Fluidized Bed Chemical Vapor Deposition of Zirconium Nitride Films

Abstract

A fluidized bed-chemical vapor deposition (FB-CVD) process was designed and established in a two-part experiment to produce zirconium nitride barrier coatings on uranium-molybdenum particles for a reduced enrichment dispersion fuel concept. A hot-wall, inverted fluidized bed reaction vessel was developed for this process, and coatings were produced from thermal decomposition of the metallo-organic precursor tetrakis(dimethylamino)zirconium (TDMAZ) in highpurity argon gas. Experiments were executed at atmospheric pressure and low substrate temperatures (i.e., 500 to 550 K). Deposited coatings were characterized using scanning electron microscopy, energy dispersive spectroscopy, and wavelength dis-persive spectroscopy. Successful depositions were produced on 1 mm diameter tungsten wires and fluidized ZrO 2 -SiO 2 microspheres (185 to 250 µm diameter) with coating thicknesses ranging from 0.5 to 30 μm. The coating deposition rate was nominally estimated to be 0.04 ± 0.02 µm/h. The ZrN coating adhered to the microspheres, but there was a significant oxygen and possible carbon contamination.

Chemical Vapor Deposition of Zirconium Compounds: A Review

“…These properties make them attractive for such applications as cutting tools, optical coatings, microelectronic contacts, and diffusion barriers. When deposited by CVD, ZrN has been grown by either inorganic (ZrCl 4 -N 2 -H 2 or ZrCl 4 -NH 3 ) [124,125] or organometallic [64,123,[126][127][128][129][130][131] (e.g., Zr(N(CH 3 ) 2 ) 4 -NH 3 ) routes.…”

“…With applications in such diverse fields as radiological coatings, optics, and microelectronics, deposition of zirconium nitrides (ZrN, Zr 3 N 4 ) at low temperatures (<500 • C) and with a low halide contamination have been of interest [123]. To that end, research has been reported for the deposition of ZrN from zirconium amido complexes, such as tetrakis(diethylamino)zirconium (Zr(NEt 2 ) 4 ) [64,123,[127][128][129]151,152], tetrakis(dimethylamino) zirconium (Zr(NMe 2 ) 4 ) [128][129][130][131]152,153], and tetrakis(ethylmethylamino)zirconium (Zr(NEtMe) 4 ) [129,152]. Deposition of ZrN from these organometallic precursors can be accomplished as a single-source precursor (e.g., Zr(NMe 2 ) 4 alone) [127][128][129][130][131]151] or in the presence of ammonia [123,129,152,153], nitrogen, or hydrogen [128].…”

“…When used as single-source precursors, amido-containing zirconium complexes usually suffer from high carbon contamination [129,130], sometimes to such an extent that resulting deposits are described as carbonitrides [128]. Growth rates can also be very slow, for example, as low as 1.1 µm/day at 280 • C [131].…”

“…However, the reactivity of this reaction is high enough that premature deposition and consumption of reactants can occur [129]. Dividing the reaction into sequential pulses via atomic layer deposition (ALD) of Zr(NMe 2 ) 4 + NH 3 was recently demonstrated to produce ZrN coatings with minimal carbon and oxygen contamination, albeit at 0.3 um/day growth rate in a non-optimized system [153].…”

Structures, properties and applications of two-dimensional metal nitrides: from nitride MXene to other metal nitrides

“…VN [442] CrN [442] MoN [442] WN [442] W2N3 [172,460] Ammoniation of the MClx@salt powder followed by dissolution of the salt-template Mn3N2 [87] CrN [93] Ammoniation of the MOx@salt powder followed by dissolution of the salt-template V2N [122] W2N [122] TiN [93] NbN [93,457] MoN [122,458] Mo5N6 [174] MoN [466] Chemical vapor deposition TiN [467] ZrN [468,469] MoN [470] TaN [471] WN [472] Zr3N4 [473] Hf3N4 [473] GaN [474] InN [310] Conventional self-flux method (single crystals)…”