Strain‐Driven Self‐Assembling of Nano‐Voids and Formation of Core–Shell Bubbles in SiSn/Si Layers

Abstract

Self‐assembling of nanometer size voids in strained Sn precipitates after hot He+ ion implantation is investigated by transmission electron microscopy (TEM). It is deduced from TEM study that high‐temperature irradiation produces vacancies which is collected by compressively strained Sn precipitates enhancing out‐diffusion of Sn atoms from the precipitates. The effects of implantation dose and Sn precipitate size on void formation and Sn out‐diffusion are documented and evolution of voids into core–shell Sn‐bubbles is reported. In particular, the size of the voids increased with the implantation dose and the voids are transformed to the core–shell Sn particles after implantation of 6 × 1015 He+ cm−2. Formation of the core–shell structures is faster for Sn particles of smaller initial size. Strain‐enhanced separation of point defects along with vacancy‐assisted Sn out‐diffusion and precipitate dissolution are discussed.