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77-667: Although the structure of the IGBT is topologically similar to a thyristor with a "MOS" gate ( MOS-gate thyristor ), the thyristor action is completely suppressed, and only the transistor action is permitted in the entire device operation range. It is used in switching power supplies in high-power applications: variable-frequency drives (VFDs) for motor control in electric cars , trains, variable-speed refrigerators, and air conditioners, as well as lamp ballasts, arc-welding machines, photovoltaic and hybrid inverters, uninterruptible power supply systems (UPS), and induction stoves . Since it

154-502: A TRIAC , is able to work in both directions. This added capability, though, also can become a shortfall. Because the TRIAC can conduct in both directions, reactive loads can cause it to fail to turn off during the zero-voltage instants of the AC power cycle. Because of this, use of TRIACs with (for example) heavily inductive motor loads usually requires the use of a " snubber " circuit around

231-423: A bistable switch (or a latch). There are two designs, differing in what triggers the conducting state. In a three-lead thyristor, a small current on its gate lead controls the larger current of the anode-to-cathode path. In a two-lead thyristor, conduction begins when the potential difference between the anode and cathode themselves is sufficiently large (breakdown voltage). The thyristor continues conducting until

308-499: A 600 V constant-voltage source and were switched on for 25 microseconds. The entire 600 V was dropped across the device, and a large short-circuit current flowed. The devices successfully withstood this severe condition. This was the first demonstration of so-called "short-circuit-withstanding-capability" in IGBTs. Non-latch-up IGBT operation was ensured, for the first time, for the entire device operation range. In this sense,

385-551: A PNP bipolar junction transistor with the surface n-channel MOSFET . The whole structure comprises a four layered NPNP. The bipolar point-contact transistor was invented in December 1947 at the Bell Telephone Laboratories by John Bardeen and Walter Brattain under the direction of William Shockley . The junction version known as the bipolar junction transistor (BJT), invented by Shockley in 1948. Later

462-484: A combination of Greek language θύρα , meaning "door" or "valve", and transistor ) is a solid-state semiconductor device which can be thought of as being a highly robust and switchable diode , allowing the passage of current in one direction but not the other, often under control of a gate electrode, that is used in high power applications like inverters and radar generators. It usually consists of four layers of alternating P- and N-type materials. It acts as

539-504: A critical part of flashes (strobes). Thyristors can be triggered by a high rise-rate of off-state voltage. Upon increasing the off-state voltage across the anode and cathode of the thyristor, there will be a flow of charges similar to the charging current of a capacitor. The maximum rate of rise of off-state voltage or dV/dt rating of a thyristor is an important parameter since it indicates the maximum rate of rise of anode voltage that does not bring thyristor into conduction when no gate signal

616-469: A failure in the power supply from damaging downstream components. A thyristor is used in conjunction with a Zener diode attached to its gate, and if the output voltage of the supply rises above the Zener voltage, the thyristor will conduct and short-circuit the power supply output to ground (in general also tripping an upstream breaker or fuse ). This kind of protection circuit is known as a crowbar , and has

693-433: A lower value of V AK . By selecting an appropriate value of V G , the thyristor can be switched into the on state quickly. Once avalanche breakdown has occurred, the thyristor continues to conduct, irrespective of the gate voltage, until: (a) the potential V AK is removed or (b) the current through the device (anode−cathode) becomes less than the holding current specified by the manufacturer. Hence V G can be

770-464: A pnp transistor is driven by a MOSFET, was first proposed by K. Yamagami and Y. Akagiri of Mitsubishi Electric in the Japanese patent S47-21739, which was filed in 1968. In 1978 J. D. Plummer and B. Scharf patented a NPNP transistor device combining MOS and bipolar capabilities for power control and switching. The development of IGBT was characterized by the efforts to completely suppress

847-597: A practical discrete vertical IGBT device was reported by Baliga at the IEEE International Electron Devices Meeting (IEDM) that year. General Electric commercialized Baliga's IGBT device the same year. Baliga was inducted into the National Inventors Hall of Fame for the invention of the IGBT. A similar paper was also submitted by J. P. Russel et al. to IEEE Electron Device Letter in 1982. The applications for

