MOSFET devices

The salicide concept (self-aligned silicide) is now used extensively in MOSFET devices. It is based on TiSi2 and CoSi2, both of which are deposited by CVD.l k l The CVD reactions for the deposition of silicides are described in Ch. 12. 

The positive section of the power banks shown in Fig. 14 uses 40 type-N power Mosfet devices which can drive currents of up to 400 A. The same banks mount also 4 type-P devices for the negative section. The number of devices in the negative section is much smaller since the negative side is subject to much smaller power requirements. All 44 devices are mounted, together with their electronic control boards, on four special liquid-cooled, copper heat sinks. These, thanks to the excellent thermal conductivity of copper, combined with a design which maximizes the contact area between the copper and the cooling liquid, makes it possible to reach the requested cooling efficiency. 

Prom the electric point of view, each Mosfet device is equipped with its own driver circuit which, in a case of failure, disconnects it from the parallel array. This is very important since it permits the system to operate properly even when a few power components have burned out. It is also extremely... 

MOSFET devices have already been investigated in the literature and their overall characteristics seem to guarantee the possibility of producing either single or complex multifunction transducers. 

In general, the semiconductor is silicon and the oxide is silicon dioxide. The potential on the gate, which is the metal, can be varied to control the charge distribution at the oxide-semiconductor interface. The catalytic gate MOSFET device differs from an ordinary MOSFET in that the gate is metalized with palladium, Pd,... 

Figure 4.3.2. A schematic of a typical (a) ISFET device and (b) the analogous MOSFET device, (c) The current in the drain drcuit as a function of the drain voltage at various different gate voltages. When the gate voltage is negative (left portion of Figure) the n-p-n junction will not conduct and...

For the gate electrode of a MOSFET device to be a hydrogen sensor, the surface of the electrode has to be able to catalytically decompose the hydrogen... 

Ross et al (22) presented results on hydrogen and ammonia sensitivity of thin platinum-gate MOSFET devices. They concluded that the mechanism of response of these devices was as previously suggested, and cited literature on the dissociation of ammonia on silicon dioxide supported platinum catalysts as additional evidence. Lundstrom et al (23) presented further results on the two-metal capacitors. They outlined three possible modes of response of these devices, the first the same as the hydrogen sensitivity on palladium-gate devices (which they immediately ruled out), the second as already described. 

The ion-selective field-effect transistor (ISFET) is derived from the well-established MOSFET device familiar in silicon integrated circuits. Field effect devices have three major advantages to offer (see Chapter 10 of this volume). 

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