Susceptibility of SiO 2 , ZrO 2 , and HfO 2 dielectrics to moisture contamination

Moisture contamination of HfO 2 and ZrO 2 ultrathin dielectric films, deposited by atomic layer chemical vapor deposition (ALCVD™), is investigated and compared to that of native SiO 2 . Results show that HfO 2 and ZrO 2 surfaces adsorb higher amounts of moisture and bind moisture more strongly than SiO 2 surfaces. A multilayer model is developed to represent the dynamics of moisture interaction with these three oxides. Using this model, the fundamental kinetic parameters are determined. The adsorption rate constants are of the same order of magnitude for all three surfaces. However, the desorption rate constants for ZrO 2 and HfO 2 are almost three orders of magnitude lower than that for SiO 2 . Activation energies for desorption of water molecules from the first two layers are 33, 27, and 19 kJ/mol, for ZrO 2 , HfO 2 , and SiO 2 , respectively. Results obtained in this study suggest that the HfO 2 and ZrO 2 , as the new dielectric materials, are more prone to moisture contamination than SiO 2 . © 2004 American Institute of Chemical Engineers AIChE J, 50: 1881–1888, 2004