Defect characterization of etch pits in ZnSe based epitaxial layers
Three distinct etch pit features in ZnSe based epitaxial layers have been identified. The features were observed with optical dark field microscopy and confirmed to be pits using scanning electron microscopy. Using transmission electron microscopy, we associated different etch pits with characteristic crystallographic defects which are common in epitaxially grown II–VI materials. Frank‐type stacking faults form the largest etch pit followed by a paired configuration of Shockley‐ type stacking faults. The smallest etch pit is due to a single Shockley‐type stacking fault. This study represents one of the first examples of identifying crystallographic defects in II–VI wide bandgap materials using etch pit delineation.
AbstractIn most of the direct slicing strategies, the deviation between the computer aided design (CAD) model and the built-up part is estimated as the cusp height in normal vertical sections (NVSs) at points all around the slice contour. In the present investigation, the error is also estimated in inclined normal sections (INSs) in an attempt to maximize the slice height and simultaneously obtain a uniform surface roughness of the part. It is found that the number of slices is drastically reduced by the application of the proposed strategy when compared with first-order approximation with error calculation in NVSs. It is also interesting to note that slice height maximization is not necessarily accompanied with any significant, simultaneous reduction in machining time.