Reflection high-energy electron diffraction analysis of polycrystalline films with grain size and orientation distributions

Analysis of biaxial texture of MgO films grown by ion-beam-assisted deposition ͑IBAD͒ has been performed using a quantitative reflection high-energy electron diffraction ͑RHEED͒ based method. MgO biaxial texture is determined by analysis of diffraction spot shapes from single RHEED images, and by measuring the width of RHEED in-plane rocking curves for MgO films grown on amorphous Si 3 N 4 by IBAD using 750 eV Ar ϩ ions, at 45°incidence angle, and MgO e-beam evaporation. RHEED-based biaxial texture measurement accuracy is verified by comparison with in-plane and out-of-plane orientation distribution measurements made using transmission electron microscopy and x-ray rocking curves. In situ RHEED measurements also enable the analysis of the evolution of the biaxial texture which narrows with increasing film thickness. RHEED-based measurements of IBAD MgO biaxial texture show that the minimum in-plane orientation distribution depends on the out-of-plane orientation distribution, and indicates that the minimum obtainable in-plane orientation on distribution is 2°.

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“…8 These calculations predict that spot shapes are sensitive to the film microstructure, as shown in Fig. 1͑a͒.…”

Section: Experimental Approach and Model-based Analysismentioning

confidence: 99%

Reflection high-energy electron diffraction experimental analysis of polycrystalline MgO films with grain size and orientation distributions

Brewer

Atwater

Groves

et al. 2003

Journal of Applied Physics

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“…At film thickness ∼ 3 nm, the RHEED pattern evolved into spots. Using single-image analysis of the RHEED patterns from the diffraction spots, determined in situ, they performed quantitative analysis of the biaxially textured MgO films ranging from ∼ 3-nm to 11-nm thick (Brewer et al 2001a;Brewer and Atwater 2002). Later, the MgO film was used as a template layer to grow biaxially textured ferroelectric Ba x Pb 1−x TiO 3 thin films (Brewer et al 2004).…”

Section: Mgo Film On Amorphous Substrate Si 3 N 4 On Si(001)mentioning

confidence: 99%

“…Later, the MgO film was used as a template layer to grow biaxially textured ferroelectric Ba x Pb 1−x TiO 3 thin films (Brewer et al 2004). The out-of-plane orientation distribution and the in-plane orientation distribution were calculated using a kinematic electron diffraction model, assuming film-related parameters that included angular ranges of both out-of-plane orientation distribution and in-plane orientation distribution, effective grain sizes, and electron penetration depth (Brewer et al 2000(Brewer et al , 2001bHartman et al 2002). Experimentally, the diffraction spot shape provided the information.…”

Section: Mgo Film On Amorphous Substrate Si 3 N 4 On Si(001)mentioning

confidence: 99%

RHEED Transmission Mode and RHEED Pole Figure

Wang

2013

RHEED Transmission Mode and Pole Figures

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In the last chapter, we presented the principles of x-ray diffraction and the construction of a pole figure, particularly the pole figure constructed from the diffraction patterns obtained by an area detector. In this chapter, we describe the similarities and differences between reflection high-energy electron diffraction (RHEED) transmission mode and x-ray diffraction. Detailed descriptions of the diffraction space characteristics of RHEED transmission for a variety of crystal textures are given. We discuss kinematic simulations of RHEED patterns and the construction of RHEED pole figures from RHEED patterns. The relationship between RHEED pole figures and the orientation distribution function of biaxial texture is presented with examples. X-Ray Diffraction vs RHEEDMost thin films grown by common deposition techniques such as physical vapor deposition or chemical vapor deposition are not single crystals. Single crystals are grown only under specific favorable conditions. A major technique used for texture structure characterization is the x-ray pole figure. The typical photon energy used in x-ray diffraction is 8,048 eV (Cu K α ), while tens of kiloelectron volt electrons are used for reflection high-energy electron diffraction (RHEED). Here we discuss the similarities and differences between x-ray diffraction and the RHEED transmission mode. Strength of scattering cross sectionThe scattering cross section for electrons in solids is orders of magnitude higher than that for x-rays. For example, the total elastic electron scattering from Mo at 10 keV incident electron energy is on the order of 10 −19 m 2 (Browning 1991). In the energy range of 1-100 keV, the cross-section scales as E −0.5 in the low-energy regime and E −1 and Z 1.33 in the high-energy regime, where E is in units of keV and Z is the atomic number of an atom. For 1 keV photon, the total photon cross section from Pb is on the order of 10 −22 m 2 (Hubbell et al. 1975). The stronger scattering cross section of electrons provides a stronger electron diffraction signal from ultrathin films and nanostructures.

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“…tion distributions. 13 The PBT films grown under the same conditions on biaxially textured MgO with a homoepitaxial layer show sharp diffraction spots characteristic of narrow out-of-plane orientation distributions (⌬ = 3°FWHM for MOCVD and ⌬ = 4°FWHM for sol gel, where ⌬ represents the out-of-plane orientation distribution FWHM). All the diffraction patterns in Fig.…”

Section: A Biaxially Textured Mgo Substratementioning

confidence: 99%

“…The biaxial texture of the IBAD MgO templates and of the heteroepitaxial ferroelectric films were measured using a RHEEDbased technique. 13,8 The quality of the ferroelectric/MgO interface and the film structure were examined with TEM. The ferroelectric behavior of these films was probed using dynamic contact mode electrostatic force microscopy (DC-EFM).…”

Section: B Film Characterizationmentioning

confidence: 99%

Growth of biaxially textured BaxPb1−xTiO3 ferroelectric thin films on amorphous Si3N4

Brewer

Boyd

El‐Naggar

et al. 2004

Journal of Applied Physics

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We prepared highly aligned, biaxially textured Ba x Pb 1−x TiO 3 (PBT) on amorphous Si 3 N 4 by using an ion-beam-assisted deposited MgO as a template layer. PBT was deposited on a biaxially textured MgO using sol-gel synthesis, metal-organic chemical-vapor deposition, and molecular beam epitaxy. The biaxial texture of the PBT was inherited from the MgO template. The reflection high-energy electron diffraction (RHEED) and cross-section transmission electron microscopy (TEM) experiments suggest that exposure of the MgO template to atmospheric moisture before PBT heteroepitaxy resulted in a significant narrowing of the PBT in-plane orientation distribution. The microstructures of the biaxially textured PBT films were analyzed by x-ray diffraction, RHEED, and TEM. The dynamic contact mode electrostatic force microscopy polarization hysteresis loops confirmed that these films are ferroelectric.

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Reflection high-energy electron diffraction analysis of polycrystalline films with grain size and orientation distributions

Cited by 7 publications

References 6 publications

Reflection high-energy electron diffraction experimental analysis of polycrystalline MgO films with grain size and orientation distributions

Reflection high-energy electron diffraction experimental analysis of polycrystalline MgO films with grain size and orientation distributions

RHEED Transmission Mode and RHEED Pole Figure

Growth of biaxially textured BaxPb1−xTiO3 ferroelectric thin films on amorphous Si3N4

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