Effect of Post-Treatment Temperature on TiN Barrier Properties during a Two-Step Annealing for ( Ba , Sr ) TiO3 Dielectric Film

Abstract

The effect of various post-treatment temperatures on the oxidation behavior of a TiN diffusion barrier was investigated as a function of a two-step annealing. Both the Ru-O/Ru/TiN/poly-Si/Si and BST/Ru-O/Ru/TiN/poly-Si/Si structures retained their structure without an increase in resistivity even after annealing at 550°C and the two-step annealing, while for both the and structures, the degradation is started after annealing at 400°C. In the latter case, the film was a porous amorphous structure, no formation of a thin layer, and many voids, resulting from free diffusion of oxygen and oxidation of TiN diffusion barrier. Meanwhile, in the former case, the role of the thin oxidized layer formed at the surface of Ru film after annealing at 400°C leads to the strongly stuffed along the grain boundaries as well as matrix and the formation of chemically strong bonds with Ru-O. At 400°C and after the two-step annealing, the conductive phase is formed at the surface of Ru film, giving rise to oxygen sink layer. In addition, the BST/Ru-O layer leads to confusion of the oxygen indiffusion through the BST/Ru-O layer during annealing at 420°C for 5 min in oxidizing ambient, followed by a suppression of oxygen indiffusion and an improvement of TiN barrier properties. Therefore, both the Ru-O/Ru/TiN/poly-Si/Si and BST/Ru-O/Ru/TiN/poly-Si/Si systems for broadening the process window of a sputtered TiN diffusion barrier are better than the and the systems. © 2001 The Electrochemical Society. All rights reserved.