Achieving High Field-Effect Mobility Exceeding 90 cm²/Vs in a-IGZTO Transistors With Excellent Reliability

In this letter, amorphous indium-gallium-zinc-tin oxide ( ${a}$ -IGZTO) thin-film transistors (TFTs) were characterized with a bottom gate structure, where a single target with three cation composition ratios were used to deposit the a-IGZTO channel layer. Remarkably, ${a}$ -In $_{{0.60}}$ Ga $_{{0.14}}$ Zn $_{{0.20}}$ Sn $_{{0.06}}\text{O}$ TFTs exhibited exceptional performance, featuring a significantly high field-effect mobility of 90.2 cm2/Vs, a low subthreshold swing of 0.10 V/decade, a threshold voltage ( ${V} _{\text {TH}}$ ) of −0.40 V, and an ${I} _{\text {ON/OFF}}$ ratio of $3\times 10^{{8}}$ . Furthermore, the TFTs demonstrated excellent bias temperature stress (BTS) reliability, with minimal variations in ${V} _{\text {TH}}$ ( $\Delta {V}_{\text {TH}}$ ) less than ±0.08 V under negative and positive bias temperature stress at 60 °C for 1 hour. The impressive performance and reliability observed in these TFTs can be attributed to the synergistic percolation of In $^{\text {3+}}$ and Sn $^{\text {4+}}$ and the beneficial hydrogen-doping effect near Sn cations.