Semiconductor devices are electronic components that exploit the electronic properties of semiconductor materials, principally silicon, germanium, and gallium arsenide. Semiconductor devices have replaced thermionic devices (vacuum tubes) in most applications. They use electronic conduction in the solid state as opposed to the gaseous state or thermionic emission in a high vacuum. An electronic component is a basic electronic building block packaged in a discrete form with two or more connecting leads or metallic pads. ... // Electronics is the study of electron mechanics. ... A semiconductor is a solid whose electrical conductivity can be controlled over a wide range, either permanently or dynamically. ... It has been suggested that Silicons ranking be merged into this article or section. ... General Name, Symbol, Number germanium, Ge, 32 Chemical series metalloids Group, Period, Block 14, 4, p Appearance grayish white Atomic mass 72. ... This article is about the chemical compound. ... In electronics, a vacuum tube or (outside North America) thermionic valve or just valve, is a device generally used to amplify, switch or otherwise modify, a signal by controlling the movement of electrons in an evacuated space. ... e- redirects here. ... Electrical conduction is the movement of electrically charged particles through a transmission medium (electrical conductor). ... In electronics, solid state circuits are those that do not contain vacuum tubes. ... -1...

Semiconductor devices are manufactured both as single discrete devices and as integrated circuits (ICs), which consist of a number—from a few to millions—of devices manufactured and interconnected on a single semiconductor substrate. Integrated circuit showing memory blocks, logic and input/output pads around the periphery Microchips with a transparent window showing the integrated circuit inside. ...

Semiconductor device fundamentals

The main reason semiconductor materials are so useful is that the behaviour of a semiconductor can be easily manipulated by the addition of impurities, known as doping. Semiconductor conductivity can be controlled by introduction of an electric field, by exposure to light, and even pressure and heat; thus, semiconductors can make excellent sensors. Current conduction in a semiconductor occurs via mobile or "free" electrons and holes (collectively known as charge carriers). Doping a semiconductor such as silicon with a small amount of impurity atoms, such as phosphorus or boron, greatly increases the number of free electrons or holes within the semiconductor. When a doped semiconductor contains excess holes it is called "p-type", and when it contains excess free electrons it is known as "n-type". The semiconductor material used in devices is doped under highly controlled conditions in a fabrication facility, or fab, to precisely control the location and concentration of p- and n-type dopants. The junctions which form where n-type and p-type semiconductors join together are called p-n junctions. In semiconductor production, doping refers to the process of intentionally introducing impurities into an intrinsic semiconductor in order to change its electrical properties. ... Electrical conductivity or specific conductivity is a measure of a materials ability to conduct an electric current. ... It has been suggested that this article or section be merged with Electromagnetic radiation. ... A semiconductor is a solid whose electrical conductivity can be controlled over a wide range, either permanently or dynamically. ... Properties The electron (also called negatron, commonly represented as e−) is a subatomic particle. ... For the following two reasons the electron hole was introduced into calculations: If an electron is excited into higher state it leaves a hole in its old state. ... Charge carrier denotes in physics a free (mobile, unbound) particle carrying an electric charge. ... It has been suggested that Silicons ranking be merged into this article or section. ... General Name, Symbol, Number phosphorus, P, 15 Chemical series nonmetals Group, Period, Block 15, 3, p Appearance waxy white/ red/ black/ colorless Standard atomic weight 30. ... General Name, Symbol, Number boron, B, 5 Chemical series metalloids Group, Period, Block 13, 2, p Appearance black/brown Atomic mass 10. ... It has been suggested that this article or section be merged into Fabrication plant. ... A p-n junction is formed by combining N-type and P-type semiconductors together in very close contact. ...

Diode

The p-n junction diode is a device made from a p-n junction. At the junction of a p-type and an n-type semiconductor there forms a region called the depletion zone which blocks current conduction from the n-type region to the p-type region, but allows current to conduct from the p-type region to the n-type region. Thus when the device is forward biased, with the p-side at higher electric potential, the diode conducts current easily; but the current is very small when the diode is reverse biased. Types of diodes closeup, showing germanium crystal In electronics, a diode is a component that restricts the direction of movement of charge carriers. ... In semiconductor physics, the Depletion Zone or Depletion layer is a nonconductive region within a conductive, doped semiconductor material where the charge carriers have been swept away. ... Electric potential is the potential energy per unit of charge associated with a static (time-invariant) electric field, also called the electrostatic potential, typically measured in volts. ...

