Three-dimensional defect

Three Dimensional Defect Analysis Using Stereoradioscopy Based on Camera Modelling. 

Monitoring surface structures, especially during thin-film epitaxial growth can distinguish two- and three-dimensional defects... 

Point defects can, for the sake of cataloging, be considered to be zero dimensional. Extended defects with higher dimensionality can also be described. One-dimensional defects extend along a line, two-dimensional defects extend along a plane, and three-dimensional defects occupy a volume. In this chapter these extended defects are introduced. 

An extension of the kinetic theory on cases when a mechanical pressure interacts with kinetic processes inside solid volume and on interfaces has wide application interests. The elastic deformations in solid are presented from influence of external forces and from presence of internal defects of crystal structure point defects (vacancy, intersite atoms, complexes of atoms, etc.), extended defects (dislocations and inner interfaces in polycrystals), and three-dimensional defects (heterophases crystals, polycrystals). 

Pores or cavities (three-dimensional defects) represent microcracks, holes or bubbles of gaseous phase included within the crystal, and other impurity phases. 

Inclusions Inclusions are three-dimensional defects consisting of soluble particles of foreign material in the metal. Voids, a three-dimensional defect, are empty or gas-filled spaces within the metal. Metal oxides, sulfides, and silicates are common inclusions. For example, manganese sulfide in stainless steel provides a favorable site for pitting corrosion. 

Amorphous Defects are Three-dimensional Defects, Typical for Macromolecules... 

Figure 5.88 is an illustration of two-dimensional defects in the form of surfaces and grain boundaries. They either terminate a crystal or separate it from the three-dimensional defects. In polymer crystals, these surfaces and grain boundaries are rarely clean terminations of single-crystalline domains, as one would expect from the unit cell descriptions in Sect. 5.1. The surfaces may contain folds or chain ends and may be traversed by tie molecules to other crystals and cilia and loose loops that enter the amorphous areas, as is illustrated in Figs. 5.87 and 2.98. The properties of a polycrystalline sample are largely determined by the cohesion achieved across such surfaces and the mechanical properties of the interlamellar material, the amorphous defects. 

A suitable classification of crystalline defects can be achieved by first considering the so-called point defects and then proceeding to higher-dimensional defects. Point defects are atomic defects whose effect is limited only to their immediate surroundings. Examples are vacancies in the regular lattice, or interstitial atoms. Dislocations are classified as linear or one-dimensional defects. Grain boundaries, phase boundaries, stacking faults, and surfaces are two-dimensional defects. Finally, inclusions or precipitates in the crystal matrix can be classified as three-dimensional defects. 

Exploit the full capabilities of defect engineering to avoid one-, two-, and three-dimensional defects of critical sizes, and spacings that tri er certain corrosion modes and their spreading. This is especially necessary in classes of alloys where heterogeneity is unavoidable, as in the case of precipitation age-hardened alloys. 

Besides this molecular incorporation of impurities into the lattice either by a finite solubility or kinetic incorporation, impurities can also be incorporated into the growing crystal in three-dimensional defects, as liquid inclusions (Figure 7.1 right). 

Body defect or three-dimensional defects. It means that there are larger defects in three-dimensional orientation, such as impurities, settlings and hollow spaces included in solids. This defect is not a part of the same phase with the fiducial crystal, but a heterogeneous defect. 

Defect theories of melting have been discussed in the context of crystal melting for some time [13]. In the usual three-dimensional defect melting theory, the free energy Fdef for production of a defect out of a perfect crystal is calculated as a function of temperature. As the temperature increases, Fdef is found to decrease smoothly from a positive to a negative value, passing... 

We distingiiish between point defects (zero dimensional defects) — these are atomic and electronic imperfections line (one-dimensional) defects — these are essentially dislocations plane (two-dimensional) defects — i.e. surfaces and basically internal interfaces and pores or inclusions as three-dimensional defects. We will not discuss other variants of higher-dimensional disorder, which can be very compleot, particularly in multiphase systems. Since we concentrate on the equilibrium state in this chapter, we are primarily interested in point defects and surfaces. Point defects exist at equilibrium on accoimt of entropy surfaces are a necessary consequence of the requirement that the amoimt of substance is finite. Defects of other types are necessarily nonequilibrium phenomena", which will be demonstrated in Section 5.4. Nonetheless, the higher-dimensional defects will, as metastable structure elements, be important for us later (see Sections 5.4, 5.8). 

As with all other classes of materials, one of the primary keys (if not THE key) to engineering a semiconductor is control of defects in its structure. Defects can be divided into classes according to their dimensionality. Thus, zero (jwint), one (line), two (plane) and three (volume) dimensional defects occur in semiconductors and each is significant is considered in turn, although two and three-dimensional defects will be lumped together as they behave similarly. Furthermore, the behaviors of two and three-dimensional defects can be considered to be extensions of zero and one-dimensional behaviors. Therefore, we will spend more time on the latter two. In this chapter we wUl consider only defects in crystalline materials. Amorphous semiconductors, the ultimate in defective materials, are considered in the following chapter. 

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