Effects of Source/Drain Electrodes on Thermal Stability of IGZO FETs in the Oxygen-Deficient Environment

This work presents the first comprehensive investigation on the thermal stability of indium-gallium-zinc-oxide (IGZO) field-effect transistors (FETs) with sub-l0 nm channel and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">HfO₂</tex> dielectric in the oxygen-deficient environment for temperatures up to <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">450 \ ∘C</tex> . Surprisingly, we found that using Ni as sourceldrain (SID) electrodes helps to reduce the negative threshold voltage <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">(Vₜₕ)</tex> shift after high-temperature annealing, significantly enhancing the thermal stability of IGZO FETs.