Exposing a semiconductor to light can generate electron–hole pairs, which increases the number of free carriers and its conductivity. Diodes optimized to take advantage of this phenomenon are known as photodiodes. Compound semiconductor diodes can also be used to generate light, as in light-emitting diodes and laser diodes. It has been suggested that this article or section be merged with Electromagnetic radiation. ... In the solid state physics of semiconductors, carrier generation and recombination are processes by which mobile electrons and electron holes are created and eliminated. ... A photodiode Photodiode closeup A photodiode is a semiconductor diode that functions as a photodetector. ... A Compound semiconductor is composed of elements from two or more different groups of the chemical periodic table, e. ... Led is also the past tense of the verb to lead Blue, green and red LEDs. ... A packaged laser diode with penny for scale. ...

Transistor

Two MOS transistors with common gate (metallic layers and dielectric removed for clarity).

Bipolar junction transistors are formed from two p-n junctions, in either n-p-n or p-n-p configuration. The middle, or base, region between the junctions is typically very narrow. The other regions, and their associated terminals, are known as the emitter and the collector. A small current injected through the junction between the base and the emitter changes the properties of the base-collector junction so that it can conduct current even though it is reverse biased. This creates a much larger current between the collector and emitter, controlled by the base-emitter current. Assorted discrete transistors A transistor is a semiconductor device, commonly used as an amplifier. ... Image File history File links Transistor_3d. ... Image File history File links Transistor_3d. ... The schematic symbols for pnp_ and npn_type BJTs. ...

Another type of transistor, the field effect transistor operates on the principle that semiconductor conductivity can be increased or decreased by the presence of an electric field. An electric field can increase the number of free electrons and holes in a semiconductor, thereby changing its conductivity. The field may be applied by a reverse-biased p-n junction, forming a junction field effect transistor, or JFET; or by an electrode isolated from the bulk material by an oxide layer, forming a metal-oxide-semiconductor field effect transistor, or MOSFET. Large power N-channel field effect transistor The field-effect transistor (FET) is a transistor that relies on an electric field to control the shape and hence the conductivity of a channel in a semiconductor material. ... It has been suggested that optical field be merged into this article or section. ... Electric current flow from source to drain in a p-channel JFET is restricted when a voltage is applied to the gate. ... The metal-oxide-semiconductor field-effect transistor (MOSFET, MOS-FET, or MOS FET) is by far the most common field-effect transistor in both digital and analog circuits. ...

Cross-section through a MOS transistor (metallic layers and dielectric removed for clarity), foreground.

The MOSFET is the most used semiconductor device today. The gate electrode is charged to produce an electric field that controls the conductivity of a "channel" between two terminals, called the source and drain. Depending on the type of carrier in the channel, the device may be an n-channel (for electrons) or a p-channel (for holes) MOSFET. Although the MOSFET is named in part for its "metal" gate, in modern devices polysilicon is typically used instead. Image File history File links Transistor_3d_xsection. ... Image File history File links Transistor_3d_xsection. ... It has been suggested that optical field be merged into this article or section. ... Electrical conductivity or specific conductivity is a measure of a materials ability to conduct an electric current. ... Polycrystalline silicon or polysilicon or poly-Si is a material consisting of multiple small silicon crystals, and has long been used as the conducting gate material in MOSFET and CMOS processing technologies. ...

