A multigate device, multi-gate MOSFET or multi-gate field-effect transistor (MuGFET) refers to a MOSFET (metal–oxide–semiconductor field-effect transistor) that incorporates more than one gate into a single device. The multiple gates may be controlled by a single gate electrode, wherein the multiple gate surfaces act electrically as a single gate, or by independent gate electrodes. A multigate device employing independent gate electrodes is sometimes called a multiple-independent-gate field-effect transistor (MIGFET). The most widely used multi-gate devices are the FinFET (fin field-effect transistor) and the GAAFET (gate-all-around field-effect transistor), which are non-planar transistors, or 3D transistors.
Multi-gate transistors are one of the several strategies being developed by MOS semiconductor manufacturers to create ever-smaller microprocessors and memory cells, colloquially referred to as extending Moore's law. nm technologies. The primary roadblock to widespread implementation is manufacturability, as both planar and non-planar designs present significant challenges, especially with respect to lithography and patterning. Other complementary strategies for device scaling include channel strain engineering, silicon-on-insulator-based technologies, and high-κ/metal gate materials.Development efforts into multigate transistors have been reported by the Electrotechnical Laboratory, Toshiba, Grenoble INP, Hitachi, IBM, TSMC, UC Berkeley, Infineon Technologies, Intel, AMD, Samsung Electronics, KAIST, Freescale Semiconductor, and others, and the ITRS predicted correctly that such devices will be the cornerstone of sub-32
Dual-gate MOSFETs are commonly used in very high frequency (VHF) mixers and in sensitive VHF front-end amplifiers. They are available from manufacturers such as Motorola, NXP Semiconductors, and Hitachi.
Dozens of multigate transistor variants may be found in the literature. In general, these variants may be differentiated and classified in terms of architecture (planar vs. non-planar design) and the number of channels/gates (2, 3, or 4).
A planar double-gate MOSFET (DGMOS) employs conventional planar (layer-by-layer) manufacturing processes to create double-gate MOSFET (metal-oxide-semiconductor field-effect transistor) devices, avoiding more stringent lithography requirements associated with non-planar, vertical transistor structures. In planar double-gate transistors the drain–source channel is sandwiched between two independently fabricated gate/gate-oxide stacks. The primary challenge in fabricating such structures is achieving satisfactory self-alignment between the upper and lower gates.
20 years after the MOSFET was first demonstrated by Mohamed Atalla and Dawon Kahng of Bell Labs in 1960,the concept of a double-gate MOSFET was proposed by Toshihiro Sekigawa of the Electrotechnical Laboratory (ETL) in a 1980 patent describing the planar XMOS transistor. Sekigawa fabricated the XMOS transistor with Yutaka Hayashi at the ETL in 1984. They demonstrated that short-channel effects can be significantly reduced by sandwiching a fully depleted silicon-on-insulator (SOI) device between two gate electrodes connected together.
The ETL demonstration inspired Grenoble INP researchers including Francis Balestra, Sorin Cristoloveanu, M. Benachir and Tarek Elewa to fabricate a double-gate MOSFET using silicon thin film in 1987. The double-gate control of SOI transistors was used to force the whole silicon film (interface layers and volume) in strong inversion (called “Volume-Inversion MOSFET”) or strong accumulation (called “Volume-Accumulation MOSFET”). This method of transistor operation, demonstrating the electrostatic properties and scalability of multigate devices, offered strong device performance, particularly substantial increases in subthreshold slope, transconductance, and drain current. A simulation program and experiments on SIMOX structures was used to study this device.
Sekigawa fabricated an XMOS device with 2 µm gate length in 1987. In 1988, an IBM research team led by Bijan Davari fabricated 180 nm to 250 nm dual-gate CMOS devices. In 1992, Sekigawa fabricated a 380 nm XMOS device. In 1998, E. Suzuki fabricated a 40 nm XMOS device. The focus of DGMOS research and development (R&D) subsequently shifted away from planar DGMOS technology, towards non-planar FinFET (fin field-effect transistor) and GAAFET (gate-all-around field-effect transistor) technologies.
FlexFET is a planar, independently double-gated transistor with a damascene metal top gate MOSFET and an implanted JFET bottom gate that are self-aligned in a gate trench. This device is highly scalable due to its sub-lithographic channel length; non-implanted ultra-shallow source and drain extensions; non-epi raised source and drain regions; and gate-last flow. FlexFET is a true double-gate transistor in that (1) both the top and bottom gates provide transistor operation, and (2) the operation of the gates is coupled such that the top gate operation affects the bottom gate operation and vice versa.Flexfet was developed and is manufactured by American Semiconductor, Inc.
