Mismatch of lateral field metal-oxide-metal capacitors in 180 nm CMOS process

Metal-oxide-metal (MOM) capacitors represent an attractive alternative to metal-insulator-metal (MIM) capacitors in mixed-signal integrated circuits. Since they are made of metal lines, they can be integrated in standard CMOS processes, and tailored over a wide range of sizes. Mismatch data of MOM capacitors, however, is scarce and typically conservative. Presented is the design and the test results of a custom ADC that employs an array of 1024 MOM capacitors sized at 2 fF. Static performance metrics are presented and compared with those for an ADC based on MIM capacitors. Mismatch data is computed from the results.