Dechanneling by dislocations in ion-implanted Al

The influence of dislocations on the dechanneling of energetic channeled ions has been investigated. Channeling effect and transmission electron microscopy (TEM) techniques were used to measure the disorder in 1.2 to 2.6 x 10l6/cm2 Zn-implanted Al crystals. Channeling analysis along the axis was made with He beam energies ranging between 1.0 and 3.0 MeV. From TEM measurements, a dense network of dislocations is found to be the predominant type of defect in the implanted layer. From our analysis of the energy dependence of the dechanneling, together with the TEM determination of the total projected dislocation length, we obtain the first experimental measurement by backscattering of the dechanneling cross section, λ, for a dislocation. The experimental value, λ(A) = 20[E(MeV)]1/2 agrees closely in magnitude and in energy dependence with theoretical prediction. From these studies, we estimate that the minimum dislocation density for detection by channeling is 109–1010 cm length of 1ine/cm3.