Fluctuations During Anisotropic Etching: Local Recalibration and Application to Si{110}

Based on the previous studies of the etch rate of crystalline silicon in alkaline etchants, we stress the fact that the etch rates can noticeably differ between different research groups. This affects the prediction of the etch front, since the simulators typically use experimental data gathered in one laboratory. Considering the most efficient and accurate simulator currently available for the description of anisotropic etching, namely the continuous cellular automaton (CCA), any such variation in the experimental etch rates requires a time-consuming calibration procedure in order to adjust the atomistic removal rates internally used by the method. Since normally it is possible to directly compare the experimental and simulated etch fronts - without actual knowledge of the variations in the macroscopic etch rates - here we propose a local recalibration procedure by which the atomistic removal rates of a few atoms are modified, thus recovering most features of the experimental fronts in the simulated counterparts. As an application, we evaluate for the first time the ability of the CCA to describe wet etching on Si{110}, focusing on a large collection of wet etched structures including cavities and mesas at different stages of the etching process, obtaining excellent agreement between experiment and simulation.