This paper describes the impact of various defect types on the junction leakage in highly doped drain p+/n junctions, fabricated on strained silicon/relaxed silicon-germanium (SiGe) virtual substrates. The SiGe substrates were fabricated with a thin buffer-layer scheme, using a carbon-doped layer to induce a high relaxation degree of the virtual substrate. Threading dislocations, carbon-induced defects, and residual implantation damage each have a distinct effect on the junction leakage, generation lifetime, and high-temperature behavior of the diodes. It is shown that threading dislocations degrade the junction quality at room temperature. However, the high-temperature behavior of these junctions is diffusion-dominated. When present in the depletion region, carbon-induced defects cause a large generation current inside the SiGe diodes, a behavior that is dominant in the full temperature range investigated (20 degrees C < T-measure < 250 degrees C). Implantation damage influences the leakage in silicon junctions but is of minor importance in SiGe junctions with a large amount of threading dislocations or carbon-induced defects. While increasing the thermal anneal budget has a large relative influence on the silicon junctions, this effect is less pronounced for the SiGe junctions, showing that defects associated with threading dislocations or carbon-induced defects are not as easily removed as damage resulting from the n-well implantation. (c) 2006 The Electrochemical Society.