Low-pressure chemical vapor deposition of copper: Dependence of the selectivity on the water vapor added to a hydrogen or helium carrier gas

Abstract

The selectivity of copper deposition from copper (II) bis-hexafluoroacetylacetonate on SiO2 patterned with a platinum seeding layer is studied as a function of the reagent gas mixture. On platinum, the copper film growth rate increases with the amount of water vapor in the gas flow, and is independent of the chemical nature of the carrier gas used (H2 or He). The selectivity of the copper deposition is significantly improved when using He rather than H2 as carrier gas, especially at high water vapor concentrations where rapid film growth can be obtained.

Thin films for superconducting electronics: Precursor performance issues, deposition mechanisms, and superconducting phase formation-processing strategies in the growth of Tl2Ba2CaCu2O8films by metal-organic chemical vapor deposition

“…Large excesses of H 2 O appear to retard the Cu(hfa) 2 formation under these conditions and to reduce copper etching, resulting in a film stoichiometry being identical to gas phase composition. This is consistent with findings that H 2 O aids in the decomposition of Cu(hfa) 2 at temperatures as low as 250 ± C. 77,79 From the study of deposition rate as a function of precursor transport and substrate temperature, it can be concluded that the primary mechanism of BaCaCuO(F) MOCVD growth is mass transport-limited with the present precursor and reactor system. H 2 O in the oxidizer stream has little effect on the onset of mass transportlimited film growth for BaO and CaO deposition; however, it does significantly affect CuO deposition.…”

“…In principle, the effect of H 2 O on the decomposition of these precursors may be significant since it could act as a protonolytic reagent to form volatile Hhfa by-products. [77][78][79] To explore this possibility, the above experiment was conducted without water in the oxidizing stream. The same general results were observed with mass transport-limited deposition of Ba and Ca beginning near 400 ± C [ Fig.…”

“…12(a)] could conceivably facilitate precursor decomposition by acting as a proton source to form volatile Hhfa by-products. [77][78][79] However, only a slight influence of H 2 O on the onset temperature for masstransport limited BaCaCuO(F) film growth is observed [ Fig. 12(b)] and is surprising in view of the pronounced effect H 2 O has in accelerating the decomposition of Cu(hfa) 2 during Cu ± thin film growth.…”

“…12(b)] and is surprising in view of the pronounced effect H 2 O has in accelerating the decomposition of Cu(hfa) 2 during Cu ± thin film growth. 77,79 Interestingly, at 400 ± C, there is essentially no copper deposition. A possible explanation is that the decomposition products of Ba(hfa) 2 • mep and Ca(hfa) 2 • tet form Cu(hfa) 2 which then transports Cu from the film as in Eq.…”

Influence of Water on Chemical Vapor Deposition of Ni and Co thin films from ethanol solutions of acetylacetonate precursors

“…Only few systematic studies on the influence of water on β-diketonates under CVD conditions are available and their results often appear to be contradictory. For instance, it has been reported that CVD with a β-diketonate such as Cu(hfac) 2 as precursor in combination with H 2 as reducing agent can be area-selective, i.e., copper, in this case, is deposited on metal substrates but not on oxide areas 16 17 18 19 . When adding water to the reaction gas mixture, some authors found a loss of the precursor’s selectivity to metal substrates 19 while others reported, for apparently similar experiments, that the selectivity is unaffected 20 .…”