THE FLOATING-GATE MEASUREMENT TECHNIQUE FOR CHARACTERIZATION OF CAPACITOR MATCHING

This paper discusses a new method for characterization of matching of capacitors using the so-called floating gate capacitance measurement m ethod [1]. After an introduction of this measurement method, modificat ions are discussed that were implemented to boost the measurement accu racy and repeatability from its original thousands of ppm's (0.1 to 0. 3%) to values as low as 50 ppm (0.005%), Instrumental in these improve ments are the introduction of a double slope measurement procedure to compensate for systematic offsets, as well as the use of repeated meas urements and averaging to reduce the influence of the measurements sys tem's noise, The improved accuracy, including statistical characteriza tion of the measurement system's short term repeatability, are require d for correct determination of capacitor matching of the extremely wel l-matching double-polysilicon capacitor structures that were used for this study.