Semiconductor device materials

Main article: Semiconductor materials

By far, silicon (Si) is the most widely used material in semiconductor devices. Its combination of low raw material cost, relatively simple processing, and a useful temperature range make it currently the best compromise among the various competing materials. Silicon used in semiconductor device manufacturing is currently fabricated into boules that are large enough in diameter to allow the production of 300 mm (12 in.) wafers. Semiconductor materials are insulators at absolute zero temperature that conduct electricity in a limited way at room temperature (see also Semiconductor). ... It has been suggested that Silicons ranking be merged into this article or section. ... Silicon boule for the production of wafers. ... A millimetre (American spelling: millimeter), symbol mm is an SI unit of length that is equal to one thousandth of a metre. ... An inch (plural: inches; symbol or abbreviation: in or, sometimes, ″ - a double prime) is the name of a unit of length in a number of different systems, including English units, Imperial units, and United States customary units. ... An etched silicon wafer In microelectronics, a wafer is a thin slice of semiconducting material, such as a silicon crystal, upon which microcircuits are constructed by doping (for example, diffusion or ion implantation), etching, and deposition of various materials. ...

Germanium (Ge) was a widely used early semiconductor material but its thermal sensitivity makes it less useful than silicon. Today, germanium is often alloyed with silicon for use in very-high-speed SiGe devices; IBM is a major producer of such devices. General Name, Symbol, Number germanium, Ge, 32 Chemical series metalloids Group, Period, Block 14, 4, p Appearance grayish white Atomic mass 72. ... International Business Machines Corporation (known as IBM or Big Blue; NYSE: IBM) is a multinational computer technology corporation headquartered in Armonk, New York, USA. The company is one of the few information technology companies with a continuous history dating back to the 19th century. ...

Gallium arsenide (GaAs) is also widely used in high-speed devices but so far, it has been difficult to form large-diameter boules of this material, limiting the wafer diameter to sizes significantly smaller than silicon wafers thus making mass production of GaAs devices significantly more expensive than silicon. This article is about the chemical compound. ...

Other less common materials are also in use or under investigation.

Silicon carbide (SiC) has found some application as the raw material for blue light-emitting diodes (LEDs) and is being investigated for use in semiconductor devices that could withstand very high operating temperatures and environments with the presence of significant levels of ionizing radiation. IMPATT diodes have also been fabricated from SiC. Silicon carbide (SiC) is a ceramic compound of silicon and carbon and occurs in nature as the extremely rare mineral moissanite. ... Led is also the past tense of the verb to lead Blue, green and red LEDs. ... Radiation hazard symbol. ... An IMPATT diode (IMPact ionization Avalanche Transit-Time) is a form of high power diode used in high-frequency electronics and microwave devices. ...

Various indium compounds (indium arsenide, indium antimonide, and indium phosphide) are also being used in LEDs and solid state laser diodes. Selenium sulfide is being studied in the manufacture of photovoltaic solar cells. General Name, Symbol, Number indium, In, 49 Chemical series poor metals Group, Period, Block 13, 5, p Appearance silvery lustrous gray Atomic mass 114. ... General Name, Symbol, Number antimony, Sb, 51 Chemical series metalloids Group, Period, Block 15, 5, p Appearance silvery lustrous grey Atomic mass 121. ... General Name, Symbol, Number phosphorus, P, 15 Chemical series nonmetals Group, Period, Block 15, 3, p Appearance waxy white/ red/ black/ colorless Standard atomic weight 30. ... A packaged laser diode with penny for scale. ... Se redirects here. ... Formally, sulfide is the dianion, S2−, which exists in strongly alkaline aqueous solutions formed from H2S or alkali metal salts such as Li2S, Na2S, and K2S. Sulfide is exceptionally basic and, with a pKa > 14, it does not exist in appreciable concentrations even in highly alkaline water. ... A solar cell, a form of photovoltaic cell, is a device that uses the photoelectric effect to generate electricity from light, thus generating solar power (energy). ... A solar cell, made from a monocrystalline silicon wafer A solar cell or photovoltaic cell is a device that converts light energy into electrical energy. ...

