Spatial distribution of defects in ion bombarded silicon and germanium

Abstract

The damage produced in Si and Ge by 10–400 keV heavy-ion bombardment has been measured by using the channeling technique. By optimizing the experimental conditions, the depth distribution of the damage can be measured with a depth resolution of ∼ 10% in the range of 50–10000 Å. The present paper gives a short description of the method and the apparatus applied in these measurements. The results of the measurements may be summarized as follows: (i) The measured depth distributions demonstrate the necessity of taking the energy transported by recoils away from their point of origin into account. (ii) The average damage depth and the depth straggling agree with recent theoretical calculations of the distribution of energy deposited by ions in solids. (iii) The damage production exhibits a dose rate dependence indicative of room temperature annealing. This is supported by the observation of the annealing effect of a 0.5 MeV He bombardment. (iv) Channeling of a heavy ion has a marked influence on the damage produced by the ion. The depth and the width ot a damage distribution created by a channeled implantation are larger than those of a distribution from a non-channeled implantation, whereas the damage production in the former case is smaller than in the latter.