A new RF capacitance method to extract the effective channel length of MOSFET's using S-parameters

A simple and accurate extraction of the effective channel length is carried out by utilizing the slope information of the the intrinsic gate-to-channel capacitance versus the mask gate length of ultra short-channel devices. The measurement setup where the gate is connected to a RF signal is used to remove the discrepancy problem between conventional I-V and C-V methods. In order to increase the measurement accuracy, the intrinsic gate-to-channel capacitance data are determined by calibrating S-parameter sets measured at GHz using zero-bias data, instead of low-frequency C-V measurements. Contrary to the conventional C-V method, this new RF C-V method results in much smaller deviation from the I-V method.