Application of a position-sensitive detector to atom probe microanalysis

Abstract

A position-sensitive detector system based on a wedge-and-strip anode has been used to build a short flight-path atom probe which identifies both the chemical nature and position of single atoms field evaporated from the surface of a field-ion specimen. The detector also allows digitized field-ion images to be obtained from the region being analyzed. The prototype instrument has a lateral resolution during analysis of substantially below 1 nm, and a depth resolution of one atomic layer. Initial applications of the instrument to the analysis of nanometer-scale precipitates in metallic alloys has shown the capability of reconstructing the three-dimensional microstructure and microchemistry of materials.