For future generations of non-volatile memory applications, the replacement of the interpoly dielectric by a suitable high-k material is required. Rare-earth aluminates are potential candidates because they are predicted to combine a high dielectric permittivity with a large band gap. We demonstrate the atomic layer deposition (ALD) of Gd x Al 2-x O 3 layers using Gd(

GdxHf1−xnormalOy thin films were deposited by atomic layer deposition (ALD) using tris(isopropyl-cyclopentadienyl) gadolinium [Gd(normalPirCp)3] and HfCl4 in combination with normalH2O as an oxidizer. Growth curves showed a nearly ideal ALD behavior. The growth per individual Gd(normalPirCp)3/normalH2O or HfCl4/normalH2O cycle was 0.55 Å, independent of the Gd/(Gd+Hf) composition x in the studied range. This indicates that the amount of HfO2 deposited during a HfCl4/normalH2O cycle was essentially identical to the amount of Gd2normalO3 deposited during a Gd(normalPirCp)3/normalH2O cycle, assuming identical atomic densities of the films independent of composition. The crystallization of GdxHf1−xnormalOy with Gd/(Gd+Hf) contents x between 7 and 30% was studied. Films with x≳10% crystallized into a cubic/tetragonal HfO2 -like phase during spike or laser annealing up to 1300°C , demonstrating that the cubic/tetragonal phase is thermally stable in this temperature range. A maximum dielectric constant of κ∼36 was found for a Gd/(Gd+Hf) concentration of x∼11% .

An aqueous deposition process for V(6)O(13) films is developed whereby the vanadium oxidation state is continuously controlled throughout the entire process. In the precursor stage, a controlled wet chemical reduction of the vanadium(V) source with oxalic acid is achieved and monitored by (51)Vanadium Nuclear Magnetic Resonance ((51)V-NMR) and Ultraviolet-Visible (UV-Vis) spectroscopy. The resulting vanadium(IV) species in the aqueous solution are identified as mononuclear citrato-oxovanadate(IV) complexes by Electron Paramagnetic Resonance (EPR) and Fourier Transform Infra-Red (FTIR) spectroscopy. This precursor is successfully employed for the deposition of uniform, thin films. The optimal deposition and annealing conditions for the formation of crystalline V(6)O(13), including the control of the vanadium oxidation state, are determined through an elaborate study of processing temperature and O(2) partial pressure. To ensure a sub 100 nm adjustable film thickness, a non-oxidative intermediate thermal treatment is carried out at the end of each deposition cycle, allowing maximal precursor decomposition while still avoiding V(IV) oxidation. The resulting surface hydrophilicity, indispensable for the homogeneous deposition of the next layer, is explained by an increased surface roughness and the increased availability of surface vanadyl groups. Crystalline V(6)O(13) with a preferential (002) orientation is obtained after a post deposition annealing in a 0.1% O(2) ambient for thin films with a thickness of 20 nm.