Compositional analysis of interfaces in semiconductor materials grown
with the most modern equipment requires a substantial improvement of t
he depth resolution of secondary ion mass spectrometry (SIMS). The low
ering of the impact energy to improve depth resolution is limited on m
ost magnetic-sector instruments to similar to 1.5 keV. In this work it
is shown that in the VG IX70S magnetic-sector instrument a reduction
of the impact energy to 600 eV is possible. The reduction is achieved
by use of a deceleration electrode in the primary beam line, allowing
for independent variation of the energy and the incidence angle theta
(50 degrees<theta<80 degrees). The best depth resolution obtained-for
a shallow Ge delta layer with a 600 eV theta=80 degrees O-2(+) beam-wa
s 1.6 nm full width at half-maximum and an exponential decay length of
0.65 nm; about three times better than achievable on any other magnet
ic-sector SIMS instrument. In addition, a very shallow (similar to 3-4
nm) Ge delta layer has been analyzed by high-resolution Rutherford ba
ckscattering and SIMS. There is good agreement between both techniques
. (C) 1998 American Vacuum Society.