Abstract The matching property of MOS capacitors has been studied in accordance with well established statistical principles and on the basis of the experimentally generated data. Various random error mechanisms have been studied in a systematic manner. For edge-related errors, structures with approximately equal area but differing perimeters have been considered. Similarly, for corner-related errors, structures having approximately the same area and perimeter but a different number of corners have been studied. Some empirical relationships have been obtained. For the presently considered dimensions and technology, normalized random error in capacitor-ratio has been observed to have (i) an inverse square-root dependence upon the capacitor-area; (ii) a linear dependence upon the perimeter-to-area ratio; and (iii) a very weak dependence, n 1 6 , upon the capacitor-ratio n . “Statistically highly significant” improvement in matching has been observed for hitherto unreported structure in which photolithographically defined corners are completely avoided. Application of the above “corner-less” configuration would result in a considerable saving of the capacitor-area in switched-capacitor, A/D and D/A converter applications. For realizing small real ratios, use of rectangular and ring-type structures is proposed. “Statistically significant” improvement in capacitor-matching has been obtained for such structures even though the perimeter-to-area ratio ( P / A ) of such structures is greater than the corresponding square-geometry ones.
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