Observation of swelling and sputtering of a silicon target under argon ion irradiation using a double marker technique

The process of ion implantation results in sputtering at the surface and contraction and/or swelling in the bulk. This has been measured for 150 keV Ar+ implanted into amorphous silicon films by sectioning the collision cascade with a double marker technique and observing the movement of the markers employing Rutherford Backscattering Spectrometry. The experimental data are compared with a computer simulation programma Trim-Cascade. The results for implant doses of 1x1016, 2x1016, and 5x10sup16 ions cm-2 consistently indicate a common crossover depth between a sputtering and contraction dominated regime and a regime dominated by swelling. Excess contraction due to vacancies observed in the region of maximum nuclear energy deposition suggests radiation enhanced diffusion of interstitials towards greater depth. (author)