Evolution of real structure in Ge‐Si mosaic crystals

Abstract

The structure and properties of Czochralski (Cz)-grown Ge 1-x Si x mosaic crystals were investigated using optical microscopy, atomic force microscopy, X-ray diffraction analysis, microprobe analysis, FTIR and transmission electron microscopy. The role of segregation, form of solidliquid interface and dislocation generation in the development of mosaic structure were analyzed and used for optimization of growth parameters such as Si concentration and growth rate. The dislocation density estimated experimentally was compared with the calculated data. Composition fluctuations caused by formation of cellular structure at the interface lead to a local lattice misorientation that is one of the reasons for crystal mosaicity. Model of mosaic structure generation in terms of dislocation density and composition variations is presented.