  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.
