Development of catalytic etching using dual materials

In this study we presents an effective and simple process for forming multi-level vertical structures on a (100) silicon wafer. The dual materials including gold and platinum was employed as catalytic material in the etching process. We employed an etchant solution consisting of 4.6 M hydrofluoric acid, 0.44 M hydrogen peroxide, and isopropyl alcohol to produce microstructures at an etching rate of 0.294 μm/min and 0.648 μm/min during only gold (Au) and platinum (Pt) film, respectively. For the catalytic etching process with 10 nm-thick Au and Pt, the etching rate yield from Au film was increased to that generated from the etching process with single Pt film. In the meantime, the etching structure under Pt film became not obvious in the dual materials etching process. For the sample with 10 nm Au and 11 nm Pt, the significant etching produced on both Au and Pt region.