An investigation into the growth of magnesium niobium oxide and lead magnesium niobate by liquid-injection MOCVD using a magnesium-niobium alkoxide precursor

• Published in: Advanced materials for optics and electronics 2000-05, Vol.10 (3-5), p.177-182
• Main Authors: Davies, Hywell O, Jones, Anthony C, Leedham, Timothy J, Wright, Peter J, Crosbie, Michael J, Lane, Penelope A, Steiner, Alexander, Bickley, Jamie
• Format: Article
• Language: English
• Subjects: double metal alkoxide; lead magnesium niobate; liquid injection MOCVD; magnesium niobium oxide; single-source precursors
• ISSN: 1057-9257; 1099-0712
• DOI: 10.1002/1099-0712(200005/10)10:3/5<177::AID-AMO410>3.0.CO;2-B

The double metal alkoxide Mg[Nb(OEt)6]2(2EtOH) has been in investigated as a single‐source precursor for the deposition of magnesium niobium oxide and lead magnesium niobate by liquid‐injection MOCVD. The presence of Pb(thd)2 (thd=2,2,6,6‐tetramethylheptane‐3,5‐dionate) has been shown to significantly influence the deposition chemistry of the Mg/Nb alkoxide precursor. In the absence of Pb(thd)2 and at low substrate temperatures (˜425 °C) the Mg : Nb ratio in the oxide film grown from Mg[Nb(OEt)6]2(2EtOH) is close to 1 : 2. At higher substrate temperatures (600 °C) the films are magnesium deficient, indicating partial decomposition of Mg[Nb(OEt)6]2(2EtOH). However, in the presence of Pb(thd)2, films grown from Mg[Nb(OEt)6]2(2EtOH) at low temperature (425 – 500 °C) contain no detectable Mg, whilst the 1 : 2 Mg : Nb ratio, required for Pb(Mg0.33Nb0.66)O3, is now obtained at higher substrate temperatures (600°C). This is attributed to the formation of a thermally‐stable Mg β‐diketonate species via a gas‐phase ligand exchange reaction between Pb(thd)2 and Mg[Nb(OEt)6]2(2EtOH). Copyright © 2000 John Wiley & Sons, Ltd.