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 the mainstream CMOS technology.
The first finfet transistor type was known under the name of fully Depleted Lean-channel TrAnsistor or DELTA transistor. Articles covering the DELTA transistor were first published in the beginning of the 1990s. 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.
The term FinFET (fin field-effect transistor) was coined in 2001 by University of California, Berkeley, researchers (Profs. Chenming Hu, Tsu-Jae King-Liu and Jeffrey Bokor) to describe a nonplanar, double-gate transistor built on an SOI substrate, based on the earlier DELTA (single-gate) transistor design.
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.
Intel's tri-gate transistors, where the gate surrounds the channel on three sides, allow 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.
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- Chenming Hu; Bokor, J.; et al. (December 2000). "FinFET-a self-aligned double-gate MOSFET scalable to 20 nm". IEEE Transactions on Electron Devices. 47 (12): 2320–2325. CiteSeerX 10.1.1.211.204. doi:10.1109/16.887014.
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- Intel 22nm 3-D Tri-Gate Transistor Technology