Fast Wet Anisotropic Etching of Si{100} and {110} with a Smooth Surface in Ultra-High Temperature KOH Solutions

摘要

We report the etching characteristics of Si{100} and {110} at ultra-high temperature ranges near the boiling point of KOH solutions. The etching rates of Si {100} and {110} at near the boiling point were 5-9 times and 4-20 times higher than those at 80 deg C in the KOH concentrations of more than 32wt%, respectively. At 145 deg C in 50wt% KOH, we can get a Si{100} smooth surface with a high etching rate of 9.7μm/min and at 135 deg C in 45-47wt%KOH, we can get a Si{110} smooth surface with a ultra-high etching rate of 20μm/min. Arrhenius plots of the etching rates were nearly linear from 80deg C to near the boiling point. It is considered that the activation process in the higher temperature is the same as that in the lower temperature.