A study on secondary defects in self-ion implanted Si

Abstract

By using the cross-sectional transmission electron microscopy (XTEM), Rutherford backscattering (and channeling) spectrometry (RBS) and high-energy electron beam irradiation technology with a high voltage electron microscope (HVEM), secondary defects in self-ion implanted Si has been studied. The result shows that the depths of secondary defect bands are related to the implantation energies, and the values of depths are slightly greater than the projected ranges of self-ions implanted into Si. In the higher energy region (>1 MeV), the former exceeds the latter by nearly 0.2-0.4 μm. Experiments indicate that the pre-implantation damage (the primary defect), on one hand, will superpose on the primary defects of post-implantations and make secondary defects increase, and on the other hand, it will also provide an enhanced-diffusion region for vacancies and interstitials created by the post-implantation and reduce the formation of secondary defects. Experiments also show that dislocation loops in secondary defect bands of self-implanted Si are interstitial in nature.