Study of oxygen incorporation in AlGaAs layers grown by molecular-beam epitaxy

Publisher Website
Google Scholar
Abstract
Quantitative measurements of oxygen content in epitaxial AlGaAs layers grown by molecular-beam epitaxy (MBE) are presented and compared with results on liquid phase (LPE) and metalorganic vapor phase epitaxy (MOVPE) layers. The analysis of oxygen concentration profiles measured on GaAs/AlGaAs or GaAs/AlAs multilayers shows that the oxygen incorporation in AlxGa1−xAs layers is arrival rate limited with a sticking coefficient essentially equal to one. The incorporation appears to proceed by a surface exchange reaction via an intermediate O-containing floating boundary layer. This interpretation is consistent with the experimental observations that the oxygen content of the MBE layers is independent of growth temperature between 600 and 700 °C, and that the oxygen level goes through a sharp maximum at the interface between a high Al and low Al content layers due to surface accumulation effects. Oxygen levels are found to be lower by a factor of 2 to 3 in multiquantum well (MQW) compared to random alloy layers of the same average Al content. Lowest 16O levels measured in ternary AlxGa1−xAs layers with 0.3<x<0.4 are around 4×1017 cm−3 for bulk MBE layers, around 1.2×1017 cm−3 for MBE MQW layers, and around (1.4–1.9)×1017 cm−3 for bulk layers grown by LPE and MOVPE.

This publication has 0 references indexed in Scilit: