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:
“Life. A spiritual pickle preserving the body from decay.”
—Ambrose Bierce (1842–1914)
“As soon as I suspect a fine effect is being achieved by accident I lose interest. I am not interested ... in unskilled labor.... The scientific actor is an even worker. Any one may achieve on some rare occasion an outburst of genuine feeling, a gesture of imperishable beauty, a ringing accent of truth; but your scientific actor knows how he did it. He can repeat it again and again and again. He can be depended on.”
—Minnie Maddern Fiske (1865–1932)