Study of SHI induced recrystallization effects in SOI structures synthesized by nitrogen and oxygen ion implantation in silicon

Abstract

Silicon oxynitride (Si x O y N z ) buried insulating layers were synthesized by implantation of nitrogen ( 14N +) and oxygen ( 16O +) ions sequentially in the ratio 1:1 at 150 keV to ion-fluences ranging from 1 × 10 17 to 5 × 10 17 cm −2 to prepare silicon on insulator (SOI) structures. The as implanted samples were held at 270 °C and irradiated to total fluence of 1 × 10 14 cm −2 by 60 MeV Ni +5 to study the structural changes/recrystallization of SOI structures induced by swift heavy ion (SHI) irradiation. Fourier transform infrared (FTIR) measurements on the as implanted samples (≤1 × 10 18 cm −2) show a single absorption band in the wavenumber range 1300–750 cm −1 attributed to the formation of silicon oxynitride (Si–O–N) bonds in the implanted silicon. It is observed that a nitrogen rich silicon oxynitride structure is formed after SHI irradiation. The study of X-ray rocking curves on the samples show the formation of small silicon crystallites due to swift heavy ion irradiation.