Properties of a new organo silver compound for MOCVD

Abstract

Trans-bis(trimethylsilyl)ethene(1,1,1,5,5,5-hexafluoro-2,4-pentanedionato)Ag(I), (BTMSE)Ag(hfac) was found to be a very promising compound for CVD Ag wiring. It is a solid at r.t. (m.p. 70°C), has a vapor pressure (10 −3 Torr at r.t.) and high thermal stability, and can be used as a precursor for MOCVD. Thermal and laser CVD silver films were grown on TiN Si(100) from (BTMSE)Ag(hfac) in a quartz vacuum chamber, using thermal activation by an electric heater or photo activation through a quartz window with an excimer laser (XeCl, 308 nm). The chamber pressure was varied from 2 to 30 Torr. The evaporation temperature was kept at 80°C. Ar gas was used as the carrier with a flow rate in the evaporation cylinder varying from 50 to 200 ccm. A growth rate of 3 nm/min was achieved at 200°C, an evaporation temperature of 80°C, an argon flow rate of 100 ccm and a chamber pressure of 10 Torr. Resistivities were of the order of about 10 −3 cm depending on the film morphology. With laser CVD, a growth rate of 3 nm/min was achieved by laser activation at 80°C, an evaporation temperature of 120°C, an argon flow rate of 100 ccm and a chamber pressure of 10 Torr. Resistivities were of the order of about 10 −6 Ω cm depending on the film morphology. The laser CVD results were far better than the thermal CVD ones. The film morphology was finer and more evenly distributed with a faster growth rate at much lower temperatures.