Copper CVD chemistry on a reactive substrate: bis(hexafluoroacetylacetonato)copper and hfacH on platinum (111)

Abstract

The chemistry of the copper CVD precursor Cu(hfac)[sub 2] and of the related hfacH molecule on the Pt(111) surface has been investigated using vibrational (FTIR) spectroscopy, thermal desorption measurements, and Auger spectroscopy. At high coverages, Cu(hfac)[sub 2] adsorption leads to the formation of a [open quotes]standing-up[close quotes] hfac [OC(CF[sub 3])CHC(CF[sub 3])O], adsorbed with its OCCCO skeleton essentially perpendicular to the surface. In the case of hfacH adsorption, and also for lower coverages of Cu(hfac)[sub 2], a different surface species is formed that is tentatively identified as [open quotes]lying-down[close quotes] hfac, i.e., hfac adsorbed with the OCCCO plane essentially parallel to the surface. The hfac species begin to decompose below 300 K. In the case of a saturated layer of hfacH, a large mass 69 (CF[sub 3][sup +]) thermal desorption signal is observed centered near 295 K, accompanied by the formation on the surface of both carbon monoxide and fluorine containing fragments. The carbon monoxide desorbs near 430 K, with nearly simultaneous HF desorption. Above this temperature, only two fluorocarbon species are present on the surface in significant concentration. The first (unidentified) fragment is characterized by an intense CF stretch near 1250 cm[sup [minus]1]. Between 450 and 750 K it convertsmore » to adsorbed CF[sub 2], which desorbs or decomposes below 850 K. 36 refs., 10 figs., 1 tab.« less