Influence of Post-Annealing on Electrical Characteristics of Thin-Film Transistors with Atomic-Layer-Deposited ZnO-Channel/Al₂O₃-Dielectric

【摘要】 High-performance thin-film transistors（TFTs） with a low thermal budget are highly desired for flexible electronic applications.In this work,the TFTs with atomic layer deposited ZnO-channel/Al₂O₃-dielectric are fabricated under the maximum process temperature of 200℃.First,we investigate the effect of post-annealing environment such as N₂,H₂-N₂（4%） and O₂ on the device performance,revealing that O₂ annealing can greatly enhance the device performance.Further,we compare the influences of annealing temperature and time on the device performance.It is found that long annealing at 200℃ is equivalent to and even outperforms short annealing at 300℃.Excellent electrical characteristics of the TFTs are demonstrated after O₂ annealing at 200℃ for 35 min,including a low off-current of 2.3 × 10^-13 A,a small sub-threshold swing of 245mV/dec,a large on/off current ratio of 7.6×10⁸,and a high electron effective mobility of 22.1cm²/V·s.Under negative gate bias stress at — 10 V,the above devices show better electrical stabilities than those post-annealed at 300℃.Thus the fabricated high-performance ZnO TFT with a low thermal budget is very promising for flexible electronic applications.更多还原

【Abstract】 High-performance thin-film transistors（TFTs） with a low thermal budget are highly desired for flexible electronic applications.In this work,the TFTs with atomic layer deposited ZnO-channel/Al₂O₃-dielectric are fabricated under the maximum process temperature of 200℃.First,we investigate the effect of post-annealing environment such as N₂,H₂-N₂（4%） and O₂ on the device performance,revealing that O₂ annealing can greatly enhance the device performance.Further,we compare the influences of annealing temperature and time on the device performance.It is found that long annealing at 200℃ is equivalent to and even outperforms short annealing at 300℃.Excellent electrical characteristics of the TFTs are demonstrated after O₂ annealing at 200℃ for 35 min,including a low off-current of 2.3 × 10^-13 A,a small sub-threshold swing of 245mV/dec,a large on/off current ratio of 7.6×10⁸,and a high electron effective mobility of 22.1cm²/V·s.Under negative gate bias stress at — 10 V,the above devices show better electrical stabilities than those post-annealed at 300℃.Thus the fabricated high-performance ZnO TFT with a low thermal budget is very promising for flexible electronic applications.更多还原