Abstract: A longitudinally extending cross-flow liner within a longitudinally extending cylindrical reaction vessel cooperates with at least one longitudinally extending gas injector within the cross-flow liner to provide transversely flowing gas across the surfaces of vertically oriented semiconductor wafers in such a way as to substantially eliminate both depletion phenomenon and downstream wafer pollution caused from particulates, unreacted reactant gas, and other contaminants and to provide uniformly coated wafers in a batch and repeatability batch to batch.