X-RAY-DIFFRACTION INVESTIGATIONS OF STRUCTURE OF SILICON SINGLE-CRYSTALS AFTER IRRADIATION BY HEAVY-IONS

Structure distortions appearing near tile surfaces of crystals irradia ted by high energy ions (H, Kr, U) accelerated till energy of several MeV using respectively the accelerator U-120 (Kiev, Ukraine), the heav y ions accelerators (Caen, France and Darmstadt, Germany) were investi gated by means of various X-ray diffraction methods (topography and di ffractometry). Nonhomogeneous distribution of lattice distortions near the surfaces of irradiated crystals were discovered using these metho ds in all of the samples. Besides the barrier zones where the accelera ted ions stopped, tile wide distorted regions situated nearer the surf ace were found. Tile fine structure of different zones, their extents as well as the level of static Debye-Waller factor were determined. Th e depth distribution of this factor was compared with the results obta ined by using the edge contrast measurements some years ago. This perm itted us to draw conclusions about some relaxation of elastic strains in the interference regions after many years.