Structure and morphology of magnetron sputtered CoCr thin films

The growth characteristics of magnetron sputtered Co-22%Cr thin films on amorphous glass or carbon substrates have been investigated utilizing transmission electron microscopy, X-ray diffraction and electrical resistivity measurements. Results indicate that the initial deposit is “amorphous”. but that small crystallites form before the film reaches 5 nm film thickness. By 10 nm, well oriented grains with hcp c-axis perpendicular to the film plane develop, and by SO nm, a columnar microstructure is evident. A distinct subgrain structure was also observed in the thinner films (IO-50 nm), and this is reflected in the electrical resistivity. These observations cannot be accounted for by an “evolutionary selection” growth scenario. but must be related to the low surface mobility of adatoms at these low substrate deposition temperatures ( < 50°C).