Single atom gas field ion sources for scanning ion microscopy

Abstract

This chapter discusses fabrication and experimental evaluation of W(111) single atom tips (SATs) for gas field ion source applications. Firstly, a brief history of field ion microscopy (FIM) will be given since it will be heavily relied on throughout the text. We will discuss ion current generation in FIM and carry that knowledge over to fabricated SATs. Secondly, gas assisted etching and evaporation process will be discussed in detail. It will be shown that nanotip shape, and therefore SAT characteristics, can be controlled and modified to achieve desirable ion beam properties. Lastly, we will evaluate ion beam width as a function of tip voltage and temperature as examples of experimental efforts to better understand gas field ion source performance.