Crystallographic phase identification in the SEM: Backscattered electron kikuchi patterns

Abstract

The use of the recently developed charge coupled device (CCD)-based detector for the acquisition of high quality backscattered electron Kikuchi patterns (BEKP) has allowed on-line crystallographic phase identification studies to be conducted in the scanning electron microscope. High quality patterns suitable for analysis have been obtained in a wide variety of materials with little special specimen preparation. Phase identification through a combination of BEKP and energy dispersive x-ray spectrometry (EDS) is demonstrated by the identification of crystals present on ruthenium oxide thin films on Si. The crystals were identified as RuO2, a tetragonal phase.The CCD-based detector has been described previously and will only be briefly described here. The detector consists of a scientific grade slow scan CCD coupled to a YAG scintillator by a fiber optic reducer. During operation the CCD is cooled to -40°C by a thermoelectric cooler. This detector allows high quality patterns to be recorded with beam currents as low as 10-10A and exposure times of 1 to 10 seconds.