Combinatorial High-Vacuum Chemical Vapor Deposition of Textured Hafnium-Doped Lithium Niobate Thin Films on Sapphire

• Published in: Crystal growth & design 2011-01, Vol.11 (1), p.203-209
• Main Authors: Dabirian, Ali, Kuzminykh, Yury, Sandu, Silviu Cosmin, Harada, Scott, Wagner, Estelle, Brodard, Pierre, Benvenuti, Giacomo, Rushworth, Simon, Muralt, Paul, Hoffmann, Patrik
• Format: Article
• Language: English
• Subjects: Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Physics; Vacuum deposition
• ISSN: 1528-7483; 1528-7505
• DOI: 10.1021/cg1011583

Combinatorial high-vacuum chemical vapor deposition (HV-CVD) was used to identify the conditions required to obtain hafnium-doped lithium niobate thin films on sapphire {001} substrates. Niobium tetraethoxydimethylaminoethoxide (Nb(OEt)4(dmae)), lithium tert-butoxide (Li(OBu t )), and hafnium tert-butoxide (Hf(OBu t )4) were used as precursors. X-ray diffraction (XRD) and transmission electron microscopy (TEM) indicated that a single phase of textured {001} Hf-doped lithium niobate film was obtained under certain precursor flux conditions. The lithium content ([Li]/([Li] + [Nb])) of the textured film was estimated using Raman spectroscopy to be about 49 mol %. The presence of hafnium inside the films was confirmed by X-ray photoelectron spectroscopy (XPS) measurements, and the hafnium content of the textured film ([Hf]/([Hf] + [Nb])) was estimated to be about 3 mol %. XPS data confirmed that Hf and Nb, respectively, are in the +4 and +5 oxidation states inside the film. The film consists of nearly parallel {001} hafnium-doped lithium niobate columns with different in-plane orientations.