Analysis of the extended defects in 3C-SiC.pdf - Nelson Mandela ...

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left is that the line direction is of the type. The [100] makes an angle of 54.74°
with the [111] direction and if one infers the foil thickness from the projected
dislocation length, a thickness of ~280 nm is found. Thus it is possible that the
dislocation line direction is of the 100 type with the dislocation not running
completely from top to bottom in the foil but rather having been nucleated at a defect
somewhere within the foil. A possible nucleation point is shown on the micrograph in
Fig. 7.16. by the white arrow. Some form of residual contrast is visible which may
indicate a defect which acted as nucleation point.
Fig. 7.21. The simulated image of the dislocation indicated on Fig. 7.16.
None the less, the identification of the dislocation was done by simulation and the
results are shown in Fig. 7.21. Excellent agreement is seen but the true nature of the
defect will have to be established in a future study.
7.4 Reassessment of Unimplanted Sample
7.4.1 Overview of Investigation
The unimplanted SiC sample was investigated again, using a beam direction,
to determine whether similar dislocation complexes to those observed in the hydrogen
implanted SiC sample annealed at 1600°C was present. It was found that the same
dislocation structures are present in the unimplanted sample and it was concluded that
dislocation complexes was not introduced as a result of the irradiation or annealing
process.