Characterization of InP/GaAs/Si structures grown by atmospheric pressure metalorganic chemical vapor deposition

Abstract

The thickness dependence of material quality of InP-GaAs-Si structures grown by atmospheric pressure metalorganic chemical vapor deposition was investigated. The InP thickness was varied from 1–4 μm, and that of the GaAs from 0.1–4 μm. For a given thickness of InP, its ion channeling yield and x-ray peak width were essentially independent of the GaAs layer thickness. The InP x-ray peak widths were typically 400–440 arcsec for 4-μm-thick layers grown on GaAs. The GaAs x-ray widths in turn varied from 320–1000 arcsec for layer thicknesses from 0.1–4 μm. Cross-sectional transmission electron microscopy showed high defect densities at both the InP-GaAs and GaAs-Si interfaces. In 4-μm-thick InP layers the average threading dislocation density was in the range (3–8)×108 cm−2 with a stacking fault density within the range (0.4–2)×108 cm2. The He+ ion channeling yield near the InP surface was similar to that of bulk InP (χmin∼4%), but rose rapidly toward the InP-GaAs heterointerface where it was typically around 50% for 1-μm-thick InP layers. All samples showed room-temperature luminescence, while at 4.4 K, exciton-related transitions, whose intensity was a function of the InP thickness, were observed.