Role of Structure and Composition on the Performances of P-Type Tin Oxide Thin-Film Transistors Processed at Low-Temperatures.

This work reports on the role of structure and composition on the determination of the performances of p-type SnO TFTs with a bottom gate configuration deposited by rf magnetron sputtering at room temperature, followed by a post-annealed step up to 200 °C at different oxygen partial pressures (O) between 0% and 20% but where the p-type conduction was only observed between in a narrow window, from 2.8% to 3.8%. The role of structure and composition were evaluated by XRD and Mössbauer spectroscopic studies that allows to identify the best phases/compositions and thicknesses (around 12 nm) to be used to produce p-type TFTs with saturation mobility of 4.6 cm² V s and on-off ratio above 7 × 10⁴, operating at the enhancement mode with a saturation voltage of -10 V. Moreover, a brief overview is also presented concerning the present state of the existing developments in processing SnO TFTs with different methods and using different device configurations.