Rectifiers semiconductor devices

Use High-temperature bodies, cermets, alloys, rectifiers, semiconductor devices. 

The history of semiconductor devices can be traced back to tire paper of Braun, published in 1874, describing rectifying behavior of a contact [1], However, for many years semiconductors were considered too difficult a subject and tire science of semiconductors began only during World War IT... 

NoU It is possible that at some loealioiis there is no a.e. source available, such as (or battery-operated lifts iirul motor vehicles,. Such applications may also call for a variable d.e. source. When it is so. it can be achieved with the use of a chopper circuit which uses the conventional semiconductor devices. The devices are switched at high repetitive frequencies to obtain the required variation in the output voltage as with the use of a phase-controlled lliyristor rectifier, A typical chopper circuit is shown in Ingure 6.2, i. using diodes and a controlled unidirectional semieonduetor switch, which can be a thyristor or tin IGBT. 

Nonstoichiometric oxide phases are of great importance in semiconductor devices, in heterogeneous catalysis and in understanding photoelectric, thermoelectric, magnetic and diffusional properties of solids. They have been used in thermistors, photoelectric cells, rectifiers, transistors, phosphors, luminescent materials and computer components (ferrites, etc.). They are cmcially implicated in reactions at electrode surfaces, the performance of batteries, the tarnishing and corrosion of metals, and many other reactions of significance in catalysis. ... 

Silicide formation has been reviewedand the interaction between thin metal films and Si substrates is of interest for the use of silicides as ohmic or rectifying contacts and as interconnects in Si semiconductor device technology. Information about metal-silicon (M-Si) phase diagrams is also available . 

When a transformer-rectifier operates at full current but below its rated output voltage, its power efficiency declines. This is because the losses remain virtually unchanged while the power output falls proportionately with voltage. If the same transformer-rectifier operates at full voltage but below its rated output current, the reverse is true. The power efficiency increases because the resistive losses decrease with the square of the current while the power output falls only linearly. The efficiency improvement is not as great as might be expected from this statement, because the no-load (iron) losses of a transformer do not reduce at all and the rectifier losses are only partly resistive. The latter reflects the fact that semiconductor devices have fixed voltage drops in addition to their resistive losses. 

The term rectifier arose in fhe 1940s for macroscopic semiconductor devices, which have a junction between two semiconductors having relatively free charge carriers with opposite signs. The older term, diode, was defined in the early 1900s for vacuum tubes that transmitted electrical currents in a vacuum with different efficiencies in the forward and reverse directions because of the geometrical shapes of the electrodes. 

A metal-semiconductor junction is an integral part of any semiconductor device, and hence, it is crucial to understand their nature. Properties of a semiconductor-metal junction often closely resembles that of a semiconductor-electrolyte junction, as both can be rectifying in nature. However, the space-charge region in the metal is usually neglected because the high density of states causes very little penetration of the electric field beyond the surface. 

A Bhalla, TP Chow. Bipolar power device performance dependence on materials, lifetime, and device ratings. International Symposium on Power Semiconductor Devices and ICs, 1994, p 287. M Bhatnagar, H Nakanishi, S Bothra, PM McLarty, BJ Baliga. Edge terminations for SiC high voltage Schottky rectifiers. International Symposium on Power Semiconductor Devices and ICs, 1993, p 89. 

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