FinFET (fin field-effect transistor) is a type of non-planar transistor, or "3D" transistor (not to be confused with 3D microchips).The FinFET is a variation on traditional MOSFETs distinguished by the presence of a thin silicon "fin" inversion channel on top of the substrate, allowing the gate to make two points of contact: the left and right sides of the fin. The thickness of the fin (measured in the direction from source to drain) determines the effective channel length of the device. The wrap-around gate structure provides a better electrical control over the channel and thus helps in reducing the leakage current and overcoming other short-channel effects.
The first finfet transistor type was called a "Depleted Lean-channel Transistor" or "DELTA" transistor, which was first fabricated by Hitachi Central Research Laboratory's Digh Hisamoto, Toru Kaga, Yoshifumi Kawamoto and Eiji Takeda in 1989. nm process. The following year, they developed the first P-channel FinFETs. They coined the term "FinFET" (fin field-effect transistor) in a December 2000 paper.In the late 1990s, Digh Hisamoto began collaborating with an international team of researchers on further developing DELTA technology, including TSMC's Chenming Hu and a UC Berkeley research team including Tsu-Jae King Liu, Jeffrey Bokor, Xuejue Huang, Leland Chang, Nick Lindert, S. Ahmed, Cyrus Tabery, Yang‐Kyu Choi, Pushkar Ranade, Sriram Balasubramanian, A. Agarwal and M. Ameen. In 1998, the team developed the first N-channel FinFETs and successfully fabricated devices down to a 17
In current usage the term FinFET has a less precise definition. Among microprocessor manufacturers, AMD, IBM, and Freescale describe their double-gate development efforts as FinFETdevelopment, whereas Intel avoids using the term when describing their closely related tri-gate architecture. In the technical literature, FinFET is used somewhat generically to describe any fin-based, multigate transistor architecture regardless of number of gates.
A 25 nm transistor operating on just 0.7 volt was demonstrated in December 2002 by TSMC (Taiwan Semiconductor Manufacturing Company). The "Omega FinFET" design is named after the similarity between the Greek letter omega (Ω) and the shape in which the gate wraps around the source/drain structure. It has a gate delay of just 0.39 picosecond (ps) for the N-type transistor and 0.88 ps for the P-type.
In 2004, Samsung Electronics demonstrated a "Bulk FinFET" design, which made it possible to mass-produce FinFET devices. They demonstrated dynamic random-access memory (DRAM) manufactured with a 90 nm Bulk FinFET process. In 2006, a team of Korean researchers from the Korea Advanced Institute of Science and Technology (KAIST) and the National Nano Fab Center developed a 3 nm transistor, the world's smallest nanoelectronic device, based on FinFET technology. In 2011, Rice University researchers Masoud Rostami and Kartik Mohanram demonstrated that FINFETs can have two electrically independent gates, which gives circuit designers more flexibility to design with efficient, low-power gates.
In 2012, Intel started using FinFETs for its future commercial devices. Leaks suggest that Intel's FinFET has an unusual shape of a triangle rather than rectangle, and it is speculated that this might be either because a triangle has a higher structural strength and can be more reliably manufactured or because a triangular prism has a higher area-to-volume ratio than a rectangular prism, thus increasing switching performance.
In September 2012, GlobalFoundries announced plans to offer a 14-nanometer process technology featuring FinFET three-dimensional transistors in 2014. nm FinFETS in November 2013.The next month, the rival company TSMC announced start early or "risk" production of 16
In March 2014, TSMC announced that it is nearing implementation of several 16 nm FinFETs die-on wafers manufacturing processes:
AMD released GPUs using their Polaris chip architecture and made on 14 nm FinFET in June 2016. The company has tried to produce a design to provide a "generational jump in power efficiency" while also offering stable frame rates for graphics, gaming, virtual reality, and multimedia applications.
In March 2017, Samsung and eSilicon announced the tapeout for production of a 14 nm finFET ASIC in a 2.5D package.
