Comparative study of ion implantation caused anomalous surface damage in silicon studied by spectroscopic ellipsometry and Rutherford backscattering spectrometry

Damage created by ion implantation of 150 keV Ne+ and 800 keV Ar+ ions in single-crystalline silicon was characterized using Spectroscopic Ellipsometry (SE) and Rutherford Backscattering Spectrometry (RBS) in combination with channeling. Results from both methods unambiguously show the presence of a heavily damaged thin layer at the surface that is not predicted by TRIM calculations. The amorphization rate at the surface was found to be proportional to the nuclear energy deposition at the surface. It is demonstrated that SE cross-checked with RES could be used for quantitative and accurate evaluation of the thickness of the damaged surface layer. The formation of this thin amorphous layer could be attributed to the redistribution of Si interstitials produced by the implantation process from the buried damaged region towards the surface and to a subsequent segregation process CN. Fukarek et al., Nucl. Instr. and Meth. B 127/128 (1997) 879). (C) 1999 Elsevier Science B.V. All rights reserved.