Metal-assisted chemical etching for realisation of deep silicon microstructures

Metal-assisted chemical etching process is exploited to realise deep-etched silicon structures. Gold as the noble metal, hydrogen peroxide and hydrofluoric acid solutions are used to achieve deep vertical structures. By controlling the solution concentrations, thickness and morphology of the deposited metal, several hundred micrometre-sized silicon structures can be achieved. This method, upon achieving more controllability and repeatability, can be a good substitute for dry etching, due to its high etch-rate, low-cost materials and non-requirement to complex equipment. In this work, the effect of different etching parameters on the etching process is studied to gain more control over the etching conditions.