Iron contamination in ion implanted silicon, as revealed by x-ray and electron diffraction

Abstract

A surface contamination effect was detected by double-crystal x-ray diffraction analysis of silicon wafers implanted with silicon ions at different doses and energies after annealing at 700 °C.

The hypothesis of recoiled oxygen from the native oxide, as the impurity responsible for surface strain, was excluded by x-ray characterization of a series of samples implanted through thermally grown silicon oxides. The surface positions of the strain, resulting from x-ray analysis after 700 °C annealing and the analysis of the electron diffraction patterns, taken on particles originated from precipitation of the impurity by 1000 °C heating, allowed to conclude that the contamination phenomenon is due to iron atoms coming from the ion implanter.