Test structure for precise statistical characteristics measurement of MOSFETs

A new test structure consisting of an MOSFET array and peripheral decoder circuits is proposed to study statistical variation (mismatch) in MOSFETs' characteristics. Kelvin technique was implemented in the structure to cancel parasitic resistance of metal wiring and transmission gates in such a way that any MOSFET in the array can be measured at the same bias condition. Accurate electrical measurements using the structure makes it possible to derive statistical variation of threshold voltage and transconductance of MOSFETs placed in small area.