Influence of substrate temperature on glancing angle deposited Ag nanorods

When Ag sculptured thin films were grown with glancing angle deposition by ion beam sputtering at either room temperature or elevated substrate temperatures T-S, a large morphological difference was observed. The incident particle flux reached the silicon substrate at a glancing angle beta >= 80 degrees as measured to the substrate normal. A slit aperture was used in order to reduce the particle beam divergence. At room temperature, columnar structures were formed, irrespective of the presence of the slit aperture. At elevated temperatures (573 and 623 K) and collimated particle flux in the presence of the slit aperture, however, enhanced surface diffusion causes the growth of crystalline nanorod- and nanowirelike structures. In the absence of the slit aperture, the flux beam divergence is higher, resulting in island- and mountainlike crystalline structures. The density of the nanorods and nanowires was observed to be higher on the planar Si substrates in comparison to honeycomblike prepatterned substrates with different pattern periods. On the patterned substrates, the nanorods are not necessarily found to be evolving on the seed points but can rather be also observed in-between the artificial seeds. The glancing angle deposited films at high temperatures were observed to be polycrystalline, where the (111) crystal orientation of the film is dominant, while the presence of the less intense (200) reflection was noticed from the x-ray diffraction measurements. In contrast, compact thin films deposited with beta approximate to 0 degrees at high temperatures were found to be epitaxial with (200) orientation. (C) 2010 American Vacuum Society. [DOI: 10.1116/1.3447231]