Electrical and structural characterization of defects introduced in p-SiGe during low energy erbium implantation

Abstract

We have used electrical measurements Deep level transient spectroscopy (DLTS) complemented by high-resolution X-ray diffraction (HRXRD) and Rutherford backscattering spectroscopy (RBS) measurements for assessment of the defects introduced in p-Si 1− x Ge x during 160 keV erbium ion implantation. From deep-level transient spectroscopy, it was observed that two prominent defects with discrete energy levels above the valence band, were introduced during Er ion implantation. The observed defects have similar signatures as those introduced during α-particle irradiation and electron beam metal deposition, indicating that these defects are more likely not related to Er but only to implantation induced damage such as primary defects. The generated defects expand the Si 1− x Ge x lattice in the implanted region, which results in the presence of the tail in the high-resolution X-ray diffraction spectra. After rapid thermal annealing (RTA) at 850 °C for 30 s in nitrogen ambient, a reduction in defect density as well as a relaxation of the Si 1− x Ge x lattice is observed for all x values. A dominant Er-related sharp emission in the 1.54 μm region was observed at room temperature and neither the intensity of the Er emission nor the emission peak position were influenced by the Ge content or the strain relaxation in the epilayers.