Ellipsometric investigation of the Si/SiO2 interface formation for application to highly reflective dielectric mirrors

We present a study of the Si/SiO2 interface formation during the growth of Si on SiO2 using in situ ellipsometry measurements performed at one wavelen gth (lambda = 0.4 mum). Variable angle X-ray photoelectron spectroscopy (XP S) is also used to confirm the ellipsometric measurements. In situ ellipsom etry and XPS provide evidence for the formation of a SiOx (0 < x < 2) inter layer between the SiO2 and Si layers. The variation of x with depth is anal ysed from (cos Delta, tan psi) trajectories and the results obtained allow reproduction of the spectroscopic ellipsometry spectra too. The effects of the substrate temperature on the growth are investigated and show that the higher the substrate temperature the larger the interface. The utilisation of a SiO2/Si multilayer stack for elaborating an omnidirectional reflector, angle-insensitive in the near infrared range, is also presented. (C) 2000 Elsevier Science B.V. AU rights reserved.