ISSN:
1089-7550
Quelle:
AIP Digital Archive
Thema:
Physik
Notizen:
Threading dislocation morphologies and characteristics, as well as their generation conditions in InxGa1−xAs films grown by molecular beam epitaxy on GaAs (001) substrates have been investigated, mainly using cross-sectional transmission electron microscopy. The 3-μm-thick InxGa1−xAs films are mostly examined for x ranging over x=0.01, 0.05, 0.1, 0.15, 0.2, 0.3, and 0.5. Moreover, for x=0.2, epitaxial layers having film thicknesses of 0.5, 1, and 2 μm are investigated. The formation of a high density of threading dislocations which reach the film surface is detected in epilayers of x≥0.2 at a fixed film thickness of 3 μm and with film thicknesses greater than 2 μm at x=0.2. In layers of x≤0.15, such threading dislocations are rarely detected, although dislocation segments on the {111} planes threading into the upper regions from the interface are frequently observed. Most of the observed threading dislocations are 60° and pure-edge type dislocations along the 〈211(approximately-greater-than) and 〈110(approximately-greater-than), and [001] directions, respectively. The former type dislocations are mainly observed in layers of x≤0.15; the latter predominantly exist in layers of x≥0.3. In epilayers of x=0.2, the two types of threading dislocations mentioned above coexist. It is also discussed that the formation of the above-mentioned threading dislocations is strongly associated with misfit dislocations which are introduced in the InxGa1−xAs layers under the different growth modes, depending on x.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1063/1.351411
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