Vapor Deposition of Ruthenium from an Amidinate Precursor

Abstract

Atomic layer deposition (ALD) and pulsed chemical vapor deposition (CVD) were used to make ruthenium (Ru) thin films from a volatile Ru amidinate precursor, bis(-di-tert-butylacetamidinato)ruthenium(II) dicarbonyl. The CVD films were grown without any coreactant, while the ALD films used ammonia as a coreactant. The films are fine-grained polycrystalline ruthenium with high purity ( impurities). Ru grew as a continuous, electrically conductive, pinhole-free film on tungsten nitride (WN) films even for films as thin as . The resistivities of the films match those of pure sputtered ruthenium of the same thickness. Roughness is of the film thickness. The films are very conformal, with 80% step coverage over holes with high aspect ratios (40:1). This thermal process does not use any oxidant or plasma as a second reagent, thereby avoiding damage to sensitive substrates. The ALD growth rate can reach at a substrate temperature of .