Jing Fu et al 2008 J. Micromech. Microeng. 18 095010 doi:10.1088/0960-1317/18/9/095010
Jing Fu1, Sanjay B Joshi1 and Jeffrey M Catchmark2
Show affiliationsFocused ion beam (FIB) milling in a cryogenic environment has the potential to serve as a cryotome to section frozen biological samples, or as a patterning tool for submicron features on organic materials. Although FIB milling of inorganic materials has been investigated extensively, ion–ice interactions and the effects of process parameters on milling characteristics remain largely unexplored. In this study, the effect of the incident angle during FIB milling of water ice was investigated. In particular, the sputtering yield and surface morphology that result from sputtering were examined. The experiments involved ion bombardment by 30 keV Ga+ on a thin film of water ice with temperature maintained at 97 K. The results show that the sputtering rate, determined by a volume loss method, increased with increasing incident angle. The maximum sputtering rate was achieved at an incident angle of approximately 70°, and dramatically decreased from 70° to 90°. Depending on the angle of incidence, different surface morphologies developed during ion bombardment and were confirmed by SEM imaging and texture analysis. At near normal incidence, dome/pillar morphology was observed and it evolved to step/terrace morphology as the incident angle approached 40°. The smoothest ion bombarded surfaces were observed at grazing angles.
68.35.B- Structure of clean surfaces (and surface reconstruction)
68.55.-a Thin film structure and morphology
61.80.Jh Ion radiation effects
68.49.Sf Ion scattering from surfaces (charge transfer, sputtering, SIMS)
79.20.Rf Atomic, molecular, and ion beam impact and interactions with surfaces
Condensed matter: electrical, magnetic and optical
Issue 9 (September 2008)
Received 3 May 2008, in final form 30 June 2008
Published 29 July 2008
Jing Fu et al 2008 J. Micromech. Microeng. 18 095010
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