  Atom probe tomography requires needle-shaped specimens with a diameter
typically below 100 nm, making them both very fragile and reactive, and defects
(notches at grain boundaries or precipitates) are known to affect the yield and
data quality. The use of a conformal coating directly on the sharpened specimen
has been proposed to increase yield and reduce background. However, to date,
these coatings have been applied ex-situ and mostly are not uniformly. Here, we
report on the controlled focused ion beam in-situ deposition of a thin metal
film on specimens immediately after specimen preparation. Different metallic
targets e.g. Cr were attached to a micromanipulator via a conventional lift-out
method and sputtered using the Ga or Xe ions. We showcase the many advantages
of coating specimens from metallic to non-metallic materials. We have
identified an increase in data quality and yield, an improvement of the mass
resolution, as well as an increase in the effective field-of-view enabling
visualization of the entire original specimen, including the complete surface
oxide layer. The ease of implementation of the approach makes it very
attractive for generalizing its use across a very wide range of atom probe
analyses.
