Precise characterization of long-distance mismatch of CMOS devices

A new test structure is presented for the characterization of long-distance mismatch of complimentary metal-oxide-semiconductor (CMOS) devices. A sing le circuit is used to characterize both transistors and resistors. High res olution is achieved by applying a four-terminal method with regulated refer ence potential to compensate for parasitic resistance effects. Measured dat a are presented for 0.5-, 0.35-, and 0.25-mum CMOS processes to demonstrate the performance of this approach. In particular, the long distance matchin g behavior is compared to that of neighboring devices. Examples for linear and nonlinear distance dependencies are shown. The long-distance mismatch h as to be taken into account in circuit designs with short channel transisto rs and with narrow resistors.