Etch Effects from Oblique-Incidence Ion Bombardment

Abstract

It has been found that metallic surfaces of Cu, Au, Al, W, Ta, Mo, and Ni when bombarded with 500-v Hg+ ions at angles of incidence other than zero, exhibit a definite surface structure or pattern. This pattern consists of hillocks or spires oriented parallel to the direction of the incoming ion beam. In Cu and Ni, steps oriented perpendicularly to the ion beam were also found. This surface pattern provides visual evidence that the sputtering process at low ion energies is a momentum transfer process. Since redeposition of sputtered atoms on the hillocks and steps could be quite large, angle of incidence yield measurements could be in error unless they are made before formation of the hillocks.

Fundamental studies of a gas-jet-enhanced sputtering system for atomic spectroscopy

“…Therefore an examination of the resulting surface features is important to a fundamental investigation of sputtering. More than 40 years ago, conelike formations were reported (62), and with the subsequent availability of the scanning electron microscope, more investigators have examined the surface effects of ion sputtering (57)(58)(59)(63)(64)(65)(66)(67). The factors that affect the surface features include fill gas, cathode material, sputtered time, discharge current density, discharge voltage, gas pressure, and in this study, gas flow rate.…”

Sputter-Atomization Studies with a Glow Discharge

“…The extent to which this microroughening occurs can influence analytical results, probably by affecting the net surface area and the sputter rate of analytical residue films. Over 30 years ago, cone-like formations were noted (22) and with the subsequent availability of the SEM, more investigators have examined the surface effects of ion sputtering (21)(22)(23)(24)(25)(26)(27)(28)(29). An examination of the literature shows that there is no unified theory to explain these phenomena, although a recent review (29) attempts to correlate some of the studies.…”