DEPTH PROFILING OF VACANCY CLUSTERS IN MEV-IMPLANTED SI USING AU LABELING

A technique for profiling the clustered-vacancy region produced by hig h-energy ion implantation into silicon is described and tested. This t echnique takes advantage of the fact that metal impurities, such as Au , are trapped in the region of excess vacancies produced by MeV Si imp lants into silicon. In this work, the clustered-vacancy regions produc ed by 1-, 2-, and 8- MeV Si implants into silicon have been labeled wi th Au diffused in from the front surface at 750 degrees C. The trapped Au was profiled with Rutherford backscattering spectrometry. The dyna mics of the clustered-vacancy region were monitored for isochronal ann ealing at 750-1000 degrees C, and for isothermal annealing at 950 degr ees C, for 10-600 s. Cross-sectional transmission electron microscopy analysis revealed that after the drive-in anneal, the Au in the region of vacancy clusters is in the form of precipitates. The results demon strate that the Au-labeling technique offers a convenient and potentia lly quantitative tool for depth profiling vacancies in clusters. (C) 1 998 American Institute of Physics. [S0003-6951(98)05046-3].