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924-696: A relatively large amount of power and voltage with a small device, they find wide application in control of electric power, ranging from light dimmers and electric motor speed control to high-voltage direct-current power transmission. Thyristors may be used in power-switching circuits, relay-replacement circuits, inverter circuits, oscillator circuits, level-detector circuits, chopper circuits, light-dimming circuits, low-cost timer circuits, logic circuits, speed-control circuits, phase-control circuits, etc. Originally, thyristors relied only on current reversal to turn them off, making them difficult to apply for direct current; newer device types can be turned on and off through

1001-517: A significantly lower forward voltage drop compared to a conventional MOSFET in higher blocking voltage rated devices, although MOSFETS exhibit much lower forward voltage at lower current densities due to the absence of a diode Vf in the IGBT's output BJT. As the blocking voltage rating of both MOSFET and IGBT devices increases, the depth of the n- drift region must increase and the doping must decrease, resulting in roughly square relationship decrease in forward conduction versus blocking voltage capability of

1078-465: A similar electronic switching capability, where a small control voltage could switch a large current. It is from a combination of "thyratron" and " transistor " that the term "thyristor" is derived. In recent years, some manufacturers have developed thyristors using silicon carbide (SiC) as the semiconductor material. These have applications in high temperature environments, being capable of operating at temperatures up to 350 °C. The thyristor

1155-441: A switch in a single device. The IGBT is used in medium- to high-power applications like switched-mode power supplies , traction motor control and induction heating . Large IGBT modules typically consist of many devices in parallel and can have very high current-handling capabilities in the order of hundreds of amperes with blocking voltages of 6500 V . These IGBTs can control loads of hundreds of kilowatts . An IGBT features

1232-457: A thyristor can be understood in terms of a pair of tightly coupled bipolar junction transistors , arranged to cause a self-latching action. Thyristors have three states: The thyristor has three p-n junctions (serially named J 1 , J 2 , J 3 from the anode). When the anode is at a positive potential V AK with respect to the cathode with no voltage applied at the gate, junctions J 1 and J 3 are forward biased, while junction J 2

1309-429: A voltage pulse, such as the voltage output from a UJT relaxation oscillator . The gate pulses are characterized in terms of gate trigger voltage ( V GT ) and gate trigger current ( I GT ). Gate trigger current varies inversely with gate pulse width in such a way that it is evident that there is a minimum gate charge required to trigger the thyristor. In a conventional thyristor, once it has been switched on by

1386-470: Is a failure mode in bipolar power transistors. In a power transistor with a large junction area, under certain conditions of current and voltage, the current concentrates in a small spot of the base-emitter junction. This causes local heating, progressing into a short between collector and emitter. This often leads to the destruction of the transistor. Secondary breakdown can occur both with forward and reverse base drive. Except at low collector-emitter voltages,

1463-423: Is a four-layered, three-terminal semiconductor device, with each layer consisting of alternating N-type or P-type material, for example P-N-P-N. The main terminals, labelled anode and cathode, are across all four layers. The control terminal, called the gate, is attached to p-type material near the cathode. (A variant called an SCS—silicon controlled switch—brings all four layers out to terminals.) The operation of

1540-472: Is a graphical representation of the power handling capability of the device under various conditions. The SOA curve takes into account the wire bond current carrying capability, transistor junction temperature, internal power dissipation and secondary breakdown limitations. Where both current and voltage are plotted on logarithmic scales , the borders of the SOA are straight lines: SOA specifications are useful to

1617-474: Is absent, if the power is not removed and the polarities of the cathode and anode have not yet reversed, the LASCR is still in the "on" state. A light-activated TRIAC resembles a LASCR, except that it is designed for alternating currents. Thyristor manufacturers generally specify a region of safe firing defining acceptable levels of voltage and current for a given operating temperature . The boundary of this region

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1694-401: Is always greater than holding current. In the above figure I L has to come above the I H on y-axis since I L > I H . A thyristor can be switched off if the external circuit causes the anode to become negatively biased (a method known as natural, or line, commutation). In some applications this is done by switching a second thyristor to discharge a capacitor into the anode of