List of common semiconductor devices

Two-terminal devices:

• Avalanche diode (avalanche breakdown diode)
• DIAC
• Diode (rectifier diode)
• Gunn diode
• IMPATT diode
• Laser diode
• Light-emitting diode (LED)
• Photocell
• PIN diode
• Schottky diode
• Solar cell
• Tunnel diode
• VCSEL
• VECSEL
• Zener diode

Three-terminal devices: An avalanche diode is a diode (usually made from silicon, but can be made from another semiconductor) that is designed to break down and conduct at a specified reverse bias voltage. ... DIAC For other uses, see DIAC (disambiguation). ... Types of diodes closeup, showing germanium crystal In electronics, a diode is a component that restricts the direction of movement of charge carriers. ... A rough approximation of the VI curve for a Gunn diode, showing the negative differential resistance region A Gunn diode, also known as a transferred electron device (TED) is a form of diode used in high-frequency electronics. ... An IMPATT diode (IMPact ionization Avalanche Transit-Time) is a form of high power diode used in high-frequency electronics and microwave devices. ... A packaged laser diode with penny for scale. ... Led is also the past tense of the verb to lead Blue, green and red LEDs. ... A photoresistor is an electronic component whose resistance decreases with increasing incident light intensity. ... A PIN diode (Positive-Intrinsic-Negative diode) is a photodiode with a large, neutrally doped intrinsic region sandwiched between p-doped and n-doped semiconducting regions. ... The Schottky diode (named after German physicist Walter H. Schottky) is a semiconductor diode with a low forward voltage drop and a very fast switching action. ... A solar cell, made from a monocrystalline silicon wafer A solar cell or photovoltaic cell is a device that converts light energy into electrical energy. ... Tunnel diode schematic symbol A tunnel diode or Esaki diode is a type of semiconductor diode which is capable of very fast operation, well into the microwave region GHz, by utilizing quantum mechanical effects. ... Diagram of a simple VCSEL structure. ... A Vertical-External-Cavity Surface-Emitting-Laser (VECSEL) is a small, tunable semiconductor laser similar to a VCSEL. VECSELs are used primarily as near infrared devices in laser cooling and spectroscopy. ... Zener diode schematic symbol A Zener diode is a type of diode that permits current to flow in the forward direction like a normal diode, but also in the reverse direction if the voltage is larger than the rated breakdown voltage or Zener voltage. A conventional solid-state diode will...

• Bipolar transistor
• Darlington transistor
• Field effect transistor
• IGBT (Insulated Gate Bipolar Transistor)
• SCR (Silicon Controlled Rectifier)
• Thyristor
• Triac
• Unijunction transistor

Four-terminal devices: The schematic symbols for pnp_ and npn_type BJTs. ... It has been suggested that this article or section be merged with darlington pair. ... Large power N-channel field effect transistor The field-effect transistor (FET) is a transistor that relies on an electric field to control the shape and hence the conductivity of a channel in a semiconductor material. ... A power IGBT The Insulated (or sometimes called Isolated) Gate Bipolar Transistor combines the simple gate drive characteristics of the MOSFET with the high current and low saturation voltage capability of bipolar transistors by combining an isolated gate FET for the control input, and a bipolar power transistor as a... A Silicon Controlled Rectifier (or semiconductor controlled rectifier) is a 4-layer solid state device that controls current flow. ... Circuit symbol for a thyristor The thyristor is a solid-state semiconductor device with four layers of alternating N and P-type material. ... Triac Schematic Symbol A TRIAC, or TRIode for Alternating Current is an electronic component approximately equivalent to two silicon-controlled rectifiers (SCRs/thyristors) joined in inverse parallel (paralleled but with the polarity reversed) and with their gates connected together. ... A Unijunction transistor (UJT) is an electronic semiconductor device. ...

• Hall effect sensor (magnetic field sensor)

Multi-terminal devices: The magnetic piston (1) in this pneumatic cylinder will cause the Hall effect sensors (2 and 3) mounted on its outer wall to activate when it is fully retracted or extended. ...

• Charge-coupled device (CCD)
• Microprocessor
• Random Access Memory (RAM)
• Read-only memory (ROM)

A specially developed CCD used for ultraviolet imaging in a wire bonded package. ... A microprocessor is a programmable digital electronic component that incorporates the functions of a central processing unit (CPU) on a single semiconducting integrated circuit (IC). ... Random access memory (usually known by its acronym, RAM) is a type of data storage used in computers. ... Read-only memory (often referred to as its acronym ROM) is a class of storage media used in computers and other electronic devices. ...

