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Ion backscattering spectrometry has been used to investigate the depth dependence of atomic mixing induced by ion beams. Samples consisting of a thin Pt (or Si) marker a few tens of angstroms thick buried at different depths in a deposited Si (or Pt) layer were bombarded with Xe+ of 300 keV at 2×1016 cm−2 dose and Ar+ of 150 keV at 5×1015cm−2 dose. Significant spreading of the marker was observed as a result of ion irradiation. The amount of spreading was measured as a function of depth of the marker, which was then compared with the deposited energy distribution. Measurements of this kind promise new insight into the nature of the interaction between ion beams and solids.

The formation of palladium silicide phases by implantation of Si ions into evaporated-palladium films on two different substrates (Si and SiO2) has been investigated. The amount and phase of silicide formed depend on the implantation temperature, substrate type, and the penetration of the ions relative to the substrate depth. Provided the ions do not penetrate to the substrate, it is found that Pd2Si is formed for both types of substrate, even at 150 °K. When the ions just reach the Pd/substrate interface, the sample temperature and substrate type become important. For the SiO2 substrate, the amorphous alloy Pd4Si forms at low temperatures. With the Si substrate Pd2Si forms under all conditions and there is a large incorporation of silicon from the substrate into the palladium, to an extent dependent on the temperature. This effect is explained in terms of radiation-enhanced diffusion, possibly assisted by dynamic cascade mixing. In the SiO2 substrate case, oxygen is thought to play an important role in determining the formation of phases.

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