Low-Temperature Growth of Indium Oxide Thin Film by Plasma-Enhanced Atomic Layer Deposition Using Liquid Dimethyl(N-ethoxy-2,2-dimethylpropanamido)indium for High-Mobility Thin Film Transistor Application

Low-temperature growth of In2O3 films was demonstrated at 70–250 °C by plasma-enhanced atomic layer deposition (PEALD) using a newly synthesized liquid indium precursor, dimethyl(N-ethoxy-2,2-dimethylcarboxylicpropanamide)indium (Me2In(EDPA)), and O2 plasma for application to high-mobility thin film transistors. Self-limiting In2O3 PEALD growth was observed with a saturated growth rate of approximately 0.053 nm/cycle in an ALD temperature window of 90–180 °C. As-deposited In2O3 films showed negligible residual impurity, film densities as high as 6.64–7.16 g/cm3, smooth surface morphology with a root-mean-square (RMS) roughness of approximately 0.2 nm, and semiconducting level carrier concentrations of 1017–1018 cm–3. Ultrathin In2O3 channel-based thin film transistors (TFTs) were fabricated in a coplanar bottom gate structure, and their electrical performances were evaluated. Because of the excellent quality of In2O3 films, superior electronic switching performances were achieved with high field effect mo...