Comparative study of structural electrical dielectric and ferroelectric properties of HfO2 deposited by plasma-enhanced atomic layer deposition and radio frequency sputtering technique for the application in 1-T FeFET

Abstract

For this proposed work, the comparison of structural, electrical, dielectric, and ferroelectric properties of HfO2 film deposited by plasma-enhanced atomic layer deposition (PEALD) and radio frequency (RF) sputtering technique. Various characteristics has been obtained by fabricating the metal-ferroelectric-silicon (MFeS) and metal-ferroelectric-metal (MFeM) capacitors with different thickness of HfO2 (5, 10, 15, 20 nm) as a ferroelectric layer deposited on silicon and TiN/Silicon. The structural properties such as crystallographic phase, grain size with composition and refractive index of the deposited film were measured by X-ray diffraction, Field emission scanning electron microscopy with energy dispersive spectroscopy (FESEM-EDS) and multiple angle ellipsometry with the variation in annealing temperature. MFeS and MFeM structure were fabricated to obtain electrical and ferroelectric properties such as memory window, leakage current density, closed loop hysteresis, remnant polarization, charge, coercive field voltage, data retention time, endurance, and breakdown voltage of the deposited film. MFeS structure shows the memory window and flat band voltage shift of 4 V and 1.72 V, respectively for 10 nm PEALD-deposited HfO2 layer. For the sputtered 15 nm film, maximum memory window of 4.32 V and leakage current density of 1.2 × 108 A/cm2 has been observed at the annealing temperature of 800 °C. Remnant polarization of 4 and 1.2 μC/cm2 obtained for PEALD and sputtered HfO2 film. The fabricated structure shows data retention for greater than 10 years and fatigue resistance for higher than 1012 read/write cycles. The reliability of the thin film was investigated by measuring the breakdown voltages of MFeS structure for different film thickness.