Preparation and characterization of SnO films via reactive sputtering for ambipolar thin-film transistor applications

Abstract

SnO films are prepared by reactive magnetron sputtering under various O2 partial pressures along with post-annealing in air. The results indicate that the O2 partial pressure during reactive sputtering process not only influences the composition of the SnO film but also its texture. For the SnO film deposited under 10% O2 partial pressure, its direct bandgap increases from 2.49 to 2.64 eV with elevating the post-annealing temperature from 250 °C to 400 °C. The above SnO-based channel thin-film transistors (TFTs) exhibit a typical ambipolar feature after post-annealing at ≥250 °C in air. For the TFTs annealed at 300 °C for 30 min, the extracted hole and electron field-effect mobility is 1.48 cm2V−1s−1 and 0.21 cm2V−1s−1, respectively. The performance of both p- and n-type TFTs could be further improved by optimizing fabrication process and post-annealing conditions because of a trade-off between hole and electron mobility.