In order to investigate the nature of defects produced by ion irradiation through a heterostructure, a Si-on-insulator substrate with a buried SiO2 layer at a depth of about 1.5µm was irradiated. The implantation was done using 2MeV 28Si+ ions in the dose range of 2 x 1015 to 1016/cm2. The subsequent defect analysis was performed using the Au labeling technique. Besides the presence of an expected excess of vacancy-type defects in the Si overlayer, an additional vacancy excess peak was observed at the front side of the buried interface. The latter value was found to increase linearly with increasing dose of the high-energy implant. The presence of a peak value near to the interface was also predicted by a Monte Carlo code. Additional Monte Carlo simulations of damage

production via high-energy implantation in Si/X-type structures showed that the nature of the defects at the front Si/X interface could be changed from vacancy to interstitial-type by increasing the mass of atoms in the buried thin-film, X. These experiments provide quantitative verification of non-uniform defect production at an ion-irradiated buried interface in Si.

Character of Defects at an Ion-Irradiated Buried Thin-Film Interface. R.Kalyanaraman, T.E.Haynes, O.W.Holland, G.H.Gilmer: Journal of Applied Physics, 2002, 91[10], 6325-32