Crystal diode

A semiconductor diode - an electrical device with a p-n-junction, having a nonlinear current-voltage characteristic. The apparatus used for current rectification, a part of the bridges of various kinds. Semiconductor diode circuit is indicated on the dark (less transparent) triangle with a vertex and perpendicular feature at the cathode (n-region).

Basic Terms and Definitions

By the semiconductor diode is accepted to a number of classes, rightly identified as a separate family. This varicap, zener diodes, LEDs, and so on. General becomes presence of a single p-n-junction. Tube rectifier diodes are also called. In this context and applicable semiconductor epithet to note the presence of p-n-junction.

Diodes are prized for pronounced rectifying properties. The current flows through the p-n-transition in one direction, which solves a large variety of technical problems. Mass applied rectifying properties of semiconductors and integrated circuits, including crystals. Although the processors for the most part on the substrate are formed the transistors included viewed as two semiconductor diode forward. Redundancy is justified by the unification of the technological cycle.

Rectifying properties of semiconductor diodes are visible on the example of the copper sulfide. This is not difficult to read in the historical information below. In addition, the semiconductor diodes are based on any natural mineral nonmetals IV, V and VI groups various oxides, alloys of the organic dyes (LEDs used for the specified class substances).

The history of the development of semiconductor technology

The first "crystal" diodes

Contrary to common belief the rectifying properties of the metal-semiconductor (Schottky diode) have long been known. Broadly semiconductor technology began to develop by leaps and bounds after World War II. The causes of the incident:

1. In wartime, the majority of countries led research into new technologies. For example, I was born and was immediately kept secret transistor. As well as the first operational amplifier to be used to drive the flak anti-aircraft defense system. This invention could be used to see the light, the first work in the said area were carried out at the beginning of 30-ies of XX century.
2. Approximately 10 years before the outbreak of the Second World War, most countries appeared in the course of future events. Not surprisingly, that was kept secret favorites information.
3. If we take into consideration the fascist Germany, its government for reasons of long-cherished enmity refuses to communicate with the other European powers. The occasion was the outcome of the First World War.

Thus, the semiconductor technology began to develop in the conditions of the newly created United Nations, to ensure peace in the land, and received its charter. Rectifying properties of semiconductors are visible German scientist Karl Ferdinand Braun, Get on with a pair of Marconi Nobel Prize for the development of the wireless telegraph (radio) in 1909. Unfortunately, there is no possibility to find a job translating «Ueber die Stromleitung durch Schwefelmetalle», published in the journal Annalen der Physik und Chemie in 1874 under the number 153.

Two years earlier, in March 1872, Karl received his PhD for his work in the area of ​​the vibrating string. Then remains at the Berlin University. Scientific director of the work, Georg Quincke, was assigned to Würzburg, and both follow where the focus is on the conductivity of materials. Published a report on the passage of current through the molten salts and the rectifying properties of the gas layers with different conductivity. Initially intrigued by lead salts, Carl Braun reached finally to copper sulfide.

November 23, 1874 in light of the work function for a discussion of artificial and natural samples of material from the point of view of electrical conductivity. Selected showed the difference in the resistance depending on the direction is 30%. It is found that in one direction of conductivity of the sample depends on the current strength of the current measured by the galvanometer. So we discover and nonlinear material properties, now exhibited by semiconductor diodes. At the same time the effect was dependent on the method of application of metallic electrodes, indicating anisotropy detected qualities.

At that time it was considered inexplicable happens, the observed result contradicted the known scientific facts. Today it is known that a metal-semiconductor has rectifying properties on a par with the p-n-junction. The difference is that the first voltage drop less. Accordingly, semiconductor Schottky diodes are used as rectifiers in the output stages of power supplies. In said time Werner Siemens discovered unilateral conductivity selenium crystals. But Brown added another range of materials, among other things - psilomelane (manganese ore), creating the first antennal (dot) diode.

A first detector for radio

Brown ideas found practical application Jagadis Chandra Bos, collected first detector for a radio frequency of a millimeter wave galena (lead sulphide) and to receive a US patent number 755,840, filed September 30, 1901 and approved in March 1904. Bengali scientist reported on the invention in 1899 by the Royal Society of England. Already in December 1901 the unit used to decrypt the transatlantic telegraph transmission Marconi.

