The
atomic layer deposition (ALD) of Ru using a metal–organic
precursor, tricarbonyl(trimethylenemethane)ruthenium [Ru(TMM)(CO)3] and O2 as a reactant is reported. The high vapor
pressure, thermal stability, and relatively small ligands of the precursor
facilitate efficient ALD. Typical self-limiting growth and an ALD
temperature window of 220–260 °C are observed along with
significantly high growth per cycle (GPC) (∼1.7 Å) and
short incubation cycles (∼6) at 220 °C. Density functional
theory calculations indicate that the high growth rate and self-limiting
behavior can be attributed to the characteristics of the trimethylenemethane
ligand. The as-grown polycrystalline films (average grain size ∼20
nm and negligible impurities) were evident from plan-view transmission
electron microscopy. The variation in film resistivity with increasing
film thickness and deposition temperature was investigated with and
without annealing. Films deposited at 260 °C show low resistivity
(∼12.9 μΩ cm), which further decreases (∼9.8
μΩ cm) postannealing at 500 °C. A thin Ru film is
successfully deposited with 100% step-coverage on a dual-trench structure
having an aspect ratio of ∼6.3 (minimum width: ∼15 nm).
The interfacial adhesion energy measured using the four-point bending
test exceeds 7 J m–2, regardless of the dielectric
material and annealing treatment. The Ru precursor permits enhanced
nucleation and GPC at relatively low deposition temperatures to construct
high-quality Ru films with significantly low resistivity using simple,
plasma-free techniques, and is suitable for the fabrication of emerging
Ru films to replace Cu-based interconnects.
Tantalum oxide films were deposited on Si substrates by chemical vapor deposition using the precursor Ta[N(CH3)2]5, and an oxidizing agent—O2, H2O, or NO. Temperatures ranged between 400 and 500 °C and total pressures between 10−3 and 9 Torr. NO did not lead to satisfactory film growth rates. Insignificant (<1 at. %) N and up to a few percent C are incorporated when O2 is the oxidant and the total pressure is in the Torr regime. In the milliTorr regime, the Ta2O5 films, grown using either O2 or H2O, contain readily detectable amounts of C and N. For the films grown with O2 in the Torr regime, leakage currents were significantly lowered when the flow rate of O2 increased from 100 to 900 sccm.
-AlzCu thin fti (-382 nm) are fabricated by melting and resolidi~ing A1/Cubilayers in the presence of a -3 nm A1203 passivating layer. X-ray Photoelectron Spectroscopy (XPS) measures a 1.0 eV shift of the Cu2p3i2 peak and a 1.6 eV shift of the valance band relative to metallic Cu upon AlzCu formation. Scanning Electron Microscopy (SEM) and Electron BackScattered Diffraction (EBSD) show that the AlzCu film is composed of 30-70pm wide and 10-25 mm long cellular grains with (110) orientation. The atomic composition of the fti as estimated by Energy Dispersive Spectroscopy (EDS) is 67k2% Al and 33fl% Cu.XPS scans of Alz03/A12CUtaken before and after air exposure indicate that the upper A12Culayers undergo further oxidation to A1203 even in the presence of -5 nm A1203. The majority of Cu produced from oxidation is believed to migrate below the A1203layers, based upon the lack of evidence for metallic Cu in the XPS scans. In contrast to A1./Cu passivated with A1203, meltinghesolidifying the A1/Cu-bilayer without A1203 results in phasesegragated dendritic fdm growth.
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