Rapid thermal processed thin films of reactively sputtered Ta₂O₅

Abstract

Rapid thermal processed thin films of reactively sputtered tantalum pentoxide Ta₂O₅ thin films have been deposited on silicon and platinum coated silicon substrates by reactive magnetron sputtering. The as-deposited films were amorphous and showed good electrical properties in terms of a dielectric permittivity of about 24 and leakage current density of 9 × 10^-8 A cm^-2. A rapid thermal annealing process at temperatures above 700 ° C crystallized the films, increased the dielectric relative permittivity, and decreased the leakage current. The dielectric constant for a film rapidly annealed at 850 ° C increased to 45 and its leakage current density lowered to 2 × 10^-8 A cm^-2. The dielectric measurements in the MIS configuration showed that Ta₂O₅ might be used as a dielectric material instead of SiO₂ or Si₃N₄ for integrated devices. The current voltage characteristics observed at low and high fields suggested different conduction mechanisms.