Bulg. J. Phys. vol.39 no.2 (2012), pp. 178-185

Oxidation of Si Surface Nitrogenated by Plasma Immersion N+ Ion Implantation

A. Szekeres1, S. Alexandrova2, E. Vlaikova1, E. Halova2
1Institute of Solid State Physics, 72 Tzarigradsko Chaussee, Sofia 1784, Bulgaria
2Technical University - Sofia, 8 Kl. Ohridski Blvd., Sofia 1797, Bulgaria
Abstract. Oxidation of nanoscaled Si surface layer modified by shallow low energy nitrogen plasma-beam ion implantation is studied. By postimplantation oxidation in dry O2 ambient SiOxNy layers are synthesized. Results on the kinetics of SiOxNy formation based on Deal & Grove oxidation model are presented. Oxidation rate decrease with ion fluence is observed and explained with nitrogen induced process retardation. The optical and structural properties of the layers are examined by FTIR and ellipsometric spectroscopies determining the layers as a mixture of SiO2 and Si3N4 with ratio of volume fractions varying with ion fluence. In the FTIR spectra a broad band between 650 and 1000 cm-1 associated to asymmetric stretching mode of Si-N is detected supporting the ellipsometric modelling.

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