Modulation of the microstructure, optical and electrical properties of sputtering-driven Yb2O3 gate dielectrics by sputtering power and annealing treatment

Abstract

The effect of sputtering power and annealing temperature on the microstructure, optical and electrical properties of sputtering-derived Yb2O3 high-k gate dielectrics on Si substrate have been investigated systematically. Based on measurements by ultraviolet-visible spectroscope (UV-Vis) and spectroscopic ellipsometry (SE), the increase in band gap and reduction in refractive index have been detected. Structural analyses by x-ray diffraction (XRD) reveal that the Yb2O3 thin films exhibit a cubic phase at higher annealing temperature. X-ray photoelectron spectroscopy (XPS) analyses demonstrate the decreased Yb silicate and low-k SiO2 interfacial layer for the samples annealed at 300 °C. Electrical measurements have indicated that Yb2O3/Si gate stacks annealed at 300 °C shows excellent dielectric performance with leakage current density of 3.66 × 10−8 A/cm2 at applied voltage of 1 V. As a supplement, the leakage current conduction mechanisms of MOS capacitor for different annealing temperature have been discussed systematically.