Lanthanide Oxide Thin Films by Metalorganic Chemical Vapor Deposition Employing Volatile Guanidinate Precursors

The application of two novel metalorganic complexes, namely the isostructural tris(N,N'-diisopropyl-2-dimethlyamido-guanidinato)gadolinium(III) (1) and tris(N,N’-diisopropyl-2-dimethlyamido-guanidinato)dysprosium(III) (2) as precursors for metalorganic chemical vapor deposition (MOCVD) of Gd2O3 and Dy2O3 is discussed. On the basis of the detailed thermal gravimetric analysis (TGA) and isothermal TGA studies, both the precursors are very volatile and able to deliver continuous mass transport into the gas phase. The extraordinary thermal stability of the precursors was revealed by nulcear magnetic resonance (NMR) decomposition studies. Depositions were carried out in the presence of oxygen at reduced pressure and varying the substrate temperature in the range 300-700 °C. Uniform films with reproducible quality were deposited on Si(100) and Al2O3(0001) substrates over the entire temperature range. Employing a multitechnique approach (XRD, SEM, AFM, EDX, XPS, RBS, SNMS, C-V), variations of the growth characteristics and film properties with deposition temperature are studied in terms of crystallinity, structure, surface roughness, composition, and electrical properties.