Etchant anisotropy controls the step bunching instability in KOH etching of silicon
STM investigations of vicinal Si(111) surfaces etched in KOH solutions under controlled flow conditions show that step bunching instability is due to inhomogeneities that develop in the etchant as the result of highly step-site-specific etching reactions. Other previously postulated mechanisms for step bunching, including anisotropic surface diffusion, surface strain, and impurity deposition, are conclusively ruled out. The inhomogeneities locally accelerate etching near surface steps. Kinetic Monte Carlo simulations of this process qualitatively reproduce the observed morphologies.
Garcia, Simon; Bao, Hailing; and Hines, Melissa, "Etchant anisotropy controls the step bunching instability in KOH etching of silicon" (2004). Physical Review Letters 93(16): 166102-. Faculty Publications. Paper 65.
Physical Review Letters