(a) Why is there subthreshold conduction? Please draw the band diagram and explain. (b) What is the lower limit of the subthreshold swing for MOSFETs?
An n-channel MOSFET with a substrate doping concentration of Na = 2×1016 cm-3, a threshold voltage of VT = 0.4 V. The transistor is biased at VGS = 0.8 V and VDS = 2.5 V. Find the minimum channel length such that the ratio of actual drain current to the ideal drain current due to channel length modulation is no larger than 1.35.
