Perturbations of the Sputtering Yield

Abstract

For low doses of implanted ions there is excellent agreement between the theoretical and measured parameters of ion range and sputtering yield. In the case of high doses the substrate is modified by the implant and one must use revised estimates of the range, energy loss and sputtering efficiency. This review will indicate that important variables include the flatness of the original surface; radiation enhanced diffusion; bubble and void formation; aggregation of new crystalline phases; and preferential sputtering. Preferential sputtering may occur because one is producing a new material during the implantation; similarly, bombardments of compound materials frequently produce preferential sputtering. In insulators and semiconductors secondary processes of preferential sputtering result from electronic excitation in the lattice.

On leave of absence from the School of Mathematical and Physical Sciences, University of Sussex, Brighton, BNl 9QH, England.