Tellurium nanoclusters were synthesized in (100) Si by ion implantation followed by annealing for 60 min with a 0.45 MHz high-frequency electromagnetic field. The results were compared with previous ones for a 30 min treatment. Structural studies were done by cross-sectional high resolution transmission electron microscopy and fast Fourier transformation of the images. The results show that for the 60 min treatment, the dynamics of nanocluster formation change, larger clusters are observed, some of which crystallized and were separated by high-resistive areas of amorphous Si. The structural changes are correlated with the electrical resistance as measured by ac impedance spectroscopy. The conductance of the samples after the 60 min treatment, compared to as implanted samples, dropped by seven orders of magnitude in the range of low frequencies and about three orders of magnitude at higher frequencies. This drastic change of the electrophysical behaviour of the field treated nanomaterial is discussed in terms of potential barriers at the interface of different phases.