Transmission Electron Microscopy Observation of Defects Induced by Fe Contamination on Si(100) Surface

Abstract

The behavior of Si(100) surface defects induced by Fe contamination was studied with transmission electron microscopy. After annealing at 1150°C for 1 hour and a subsequent heat treatment at 850°C for 2 hours, Fe-containing precipitates were observed in Si substrate in close vicinity to the interface of Si and SiO 2 formed during the annealing. One of these precipitates is identified as FeSi-type silicide. In addition, the inclusions which were confirmed to be Fe 3 O 4 or γ-Fe 2 SiO 4 were observed in the surface thermal SiO 2 layer. These results demonstrate that Fe atoms diffuse into the Si substrate during annealing at 1150°C and precipitate at a Si/SiO 2 interface, while Fe atoms left on the surface form inclusions in the surface SiO 2 layer. Under an additional thermal oxidation at 1000°C, oxidation-induced stacking faults were formed. They were not decorated at all in contrast with those induced by Cu or Ni contamination.