Achieving High Field-Effect Mobility Exceeding 90 cm<sup>2</sup>/Vs in <i>a</i>-IGZTO Transistors With Excellent Reliability
Bang Ju Park, Sang Won Chung, Min Jae Kim, Heung Jo Lee, Jae Hoon Bae, Sung Chun Kang, Jae Kyeong Jeong
Abstract
In this letter, amorphous indium-gallium-zinc-tin oxide ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <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 xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${a}$ </tex-math></inline-formula> -In <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{{0.60}}$ </tex-math></inline-formula> Ga <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{{0.14}}$ </tex-math></inline-formula> Zn <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{{0.20}}$ </tex-math></inline-formula> Sn <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <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 xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V} _{\text {TH}}$ </tex-math></inline-formula> ) of −0.40 V, and an <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I} _{\text {ON/OFF}}$ </tex-math></inline-formula> ratio of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <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 xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V} _{\text {TH}}$ </tex-math></inline-formula> ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <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 xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{\text {3+}}$ </tex-math></inline-formula> and Sn <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{\text {4+}}$ </tex-math></inline-formula> and the beneficial hydrogen-doping effect near Sn cations.