Diffusion and incorporation of Zr into thermally grown SiO2 on Si(100)

We have studied the Zr diffusion into ultrathin thermally grown SiO2 on Si(1 0 0) from Zr-rich oxides at 750 - 1000 degreesC in N-2 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 degreesC can be characterized as the cases under constant-surface-concentration conditions with the diffusion constants of similar to1 x 10(-19) cm(2)/s at 750 degreesC and similar to1 x 10(-18) cm(2)/s at 900 degreesC, while the diffusion at 1000 degreesC 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. (C) 2003 Elsevier Science B.V. All rights reserved.