This section needs to be updated.December 2016)(
A tri-gate transistor, also known as a triple-gate transistor, is a type of MOSFET with a gate on three of its sides.A triple-gate transistor was first demonstrated in 1987, by a Toshiba research team including K. Hieda, Fumio Horiguchi and H. Watanabe. They realized that the fully depleted (FD) body of a narrow bulk Si-based transistor helped improve switching due to a lessened body-bias effect. In 1992, a triple-gate MOSFET was demonstrated by IBM researcher Hon-Sum Wong.
Tri-gate fabrication is used by Intel for the non-planar transistor architecture used in Ivy Bridge, Haswell and Skylake processors. These transistors employ a single gate stacked on top of two vertical gates (a single gate wrapped over three sides of the channel), allowing essentially three times the surface area for electrons to travel. Intel reports that their tri-gate transistors reduce leakage and consume far less power than current transistors. This allows up to 37% higher speed or a power consumption at under 50% of the previous type of transistors used by Intel.
Intel explains: "The additional control enables as much transistor current flowing as possible when the transistor is in the 'on' state (for performance), and as close to zero as possible when it is in the 'off' state (to minimize power), and enables the transistor to switch very quickly between the two states (again, for performance)."Intel has stated that all products after Sandy Bridge will be based upon this design.
Intel announced this technology in September 2002.Intel announced "triple-gate transistors" which maximize "transistor switching performance and decreases power-wasting leakage". A year later, in September 2003, AMD announced that it was working on similar technology at the International Conference on Solid State Devices and Materials. No further announcements of this technology were made until Intel's announcement in May 2011, although it was stated at IDF 2011, that they demonstrated a working SRAM chip based on this technology at IDF 2009.
On April 23, 2012, Intel released a new line of CPUs, termed Ivy Bridge, which feature tri-gate transistors.Intel has been working on its tri-gate architecture since 2002, but it took until 2011 to work out mass-production issues. The new style of transistor was described on May 4, 2011, in San Francisco. Intel factories are expected to make upgrades over 2011 and 2012 to be able to manufacture the Ivy Bridge CPUs. As well as being used in Intel's Ivy Bridge chips for desktop PCs, the new transistors will also be used in Intel's Atom chips for low-powered devices.
The term tri-gate is sometimes used generically to denote any multigate FET with three effective gates or channels.
A gate-all-around (GAA) FET, abbreviated GAAFET, and also known as a surrounding-gate transistor (SGT),is similar in concept to a FinFET except that the gate material surrounds the channel region on all sides. Depending on design, gate-all-around FETs can have two or four effective gates. Gate-all-around FETs have been successfully characterized both theoretically and experimentally. They have also been successfully etched onto InGaAs nanowires, which have a higher electron mobility than silicon. GAAFETs are the successor to FinFETs, as they can work at sizes below 7nm.
A gate-all-around (GAA) MOSFET was first demonstrated in 1988, by a Toshiba research team including Fujio Masuoka, Hiroshi Takato, and Kazumasa Sunouchi, who demonstrated a vertical nanowire GAAFET which they called a "surrounding gate transistor" (SGT).Masuoka, best known as the inventor of flash memory, later left Toshiba and founded Unisantis Electronics in 2004 to research surrounding-gate technology along with Tohoku University. In 2006, a team of Korean researchers from the Korea Advanced Institute of Science and Technology (KAIST) and the National Nano Fab Center developed a 3 nm transistor, the world's smallest nanoelectronic device, based on gate-all-around (GAA) FinFET technology.
A multi-bridge channel FET (MBCFET) is similar to a GAAFET except for the use of nanosheets instead of nanowires.MBCFET is a word mark (trademark) registered in the U.S. to Samsung Electronics.
Planar transistors have been the core of integrated circuits for several decades, during which the size of the individual transistors has steadily decreased. As the size decreases, planar transistors increasingly suffer from the undesirable short-channel effect, especially "off-state" leakage current, which increases the idle power required by the device.
In a multigate device, the channel is surrounded by several gates on multiple surfaces. Thus it provides better electrical control over the channel, allowing more effective suppression of "off-state" leakage current. Multiple gates also allow enhanced current in the "on" state, also known as drive current. Multigate transistors also provide a better analog performance due to a higher intrinsic gain and lower channel length modulation.These advantages translate to lower power consumption and enhanced device performance. Nonplanar devices are also more compact than conventional planar transistors, enabling higher transistor density which translates to smaller overall microelectronics.
