Factors Influencing the Leakage Current in Embedded SiGe Source/Drain Junctions

This paper studies the leakage current components in embedded Si
_1-x
,Ge
_x
, source/drain (S/D) p
⁺
-n junctions, with different Ge contents, varying between 20% and 35%. In addition, the impact of performing a highly doped drain (HDD) implantation before or after the selective epitaxial deposition of in situ highly B-doped S/D layers is investigated. It is shown that the lowest junction leakage is obtained for the post-epi HDD condition, and moreover, for the smallest active area size. As pointed out, this dependence is related with a window-size-dependent strain relaxation, induced by the ion-implantation-related defects.