EY-EXAFS and Mössbauer spectroscopy of the Au/Si interface

The Au-Si interface [1] plays a significant role in high speed VLSI electronic devices. However, the structure of this interface and particularly the formation and properties of gold silicides are not yet well established. In this work thin (3–50 μm/cm2) gold layers deposited on or implanted in (at doses from 1015 up to 7×1016/cm2) Si(111) single crytals, as well as gold diffused into Si through thermal or laser annealing, have been studied by Au L3 EXAFS with electron-yield detection (EY-EXAFS), and by conversion electron Mossbauer spectroscopy (CEMS) of the 77.3 γ-rays in 197Au. EY-EXAFS and CEMS probe local structure in a complementary fashion with depth sensitivities which are similar to the depth of diffused and ion implanted interfaces. Thus the combination of these tecniques is particularly useful for studies of implanted and deposited thin films.