BRAGG-CASE SYNCHROTRON SECTION TOPOGRAPHY OF SILICON IMPLANTED WITH HIGH-ENERGY PROTONS AND ALPHA-PARTICLES

Back-reflection section topography using white-beam synchrotron radiat ion has been applied for the investigation of silicon implanted with 1 and 1.6 MeV protons and 4.8 MeV alpha particles. The beam width was l imited to 5 mu m, and a series of spots in the vicinity of a centrally adjusted reflection were indexed and analysed. The back-reflection se ction pattern of implanted crystals usually exhibits fringes correspon ding to the reflection from the surface and a series of fringes corres ponding to the rear region of the shot-through layer, the destroyed la yer and the bulk. The patterns were used for direct evaluation of ion ranges and thicknesses of the shot-through layer. The overall characte ristics of the obtained patterns were successfully reproduced in simul ations based on numerical integration of the Takagi-Taupin equations. The agreement between the simulation and experiment proves that the la ttice-parameter depth-distribution profiles can be assumed to be propo rtional to interstitial-vacancy distributions obtained using the Monte Carlo method from the Biersack-Ziegler theory. The simulation also re produced interference tails observed in some section patterns. It was found that these tails are caused by the ion-dose change along the bea m and they were probably formed due to the interference between the ra diation reflected from the bulk and those rays reflected by the rear r egion of the shot-through layer.