Compound formation and bonding configuration at the Si-Cu interface

Abstract

Joint photoemission and Auger $\mathrm{LVV}$ line-shape spectroscopies on the Si-Cu interface show the existence of a silicidelike compound with bonding characteristics similar to those of the near-noble-metal silicides. This makes the Si-Cu interface different from the other noble-metal-Si interfaces where alloylike phases (Si-Au) or narrow interfaces with concentration gradients (Si-Ag) are formed. The Si-Cu compound is metal-rich with a stoichiometry close to the eutectic composition ${\mathrm{Cu}}_3$Si and is stable over a wide range of temperatures.