Anomalous thermal oxidation of gadolinium thin films deposited on silicon by high pressure sputtering

• Main Authors: Pampillón, María Ángela, Feijoo, Pedro Carlos, Andrés, Enrique San, Lucía, María Luisa, Toledano-Luque, María
• Format: Journal Article
• Language: English
• Published: 29-01-2024
• Subjects: Physics - Applied Physics; Physics - Materials Science
• DOI: 10.48550/arxiv.2402.10925

Microelectronic Engineering 88 (2011) 2991-2996 Thin gadolinium metallic layers were deposited by high-pressure sputtering in
pure Ar atmosphere. Subsequently, in situ thermal oxidation was performed at
temperatures ranging from 150 to 750 $^\circ$C. At an oxidation temperature of
500 $^\circ$C the films show a transition from monoclinic structure to a
mixture of monoclinic and cubic. Regrowth of interfacial SiO$_x$ is observed as
temperature is increased, up to 1.6 nm for 750 $^\circ$C. This temperature
yields the lowest interface trap density, 4e10 eV$^{-1}$ cm$^{-2}$, but the
effective permittivity of the resulting dielectric is only 7.4. The reason of
this low value is found on the oxidation mechanism, which yields a surface with
located bumps. These bumps increase the average thickness, thus reducing the
capacitance and therefore the calculated permittivity.