Damage formation and annealing studies of low energy ion implants ...

R s (Ω/sq)
950
900
850
800
750
600°C anneal
sheet resistance
activated dose
0 20 40 60 80 100 120
anneal time (s)
6.3.2.2 Isochronal series
An isochronal anneal series was produced from the same wafer as the isothermal
series. Anneals for 10s duration were carried out at 600 °C, 650 °C and 700 °C. MEIS,
SIMS and Hall effect measurements were carried out on these samples with the same
conditions as used for the isothermal series. MEIS energy spectra are shown in Figure
6.15. Included in the figure is the random spectrum from an amorphous Si sample and
an as-implanted spectrum. Depth scales have been added to the figure for scattering off
As and Si. The differences in regrowth rates with temperatures are reflected in the level
of regrowth of these samples. The higher anneal temperatures with faster regrowth rates
have produced a much fuller regrowth. An interesting feature in the 700 °C sample is a
small bump in the Si background level at an energy of 76 keV, equivalent to a depth
beyond 12 nm, with the yield scale blown up in the inset. This may correspond to a
distortion of the Si lattice around defects in the EOR region. As with all samples the
shape of the As peaks is related to the depth of the regrown Si layer. The sample
annealed at 700 °C produces a quite well regrown layer, with a small segregated As
peak. In fact the spectrum from sample annealed at 700 °C for 10s is very similar to that
from the sample annealed at 600 °C for 120s.
146
2.2x10 21
2.0x10 21
1.8x10 21
1.6x10 21
Figure 6.14 Sheet resistance and activated dose for a 600 °C anneal with different
anneal durations.
activated dose (at/cm 3 )