Threshold voltage variation extracted from MOSFET C-V curves by charge-based capacitance measurement

The threshold voltage variations for the MOSFETs having various channel structures are evaluated from their measured capacitance-voltage (C-V) curves. It is found that they show reasonable dependence on the channel structure and smaller than those evaluated from the current-voltage (I-V) relations. As one of the reasons that the difference of between the variations extracted from C-V curves and those extracted from I-V relations arises, it is considered that the local channel dopant fluctuation increases the current variation. Furthermore, it is found that the evaluated flat-band voltage variations represent the reasonable behavior.