The formation of secondary radiation defects, in crystals which were subjected to low doses of photon-assisted ion implantation, was investigated by means of deep-level transient spectroscopy. Approximately equal amounts of primary radiation defects, having similar spatial profiles, were introduced into n-type and p-type samples by the low-dose (1011/cm3) implantation of O, N or Ar ions under varying temperature and photo-excitation conditions. An analysis of the resultant deep level transient spectra revealed significant differences in the defect formation process as well as in the nature of the defects which were generated in n-type and p-type samples. These observations revealed a qualitative difference in the defects which were formed in n-type and p-type material. The defects which were identified in n-type samples were mainly divacancy complexes, whereas 2 other types of competing defect were formed in p-type material. Each of them had a different optimum formation temperature. Low implantation temperatures and low power-density photo-excitation of n-type crystals stimulated the formation of divacancies. The same experimental conditions caused suppression rather than promotion of overall defect formation in p-type crystals. However, at a high power density, photo-excitation activated the formation of defects in both types of sample. The efficiency of photo-excitation defect formation was temperature-dependent in both n-type and p-type material. The dependence was direct in the former, and reverse in the latter. The role of photon assistance in the process of defect formation in n-type material was shown to be affected by the mass of the implanted ions. The effect of photo-excitation was clear in the case of light ions, and tended to decrease in the case of heavy ions.

The Influence of Target Temperature and Photon Assistance on Radiation Defect Formation in Low-Fluence Ion-Implanted Silicon. M.Y.Barabanenkov, J.Gyulai, A.V.Leonov, V.N.Mordkovich, N.M.Omelyanovskaya, H.Ryssel: Nuclear Instruments & Methods in Physics Research B, 2001, 174[3], 304-10