Tert-butylamine and Allylamine as Reductive Nitrogen Sources in Atomic Layer Deposition of TaN Thin Films

Abstract

The atomic layer deposition technique was used to deposit TaN thin films from TaCl₅ and TaBr₅ and tert-butylamine or allylamine as a reductive nitrogen source with and without ammonia. The films were characterized with time-of-flight elastic recoil detection analysis, energy-dispersive x-ray spectroscopy, x-ray diffraction, and the standard four-point probe method. The films deposited from tert-butylamine and ammonia with both tantalum precursors had reasonably low halide contents. When allylamine was used as a nitrogen source, on the contrary, the films contained larger amounts of chlorine and other impurities. The resistivity increased markedly as the deposition temperature was decreased. The lowest resistivities (below 1500 μΩ cm) were obtained when the films were deposited from TaCl₅ or TaBr₅ with tert-butylamine at 500 °C.