ISSN:
0142-2421
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Physics
Notes:
Atomic force microscopy (AFM) is used to compare the topography of the ion-bombarded surfaces of Ge(111), atomically flat terraces on strained layers of In0.22Ga0.78As on GaAs and alpha quartz.Germanium samples were bombarded with 100 keV Ge+ ions at doses of up to 1016 ions cm-2. A cellular structure with a mean pore diameter of 50 nm was observed at greater detail but similar to that reported in earlier scanning electron microscope (SEM) measurements [I. H. Wilson, J. Appl. Phys. 53, 1698-1705 (1982)]. It is proposed that this structure is formed by the intersection of the etched surface with point defect clusters created in the dense collision cascade, and the combined effects of sputter etching, ion reflection and redeposition.Individual impact craters are observed on As+- and B+-bombarded In0.22Ga0.78As/GaAs (35 keV, 1011 ions cm-2) at the areal density identical to that of ion impacts. The craters arising from As+ bombardment are attributed to damage associated with nuclear stopping in the primary collision cascade.By contrast, alpha quartz samples bombarded with a wide range of ions (Pb, Ni, O, Si, Ar and In at doses of 1010-1011 ions cm-2) and energies (30 keV to 0.73 GeV) exhibit asperities (bumps). In the case of very high energy ions, the areal density of asperities is much less than that of ion impacts. The asperities are attributed to volume expansion associated with amorphous zone creation. In the case of very high energy ions, zone creation is attributed to energetic knock-on cascades directed back towards the surface.
Additional Material:
8 Ill.
Type of Medium:
Electronic Resource
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