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

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. Full Paper: There has been no complete study of the kinetics of Pd growth, and this is necessary before a CVD process can be implemented for thin film applications. Here it is shown that there is a high surface reaction probability of the precursor Pd(hfac)2 in the presence of H2, which is reflected by trench fill studies, where there is a greater film thickness on top of sub‐micron trenches than in the bottom (see Figure).