Studies on Electrical Properties of Hybrid Polymeric Gate Dielectrics for Field Effect Transistors

The miniaturization of field effect transistor (FET) has been reached to the saturation due to further decrease in the thickness of SiO2 gate dielectrics. The polymeric gate dielectrics have been attracted considerable attention to the development of organic field effect transistors onto indiumtin-oxide (ITO) substrates. The polymeric gate dielectrics such aspolyvinyl alcohol (PVA), Polymethylmethacrylate (PMMA), Poly-4-vinylphenol (PVP) have low dielectric constants; however by introducing inorganic oxides, viz TiO2, ZnO, HfO etc, the dielectric constant can be increased. The PVA cross linked with ammonium dichromate (PVAad) was spun onto ITO substrates. TiO2 nanoparticles were incorporated into PVAad solution and the resultant films were irradiated by ultraviolet irradiation for different time durations. PVA/TiO2 nanoparticles (NPs) hybrid composite thin films were prepared using sol-gel spin coating technique. TiO2 NPs were prepared using different surfactants such as acetic acid (AA), oleic acid (OA), oley amine (OM), and a mixture of OA/OM by solvothermal route. MIS (ITO/(PVA + TiO2)/Au) structure was fabricated by evaporatoring Au electrode. The electrical measurements, capacitance-voltage (C-V) measurements were performed using two probe measurement setup. We found that the dielectric constant of PVA + TiO2 filmwas systematically tailored from(2-3.4) for PVA to approximately (5.6-6.9) for PVA + TiO2 nanoparticles.