The primary challenges to integrating nonplanar multigate devices into conventional semiconductor manufacturing processes include:
BSIMCMG106.0.0,officially released on March 1, 2012 by UC Berkeley BSIM Group, is the first standard model for FinFETs. BSIM-CMG is implemented in Verilog-A. Physical surface-potential-based formulations are derived for both intrinsic and extrinsic models with finite body doping. The surface potentials at the source and drain ends are solved analytically with poly-depletion and quantum mechanical effects. The effect of finite body doping is captured through a perturbation approach. The analytic surface potential solution agrees closely with the 2-D device simulation results. If the channel doping concentration is low enough to be neglected, computational efficiency can be further improved by a setting a specific flag (COREMOD = 1).
All of the important multi-gate (MG) transistor behavior is captured by this model. Volume inversion is included in the solution of Poisson’s equation, hence the subsequent I–V formulation automatically captures the volume-inversion effect. Analysis of electrostatic potential in the body of MG MOSFETs provided a model equation for short-channel effects (SCE). The extra electrostatic control from the end gates (top/bottom gates) (triple or quadruple-gate) is also captured in the short-channel model.
Semiconductor device fabrication is the process used to manufacture semiconductor devices, typically the metal-oxide-semiconductor (MOS) devices used in the integrated circuit (IC) chips that are present in everyday electrical and electronic devices. It is a multiple-step sequence of photolithographic and chemical processing steps during which electronic circuits are gradually created on a wafer made of pure semiconducting material. Silicon is almost always used, but various compound semiconductors are used for specialized applications.
A transistor is a semiconductor device used to amplify or switch electronic signals and electrical power. It is composed of semiconductor material usually with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor's terminals controls the current through another pair of terminals. Because the controlled (output) power can be higher than the controlling (input) power, a transistor can amplify a signal. Today, some transistors are packaged individually, but many more are found embedded in integrated circuits.
Moore's law is the observation that the number of transistors in a dense integrated circuit doubles about every two years. The observation is named after Gordon Moore, the co-founder of Fairchild Semiconductor and was the CEO of Intel, whose 1965 paper described a doubling every year in the number of components per integrated circuit, and projected this rate of growth would continue for at least another decade. In 1975, looking forward to the next decade, he revised the forecast to doubling every two years, a compound annual growth rate (CAGR) of 40%.
The metal–oxide–semiconductor field-effect transistor (MOSFET, MOS-FET, or MOS FET), also known as the metal–oxide–silicon transistor (MOS transistor, or MOS), is a type of insulated-gate field-effect transistor (IGFET) that is fabricated by the controlled oxidation of a semiconductor, typically silicon. The voltage of the covered gate determines the electrical conductivity of the device; this ability to change conductivity with the amount of applied voltage can be used for amplifying or switching electronic signals. The MOSFET was invented by Egyptian engineer Mohamed M. Atalla and Korean engineer Dawon Kahng at Bell Labs in November 1959. It is the basic building block of modern electronics, and the most frequently manufactured device in history, with an estimated total of 13 sextillion (1.3 × 1022) MOSFETs manufactured between 1960 and 2018.
In semiconductor manufacturing, silicon on insulator (SOI) technology is fabrication of silicon semiconductor devices in a layered silicon–insulator–silicon substrate, to reduce parasitic capacitance within the device, thereby improving performance. SOI-based devices differ from conventional silicon-built devices in that the silicon junction is above an electrical insulator, typically silicon dioxide or sapphire. The choice of insulator depends largely on intended application, with sapphire being used for high-performance radio frequency (RF) and radiation-sensitive applications, and silicon dioxide for diminished short-channel effects in other microelectronics devices. The insulating layer and topmost silicon layer also vary widely with application.
The 90 nm process refers to the level of MOSFET (CMOS) fabrication process technology that was commercialized by the 2003–2005 timeframe, by leading semiconductor companies like Toshiba, Sony, Samsung, IBM, Intel, Fujitsu, TSMC, Elpida, AMD, Infineon, Texas Instruments and Micron Technology.
A fin field-effect transistor (FinFET) is a multigate device, a MOSFET built on a substrate where the gate is placed on two, three, or four sides of the channel or wrapped around the channel, forming a double gate structure. These devices have been given the generic name "finfets" because the source/drain region forms fins on the silicon surface. The FinFET devices have significantly faster switching times and higher current density than planar CMOS technology.
