Hydrogen-Defect Termination in SnO for p-Channel TFTs

Developing high-performance p-channel oxide thin-film transistor (TFT) and practical oxide TFT-based complementary circuits is the most persistent challenge for oxide electronics and a major hurdle for future oxide device technology to overcome. Tin monoxide, SnO, is known as one of the promising candidates for an active layer of p-channel oxide TFT, owing to its reasonably high hole carrier mobility (over 1 cm2 V–1 s–1) and low-cost processability. However, high-density subgap defect spoils its high potential for electronic devices and hinders the development of SnO-based high-performance p-channel oxide TFTs. Here, we present hydrogen-defect termination for SnO to improve the device performance of p-channel oxide TFT. Thermal annealing in hydrogen ambient using a pure NH3 at 360 °C offers good TFT characteristics with the saturation mobilities of ∼1.4–1.8 cm2 V–1 s–1 and an on-to-off current ratio of ∼105 because of the hydrogen termination of the subgap hole trap originating from the oxygen vacancy. A complementary inverter comprising p-channel SnO and n-channel a-IGZO TFTs was demonstrated with a maximum voltage gain of ∼50. This present achievement is an important step toward building low-cost next-generation oxide electronics.