High-energy (Rutherford) ion-scattering, in conjuncion with channeling techniques, provides a simple and direct method of measuring surface relaxation. Its sensitivity is comparable to LEED, but it avoids many of the interpretative difficulties. We report an experimental study of the relaxation of a (111) platinum surface using MeV He+ backscattering. An outward relaxation of (0.31 ± 0.06) Å was obtained for surfaces with monolayer coverages of adsorbed oxygen.

We have investigated the number, ${N}_{d}$, of displaced lattice atoms in room-temperature implantation in Si of polyatomic-carbon-ion beams (${{\mathrm{C}}_{n}}^{+}$ and ${\mathrm{C}}_{n\ensuremath{-}x}{{\mathrm{O}}_{x}}^{+}$) for several values of $n$, using the backscattering-channeling-effect technique. For each ion species the same energy (8.8 keV) per carbon and the same atomic fluence and flux were used. ${N}_{d}$ increases rapidly with increasing $n$, indicating that the deposited-energy density within the collision cascade is a key factor in determining how much damage is created and retained.

The ion channeling technique has been used to investigate surface relaxation effects in Pt. Preliminary results for a (111) surface indicate an outward relaxation of 0.31 ± 0.06 Å.

Bombardment-induced damage in single crystals of tungsten and niobium, implanted with 300-keV Ar+ at 25°K, has been examined by means of the channeling-effect technique. Target temperature was maintained at 25°K throughout the implantation and subsequent analysis in order to minimize annealing effects. Very high implantation doses (compared with doses involved in semiconductor work) had to be used before significant damage was observed. This would indicate that a strong spontaneous recovery occurs in these metals even at 25°K. The damage was seen mainly as an enhanced dechanneling component. In niobium a slight indication of a damage peak was also observed. Preliminary annealing studies did not show any significant annealing stages between 25°K and 300°K in the case of tungsten, while some annealing between 25°K and 300°K was observed in niobium.