Phenomenological modeling of low-bias sulfur hexafluoride plasma etching of silicon

•Low-bias plasma etching of Si using SF6 is a near-isotropic alternative to wet etching.•Precise topography simulation of the final etched geometries is difficult.•Our phenomenological model can replicate multiple etched geometries with a single parameter set.•We link the main phenomenological parameter, the average effective sticking coefficient β, to a measurable degree of isotropy I.•Using our proposed empirical relationship between β and I, isotropic etch recipe development can be fine-tuned.