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Epitaxial layers are crucial for semiconductor technology. |
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Misfit of lattice constants will produce strained layers upon epitaxial growth;
strain relief happens by the formation of misfit dislocations. | |
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Misfit dislocatipons must be avoided at all costs! |
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Below a usually rather small critical thickness dcrit of the the
thin layer no misfit dislocations will occur. | |
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Rule of thumb:
0.5 % misfit Þ dcrit
»10 nm | |
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The internal structure of thin films can be anything known from bulk materials
plus some (important!) specialities. | |
a-Si: Micro electronics
a-Si:H: Solar cells, LCD displays
µc-Si:H: Solar cells |
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Properties of thin films can be quite different from that of the bulk material |
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Much better in thin films
- Electrical break-down field strength of dielectrics.
- Critical current densities in conductors.
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The reason can be differences in length scales. |
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Semiconductor technology relies to some extent on superior thin film properties |
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© H. Föll (Semiconductor Technology - Script)
