Wet Silicon Etching with Aqueous Amine Gallates

A safe, aggressive formulation is described for wet anisotropic etching of single-crystal silicon. This etchant contains ethanolamine, gallic acid, water, pyrazine, peroxide, and a surfactant, and achieves etch rates of up to 140 μm/h on (100) Si, stopping on high boron concentrations (>3E19 atoms/cm 2 ). The etchant addresses safety and disposal concerns, and supersedes ethylenediamine formulations for the fabrication of silicon structures