RESOLUTION AND SENSITIVITY OF ELECTRON BACKSCATTERED DIFFRACTION IN ACOLD FIELD-EMISSION GUN SEM

The tradeoff between sensitivity and spatial resolution is inherent in all analytical techniques. Electron backscattered diffraction (EBSD) in a scanning electron microscope (SEM) is no exception, and determini ng this tradeoff for EBSD is the focus of this contribution. Because t he specimen is tilted in EBSD (typically at 70 degrees), the spatial r esolution needs to be defined with respect to three orthogonal directi ons; as lateral resolution (within the specimen plane but normal to be am direction), longitudinal resolution (within the specimen plane but parallel to beam direction) and depth resolution (extent of depth info rmation). The significance of these different resolution criteria beco mes relevant for interface analysis, and is demonstrated using a varie ty of materials systems and electron-optical parameters. The sensitivi ty of EBSD is directly related to the ability of backscattered electro ns (BSEs) to produce sufficient contrast in the Kikuchi pattern at the recording medium (phosphor in our case). The various parameters which govern the sensitivity of EBSD are discussed with the help of experim ental analysis. It is argued that EBSD/OIM is a viable technique even in a cold field emission gun SEM, where there is less absolute current available and stability of current is less than for other electron so urces.