The determination by X-ray diffraction of the elastic strain tensors and the corresponding stress tensors in patterned lines of tungsten has been performed to investigate the effect of various passivation. For unpassivated lines, the stresses are biaxial and decrease with decreasing line width. Passivation over patterned lines results in triaxial tensile stress. The stress along the line is not changed by the passivation. The stress across the line decreases as the line width decreases. The third component of stress, perpendicular to the surface, which appears with the passivation, increases with decreasing line width. High compressive intrinsic stress in the passivation does not result in high tensile stress in the metal line.

In situ experiments using synchrotron X-ray topography and high-voltage electron microscopy (HVEM) have been carried out in order to study dislocation transmission through (122), ∑=9 coincidence tilt boundaries in elemental semiconductors. Both techniques proved that this boundary greatly hinders dislocation motion. However, dislocations with the common ½[011] Burgers vector, parallel to the tilt axis, can be transmitted from one crystal to the other. X-ray experiments brought several other types of transmission to light, but these were not confirmed by HVEM observations. This suggests that they were not true transmission reactions but resulted from the activation of pre-existing nearby dislocation sources by internal stresses arising from dislocation pile-ups against the grain boundary, in the opposite crystal.

2014 L'utilisation du silicium polycristallin pour les cellules solaires pose le problème de l'effet des joints de grains sur les propriétés électroniques de ce type de matériau : diffusion des impuretés aux joints de grains, propriétés électriques du joint en relation avec l'existence de liaisons pendantes et d'impuretés.Des bicristaux de silicium où l'interface entre deux grains voisins peut être parfaitement définie ont été préparés pour étudier les propriétés des joints de grains.Les échantillons ont été obtenus par la méthode de Czochralski avec du silicium du type p et du type n.Abstract.2014 Utilization of polycrystalline silicon for solar cell applications poses the problem of the effects of grain boundaries on the electronic properties of this type of material: preferential impurity diffusion at the boundary, electrical properties of the boundary in relation to the existence of dangling bonds and impurities.Silicon bicrystals, where the interface between two adjacent grains can be well defined, have been grown to study the properties of the grain boundaries.Such specimens have been realized by the Czochralski growth technique with p-type and n-type silicon.

Dislocation transmission through a (122), ∑ = 9 boundary in Ge or Si is first studied from the crystallographic point of view. Grain-boundary structure alterations induced by transmission reactions suggested by experimental observations are investigated. The Burgers vectors of extrinsic grain-boundary dislocations and their associated steps are determined. A possible transmission process, which accounts for lattice dislocation dissociation, i.e. transmission of the leading Shockley partial without constriction, is discussed. The strain transmission is also examined using calculations of internal shear stresses exerted by dislocation pileups, in one crystal, at the interface, on all the second crystal's slip systems. Interpretation of the observed transmission reactions is attempted by combining the crystallographic and the dynamic criteria.

The atomic structure of grain boundaries in germanium and silicon has been recently studied using high energy electron-diffraction, high resolution imaging and the α-fringe method on tilt 〈011〉 GBs. The results are examined in view of the data already obtained on clean semiconductor surfaces. It is shown that GBs tend to favour commensurate structures. Complete reconstruction occurs, sometimes forming a superstructure, and restoring the tetracoordination. New structural units typical of each GB geometry are then formed. The importance of defects in this periodic arrangement is emphasized particularly to explain their electrical activity.

A contribution to the study of the [001] symmetrical tilt boundary structure in diamond-structure materials is presented, based on an examination of a germanium ∊= 5 (130) bicrystal very close to the coincidence orientation relationship. From an α fringe contrast analysis and an electron diffraction study, the relative position of the adjacent crystals and the interface are deduced. A structural model of the ∊ = 5 (130) boundary is suggested and discussed on the basis of Hornstra's early work.

The structure of the [011] σ = 9 and σ = 11 symmetrical tilt grain boundaries in germanium, very close to the exact coincidence orientation, has been studied using the α-fringe and electron diffraction techniques. Diffraction patterns from the grain boundary at various inclinations were recorded, those at normal incidence examined in detail, and fine matrix and double-diffracted spots identified. The boundary zones are dilated, and from the results of both techniques we can conclude that there is no rigid body translation parallel to the grain boundary. The σ = 9 periodicity is that of the coincidence site lattice, while that of the σ = 11 bicrystal is double. In both cases there is a glide-reflection plane parallel to the grain boundary which leads to the existence of favourable, symmetrically alternated atomic arrangements. Five-ring and seven-ring units and “boat-shaped” six-ring units are combined in geometrical models without dangling bonds.

An in-situ tensile test of Al-6wt.%Mg alloy has been conducted to explore the relations between slip transmission with fracture behavior. Detailed in-situ electron backscatter diffraction characterization and analysis of 1400 grain boundaries (GBs) were carried out at five different strain states. Three slip transmission parameters, Schmid factor m, Luster-Morris parameter m′, and residual Burgers vector Δb, were analyzed to characterize the dislocation-GBs interactions. Both intergranular and intragranular fracture was observed in the tensile test. The intergranular fractures tend to occur at slip-blocked GBs due to local strain concentration. The intragranular fracture traces coincide with grains having GBs where slip transmission traces were observed. The revealed correlations of slip transmission/blockage with fracture can be applied to failure analysis and simulation of polycrystalline materials.

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. ETUDE PAR MICROSCOPIE ELECTRONIQUE CONVENTIONNELLE EN TRANSMISSION DES DISLOCATIONS INTERGRANULAIRES INTRINSEQUES J. Bacmann

Utilization of polycrystalline silicon for solar cell applications poses the problem of the effects of grain boundaries on the electronic properties of this type of material: preferential impurity diffusion at the boundary, electrical properties of the boundary in relation to the existence of dangling bonds and impurities. Silicon bicrystals, where the interface between two adjacent grains can be well defined, have been grown to study the properties of the grain boundaries. Such specimens have been realized by the Czochralsky growth technique with p-type silicon (boron, 20 ß cm).

The present study shows that in germanium, in a Σ= 25 coincidence boundary, apart from the ground state three different kinds of interfacial domain can exist.

High angle tilt boundaries in germanium bicrystals have been studied using transmission electron microscopy.