Kinetic study on hot-wire-assisted atomic layer deposition of nickel thin films Available to Purchase

High-purity Ni films were deposited using hot-wire-assisted atomic layer deposition (HW-ALD) at deposition temperatures of 175, 250, and 350 °C. Negligible amount of nitrogen or carbon contamination was detected, even though the authors used NH₂ radical as the reducing agent and nickelocene as the precursor. NH₂ radicals were generated by the thermal decomposition of NH₃ with the assist of HW and used to reduce the adsorbed metal growth precursors. To understand and improve the deposition process, the kinetics of HW-ALD were analyzed using a Langmuir-type model. Unlike remote-plasma-enhanced atomic layer deposition, HW-ALD does not lead to plasma-induced damage. This is a significant advantage, because the authors can supply sufficient NH₂ radicals to deposit high-purity metallic films by adjusting the distance between the hot wire and the substrate. NH₂ radicals have a short lifetime, and it was important to use a short distance between the radical generation site and substrate. Furthermore, the impurity content of the nickel films was independent of the deposition temperature, which is evidence of the temperature-independent nature of the NH₂ radical flux and the reactivity of the NH₂ radicals.