Abstract :
Electron-assisted chemical etching of oxidized chromium, CrOx, has been studied by scanning electron microscopy (SEM),
energy dispersive spectroscopy (EDS) and atomic force microscopy (AFM). Two model substrates were used—10 nm CrOx
deposited on Si(1 0 0) that was covered with either native oxide or a 20 nm Au/Pd alloy film. Using chlorine and/or oxygen as
etching gases, the experiments were conducted in a customized high vacuum system, equipped with a high density electron
source and a low pressure reaction cell. On both substrates, electron-assisted chemical etching of CiOx was detected by SEM,
EDS and AFM. Making the method questionable for etching applications, there is substantial substrate damage associated with
the etching. The SEM images indicate strongly inhomogeneous material removal, apparently initiated and propagated from
specific but unidentified sites. In the experiments involving the Au/Pd film, there was phase separation of Au and Pd, and
dewetting to form metallic islands. AFM data show that the etched holes were as deep as 200 nm, confirming relatively rapid
etching of the Si substrate after the top layer of Cr oxide was removed.
