TMAH Etching of Silicon Wafer for Detector Fabrication

Anisotropic wet etching of high resistivity silicon by TMAH for the fabrication of large area silicon radiation detectors is studied in this work. TMAH is widely applied in microelectronics and micromechanical fabrication etching low resistivity silicon, whereas the etching of high resistivity silicon was seldom studied by the industry. This work focused on the research of TMAH etching of high resistivity lager area silicon wafer aiming at its application in silicon radiation detector fabrication. We investigated the etching properties of TMAH of 4 inch (111) silicon wafers. Various parameters combinations were explored, such as TMAH solution concentration of 25wt%, 15wt% and 5wt%, and temperature of 95 °C, 90 °C and 85 °C. Etch rate, etch uniformity and silicon surface roughness were observed.