STRUCTURAL AND ELECTRICAL DAMAGE INDUCED BY HIGH-ENERGY HEAVY-IONS IN SIO2/SI STRUCTURES

The structural and electrical properties of SiO2/Si structures irradiated by high-energy (> 0.5 GeV) Xe and Ni ions have been investigated. Structural analysis of the irradiated SiO2 films, performed with infrared spectroscopy, points to atomic displacements and broken and strained Si-O bonds induced by the irradiation. Using ir data, the damage cross section of the Xe and Ni ions has been deduced. The values are of about 8 x 10(-13) and 6 x 10(-14) cm2 for, respectively, 762 MeV Xe and 551 MeV Ni ions. Electrical measurements of irradiated SiO2/Si structures show an increase of the interface-state density D(it) and of the oxide trapped-charge density N0t with the ion fluence. These results are compared with defects induced by heavy-ion irradiation in bulk silica and by light particle radiation in silicon dioxide. Electrically active point defects have been detected in irradiated silicon and are associated with vacancy complexes.