Thin Film Properties of Sol-Gel Derived High-K Lanthanum-Doped Zirconium Oxides

Abstract

The lanthanum zirconium oxide thin films were prepared on p-type Si(100) by a sol-gel wet method. Sol-gel solutions of La _x Zr _{1 − x} O _y with La atomic fractions of x = 0, 0.05, 0.1, 0.3, and 0.5 were synthesized for film deposition. Thin films were characterized using x-ray diffraction (XRD), atomic force microscopy (AFM), and scanning electron microscopy (SEM). Electrical property characterization was performed with metal-insulator-semiconductor (MIS) structures through capacitance-voltage (C-V) and current density-voltage (J-V) measurements. The thin film showed a good surface morphology. Equivalent oxide thickness (EOT) values of 30 nm-thick La _x Zr _{1 − x} O _y thin films annealed at 700°C were about 8.8–10.5 nm. C-V measurements revealed that curves shifted left when the film has a larger content of La or was annealed at a higher temperature. The leakage current density was below 1.0 × 10⁻⁶ A/cm ² at 1 MV/cm for all samples.

Keywords:

• High-k
• dielectric
• sol-gel
• lanthanum-doped zirconium oxide

Acknowledgment

This work was supported by the research grant from the Seoul R&BD Program (10592).