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ABSTRACT The chemical vapor deposition (CVD) of Cu-Ag and Cu-Pd alloys using aerosol precursor delivery over a range of preheating temperatures, 70-80 oC and substrate temperatures, 250-300 °C is described. The precursors used include Cu(hfac)2, (hfac)Ag(SEt2) and Pd(hfac)2 dissolved in toluene and 10% H2 in Ar as carrier gas. The films were characterized by SEM, EDS and X-ray diffraction (XRD). The X-ray diffraction results showed the Cu/Ag films were composed of aand Il-phases of Cu-Ag alloys, the Cu/Pd films were Cu-Pd alloy, solid solutions, under these conditions. Compositional variation studies in Cu-Pd and Pd-Ag alloy systems were also conducted by mixing Cu(hfac)2/Pd(hfac)2 and (hfac)Ag(SEt 2)/Pd(hfac)2 in toluene solution in different ratios. The films were characterized by X-ray diffraction and the results showed the composition of films was affected by the solution stoichiometry.

INTRODUCTION Metal alloy thin films have many applications ranging from interconnects in semiconductor device manufacture [1] to gas permeable membranes in separations technology. [2] Chemical vapor deposition (CVD) is an attractive method of deposition of metal alloy films because comformal coverage and uniform deposition can be obtained. The key to success of CVD of alloys is the selection of suitable precursors to avoid unfavorable reactions before deposition. However, CVD with conventional delivery is often limited by the low volatility and low thermal stability of the precursors. Furthermore, the composition of an alloy is generally hard to control using conventional precursor delivery. Aerosol delivery provides an alternative route to conventional delivery. [3] In this method, the precursor is first dissolved in a solvent. The solution is passed through an aerosol generator, where micron-sized aerosol droplets are generated in a carrier gas and are transported into a preheating zone where both solvent and the precursor evaporate. Then the precursor vapor reaches the heated substrate surface where film deposition takes place. Aerosol delivery overcomes many of the problems associated with conventional delivery. Aerosol delivery enables a high mass transport rate of the precursor to substrate which can result in a high deposition rate, but does not require high precursor vapor pressure or long-term thermal stability of the precursor at elevated temperature. In addition, the system can be operated under conditions where the precursor delivery rate and the composition of precursors in solution and droplets do not change with time, which allows reproducible deposition of multicomponent films, such as alloys. This method has not been studied extensively for metal CVD. [3] The CVD of low resistivity Cu films has been achieved from toluene solutions of (hfac)Cu(1,5-COD), where 1,5COD is 1,5-cyclooctadiene, at high rate -800 A/min. and low temperature (140 CC). [4] In addition, pure Ag films also have been obtained at substrate temperature as low as 120 °C, using the precursor (hfac)Ag(SEt2) which has low volatility and low therma