Low-damage processing using size-controlled gas cluster ion beams

Gas cluster ion beam (GCIB) process has been used as a novel technique to realize very low-damage irradiations. The energy per atom of cluster ions can be reduced down to several eV/atom at several keV of total acceleration energy. In this study, size-controlled GCIB was formed using a strong permanent magnet, subsequently low-damage characteristics of large cluster ion irradiations were evaluated from the cross-sectional transmission electron microscope (TEM) observations of Si substrates. After size-controlled GCIB irradiation, the damaged or modified layer thickness was below several nm, when total acceleration energy was 5 keV and Ar cluster size was larger than 5000. Result obtained from spectroscopic ellipsometry also indicated the possibility of low-damage processing by size-controlled GCIB. (c) 2007 Elsevier B.V. All rights reserved.