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 η, which is a measure of device length and zero-bias threshold voltage V_TH0 are computed directly from the statistical moment values of the threshold variation. The standard deviation and mean of η and V_TH0 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.