LAUSR

Abstract We demonstrate patterned Al2O3 formation by post-plasma oxidation of a thin layer of aluminium (Al) film deposited by electron beam evaporator in area selective regions. The oxide quality is observed to further improve by annealing in O2 and N2 environment. Schottky and metal-insulator-semiconductor diodes are also fabricated to characterize its electrical behaviour. The thickness and high quality of the oxide formed is confirmed from Transmission Electron Microscope (TEM) and X-Ray Photoelectron Spectroscopy (XPS) analysis. The O2 and N2 annealed samples show Oxygen to Aluminium atomic ratio of ~1.5 confirming near-ideal stoichiometry. The energy band-gap (Eg) of the Plasma-Oxide, O2-Annealed and N2-Annealed estimated from energy loss spectra of O1s are found to be 5.0, 5.5 and 6.8 eV, respectively. The valance band off-set for the corresponding oxides as estimated from low energy spectra analysis are found to be 0.8, 0.7 and 0.8 eV, respectively. The electrical characteristics also confirm improvement over the control device. The ION/IOFF ratios are observed to be 106, 1010 and 106 for the Plasma Oxide, O2 Annealed and N2 Annealed oxides, respectively, as compared to 103 for the Control sample. The dielectric constants (eox) for the corresponding oxides as determined from the C V characteristics are found to be 5.3, 8.5 and 8.7, respectively.