Smooth etching of silicon using TMAH and isopropyl alcohol for MEMS applications

Etching of silicon plays an important role in the field of micromachining. In this study, etching was performed on (1 0 0), (1 1 0) and (1 1 1) silicon using tetramethylammonium hydroxide (TMAH). The roughness of the etched silicon surface was studied as a function of the etching parameters. Etching was carried out at three different temperatures with varying solution concentrations with and without isopropyl alcohol. Emphasis was placed on the roughness of the silicon surface obtained after etching. It was observed that roughness is highly dependent on the solution concentration and temperature. Based on the experimental results and theoretical considerations, the etching mechanism has been explained.