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The atomic layer deposition of copper metal thin films was achieved using a three precursor sequence entailing Cu(OCHMeCH2NMe2)2, formic acid, and hydrazine. A constant growth rate of 0.47−0.50 Å/cycle was observed at growth temperatures between 100 and 170 °C. The resulting films are high purity and have low resistivities.

Treatment of MCl 2 (M = Cr, Mn, Fe, Co, Ni) with 2 equiv of lithium metal and 1,4-di-tertbutyl-1,3-diazadiene ( tBu2 DAD) in tetrahydrofuran at ambient temperature afforded Cr( tBu2 DAD) 2 (38%), Mn( tBu2 DAD) 2 (81%), Fe( tBu2 DAD) 2 (47%), Co( tBu2 DAD) 2 (36%), and Ni( tBu2 DAD) 2 (41%). Crystal structure determinations revealed monomeric complexes that adopt tetrahedral coordination environments and were consistent with tBu2 DAD radical anion ligands. To evaluate the viability of M( tBu2 DAD) 2 (M = Cr, Mn, Fe, Co, Ni) as potential film growth precursors, thermogravimetric analyses, preparative sublimations, and solid-state decomposition studies were performed. Mn( tBu2 DAD) 2 is the most thermally robust among the series, with a solid-state decomposition temperature of 325 °C, a sublimation temperature of 120 °C/0.05 Torr, and a nonvolatile residue of 4.3% in a preparative sublimation. Thermogravimetric traces of all complexes show weight loss regimes from 150 to 225 °C with final percent residues at 500 °C ranging from 1.5 to 3.6%. Thermolysis studies reveal that all complexes except Mn( tBu2 DAD) 2 decompose into their respective crystalline metal powders under an inert atmosphere. Mn( tBu2 DAD) 2 may afford amorphous manganese metal upon thermolysis.

Atomic layer deposition (ALD) of ruthenium metal films is presented using (η4-2,3-dimethylbutadiene)(tricarbonyl)ruthenium [Ru(DMBD)(CO)3] with the coreactants 1,1-dimethylhydrazine, hydrazine, or tert-butylamine. The dependence of growth rate on precursor pulse lengths at 200 °C showed a saturative, self-limited behavior at ≥3.0 s for Ru(DMBD)(CO)3 and ≥0.1 s for 1,1-dimethylhydrazine. An ALD window was observed from 200 to 210 °C, with a growth rate of 0.42 Å/cycle. Films grown at 200 °C showed rms surface roughnesses of <1 nm. X-ray photoelectron spectroscopy of a 42 nm thick film grown at 200 °C revealed 90.6% ruthenium, 7.0% nitrogen, and 2.0% oxygen. Ruthenium films were deposited on patterned substrates with TiN surfaces using various treatments at 200 °C with 250 cycles. 42 nm thick ruthenium films grown at 200 °C were subjected to annealing studies under hydrogen and ammonia atmospheres at 400 °C, followed by rapid thermal annealing at 600 °C. These annealing procedures led to higher purity, more crystalline, and lower resistivity ruthenium films. The coreactants hydrazine and tert-butylamine were evaluated in ruthenium ALD trials using Ru(DMBD)(CO)3. Hydrazine gave a growth rate of 0.42 Å/cycle within a 200–205 °C ALD window, whereas tert-butylamine gave a growth rate of 0.25 Å/cycle at 200 °C.

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