Structural and morphological control of nanosized Cu islands on SiO2 using a Ti underlayer

The structure and morphology of nanosized Cu islands grown by sputter deposition on clean SiO2 substrates and Ti-underlayered SiO2 substrates are investigated using transmission electron microscopy. On SiO2, spherical Cu islands with a random crystalline orientation are formed, whereas on Ti/SiO2, semispherical islands with a preferred <111> crystalline orientation are formed. Moreover, the Cu islands on Ti/SiO2 have smaller sizes, shorter interisland distances, and a higher number density than those on SiO2. These structural and morphological changes at the nanoscale are discussed from the viewpoint of interfacial interactions. Our study suggests that by using an appropriate metal underlayer, it is possible to fabricate nanosized islands with the desired wettability, crystalline orientation, as well as morphology of island ensembles