High energy high dose Si implantation into Ge and the effect of subsequent thermal annealing

Abstract

A mirror polished (111)-oriented Ge single crystal substrate was implanted with 1.0 MeV Si+ ions to a dose of ∼ 8.5 × 1017 cm−2 at room temperature. Rutherford backscattering spectrometry (RBS) together with ion channeling analysis with H+ and He+ beams have been used to study the Si distribution and radiation damage after implantation and subsequent vacuum annealing in the temperature range of 500–850°C. A non-RBS (resonance) measurement with an H+ beam of specified energy is used to study the Si atoms distribution in Ge. The experiments reveal the existence of an extensive damage (possibly an amorphous layer) buried at a depth corresponding to the peak Si concentration. Annealing up to 850°C for 30 min does not result in the complete recovery of the lattice order. The annealing temperature dependence of the damage depth distributions in Ge has been evaluated using the multiple scattering model of Feldman and Rodgers. The composition of the alloy layer was measured by RBS followed by computer-simulated spectrum analyses. A tentative explantation of the results is presented.