Extremely bias stress stable enhancement mode sol–gel-processed SnO2 thin-film transistors with Y2O3 passivation layers

Abstract Herein, a new combination of high-performance and bias-stress-stable SnO2 thin-film transistors (TFTs) with Y2O3 passivation layers is introduced. The Y2O3 layers on SnO2 semiconductors function suitably as passivation layers to minimize H2O adsorption and to avoid free carrier trapping by creating physical gaps that are larger than the characteristic diffusion length. Yttrium is observed to partially diffuse into SnO2, suppressing the formation of oxygen vacancies in the SnO2 semiconductor because of its low electronegativity and standard electrode potential. The SnO2 TFTs with Y2O3 passivation layers exhibit a mobility of 5.7 ± 0.3 cm2/Vs, subthreshold swing of 1.1 ± 0.2 V/decade, threshold voltage (VTH) of + 6.8 ± 0.4 V, and on/off current ratio of 6.1 (±0.3) × 107. The fabricated sol–gel-processed SnO2 TFTs with Y2O3 passivation layers revealed remarkable negative and positive bias stress stabilities without hysteresis and consistently delivered high performance with enhancement mode operations. Owing to this high performance, the SnO2/Y2O3 combination reported herein has potential as a commercial-product-level TFT for next-generation displays.