Impact of microstructure on electrical characteristics of laser ablation grown $ZrTiO_4$ thin films on Si substrate

Victor, P and Krupanidhi, SB (2005) Impact of microstructure on electrical characteristics of laser ablation grown $ZrTiO_4$ thin films on Si substrate. In: Journal of Physics D: Applied Physics, 38 (1). pp. 41-50.

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Abstract

Zirconium titanate thin films were deposited on a p-type Si substrate using the pulsed excimer laser ablation technique and the thin films were either highly oriented along (020) or were of a polycrystalline nature, depending upon the processing conditions. A detailed structural characterization using atomic force microscopy, scanning electron microscopy, x-ray photoelectron spectroscopy (XPS) and x-ray diffraction of the highly oriented and polycrystalline $ZrTiO_4$ thin films were carried out. The XPS of highly oriented $ZrTiO_4$ thin films deposited on Si substrates was characterized. The O 1s spectrum did not show any splitting, indicating there is no possibility of adsorbed oxygens, and the single peak in O 1s is attributed to the oxygen ions in the lattice. Capacitance–voltage (C–V ), conductance–voltage (G–V ) and dc leakage current studies were done on both types of thin film. Secondary ion mass spectrometer studies revealed a reasonably sharper interface existing at the thin film/substrate for the polycrystalline films, compared with the highly oriented thin films. A higher dielectric constant and higher leakage current were observed for the highly oriented $ZrTiO_4$ thin films compared with polycrystalline thin films. The C–V and G–V studies were carried in the frequency regime of 1–100 kHz on both types of film at higher temperatures (300–500 K) so as to make the minority carriers of the Si substrate respond to the applied ac modulating signal. The activation energies calculated from the Arrhenius plot from C–V and G–V measurements were nearly equal to half of the silicon energy band gap, thereby suggesting a generation–recombination mechanism prevailing in the depletion region of the Si substrate through bulk traps. The interface traps were calculated using the high frequency method and observed to be higher for the polycrystalline films than for the highly oriented thin films. Dc leakage current studies were done in the accumulation region and both the highly oriented and polycrystalline thin films obeyed a bulk limited Poole–Frenkel type conduction mechanism. Finally, the electrical characteristics were correlated to the microstructure of zirconium titanate thin films.

Item Type:	Journal Article
Publication:	Journal of Physics D: Applied Physics
Publisher:	IOP Publishing Ltd
Additional Information:	The Copyright belongs to IOP Publishing Ltd.
Department/Centre:	Division of Chemical Sciences > Materials Research Centre
Date Deposited:	17 Mar 2006
Last Modified:	19 Sep 2010 04:24
URI:	http://eprints.iisc.ac.in/id/eprint/5822

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