IMPROVEMENT IN THE UNIFORMITY OF RESISTIVITY IN A MAGNETRON-SPUTTERED INDIUM TIN OXIDE FILM BY CONTROLLING THE PLASMA FLUX DISTRIBUTION

The uniformity of resistivity in a magnetron sputtered indium tin oxide (ITO) film has been improved by controlling plasma distribution near the substrate. Plasma distribution was controlled by setting the auxiliary electro magnet around the target. Langmuir probe measurement showed that the plasma density and energy near the substrate were largely changed by the auxiliary magnetic field. ITO film was prepared on a glass substrate which was fixed above the target. The uniformity of film resistivity was improved when the plasma was converged under insufficient oxygen condition. It was also improved when the plasma was diverged under excess oxygen condition. The spatial change of the film resistivity was reduced to within +/-10% over an 18 cm length along the short axis of the target, while it was above +/-45% when the plasma was not controlled. Furthermore, the mean resistivity over the substrate surface was decreased to about three fourths by plasma control.