The performance of LaAlO x gate dielectric films prepared by sol-gel method at different temperatures of annealing

Abstract In recent years, there has been growing interest in the exploration of rare earth oxides for their potential as high-k gate dielectrics. Lanthanum oxide (La₂O₃) has emerged as a particularly noteworthy candidate due to its impressive dielectric properties, wide bandgap, strong thermodynamic stability, and remarkable compatibility with silicon substrates. However, La₂O₃ has a significant problem for MOS device applications due to its hygroscopicity and low crystallization temperature, making it unsuitable for high-temperature treatment during fabrication. To improve its oxide quality, it can be doped. Al-doped La₂O₃ (LaAlOx) thin films annealed at different temperatures were prepared on n-type Si substrates by sol-gel method and the effect of temperature variation on LaAlOx thin films as gate dielectrics were investigated in terms of root-mean-square, interfacial properties, and electrical properties. The findings indicate that the introduction of Al doping raises the crystallization temperature of La₂O₃. Additionally, it was observed that the root-mean-square roughness of the LaAlOx films decreases from 0.919 nm to 0.320 nm with an increase in annealing temperature from 500 to 700°C. XPS has the capability to assess the interfacial characteristics of LaAlOx. It is evident that elevated temperatures promote the formation of M-O bonds, diminish film defects, and enhance the overall interfacial quality of the film. In addition, analyzed the electrical properties of the Al/ LaAlOx/Si/Al metal-oxide-semiconductor capacitors The findings indicate that the samples annealed at 700°C exhibit favorable electrical characteristics, demonstrating a dielectric constant of 20.91 under a gate voltage of 1 V and a leakage current density of 3.54×10⁻ ³A/cm².