Synthesis and Characterization of Volatile, Thermally Stable, Reactive Transition Metal Amidinates

Abstract

A series of homoleptic metal amidinates of the general type [M(R-R'AMD)(n)](x) (R = (i)Pr, (t)Bu, R' = Me, (t)Bu) has been prepared and structurally characterized for the transition metals Ti, V, Mn, Fe, Co, Ni, Cu, Ag, and La. In oxidation state 3, monomeric structures were found for the metals Ti(III), V(III), and La(III). Bridging structures were observed for the metals in oxidation state 1. Cu(I) and Ag(I) are held in bridged dimers, and Ag(I) also formed a trimer that cocrystallized with the dimer. Metals in oxidation state 2 occurred in either monomeric or dimeric form. Metals with smaller ionic radii (Co, Ni) were monomeric. Larger metals (Fe, Mn) gave monomeric structures only with the bulkier tert-butyl-substituted amidinates, while the less bulky isopropyl-substituted amidinates formed dimers. The new compounds were found to have properties well-suited for use as precursors for atomic layer deposition (ALD) of thin films. They have high volatility, high thermal stability, and high and properly self-limited reactivity with molecular hydrogen, depositing pure metals, or water vapor, depositing metal oxides.

Synthesis and Characterization of Ruthenium Amidinate Complexes as Precursors for Vapor Deposition

“…(11) Ru ( The structure of Ru( i Pr-Me-amd) 3 is a distorted trigonal prism with dihedral angles of 97.5, 97.5, 82.5°. The geometry of the three Ru-N-C-N four membered rings is essentially planar with a mean deviation of 0.0164-0.0165 Å, which was also found in the previously reported structures of the transition metal amidinates [17]. The average bite angle is 62.8°, which is quite similar to that of V( i Pr-Me-amd) 3 (63.5°) [17].…”

“…Some volatile and thermally stable metal amidinates [16,17] have been found to be effective for ALD and CVD of metals (Fe, Co, Ni, Cu, Ag, Ru) [18], transition metal oxides (MnO, FeO,CoO, NiO, Cu 2 O) [19], lanthanide oxides (La 2 O 3 , LaAlO 3 [20], PrAlO 3 [21], Sc 2 O 3 [22], Y 2 O 3 [23], GdScO 3 [24], Lu 2 O 3 [25]), nitrides (Fe x N [26], Co x N [27], Ni x N [28], Cu 3 N [29]). These metal amidinate precursors provide several benefits compared with other types of ALD precursors.…”

Filling Narrow Trenches by Iodine-Catalyzed CVD of Copper and Manganese on Manganese Nitride Barrier/Adhesion Layers

“…These compounds were synthesized by methods similar to those described previously. (11,12) To prepare manganese nitride by CVD, the manganese precursor was evaporated from the liquid in a bubbler at a temperature of 90 °C into a 60 sccm flow of highly purified nitrogen (concentrations of water and oxygen less than 10 -9 relative to The thickness of manganese nitride was measured by X-ray reflectometry (XRR), and the thickness of copper was measured by scanning electron microscopy (SEM). Atomic force microscopy (AFM) was used to evaluate the surface morphology of the manganese nitride film.…”

Direct-Liquid-Evaporation Chemical Vapor Deposition of Nanocrystalline Cobalt Metal for Nanoscale Copper Interconnect Encapsulation

“…23,26 Tetradecane (Millipore Sigma Chemical Co.) was distilled from sodium to remove moisture before use. All chemical operations were conducted in a glove box with a nitrogen atmosphere.…”