Electrical properties of atomic-layer-deposited La2O3 films using a novel La formamidinate precursor and ozone

Abstract

La2O3 films were grown by atomic layer deposition technique using a novel formannidinate precursor, tris(N,N'-diisopropylformamidinato) lanthanum [La((i)PrfAMD)(3)], with H2O and O-3 as an oxidant. La2O3 films grown with H2O in the film exhibited a parasitic chemical vapor deposition type growth possibly due to a La(OH)(x) component. However, the use of O-3 as the oxidant revealed a stable ALD process window. A post-deposition annealing (PDA) of the deposited La2O3 films using O-3 significantly reduces leakage current density by four orders of magnitude relative to as-deposited samples. The dielectric constant of La2O3 films with a TaN metal gate is found to be similar to 29, which is higher than reported values for CVD and ALD La2O3 films. (C) 2009 Elsevier B.V. All rights reserved.