Dielectric layer of a MOSFET isolating the gate terminal from the underlying silicon
The gate oxide is the dielectric layer that separates the gate terminal of a MOSFET (metal–oxide–semiconductor field-effect transistor) from the underlying source and drain terminals as well as the conductive channel that connects source and drain when the transistor is turned on. Gate oxide is formed by thermal oxidation of the silicon of the channel to form a thin (5 - 200 nm) insulating layer of silicon dioxide. The insulating silicon dioxide layer is formed through a process of self-limiting oxidation, which is described by the Deal–Grove model. A conductive gate material is subsequently deposited over the gate oxide to form the transistor. The gate oxide serves as the dielectric layer so that the gate can sustain as high as 1 to 5 MV/cm transverse electric field in order to strongly modulate the conductance of the channel.
Above the gate oxide is a thin electrode layer made of a conductor which can be aluminium, a highly doped silicon, a refractory metal such as tungsten, a silicide (TiSi, MoSi2, TaSi or WSi2) or a sandwich of these layers. This gate electrode is often called "gate metal" or "gate conductor". The geometrical width of the gate conductor electrode (the direction transverse to current flow) is called the physical gate width. The physical gate width may be slightly different from the electrical channel width used to model the transistor as fringing electric fields can exert an influence on conductors that are not immediately below the gate.
The electrical properties of the gate oxide are critical to the formation of the conductive channel region below the gate. In NMOS-type devices, the zone beneath the gate oxide is a thin n-type inversion layer on the surface of the p-type semiconductor substrate. It is induced by the oxide electric field from the applied gate voltage VG. This is known as the inversion channel. It is the conduction channel that allows the electrons to flow from the source to the drain.[1]
Overstressing the gate oxide layer, a common failure mode of MOS devices, may lead to gate rupture or to stress induced leakage current.
During manufacturing by reactive-ion-etching the gate oxide may damaged by antenna effect.
^Fundamentals of Solid-State Electronics, Chih-Tang Sah. World Scientific, first published 1991, reprinted 1992, 1993 (pbk), 1994, 1995, 2001, 2002, 2006, ISBN 981-02-0637-2. -- ISBN 981-02-0638-0 (pbk).
The gateoxide is the dielectric layer that separates the gate terminal of a MOSFET (metal–oxide–semiconductor field-effect transistor) from the underlying...
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measurement can include gate–source and gate–drain overlap capacitances. Other scalings are not uncommon; the voltages and gateoxide thicknesses have not...
These new materials had a lower equivalent oxide thickness so they could retain an appropriate gateoxide thickness to prevent leakage current while also...
The antenna effect, more formally plasma induced gateoxide damage, is an effect that can potentially cause yield and reliability problems during the manufacture...
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developed a MOS gateoxide breakdown antifuse in 1979. A dual-gate-oxide two-transistor (2T) MOS antifuse was introduced in 1982. Early oxide breakdown technologies...
ellipsometry or reflectometry is used to tightly control the thickness of gateoxide, as well as the thickness, refractive index, and extinction coefficient...
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electric field across the gateoxide. Before scaling the design features down to 90 nm, a dual-oxide approach for creating the oxide thickness was a common...
{\displaystyle C_{d}} = depletion layer capacitance C o x {\displaystyle C_{ox}} = gate-oxide capacitance k T q {\displaystyle {kT \over q}} = thermal voltage The minimum...
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Complementary metal–oxide–semiconductor (CMOS, pronounced "sea-moss", /siːmɑːs/, /-ɒs/) is a type of metal–oxide–semiconductor field-effect transistor...
gate contact may be of polysilicon or metal, previously polysilicon was chosen over metal because the interfacing between polysilicon and gateoxide (SiO2)...
n-type PDSOI MOSFET the sandwiched n-type film between the gateoxide (GOX) and buried oxide (BOX) is large, so the depletion region can't cover the whole...
type of electronic noise that occurs in semiconductors and ultra-thin gateoxide films. It is also called random telegraph noise (RTN), popcorn noise,...
(polysilicon-oxynitride-nitride-oxide-silicon) structure with thickness of silicon dioxide less than 30 Å, and SIMOS (stacked-gate injection MOS) structure,...
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extreme stress on the thin dielectric layer; stressed oxide can shatter and fail immediately. The gateoxide itself does not fail immediately but can be accelerated...
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