Editing MOSFET (section)

===Drain-induced barrier lowering and ''V''<sub>T</sub> roll off===
[[Drain-induced barrier lowering]] (DIBL) and ''V''<sub>T</sub> roll off: Because of the [[short-channel effect]], channel formation is not entirely done by the gate, but now the drain and source also affect the channel formation. As the channel length decreases, the depletion regions of the source and drain come closer together and make the threshold voltage (''V''<sub>T</sub>) a function of the length of the channel. This is called ''V''<sub>T</sub> roll-off. ''V''<sub>T</sub> also becomes function of drain to source voltage ''V''<sub>DS</sub>. As we increase the ''V''<sub>DS</sub>, the depletion regions increase in size, and a considerable amount of charge is depleted by the ''V''<sub>DS</sub>. The gate voltage required to form the channel is then lowered, and thus, the ''V''<sub>T</sub> decreases with an increase in ''V''<sub>DS</sub>. This effect is called drain induced barrier lowering (DIBL).