Electron beam induced effects at silicon-transition metal silicide interfaces

Transition metal silicides were made by the vacuum thermal annealing of 20 nm metal layers on silicon substrates. The samples were then argon sputtered at 2 keV in a UHV Auger system till the silicide-silicon interface was reached. The interface was irradiated with electrons and the Auger spectrum recorded at regular time intervals. Metal atoms which had diffused into the silicon were found to be moving towards the surface under electron bombardment. A surface silicide layer 1–2 nm thick was formed by these migrating metal atoms. Pd, Pt and Cr silicides on (100) and (111) silicon surfaces were observed. The electron induced migration was much stronger for the Pd₂SiSi interface than for either the Pt₂SiSi or CrSi₂Si interface.