Study of structural changes caused by nanosecond laser annealing of Ge- and Sn-implanted Si crystal

Abstract

Silicon single crystals were implanted with Ge or Sn ions and then annealed by nanosecond laser beam in a single-pulse mode. The structural changes caused by the laser annealing are studied by means of the Rutherford back-scattering and X-ray diffraction using the synchrotron radiation. In Ge-implanted Si samples in areas irradiated with a fluence below the threshold value of about 5% and with that near the threshold value of 40% of the total amount of the dopants introduced are located mainly in substitutional positions. For the Si implanted with Sn ions we observe the increase in the amount of interstitial dopants from 15% to 25% in regions annealed with the optimal fluence and with higher than that, respectively. The dependence of the lattice parameter on the laser fluence is studied. An increase in the lattice parameters for both implanted crystals in annealed regions is due to dopant ions expanding the elementary cell.