Temperature dependent growth of ytterbium oxide as gate dielectric on silicon substrate via combination of nitrogen and oxygen ambient.

The ongoing trend towards downsizing silicon (Si)-based metal-oxide semiconductor (MOS) devices has led to constraints on the silicon dioxide (SiO 2) gate dielectric due to increased leakage current through the thin SiO 2. In this study, ytterbium oxide (Yb 2 O 3) as a high dielectric constant (k) gate oxide material was deposited on a Si substrate and subjected to annealing at different temperatures ranging from 400 to 1000oC in a nitrogen-oxygen-nitrogen ambient atmosphere. The successful formation of Yb 2 O 3 was verified using X-ray diffraction (XRD), Fourier transform infrared (FTIR), and ultraviolet–visible (UV–VIS) spectroscopy. The FTIR analysis indicated that Yb 2 O 3 gate dielectrics post-annealing exhibited Yb-O bonding due to oxygen diffusion, as well as N-O bonding and NO 3 -bonding, demonstrating the formation of a nitrogen barrier at the interface to hinder oxygen diffusion. The optical band gap values of Yb 2 O 3 gate dielectrics post-annealing ranged from 3.092 eV to 3.267 eV. Notably, the Yb 2 O 3 gate dielectric annealed at 800 °C showed no breakdown within the 0–3 V range across all samples. The acquisition of a high k value of 19.40 and a low effective oxide charge (Q eff) of 5.32 x 1011 cm−2, along with the superior I-V characteristics, suggest that the Yb 2 O 3 gate dielectric annealed at 800oC has the potential to be employed for next generation MOS applications. [ABSTRACT FROM AUTHOR]