Characteristics of La2O3 gate dielectric film with Al implantation using plasma immersion ion implantation

In this work, the effects of aluminum implantation on thin La₂O₃ films grown by e-beam evaporation have been investigated using x-ray photoelectron spectroscopy (XPS), current-voltage (I-V) and capacitance-voltage (C-V) measurements. The small amount of aluminum incorporated (~ 6% near the surface) in the oxide film greatly modifies both material and electrical properties of the dielectric. Reduction in the leakage current (by four orders of magnitude) and the flatband voltage shift are indications of significant removal of the bulk traps from the oxide. The steep transition from the depletion region to the accumulation region in the CV characteristics as well as the XPS results reveal the stoichiometric improvement of the interfacial layer with a reduction in the interface state density. However, the annealing conditions need to be optimized in order to have maximum reduction in oxide traps and leakage current in the Al-PIII La₂O₃ film.