Simultaneous observation of the behavior of impurities and silicon atoms in silicon isotope superlattices

The behavior of impurity (arsenic or boron) and silicon host atoms during ion implantation was investigated using silicon isotope superlattices. The depth profiles of silicon isotopes in the ²⁸Si/³⁰Si isotope superlattices before and after ion implantation were obtained by secondary ion mass spectrometry. The experimentally determined profiles were reproduced very well by a theoretical model to yield the average displacement of silicon atoms as a function of the depth. The critical displacement of silicon to induce the amorphous layer was determined together with cross-sectional transmission electron microscopy.