Bandlike and localized states of extended defects in n-type In_(0.53)Ga_(0.47)As

摘要

In0.53Ga0.47As p + n diodes with different densities of extended defects have been analyzed by detailed structural and electrical characterization. The defects have been introduced during Metal-Organic Vapor Phase Epitaxy (MOVPE) growth by using a lattice-mismatched layer on a semi-insulating InP or GaAs substrate. The residual strain and indium content in the n-type In0.53Ga0.47As layer have been determined by high-resolution X-ray diffraction, showing nearly zero strain and a fixed indium ratio of 0.53. The deep levels in the layer have been characterized by Deep Level Transient Spectroscopy. The mean value of electron traps at 0.17 +/- 0.03 eV below the conduction band minimum E-C is assigned to the "localized" states of alpha 60 degrees misfit dislocations; another broad electron trap with mean activation energies between E-C-0.17 +/- 0.01 and 0.39 +/- 0.04 eV, is identified as threading dislocation segments with "band-like" states. A high variation of the pre-exponential factor K-T by 7 orders of magnitude is found for the latter when changing the filling pulse time, which can be explained by the coexistence of acceptor-like and donor-like states in the core of split dislocations in III-V materials. Furthermore, two hole traps at E-V + 0.42 +/- 0.01 and E-V + 0.26 +/- 0.13 eV are related to the double acceptor of the Ga(In) vacancy (V-Ga/In(3-/2-)) and 60 degrees beta misfit dislocations, respectively. Finally, the dislocation climbing mechanism and the evolution of the antisite defects As-Ga/In are discussed for n-type In0.53Ga0.47As. Published by AIP Publishing.