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:
“Play for young children is not recreation activity,... It is not leisure-time activity nor escape activity.... Play is thinking time for young children. It is language time. Problem-solving time. It is memory time, planning time, investigating time. It is organization-of-ideas time, when the young child uses his mind and body and his social skills and all his powers in response to the stimuli he has met.”
—James L. Hymes, Jr. (20th century)
“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)