Atomic layer deposition and characterization of HfO2 films on noble metal film substrates

HfO2 films were grown by atomic layer deposition from HfCl4 and H2O on atomic layer deposited 40-70 nm thick platinum, iridium, and ruthenium films in the temperature range 200-600 degrees C. The phase formed in the 30-50 nm thick HfO2 films was monoclinic HfO2 dominating over amorphous material without noticeable contribution from metastable crystallographic polymorphs. The metal-dielectric-metal capacitor structures formed after evaporating Al gate electrodes demonstrated effective permittivity values in the range 11-16 and breakdown fields reaching 5 MV/cm. Iridium electrode films showed the highest stability in terms of reliability and reproducibility of dielectric characteristics. (c) 2005 The Electrochemical Society. All rights reserved.