A miniature electron-beam evaporator for an ultrahigh-vacuum atom-probe field-ion microscope

A miniature electron-beam evaporator (MEBE) has been fabricated and adapted to our ultrahigh-vacuum atom-probe field-ion microscope (APFIM). The MEBE allows for in situ vapor deposition-under ultrahigh-vacuum conditions (< 4 × 10^-10 Torr)-of a wide range of elements, on the surface of an atomically clean FIM specimen; the surface is prepared via the field-evaporation process. The deposition rate of an evaporant from the MEBE is calibrated to give an accurate value of this quantity. Examples of the deposition-at ≊0.3 nm min^-1- of silicon or titanium on tungsten FIM specimens are presented. And in the case of a Ti/W couple it is demonstrated that an interface between a tungsten substrate and a titanium overlayer is chemically sharp on an atomic scale; the titanium was vapor deposited at a substrate temperature of 77 K. Also a 20-kV electron-beam gun was adapted to our APFIM. This gun is useful for in situ electron-beam heating of bilayer couples, or the introduction of point defects in metal oxide or semiconductor overlayers via electronic mechanisms.