As complementary metal-oxide-semiconductor (CMOS) devices approach the sub-100-nm dimensions in accordance with Moore's Law, several major technical barriers exist with the formation of ultrashallow junctions. Strained silicon CMOS devices have the advantages of higher carrier mobility and high current drive. The use of silicon germanium substrates for strain in the silicon channel presents many challenges for CMOS integration including maintaining the channel strain and effect on shallow source/drain (SD) junctions. Low energy secondary ion mass spectrometry (SIMS) has been used to study boron and arsenic diffusion behavior in strained silicon and in SiGe. In addition, diffusion of germanium from the relaxed SiGe into the strained silicon layer will be discussed in relationship with SD implant and annealing. SIMS experimental results will also be compared to theoretical simulation results. (C) 2004 American Vacuum Society.