Excess As in low‐temperature grown InAs

Using secondary ion mass spectrometry, we have investigated the excess As concentration in InAs layers grown by molecular beam epitaxy at 150‐300 °C. A step‐like increase of the As/In ratio from the substrate to the epi layer was observed for the samples grown at lower temperatures than 250 °C. The excess As concentration averaged over the grown layer thickness reached 1.2×1020 cm–3 for the layer grown at 200 °C. Through the combination with the results of X‐ray diffraction, a proportional relation of Δa⊥/a = 2×10–24 δ [As] is deduced between the perpendicular lattice mismatch Δa⊥/a and the atomic density δ [As] of excess As in the unit of cm–3. Hall effect measurements at 77 K revealed that the electron concentration is much lower than the excess As concentration. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)