Titanium Phosphide Coatings from the Atmospheric Pressure Chemical Vapor Deposition of TiCl₄ and RPH₂ (R = t-Bu, Ph, Cy^Hex)

Abstract

Atmospheric pressure chemical vapor deposition of titanium phosphide coatings was achieved on glass substrates from the reaction of TiCl4 and RPH2 (R = t-Bu, Ph, Cyhex) at 450−550 °C. The coatings show good uniformity, surface coverage, and adherence; they passed the Scotch brand tape test and could not be scratched with a brass scalpel. The leading edge of the titanium phosphide films was a deep blue while the bulk of the film was reflective and silver. Growth rates were on the order of 1 μm min-1 at 550 °C. The films were crystalline, single phase with a hexagonal cell of a = 3.49(1) Å and c = 11.70(1) Å. Scanning electron microscopy (SEM) revealed surface morphologies consistent with an island growth mechanism. X-ray photoelectron spectroscopy (XPS) binding energy shifts were at 454.6 eV for Ti2p and at 128.6 eV for P2p. Energy-dispersive X-ray analysis (EDXA) and electron probe studies gave elemental ratios that were in agreement indicating in most cases slightly P-rich films, TiP1.2, with negligible chlorine incorporation. Raman spectra exhibited bands at 245, 320, and 410 cm-1. Sheet resistance measurements showed typically 10−120 mΩ cm, indicating good conductivity. Rutherford backscattering showed a bulk composition of TiP1.2. Optically, the films showed high reflectivity at 1000 nm and showed 5−25% total transmission from 300 to 800 nm. Contact angle measurements were in the range 40−50° for the as made films these showed little change after 30 min of irradiation at 254 nm. All of the films showed negligible photocatalytic activity in the destruction of an overlayer of stearic acid.

Atmospheric Pressure Chemical Vapour Deposition of TiCl4 and tBuAsH2 to Form Titanium Arsenide Thin Films

“…A thickness gradient is observed moving along the film from the end nearest the precursor inlet (thickest); we therefore conclude that the different colours relate not to regions of different composition, but to regions of different thickness. Indeed, these blue and gold films are consistent with those previously reported on the leading edge of silver TiP films, [15] with both TiAs and TiP thin films different in visual appearance to metallic gold/purple thin films of TiN. [8] The films were highly reflective and did not show any changes in visual appearance after approximately one year's storage in air.…”

“…[12] Indeed, group 15 organoprecursors have demonstrated themselves as successful alternatives to the group 15 hydrides in the deposition of a variety of phosphorus compounds. [13] Recently we reported the first dual-source deposition of TiP films on glass substrates by the APCVD reaction of TiCl 4 with tBuPH 2 , [14] from the reaction of TiCl 4 with a variety of primary phosphanes (RPH 2 where R = Ph, tBu and Cy hex ) [15] and from the reaction of [Ti(NMe 2 ) 4 ] with Cy hex PH 2 . [16] Thereafter, we extended the methodology to deposit GeP using both primary and secondary phosphanes, [17,18] and also to deposit NbP, [19] TaP, [20] CrP, [21] MoP [22] and VP thin films.…”

Chemical vapour deposition of group Vb metal phosphide thin films

“…15 We have shown that TiP films can be made from the APCVD reaction of TiCl 4 and Cy hex PH 2 . 12 Here we report the first APCVD study of group Vb phosphides from the reaction of volatile halide precursors and Cy hex PH 2 . This paper also describes the effect of process conditions on the resultant films.…”

“…Winter et al have demonstrated a low pressure route (400 -600 C) to thin NbP films using a single-source precursor formed from the reaction of niobium(V) chloride and cyclohexylphosphine (Cy hex PH 2 ) but this precursor showed significant decomposition at its sublimation temperature. 10 It has also been shown that the reaction of a metal chloride with a primary organophosphine (RPH 2 ) provides a readily accesible low temperature route to metal phosphides [11][12][13][14] and recently this has been demonstrated for the production of -TaP from the reaction of TaCl 5 with Cy hex PH 2 . 15 We have shown that TiP films can be made from the APCVD reaction of TiCl 4 and Cy hex PH 2 .…”

Atmospheric‐Pressure CVD of Vanadium Phosphide Thin Films from Reaction of Tetrakisdimethyl‐amidovanadium and Cyclohexylphosphine

“…[8] Recently, thin films of titanium phosphide, [9] tantalum phosphide, [10] and molybdenum phosphide [11] have been deposited from the reaction of metal halide with cyclohexylphosphine (Cy hex PH 2 ) using atmospheric-pressure (AP) CVD conditions. However, when extending this methodology to the reaction of VCl 4 with Cy hex PH 2 , it was concluded that film deposition required higher process temperatures than the other group Vb elements.…”