Properties of Sputtered Molybdenum Silicide Thin Films

The structural, compositional, and electrical properties of molybdenum silicide (with an Si/Mo ratio between 2 and 2.3) thin films either sputtered from a hot‐pressed, composite target or cosputtered from elemental targets are compared. Structural and compositional examination was performed with x‐ray diffraction, Rutherford backscattering spectrometry (RBS), and secondary ion mass spectrometry (SIMS). X‐ray diffraction revealed that the as‐deposited silicide films were essentially amorphous but, after high temperature annealing, contained mostly tetragonal . SIMS depth profiling showed that the concentration of carbon and argon is lower in the cosputtered films but that of oxygen is higher than the alloy‐sputtered films. This difference is attributed to the target purity and sputtering system configuration. Isothermal and isochronal annealing resulted in a minimum resistivity of ∼100 μΩ‐cm in both cases. C‐V measurements of silicide‐gate capacitors with both types of films yielded similar values of work function and surface‐state density.