  Growth and roughness of the interface of deposited polymer chains driven by a
field onto an impenetrable adsorbing surface are studied by computer
simulations in (2+1) dimensions. The evolution of the interface width W shows a
crossover from short-time growth described by the exponent beta1 to a long-time
growth with exponent beta2 (>beta1). The saturated width increases, i.e., the
interface roughens, with the molecular weight Lc, but the roughness exponent
alpha (from Ws~L^alpha) becomes negative in contrast to models for particle
deposition; alpha depends on the chain length--a nonuniversal scaling with the
substrate length L. Roughening and deroughening occur as the field E and the
temperature T compete such that Ws=(A+BT)E^-1/2.
