PLD DEPOSITED Al2O3 THIN FILMS FOR TRANSPARENT ELECTRONICS

Alumina (Al2O3) films of 800 nm thicknesses were obtained by pulsed laser deposition method. The chemical composition and the morphology of as grown films were investigated by Energy Dispersive X-ray spectroscopy (EDX), Scanning Electron Microscopy, Atomic Force Microscopy and optical transmittance spectroscopy (OTS) techniques. EDX results show a stoichiometric transfer between target and substrates and the bandgap energy and refractive index obtained by OTS were found to be in good agreement with the bulk values. Dielectric characterizations of Al2O3 films were performed, in a sandwich structure using titanium (Ti) as back electrodes (100 nm) and aluminum (Al) as top electrodes (100 nm). The temperature dependence of permittivity and dielectric losses of Ti/Al2O3/Al capacitors have been measured between 123 - 423 K at selected frequencies in the 42 Hz - 5 MHz ranges. The dielectric constant of Al2O3 determined from capacitance measurements was found to be around 8.3 at 273 K. The temperature and frequency dependence of both the permittivity and dielectric loss values are weak in the investigated temperature and frequencies ranges.