Semiconductor device
At the junction of a p-type and an n-type semiconductor, there forms a depletion region where current conduction is inhibited by the lack of mobile charge carriers.
When the device is forward biased (connected with the p-side, having a higher electric potential than the n-side), this depletion region is diminished, allowing for significant conduction.
Contrariwise, only a very small current can be achieved when the diode is reverse biased (connected with the n-side at lower electric potential than the p-side, and thus the depletion region expanded).
[4] 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.
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.)
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.
Gallium Nitride (GaN) is gaining popularity in high-power applications including power ICs, light-emitting diodes (LEDs), and RF components due to its high strength and thermal conductivity.
Silicon carbide (SiC) is also gaining popularity in power ICs and has found some application as the raw material for blue 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.
All transistor types can be used as the building blocks of logic gates, which are fundamental in the design of digital circuits.
It is a multiple-step photolithographic and physico-chemical process (with steps such as thermal oxidation, thin-film deposition, ion-implantation, etching) during which electronic circuits are gradually created on a wafer, typically made of pure single-crystal semiconducting material.
[9] FOUPs in many fabs contain an internal nitrogen atmosphere[11][12] which helps prevent copper from oxidizing on the wafers.
Additionally many machines also handle wafers in clean nitrogen or vacuum environments to reduce contamination and improve process control.
Around the turn of the 20th century they were quite common as detectors in radios, used in a device called a "cat's whisker" developed by Jagadish Chandra Bose and others.
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.
After the introduction of the more reliable and amplified vacuum tube based radios, the cat's whisker systems quickly disappeared.
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.
One side of the crystal had impurities that added extra electrons (the carriers of electric current) and made it a "conductor".
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.
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.
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).
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.
Instead of needing two separate semiconductors connected by a common, but tiny, region, a single larger surface would serve.
When current flowed through this "base" lead, the electrons or holes would be pushed out, across the block of the semiconductor, and collect on the far surface.
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.
John Bardeen, Walter Houser Brattain, and William Bradford Shockley were awarded the 1956 Nobel Prize in physics for their work.
The rationale for the name is described in the following extract from the company's Technical Memoranda (May 28, 1948) [26] calling for votes: Transistor.
Making germanium of the required purity was proving to be a serious problem and limited the yield of transistors that actually worked from a given batch of material.
Former Bell Labs scientist Gordon K. Teal was the first to develop a working silicon transistor at the nascent Texas Instruments, giving it a technological edge.
Spitzer studied the mechanism of thermally grown oxides, fabricated a high quality Si/SiO2 stack and published their results in 1960.
[39] The US Patent and Trademark Office calls the MOSFET a "groundbreaking invention that transformed life and culture around the world".
