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 (<inline-formula> <tex-math notation="LaTeX">${a}$ </tex-math></inline-formula>-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, <inline-formula> <tex-math notation="LaTeX">${a}$ </tex-math></inline-formula>-In<inline-formula> <tex-math notation="LaTeX">$_{{0.60}}$ </tex-math></inline-formula>Ga<inline-formula> <tex-math notation="LaTeX">$_{{0.14}}$ </tex-math></inline-formula>Zn<inline-formula> <tex-math notation="LaTeX">$_{{0.20}}$ </tex-math></inline-formula>Sn<inline-formula> <tex-math notation="LaTeX">$_{{0.06}}\text{O}$ </tex-math></inline-formula> 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 (<inline-formula> <tex-math notation="LaTeX">${V} _{\text {TH}}$ </tex-math></inline-formula>) of −0.40 V, and an <inline-formula> <tex-math notation="LaTeX">${I} _{\text {ON/OFF}}$ </tex-math></inline-formula> ratio of <inline-formula> <tex-math notation="LaTeX">$3\times 10^{{8}}$ </tex-math></inline-formula>. Furthermore, the TFTs demonstrated excellent bias temperature stress (BTS) reliability, with minimal variations in <inline-formula> <tex-math notation="LaTeX">${V} _{\text {TH}}$ </tex-math></inline-formula> (<inline-formula> <tex-math notation="LaTeX">$\Delta {V}_{\text {TH}}$ </tex-math></inline-formula>) 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<inline-formula> <tex-math notation="LaTeX">$^{\text {3+}}$ </tex-math></inline-formula> and Sn<inline-formula> <tex-math notation="LaTeX">$^{\text {4+}}$ </tex-math></inline-formula> and the beneficial hydrogen-doping effect near Sn cations.