Abstract

The main focus of this report was to get an over view of the silicon carbide, which occurs in a variety of polymorphic crystal forms, that are usually designated ß-SiC for the cubic form and a-SiC to hexagonal and rhombohedral varieties. In this report, introduction of the topic on hand is given with details of discovery of the material. It was discovered 1885, at that time Achelson succeeded in growing a SiC layer and gave this material the name of SiC. After going through with the discovery the characteristics of the material, its structure, application and uses are also discussed in detail. This substance is known as the only binary compound semiconductor. Silicon carbide (t mp 2830 ° C), is chemically resistant, with hardness second only to diamond and boron nitride.

Silicon Carbide

Introduction

Silicon carbide (carborundum), SiC. Pure silicon carbide of stoichiometric composition - colorless crystals with diamond glitter. SiC may have a variety of colors, which range from white, gray, yellow, green and black. The color of the material depends on the raw materials and technology of crystal and is defined as the type and amount of impurities, and the degree of deviation from the stoichiometric composition. Silicon carbide crystallizes in two modifications: at temperatures below 2000 ° C - in the cubic sphalerite-type (b-SiC), and at higher temperatures - in the hexagonal (a-SiC). For high-temperature, hexagonal silicon carbide characterized phenomenon politipizma: found more than 50 polytypic modifications of a-SiC (Ley, pp. 124-235).

Discovery of Silicon Carbide

SiC is not a newcomer to the scene of semiconductors. Indeed, the first report on this material dates from 1824. The properties of this material were then unknown. In 1885, Achelson succeeded in growing a SiC layer and gave it the name of SiC. In 1907, the first LED on SiC substrate was designed. In 1955, Lely proposed a new concept to grow layers of high quality SiC. 1978 was a year major in the SiC with the sublimation growth technique which is actually a method derived from that of Lely. SiC can withstand large electric fields or the doping level maximum for a given breakdown voltage is proportional to the square of the field So the breakdown doping will be multiplied by 100 compared to the classical and if the low R channel may lead to strong currents with low loss power as R channel is inversely proportional to the cube of the electric field breakdown. In addition, thanks to its wide band gap, SiC can operate at high temperatures (> 600 ° C) while the components in B are limited to 150 ° C. Silicon carbide has been the most widely used material for structural ceramic applications.

Features such as thermal expansion relatively low, the high radio power-weight, high thermal conductivity, hardness, resistance to abrasion and corrosion, and most importantly, maintaining the elastic resistance at temperatures up to 1650 ° C, have led a wide range of applications. It is also possible to produce large quantities of pure powders of silicon carbide and ...