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Structural, optical, and electrical characterization of gadolinium oxide films deposited by low-pressure metalorganic chemical vapor deposition

Singh, MP and Thakur, CS and Shalini, K and Banerjee, S and Bhat, N and Shivashankar, SA (2004) Structural, optical, and electrical characterization of gadolinium oxide films deposited by low-pressure metalorganic chemical vapor deposition. In: Journal of Applied Physics, 96 (10). pp. 5631-5637.

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Abstract

We report the growth and characterization of gadolinium oxide films deposited on Si(100) and fused quartz in the temperature range of 450–800 °C by a low-pressure metalorganic chemical vapor deposition technique using a $\beta$-diketonate complex of gadolinium as the precursor. The x-ray diffractometry study of the films reveals that, irrespective of the growth temperature, the films grown on fused quartz (i.e., an amorphous substrate) and silicon (i.e., a single-crystal substrate) comprise the cubic $Gd_2O_3$ phase with a (111) texture. However, the films grown on fused quartz at higher temperatures also show the presence of the monoclinic phase of $Gd_2O_3$. The growth of strongly oriented films on fused quartz has been understood on the basis of minimization of the surface energy. The scanning electron microscopy and atomic force microscopy studies reveal that the films grown at or above 525°C are densely packed and grainy. Optical properties of the films, as studied by ultraviolet (UV)-visible spectrophotometry and Fourier transform infrared spectroscopy, are found to depend strongly on the chemical vapor deposition condition. The analyses reveal further that the films grown at or above 500 °C are free of heteroatoms, i.e., C, N, and H. The optical band gap of the films is in the range of 5.0–5.4 eV. Electrical characterization was carried out on $Al/Gd_2O_3 /Si$ metal-insulator-semiconductor structures by capacitance–voltage (C–V) and current–voltage analyses. The effective dielectric constant of the films was in the range of 7–23. The bidirectional C–V characteristics show a counterclockwise hysteresis due to the presence of slow interface traps. A minimum leakage current of $4.6X10^{-5} \hspace {2mm} A/cm^2$ at the 1-MV / cm field was demonstrated.

Item Type: Journal Article
Additional Information: The copyright of this article belongs to American Institute of Physics.
Department/Centre: Division of Chemical Sciences > Materials Research Centre
Division of Electrical Sciences > Electrical Communication Engineering
Date Deposited: 22 Mar 2006
Last Modified: 19 Sep 2010 04:25
URI: http://eprints.iisc.ernet.in/id/eprint/6118

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