Experimental investigation of the energy and depth dependence of flux peaking

The yield of helium ions backscattered from Yb implanted in silicon crystals has been studied as a function of the angle between the incident beam direction and various symmetry axes of the silicon crystal. The depth of the implanted Yb has been varied by using different implantation energies, and the analyzing beam energy has been varied from 0.5 to 2 MeV in an effort to obtain information about the energy and depth dependence of the flux-peaking phenomenon. The results are compared with those of Andersen and coworkers. We have observed the oscillation with depth of the flux in the center of a channel predicted by Van Vliet.