Indium tin oxide (ITO) film properties and hydrogenated amorphous silicon (a-Si:H) photo diode characteristics are described as a function of the oxygen partial pressure during ITO magnetron sputtering deposition. The photo diode has a Cr/a-Si:H/ITO structure. The a-Si:H and ITO bulk properties along with the a-Si:H/ITO interface properties are important to device performance.
The ITO film deposited at high oxygen partial pressures had a smooth surface and the target did not tarnish during sputtering deposition. Therefore, with respect to stability and reproducibility, ITO deposition at high oxygen partial pressures seems to be quite effective. A high dark photo diode reverse current due to presence Of SiOx (x<2) at the a-Si:H/ITO interface was observed. Portions of the SiOx (x<2) formations were changed to SiO2, by thermal annealing, causing the dark current to decrease remarkably.