1771-408: Is applied. When the flow of charges due to rate of rise of off-state voltage across the anode and cathode of the thyristor becomes equal to the flow of charges as injected when the gate is energized then it leads to random and false triggering of thyristor which is undesired. This is prevented by connecting a resistor - capacitor (RC) snubber circuit between the anode and cathode in order to limit

1848-508: Is cooled with deionized water , and the entire arrangement becomes one of multiple identical modules forming a layer in a multilayer valve stack called a quadruple valve . Three such stacks are typically mounted on the floor or hung from the ceiling of the valve hall of a long-distance transmission facility. The functional drawback of a thyristor is that, like a diode, it only conducts in one direction so it cannot be safely used with AC current . A similar self-latching 5-layer device, called

1925-501: Is coupled by an optical fiber . Since no electronic boards need to be provided at the potential of the thyristor in order to trigger it, light-triggered thyristors can be an advantage in high-voltage applications such as HVDC . Light-triggered thyristors are available with in-built over-voltage (VBO) protection, which triggers the thyristor when the forward voltage across it becomes too high; they have also been made with in-built forward recovery protection , but not commercially. Despite

2002-421: Is designed to turn on and off rapidly, the IGBT can synthesize complex waveforms with pulse-width modulation and low-pass filters , thus it is also used in switching amplifiers in sound systems and industrial control systems . In switching applications modern devices feature pulse repetition rates well into the ultrasonic-range frequencies, which are at least ten times higher than audio frequencies handled by

2079-422: Is not to be confused with asymmetrical operation, as the output is unidirectional, flowing only from cathode to anode, and so is asymmetrical in nature. Thyristors can be used as the control elements for phase angle triggered controllers, also known as phase fired controllers . They can also be found in power supplies for digital circuits , where they are used as a sort of "enhanced circuit breaker " to prevent

2156-476: Is operating within its Vds, Id and Pd ratings. Some (usually expensive) MOSFETs are specified for operation in the linear region and include DC SOA diagrams, e.g. IXYS IXTK8N150L. Transistors require some time to turn off, due to effects such as minority carrier storage time and capacitance. While turning off, they may be damaged depending on how the load responds (especially with poorly snubbed inductive loads). The reverse bias safe operating area (or RBSOA )

2233-444: Is partly determined by the requirement that the maximum permissible gate power (P G ), specified for a given trigger pulse duration, is not exceeded. As well as the usual failure modes due to exceeding voltage, current or power ratings, thyristors have their own particular modes of failure, including: Thyristors are mainly used where high currents and voltages are involved, and are often used to control alternating currents , where

2310-408: Is reverse biased. As J 2 is reverse biased, no conduction takes place (Off state). Now if V AK is increased beyond the breakdown voltage V BO of the thyristor, avalanche breakdown of J 2 takes place and the thyristor starts conducting (On state). If a positive potential V G is applied at the gate terminal with respect to the cathode, the breakdown of the junction J 2 occurs at

2387-407: Is that they are not fully controllable switches. The GTO thyristor and IGCT are two devices related to the thyristor that address this problem. In high-frequency applications, thyristors are poor candidates due to long switching times arising from bipolar conduction. MOSFETs, on the other hand, have much faster switching capability because of their unipolar conduction (only majority carriers carry

Insulated-gate bipolar transistor - Misplaced Pages Continue

2464-488: Is the SOA during the brief time before turning the device into the off state—during the short time when the base current bias is reversed. As long as the collector voltage and collector current stay within the RBSOA during the entire turnoff, the transistor will be undamaged. Typically the RBSOA will be specified for a variety of turn-off conditions, such as shorting the base to the emitter, but also faster turn-off protocols where

2541-403: Is widely used in consumer electronics , industrial technology , the energy sector , aerospace electronic devices, and transportation . The IGBT combines the simple gate-drive characteristics of power MOSFETs with the high-current and low-saturation-voltage capability of bipolar transistors . The IGBT combines an isolated-gate FET for the control input and a bipolar power transistor as

