Understanding the processes caused by ion implantation of light ions in dielectric

materials such as silica was important for developing the diagnostic systems used

in fusion and fission environments. Recently, it was shown that ion-implanted

helium was able to escape from SiO2 films. To study this process in details, helium

was implanted into the central part of a buried SiO2 island up to a fluence of 4 x

1017He/cm2. The implanted helium could be detected in the SiO2 island, if the

oxide was insulated properly from the vacuum. The shape of the helium depth

distributions was far from SRIM simulation because helium distributed in the

whole 1μm thick oxide layer. After the ion implantation, helium was observed only

on the implanted spot. After nine months the implanted helium filled out the whole

oxide island as it was expected from the high diffusivity.

Determination of Migration of Ion-Implanted Helium in Silica by Proton

Backscattering Spectrometry. G.Szakács, E.Szilágyi, F.Pászti, E.Kótai: Nuclear

Instruments and Methods in Physics Research B, 2008, 266[8], 1382-5