000205617 001__ 205617
000205617 005__ 20190317000121.0
000205617 022__ $$a0040-6090
000205617 02470 $$2ISI$$a000346053900016
000205617 0247_ $$2doi$$a10.1016/j.tsf.2014.09.073
000205617 037__ $$aARTICLE
000205617 245__ $$aEvaluation of niobium dimethylamino-ethoxide for chemical vapour deposition of niobium oxide thin films
000205617 269__ $$a2014
000205617 260__ $$bElsevier$$c2014$$aLausanne
000205617 300__ $$a8
000205617 336__ $$aJournal Articles
000205617 520__ $$aChemical vapour deposition (CVD) processes depend on the availability of suitable precursors. Precursors that deliver a stable vapour pressure are favourable in classical CVD processes, as they ensure process reproducibility. In high vacuum CVD (HV-CVD) process vapour pressure stability of the precursor is of particular importance, since no carrier gas assisted transport can be used. The dimeric Nb-2(OEt)(10) does not fulfil this requirement since it partially dissociates upon heating. Dimethylamino functionalization of an ethoxy ligand of Nb(OEt)(5) acts as an octahedral field completing entity and leads to Nb(OEt)(4)(dmae). We show that Nb(OEt) 4(dmae) evaporates as monomeric molecule and ensures a stable vapour pressure and, consequently, stable flow. A set of HV-CVD experiments were conducted using this precursor by projecting a graded molecular beam of the precursor onto the substrate at deposition temperatures from 320 degrees C to 650 degrees C. Film growth rates ranging from 8 nm.h(-1) to values larger than 400 nm.h(-1) can be obtained in this system illustrating the high level of control available over the film growth process. Classical CVD limiting conditions along with the recently reported adsorption-reaction limited conditions are observed and the chemical composition, and microstructural and optical properties of the films are related to the corresponding growth regime. Nb(OEt)(4)(dmae) provides a large process window of deposition temperatures and precursor fluxes over which carbon-free and polycrystalline niobium oxide films with growth rates proportional to precursor flux are obtained. This feature makes Nb(OEt)(4)(dmae) an attractive precursor for combinatorial CVD of niobium containing complex oxide films that are finding an increasing interest in photonics and photoelectrochemical water splitting applications. The adsorption-reaction limited conditions provide extremely small growth rates comparable to an atomic layer deposition (ALD) process indicating that HV-CVD has the potential to be an alternative to ALD for growth of ultrathin films on low aspect ratio substrates. (C) 2014 Elsevier B.V. All rights reserved.
000205617 6531_ $$aMetal-organic precursors
000205617 6531_ $$aChemical vapour deposition
000205617 6531_ $$aCombinatorial film deposition
000205617 6531_ $$aNiobium oxide
000205617 6531_ $$aNiobium alkoxide
000205617 700__ $$0242061$$g174232$$uEcole Polytech Fed Lausanne, Lab Photon Mat & Characterizat, CH-1015 Lausanne, Switzerland$$aDabirian, Ali
000205617 700__ $$0(EPFLAUTH)176629$$g176629$$aKuzminykh, Yury
000205617 700__ $$u3D Oxides, F-01630 St Genis Pouilly, France$$aWagner, Estelle
000205617 700__ $$0241786$$g117763$$u3D Oxides, F-01630 St Genis Pouilly, France$$aBenvenuti, Giacomo
000205617 700__ $$aRushworth, Simon
000205617 700__ $$aHoffmann, Patrik$$uEcole Polytech Fed Lausanne, Lab Photon Mat & Characterizat, CH-1015 Lausanne, Switzerland$$g113150$$0241019
000205617 773__ $$j571$$tThin Solid Films$$q94-101
000205617 8564_ $$uhttps://infoscience.epfl.ch/record/205617/files/Dabirian-TSF2014.pdf$$zPublisher's version$$s2413708$$yPublisher's version
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000205617 980__ $$aARTICLE