2618-990: The National Institute of Standards and Technology . Hefner's model is fairly complex but has shown good results. Hefner's model is described in a 1988 paper and was later extended to a thermo-electrical model which include the IGBT's response to internal heating. This model has been added to a version of the Saber simulation software. The failure mechanisms of IGBTs includes overstress (O) and wearout (wo) separately. The wearout failures mainly include bias temperature instability (BTI), hot carrier injection (HCI), time-dependent dielectric breakdown (TDDB), electromigration (ECM), solder fatigue, material reconstruction, corrosion. The overstress failures mainly include electrostatic discharge (ESD), latch-up, avalanche, secondary breakdown, wire-bond liftoff and burnout. Thyristor A thyristor ( / θ aɪ ˈ r ɪ s t ər / , from

2695-607: The SCR and diode never conduct at the same time they do not produce heat simultaneously and can easily be integrated and cooled together. Reverse conducting thyristors are often used in frequency changers and inverters . Photothyristors are activated by light. The advantage of photothyristors is their insensitivity to electrical signals, which can cause faulty operation in electrically noisy environments. A light-triggered thyristor (LTT) has an optically sensitive region in its gate, into which electromagnetic radiation (usually infrared )

2772-473: The ordinate ; the safe 'area' referring to the area under the curve. The SOA specification combines the various limitations of the device — maximum voltage, current, power, junction temperature , secondary breakdown — into one curve, allowing simplified design of protection circuitry. Often, in addition to the continuous rating, separate SOA curves are also plotted for short duration pulse conditions (1 ms pulse, 10 ms pulse, etc.). The safe operating area curve

2849-794: The 1980s and early 1990s were prone to failure through effects such as latchup (in which the device will not turn off as long as current is flowing) and secondary breakdown (in which a localized hotspot in the device goes into thermal runaway and burns the device out at high currents). Second-generation devices were much improved. The current third-generation IGBTs are even better, with speed rivaling power MOSFETs and excellent ruggedness and tolerance of overloads. Extremely high pulse ratings of second- and third-generation devices also make them useful for generating large power pulses in areas including particle and plasma physics , where they are starting to supersede older devices such as thyratrons and triggered spark gaps . High pulse ratings and low prices on

2926-804: The TRIAC to assure that it will turn off with each half-cycle of mains power. Inverse parallel SCRs can also be used in place of the triac; because each SCR in the pair has an entire half-cycle of reverse polarity applied to it, the SCRs, unlike TRIACs, are sure to turn off. The "price" to be paid for this arrangement, however, is the added complexity of two separate, but essentially identical gating circuits. Although thyristors are heavily used in megawatt-scale rectification of AC to DC, in low- and medium-power (from few tens of watts to few tens of kilowatts) applications they have virtually been replaced by other devices with superior switching characteristics like power MOSFETs or IGBTs . One major problem associated with SCRs

3003-444: The advantage over a standard circuit breaker or fuse in that it creates a high-conductance path to ground from damaging supply voltage and potentially for stored energy (in the system being powered). The first large-scale application of thyristors, with associated triggering diac , in consumer products related to stabilized power supplies within color television receivers in the early 1970s. The stabilized high voltage DC supply for

3080-469: The base-emitter voltage bias is reversed. The RBSOA shows distinct dependencies compared to the normal SOA. For example in IGBTs the high-current, high-voltage corner of the RBSOA is cut out when the collector voltage increases too quickly. Since the RBSOA is associated with a very brief turn-off process, it is not constrained by the continuous power dissipation limit. The ordinary safe operating area (when

3157-399: The change of polarity of the current causes the device to switch off automatically, referred to as " zero cross " operation. The device can be said to operate synchronously ; being that, once the device is triggered, it conducts current in phase with the voltage applied over its cathode to anode junction with no further gate modulation being required, i.e., the device is biased fully on . This

Insulated-gate bipolar transistor - Misplaced Pages Continue

3234-507: The control gate signal. The latter is known as a gate turn-off thyristor , or GTO thyristor. Unlike transistors , thyristors have a two-valued switching characteristic, meaning that a thyristor can only be fully on or off, while a transistor can lie in between on and off states. This makes a thyristor unsuitable as an analog amplifier, but useful as a switch. The silicon controlled rectifier (SCR) or thyristor proposed by William Shockley in 1950 and championed by Moll and others at Bell Labs

