The Decomposition of tBAA on the Silicon Surface

ABSTRACTAmong the copper precursors used, cupric β-diketonate complexes exhibit a high sublimationrate and a low pyrolysis temperature. This work explored the possibility of using a nonfluorinated t-butylacetato complex of Cu(II) as the precursor. Secondary ion mass spectrometry and temperature-program desorption studies on the adsorption and decomposition of the ligand, tert-butyl acetoacetate (tBAA), of this precursor on Si(100) showed that at low doses, all tBAA molecules dissociated readily upon adsorption on the surface at substrate temperatures as low as –160°C. For dissociation through tBAA bonding via the ester oxygen to the surface, the bond scission occurring at the tBu-O bond resulted in the formation of surface tert-butylfragments, which in turn underwent a β-hydride elimination reaction to yield isobutene and surface hydride. In addition, the bond scission occurring at the tBuO-CO bond produced surface tert-butoxy specie, of which the hydrogen atom in the â position can be transferred to the oxygen atom of the butoxy group to yield isobutene and surface hydroxyl species. Its implication in the quality of the copper film generated is discussed.