Titanium aminoalkoxides: [Ti(OCH2CH2O)(OCH2CH2NMe2)2]2 Ti(OiPr)2(OCH2CH2NMe2)2, Ti(OCH2CH2NMe2)4 have been applied as precursors for the Ti-containing film growth.
Dimethylaminoethoxide ligand (dmae = OCH2CH2NMe2) stabilized titanium alkoxide complex [Ti(OPri)3(dmae)] was synthesized and characterised. [Ti(OPri)3(dmae)] exists in solution at room temperature as a mixture of monomer and dimer(s), with monomer predominating at elevated temperatures.
[Ti(OPri)3(dmae)] is volatile and was reported to be applicable as precursor for the growth of TiO2 layers by MOCVD.
Ti(OPri)3(dmae)] was applied as Ti precursor for the growth of TiO2 thin films by liquid injection MOCVD at 300-450°C deposition temperature. No N contamination
was detected in the layers, however trace C impurity was present at levels 2.9-7.7, according to Auger electron spectroscopy measurements.[i]
[i] A.C. Jones, T.J. Leedham, P.J. Wright, M.J. Crosbie, K.A. Fleeting, D.J. Otway, P. O'Brien, M.E. Pemble, J. Mater. Chem., 1998, 8, 1773-1777, DOI: 10.1039/A802933D, « Synthesis and characterisation of two novel titanium isopropoxides stabilised with a chelating alkoxide: their use in the liquid injection MOCVD of titanium dioxide thin films », https://pubs.rsc.org/en/content/articlehtml/1998/jm/a802933d
Titanium bis(dimethylaminoethoxide) bis(isopropoxide) [Ti(OPri)2(dmae)2] was synthesized and characterized; it was found that [Ti(OPri)2(dmae)2] is predominantly monomeric in solution, presumably with pseudo-octahedral coordination at the metal centre.
[Ti(OPri)2(dmae)2] is volatile and was reported to be useful as precursor for the deposition of TiO2 layers by MOCVD and ALD.
[Ti(OPri)2(dmae)2] complex was tested as precursor for the liquid injection MOCVD growth of TiO2 layers at 300-450°C temperatures.
AES measurements revealed no N impurity in the films, however trace C contamination was present at levels 2.9 to 7.7.[i]
[i] A.C. Jones, T.J. Leedham, P.J. Wright, M.J. Crosbie, K.A. Fleeting, D.J. Otway, P. O'Brien, M.E. Pemble, J. Mater. Chem., 1998, 8, 1773-1777, DOI: 10.1039/A802933D, « Synthesis and characterisation of two novel titanium isopropoxides stabilised with a chelating alkoxide: their use in the liquid injection MOCVD of titanium dioxide thin films », https://pubs.rsc.org/en/content/articlehtml/1998/jm/a802933d
[Ti(OPri)2(dmae)2] was applied as Ti precursor (with H2O as co-precursor) for the deposition of TiO2 layers on Si(100) substrates by ALD. ALD process of TiO2 growth using [Ti(OPri)2(dmae)2] as precursor was found to be self-controlled at temperatures of 100-300°C. XRD, XPS, TEM, AFM and UV spectrometry were used to study the crystallinity, chemical composition, thickness and morphology of the deposited TiO2 films. The surface morphology of the TiO2 layers was smooth and uniform at growth temperatures below 300°C. TiO2 layers grown at 400°C had preferred orientation toward the [101] direction.[i]
[i] J.P. Lee, M.H. Park, T.-M. Chung, Y.-S. Kim, M.M. Sung, Bull. Korean Chem. Soc., 2004 Vol.25, Iss.4, p.475-479, « Atomic Layer Deposition of TiO2 Thin Films from Ti(OiPr)2(dmae)2 and H2O « , https://doi.org/10.5012/bkcs.2004.25.4.475
Titanium tetrakis(dimethylaminoethoxide) [Ti(OCH2CH2NMe2)4], or Ti(dmae)4], a more coordinatively saturated Ti precursor, was synthesized and characterized by 1 H variable temperature NMR and mass spectrometry. In the liquid state Ti(dmae)4 exists as a monomer.
Ti(dmae)4 is volatile and was reported to be applicable as precursor for the growth of Ti-contaning layers, for example (Ba,Sr)TiOx thin films.
Titanium tetrakis(dimethylaminoethoxide) Ti(dmae)4 was applied as Ti precursor (combined with Ba(thd)2(PMDT) and Sr(thd)2-PMDT (PMDT=pentamethyldiethylenetriamine))
for the growth of barium strontium titanate (Ba,Sr)TiOx (BST) thin films by direct liquid injection MOCVD. The amount of Ti incorporation was substantially higher with Ti(dmae)4
as precursor than using Ti(OiPr)2(thd)2 or Ti(thd)2(mpd) (mpd = methylpentanediol) as Ti sources for BST growth. At a deposition temperatures 420–500 °C the incorporation of Ba and Sr into the BST film was almost constant (Ba/(Ba+Sr)=0.5). With new
Ti precursor Ti(dmae)4, the hump and the hazy appearance was not detected in the grown BST films (unlike layers grown with previous Ti precursors Ti(OiPr)2(thd)2, Ti(thd)2(mpd)). The step coverage and properties of BST films obtained using Ti(dmae)4 as Ti
source were studied.[i]
[i] J.-H. Lee, J.-Y. Kim, J. Vacuum Sci. Tech. A 17, 3033 (1999); « Metalorganic chemical vapor deposition of barium strontium titanate thin films with a more coordinatively saturated Ti precursor, Ti(dmae)4 (dmae=dimethylaminoethoxide) », doi.org/10.1116/1.582001, avs.scitation.org/doi/abs/10.1116/1.582001