A nonfluorinated b-diketonate precursor, bis(t-butylacetoacetato)Cu(II) or Cu(tbaoac) 2 , was synthesized by modifying bis(dipivaloylmethanato)Cu(II) or Cu(dpm) 2 for chemical vapor deposition (CVD) of copper. The complex was characterized by a variety of techniques, such as melting point determination, mass spectrometry, infrared spectroscopy, elemental analysis, thermogravimetric and differential thermal analysis, and x-ray diffraction. Cu(tbaoac) 2 has a higher sublimation rate than Cu(dpm) 2 over the temperature range 90-150 ± C. Pyrolysis of Cu(tbaoac) 2 leads to the formation of copper films at 225 ± C, compared to 330 ± C for Cu(dpm) 2 . As-deposited copper films were highly dense, mirror-bright, adhered strongly to SiO 2 , and showed a resistivity of less than 2.9 mV-cm at a thickness as low as 1300Å. A possible mechanism for the decomposition of the ligand tbaoac has been proposed.

A potentially manufacturable liquid-source MOCVD process was applied to deposit platinum (Pt) films (12±140 nm) on thermally oxidized Si substrates. The deposition of Pt films was carried out at a substrate temperature of 350 C by oxygen-assisted pyrolysis of complex precursors in a low-pressure, hot-wall reactor. The effects of two different metal±organic precursors, a) trimethyl methyl cyclopentadienyl platinum [(CH 3 ) 3 CH 3 CpPt], and b) platinum acetylacetonate [Pt(acac) 2 ], on the properties of Pt films were studied. Although the polycrystalline Pt films deposited from Pt(acac) 2 exhibited a preferred (111) orientation with a X-ray intensity ratio of I (111) /I (200) = 40, the films deposited from (CH 3 ) 3 CH 3 CpPt were highly (111) oriented with I (111) /I (200) = 270. The following properties were typical of Pt films from Pt(acac) 2 as compared to Pt films from (CH 3 ) 3 CH 3 CpPt: finer grain size (25 nm vs. 50 nm), smaller root mean square (rms) surface roughness (5 nm vs. 15 nm), and better step coverage (95 % vs. 35 %). These experimental findings indicated that growth of Pt films from Pt(acac) 2 occurred under the kinetically-limited regime, whereas the deposition of Pt from (CH 3 ) 3 CH 3 CpPt was limited by the mass transport rate. Additionally, the temperature (4.2±293 K) dependence of the electrical resistivities (r) of Pt films was measured and the electron mean free paths were estimated. It was observed that r(T) deviated from Matthiessen's rule.

Articles you may be interested inResistivity change of the diamondlike carbon, deposited by focused-ion-beam chemical vapor deposition, induced by the annealing treatment Growth and nanostructure of conformal ruthenium films by liquid-source metalorganic chemical vapor deposition

A potentially manufacturable liquid source metalorganic chemical vapor deposition process was successfully applied to deposit Iridium films on a variety of substrates. The depositions of Ir were carried out in the temperature range of 300–450°C from tetrahydrofuran (THF) solution of CH3CpIrCOD (Cp=cyclopentadienyl, COD=cyclooctadiene) in a low-pressure, hot-wall reactor. Oxygen assisted pyrolysis of the precursor at 350°C resulted in a remarkably high Ir growth rate of 70 nm/min on IrO x /Si substrate. Additionally, Ir on Si exhibited a room-temperature resistivity of 10.2 µΩ cm. The as-deposited polycrystalline Ir films were highly reflecting, dense, and fine grained.

In this article we report the results of the scanning tunneling microscope study of the surface morphology of copper films grown by metalorganic chemical vapor deposition from the precursor Cu(tbaoac)2. Films ≈100 nm in thickness were grown by varying the reactor pressure. The images reveal the crucial role of the reactor pressure and growth rate on the morphology and grain growth of the films. Films grown at a low growth rate have a smooth surface with small well connected grains of ≈10–40 nm diameter with relatively lower resistivity, while films grown at higher growth rates have rougher surfaces and larger grain sizes of ≈10–100 nm diameter with poor connectivity that leads to higher resistivity. The correlation of the morphology with resistivity (ρ) and the temperature dependence of ρ in the range 300–4.2 K was investigated. Comparison with the ρ of pure bulk copper shows that these films have much higher resistivities. A large part of the high resistivity at room temperature arises from an enhanced temperature dependent part of ρ and is not due to an enhancement of the residual resistivity alone. The films exhibit deviations from Matthiessen’s rule. From a semi-quantitative analysis of the data using existing theories we could assign the large ρ as well as the temperature dependence of ρ to grain boundary scattering and surface scattering. However, for T>50 K we find that an extra temperature dependent ρ term which may be related to enhancement of electron-phonon interactions by the rough film surface is required.