Simulation of images of spherical strain centres in X-ray section topographs

Abstract

X-ray section topograph images of spherical strain centres in elastically isotropic crystals have been simulated using numerical solution of Takagi's equations. Variations in the image with the size of the deformation strain field, the defect position in the Borrmann fan and the crystal thickness have.. been investigated. Excellent agreement has been found between the simulated images and a wide variety of experimental images from hydrogen-induced strain centres in float-zone silicon.

X-ray topography studies of microdefects in silicon

“…Analysis of the results of section topography experiments can be supported by computersimulated images of relevant defects, thus enabling a detailed examination of all important parameters (fault vectors, strain fields, etc.). For example, such studies for oxygen-related microdefects and precipitates in silicon were done by Patel & Authier (1975), Green et al . (1990), Holland et al .…”

“…Very small microdefects (on the verge of detectability on X-ray topographs) give only simple direct contrast, without any fine structure. The image of spherical microdefects when fully developed (usually for diameters of the order of several tenths of a µm) consists of direct contrast (black head), dynamic contrast (white tail) with fine structure due to intermediary contrast ( Green et al . 1990;Holland & Tanner 1995).…”

“…1990;Holland & Tanner 1995). The specific features of this contrast depend on the physical parameters characterizing the defect, such as the fault vector, the magnitude and sign of the strain field, as well as the geometry of the defect and its position inside the Borrmann triangle (Green et al . 1990;Holland & Tanner 1995).…”

“…1994;Lefeld-Sosnowska 1985;Lefeld-Sosnowska et al . 1988, 1996aLefeld-Sosnowska & Gronkowski 1989;Green et al . 1990;Holland et al .…”