Accuracy Assessment and Improvement of On-Chip Charge-Based Capacitance Measurements

Charge-Base Capacitance Measurement (CBCM) techniques provide a simple way for measuring the overall parasitic capacitance of on-chip interconnects [1]. However, CBCM suffers from charge injection that limits its accuracy and sensitivity. In this paper we provide extensive simulation and experimental results showing that the effects of charge injection cannot be neglected, nor completely compensated by means of differential measures. To overcome this limitation we propose a modified scheme that makes use of complementary pass-gates with compensating charge injection phenomena. Both the original and the enhanced CBCM techniques have been implemented in 0.18μm and 0.13μm CMOS processes. Comparative experimental results are reported and discussed.