Metal Nanowhiskers Synthesized by High-temperature Glancing Angle Deposition

We have demonstrated high-temperature glancing angle deposition (HT-GLAD) of Al on a heated substrate with trench patterns. The nanowhiskers grow not only on the illuminated sidewall but also on the shadowed sidewalls, while few nanowhiskers grow on the shadowed region at the bottom of the trenches. In addition, the size and number of nanowhiskers growing on the sidewall depend strongly on the angle between the incident direction of the vapor flux and the trench directions, although actual angle of inicidence of the vapor flux on the sidewall is kept constant. In order to understand the peculiar growth of Al nanowhiskers, novel transport processes of Al atoms other than surface diffusion need to be elucidated. The reflective scattering on the sidewalls of the trenches is likely to play an important role in the growth of nanowhiskers. On the other hand, we demonstrate the HT-GLAD of metals other than Al. It has been found that nanowhiskers of Cu, Ag, Au, Mn, Fe. Co, Ni and Zn as well as Al grow on the substrates of SiO(2). The robustness in the selection of materials suggests that HT-GLAD is a general method for growing metal nanowhiskers. However, since growth mode of nanowhisker is complicated, further detailed investigation is required for fully understanding of the growth mechanisms of the nanowhiskers by HT-GLAD.