An apparatus may include an extraction assembly comprising at least a first extraction aperture and second extraction aperture, the extraction assembly configured to extract at least a first ion beam and second ion beam from a plasma; a target assembly disposed adjacent the extraction assembly and including at least a first target portion comprising a first material and a second target portion comprising a second material, the first target portion and second target portion being disposed to intercept the first ion beam and second ion beam, respectively; and a substrate stage disposed adjacent the target assembly and configured to scan a substrate along a scan axis between a first point and a second point, wherein the first target portion and second target portion are separated from the first point by a first distance and second distance, respectively, the first distance being less than the second distance.