Ultramicrotomy of semiconductors and related materials

Abstract

Ultramicrotomy has found novel application in materials research using transmission electron microscopy, for both analytical and high resolution work. Specimens 20-50 nm in thickness with lateral dimensions of up to 100 microns may routinely be prepared, with the additional advantage of precise area location for cross-sectional samples from real devices (e.g., VLSI structures). Much of this work is possible through the availability of diamond knives with various included angles and lengths at reasonable cost. This paper reports on various applications of ultramicrotomy, in particular, lattice imaging of surfaces and interface regions from epilayers of II-VI compound semiconductors and related materials. Ultramicrotomed cross-sections have enabled modern electron beam imaging, diffraction and analytical techniques to be brought to bear near surfaces and across interfaces of multilayer structures, yielding high spatial resolution information on crystallography, defect structure and composition.