High performance IGZO/TiO₂ thin film transistors using Y ₂O₃ buffer layers on polycarbonate substrate

In this work, we fabricate IGZO TFT devices on flexible substrate at room temperature. The IGZO/TiO₂ TFT has small subthreshold swing of 0.16 V/dec, but suffers large gate leakage and negative threshold voltage. However, the TiO₂ TFT with Y₂O₃ buffer layers shows improved characteristics including a low threshold voltage of 0.55 V, a small sub-threshold swing of 0.175 V/decade and high field-effect mobility of 43 cm²/Vs. Such good performance can be attributed to the enhanced capacitance density and lowered gate leakage owing to the integration of large band gap Y₂O₃ and low-temperature higher-κ TiO ₂.