  The dewetting dynamics of an ultrathin film is studied in the presence of
evaporation - or reaction - of adatoms on the substrate. KMC simulations are in
good agreement with an analytical model with diffusion, rim facetting, and
substrate sublimation. As sublimation is increased, we find a transition from
the usual dewetting regime where the front slows down with time, to a
sublimation-controlled regime where the front velocity is approximately
constant. The rim width exhibits an unexpected non-monotonous behavior, with a
maximum in time.
