At such high temperatures, one can observe redistribution of impurities depthwise, formation of defects on the surface, and so on. However, in the case of silicon carbide, annealing of defects requires temperatures up to 1800–2000☌. The ion implantation method allows one to achieve impurity concentration to be close to the maximal solubility. Tails reduce the breakdown voltage, and traps associated with nitrogen (which are formed at high diffusion temperatures) increase the switching time of the diodes. Differences in diffusion coefficients lead to formation of the so-called “tails” in the impurity distribution depthwise, which significantly reduces quality of the p-n junctions fabricated by means of thermal diffusion. Moreover, solubility and diffusion coefficient of impurities in different sublattices differ greatly.įor example, in the silicon sublattice, the boron solubility (∼6–9 × 10 19 cm −3) is almost an order of magnitude higher than that in the carbon sublattice (1–10 × 10 18 cm −3). Impurities move both through carbon and silicon sublattices of the crystal. Diffusion of these impurities in the silicon carbide is based on rather complex mechanism taking place at temperatures above 2000☌. Impurities of boron and aluminum are used to form p-regions in structures based on 4 H-SiC by means of ion implantation or thermal diffusion. In this regard, there is a significant interest drawn by researchers and technologists to this material. Based on silicon carbide, power electronics elements, nuclear radiation detectors, and UV LEDs for special applications are made. IntroductionĪmong wide-gap semiconductor materials (GaP, ZnS, ZnSe, ZnTe, CdS, and SiC), silicon carbide is a unique material due to high thermal conductivity and mechanical, chemical, and radiation hardness. It was shown that the use of sources of impurity atoms created by using boron and aluminum chlorides allows one to reduce the concentration of vacancy defects. The level of absorption in the samples was used to estimate concentration of defects. In the spectral dependences of optical absorption at room temperature, bands associated with transitions from impurity levels, as well as absorption bands associated with defects of the vacancy nature, were observed. Diffusion of impurities was performed from aluminum-silicate and boron-silicate films (sources) fabricated by various methods. The technique uses a scanning laser beam to create electron–hole pairs in a semiconductor sample.Optical absorption of p-n-4 H-SiC structures doped with boron and aluminum by low-temperature diffusion was studied for the first time. Optical beam induced current - (OBIC) is a semiconductor analysis technique performed using laser signal injection. Alternate names sometimes used are optically stimulated luminescence… … Wikipedia It is useful to geologists and archaeologists who want to know when such an event occurred. Optical dating - is a method of determining how long ago minerals were last exposed to daylight. Optical tomography - Intervention MeSH D041622 Optical tomography is a form of computed tomography that creates a digital volumetric model of an object by reconstructing images made from light transmitted and scattered through an … Wikipedia Because light is an electromagnetic wave, similar phenomena occur in X rays, microwaves, radio waves. Optics usually describes the behavior of visible, ultraviolet, and infrared light used in imaging. Optical imaging - is an imaging technique. In heterodyne detection, a signal of interest at some frequency is non linearly mixed with a reference local oscillator (LO) that is set at a close by frequency. Optical heterodyne detection - is an important special case of heterodyne detection. Optical tweezers - (originally called single beam gradient force trap ) are scientific instruments that use a highly focused laser beam to provide an attractive or repulsive force (typically on the order of piconewtons), depending on the refractive index mismatch… … Wikipedia absorption optique, f … Radioelektronikos terminų žodynasĪbsorption cell - noun : a transparent container in which liquids are placed for the study of their optical absorption … Useful english dictionary Optical properties of carbon nanotubes - Contents 1 Terminology 2 Electronic structure of carbon nanotube 3 Van Hove singularities … WikipediaĪbsorption optique - optinė sugertis statusas T sritis radioelektronika atitikmenys: angl. Lichtabsorptionskoeffizient, m Lichtabsorptionskonstante, f rus. light absorption coefficient optical absorption constant vok. Optical absorption constant - šviesos sugerties koeficientas statusas T sritis fizika atitikmenys: angl. absorption optique, f … Radioelektronikos terminų žodynas Optical absorption - optinė sugertis statusas T sritis radioelektronika atitikmenys: angl.