High-Performance Amorphous InGaZnO Thin-Film Transistors With HfO2/Lu2O3/HfO2 Sandwich Gate Dielectrics

In this brief, a high-performance amorphous InGaZnO ( $\alpha $ -IGZO) thin-film transistor (TFT) with a HfO2/Lu2O3/HfO2 (HLH) sandwich gate dielectric is demonstrated for the first time. Compared with the Lu2O3 dielectric, the $\alpha $ -IGZO TFT device using an HLH sandwich gate dielectric exhibited a low threshold voltage of 0.43 V, a high field-effect mobility of 17.2 cm $^{2}$ /Vs, a small subthreshold swing of 104 mV/decade, and a high $I_{\rm {ON}} / I_{\rm {OFF}}$ current ratio of $3.08\times 10^{7}$ , presumably because of the reduction of surface roughness at the dielectric–channel interface. Furthermore, the reliability of voltage stress can be improved using an HLH sandwich dielectric structure.