The puzzler answers - atom! By balancing line force...

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The puzzler answers Nov 1 st , 2011
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Stress applied Dislocation sort themselves out, get “stuck” in twin boundaries
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Forming twin boundaries with superimposed small angle grain boundaries
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TEM measures tilt angle which gives dislocation content of original grain
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When the twin boundary has “collected” a critical number of dislocations, a small angle grain boundary will split of the twin boundary, and the boundary will return to the coherent twin formation
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The next puzzler Spiral Dislocation
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The spiral, in extremis, is, hold on, a Frank loop!
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The Frank Dislocation loop
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Which means we can determine the number of point defects (number of missing atoms) by measuring the area and divide it by area of an
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Unformatted text preview: atom! By balancing line force (increase in dislocation length due to spiral) versus number of point defects stored, we can measure the super saturation ratio of point defects. If we are good at TEM, we can decide if we store vacancies or interstitials (curvature of lattice The point defects explains why the diffusion profile of P in Silicon is by now means The diffusion in Si is very complex, as e.g. the vacancy appears in four flavors Neutral Single positive Single negative Double negative Each of which has its own diffusion parameters and the concentration of which (except the neutral) depends on the Fermi level (which in turn changes with the doping profile)...
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The puzzler answers - atom! By balancing line force...

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