Semiconductor device applications

All transistor types can be used as the building blocks of logic gates, which are fundamental in the design of digital circuits. In digital circuits like microprocessors, transistors act as on-off switches; in the MOSFET, for instance, the voltage applied to the gate determines whether the switch is on or off. A logic gate performs a logical operation on one or more logic inputs and produces a single logic output. ... Digital circuits are electric circuits based on a number of discrete voltage levels. ... A microprocessor is a programmable digital electronic component that incorporates the functions of a central processing unit (CPU) on a single semiconducting integrated circuit (IC). ... International safety symbol Caution, risk of electric shock (ISO 3864), colloquially known as high voltage symbol. ... Electrical switches. ...

Transistors used for analog circuits do not act as on-off switches; rather, they respond to a continuous range of inputs with a continuous range of outputs. Common analog circuits include amplifiers and oscillators. It has been suggested that this article or section be merged with Analog electronics. ... Generally, an amplifier is any device that uses a small amount of energy to control a larger amount of energy. ... Oscillation is the periodic variation, typically in time, of some measure as seen, for example, in a swinging pendulum. ...

Circuits that interface or translate between digital circuits and analog circuits are known as mixed-signal circuits. A mixed-signal integrated circuits combines analog and digital circuitry. ...

Power semiconductor devices are discrete devices or integrated circuits intended for high current or high voltage applications. Power integrated circuits combine IC technology with power semiconductor technology, these are sometimes referred to as "smart" power devices. Several companies specialize in manufacturing power semiconductors. Power semiconductor devices are semiconductor devices used as switches or rectifiers in power electronic circuits (switch mode power supplies for example). ...

Component identifiers

The type designators of semiconductor devices are often manufacturer specific. Nevertheless, there have been attempts at creating standards for type codes, and a subset of devices follow those. For discrete devices, for example, there are three standards: JEDEC JESD370B in USA, Pro Electron in Europe and JIS in Japan. A discrete device is an electronic component with just one circuit element. ... JEDEC stands for Joint Electron Device Engineering Council and is the semiconductor engineering standardization body of the Electronic Industries Alliance (EIA), a trade association that represents all areas of the electronics industry. ... Pro Electron is the European type designation and registration system for active components (such as semiconductors, liquid crystal displays, sensor devices, electronic tubes and cathode ray tubes, ...). Pro Electron was set up in 1966 in Brussels, Belgium. ... This article is 150 kilobytes or more in size. ... Japanese Industrial Standards (JIS) specifies the standards used for industrial activities in Japan. ...

History of semiconductor device development

1900s

Semiconductors had been used in the electronics field for some time before the invention of the transistor. Around the turn of the 20th century they were quite common as detectors in radios, used in a device called a "cat's whisker". These detectors were somewhat troublesome, however, requiring the operator to move a small tungsten filament (the whisker) around the surface of a galena (lead sulfide) or carborundum (silicon carbide) crystal until it suddenly started working. Then, over a period of a few hours or days, the cat's whisker would slowly stop working and the process would have to be repeated. At the time their operation was completely mysterious. After the introduction of the more reliable and amplified vacuum tube based radios, the cat's whisker systems quickly disappeared. The "cat's whisker" is a primitive example of a special type of diode still popular today, called a Schottky diode. A Cats Whisker is the tiny wire that connects to the detector in a crystal radio. ... Galena is a lead ore. ... Silicon carbide (SiC) or moissanite is a ceramic compound of silicon and carbon. ... In electronics, a vacuum tube or (outside North America) thermionic valve or just valve, is a device generally used to amplify, switch or otherwise modify, a signal by controlling the movement of electrons in an evacuated space. ... The Schottky diode (named after German physicist Walter H. Schottky) is a semiconductor diode with a low forward voltage drop and a very fast switching action. ...

World War II

During World War II, radar research quickly pushed radar receivers to operate at ever higher frequencies and the traditional tube based radio receivers no longer worked well. The introduction of the cavity magnetron from Britain to the United States in 1940 during the Tizard Mission resulted in a pressing need for a practical high-frequency amplifier. This long range Radar antenna, known as ALTAIR, is used to detect and track space objects in conjunction with ABM testing at the Ronald Reagan Test Site on the Kwajalein atoll[1]. Radar is a system that uses radio waves to determine and map the location, direction, and/or speed... Sine waves of various frequencies; the lower waves have higher frequencies than those above. ... A cavity magnetron is a high-powered vacuum tube that generates coherent microwaves. ... In the late Sepember 1940 during the Battle of Britain in the Second World War, a delegation arrived from the UK in the United States on a mission instigated by Henry Tizard, known as the Tizard Mission. ...

