It was noted that the formation of sub-surface nm-sized cavities in Si, by He implantation followed by thermal annealing, involved a complex interaction of He with vacancy clusters. An attempt was made to promote cavity formation with vacancy-type defects arising from a H plasma treatment that was interposed between implantation (40keV or 160keV He) and annealing (800C, 1h). Cross-sectional transmission electron microscopy results revealed the enhanced growth of He-induced cavities due to H in 160keV He-implanted samples, while no significant change was seen in the cavity spectrum at 40keV. Together with secondary ion mass spectroscopy data, the results were tentatively interpreted in terms of the evolution of defects and H during annealing, their interactions with He-cavities and the proximity of the layers to the surface.

Enhancement of He-Induced Cavities in Silicon by Hydrogen Plasma Treatment. C.L.Liu, E.Ntsoenzok, A.Vengurlekar, S.Ashok, D.Alquier, M.O.Ruault, C.Dubois: Journal of Vacuum Science & Technology B, 2005, 23[3], 990-4