Development of the Scanning Atom Probe and Atomic Level Analysis

Abstract

The analyzing area of a conventional atom probe is an apex of a long, sharp tip. However, the fabrication of such a filamentary tip is extraordinary difficult for most materials, such as organic materials, ceramics and semiconductors with multi-layer structures. Accordingly, the application of the atom probe are severely restricted In order to overcome this difficulty, Nishikawa proposed to develop a scanning atom probe (SAP) introducing a funnel-shaped microextraction electrode to the conventional AP in order to confine the high field into a small space between a tip apex and an open end of the electrode. Thus, the SAP allows to analyze not only an apex of a sharp slender tip but also an apex of a few micron high minute cusp which normally exists on an unsmoothened specimen surface.The microextraction electrode scans over a rugged specimen surface at a bias voltage and stands still right above an apex of a micro cusp, FIG. 1.