Browsing by Author "Parala, Harish"

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    Lanthanide oxide thin films by metalorganic chemical vapor deposition employing volatile guanidinate precursors.
    (2009-11-24) Paul, Shashi; Milanov, Andrian P.; Toader, Teodor; Parala, Harish; Barreca, Davide; Gasparotto, Alberto; Bock, Claudia; Becker, Hans-Werner; Ngwashi, Divine K.; Cross, R. B. M.; Kunze, Ulrich; Fischer, Roland A.; Devi, Anjana
    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 Gd 2O3 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 Al 2O3(000l) 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.
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    Rare-Earth based Oxide and Nitride thin films employing volatile homoleptic guanidinate precursors.
    (The Electrochemical Society, 2009-10-09) Milanov, Andrian P.; Thiede, Tobias; Hellwig, Malte; Parala, Harish; Bock, Claudia; Becker, Hans-Werner; Ngwashi, Divine K.; Cross, R. B. M.; Paul, Shashi; Ukunze, Ulrich; Fischer, Roland A.; Devi, Anjana
    The application of the metalorganic compound tris(N,N'-diisopropyl-2-dimethlyamidoguanidinato)gadolinium(III) (1) as a precursor for MOCVD of Gd2O3 is discussed. Depositions were carried out in the presence of oxygen at reduced pressure and varying the substrate temperature in the range 300 - 700{degree sign}C. Employing a multi-technique approach (XRD, SEM, AFM, EDX, RBS, SNMS, SE, C-V), variations of the growth characteristics and film properties with deposition temperature are studied in terms of crystallinity, structure, surface roughness, composition, optical and electrical properties. In addition, the use of 1 as single source precursor for the MOCVD of GdN thin films is also demonstrated.
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    Rare-earth substituted HfO2 thin films grown by metalorganic chemical vapor deposition.
    (Elsevier, 2011-10-29) Devi, Anjana; Cwik, Stefan; Xu, Ke; Milanov, Andrian P.; Noei, Heshmat; Wang, Yuemin; Barreca, Davide; Meijerd, Jan; Rogallad, Detlef; Kahn, Divine; Cross, R. B. M.; Parala, Harish; Paul, Shashi
    Thin films of HfGdOx and HfDyOx were deposited by metalorganic chemical vapor deposition (MOCVD) utilizing guanidinate precursors for Hf, Gd and Dy. The close match in the thermal properties of the precursors enabled the MOCVD of rare-earth (RE) substituted HfO2 over a wide temperature window. Film deposition was carried out in the temperature range 300–700 °C in the presence of oxygen on Si(100) substrates. HfGdOx films were analyzed in detail for their structure, composition and morphology using X-ray diffraction, Rutherford backscattering spectrometry, proton induced X-ray emission, X-ray photoelectron spectroscopy and scanning electron microscopy. The electrical properties of HfGdOx in terms of capacitance–voltage and current–voltage characteristics of metal-insulator-semiconductor device structures were evaluated.
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    Sc2O3, Er2O3, and Y2O3 thin films by MOCVD from volatile guanidinate class of rare-earth precursors
    (Royal Society of Chemistry, 2012) Milanov, Andrian P.; Xu, Ke; Cwik, Stefan; Parala, Harish; De Los Arcos, T.; Becker, Hans-Werner; Rogalla, Detlef; Cross, R. B. M.; Paul, Shashi; Devi, Anjana