Soon, new detectors:

• Patent number 836,531, filed August 20, 1906 Greenleaf Pickard, notable for the fact that for the first time here refers to the silicon crystal (with English. - silicone).
• Henry Dunwoody March 23, 1906 for the purposes of rectifying the current use of silicon carbide (carborundum). Material synthesized first and only later found on the ruins of a fallen meteorite.

Some time crystal detector was used and even gave direction LEDs in electronics, but with the invention of vacuum tubes semiconductors have gone on the back burner. And so it happened to the post-war years. Since the beginning of the 50's and the entry into use transistors, and most importantly - germanium semiconductor technology develops by leaps and bounds today.

explanation found

Only in 1928, Arnold Sommerfeld and young Felix Bloch (Bloch electrons) explained the opening of Brown from the standpoint of quantum mechanics. In the first approximation, the new direction of science is not difficult to learn from the notes in 1931 On the quantum mechanics of electrons in crystal lattices authored Gronich and Penny from Groningen University. Russian-speaking readers easier to get acquainted with the one-dimensional model of the motion of electrons in a periodic field, which for the first time clearly illustrates the nature of the occurrence of the energy bands in the crystal.

It is shown that the energy distribution function is continuous. Present the permitted area, separated by forbidden. Today, on the theory known to every student of the school physics course, but a pioneering role entirely given to Shockley, that's not entirely true. In fact, a complete theory, which agrees well with practice, summed up under the semiconductors Hans Bethe in 1942 (a few years later the famous colleagues).

The rapid development of semiconductor technology

In the postwar years, the benefits of manufacture of semiconductor technology were not yet clear. At the beginning of 50's production is occupied by two American companies:

1. Texas Instruments (1951 - dedicated spin-offs from United geophysical service) with 1950 produces semiconductor transistors, and today has a leading role in the production of electronic components. Notorious Jack Kilby, the inventor of integrated circuits, working in said company. At the time of the mid-50 Texas Instruments won first place in terms of turnover in the production of semiconductor technology.
2. The now defunct company Transitron, founded in 1952 by Leo and David Bakalar, by 1955 on a par with Texas Instruments produces more than a third of all semiconductor devices in a matter of years, he rose to tops. Parent for Texas Instruments company existed since 1930, worked in war on the government and enjoyed wide popularity. At 1961 Transitron means a turnover of 40 million. dollars. And it is up to the first oil crisis! David was listed as president until 1984, the company ceased to exist a couple of years.

Transitron decline began in the '60s, when they wrongly abandoned new directions. We are talking about integrated circuits. Prospects gained silicon, though primarily due to fame germany. For more information about the causes of the situation can be found in topic about bipolar transistors.

Add in semiconductor technology require such a high degree of silicon purity, that at the time of the mid XX century, the production came out extremely expensive. At the same time germanium devices show smaller limit temperature (85 degrees Celsius) and when overheated easily fail. It is easy to understand why Transitron, refused to invest in innovation, since the mid-60s began to suffer serious losses.

The recent strength of the company were taken away from developing its own microprocessor, which did not have commercial success. By the way, germanium, according to some estimates, will once again be a very promising and the semiconductor element. For example, based on it created and rectifiers. And not only to radio, but also the industrial network 50 Hz 220 V, which makes them promising as replacement of bulky relays.

Shockley Semiconductor diodes

In 1956, William Shockley founded in Palo Alto (California), his own company at Sauf Antonio Road 391. This is the first enterprise engaged in semiconductors, in the place where now is located the famous Silicon Valley. The main product was 4-layer diode, called among professionals transistor diode or a Shockley diode.

According to the authors equipment had come to replace conventional relays in the communications industry. But because of the complexity of the realization of the idea it was not to the teeth technology of the time. Readers have already guessed that we are talking about the thyristors with a regenerative response. Thus, the diode can be called and said wafer. Or rather - Shockley diode.

It consists of 4 alternating conductivity type semiconductor layers. Full-called n-type cathode, an anode and an opposite, as a conventional diode. Shockley diode is based on avalanche breakdown, the transitions are locked again after lowering the voltage, and the system returns to its original state.

new time

If in the early 70's for the production of semiconductor materials clearly in the lead of the USA, at the dawn of the 80's, Japan began to build momentum. Southeast Asia and Europe were the last who joined the race. Today, four mentioned region about equally divided volumes of production, and, of course, a blanket pulled over China in the first decade of the XXI century, doubled the volume of the issue. According to some projections Beijing 2020 will take half of the world production.