Detection of misfit dislocations at interface of strained Si/Si0.8Ge0.2 by electron-beam-induced current technique

Abstract

Electron-beam-induced current (EBIC) has been employed to investigate misfit dislocations (MDs) at the interface of strained Si/Si0.8Ge0.2, which are located within the depletion region of Schottky contact. The MDs are intentionally introduced by growing the strained-Si layer to a thickness larger than the critical thickness. Two orthogonal sets of weak dark lines and some weak dark dots are observed with low electron-beam energy at a low temperature. These dark lines and dark dots correspond to the MDs and threading dislocations (TDs), respectively. The MDs and TDs are found to be nearly electrically inactive at room temperature and increase their activities at lower temperature, indicating that they are accompanied by shallow levels and free from metallic contamination. Comparisons with the chemical etched pattern reveal that each of the EBIC dark lines corresponds to a bundle of MDs.