Applications of Electron Channeling Contrast Imaging for the Rapid Characterization of Extended Defects in III–V/Si Heterostructures

Electron channeling contrast imaging (ECCI) is a nondestructive diffraction-based scanning electron microscopy (SEM) technique that can provide microstructural analysis similar to transmission electron microscopy (TEM). However, because ECCI is performed within an SEM and requires little to no sample preparation, such analysis can be accomplished in a fraction of the time. Like TEM, ECCI can be used to image a variety of extended defects and enables the use of standard invisibility criteria to provide further defect characterization (e.g., Burgers vector determination). Here, we use ECCI to characterize various extended defects, including threading dislocations, misfit dislocations, and stacking faults, in heteroepitaxial GaP/Si(1 0 0) samples. We also present applications for which ECCI is particularly well suited compared with conventional methods. First, misfit dislocations are surveyed via ECCI across the radius of a 4-in GaP/Si wafer, yielding a proof-of-concept rapid (~3 h) approach to large-area defect characterization. Second, by simply wet etching away a portion of a thick epitaxial GaP-on-Si layer, we use ECCI to image specific targeted interfaces within a heterostructure. Both of these applications are prime examples of how ECCI is a compelling alternative to TEM in circumstances where the required sample preparation would be prohibitively time-consuming or difficult.