Epitaxial growth amorphous

The oriented overgrowth of a crystalline phase on the surface of a substrate that is also crystalline is called epitaxial growth [104]. Usually it is required that the lattices of the two crystalline phases match, and it can be a rather complicated process [105]. Some new applications enlist amorphous substrates or grow new phases on a surface with a rather poor lattice match. 

In addition, there are some multilayer systems without epitaxial growth, consisting of crystal/amorphous constituents, amorphous/amorphous constituents, such as TiN/CNx... 

The primary difference in the operating conditions for growth of crystalline as compared with amorphous material is the deposition temperature. In the current design, 500 K is assumed for amorphous film deposition, while higher temperatures in the range 700-950 K are required for epitaxial growth. The low-temperature amorphous film deposition first is used to optimize the process, while the high-temperature epitaxial deposition subsequently is used as the basis for a detailed economic analysis. 

For the deposition of silicon on Si(001) and Si(l 11) surfaces, Gossmann and Feldman determined that epitaxial growth occurs for substrate temperatures maintained over 570 K and 640 K, respectively . Above the epitaxial temperature the growth is single crystal, while below this temperature the growth is amorphous. This difference in epitaxial growth temperature between the two faces was ascribed by Gossmann and Feldman to be due to the different surface reconstructions, where the (111) surface presumably... 

Organic matrices with a capactiy to act as morphological catalyst in the deposition of minerals must consequently be crystalline in nature. In the literature, colloidal or amorphous phases are frequently postulated as organic starting materials in biomineralization. Such a viewpoint, however, is not consistent with oriented epitaxial growth. 

Several strategies were appUed to produce samples for TEM and kinetic studies [8, 21], but only one route is presented here (Fig. 15.3). Noble metal nanoparticles were grown via metal evaporation on a crystalline soluble substrate (e.g., NaCl(OOl)), leading to an epitaxial growth of particles with regular shape and well-developed low-Miller index facets (Fig. 15.3). Thereafter, the metal particles were embedded in a thin (25 nm) amorphous oxide fdm, before the metal-oxide system was lifted off the substrate via flotation in water [8, 18, 20, 31]. 

Epitaxial films frequently have superior characteristics than either polycrystalline or amorphous films. The epitaxial growth concerns a large number of materials silicon, silicon-germanium alloys, III-V compounds, binary and ternary composites, metals, etc. 

When single-crystal substrates with a small lattice mismatch are used, sol-gel produces epitaxial films for a few ferroelectric systems. Although epitaxial growth of crystalline films from an amorphous layer has been observed in the amorphous silicon to silicon transformation, sol-gel epitaxy only began to emerge as a possible fabrication technique in the last few years. Hirano and Kato were the first to observe the epitaxial growth of LiNbOs on the sapphire (110) face [37]. Xu et al. [34,43] found the epitaxial growth of LiNbOs on the LiTaOs (110) face and the LiNbOa (006) face. Epitaxial KNbOs was reported... 

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