METHOD AND SYSTEM FOR ISOLATING DOPANT FLUCTUATION AND DEVICE LENGTH VARIATION FROM STATISTICAL MEASUREMENTS OF THRESHOLD VOLTAGE

摘要

A method and system for isolating dopant fluctuation and device length variation from statistical measurements of threshold voltage provides fast determination of process variation for devices in a characterization array. Statistics of threshold voltage are measured at two different values of drain-source voltage imposed on the devices in the characterization array. At least one moment of the a drain-induced barrier lowering (DIBL) coefficient eta, which is a measure of device length and zero-bias threshold voltage VTH0 are computed directly from the statistical moment values of the threshold variation. The standard deviation and mean of eta and VTH0 can thereby be obtained having only a statistical description of the threshold voltage for the devices in the array at multiple drain-source voltages. The threshold voltage statistics can be obtained from a digital meter measurement (rms and DC average) of a waveform indicative of threshold voltage produced by sequentially selecting the array devices.