On a whim, Russell Ohl of Bell Laboratories decided to try a cat's whisker. By this point they had not been in use for a number of years, and no one at the labs had one. After hunting one down at a used radio store in Manhattan, he found that it worked much better than tube-based systems. Russell Ohl is generally recognized for patenting the modern solar cell (US2402662, Light sensitive device). Ohl was a notable semiconductor researcher prior to the invention of the transistor. ... Bell Telephone Laboratories or Bell Labs was originally the research and development arm of the United States Bell System, and was the premier corporate facility of its type, developing a range of revolutionary technologies from telephone switches to specialized coverings for telephone cables, to the transistor. ... For other uses, see Manhattan (disambiguation). ...

Ohl investigated why the cat's whisker functioned so well. He spent most of 1939 trying to grow more pure versions of the crystals. He soon found that with higher quality crystals their finicky behaviour went away, but so did their ability to operate as a radio detector. One day he found one of his purest crystals nevertheless worked well, and interestingly, it had a clearly visible crack near the middle. However as he moved about the room trying to test it, the detector would mysteriously work, and then stop again. After some study he found that the behaviour was controlled by the light in the room–more light caused more conductance in the crystal. He invited several other people to see this crystal, and Walter Brattain immediately realized there was some sort of junction at the crack. Walter Houser Brattain (February 10, 1902 – October 13, 1987) was a physicist who, along with John Bardeen, invented the transistor. ...

Further research cleared up the remaining mystery. The crystal had cracked because either side contained very slightly different amounts of the impurities Ohl could not remove–about 0.2%. One side of the crystal had impurities that added extra electrons (the carriers of electrical current) and made it a "conductor". The other had impurities that wanted to bind to these electrons, making it (what he called) an "insulator". Because the two parts of the crystal were in contact with each other, the electrons could be pushed out of the conductive side which had extra electrons (soon to be known as the emitter) and replaced by new ones being provided (from a battery, for instance) where they would flow into the insulating portion and be collected by the whisker filament (named the collector). However, when the voltage was reversed the electrons being pushed into the collector would quickly fill up the "holes" (the electron-needy impurities), and conduction would stop almost instantly. This junction of the two crystals (or parts of one crystal) created a solid-state diode, and the concept soon became known as semiconduction. The mechanism of action when the diode is off has to do with the separation of charge carriers around the junction. This is called a "depletion region". Charge carrier denotes in physics a free (mobile, unbound) particle carrying an electric charge. ... In semiconductor physics, the depletion region, also called depletion layer or depletion zone, is an insulating region within a conductive, doped semiconductor material where the charge carriers have been swept away through recombination. ...

Development of the diode

Armed with the knowledge of how these new diodes worked, a vigorous effort began in order to learn how to build them on demand. Teams at Purdue University, Bell Labs, MIT, and the University of Chicago all joined forces to build better crystals. Within a year germanium production had been perfected to the point where military-grade diodes were being used in most radar sets. Purdue redirects here. ... Bell Laboratories (also known as Bell Labs and formerly known as AT&T Bell Laboratories and Bell Telephone Laboratories) was the main research and development arm of the United States Bell System. ... The Massachusetts Institute of Technology (MIT) is a private, coeducational research university located in Cambridge, Massachusetts. ... The University of Chicago is a private university located principally in the Hyde Park neighborhood of Chicago. ...

Development of the transistor

After the war, William Shockley decided to attempt the building of a triode-like semiconductor device. He secured funding and lab space, and went to work on the problem with Brattain and John Bardeen. William Bradford Shockley (February 13, 1910 – August 12, 1989) was a British-born American physicist and inventor. ... Simplified diagram of a triode. ... John Bardeen (May 23, 1908 – January 30, 1991) was an American physicist and electrical engineer. ...

