Sputtering Effects during 3D-Imaging of Indium-Tin-Oxide Sputtering Targets

Thin layers of indium tin oxide are applied as electrical contacts in flat displays since they are conductive and optically transparent [I]. Targets are coated with IT0 by reactive magnetron sputtering. A partially reduced ITO-sputtering target is eroded by a Arlo plasma. Sputtered In and Sn atoms are oxidized within the plasma and redeposited on the substrate. During the sputtering process small nodules with diameters up to IOOwm grow on the surface of the sputtering target. These nodules cause small arcs that estabilize the sputtering process. In addition small particles are eroded from he surface and contaminate the substrate. is well known that inhomogeneously distributed impurities with a sputtering yield than the matrix may cause such nodule growth [2]. this study we have used secondary ion mass spectrometry to ermine: (1) whether or not such inhomogeneously distributed impurities an be found in the ITO-sputtering targets, (2) the compositions of any mpurities found, and (3) the influence impurities have on the sputtering ehavior. SIMS is one of the few analytical methods being capable of images of elemental distributions [3] and is, therefore, ted for this type of investigation. In addition, the influence of puttering behavior should be directly seen in the count rates