length, which means the nanoslit with a length-width ratio more than 1000 was successfully obtained.