Deep-Level Transient Spectroscopy of Plastically-Bent Epitaxial GaAs

Abstract

Trap levels in plastically-bent vapor-phase epitaxial (VPE) and liquid-phase epitaxial (LPE) GaAs n-layers were investigated by deep-level transient spectroscopy (DLTS). Two hole traps, Level A(E _v+0.38 eV) and Level B(E _v+0.68 eV), and one electron trap, EL2(E _c-0.82 eV), were found after deformation, as well as hole traps due to Cu and Fe contaimnation. No trap levels attributable to the dislocations in GaAs were found. The total amount of additional trap concentrations detected by DLTS measurements fell fairly far short of the reduction in the free carrier concentration, owing to deformation. These findings suggest that dislocation-associated traps in GaAs in themselves do not show a peak in DLTS spectra. This is tentatively discussed in connection with recent reports on the degradation of light-emitting devices.