Diffusion and incorporation of Zr into thermally grown SiO2 on Si(1 0 0)

We have studied the Zr diffusion into ultrathin thermally grown SiO2 on Si(1 0 0) from Zr-rich oxides at 750–1000 °C in N2 ambient with combination of photoemission measurements and wet-chemical SiO2-thinning in a dilute HF solution. The chemical bonding features incorporated Zr atoms into SiO2 and the influence of the Zr incorporation on the gap states have also been evaluated by analyzing X-ray photoelectron and total photoelectron yield spectra, respectively. The measured Zr depth profiles show that the Zr diffusion at 750 and 900 °C can be characterized as the cases under constant-surface-concentration conditions with the diffusion constants of ∼1×10−19 cm2/s at 750 °C and ∼1×10−18 cm2/s at 900 °C, while the diffusion at 1000 °C is likely to be the case under a constant-total-concentration condition. No increase in the gap states with Zr incorporation into SiO2 is confirmed by total photoelectron yield measurements.