Frictional characteristics of a nanoporous SiO 2 film with a surface-treated by chemical mechanical polishing

Abstract

The use of nanoporous thin films has proven to be beneficial when surface interactions occur. The porous structure inside the films has the capacity to store lubricating materials, such as oil or carbon, which can provide good wear resistance and lubrication performance. If such performance is to be obtained, a uniform pore size and structure is very important. In this study, nanoporous SiO 2 films were deposited on silicon wafers by using a sol-gel method. The porous structure was developed using a surfactant of pluronic (F127) and cetyltrimethylammonium bromide (CTAB). The surfaces of these films were treated using a chemical mechanical polishing (CMP) process. Before and after the surface treatment, the films were evaluated using a ball-on-disk-type friction and wear tester to obtain the frictional characteristics. The films with a porous structure showed a lower coefficient of friction (COF) than those without pores. The COF decreased even more after the films were surface treated by CMP. The surface roughness appeared to affect the frictional characteristics more strongly after CMP. In addition, the wear resistance differed with the type of porous structure.