Metal–oxide–semiconductor structure, Electrical Engineering

Metal-Oxide-Semiconductor Structure

A traditional metal-oxide-semiconductor abbreviated as MOS structure is acquired by growing a layer of silicon dioxide (SiO2) on top of a silicon substrate and depositing a layer of metal or polycrystalline silicon (the latter is typically used). Since the silicon dioxide is a dielectric material, its structure is equal to a planar capacitor, along with one of the electrodes replaced by a semiconductor.

While a voltage is applied across a MOS structure, it changes the distribution of charges in the semiconductor. If we refer a P-type semiconductor (along with NA the density of acceptors, p the density of holes; p = NA in neutral bulk), a positive (+ive) voltage, VGB, from gate to body (see figure) forms a depletion layer by forcing the positively charged holes away from the gate-insulator or semiconductor interface, leaving exposed a carrier-free region of immobile, negatively charged acceptor ion. If VGB is sufficiently high, a high concentration of negative charge carriers forms in an inversion layer situated in a thin layer next to the interface in between the semiconductor and the insulator. Not like the MOSFET, in which the inversion layer electrons are supplied fast from the source or drain electrodes, in the MOS capacitor they are generated much more slowly by thermal generation by carrier generation and recombination centers in the depletion region.

145_Metal–oxide–semiconductor structure.png

                                      Figure: MOSFET structure and channel formation

Usually, the gate voltage at which the volume density of electrons in the inversion layer is similar as the volume density of holes in the body is called the threshold voltage. This structure along with p-type body is the basis of the N-type MOSFET that needs the addition of an N-type source and drain regions.

Posted Date: 1/11/2013 1:13:56 AM | Location : United States







Related Discussions:- Metal–oxide–semiconductor structure, Assignment Help, Ask Question on Metal–oxide–semiconductor structure, Get Answer, Expert's Help, Metal–oxide–semiconductor structure Discussions

Write discussion on Metal–oxide–semiconductor structure
Your posts are moderated
Related Questions
Explain the Working of Frequency Division? A frequency divider able to be constructed from J-K flip-flops by taking the output of one cell to the clock input of the next and th

I need help designing a BJT amplifier with that meets the following parameters: voltage gain greater than 300, Ic(Vce=0)=2uA, Vcc=20V.

Explain Mobility . Average drift velocity of electrons (e - ) in an applied field is proportional to the field, the absolute magnitude of the proportionality factor eq/m, termed

Explain Diffusion. Diffusion : Though, the mobility of the carriers in a semiconductor is greater than the electrons in metals, the conductivity in the former is much less t

Determine Total magnetic flux: A ring is composed of three sections. The cross-sectional area is 0.001 m2 for each section. The mean lengths of each section are l a = 0.3 m,

i am going to make a sinusoidal inverter as my final year project kindly help me in this regard.How can i make this project?

Q. Consider Figure of the weighted differencing amplifier. Let R 3 = R 1 and R 4 = R 2 . Determine the input resistance between terminals a and b of the circuit.

A 3-phase, wye-connected, 11.8 kV, 100 MVA turbo- generator of 0.8 power factor lagging has a synchronous reactance of 2.0 p.u. on rating. The generator is driven by a steam turbin

Q. Regions of operation in BJT ? Transistor find many applications like amplifier, switch etc. depending upon the polarity and the magnitude of the applied voltages across the

1- Phase Full  Bridge  inverter will RL Load For a  resistive load R the load  current  wave form  will be  identical with load  voltage wave form  and feedback  diodes will