The key to the development of the transistor was the further understanding of the process of the electron mobility in a semiconductor. It was realized that if there was some way to control the flow of the electrons from the emitter to the collector of this newly discovered diode, one could build an amplifier. For instance, if you placed contacts on either side of a single type of crystal the current would not flow through it. However if a third contact could then "inject" electrons or holes into the material, the current would flow. This does not adequately cite its references or sources. ...

Actually doing this appeared to be very difficult. If the crystal were of any reasonable size, the number of electrons (or holes) required to be injected would have to be very large -– making it less than useful as an amplifier because it would require a large injection current to start with. That said, the whole idea of the crystal diode was that the crystal itself could provide the electrons over a very small distance, the depletion region. The key appeared to be to place the input and output contacts very close together on the surface of the crystal on either side of this region. Generally, an amplifier is any device that uses a small amount of energy to control a larger amount of energy. ...

Brattain started working on building such a device, and tantalizing hints of amplification continued to appear as the team worked on the problem. Sometimes the system would work but then stop working unexpectedly. In one instance a non-working system started working when placed in water. Ohl and Brattain eventually developed a new branch of quantum mechanics known as surface physics to account for the behaviour. The electrons in any one piece of the crystal would migrate about due to nearby charges. Electrons in the emitters, or the "holes" in the collectors, would cluster at the surface of the crystal where they could find their opposite charge "floating around" in the air (or water). Yet they could be pushed away from the surface with the application of a small amount of charge from any other location on the crystal. Instead of needing a large supply of injected electrons, a very small number in the right place on the crystal would accomplish the same thing. Fig. ... Surface chemistry is the study of chemical phenomena that occur at the interface of two phases, usually between a gas and a solid or between a liquid and a solid. ...

Their understanding solved the problem of needing a very small control area to some degree. Instead of needing two separate semiconductors connected by a common, but tiny, region, a single larger surface would serve. The emitter and collector leads would both be placed very close together on the top, with the control lead placed on the base of the crystal. When current was applied to the "base" lead, the electrons or holes would be pushed out, across the block of semiconductor, and collect on the far surface. As long as the emitter and collector were very close together, this should allow enough electrons or holes between them to allow conduction to start.

The first transistor

A stylized replica of the first transistor

The Bell team made many attempts to build such a system with various tools, but generally failed. Setups where the contacts were close enough were invariably as fragile as the original cat's whisker detectors had been, and would work briefly, if at all. Eventually they had a practical breakthrough. A piece of gold foil was glued to the edge of a plastic wedge, and then the foil was sliced with a razor at the tip of the triangle. The result was two very closely spaced contacts of gold. When the plastic was pushed down onto the surface of a crystal and voltage applied to the other side (on the base of the crystal), current started to flow from one contact to the other as the base voltage pushed the electrons away from the base towards the other side near the contacts. The point-contact transistor had been invented. Image File history File links Replica-of-first-transistor. ... Image File history File links Replica-of-first-transistor. ...

While the device was constructed a week earlier, Brattain's notes describe the first demonstration to higher-ups at Bell Labs on the afternoon of 23 December 1947, often given as the birthdate of the transistor. The "PNP point-contact germanium transistor" operated as a speech amplifier with a power gain of 18 in that trial. Known generally as a point-contact transistor today, John Bardeen, Walter Houser Brattain, and William Bradford Shockley were awarded the Nobel Prize in physics for their work in 1956. December 23 is the 357th day of the year in the Gregorian calendar (358th in leap years). ... 1947 (MCMXLVII) was a common year starting on Wednesday (the link is to a full 1947 calendar). ... A point-contact transistor was the first type of transistor ever constructed. ... John Bardeen (May 23, 1908 – January 30, 1991) was an American physicist and electrical engineer. ... Walter Houser Brattain (February 10, 1902 – October 13, 1987) was a physicist at Bell Labs who, along with John Bardeen and William Shockley invented the transistor. ... William Bradford Shockley (February 13, 1910 – August 12, 1989) was a physicist and co-inventor of the transistor with John Bardeen and Walter Houser Brattain, for which he was awarded the Nobel Prize in physics. ... The Nobel Prizes (Swedish: ) are awards in physics, chemistry, literature, peace, physiology or medicine. ...

