E.I. Givargizov - Böcker

This 18th volume of the series includes invited papers from the Seventh All-Union Conference on the Growth of Crystals and the Symposium on Molecular-Beam Epitaxy that were held in Moscow in November, 1988. In choosing papers, the Program Committee of the conference gave priority to studies in rapidly emerging areas of the growth and preparation of crystalS and crystalline films. The qualifications of the authors were also consid­ ered. This ensured that the material was of a high standard and that the problems discussed covered a wide range. These are the same criteria that, we hope, are typical of the volumes of this series. The articles of the present volume are divided into four sections: I. Processes on the growth surface. II. Molecular-beam epitaxy. III. Growth of crystals and films from solutions and fluxes. N. Growth of crystals from the melt. Following tradition, the series opens with three theoretical articles. These examine problems applicable to various crystallization media: instability of the crystallization front (for a more general case than before and for a comparatively complicated system, a solution), adsorption and migration of atoms and molecules (the analysis is made on a quantum-chemical level), and the kinetics of step and dislocation growth in the presence of surface anisotropy as well as impurity adsorption (several earlier known methods are summarized). The next two articles are experimental and methodical.

Volume 19 includes articles on growth of crystals from the vapor, from the melt, and from fluxes, as well as a section on actual structure of crystals and films relative to growth conditions.

In keeping with tradition, this collection covers three principal crystallization methods: from the vapor, solution, and the melt. The five articles of the first part are concerned with heterostructure formation. O. P. Pchelyakov and L. V. Sokolov report on controlled growth of nanostructures in the Si-Ge system using an array of modern analytical tools to follow the process in situ. A different method for growing quantum-sized Si-Ge structures is used by Mil'vidskii et al., chemical deposition of hydrides from the vapor. Stresses and misfit dislocations in the resulting heterostructures are thoroughly investigated. The theoretical work of E. M. Trukhanov examines the formation mechanism of long-range stresses that produce r -shaped cracks during the growth of thick Ge-Si films. The reasons for the manifestation of macro defects connected with the generation of twins in HgCdTe films are unraveled by Yu. G. Sidorov et al. The conditions under which films with a low defect density grow are found. The preparation of highly oxidized amorphous Nb films and the structures formed during the crystallization of these films are reported by A. A. Sokol et al.Growth from solutions is the subject of the four articles in the second part.

This title presents a survey, with detailed analysis, of the scientific and technological approaches, and results obtained, by leading Russian crystal growth specialists from the late 1990s onwards. The volume contains 16 reviewed chapters on various aspects of crystal and crystalline film growth from various phases (vapour, solution, liquid and solid). Both fundamental aspects, e.g. growth kinetics and mechanisms, and applied aspects, for example, preparation of technically important materials in single-crystalline forms, are covered. A large portion of the volume is devoted to film growth, including film growth from eutectic melt, from amorphous solid state, kinetics of lateral epitaxy and film growth on specially structured substrates. An important chapter in this section covers heteroepitaxy of non-isovalent A3B5 semiconductor compounds, which have important applications in the field of photonics. The volume also includes a detailed analysis of the structural aspects of a broad range of laser crystals, information that is invaluable for successfully growing perfect, laser-effective, single crystals

Present-day scienceand technology have become increasingly based on studies and applications of thin films. This is especiallytrue of solid-state physics, semiconduc­ tor electronics, integrated optics, computer science, and the like. In these fields, it is necessary to use filmswith an ordered structure, especiallysingle-crystallinefilms, because physical phenomena and effects in such films are most reproducible. Also, active parts of semiconductor and other devices and circuits are created, as a rule, in single-crystal bodies. To date, single-crystallinefilms have been mainly epitaxial (or heteroepitaxial); i.e., they have been grown on a single-crystalline substrate, and principal trends, e.g., in the evolution of integrated circuits (lCs), have been based on continuing reduction in feature size and increase in the number of components per chip. However, as the size decreases into the submicrometer range, technological and physical limitations in integrated electronics become more and more severe. It is generally believed that a feature size of about 0.1um will have a crucial character. In other words, the present two-dimensional ICs are anticipated to reach their limit of minimization in the near future, and it is realized that further increase of packing density and/or functions might depend on three-dimensional integration. To solve the problem, techniques for preparation of single-crystalline films on arbitrary (including amorphous) substrates are essential.

The present volume of this series, following the tradition of the previous volumes, covers three major lines of research on crystallization: growth from vapor and epitaxy, growth from solution, and growth from melt. As in the previous volumes, preference is given to papers that provide original results and reviews of results obtained by the authors and those from published sources, although some of the papers are either purely original or purely of review character. The first section deals with crystal growth from vapor and epitaxy and contains three papers. One of them, on artificial epitaxy, discusses and reviews published results from the last three years in this rapidly developing area. The results are used in outlining mechanisms for oriented film growth on amorphous substrates. Another paper in this section deals with classical epitaxy, namely oriented growth on single-crystal substrates, where some important conclusions are drawn from the growth of gallium nitride films on sapphire, which concern the orientation relationships in that pair of substances. The last paper in the section deals with film growth under ion bombardment (the corresponding techniques in film crystallization have already advanced from theory to practical applications).

Present-day scienceand technology have become increasingly based on studies and applications of thin films. This is especiallytrue of solid-state physics, semiconduc­ tor electronics, integrated optics, computer science, and the like. In these fields, it is necessary to use filmswith an ordered structure, especiallysingle-crystallinefilms, because physical phenomena and effects in such films are most reproducible. Also, active parts of semiconductor and other devices and circuits are created, as a rule, in single-crystal bodies. To date, single-crystallinefilms have been mainly epitaxial (or heteroepitaxial); i.e., they have been grown on a single-crystalline substrate, and principal trends, e.g., in the evolution of integrated circuits (lCs), have been based on continuing reduction in feature size and increase in the number of components per chip. However, as the size decreases into the submicrometer range, technological and physical limitations in integrated electronics become more and more severe. It is generally believed that a feature size of about 0.1um will have a crucial character. In other words, the present two-dimensional ICs are anticipated to reach their limit of minimization in the near future, and it is realized that further increase of packing density and/or functions might depend on three-dimensional integration. To solve the problem, techniques for preparation of single-crystalline films on arbitrary (including amorphous) substrates are essential.

Anisotropy, i.e., the dependence of structure and properties on direction in space, is the most striking characteristic of crystals. Anisotropy is a result of the discrete nature of the crystal lattice, and it is the characteristic which distinguishes the crystalline state from another solid state of matter, the amorphous. The anisotropy of the structure and properties of crystals (this can be called their 'internal anisotropy') is also reflected in their external structure, i.e., morphology. The reflection is, however, non-linear: properties such as mechanical hardness ... do not change strongly (typically several tens of percents, depending on direction) while the morphology ... : the linear sizes in different directions of individual crystals often differ by several multiples or even several orders of magnitude, depending on the symmetry of the crystalline lattice and/or of the crystal prehistory. The enhanced anisotropy of morphology is, as a rule, a result of growth kinetics of different crystalline faces; it reflects a non-linear character of the kinetic laws of growth. This book is devoted to high morphological anisotropy. No strict classification of highly-anisotropic crystals exists. However some typical forms, or habits, can be singled out: first, whiskers (or needles, or fibers) as quasi-one-dimensional crystals, and second, platelets as quasi-two-dimensional crystals.