New test structures for on-chip absolute and accurate measurement of capacitances in a CMOS process

A new on-chip capacitance measurement technique is presented. Since no reference devices are required, it allows the absolute determination of constant capacitances and matching errors are greatly reduced. The test structure can be easily scaled to any CMOS process and can be used with unstable or not totally characterized processes. Experimental results show an accuracy better than 5% and a resolution of about 1% for capacitances varying from 4 up to 135 fF.<
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