X-ray Diffraction Investigations of Structure of Silicon Single Crystals after Irradiation by Heavy Ions

Abstract

Structure distortions appearing near the surfaces of crystals irradiated by high energy ions (H, Kr, U) accelerated till energy of several MeV using respectively the accelerator U-120 (Kiev, Ukraine), the heavy ions accelerators (Caen, France and Darmstadt, Germany) were investigated by means of various X-ray diffraction methods (topography and diffractometry). Nonhomogeneous distribution of lattice distortions near the surfaces of irradiated crystals were discovered using these methods in all of the samples. Besides the barrier zones where the accelerated ions stopped, the wide distorted regions situated nearer the surface were found. The fine structure of different zones, their extents as well as the level of static Debye-Waller factor were determined. The depth distribution of this factor was compared with the results obtained by using the edge contrast measurements some years ago. This permitted us to draw conclusions about some relaxation of elastic strains in the interference regions after many years.

Structure Changes in Cz-Si Single Crystals Irradiated with Fast Oxygen and Neon Ions

“…2, performed basing on the interpretations given in papers [8][9][10] indicates for the larger variation of the shape of the curve after irradiation with neon ions. The diffraction effects (flash-up of intensity) from the amorphous layers are pointed out by the arrows on the curves for the both implanted samples.…”

“…The curves of spatial distribution of X-ray intensity were registered at the fixed Bragg position of the sample with narrow (≈ 50 pm) slits situated near the moving detector. This method permits to separate from the recorded intensity the contribution of diffuse scattered intensity IDs due to defects localized at various depths as well as elastic strains [8][9][10]. Hówever, the inhomogeneous distribution of defects along the normal to the surface does not allow to determine some average structural characteristics of the layers situated at the absorption depth t o = p -1 , where p is the photoelectric coefficient of absorption.…”

Synchrotron White Beam Topographic Studies of Gallium Arsenide Crystals

“…It was recently shown [4,5] that using more sensitive reflections of shorter wavelength and high indices results in improved detection of small inclusions and other microdefects. This may be easily realized with the use of synchrotron radiation providing a free choice of radiation wavelength and reflections and a better spatial resolution.…”