Optimization of in situ plasma oxidation of metallic gadolinium thin films deposited by high pressure sputtering on silicon

Abstract

Gadolinium oxide thin films were deposited on silicon by a two-step process: high pressure sputtering from a metallic gadolinium target followed by an in situ plasma oxidation. Several plasma conditions for metal deposition and oxidation were studied in order to minimize the growth of a SiOx layer at the interface between the high permittivity dielectric and the silicon substrate and to avoid substrate damage. Plasma emission was studied with glow discharge optical spectroscopy. The films were structurally characterized by Fourier transform infrared spectroscopy. Metal-insulator-semiconductor capacitors were fabricated with two different top metals (titanium and platinum) to analyze the influence of deposition conditions and the metal choice. Pt gated devices showed an interfacial SiOx regrowth after a forming gas annealing, while Ti gates scavenge the interface layer.