SONOS, short for "silicon–oxide–nitride–oxide–silicon", more precisely, "polycrystalline silicon"—"silicon dioxide"—"silicon nitride"—"silicon dioxide"—"silicon", is a cross sectional structure of MOSFET (metal-oxide-semiconductor field-effect transistor), realized by P.C.Y. Chen of Fairchild Camera and Instrument in 1977. This structure is often used for non-volatile memories, such as EEPROM and flash memories. It is sometimes used for TFT LCD displays. It is one of CTF (charge trap flash) variants. It is distinguished from traditional non-volatile memory structures by the use of silicon nitride (Si3N4 or Si9N10) instead of "polysilicon-based FG (floating-gate)" for the charge storage material. A further variant is "SHINOS" ("silicon"—"hi-k"—"nitride"—"oxide"—"silicon"), which is substituted top oxide layer with high-κ material. Another advanced variant is "MONOS" ("metal–oxide–nitride–oxide–silicon"). Companies offering SONOS-based products include Cypress Semiconductor, Macronix, Toshiba, United Microelectronics Corporation and Floadia.
The 22 nm node is the process step following the 32 nm in MOSFET (CMOS) semiconductor device fabrication. The typical half-pitch for a memory cell using the process is around 22 nm. It was first demonstrated by semiconductor companies for use in RAM memory in 2008. In 2010, Toshiba began shipping 24 nm flash memory chips, and Samsung Electronics began mass-producing 20 nm flash memory chips. The first consumer-level CPU deliveries using a 22 nm process started in April 2012.
The 130 nm process refers to the level of MOSFET (CMOS) semiconductor process technology that was commercialized around the 2001–2002 timeframe, by leading semiconductor companies like Fujitsu, IBM, Intel, Texas Instruments, and TSMC.
The 14 nm process refers to the MOSFET technology node that is the successor to the 22 nm node. The 14 nm was so named by the International Technology Roadmap for Semiconductors (ITRS). Until about 2011, the node following 22 nm was expected to be 16 nm. All 14 nm nodes use FinFET technology, a type of multi-gate MOSFET technology that is a non-planar evolution of planar silicon CMOS technology.
Nanoelectronics refers to the use of nanotechnology in electronic components. The term covers a diverse set of devices and materials, with the common characteristic that they are so small that inter-atomic interactions and quantum mechanical properties need to be studied extensively. Some of these candidates include: hybrid molecular/semiconductor electronics, one-dimensional nanotubes/nanowires or advanced molecular electronics.
Nanocircuits are electrical circuits operating on the nanometer scale. This is well into the quantum realm, where quantum mechanical effects become very important. One nanometer is equal to 10−9 meters or a row of 10 hydrogen atoms. With such progressively smaller circuits, more can be fitted on a computer chip. This allows faster and more complex functions using less power. Nanocircuits are composed of three different fundamental components. These are transistors, interconnections, and architecture, all fabricated on the nanometer scale.
In semiconductor fabrication, the International Technology Roadmap for Semiconductors (ITRS) defines the 10 nm process as the MOSFET technology node following the 14 nm node. "10 nm class" denotes chips made using process technologies between 10 and 20 nm.
In semiconductor manufacturing, the International Roadmap for Devices and Systems defines the 5 nm process as the MOSFET technology node following the 7 nm node. As of 2019, Samsung Electronics and TSMC have begun limited risk production of 5 nm nodes, and are planning to begin mass production in 2020.
In semiconductor manufacturing, the International Technology Roadmap for Semiconductors defines the 7 nm process as the MOSFET technology node following the 10 nm node. It is based on FinFET technology, a type of multi-gate MOSFET technology.
The field-effect transistor (FET) is a type of transistor which uses an electric field to control the flow of current. FETs are devices with three terminals: source, gate, and drain. FETs control the flow of current by the application of a voltage to the gate, which in turn alters the conductivity between the drain and source.
In semiconductor manufacturing, the 3 nm process is the next die shrink after the 5-nanometre MOSFET technology node. As of 2019, Samsung and TSMC have announced plans to put a 3 nm semiconductor node into commercial production. It is based on GAAFET technology, a type of multi-gate MOSFET technology.
Tsu-Jae King Liu is the Dean and Roy W. Carlson Professor of Engineering at the University of California, Berkeley. She is the first woman in the history of UC Berkeley to serve as Dean of the College of Engineering. Currently only 60 of the 368 engineering colleges and schools in the United States have female deans.