N-channel metal oxide semiconductor

Gate oxide dielectrics are a cmcial element in the down-scaling of n- and -channel metal-oxide semiconductor field-effect transistors (MOSEETs) in CMOS technology. Ultrathin dielectric films are required, and the 12.0-nm thick layers are expected to shrink to 6.0 nm by the year 2000 (2). Gate dielectrics have been made by growing thermal oxides, whereas development has turned to the use of oxide/nitride/oxide (ONO) sandwich stmctures, or to oxynitrides, SiO N. Oxynitrides are formed by growing thermal oxides in the presence of a nitrogen source such as ammonia or nitrous oxide, N2O. Oxidation and nitridation are also performed in rapid thermal processors (RTP), which reduce the temperature exposure of a substrate. 

MOSFETs. The metal-oxide-semiconductor field effect transistor (MOSFET or MOS transistor) (8) is the most important device for very-large-scale integrated circuits, and it is used extensively in memories and microprocessors. MOSFETs consume little power and can be scaled down readily. The process technology for MOSFETs is typically less complex than that for bipolar devices. Figure 12 shows a three-dimensional view of an n-channel MOS (NMOS) transistor and a schematic cross section. The device can be viewed as two p-n junctions separated by a MOS capacitor that consists of a p-type semiconductor with an oxide film and a metal film on top of the oxide. 

The metal oxide-semiconductor field effect transistor (MOSFET) is the most important component in modem electronics, at least from the perspective of sheer numbers. A typical computer chip contains vast numbers of MOS-FETs. The basic architecture is illustrated in Eigure 1. The semiconductor is connected to a substrate on one side and to a gate contact on the other, which is separated from the semiconductor by a dielectric film. The region of semiconductor directly beneath the gate connects two contacts, the source and the drain. If the semiconductor is p-type Si, then source and drain contacts may be formed by implantation of electron-rich elements to yield shallow regions composed of n-type material. As the potential difference between the gate and the substrate is increased, the channel between the... 

The device that supports Moore s Law, known as the metal-oxide semiconductor field-effect transistor (MOSFET), comes in both n-channel and p-channel flavors depending on whether the primary current is carried by electrons or... 

Of course it is possible to reserve the polarities of these field-effect devices by exchanging the n- and p-materials. For many applications it is desirable to operate n- and p-devices side-by-side on the same substrate. This is accomplished by p-doping a region in an n-type substrate large enough to accommodate an n-channel device so that it may work in parallel with an adjacent p-channel device. Such a combination is called complimentary metal oxide semiconductors (CMOS). 

En me sensors involving semiconductors are called enzyme field-effect transistors, ENFET, and, as their name implies, exploit the association of an en me with a field-effect transistor (Fl. The transistor has a metal oxide semiconductor field-effect transistor (MOSFET) structure, which is constructed from, for example, a p-type silicon substrate (Figure 4.30). This central channel is defined by placing two n-type semiconducting zones, called the source and the drain, on opposite sides of the substrate. A metallic gate is isolated from the channel by a thin insulating film (Si02), which also covers the upper face of the substrate. 

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