The
influence of the flooding gas during ToF-SIMS depth profiling
was studied to reduce the matrix effect and improve the quality of
the depth profiles. The profiles were measured on three multilayered
samples prepared by PVD. They were composed of metal, metal oxide,
and alloy layers. Dual-beam depth profiling was performed with 1 keV
Cs
+
and 1 keV O
2
+
sputter beams and
analyzed with a Bi
+
primary beam. The novelty of this work
was the application of H
2
, C
2
H
2
,
CO, and O
2
atmospheres during SIMS depth profiling. Negative
cluster secondary ions, formed from sputtered metals/metal oxides
and the flooding gases, were analyzed. A systematic comparison and
evaluation of the ToF-SIMS depth profiles were performed regarding
the matrix effect, ionization probability, chemical sensitivity, sputtering
rate, and depth resolution. We found that depth profiling in the C
2
H
2
, CO, and O
2
atmospheres has some
advantages over UHV depth profiling, but it still lacks some of the
information needed for an unambiguous determination of multilayered
structures. The ToF-SIMS depth profiles were significantly improved
during H
2
flooding in terms of matrix-effect reduction.
The structures of all the samples were clearly resolved while measuring
the intensity of the M
n
H
m
–
, M
n
O
m
–
, M
n
O
m
H
–
, and M
n
–
cluster secondary ions. A further
decrease in the matrix effect was obtained by normalization of the
measured signals. The use of H
2
is proposed for the depth
profiling of metal/metal oxide multilayers and alloys.