STRAIN-INDUCED SELF ASSEMBLING OF NANOVOIDS IN Si/SiGe MULTI-LAYER STRUCTURES

摘要

We report on self-assembled formation of spherically shaped voids in MBE grown SiGe alloy layers implanted in-situ at elevated temperature with low-energy Ge ions, followed by thermal annealing. The voids are of nanometer size and are e xclusively assembled in thin SiGe quantum wells. The voids only appear in the layers after heat treatment at a temperature higher than 700℃, and they are stable up to 950℃. The results are discussed in terms of the separation of the vacancies and interstitials induced by the strain situation around the SiGe quantum wells.