Nanostructured Etching of Ruthenium in Three-Component Cl2/O2/Ar Plasma

Using spectroscopic and probe diagnostic methods for diagnosing the radical composition and electronic component of a radio-frequency inductively (RFI) coupled discharge, studies are conducted on the low-energy (Ei ~ 80 eV) etching of a nanometer-thick Ru film in the remote plasma of a 50% Ar/Cl2/O2 mixture, depending on pressure, RF power, and relative Cl2/O2 content. At 10–30% chlorine content in the plasma a wide maximum of the Ru etch rate is observed. In plasma of this composition, using an array of amorphous silicon nanocones as a mask, vertical Ru nanocolumnar structures with a height of 35 nm and a distance between them of 10–20 nm are obtained. The mechanism of Ru etching in 50% Ar/Cl2/O2 plasma is discussed.