Underetching from simple stochastic etching kinetics
Jens Christian Claussen, J\"urgen Carstensen
The morphological richness of electrochemical semiconductor etching is not sufficiently counterparted yet by theoretical modeling.
This paper investigates a minimal version of the Current-Burst model with Aging of F\"oll and Carstensen and demonstrates for a
restricted geometry that the Aging concept is essential for underetching, or cavity generation.
If the influence of Aging is neglected, the dynamics reduces to a Random Etching Model similar to the Random Deposition model.
This computer {\sl gedanken experiment} demonstrates that the stochastic dynamics with ageing-dependent kinetic reaction probabilities
accounts for the different etching morphologies compared to those obtained in surface roughening and related systems.