Comparative Study of the Growth Characteristics and Electrical Properties of Atomic-layer-deposited W Films Obtained from Newly Synthesized Metalorganic and Halide Precursor

Tungsten (W) has a wide range of industrial applications since it has several advantages such as high conductivity, thermal stability, and electromigration durability. We report the properties of plasma-enhanced atomic-layer-deposited (ALD) tungsten (W) thin films. ALD is promising deposition method for obtaining thin films with good conformality, good uniformity, and low impurity contamination, as its growth mechanism is entirely based on self-limited surface reaction. Thus, the choice of an appropriate precursor for ALD is critical for obtaining high-quality films. We comparatively investigate the growth characteristics and film properties using two newly synthesized precursors, tungsten pentachloride (WCl5) and ethylcyclopentadienyltungsten(V) tricarbonyl hydride (HEtCpW(CO)3), and Ar/H2 plasma as the reactant. Growth characteristics and film properties were significantly affected by ligands of precursors. These results provide fundamental and useful information, with respect to the selection of the suitable precursor, for practical implementation of device fabrication.