Interfacial modulation and optimization of the electrical properties of ZrGdO composite films prepared using a...

In this paper, Gd-doped ZrO₂ gate dielectric films and metal-oxide-semiconductor (MOS) capacitors structured as Al/ZrGdO /Si were prepared using an ultraviolet ozone (UVO)-assisted sol-gel method. The effects of heat treatment temperature on the microstructure, chemical bonding state, optical properties, surface morphology and electrical characteristics of the ZrGdO composite films and MOS capacitors were systematically investigated. The crystalline phase of the ZrGdO films appeared only at 600 °C, indicating that Gd doping effectively inhibits the crystallization of ZrO₂ films. Meanwhile, as the heat treatment temperature increased from 300 °C to 600 °C, the content of oxygen vacancies decreased from 18.57% to 11.95%, and the content of metal-hydroxyl-oxygen bonds decreased from 14.72% to 8.64%. Heat treatment temperature proved to be effective in passivating the oxygen defects and reducing the trap density within the dielectric layer. At 500 °C, the MOS capacitor exhibited the best electrical characteristics, including the highest dielectric constant (k = 19.3), the smallest hysteresis (ΔV _fb = 0.01 V), the lowest boundary trapping oxide charge density (N _bt = 2.7 × 10¹⁰ cm^-2), and the lowest leakage current density (J = 9.61 × 10^-6 A cm^-2). Therefore, adjusting the heat treatment temperature can significantly improve the performance of ZrGdO composite films and capacitors, which is favorable for the application of CMOS devices in large-scale and high-performance electronic systems.