Изучение процессов формирования массивов капель золота на подложках кремния методом высокотемпературного отжига

In this study, the peculiarities of the transformations of gold films deposited on the Si wafer surfaces as a result of high temperature anneals are investigated experimentally depending on the conditions of wafer surface preparation and the annealing regimes. The morphology and the distribution functions of the crystallites of gold films as well as the gold droplets formed as a result of anneals are studied as functions of annealing temperature, type of annealing (rapid thermal or rapid furnace annealing), and the state of the surface of Si wafers. The results obtained can be used for the controlled preparation of the arrays of catalytic gold droplets for subsequent growth of Si wire-like crystals.В роботі вивчено особливості трансформації золотих плівок, нанесених на поверхню кремнієвих пластин, в результаті високотемпературного відпалу в залежності від умов підготовки поверхні пластин та режимів відпалу. Морфологія і розподіл кристалітів плівок золота, а також масивів крапель золота, сформованих в результаті відпалу, досліджені як функції температури і типу відпалу (швидкий термічний або швидкий відпал в печі) та стану поверхні пластин Si. Отримані результати можуть бути використані для контролю виготовлення масивів каталітичних крапель золота для подальшого вирощування нитковидних кристалів Si.В работе изучены особенности трансформации золотых пленок, нанесенных на поверхность кремниевых пластин, в результате высокотемпературного отжига в зависимости от условий подготовки поверхности пластин и режимов отжига. Морфология и распределение кристаллитов пленок золота, а также массивов капель золота, сформированных в результате отжига, исследованы как функции температуры и типа отжига (быстрый термический или быстрый отжиг в печи) и состояния поверхности пластин Si. Полученные результаты могут быть использованы для контроля изготовления массивов каталитических капель золота для последующего выращивания нитевидных кристаллов Si

The role of multicomponent surface diffusion in growth and doping of silicon nanowires

The metal-catalyzed chemical vapor deposition on silicon substrates remains one of the most promising technologies for growing the silicon nanowires up to now. The process involves a wide variety of elementary events (adsorption, desorption, and multicomponent atomic transport with strongly different local mobility, etc.) that take place on the same surface sites and proceed on isolated nano-scaled part of the surface belonging to different individual catalyst particle. In this work, the competition for unoccupied sites during atomic transport under growth doping and percolation-related phenomena on confined parts of surface was treated by the Monte-Carlo simulations. Atomistic simulations were compared with numerical kinetic modeling. Arising nonlinear effects that finally lead to specific modes of the nanoobject growth, shaping, and doping were analyzed. By combining different kinds of simulations and experimental results, the proposed strategy provides a better control at atomic scale of nanowire growth. Both atomistic and kinetic considerations supplementing each other reveal the importance of surface transport and the role of surface immobile contaminations in the nanowire growth

Physico-Chemical model and computer simulations of silicon nanowire growth

A model of catalytically enhanced CVD growth of a silicon nanowire assembly on a substrate is developed, and growth process is simulated. Thermodynamic-kinetic theory is used for modeling of molecular transport in the gas phase, processes near catalyst surface and nanowire side of variable curvature, bulk diffusion of silicon adatoms through catalyst – body, and 2D nucleation. The simulation of atomic transport across surfaces is based on a long-wave approach of lattice gas approximation. To determine a character of atomic transport in TiSi₂-catalyst that is of great importance for application in Si-based technology, a density functional theory is used. The main result of modeling is that it is found a relationship between growth conditions (an initial radius of catalyst particles, their density, substrate temperature, content, pressure of gas, as well as properties of materials used) and, on the other hand, a growth rate, shape, composition, and type of atomic structure (amorphous or crystalline) of the nanowires grown. Besides, available experimental data published previously are discussed, and a qualitative agreement between theory and various experiments is obtained. This agreement gives rise to use the found relationship for controlling the nanowire growth

Finite size suppression of the weak field magnetoresistance of lightly phosphorous-doped silicon

We report magnetoresistance measurements of lightly phosphorous doped silicon in samples that are fabricated from silicon-on-insulator wafers and so confined in one dimension. All three principal magnetic field orientations were studied at 50 and 270 K for thicknesses between 1.5−530 μm, and as thin as 150 nm at 270 K. The weak field magnetoresistance was suppressed in the orientations with the field in the sample plane when the sample is thinner than ∼1 μm at 270 K (∼10 μm at 50 K). This suppression occurred for samples that are much thicker than the carrier mean free path and the Debye screening length, and the relevant lengthscale is instead the energy relaxation length

On the role of modern doctrines on human rights (International legal examination)

© BEIESP. The modern doctrines on human rights, which are proposed to be considered in the context of their implementation in international legal practice, are the subject of theoretical and legal analysis in the paper. It is noted that human rights have come a long way in their formation, design and subsequent genesis, and they have finally formed by the end of the last century, and it seems that now all the necessary conditions have been created for their philosophical, legal, axiological analysis and relevant rational consideration of human rights. The advantages of international law in the field of human rights are listed; namely, it is noted that international human rights standards are universal in nature and are binding based on which states are obliged to ensure a minimum standard of those rights and freedoms that are enshrined in international acts, There are listed in the paper advantages of international legal regulation regarding human rights and freedoms, such as the supranational, mandatory and imperative nature of international acts; guarantees of protection and the possibility of restoring violated rights and freedoms of citizens; a man-centred approach in resolving disputes and conflicts arising in international practice. The role of international bodies such as the International Criminal Court, the International Tribunal for the Law of the Sea, the Court of the European Union, the European Court of Human Rights, the International Tribunals for Rwanda and the Former Yugoslavia, and the Special Court for Sierra Leone, is emphasized. Particular attention is paid to the principle of presumption of innocence, which has fundamental and quintessential characteristics in the field of human rights

On the role of modern doctrines on human rights (International legal examination)

© BEIESP. The modern doctrines on human rights, which are proposed to be considered in the context of their implementation in international legal practice, are the subject of theoretical and legal analysis in the paper. It is noted that human rights have come a long way in their formation, design and subsequent genesis, and they have finally formed by the end of the last century, and it seems that now all the necessary conditions have been created for their philosophical, legal, axiological analysis and relevant rational consideration of human rights. The advantages of international law in the field of human rights are listed; namely, it is noted that international human rights standards are universal in nature and are binding based on which states are obliged to ensure a minimum standard of those rights and freedoms that are enshrined in international acts, There are listed in the paper advantages of international legal regulation regarding human rights and freedoms, such as the supranational, mandatory and imperative nature of international acts; guarantees of protection and the possibility of restoring violated rights and freedoms of citizens; a man-centred approach in resolving disputes and conflicts arising in international practice. The role of international bodies such as the International Criminal Court, the International Tribunal for the Law of the Sea, the Court of the European Union, the European Court of Human Rights, the International Tribunals for Rwanda and the Former Yugoslavia, and the Special Court for Sierra Leone, is emphasized. Particular attention is paid to the principle of presumption of innocence, which has fundamental and quintessential characteristics in the field of human rights