Effects of aluminum doping on lanthanum oxide gate dielectric films

This work reports a novel method for improving the electrical properties of lanthanum gate oxide (La2O3) by using aluminum doping and rapid thermal annealing (RTA) techniques. In the bulk of the AI-doped La2O3 film together with 600 degrees C RTA, we found that the aluminum atoms were incorporated into the oxide network and the film was transformed into lanthanum aluminate complex oxide. At the interface, a thin Al2O3 layer was formed. This interfacial Al2O3 layer suppressed the out-diffusion of substrate Si, the formation of interfacial silicate layer and silicide bonds. These effects resulted in a significant reduction on the bulk and interface trap densities and hence the gate leakage current. (C) 2011 Elsevier Ltd. All rights reserved.