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1992
Conference Paper
Titel
Differences in the growth mechanism of InxGa1-xAs on GaAs studied by the electrical properties of Al0.3Ga0.7As/InxGa1-xAs heterostructures 0.2 equal/smaller than x equal/smaller than 0.4
Alternative
Unterschiede im Wachstumsmechanismus von InGaAs auf GaAs untersucht mittels elektrischer Eigenschaften von AlGaAs/InGaAs-Heterostrukturen 0.2 kleiner/gleich x kleiner/gleich 0.4
Abstract
Lattice mismatched InsubxGasub1minusxAs layers with InAs mole fractions below 0.25 grow in a two dimensional growth mode on GaAs. If the thickness of these layers is beyond the critical layer thickness the strain relaxes through misfit dislocations. The misfit dislocation density in the (011) and (01-1) direction differs for n-type layers. This results in a highly anisotropic electron mobility for GaAs/InsubxGasub1minusxAs/Alsub0.3Gasub0.7As inverted HEMT structures. A higher electron mobility in the (011) direction is measured in comparison to the (01-1) direction. The resistance ratio in the two perpendicular directions exceeds 10high5. For a three dimensional growth mode, the InsubxGasub1minusxAs layer shows interface roughness which degrades the transport properties of the normal Alsub0.3Gasub0.7As/ InsubxGasub1minusxAs/GaAs HEMT structures more than the inverted GaAs/InsubxGasub1minusxAs/ Alsub0.3Gasub0.7As HEMT structures. For a three dimensional growth mode, an anisotropic elect ron mobility for Alsub0.3Gasub0.7As/InsubxGasub1minusxAs/GaAs HEMT structures is also observed. For these structures the highest electron mobility is measured in the (01-1) direction. This anisotropy could be explained by anisotropic growth rates in the (011) and (01-1) directions which results in growth islands with asymmetric extensions.
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