Negative Bias Temperature Instability in Top-Gated Carbon Nanotube Thin Film Transistors With Y₂O₃ Gate Dielectric

The negative bias temperature instability (NBTI) of the top-gated p-type carbon nanotube (CNT) thin film transistors (TFTs) with yttrium oxide (Y2O3 ) dielectric is investigated under different gate bias, stress and relaxation time for the first time. Positive and fast reversible threshold voltage shift along with significant degradation of subthreshold and trans-conductance are observed. The effects of ambient condition are basically excluded by experimental results, and the NBTI in these CNT devices is believed to be primarily due to the generation of considerable interface traps and border traps near dielectric/CNT interface, highlighting the importance of the interface optimization for CNT TFTs in the future. The hysteresis characteristics during stress and recovery are discussed as well, to further explore the stress-induced-traps properties. All these results may provide a reference for the future study on the gate oxide reliability of CNT TFTs with Y2O3 dielectric.