Low-temperature CVD of iron, cobalt, and nickel nitride thin films from bis[di(tert-butyl)amido]metal(II) precursors and ammonia

Abstract

Thin films of late transition metal nitrides (where the metal is iron, cobalt, or nickel) are grown by low-pressure metalorganic chemical vapor deposition from bis[di(tert-butyl)amido]metal(II) precursors and ammonia. These metal nitrides are known to have useful mechanical and magnetic properties, but there are few thin film growth techniques to produce them based on a single precursor family. The authors report the deposition of metal nitride thin films below 300 °C from three recently synthesized M[N(t-Bu)2]2 precursors, where M = Fe, Co, and Ni, with growth onset as low as room temperature. Metal-rich phases are obtained with constant nitrogen content from growth onset to 200 °C over a range of feedstock partial pressures. Carbon contamination in the films is minimal for iron and cobalt nitride, but similar to the nitrogen concentration for nickel nitride. X-ray photoelectron spectroscopy indicates that the incorporated nitrogen is present as metal nitride, even for films grown at the reaction onset temperature. Deposition rates of up to 18 nm/min are observed. The film morphologies, growth rates, and compositions are consistent with a gas-phase transamination reaction that produces precursor species with high sticking coefficients and low surface mobilities.

Atomic Layer Deposition of Nickel Nitride Thin Films using NiCl2(TMPDA) and Tert‐Butylhydrazine as Precursors

“…No distinct signals of a Ni–N bond were detected, suggesting that the film has the structure of an interstitial compound where the nitrogen atoms occupy specific interstitial sites in the Ni metal host. Similar spectra have been shown for CVD Ni x N and for ALD Ni deposited with NH 3 plasma . The measured Ni 2p peak overlapped almost completely with a Ni metal reference.…”

Unconventional Nickel Nitride Enriched with Nitrogen Vacancies as a High‐Efficiency Electrocatalyst for Hydrogen Evolution

“…The predominance of Ni <1+ in Ni 3 N 1− x /NF suggested that the electron density of a considerable fraction of Ni atoms was affected by the existence of nitrogen vacancies. Moreover, the peak at 398.0 eV ascribed to the NNi bonding was observed for both Ni 3 N/NF and Ni 3 N 1− x /NF in the high‐resolution N 1s XPS spectra (Figure b), and a peak centered at around 399.9 eV (denoted as V N ) was also revealed for Ni 3 N 1− x /NF. The observation of this extra peak at higher binding energy suggested the reduction of negative charges of nitrogen atoms and further verified the formation of nitrogen vacancies in Ni 3 N 1− x /NF, similar to the variation of XPS signals of oxygen in the oxide nanomaterials with oxygen vacancies .…”

Synthesis and Characterization of Strontium N,N-Dimethylaminodiboranates as Possible Chemical Vapor Deposition Precursors

“…The synthesis of strontium N,N-dimethylaminodiboranate (DMADB) complexes with other coordinated Lewis bases can be achieved by treating the thf adduct 3 with either a stoichiometric amount or an excess of the desired Lewis base. Thus, adding 1,2-dimethoxyethane (dme), bis(2-methoxyethyl) ether (diglyme), or N,N,N′,N′-tetramethylethylenediamine (tmeda) to 3 in thf affords the new compounds Sr-(H 3 BNMe 2 BH 3 ) 2 (dme) 2 (4), Sr(H 3 BNMe 2 BH 3 ) 2 (diglyme) (5), and Sr(H 3 BNMe 2 BH 3 ) 2 (tmeda) (6), respectively, in greater than 60% yields.…”

“…Binary and higher oxides of the alkaline-earth (group 2) metals have many technological uses, both as bulk materials and as thin films. For example, strontium is a key component in advanced materials such as high-temperature superconductors, dielectrics and ferroelectrics, nonlinear optical materials, and colossal magnetoresistive materials. − Thin films of these materials can generally be deposited by physical vapor deposition (PVD) methods such as sputtering, but these methods have some limitations. − For example, PVD has difficulty coating or filling deeply recessed features uniformly, which is one of the process requirements in the fabrication of certain microelectronic circuit elements such as interconnects and trench capacitors. This drawback arises because PVD generates atomic species with high sticking coefficients, which form a film as soon as they encounter the surface, thus giving “line of sight” coatings. , Chemical vapor deposition (CVD), on the other hand, can provide uniform coatings even in recessed features with high aspect ratios because the molecular precursors used in CVD can undergo many adsorption/desorption events before they react to form a film …”

“…Figure 6. Molecular structure of [Sr(BH 3 NMe 2 BH 3 ) 2 (tmeda)] 2(6). Ellipsoids are drawn at the 30% probability level, except for the hydrogen atoms, which are represented as arbitrarily sized spheres.…”