Reduced-pressure MOCVD of highly crystalline BaTiO3 thin films

Buskirk, Peter C. Van; Gardiner, Robin; Kirlin, Peter S.; Nutt, Steven

doi:10.1557/jmr.1992.0542

Cited by 34 publications

(21 citation statements)

References 14 publications

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“…Second, the reported epitaxial growth is observed at a low temperature of 700°C. The growth temperature is 100°C lower than the temperatures used in comparable thermal MOCVD processes 8,9,12 including those using fluorinated precursors. A strong oxidant consisting of a mixture of 80% N 2 O and 20% O 2 was used to facilitate epitaxial growth at 700°C.…”

Section: Introductionmentioning

confidence: 92%

“…8,9,12 Epitaxial growth at lower temperatures has, however, been reported. Epitaxial growth at 680°C has been reported 10 by a plasma-enhanced MOCVD process, and epitaxial BaTiO 3 growth was also reported 13 at 650-700°C using the strong oxidant N 2 O+O 2 with a single source precursor for Ba and Ti, but this required a high precursor bubbler temperature ͑235°C͒.…”

Section: Introductionmentioning

confidence: 99%

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Low temperature deposition of epitaxial BaTiO3 films in a rotating disk vertical MOCVD reactor

Dhote

Meier

Towner

et al. 2005

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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Epitaxial BaTiO3 thin films were deposited on MgO (100) in a rotating disk vertical metalorganic chemical vapor deposition (MOCVD) reactor at 700°C. The metalorganic sources used were titanium tetraisopropoxide and the highly volatile fluorinated barium precursor (Ba(hfa)2∙pentaethyleneglycolethylbutylether(PEB)). To facilitate growth at the lower temperature while suppressing the formation of BaF2 impurity phases, a strong oxidant consisting of a mixture of 80% N2O and 20% O2 was employed. The BaTiO3 films deposited at 700°C are phase pure and show only BaTiO3 {001} x-ray diffraction peaks. The x-ray rocking curve full width at half maximum (FWHM) of the BaTiO3 (002) peak was 0.82°. The fourfold symmetry and coincident position of the {110} peaks for both the film and substrate confirms in-plane epitaxy of cube-on-cube orientation. The Φ-scan FWHM of the BaTiO3 film is 1.05°. The growth temperature in this work is lower than the temperatures used in most comparable thermal MOCVD epitaxial oxide processes for BaTiO3.

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Section: Introductionmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Low temperature deposition of epitaxial BaTiO3 films in a rotating disk vertical MOCVD reactor

Dhote

Meier

Towner

et al. 2005

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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“…[7] Another possible choice of precursors would be the metal chlorides, BiCl 3 and TiCl 4 . TiCl 4 is a common precursor in the CVD of TiO 2 , [8] while BiCl 3 has been used as the bismuth precursor in halide CVD of superconducting phases in the Bi±Sr±Ca±Cu±O system. [9] In the present investigation, the Bi 4 Ti 3 O 12 phase is deposited on single-crystalline a-Al 2 O 3 (012) substrates (lattice parameters a = 4.758 , c = 12.991 , c = 120) using chloride precursors.…”

