Electron beam-induced current imaging of antiphase domain boundaries in heteroepitaxial GaAs on group IV semiconductors

Abstract

A viable GaAs heteroepitaxy technology is desirable in order to exploit the high mobility and direct band gap properties of GaAs while avoiding the high cost, defect density, and weight of bulk GaAs. Microstructural defects such as dislocations, microtwins, and stacking faults found in most heteroepitaxial GaAs films have thus far inhibited the achievement of device quality films. In addition, the formation of antiphase domain boundaries (APBs), at which As-As bonds and Ga-Ga bonds exist, is undesirable because they are electrically active. The APBs are believed to form due to the presence of single atomic steps on the underlying group IV substrate. Transmission electron microscopy investigations have previously reported the presence of APBs in GaAs heteroepitaxial films. Since the APBs act as electron-hole recombination sites, the electron beam-induced current. (EBIC) imaging mode of the scanning electron microscope (SEM) is ideally suited for straightforward and statistically significant. GaAs heteroepitaxial film evaluation.