NEW MICROSCOPY CAPABILITY AT NIST.

NIST has a new field-emission scanning electron microscope (FE-SEM) capable of high spatial resolution microstructural characterization of a wide variety of metal, ceramic, and polymer structures. This microscope has accelerating voltages from 500 V to 30 kV with spatial resolutions of 1.5 nm at 15 kV and 2.5 nm at 1 kV. The ability to maintain high resolution even at lower voltage allows the investigation of uncoated, nonconducting specimens, such as ceramics and polymers. The microscope is equipped with an energy dispersive x-ray spectrometer (EDS), back-scattered electron (BSE) detector, and faraday (picoampere) cups. The microscope has an improved objective lens electron detector system, which can be continuously adjusted to allow for imaging with secondary or backscattered electrons. This improved design allows BSE imaging at low voltages (less than 5 kV) where conventional BSE de tectors are unsuitable. The new FE-SEM is expected to benefit a wide range of NIST research programs through high resolution materials characterization. The microscope is currently being used to evaluate the structures and compositions of thin- film multilayers, highly deformed metals, copper on-chip metallization, ceramic fracture surfaces, nanostructured powders, polymers with nano-scale porosity, and lithography masks.