Atomic-resolution imaging of lattice imperfections in semiconductors by combined aberration-corrected HRTEM and exit-plane wavefunction retrieval

Abstract

With improvements in the instrumental information limit and the simultaneous minimization of image delocalization, high-resolution transmission electron microscopy is presently enjoying increased popularity for the atomic-scale imaging of lattice imperfections in solid-state materials. In this study, the benefits of a combination of spherical aberration-corrected imaging and numerical retrieval of the exit-plane wavefunction from a focal series of micrographs are illustrated by highlighting their combined use for atomic-scale characterization of lattice defects frequently observed in common semiconductor materials. Thus, experimental analyses will review the core structure of Lomer dislocations at In_0.3Ga_0.7As/GaAs heterointerfaces and focus on atomic lattice displacements associated with extrinsic stacking faults in GaAs, as well as on the core structure of chromium implantation-induced Frank partial dislocations in GaN at directly interpretable contrast features. Supplementary, practical advantages of the retrieval of the exit-plane wavefunction for the subsequent numerical elimination of residual lens aberrations are demonstrated.

Acknowledgements

The authors are grateful to Arno Förster and Vitaly Guzenko for making available the samples investigated in this study, as well as Doris Meertens for specimen preparation work.