Deposition of TaN Films by RF Sputtering and Their Barrier Properties in Cu/TaN/Dielectrics/Si MIS Structures

Abstract

The electrical resistivity and the barrier property of Tantalum nitride (TaN) thin films were systematically investigated as a function of annealing temperature using two different types of MIS structures of TaN/SiO₂/Si and Cu/TaN/dielectric/Si(100), where either the thermally grown SiO₂ (th-SiO₂) or spin-on dielectric (SOD) hydrogen silsesquioxane (HSQ) films was used as a dielectric layer. We observed that the resistivity of TaN thin films before Cu deposition became lower with the growth of TaN(200) as compared with the growth of TaN(111) and TaN(220). Cu diffusion barrier properties of MIS diodes with TaN films were improved up to 500°C for both dielectric films due presumably to the decrease in sputter damage of dielectric films by annealing, while those without TaN thin films were degraded due to the diffusion of Cu into the dielectric films. The oxygen desorption from dielectric films and the oxidation of TaN films due to the reverse-sputtering of dielectric films during the sputtering of Ta in N₂ is possible model of sputter damage. [DOI: 10.1380/ejssnt.2012.107]