We introduce a model for epitaxial phenomena based on the motion of island
boundaries, which is described by the level-set method. Our model treats th
e growing film as a continuum in the lateral direction, but retains atomist
ic discreteness in the growth direction. An example of such an "island dyna
mics" model using the level-set method is presented and compared with the c
orresponding rate equation description. Extensions of our methodology to mo
re general settings are then discussed. [S1063-651X(98)50212-7].