3311-451: The current). Safe operating area For power semiconductor devices (such as BJT , MOSFET , thyristor or IGBT ), the safe operating area (SOA) is defined as the voltage and current conditions over which the device can be expected to operate without self-damage. SOA is usually presented in transistor datasheets as a graph with V CE (collector-emitter voltage) on the abscissa and I CE (collector-emitter current) on

3388-422: The dV/dt (i.e., rate of voltage change over time). Snubbers are energy-absorbing circuits used to suppress the voltage spikes caused by the circuit's inductance when a switch, electrical or mechanical, opens. The most common snubber circuit is a capacitor and resistor connected in series across the switch (transistor). Since modern thyristors can switch power on the scale of megawatts , thyristor valves have become

3465-426: The design engineer working on power circuits such as amplifiers and power supplies as they allow quick assessment of the limits of device performance, the design of appropriate protection circuitry, or selection of a more capable device. SOA curves are also important in the design of foldback circuits. For a device that makes use of the secondary breakdown effect see Avalanche transistor Secondary breakdown

3542-414: The device at elevated temperatures by Baliga in 1985. Successful efforts to suppress the latch-up of the parasitic thyristor and the scaling of the voltage rating of the devices at GE allowed the introduction of commercial devices in 1983, which could be used for a wide variety of applications. The electrical characteristics of GE's device, IGT D94FQ/FR4, were reported in detail by Marvin W. Smith in

3619-409: The device design concept of non-latch-up IGBTs in 1984. The invention is characterized by the device design setting the device saturation current below the latch-up current, which triggers the parasitic thyristor. This invention realized complete suppression of the parasitic thyristor action, for the first time, because the maximal collector current was limited by the saturation current and never exceeded

3696-481: The device is in the on state) may be referred to as the Forward bias safe operating area (or FBSOA ) when it is possible to confuse it with the RBSOA. The most common form of SOA protection used with bipolar junction transistors senses the collector-emitter current with a low-value series resistor. The voltage across this resistor is applied to a small auxiliary transistor that progressively 'steals' base current from

3773-439: The device were initially regarded by the power electronics community to be severely restricted by its slow switching speed and latch-up of the parasitic thyristor structure inherent within the device. However, it was demonstrated by Baliga and also by A. M. Goodman et al. in 1983 that the switching speed could be adjusted over a broad range by using electron irradiation . This was followed by demonstration of operation of

3850-417: The device when used as an analog audio amplifier. As of 2010, the IGBT was the second most widely used power transistor, after the power MOSFET . An IGBT cell is constructed similarly to an n-channel vertical-construction power MOSFET , except the n+ drain is replaced with a p+ collector layer, thus forming a vertical PNP bipolar junction transistor . This additional p+ region creates a cascade connection of

3927-433: The device. By injecting minority carriers (holes) from the collector p+ region into the n- drift region during forward conduction, the resistance of the n- drift region is considerably reduced. However, this resultant reduction in on-state forward voltage comes with several penalties: In general, high voltage, high current and lower frequencies favor the IGBT while low voltage, medium current and high switching frequencies are

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4004-465: The domain of the MOSFET. Circuits with IGBTs can be developed and modeled with various circuit simulating computer programs such as SPICE , Saber , and other programs. To simulate an IGBT circuit, the device (and other devices in the circuit) must have a model which predicts or simulates the device's response to various voltages and currents on their electrical terminals. For more precise simulations

4081-483: The effect of temperature on various parts of the IGBT may be included with the simulation. Two common methods of modeling are available: device physics -based model, equivalent circuits or macromodels. SPICE simulates IGBTs using a macromodel that combines an ensemble of components like FETs and BJTs in a Darlington configuration . An alternative physics-based model is the Hefner model, introduced by Allen Hefner of

4158-425: The first thyristor. This method is called forced commutation. Once the current through the thyristor drops below the holding current, there must be a delay before the anode can be positively biased and retain the thyristor in the off-state. This minimum delay is called the circuit commutated turn off time ( t Q ). Attempting to positively bias the anode within this time causes the thyristor to be self-triggered by

4235-406: The gate terminal, the device remains latched in the on-state (i.e. does not need a continuous supply of gate current to remain in the on state), providing the anode current has exceeded the latching current ( I L ). As long as the anode remains positively biased, it cannot be switched off unless the current drops below the holding current ( I H ). In normal working conditions the latching current

