C-V Characterization of Nonlinear Capacitors using CBCM Method

The paper deals with a modification of CBCM (charge-based capacitance measurements) for nonlinear capacitance characterization. The method is characterized by high resolution although it is based on equipment found in any average laboratory. CBCM was originally developed for linear interconnect measurements. The proposed modification uses two DC swept sources to measure the whole nonlinear Q-v characteristic in both polarities without the necessity to switch the measured object. A test-chip implementing the method was designed and manufactured in 0.35 mum CMOS process. Verification against known capacitances proved the method correctness and accuracy. It was successfully used for MOSCAPs characterization in full operating voltage range.