Morphological and magnetic study of plasma assisted solid-state dewetting of ultra-thin cobalt films on conductive titanium silicon nitride supports

Abstract

Since metals are high-surface energy materials, it is difficult to stabilize metal nanoparticles on conductive substrates, on the other side, producing nanoparticles on low surface energy oxides is hindered by high temperature activated phenomena such as diffusion on the surface as well as in the bulk. In this work, we present a simple and efficient approach to produce controlled cobalt (Co) magnetic nanoparticles by solid state dewetting of sub 3 nm metal films deposited on conductive and low surface energy titanium silicon nitride (TiSiN) barriers. For this purpose, ultrathin Co films with thickness of 1, 2 and 3 nm were first deposited on the top of the TiSiN layer; then Co films were submitted to different variations of dewetting protocols. Solid state dewetting process will be analyzed from kinetic and thermodynamic points of view. Structural and magnetic characterizations of the patterned nanoparticles showed that the size, the density and the structure of the generated nanoparticles are well controlled using TiSiN barrier and plasma treatment. The magnetic measurements showed relatively high coercivity and confirmed that dewetting parameters can be used to tune the design of nanoparticles and their size distribution on TiSiN substrates, thereby providing a promising tool to control their coercive field.