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The sealing mechanism of silicon bonding interfaces is reported as a function of annealing temperature. Details of the structural and chemical interface evolution are obtained for hydrophilic silicon/silicon and silicon/silicon dioxide wafer bonding, using x-ray reflectivity and infrared spectroscopy. A two-step mechanism is demonstrated: first a partial sealing of the interface driven by cross-wafer silanol bond condensation and second a water evacuation via oxide formation at the silicon oxide interface. [ABSTRACT FROM AUTHOR]

This article deals with strain relaxation in SmNiO3 epitaxial films deposited by chemical vapor deposition on SrTiO3 substrates. Thanks to x-ray reciprocal space mapping, we demonstrate that the strain relaxation is driven both “chemically” and “mechanically” by the formation of oxygen vacancies and misfit dislocations, respectively. Besides, a careful interpretation of the resistivity measurements allows us to highlight a correlation between the formation of oxygen vacancies, the stabilization of Ni3+, and the metal-insulator transition in the SmNiO3 films. Furthermore, using coplanar and grazing incidence diffraction, the shape of the strain gradient within the films is retrieved. This latter is calculated using a versatile scattering model involving B-spline functions. Finally, particular planar faults (Ruddlesden–Popper faults) that give rise to extended diffuse scattering on transverse scans are analyzed using a recent phenomenological model. [ABSTRACT FROM AUTHOR]

The structure of ultrathin epitaxial Pr2O3 films on Si(111) was studied by synchrotron radiation-grazing incidence x-ray diffraction. The oxide film grows as hexagonal Pr2O3 phase with its (0001) plane attached to the Si(111) substrate. The hexagonal (0001) Pr2O3 plane matches the in-plane symmetry of the hexagonal Si(111) surface unit cell by aligning the (10&1bar;0)Pr2O3 along the (11&2bar;) Si directions. The small lattice mismatch of 0.5% results in the growth of pseudomorphic oxide films of high crystalline quality with an average domain size of about 50 nm. The critical thickness tc for pseudomorphic growth amounts to 3.0± 0.5 nm. The relaxation of the oxide film from pseudomorphism to bulk behavior beyond tc causes the introduction of misfit dislocations, the formation of an in-plane small angle mosaicity structure, and the occurence of a phase transition towards a (111) oriented cubic Pr2O3 film structure. The observed phase transition highlights the influence of the epitaxial interface energy on the stability of Pr2O3 phases on Si(111). A mechanism is proposed which transforms the hexagonal (0001) into the cubic (111) Pr2O3 epilayer structure by rearranging the oxygen network but leaving the Pr sublattice almost unmodified. [ABSTRACT FROM AUTHOR]

The strain relaxation in SmNi[O.sub.3] epitaxial films deposited by chemical vapor deposition on SrTi[O.sub.3] substrates is studied. A phenomenological model is used for particular planar faults that give rise to extended diffuse scattering on transverse scans.

The structure of ultrathin epitaxial Pr2O3 films on Si(111) is studied by synchrotron radiation-grazing incidence x-ray diffraction. The oxide film grows as hexagonal Pr2O3 phase with its (0001) plane attached to the Si(111) substrate.

Direct silicon wafer bonding is an attractive way to build up stacked structures. For applications, defect free bonding is required whatever the post bonding processes, which can include thermal treatment. Direct bonding processes are usually applied using hydrophilic surfaces. Thus water trapped at bonding interfaces can induce low temperature oxidation, which is a source of gas and bonding defects. The aim of this paper is to compare the efficiencies of various H2O diffusion barriers, which can be elaborated onto silicon wafers before bonding. Behaviors of thin thermal silicon oxide, thermal silicon nitride and plasma induced silicon oxynitride capping layers have been evaluated and compared to a chemical oxide layer standard for low temperature annealing. The efficient role of thermal oxide, nitride or oxynitride layer as a H2O diffusion barrier has been pointed out. [ABSTRACT FROM AUTHOR]

The growth of Pr2O3 on Si(001) for film thicknesses up to 3 nm was studied in situ in ultrahigh vacuum without exposure to ambient by x-ray reflectivity, grazing incident x-ray diffraction, and angle-resolved x-ray photoelectron spectroscopy using synchrotron radiation. The electron density and chemical composition profiles as well as the in-plane superstructure deduced from the present analysis reveal the development of a 0.5 nm thick transition layer at the interface that exhibits a cubic Pr2O3 structure and is commensurate to the Si substrate. This layer is overgrown by disordered Pr silicate. [ABSTRACT FROM AUTHOR]

Abstract: The initial stages of the molecular beam epitaxy growth of Pr2O3 on atomically clean Si(111) have been studied in ultra-high vacuum by low energy electron diffraction and scanning tunneling microscopy. At very low coverages, the oxide nuclei decorate the dimer rows of the silicon surface as line structure forming open triangles. At higher coverages, two-dimensional, equilateral, triangular islands with a fairly narrow size distribution and a well defined thickness are observed. Island nucleation occurs both at step edges and on the terraces. Upon coalescence at coverages beyond one monolayer, the surface is covered by a flat and pseudomorphic oxide film with a (1×1) surface unit cell. [Copyright &y& Elsevier]