A Surface Micromachining: HNA Etchant for Stiction-free Release of Micro/Nanomechanical Structures

We report a simple and efficient silicon wet etchant HNA (Hydrofluoric acid, Nitric Acetic acid) for the stiction free release of nitride/metal micro/nanomechanical structures. The concentration was varied with aim developing slow etch rate, which could be utilized to suspend micron sub-micron cantilever fixed beam rate found decrease in HF increase HNO3 concentrations. Smooth surface high selectivity are obtained case content. 440 nm/minute successfully nitride cantilevers structures 500 nm, 2 µm 5 widths varying lengths. resonance frequency suspended characterized by Laser Doppler Vibrometer is close agreement COMSOL simulated resonating frequencies proving that etching process has been precise without changes dimensions. In addition, generated used releasing chrome/gold nanobeams as well any damage metal layers.