Growth and electrical characterization of laser ablated highly oriented zirconium titanate thin films in a metal-oxide semiconductor configuration

Abstract

Highly oriented zirconium titanate (ZrTiO₄) thin films were deposited along the (020) direction on a p-type Si substrate using the pulsed excimer laser ablation technique. X-ray diffraction and energy dispersive analysis of ZrTiO₄ thin films reveal that they exhibit excellent phase and stoichiometry, respectively. Secondary ion mass spectrometer analysis has revealed that the presence of less thick native oxide is unavoidable and that a nearly sharper interface exists at the semiconductor-insulator interface. Electrical characterization was carried out on the highly oriented ZrTiO₄ thin films. The density of interface states and fixed oxide charges were calculated using capacitance-voltage (C-V) analysis and the obtained dielectric constant was greater than 19. The annealed films exhibited higher dielectric constant and lower fixed oxide charges than the as-grown thin films. The influence of temperature on the response of the C-V characteristics has been studied and the recombination-generation of charge carriers was found to be responsible for the transition of the C-V curve from high frequency to low frequency. The conduction mechanism was examined using dc leakage current characteristics, revealing the bulk limited Poole-Frenkel conduction mechanism as the dominant mechanism in the ZrTiO₄ thin films in a metal-oxide semiconductor capacitor.