Structural and nuclear characterizations of defects created by noble gas implantation in silicon oxide

摘要

Thermally grown silicon oxide layer was implanted at room temperature with 300 keV Xe at fluences ranging from 0.5 to 5 x 10~(16) Xe/ cm~2. Bubbles created after Xe-implantation provided a low-k silicon oxide that has potential use as a dielectric material for interconnects in Si integrated circuits. Transmission Electron Microscopy (TEM), Rutherford Backscattering Spectrometry (RBS) and Positron Annihilation Spectroscopy (PAS) were used to provide a comprehensive characterization of defects (bubbles, vacancy, gas atoms and other types of defects) created by Xe implantation in SiO_2 layer. These measurements suggest that the bubbles observed with TEM for all fluences were a consequence of the interaction between Xe and vacancies (V), with V_nXe_m complexes created in the zone where V and Xe profiles overlap. Negatively charged defects such as (Si-O~-, Si-O-O~- and O_2~-) are also created after implantation.