Trace determination of iron on a silicon wafer surface by silicon direct bonding and neutron activation analysis

In order to determine iron on silicon wafer surface at a level of 1014 atoms·m−2 the efficiency of a well-type Ge detector for59Fe γ-ray emissions was measured and a low temperature silicon direct bonding technique was developed. With silicon direct bonding at a temperature of 350 to 650°C iron remains near the interface of the bound silicon. The iron contamination of the interface escaped from the interface can be ignored with this technique. The value of iron obtained was (2.7 to 5.9)·1014 atoms · m−2 in the surface on silicon wafers.