High-Dielectric-ConstantMgZrO₃ by SprayPyrolysis for Thin-Fim Transistorsin Low-Power Electronics

This study presents the synthesis and characterization of MgZrO₃, a high-dielectric-constant (<i>k</i>) material tailored for nanocrystalline indium gallium zinc oxide (IGZO) thin-film transistors (TFTs). MgZrO₃ films were deposited via spray pyrolysis at 400 °C, yielding a uniform amorphous structure with enhanced surface quality, as confirmed by X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). A 30 nm MgZrO₃ film exhibited a high mass density of 5.76 g/cm³ and an RMS roughness of 0.29 nm, contributing to a low leakage current density (5.54 × 10^–7 A/cm²) at 4 MV cm^–1, a high dielectric constant (14.8), and a high breakdown electric field (5.16 MV cm^–1) in a metal–insulator–metal (MIM) structure. X-ray photoelectron spectroscopy (XPS) depth analysis revealed a robust metal-oxide bond ratio (∼75%) at the MgZrO₃/IGZO interface, with oxygen-related defects (∼25%), enhancing the electrical properties of MgZrO₃/IGZO TFTs. The IGZO TFT demonstrated high field-effect mobility (20 cm²/V·s), small subthreshold swing (88 mV/dec), and high on/off current ratio (∼10⁹), with zero hysteresis voltage and low gate leakage currents (∼10^–13 A). In addition, IGZO TFTs with MgZrO₃ dielectrics exhibited excellent bias stability under positive or negative bias stress and maintained their environmental stability over 90 days.