The Nature of Thermally Induced Stresses in Silicon and Their Relation to Observed X-Ray Diffraction and Birefringence Phenomena

Abstract

The purpose of this paper is to describe qualitatively the residual stress field induced in single-crystal silicon by electron-beam melting and subsequent resolidification in microspot areas. The stress distribution is derived by vector relationship from previously reported experimental observations by x-ray topography and polarized ir radiation techniques. The stresses are distributed in a sixfold pseudohyperbolic form around the microspots. This distribution correlates with the four-lobed x-ray rosettes recorded from various x-ray reflections. The stresses are concentrated normal to the {111} planes of the parent lattice and, in projection, all stresses in the 〈110〉 directions are tangential to the microspot. Infrared birefringence results from stresses along the 〈111〉 directions either within the microspot or at its interface with the parent lattice. These directions thus become uniaxial optic axes coincident with the stress direction. Recrystallization mechanisms are discussed in relation to the macro stacking fault observed by x-ray topography.