Study of the effect of the oxygen partial pressure on the properties of rf reactive magnetron sputtered tin-doped indium oxide films

The influence of the oxygen partial pressure on the properties of indium tin oxide films deposited by rf reactive magnetron sputtering has been studied. The oxygen partial pressure was varied from 3.2 x 10(-4) to 1.0 x 10(-3) mbar. It has been found that the 4 x 10(-4) mbar of oxygen partial pressure is a critical point. When the oxygen partial pressure is lower than 4 x 10(-4) mbar, the deposition rate of the films is high; the films have low transmittance and electrical resistivity; the X-ray diffraction shows that the films have a random orientation and the images of the scanning electron microscopy show that the films surface are smooth without structure. When the pressure is higher than 4 x 10(-4) mbar, the deposition rate is low and does not change as the oxygen partial pressure is further increased; the transmittance and the electrical resistivity are both high; the films show the preferred orientation along the (440) direction; the films surface show a clear structure and as the pressure is increased further, the films become porous. Considering both the factor of transmittance and resistivity, the optimum oxygen partial pressure will be 3.6 x 10(-4) mbar. The films prepared at this pressure have 80% transmittance and 9 x 10(-4) Omega cm resistivity. (C) 1997 Elsevier Science B.V.