CU-METAL INTERFACIAL INTERACTIONS DURING METAL-ORGANIC CHEMICAL-VAPOR-DEPOSITION

The interactions of Cu(II) bishexafluoroacetylacetonate (Cu-II(hfac)(2 )) with polycrystalline Ta surfaces under ultrahigh vacuum conditions are reported here for temperatures between 115 and 1000 K. Cu-II(hfac) (2) adsorbed at 115 K is reduced to Cu(O) by 450 K without the use of an external reducing agent. The reduction occurs without disproportion ation of Cu(I) intermediates. This behavior is unique to Ta and differ s sharply from reported results for TiN or other metallic substrates. The Cu overlayer is stable on the Ta surface to 750 K. Between 750 and 950 K a decrease in Cu intensity is observed which becomes more prono unced above 950 K. This decrease in Cu intensity is due to diffusion o f Cu into the Ta substate.