The defects which were introduced into 3C-type material, by 200keV N2+ or Al+ implantation, were detected by using a mono-energetic positron beam. The depth profiles of the defects were deduced from measurements of the Doppler broadening profiles of the annihilation radiation as a function of the incident positron energy. In the case of specimens which were implanted at substrate temperatures greater than 800C, the major defects were vacancy clusters. The depth profiles of vacancy-type defects were found to shift towards the specimen surface upon implantation at high temperatures. When furnace annealing was performed after implantation, the agglomeration of vacancy-type defects was observed, and interstitial clusters were introduced below the vacancy-rich region.

A.Uedono, H.Itoh, T.Ohshima, Y.Aoki, M.Yoshikawa, I.Nashiyama, H.Okumura, S.Yoshida, T.Moriya, T.Kawano, S.Tanigawa: Japanese Journal of Applied Physics, 1996, 35[1-12A], 5986-90