Page 220 - Inorganic Mass Spectrometry - Fundamentals and Applications

205

i

21
21

20

-.
0 5 10 15 20

Figure 36 Comparison of normal incidence profiling in vacuum to 60" incident profil-
ing with oxygen flooding. Profiles of boron implanted in silicon. (From Ref. 122.)

for continuous correction of the depth and concentration scale based on knowledge
of the matrix sputter yield and relative sensitivity factor [RSF ( llB, 3oSi)]. These
the
authors also used SF,+ sputtering to provide the smallest transient depth. The large
six-atom ion implantation is very shallow as a result of ~agmentation that reduces
the effective energy of the beam.
Magee et al. [ l251 used O,+ with a quadrupole SIMS to profile an epitaxial
silicon grown with five boron delta-doped layers, each 5.4 nm thick. Bomb~dment
energies from 400 eV to 1.5 keV were used with angles of incidence from 0" to
70". Analyses were performed with and without oxygen flooding. With a sputter-
ing energy of 500 eV (at 50" incidence, and oxygen flooding), no measurable
change in sputtering rate was found in the transient region or between any of the
layers. A similar sample was profiled in a magnetic sector instrument, using O,+
with l keV, at 56" incidence, and oxygen flooding [126]. There was a small 0.6-