Atomic-by-atom analysis of micro tip emitter surfaces by the scanning atom probe

Since the emission characteristics of a microtip array strongly depends on the geometrical configuration of the individual tip apexes and the compositional distribution of a few atomic layers of the each emitting surface area, the direct inspection of every emitting tip surface is the fundamental requirement for the development of bright, stable, reliable and highly efficient emitters. In order to realize the required inspection, the scanning atom probe (SAP) which allows us to analyze individual apexes of a microtip array at atomic resolution was developed. In order to demonstrate the unique capability of the SAP an as-grown CVD diamond surface was analyzed. Although it has been reported that even natural diamond contains a significant amount of hydrogen, the SAP has succeeded to detect a large number of field evaporated hydrogen ions and carbon and carbon-hydrogen cluster ions from the CVD diamond for the first time.