Hf–O–N and HfO2 barrier layers for Hf–Ti–O gate dielectric thin films

Abstract: Hf–O–N and HfO2 thin films were evaluated as barrier layers for Hf–Ti–O metal oxide semiconductor capacitor structures. The films were processed by sequential pulsed laser deposition at 300°C and ultra-violet ozone oxidation process at 500°C. The as-deposited Hf–Ti–O films were polycrystalline in nature after oxidation at 500°C and a fully crystallized (o)-HfTiO4 phase was formed upon high temperature annealing at 900°C. The Hf–Ti–O films deposited on Hf–O–N barrier layer exhibited a higher dielectric constant than the films deposited on the HfO2 barrier layer. Leakage current densities lower than 5×10A/cm2 were achieved with both barrier layers at a sub 20Å equivalent oxide thickness. [Copyright &y& Elsevier]