Electrical performance enhancement of p-type tin oxide channel thin film transistor using aluminum doping

Abstract A narrow process window for the fabrication of p-type semiconductors is one of the major challenges in implementing tin oxide (SnO x ) in thin film transistor applications. The SnO x lattice was doped with Al to widen the process window and enhance the p-type channel thin film transistor performance with co-sputtering process. A change in the growth orientation direction with the presence of Al in SnO x thin films was observed in the grazing-incidence X-ray diffraction data. The changes in the oxidation states of Sn ions were determines by X-ray photoelectron spectroscopy. With increasing Al concentration, the ratio of Sn 4 + in the Sn peaks decreases indicating that the SnO x film has improved p-type properties. These changes led to an improvement of the electrical properties such as output characteristic, field effect mobility, subthreshold swing, and positive shift of threshold voltage.