The body effect describes the changes in the threshold voltage by the change in, the source-bulk voltage. Since the body influences the threshold voltage (when it is not tied to the source), it can be thought of as a second gate, and is sometimes referred to as the "back gate"; the body effect is sometimes called the "back-gate effect".
For an enhancement mode, n-mos MOSFET body effect upon threshold voltage is computed according to the Shichman-Hodges model (accurate for very old technology) using the following equation.
where is the threshold voltage when substrate bias is present, is the source-to-body substrate bias, is the surface potential, and is threshold voltage for zero substrate bias, is the body effect parameter, is oxide thickness, is oxide permitivity, is the permitivity of silicon, is a doping concentration, is the charge of an electron.
Read more about this topic: Threshold Voltage
Famous quotes containing the words body and/or effect:
“And so I look on those sentiments which make the glory of the human being, love, humility, faith, as being also the intimacy of Divinity in the atoms; and, that, as soon as the man is right, assurances and previsions emanate from the interior of his body and his mind; as, when flowers reach their ripeness, incence exhales from them, and, as a beautiful atmosphere is generated from the planet by the averaged emanations from all its rocks and soils.”
—Ralph Waldo Emerson (1803–1882)
“Airplanes are invariably scheduled to depart at such times as 7:54, 9:21 or 11:37. This extreme specificity has the effect on the novice of instilling in him the twin beliefs that he will be arriving at 10:08, 1:43 or 4:22, and that he should get to the airport on time. These beliefs are not only erroneous but actually unhealthy.”
—Fran Lebowitz (b. 1950)