Hybrid Nanostructures Based of Ta2O5-PMMA for Electronic Applications

Résumé

The scientific interest on hybrid materials is mainly related to understanding the types of interactions between inorganic and organic component and the effect of these interactions on the properties of the new material formed. Hybrid nanostructured materials and especially dielectrics are used for electronics (for gate layer) and especially those applicable in structure of different types of thin film transistors (TFTs).
In this paper is presented the research on thin film hybrid materials based on tantalum oxide (Ta₂O₅) starting with inorganic precursor - tantalum ethoxide and polymethylmethacrylate (PMMA). The chemical method sol -gel involves the precursor-tantalum ethoxide which is hydrolysed and functionalized (with special siloxane compound), and the organic methyl methacrylate monomer. The chemical reactions take place at low temperature below 160 ^oC. The sol is deposited as thin films by spin-coating to analyse intensity-voltage (I-V) and capacitance-voltage curves (C-V) to determine the electric properties. Metal-Insulator-Metal (MIM) structures were made-up for electric characterisation. The value of leakage currents was between 10^-10 - 10^-7 A at ± 40 V. The hybrid films were analysed by scanning electron microscopy (SEM) for thickness and morphology and for thermal stability the sol was investigated by TG and DSC.
The dielectric permittivity ranges between 3.5 and 4 at 1 MHz, depending on the tantalum alkoxide: MMA molar ratio, showing good behaviour for gate layer in future TFTs.