High-pressure-induced defect formation in silicon single crystals II. Mechanism of stress-field formation at precipitates

Abstract

A mechanism is proposed for the generation of defects characterized by a line of 'no X-ray contrast' perpendicular to the diffraction vector g in silicon single crystals subjected to high pressure and temperature. It is shown that the formation of a stress field at second-phase precipitates embedded in the silicon matrix caused by a difference in the compressibilities and thermal expansion coefficients is the reason for defect creation. Using the idea of a critical misfit between the precipitate and the matrix needed for the generation of interface dislocations, the composition and structure of the precipitates are determined to be those of amorphous silicon dioxide. Expressions are obtained which enable the stress relaxation at precipitates at high pressure and temperature to be calculated.