4312-407: The gate-source voltage tends to be very close to the threshold voltage. Unfortunately the threshold voltage decreases as temperature increases, so that if there are any slight temperature variations across the chip, then the hotter regions will tend to carry more current than the cooler regions when Vgs is very close to Vth. This can lead to thermal runaway and the destruction of the MOSFET even when it

4389-416: The heart of high-voltage direct current (HVDC) conversion either to or from alternating current. In the realm of this and other very high-power applications, both electrically triggered (ETT) and light-triggered (LTT) thyristors are still the primary choice. Thyristors are arranged into a diode bridge circuit and to reduce harmonics are connected in series to form a 12-pulse converter . Each thyristor

4466-430: The latch-up current by controlling/reducing the saturation current of the inherent MOSFET. This was the concept of non-latch-up IGBT. "Becke’s device" was made possible by the non-latch-up IGBT. The IGBT is characterized by its ability to simultaneously handle a high voltage and a large current. The product of the voltage and the current density that the IGBT can handle reached more than 5 × 10 W/cm, which far exceeded

4543-410: The latch-up current. In the early development stage of IGBT, all the researchers tried to increase the latch-up current itself in order to suppress the latch-up of the parasitic thyristor. However, all these efforts failed because IGBT could conduct enormously large current. Successful suppression of the latch-up was made possible by limiting the maximal collector current, which IGBT could conduct, below

4620-399: The latch-up of the parasitic thyristor. Complete suppression of the parasitic thyristor action and the resultant non-latch-up IGBT operation for the entire device operation range was achieved by A. Nakagawa et al. in 1984. The non-latch-up design concept was filed for US patents. To test the lack of latch-up, the prototype 1200 V IGBTs were directly connected without any loads across

4697-420: The non-latch-up IGBT proposed by Hans W. Becke and Carl F. Wheatley was realized by A. Nakagawa et al. in 1984. Products of non-latch-up IGBTs were first commercialized by Toshiba in 1985. This was the real birth of the present IGBT. Once the non-latch-up capability was achieved in IGBTs, it was found that IGBTs exhibited very rugged and a very large safe operating area . It was demonstrated that

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4774-419: The non-latch-up IGBT was established in 1984 by solving the problem of so-called "latch-up", which is the main cause of device destruction or device failure. Before that, the developed devices were very weak and were easily destroyed by "latch-up". Practical devices capable of operating over an extended current range were first reported by B. Jayant Baliga et al. in 1982. The first experimental demonstration of

4851-421: The power device as it passes excess collector current. Another style of protection is to measure the temperature of the outside of the transistor, as an estimate of junction temperature, and reduce drive to the device or switch it off if the temperature is too high. If multiple transistors are used in parallel, only a few need to be monitored for case temperature to protect all parallel devices. This approach

4928-461: The proceedings of PCI April 1984. Smith showed in Fig. 12 of the proceedings that turn-off above 10 amperes for gate resistance of 5 kΩ and above 5 amperes for gate resistance of 1 kΩ was limited by switching safe operating area although IGT D94FQ/FR4 was able to conduct 40 amperes of collector current. Smith also stated that the switching safe operating area was limited by

5005-406: The product of the operating current density and the collector voltage exceeded the theoretical limit of bipolar transistors, 2 × 10 W/cm and reached 5 × 10 W/cm. The insulating material is typically made of solid polymers, which have issues with degradation. There are developments that use an ion gel to improve manufacturing and reduce the voltage required. The first-generation IGBTs of

5082-774: The receiver was obtained by moving the switching point of the thyristor device up and down the falling slope of the positive going half of the AC supply input (if the rising slope was used the output voltage would always rise towards the peak input voltage when the device was triggered and thus defeat the aim of regulation). The precise switching point was determined by the load on the DC output supply, as well as AC input fluctuations. Thyristors have been used for decades as light dimmers in television , motion pictures , and theater , where they replaced inferior technologies such as autotransformers and rheostats . They have also been used in photography as

