Advancements in the semiconductor industry require new materials withimproved performance. With the introduction of copper as the interconnect material forintegrated circuits, efficient diffusion barriers are required to prevent the diffusion ofcopper into silicon, which is primarily through grain boundaries. This dissertationreports the processing of high quality stoichiometric thin films of TiN, TaN and HfN,and studies their Cu diffusion barrier properties.Epitaxial metastable cubic TaN (B1-NaCl) thin films were grown on Si(001)using an ultra-thin TiN (B1-NaCl) seed layer which was as thin as 1 nm. The TiN/TaNstacks were deposited by Pulsed Laser Deposition (PLD), with the TiN thicknesssystematically reduced from 15 to 1 nm. Microstructural studies included X-raydiffraction (XRD), transmission electron microscopy (TEM) and high resolution TEM(HRTEM). Preliminary Cu diffusion experiments showed that the TiN seed layerthickness had little or no obvious effect on the overall microstructure and the diffusionbarrier properties of the TaN/TiN stacks. Epitaxial and highly textured cubic HfN (B1-NaCl) thin films (~100 nm) weredeposited on MgO(001) and Si(001) using PLD. Low resistivities (~40 mu omega-cm) weremeasured with a four point probe (FPP). Microstructural characterizations includedXRD, TEM, and HRTEM. Preliminary Cu diffusion tests demonstrated good diffusionbarrier properties, suggesting that HfN is a promising candidate for Cu diffusionbarriers.Cubic HfN (B1-NaCl) thin films were grown epitaxially on Si(001) substrates byusing a TiN (B1-NaCl) buffer layer as thin as ~10 nm. The HfN/TiN stacks weredeposited by PLD with an overall thickness less than 60 nm. Detailed microstructuralcharacterizations included XRD, TEM, and HRTEM. The electrical resistivity measuredby FPP was as low as 70 mu omega-cm. Preliminary copper diffusion tests showed gooddiffusion barrier properties with a diffusion depth of 2~3 nm after vacuum annealing at500 degrees C for 30 minutes.Additional samples with Cu deposited on top of the cubic HfN/TiN/Si(001) werevacuum annealed at 500 degrees C, 600 degrees C and 650 degrees C for 30 minutes. The diffusivity of copperin the epitaxial stack was investigated using HRTEM. The measured diffusion depths,2 Dt , were 3, 4 and 5 nm at 500 degrees C, 600 degrees C and 650 degrees C respectively. Finally, thediffusivity of Cu into epitaxial HfN was determined to be D=D0 exp(-Q/kT)cm2s-1 with D0=2.3x10-14cm2s-1 and Q=0.52eV.
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