Simple chemical solution deposition of Al2O3 dielectric layers for low-cost fabrication of transparent electronic devices

• Published in: Journal of materials science. Materials in electronics 2024-06, Vol.35 (16), p.1038, Article 1038
• Main Authors: Borges-Doren, I., Suárez-Campos, G., Cabrera-German, D., Ruiz-Molina, M. A., Ramos-Carrazco, A., Berman-Mendoza, D., Sotelo-Lerma, M.
• Format: Article
• Language: English
• Subjects: Aluminum oxide; Channel morphology; Characterization and Evaluation of Materials; Chemistry and Materials Science; Deposition; Dielectrics; Gold; Leakage current; Low cost; Materials Science; Morphology; Optical and Electronic Materials; Semiconductor devices; Substrates; Synthesis; Thin film transistors; Threshold voltage; Zinc oxide; Zinc oxides
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-024-12787-y

This study investigates the influence of chemically synthesized Al 2 O 3 dielectric layers on the performance of both metal–insulator - metal (MIM) capacitors (FTO/Al 2 O 3 /Au) and transparent thin film transistors (TTFTs) (FTO/Al 2 O 3 /ZnO/Au). Using two distinct formulations, a detail comparison based on varying precursors concentrations and the deposition time is presented. Scanning electron microscopy shows a nanopore morphology in the Al 2 O 3 dielectric layers. Electrical characterizations for MIM devices yielded leakage currents around 6 × 10 - 4 A ∙ cm 2 and capacitance values in the 107–77 nF/cm 2 range. For TTFTs, drain current vs drain-source voltage ( I D -V DS ) ( ∼ 1 - 8.5 μ A ) and drain current vs gate voltage ( I D -V GS ) (on/off ratio 2.4 × 10 2 ) were measured with chemically synthesized ZnO. Using a zinc oxide semiconductor as the active channel, the threshold voltage ( V on/off  =  ~ 36 V) and mobility ( µ  = 1.23 cm 2 /Vs) was obtained. The application of Al 2 O 3 as the dielectric gate, which acts as a substrate for ZnO deposition during device fabrication, induced a ZnO dendritic-like surface morphology, influencing channel conduction and exhibiting distinctive electrical behaviors corresponding to each formulation. Beyond the demonstrated capabilities of Al 2 O 3 in these devices, this material demonstrates advantages for highly transparent and effective low-cost device fabrication.