Investigation of the recombination activity of misfit dislocations in Si/SiGe epilayers by cathodoluminescence imaging and the electron beam induced current technique

Abstract

Misfit dislocations in as-grown and Ni-contaminated Si/SiGe epilayers have been characterized by cathodoluminescence (CL) spectroscopy, cathodoluminescence imaging, and the electron beam induced current technique (EBIC). Dislocations in the as-grown layers had no radiative recombination (D bands) and no detectable room temperature EBIC contrast. Following Ni contamination the D bands were observed and the EBIC contrast increased. CL dark line contrast is observed by monochromatic imaging of the Si substrate luminescence. The CL dark line contrast was observed from all the dislocations, whether contaminated or as grown. The CL dark line contrast and EBIC contrast show a 1:1 correspondence of the nonradiative recombination at the misfit dislocation and also a semiquantitative agreement with the variation in measured contrast of the individual dislocations.