Effect of UV lamp irradiation during oxidation of Zr/Pt/Si structure on electrical properties of Pt/ZrO2/Pt/Si structure

Metal-insulator-metal (MIM) capacitors were fabricated using ZrO2 films and the effects of structural and native defects of the ZrO2 films on the electrical and dielectric properties were investigated. For preparing ZrO2 films, Zr films were deposited on Pt/Si substrates by ion beam deposition (IBD) system with/without substrate bias voltages and oxidized at 200 °C for 60 min under 0.1 MPa O2 atmosphere with/without UV light irradiation (λ = 193 nm, Deep UV lamp). The ZrO2(∼12 nm) films on Pt(∼100 nm)/Si were characterized by X-ray diffraction pattern (XRD), field emission scanning electron microscopy (FE-SEM) and high-resolution transmission electron microscopy (HRTEM), capacitance-voltage (C-V) and current-voltage (I-V) measurements were carried out on MIM structures. ZrO2 films, fabricated by oxidizing the Zr film deposited with substrate bias voltage under UV light irradiation, show the highest capacitance (784 pF) and the lowest leakage current density. The active oxygen species formed by UV irradiation are considered to play an important role in the reduction of the leakage current density, because they can reduce the density of oxygen vacancies.