Ordered nanostructure fabrication was performed via a two-step process using electron-beam lithography and ion beam irradiation. In the first process, a well-focused electron-beam was used to fabricate ordered holes on an electron-beam resist-coated Ge wafer. In the second process, an ion beam was used to irradiate the entire surface to promote nanostructure growth through the migration of ion beam-induced interstitial atoms. The formation of nanostructures with a 26 nm thickness, 59 nm height, and an aspect ratio of 2.2 was achieved in 60 nm diameter holes with equal center-center distances. High aspect ratio nanostructures were formed via limited migration of interstitial atoms on the walls. An estimated 1.1% point defect was obtained by changing the volume of the nanostructures after irradiation, which contributed to the growth of the structures.

Articles you may be interested inImplantdose dependence of grain size and {110} texture enhancements in polycrystalline Si films by seed selection through ion channelingThe negative shifts of the threshold voltages of 75 As + -implanted Mo-gate metal-oxide semiconductor (MOS) transistors were observed under some fabrication conditions of highenergy or high-dose 75 As+ implantation, or thin-Mo-film deposition. These phenomena are attributed to 75 As atoms entering Si through Mo-film and -gate oxide by measuring C-V characteristics and observing the stain-etched cross sections of the samples directly. The present threshold voltage shifts can be almost perfectly suppressed by covering Mo-gate electrodes with 2000-A plasma-CVD silicon-nitride films during 75 As+ implantation. PACS numbers: 85.30.Tv, 85.30.De Kudoh. Murao, and Kobayashi 489 [This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation.aip.org/termsconditions. Downloaded to ] IP: 130.88.90.

We study morphological changes on the Si surface induced by the C60 ion beam under various irradiation conditions. The fluence and incident energy of the C60 ion beam was 1 × 1016–1 × 1019 ions/m2 and 50 keV–9 MeV, respectively. The beam’s incident angle to the surface normal was 0° or 60°. As a result of the changes in these variables, three types of nanostructures were observed: concave and convex, stringlike, and ripple structures. Structure shapes or sizes varied with changes in the parameters. Almost all cases showed concave and convex structures at an incident angle of 0°. At a 60° incident angle, stringlike or ripple structures were formed. Stringlike structures were formed at higher incident energy, while ripple structures were formed at lower incident energy. We found that both stringlike and ripple structures can form from sputtering and thermal effects. The formation of string structure requires a thicker amorphous layer and the proper balance of sputtering and annealing.