EFFECTS OF ATOMIC-HYDROGEN ON CU(II) BISHEXAFLUOROACETYLACETONATE INTERACTIONS WITH A TIN SURFACE

Cu(II)bishexafluoroacetylacetonate [Cu(II)(hfac)2] adsorbed onto a par tially oxidized TiN substrate [TiN(O)] is reduced to Cu(0) by exposure to atomic deuterium at 450 K. Initial precursor interaction with the TiN(O) surface at 450 K results in an ad-layer consisting of Cu(I)hfac and hfac. Subsequent exposure to atomic deuterium at 450 K results in volatilization of organic species and reduction of Cu(I) to Cu(0). Th is reduction is concurrent with the removal of 50% of the Cu atoms fro m the surface. This indicates that the reduction involves a disproport ionation of adsorbed Cu(I) species to yield adsorbed Cu(0) and a volat ile Cu(II) species. The disproportionation is not observed in the abse nce of atomic deuterium and volatilization of adsorbed hfac. Atomic de uterium also removes adventitious carbon from a TiN(O) surface prior t o precursor exposure. The removal of carbon is accompanied by substant ial reduction of Ti(IV) to Ti(II) within the substrate surface region. Diffusion of Cu into the cleaned TiN(O) substrate begins above 450 K, but only becomes significant as the sample is heated above 750 K in u ltra-high vacuum. These results indicate that atomic-hydrogen-assisted CVD is effective at inhibiting organic contamination at the Cu/TiN in terface, and does not significantly degrade the diffusion barrier prop erties of the TiN substrate.