Ion-Beam Induced Mixing Processes and Gas Sputtering

Abstract

<p>Section I of this report discusses ion-beam induced mixing processes in solid targets. It is shown theoretically that cascade mixing can be approximated as a diffusion process. Further calculations attempt to show that some of the phenomena of ion-plating can be explained by this mixing process. Experimental data was obtained on the mixing of thin (~200 nm) layers of Ag into a Si substrate by bombardment with 35keV Ar+ ions, at fluences up to 6 x 10^14 ions/mm2. The results were observed by 2.0 MeV He+ ion Rutherford backscattering.</p> <p>In Section II, the release of trapped Kr from Ni is discussed. Kr, doped with radioactive 85Kr*, was implanted as 20keV ions, and subsequently released by post-bombardment with 5keV, 20keV and 80keV Kr+ ions. Three sets of Ni samples were Kr implanted to fluences of 5 x 10^12 ions/mm2, 5 x 10^13 ions/mm2 , or 5 x 10^14 ions/mm2 . The post-bombardment was carried out to fluences ranging from 5 x 10^12 ions/mm2 to 3.5 x 10^14 ions/mm2 . The relative quantities of trapped Kr * were determined by counting radioactive decay events for a fixed time interval.</p> <p>The results of this preliminary work show that many more experiments are required before these processes can be well-understood.</p>