Dislocation effects on carrier concentration for molecular-beam-epitaxially grown GaAs

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Abstract
Dislocation effects on carrier concentration for Si‐doped and Si‐implanted molecular‐beam‐epitaxially (MBE) grown GaAs layers are investigated by small area (40×40 μm2) Hall measurements. It is found that there is no correlation of carrier concentration with dislocation density and distance from a dislocation to a Hall device. The photoluminescence 1.51‐eV bound exiton peak and the 1.49‐eV carbon acceptor peak intensity variations are small across a wafer. Moreover, there are no variations in high‐resolution photoluminescence intensity and in electron‐beam‐induced current image between positions close to and far from a dislocation. These results indicate that carrier concentration is not affected by dislocations in MBE‐grown epilayers because of the absence of a denuded zone around the dislocation. Acceptors and/or point defects are depleted in liquid‐encapsulated Czochralski‐grown GaAs, whereas this does not take place during the MBE growth processes.