Section: Methodsmentioning

confidence: 99%

MOCVD of Epitaxial BaTiO3 Films Using a Liquid Barium Precursor

Teren

Belot

Edleman

et al. 2000

Chem. Vap. Deposition

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Barium titanate (BaTiO 3 ) thin films are of interest for electronic and photonic devices because of the material's large dielectric constant and nonlinear optical coefficient. [1,2] A potential application for integrated optics is thin film waveguide electro-optic modulators. [3] For many of these applications, the films must be phase-pure, epitaxial, and defect free. Previously we, and other groups, have reported the deposition of high quality BaTiO 3 films using metal±organic chemical vapor deposition (MOCVD). [4±10] While MOCVD allows precise control of the precursor delivery rate, one of the difficulties has been the availability of Ba sources with sufficient vapor pressure, low melting point, and thermal-cycling stability. [11] Until now we have employed a fluorinated b-diketonate precursor, Ba(hfa) 2 ×tetraglyme (hfa = hexafluoroacetylacetonate). This precursor exhibits good volatility and can be used at temperatures of 110 C, which is 100 C lower than the more widely used Ba(thd) 2 (thd = tetramethylheptanedionate) compound. Ba(hfa) 2 ×tetraglyme, however, is a solid at useful growth temperatures, which leads to run-to-run variability in film composition resulting from a degradation in volatility, due to particle sintering effects. This has motivated the development of alternative barium liquid precursors for the CVD of BaTiO 3 , as well as other mixed-metal oxide compounds. [12±14] We evaluated a new low-melting Ba MOCVD precursor, Ba(hfa) 2 × pentaethyleneglycol ethyl butyl ether [Ba(hfa) 2 ×PEB]. This compound is one of a series of polyether complexes having the general formulae Ba(hfa) 2 ×RO(CH 2 CH 2 O) n R¢. [13] It has a melting point (m.p.) of 71 C, which is significantly lower than the 151 C m.p. of the tetraglyme complex. The volatility characteristics of the new precursor were evaluated using vacuum thermogravimetric analysis (TGA). As shown in Figure 1, the pentaethyleneglycol-based source sublimes at a rate similar to that of the solid tetraglyme under typical MOCVD film growth conditions (110±120 C/4 torr). We report here on the utilization of Ba(hfa) 2 ×PEB for the growth of epitaxial BaTiO 3 by MOCVD.Films were deposited over the temperature range 700± 800 C. At 800 C the deposition rate was 100 nm h ±1 . The composition of the films was analyzed using conventional h/2h X-ray diffraction (XRD) techniques. The XRD scans indicate that, for growth temperatures of 700±800 C, the BaTiO 3 films are phase-pure under optimal conditions (Fig. 2). The lattice constant, 4.012 , is somewhat larger

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“…Many deposition techniques have been developed to obtain films, for example, sputtering, 11) metal-organic chemical vapor deposition (MOCVD), 12) sol-gel processing 13,14) and laser ablation. 15,16) The oxygen partial pressure can be a dominant deposition parameter, obviously affecting the oxygen deficiency, deposition rate and other characteristics of oxide films in those film processes.…”

Section: Introductionmentioning

confidence: 99%

Effect of Oxygen Partial Pressure on Structure and Dielectric Property of BaTi2O5 Films Prepared by Laser Ablation

Wang

Goto

2007

Mater. Trans.

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BaTi 2 O 5 ferroelectric films were prepared on MgO (100) substrates by laser ablation at various oxygen partial pressures (P O2 ). The effect of P O2 on the orientation, composition, surface morphology and dielectric property of the films was investigated. The molar ratio of Ti to Ba was independent of P O2 , almost in agreement with the stoichiometric composition of BaTi 2 O 5 . The BaTi 2 O 5 films showed the orientation of (710) and (020) depending on P O2 . At P O2 ¼ 12:5 Pa, (020) oriented BaTi 2 O 5 film with an elongated granular and perpendicularly crossing texture was epitaxially grown on MgO (100) substrates. The BaTi 2 O 5 film prepared at P O2 ¼ 12:5 Pa exhibited a sharp permittivity maximum (" 0 % 2000) at 750 K.

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Reduced-pressure MOCVD of highly crystalline BaTiO₃ thin films

Cited by 34 publications

References 14 publications

Low temperature deposition of epitaxial BaTiO3 films in a rotating disk vertical MOCVD reactor

Low temperature deposition of epitaxial BaTiO3 films in a rotating disk vertical MOCVD reactor

MOCVD of Epitaxial BaTiO3 Films Using a Liquid Barium Precursor

Effect of Oxygen Partial Pressure on Structure and Dielectric Property of BaTi<SUB>2</SUB>O<SUB>5</SUB> Films Prepared by Laser Ablation

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