Origin of the term "transistor"

Bell Telephone Laboratories needed a generic name for their new invention: "Semiconductor Triode", "Solid Triode", "Surface States Triode" [sic], "Crystal Triode" and "Iotatron" were all considered, but "transistor", coined by John R. Pierce, won an internal ballot. The rationale for the name is described in the following extract from the company's Technical Memoranda (May 28, 1948) [26] calling for votes: John Robinson Pierce (March 27, 1910 - April 2, 2002), was an American engineer and author. ... May 28 is the 148th day of the year in the Gregorian calendar (149th in leap years). ... 1948 (MCMXLVIII) was a leap year starting on Thursday (the link is to a full 1948 calendar). ...

Transistor. This is an abbreviated combination of the words "transconductance" or "transfer", and "varistor". The device logically belongs in the varistor family, and has the transconductance or transfer impedance of a device having gain, so that this combination is descriptive.

Improvements in transistor design

Shockley was upset about the device being credited to Brattain and Bardeen, who he felt had built it "behind his back" to take the glory. Matters became worse when Bell Labs lawyers found that some of Shockley's own writings on the transistor were close enough to those of an earlier 1925 patent by Julius Edgar Lilienfeld that they thought it best that his name be left off the patent application. Julius Edgar Lilienfeld (1881 – 1963) was born in Germany and emigrated to the USA in 1927. ...

Shockley was incensed, and decided to demonstrate who was the real brains of the operation. Only a few months later he invented an entirely new type of transistor with a layer or 'sandwich' structure. This new form was considerably more robust than the fragile point-contact system, and would go on to be used for the vast majority of all transistors into the 1960s. It would evolve into the bipolar junction transistor. A bipolar junction transistor (BJT) is a type of transistor. ...

With the fragility problems solved, a remaining problem was purity. Making germanium of the required purity was proving to be a serious problem, and limited the number of transistors that actually worked from a given batch of material. Germanium's sensitivity to temperature also limited its usefulness. Scientists theorized that silicon would be easier to fabricate, but few bothered to investigate this possibility. Gordon K. Teal was the first to develop a working silicon transistor, and his company, the nascent Texas Instruments, profited from its technological edge. Germanium disappeared from most transistors by the late 1960s. General Name, Symbol, Number germanium, Ge, 32 Chemical series metalloids Group, Period, Block 14, 4, p Appearance grayish white Atomic mass 72. ... Gordon K. Teal (1907- Jan. ... Texas Instruments (NYSE: TXN), better known in the electronics industry (and popularly) as TI, is an American company based in Dallas, Texas, USA, renowned for developing and commercializing semiconductor and computer technology. ...

Within a few years, transistor-based products, most notably radios, were appearing on the market. A major improvement in manufacturing yield came when a chemist advised the companies fabricating semiconductors to use distilled water rather than tap water: calcium ions were the cause of the poor yields. "Zone melting", a technique using a moving band of molten material through the crystal, further increased the purity of the available crystals. Distilled water is water that has virtually all of its impurities removed through distillation (boiling the water and re-condensing the steam into a clean container, leaving contaminants behind). ... General Name, Symbol, Number calcium, Ca, 20 Chemical series alkaline earth metals Group, Period, Block 2, 4, s Appearance silvery white Atomic mass 40. ... “Multivalent” redirects here. ... Zone melting is a method of separation by melting in which a series of molten zones traverses a long ingot of impure metal or chemical. ...

See also

Electronics Portal

• Integrated circuit
• VLSI
• Category:Semiconductor device fabrication

Image File history File links Nuvola_apps_ksim. ... Integrated circuit showing memory blocks, logic and input/output pads around the periphery Microchips with a transparent window showing the integrated circuit inside. ... Very-large-scale integration (VLSI) is the process of creating integrated circuits by combining thousands of transistor-based circuits into a single chip. ...

References

• Muller, Richard S., and Theodore I. Kamins (1986). Device Electronics for Integrated Circuits. John Wiley and Sons. ISBN 0-471-88758-7.