Palladium Thin Films Grown by CVD from (1,1,1,5,5,5‐Hexafluoro‐2,4‐pentanedionato) Palladium(II)

Abstract

The precursor (1,1,1,5,5,5‐hexafluoro‐2,4‐pentanedionato) palladium(II) [Pd(hfac)₂] was used to deposit high‐purity, polycrystalline palladium films under low‐pressure CVD conditions at high growth rates (1000–4000 Å/min) over a substrate temperature range of 80–200°C in the presence of H₂. Mixing of the precursor and H₂ streams near the substrate was required to avoid reactions of the precursor with H₂ at locations other than the substrate surface. Auger electron spectroscopy (AES) showed that the films were impurity free when sufficient H₂ was used. Resistivity values of 20 μΩcm were obtained at the higher deposition temperatures (∼200 °C) while high values of 50 μΩ cm were observed at the lower deposition temperatures (∼ 90 °C). The deposition rate was feed‐rate limited even at the lowest deposition temperatures and highest precursor delivery rates, suggesting that even higher deposition rates could be obtained with higher feed rates. A high precursor conversion of 50–60 % was observed. The high surface reaction probability of Pd(hfac)₂ in the presence of H₂ was reflected qualitatively by trench fill studies which showed a greater film thickness on the top of sub‐micrometer trenches than in the bottom.