Dislocations and related traps in p-InGaAs/GaAs lattice-mismatched heterostructures

Dislocations and traps in p-InGaAs/GaAs lattice-mismatched heterostructures are investigated by cross-section transmission electron microscopy (XTEM) and deep level transient spectroscopy (DLTS). The misfit dislocations and threading dislocations observed by XTEM in different samples with different In mole fractions and different InGaAs layer thicknesses over all satisfy the Dodson–Tsao plastic flow critical layer thickness curve. By comparing the XTEM and DLTS results, we identify that the threading dislocations in bulk layers introduce three hole trap levels H1, H2, and H5 with DLTS activation energies of 0.32, 0.40, and 0.88 eV, respectively, and one electron trap level E1 with a DLTS activation energy of 0.54 eV. The misfit dislocations in the relaxed InGaAs/GaAs interface induce a hole trap level H4 with a DLTS activation energy of 0.67–0.73 eV.