In situ phase-modulated ellipsometry study of the surface damaging processof silicon under atomic hydrogen

We employed in situ phase-modulated ellipsometry in the monitoring of surfa ce damage to monocrystalline silicon (Si) under plasma conditions typical f or the chemical vapor deposition of diamond. Single-wavelength kinetic and spectroscopic ellipsometry measurements were done and complemented with Ram an spectroscopy, in order to characterize the surface conditions. It was fo und that heating the Si substrate to 700 degrees C in the presence of molec ular hydrogen produces etching of the native oxide layer. When the hot bare silicon surface is submitted to atomic hydrogen, it becomes rough in minut es. Modeling of the spectroscopic ellipsometry provided a quantitative phys ical picture of the surface damage, in terms of the roughness layer thickne ss and void fraction. The results indicate that by the time a thin film sta rts to grow on these silicon surfaces, like in the chemical vapor depositio n of diamond, the roughness produced by the atomic hydrogen has already det ermined to a large extent the rough nature of the film to be grown. (C) 200 0 Elsevier Science Ltd. All rights reserved.