Hf–O–N and HfO 2 barrier layers for Hf–Ti–O gate dielectric thin films

Abstract

Hf–O–N and HfO 2 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)-HfTiO 4 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 HfO 2 barrier layer. Leakage current densities lower than 5 × 10 A/cm 2 were achieved with both barrier layers at a sub 20 Å equivalent oxide thickness.