Analysis of the extended defects in 3C-SiC.pdf - Nelson Mandela ...
Analysis of the extended defects in 3C-SiC.pdf - Nelson Mandela ...
Analysis of the extended defects in 3C-SiC.pdf - Nelson Mandela ...
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74<br />
The absence <strong>of</strong> an <strong>in</strong>termediate polycrystall<strong>in</strong>e layer along <strong>the</strong> <strong>in</strong>terface shows that <strong>the</strong><br />
growth did take place accord<strong>in</strong>g to a two-step process with an <strong>in</strong>itial carbonisation<br />
step achieved by only <strong>in</strong>troduc<strong>in</strong>g <strong>the</strong> propane.<br />
7.2.2 Stack<strong>in</strong>g Faults and Partial Dislocations<br />
Fig. 7.4. Bright field TEM micrographs taken from <strong>the</strong> bulk <strong>of</strong> <strong>the</strong> <strong>3C</strong>-<strong>SiC</strong> sample. B<br />
= [011], g =<br />
SF selected<br />
_<br />
11 1,<br />
s ≥ 0<br />
Fig. 7.4. shows a set <strong>of</strong> low magnification bright-field TEM micrographs <strong>of</strong> different<br />
areas <strong>in</strong> <strong>the</strong> <strong>3C</strong>-<strong>SiC</strong> representative <strong>of</strong> <strong>the</strong> bulk <strong>of</strong> <strong>the</strong> material. A high density <strong>of</strong><br />
stack<strong>in</strong>g faults (SF) are seen ly<strong>in</strong>g on <strong>the</strong> four {111} planes. Fr<strong>in</strong>ge contrast typical <strong>of</strong><br />
stack<strong>in</strong>g faults ly<strong>in</strong>g on <strong>in</strong>cl<strong>in</strong>ed and edge-on planes is seen. The stack<strong>in</strong>g faults are<br />
uniformly distributed throughout <strong>the</strong> foil.<br />
The prelim<strong>in</strong>ary results <strong>of</strong> tilt<strong>in</strong>g experiments <strong>in</strong> <strong>the</strong> electron microscope showed <strong>the</strong><br />
fault vector <strong>of</strong> <strong>the</strong> SF to be <strong>of</strong> <strong>the</strong> type 1/3 with bond<strong>in</strong>g partials <strong>of</strong> <strong>the</strong> type<br />
1/6 i.e. <strong>the</strong> partials are <strong>of</strong> <strong>the</strong> Shockley type. This <strong>in</strong>dicates that <strong>the</strong> fault was<br />
not formed as a result <strong>of</strong> <strong>the</strong> aggregation <strong>of</strong> po<strong>in</strong>t <strong>defects</strong>, which would form a Frank<br />
loop with Burgers vector <strong>of</strong> <strong>the</strong> type 1/3.