Interfacial reactions of Gd- and Nb-oxide based high-k layers deposited by aqueous chemical solution deposition

Abstract

In this work, ultrathin layers of GdOx, NbOx and GdNbOx, deposited with ACSD have been investigated. Because of the high temperature anneals utilized in the process flow of electronic devices, interactions of the deposited high-k materials and the substrate are analyzed. The deposited layers of GdOx, NbOx and GdNbOx on SiO(2) and Al(2)O(3) are annealed in an oxidizing and inert atmosphere and studied by XRD, GATR-FTIR and ellipsometry to assess layer-substrate interactions and crystallization behavior. With temperatures up to 900 degrees C, some minor interactions with the SiO(2)/Si substrates and no interaction with the Al(2)O(3) substrate were observed. At 1000 degrees C, however, more intense interactions with both substrates in both ambients are observed (severe silicate formation, interlayer regrowth and interaction with Al(2)O(3)). HT-XRD on the deposited layers shows that all the layers crystallized well below 900 degrees C. It is concluded that GdNbOx could be a more advantageous high-k material, compared to its monometal counterparts, based on its limited interaction with the substrate at high temperatures and in oxidative ambient. (C) 2011 Elsevier B.V. All rights reserved.