We apply X-ray multiple diffraction (XRMD) as a high resolution probe for analyzing the amorphous-crystal line interface (Si interstitial rich region) for different implantation energies and thermal treatment conditions during the formation of a shallow junction of B implanted in Si(001) crystals. Renninger scans (RS) (phi-scans) of the three sets of samples were measured using the (002) primary reflection, forbidden by the Si space group. Si(002) RS of as-implanted samples showed an extra peak conning from the Si interstitial atoms in the implanted region. This hybrid peak provides a very sensitive probe for analyzing the occurrence of interstitial Si atoms close to the amorphous-crystalline interface. We report its behavior as a function of the thermal treatment. The separation between the vacancy rich and the interstitial rich regions explains these results on the basis of the Si interstitial annihilation for shallow implantation. Samples with deep implantation are outside the detection range of the technique. in agreement with results for etched samples. (C) 2004 Elsevier B.V. All rights reserved.