Plasma Enhanced Atomic Layer Deposited HfO₂ Ferroelectric Films for Non-volatile Memory Applications

Abstract

For this proposed work, structural, electrical and ferroelectric properties of metal-insulator-silicon (MIS) and metal-insulator-metal (MIM) capacitors with different HfO₂ (5 nm, 10 nm, 15 nm, 20 nm) thicknesses deposited on silicon and TiN/Silicon were investigated. The structural properties such as crystallographic phase, grain size with composition and refractive index of the plasma enhanced atomic layer deposited HfO₂ film was measured by x-ray diffraction, field emission scanning electron microscopy with energy dispersive spectroscopy and multiple angle ellipsometry. Memory window, leakage current density, closed loop hysteresis, remnant polarization, coercive field voltage, data retention time, endurance and breakdown voltage of the deposited film were the important measured electrical parameters. The MIS structure shows a maximum memory window of 4 V, and the MIM structure shows maximum remnant polarization of 4 μC/cm² for 10 nm HfO₂ layer. The structure shows data retention capability of more than 10 years and fatigue resistance for more than 10¹² read/write cycles.