Electron beam cutting in amorphous alumina sheets

Abstract

We have found that nanometer diameter holes and slots can be cut in thin sheets of amorphous alumina using an intense electron beam. The holes, formed by a nonthermal process, are uniform in diameter, are surrounded by metallic aluminum, and can penetrate a 100-nm sheet in a few seconds. The amorphous alumina sheets are formed by anodization of electropolished high purity aluminum. The electron beam cutting seems very similar to the process reported in the metal β-aluminas. Since uniform, stable, and easily handled sheets of amorphous alumina can be fabricated and electron beam cut, this process is now practical for nanolithography as well as many other applications.