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Graphical abstract Highlights • Low temperature processing of hybrid dielectric gate layers by sol-gel. • Al 2 O 3 -GPTMS-PMMA hybrid films for applications as dielectric gate in TFT. • ZnO-based thin-film transistors with high Ion/Ioff current ratio. Abstract In this work we evaluate the synthesis of inorganic-organic Al 2 O 3 -GPTMS-PMMA hybrid films using a low temperature sol-gel process and their use as gate dielectric for thin film transistors (TFTs). The hybrid films were deposited by dip coating process and then annealed at 150 °C in air. The analysis of the hybrid films was performed by UV–VIS spectroscopy, FTIR, AFM, SEM, C-V and I-V measurements. The optical transparency above 85% in the visible range and homogeneity of the hybrid films support the proper link between inorganic and organic phases with strong bonds. At microscopic level, the hybrid films have uniform surface roughness lower than 1 nm. The C-V and I-V measurements performed on MIM structures showed leakage current density in the order of 10−7 A/cm2 at 104 kV/cm electric field. Capacitance and dielectric constant measured at 1 kHz were 20.4 pF and of 6.2, respectively. TFTs were fabricated using bottom gate and aluminium top contacts to obtain mobilities of 4.5 cm2/Vs, threshold voltage of 0.7 V and I on /I off ratio of 107, while mantaining operating voltage under 8 V. [ABSTRACT FROM AUTHOR]

Abstract In this work, we developed a novel inorganic-organic hybrid gate dielectric by combining zirconium and hafnium components to form zirconium hafnium oxide strongly linked with polymethyl methacrylate (ZrHfO 2 -PMMA) and deposited at low temperature (200 °C) by sol-gel method. The obtained 108 nm thick, high-quality hybrid gate dielectric showed an exceptionally low surface roughness (0.9-nm), a low leakage current density (7.7 × 10−6 A/cm2) and reasonable dielectric properties such as gate capacitance along with dielectric constant (77 nF/cm2 & 9.4 @1 kHz) respectively. To examine the ZrHfO 2 -PMMA hybrid dielectric electrical properties we constructed thin-film transistors (TFTs) with room temperature r.f sputtered n-type metal oxide semiconductors, a-IGZO and ZnO, as active channels. The bottom gate fabricated a-IGZO TFTs driving at as low as below 6 V, with extracted field effect mobility of 2.45 cm2/V. s, a low threshold voltage of 1.2 V with large ON/OFF current ratio 107 respectively. On the other hand, for comparison we employed ZnO TFTs by applying same hybrid dielectric system, the obtained parameters of bottom gate ZnO TFTs were good field effect saturation mobility of 12.8 cm2/V. s, threshold voltage of 1.8 V and ON/OFF current ratio of 103. Highlights • Novel ZrHfO 2 -PMMA hybrid gate dielectric layer by sol-gel process at low temperature (200 °C). • Cross-linked, homogeneous and highly transparent hybrid dielectric layers with amorphous nature and very low surface roughness. • Hybrid dielectric layers with low leakage current density (10−6 A/cm2), good capacitance (77 nF/cm2) and high dielectric constant (9.4). • IGZO-based TFTs with hybrid dielectric gate with mobility of 2.45 cm2/Vs, low threshold voltage of 1.2 V and large current ON/OFF ratio of 107. [ABSTRACT FROM AUTHOR]