A model for surface growth with some of the features of molecular-beam
epitaxy is proposed and investigated. Particles are deposited randoml
y on a one-dimensional substrate and the surface relaxes through diffu
sion processes, which obey detailed balance. The model undergoes a pha
se transition from a rough phase to a grooved phase. Both phases disPl
ay scaling in space and time, with equal exponents. We also propose a
Langevin equation which should describe this growth process and show t
hat this equation contains an infinite number of relevant terms.