Threading dislocation reduction mechanisms in low-temperature-grown GaAs

1089-7550

AIP Digital Archive

Physics

In these studies, we have investigated the role of low-temperature growth in the reduction of threading dislocation (TD) densities in large mismatch heteroepitaxy. Low- and high-temperature (LT) and (HT) GaAs growths on highly mismatched substrates were used to find the mechanism of enhanced TD reduction in LT grown (250 °C) GaAs. LT templates have symmetric (equal) TD subdensities on the {111}A and {111}B planes, whereas HT templates have asymmetric TD subdensities. A model based on TD reactions was applied to the experimental results and confirmed the beneficial role of symmetric TD subdensities in LT GaAs TD reduction. A ductile-to-brittle transition in dislocation behavior was observed at ∼400 °C. © 1999 American Institute of Physics.

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