5159-494: The remaining charge carriers ( holes and electrons ) that have not yet recombined . For applications with frequencies higher than the domestic AC mains supply (e.g. 50 Hz or 60 Hz), thyristors with lower values of t Q are required. Such fast thyristors can be made by diffusing heavy metal ions such as gold or platinum which act as charge combination centers into the silicon. Today, fast thyristors are more usually made by electron or proton irradiation of

5236-472: The secondary breakdown limit restricts the collector current more than the steady-state power dissipation of the device. Older power MOSFETs did not exhibit secondary breakdown, with their safe operating area being limited only by maximum current (the capacity of the bonding wires), maximum power dissipation and maximum voltage. This has changed in more recent devices as detailed in the next section. However, power MOSFETs have parasitic PN and BJT elements within

5313-416: The silicon, or by ion implantation . Irradiation is more versatile than heavy metal doping because it permits the dosage to be adjusted in fine steps, even at quite a late stage in the processing of the silicon. A reverse conducting thyristor (RCT) has an integrated reverse diode , so is not capable of reverse blocking. These devices are advantageous where a reverse or freewheel diode must be used. Because

5390-427: The similar thyristor was proposed by William Shockley in 1950 and developed in 1956 by power engineers at General Electric (GE). The metal–oxide–semiconductor field-effect transistor (MOSFET) was also invented at Bell Labs. In 1957 Frosch and Derick published their work on building the first silicon dioxide transistors, including a NPNP transistor, the same structure as the IGBT. The basic IGBT mode of operation, where

5467-402: The simplification they can bring to the electronics of an HVDC valve, light-triggered thyristors may still require some simple monitoring electronics and are only available from a few manufacturers. Two common photothyristors include the light-activated SCR (LASCR) and the light-activated TRIAC . A LASCR acts as a switch that turns on when exposed to light. Following light exposure, when light

5544-696: The structure, which can cause more complex localized failure modes resembling secondary breakdown. In their early history, MOSFETs became known for their absence of secondary breakdown. This benefit was due to the fact that ON-resistance increases with increasing temperature, so that part of the MOSFET which is running hotter (e.g. due to irregularities in the die-attachment, etc.) will carry a lower current density, tending to even out any temperature variation and prevent hot spots. Recently, MOSFETs with very high transconductance, optimised for switching operation, have become available. When operated in linear mode, especially at high drain-source voltages and low drain currents,

5621-514: The surplus market also make them attractive to the high-voltage hobbyists for controlling large amounts of power to drive devices such as solid-state Tesla coils and coilguns . As of 2010, the IGBT is the second most widely used power transistor , after the power MOSFET. The IGBT accounts for 27% of the power transistor market, second only to the power MOSFET (53%), and ahead of the RF amplifier (11%) and bipolar junction transistor (9%). The IGBT

5698-528: The thyristor operation or the latch-up in the four-layer device because the latch-up caused the fatal device failure. IGBTs had, thus, been established when the complete suppression of the latch-up of the parasitic thyristor was achieved. Later, Hans W. Becke and Carl F. Wheatley developed a similar device claiming non-latch-up. They patented the device in 1980, referring to it as "power MOSFET with an anode region" for which "no thyristor action occurs under any device operating conditions". A. Nakagawa et al. invented

5775-411: The value, 2 × 10 W/cm, of existing power devices such as bipolar transistors and power MOSFETs. This is a consequence of the large safe operating area of the IGBT. The IGBT is the most rugged and the strongest power device yet developed, affording ease of use and so displacing bipolar transistors and even gate turn-off thyristors (GTOs). This excellent feature of the IGBT had suddenly emerged when

5852-477: The voltage across the device is reverse-biased or the voltage is removed (by some other means), or through the control gate signal on newer types. Some sources define " silicon-controlled rectifier " (SCR) and "thyristor" as synonymous. Other sources define thyristors as more complex devices that incorporate at least four layers of alternating N-type and P-type substrate. The first thyristor devices were released commercially in 1956. Because thyristors can control

5929-452: Was developed in 1956 by power engineers at General Electric (GE), led by Gordon Hall and commercialized by GE's Frank W. "Bill" Gutzwiller. The Institute of Electrical and Electronics Engineers recognized the invention by placing a plaque at the invention site in Clyde, New York , and declaring it an IEEE Historic Milestone. An earlier gas-filled tube device called a thyratron provided

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