LYCOS RETRIEVER 
Semiconductors
built 232 days ago
Semiconductors are materials that are neither conductors nor insulators. Rather they have resistivities intermediate between those of conductors like copper and insulators like plastic. The semiconductors used in practical devices are made mainly from silicon or germanium that has been "doped" by the addition of a small amount of an impurity. If the impurity adds some extra electrons that are free to move in the material, it is called n-type semiconductor because of the negative charge of the electrons. If the impurity removes some electrons, it creates "holes" in the crystal lattice: unoccupied places that could accommodate an electron. The holes are positively charged because an electron is missing from them.
Source:
Semiconductors are special materials (frequently silicon-based) that conduct differently under different conditions. This is, of course, only a partial definition, but it is certainly an important part. Semiconductors can be used to control the flow of electricity in a circuit, they can be used to amplify a signal, or they can be used to switch current flow on or off. In fact, this is only a small subset of the things that semiconductors can do. This book will explain what semiconductors are, and how they are used.
Source:
Semiconductors with predictable, reliable electronic properties are necessary for mass production. The level of chemical purity needed is extremely high because the presence of impurities even in very small proportions can have large effects on the properties of the material. A high degree of crystalline perfection is ... required, since faults in crystal structure (such as dislocations, twins, and stacking faults) interfere with the semiconducting properties of the material. Crystalline faults are a major cause of defective semiconductor devices. The larger the crystal, the more difficult it is to achieve the necessary perfection. Current mass production processes use crystal ingots between four and twelve inches (300 mm) in diameter which are grown as cylinders and sliced into wafers.
Source:
Inova Semiconductors, an ISO9001 certified company, works closely with system partners and leading worldwide semiconductor packaging manufacturers (foundries) to ensure the highest performance and quality for their customers. Inova Semiconductors is represented in all major regions of the world through distribution partners and a direct sales and marketing force.
Source:
MORE ABOUT
Semiconductors