Mechanisms in the Ion-Assisted Etching of TiSi2

Abstract

ABSTRACTA detailed investigation into the mechanisms of the ion-assisted etching of TiSi2 using 1000 eV argon ions and chlorine gas is reported. X-ray photoelectron spectroscopy (XPS) was used to investigate surface product distributions and modulated ion beam mass spectroscopy (MIBMS) was used to investigate gas phase product distributions. Identical experiments were performed on silicon and titanium single crystal substrates. Information on chemical mechanisms during ion-assisted etching was obtained by comparing the product distributions of the three substrates. For each substrate, the di and tetrachlorides were the major gas phase products. These products were emitted with high thermal velocities following a surface residence process. TiCl and TiCl2 products were found on the titanium surface after simultaneous exposure to chlorine and argon ions, but not on the TiSi2 surface. These observations are discussed in terms of specific chemical mechanisms which are critical during ion-assisted etching.