Embodiments of the invention include sulfur alloyed InGaZnO (IGZOS) thin film transistors (TFTs) and methods of making such devices. In one embodiment, the IGZOS TFT may include a substrate and a gate electrode formed over the substrate. A gate dielectric layer may be formed over the gate electrode. An IGZOS film may be formed over a surface of the gate dielectric. Additionally, embodiments of the invention include a source region and a drain region formed in contact with the IGZOS film. An opening between the source region and the drain region may define a channel region in the IGZOS film. Embodiments of the invention are able to form a p-type IGZO TFT by increasing the valence band of the IGZO material in order to eliminate the presence of trap states in the band gap. The valance band may be raised by doping the IGZO material with sulfur.
