A fin field-effect transistor (FinFET) is a multigate device, a MOSFET (metal-oxide-semiconductor field-effect transistor) 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 (complementary metal-oxide-semiconductor) technology.
FinFET is a type of non-planar transistor, or "3D" transistor. It is the basis for modern nanoelectronic semiconductor device fabrication. Microchips utilizing FinFET gates first became commercialized in the first half of the 2010s, and became the dominant gate design at 14 nm, 10 nm and 7 nm process nodes.
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 first finfet transistor type was called a "Depleted Lean-channel Transistor" or "DELTA" transistor, which was first fabricated in Japan by Hitachi Central Research Laboratory's Digh Hisamoto, Toru Kaga, Yoshifumi Kawamoto and Eiji Takeda in 1989. The gate of the transistor can cover and electrically contact the semiconductor channel fin on both the top and the sides or only on the sides. The former is called a tri-gate transistor and the latter a double-gate transistor. A double-gate transistor optionally can have each side connected to two different terminal or contacts. This variant is called split transistor. This enables more refined control of the operation of the transistor.
Indonesian engineer Effendi Leobandung, while working at the University of Minnesota, published a paper with Stephen Y. Chou at the 54th Device Research Conference in 1996 outlining the benefit of cutting a wide CMOS transistor into many channels with narrow width to improve device scaling and increase device current by increasing the effective device width. This structure is what a modern FinFET looks like. Although some device width is sacrificed by cutting it into narrow widths, the conduction of the side wall of narrow fins more than make up for the loss, for tall fins. The device had a 35 nm channel width and 70 nm channel length.
The potential of Digh Hisamoto's research on DELTA transistors drew the attention of the Defense Advanced Research Projects Agency (DARPA), which in 1997 awarded a contract to a research group at UC Berkeley to develop a deep sub-micron transistor based on DELTA technology. The group was led by Hisamoto along with TSMC's Chenming Hu. The team made the following breakthroughs between 1998 and 2004.
- 1998 – N-channel FinFET (17 nm) – Digh Hisamoto, Chenming Hu, Tsu-Jae King Liu, Jeffrey Bokor, Wen-Chin Lee, Jakub Kedzierski, Erik Anderson, Hideki Takeuchi, Kazuya Asano
- 1999 – P-channel FinFET (sub-50 nm) – Digh Hisamoto, Chenming Hu, Xuejue Huang, Wen-Chin Lee, Charles Kuo, Leland Chang, Jakub Kedzierski, Erik Anderson, Hideki Takeuchi
- 2001 – 15 nm FinFET – Chenming Hu, Yang‐Kyu Choi, Nick Lindert, P. Xuan, S. Tang, D. Ha, Erik Anderson, Tsu-Jae King Liu, Jeffrey Bokor
- 2002 – 10 nm FinFET – Shibly Ahmed, Scott Bell, Cyrus Tabery, Jeffrey Bokor, David Kyser, Chenming Hu, Tsu-Jae King Liu, Bin Yu, Leland Chang
- 2004 – High-κ/metal gate FinFET – D. Ha, Hideki Takeuchi, Yang‐Kyu Choi, Tsu-Jae King Liu, W. Bai, D.‐L. Kwong, A. Agarwal, M. Ameen
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. 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.
The industry's first 25 nanometer transistor operating on just 0.7 volt was demonstrated in December 2002 by TSMC. The "Omega FinFET" design, named after the similarity between the Greek letter "Omega" and the shape in which the gate wraps around the source/drain structure, 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 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 2011, Intel demonstrated tri-gate transistors, where the gate surrounds the channel on three sides, allowing for increased energy efficiency and lower gate delay—and thus greater performance—over planar transistors.
Commercially produced chips at 22 nm and below have utilised FinFET gate designs. Intel's "Tri-Gate" variant were announced at 22nm in 2011 for its Ivy Bridge microarchitecture. These devices shipped from 2012 onwards. From 2014 onwards, at 14 nm (or 16 nm) major foundries (TSMC, Samsung, GlobalFoundries) utilised FinFET designs.
In 2013, SK Hynix began commercial mass-production of a 16 nm process, TSMC began production of a 16 nm FinFET process, and Samsung Electronics began production of a 10 nm process. TSMC began production of a 7 nm process in 2017, and Samsung began production of a 5 nm process in 2018. In 2019, Samsung announced plans for the commercial production of a 3 nm GAAFET process by 2021.
Commercial production of nanoelectronic FinFET semiconductor memory began in the 2010s. In 2013, SK Hynix began mass-production of 16 nm NAND flash memory, and Samsung Electronics began production of 10 nm multi-level cell (MLC) NAND flash memory. In 2017, TSMC began production of SRAM memory using a 7 nm process.
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The next major transistor innovation was the introduction of FinFET (tri-gate) transistors on Intel’s 22-nm technology in 2011.
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